Are Chinese Edible Oils Safe A Survey of Trans Fatty Acid.
Food Sci. Biotechnol. 25(2): 631-636 (2016)
DOI 10.1007/s10068-016-0088-5
Are Chinese Edible Oils Safe? A Survey of Trans Fatty Acid Contents in Chinese Edible Oils
Xiaojun Huang, Shaoping Nie*, Meiyan Yang, Jianhua Xie, Chang Li, and Mingyong Xie
State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China
Introduction
Trans fatty acids (TFAs) are unsaturated fatty acids with 1 or more
non-conjugated double bonds in a trans conguration (1). TFAs are
mostly produced using industrial hydrogenation and partially from
bio-hydrogenation in the rumen of ruminants (2). Unlike other
dietary fats, TFAs are neither essential nor salubrious and are, in fact,
harmful to human health. Reports have demonstrated that intake of
high levels of TFAs can increase the risk of cardiovascular disease
(CVD) (3), cancer, obesity, diabetes (4) and even allergies (2). Therefore,
TFA safety evaluation of foods has attracted public attention.
Variations in TFA amounts in foods from Western countries have
been reported (1,2) in recent decades. However, in China, current
TFA contents and TFA risk management have seldom been reported.
In addition, Chinese food safety issues have occurred frequently in
recent years, affecting consumer confidence both at home and
abroad. Both governmental and food industry practitioners have
made great efforts to ensure food safety and improve food quality.
Therefore, scientific surveys of TFA contents in Chinese foods and risk
assessments are of great importance.
Edible oils, the most commonly used ingredient in Chinese
traditional cooking, should never be overlooked. Hou et al. (5) made
an assessment of TFA contents in Chinese edible oils in 2011 based
on a total of 93 samples collected from a single city, which did not
represent the entire situation in China. Consequently, in this study,
165 oil samples were collected from 7 cities in China for study of TFA
contents, and an exposure assessment and a risk assessment were
performed for evaluation of the safety and quality of oil products.
Materials and Methods
Oil sample collection and preparation Commonly consumed edible
oils from 9 different sources as a total of 165 samples including
rapeseed oil (RSO), tea oil (TO), soybean oil (SBO), peanut oil (PNO),
salad oil (SO), corn oil (CO), lard (L), palm oil (PO), and blended oil
(BO) were purchased from supermarkets in Harbin, Lanzhou,
Chongqing, Wuhan, Shijiazhuang, Guangzhou, and Nanjing, located
in different areas of China. Harbin and Shijiazhuang are located in the
southeast, Lanzhou is located in the southwest, Chongqing is located
in the northwest, Wuhan is located in the middle, Guangzhou is
located in the north, and Nanjing is located in the east near the
ocean. Three product brands were collected for each oil type in each
city. Manufacture dates of oils were in the same year within a 3-
month period. Oil samples were stored in clean opaque bottles at
room temperature prior to analysis.
The American Oil Chemists’ Society (AOCS) (6,7) method for
determination of TFA contents in foods was used with minor
modification. An amount of 1.5-2.0 mg of oil and 10μL of a 4.5mg/
mL internal standard (C21:0) (Sigma-Aldrich, St. Louis, MO, USA),
were dissolved in 1.5 mL of n-hexane (Aladdin Reagents, Shanghai,
China). Then, 40μL of methyl acetate (Aladdin Reagents) and 100μL
of methanolic sodium methoxide (Aladdin Reagents) were added
and allowed to react at 65o C for 40 min for formation of fatty acid
methyl esters (FAME).
FAME profiles were determined using an Agilent 6890N capillary
gas chromatograph (Agilent Technologies, Santa Clara, CA, USA)
equipped with a flame ionization detector (FID). A CP-Sil88 capillary Received July 11, 2015
Revised November 23, 2015
Accepted November 23, 2015
Published online April 30, 2016
*Corresponding Author
Tel/Fax: +86-791-88304452
E-mail: spnie@https://www.sodocs.net/doc/bc16046443.html,
pISSN 1226-7708
eISSN 2092-6456
? KoSFoST and Springer 2016
Abstract Nine different edible oil types from 7 cities in China were analyzed. Trans fatty acid (TFA)
contents in edible oils were determined, TFA distribution characteristics were analyzed, and a risk
assessment was performed. Total TFA contents varied from 0.075±0.011 to 2.243±0.770 g/100 g of oil,
with a mean content of 0.66 g/100 g of oil. TFA contents differed among different oil types and among
different cities. Generally speaking, oil samples from northern areas of China contained more TFA, and
lard usually had higher levels of TFA than other oils. An exposure assessment showed that the
estimated daily intake of TFA from Chinese edible oils was low, and a risk assessment indicated that
there was a low risk for TFA consumption in Chinese edible oils.
Keywords: edible oil,trans fatty acid, risk assessment
632Huang et al.
Food Sci. Biotechnol.
column (100 m×0.25 mm×0.2μm) (Varian-Chrompack, Middelburg,The Netherlands) was used (5). The injector temperature was 250o C and 1.0μL of an oil sample was injected into the GC. The temperature program was 45o C for 4 min, increased by 13o C/min to 175o C, then increased by 4o C/min to 215o C. Conditions for the FID detector were 250o C and flow rates for H 2, air, and N 2 were 30.0 mL/min.
Individual FAME species were identified based on comparison of retention times with corresponding GLC-463 reference oil samples (Nu-Chek-Prep, Elysian, MN, USA). Quantification was achieved using internal standards (Sigma-Aldrich). Oil samples contained few TFA isomers and only contents of 9t C16:1, trans C18:1, and 9t 12t C18:2were calculated. Each trans C18:1 variety did not completely separate leading to calculation as a whole. The sum of the 3 isomer contents was calculated as the total TFA content.
All values are shown as a mean and standard deviation (SD) of 3replicates. Statistical analysis was performed using the analysis of variance (ANOVA) function of SPSS 11.5 (IBM, Chicago, IL, USA) for Windows. Significance was defined as p <0.05.
Exposure assessment for edible oils in China Crystal Ball was used for assessment of exposure conditions for total TFA for oils in this study. Estimated Daily Intake (EDI) values of total TFA values in oils were calculated as (8):
EDI=where Cf is the total TFA content (%) and PTR is the average daily consumption of edible oils per person. The PTR value in 2010 was approximately 0.0414 kg/person/day (8). The absorption coefficient (ABS) is usually=1 (8). The exposure frequency (EF) indicates days of oil consumption per year, and is usually=365 days/year (8). The exposure duration (ED) is considered as a lifetime. The average lifetime for Chinese residents was 69.63 years for males and 73.33years for females in 2009 (8,9). The averaged time (AT) value was calculated as: AT=ED year×365 day/year .
TFA risk assessment for Chinese edible oils A risk assessment model was first established including hazard identification, does-response assessment, exposure assessment, and risk characterization (9). Then Crystal Ball was used for calculation of the hazard quotient (HQ) as (10):
HQ=where RfD is a TFA reference dosage calculated based on reported
World Health Organization statistics (8). The RfD value for TFA in 2003 was 2.2 g/person/day (8,11).
An HQ value <1 indicated that the total TFA intake from Chinese edible oils did not reach a critical value (8), indicating no risk for TFA consumption. Otherwise, there was a risk for TFA consumption and the higher the HQ value, the higher the risk.
Results and Discussion
TFA contents in different oils from different cities A summary of TFA contents (g/100 g of oil) of all oil samples is shown in Table 1.TFAs were detected in all oil samples with total concentrations varying from 0.075±0.011 to 2.243±0.770 g/100 g of oil with a mean content of 0.66±1.009 g/100 g of oil. Most oil samples contained less than 2 g/100 g of oil, except lard from Guangzhou at 2.227±0.391 g/100 g of oil and soybean oil from Shijiazhuang at 2.243±0.770 g/100 g of oil. In all, 49.0% of oil samples exhibited a TFA content of less than 0.3 g/100 g of oil, while oil samples with TFA contents between 0.5-1.0 g/100 g of oil and between 1.0 and 2.0 g/100 g of oil constituted approximately 23.6% of all oil samples.
TFA contents differed among different sources and among different cities. Detailed TFA content distribution characteristics and a comparison of TFA contents among different cities (A) and among different oils (B) are shown in Fig. 1. Rapeseed oil, tea oil, and salad oil purchased from different cities exhibited no significant (p <0.05)differences in total TFA contents (Fig. 1A). However, soybean oil,peanut oil, and blended oil from Shijiazhuang contained significantly (p <0.05) more TFAs than oils from other cities with mean concentration values of 2.243±0.770, 1.632±1.541, 1.979±2.082 g/100 g of oil,respectively. The TFA content in corn oil from Chongqing of 1.932±0.072 g/100 g of oil was significantly (p <0.05) higher than corn oils from other cities. Lard obtained from Wuhan, with a TFA content of 0.141±0.086 g/100 g of oil, had the lowest TFA content. Lard from Harbin at 1.989±0.279 g/100 g of oil, Lanzhou at 1.671±0.196 g/100 g of oil, and Guangzhou at 2.227±0.391 g/100 g of oil had significantly (p <0.05) higher TFA contents than lard samples from other cities.Palm oil from Wuhan, with a TFA content of 0.103±0.019 g/100 g of oil, also exhibited the lowest TFA content of oils from Wuhan, while blended oil from Shijiazhuang at 1.979±2.082 g/100 g of oil exhibited the highest TFA content.
Generally speaking, oils with a high TFA content were usually from northern areas. Light industries, such as food processing and textiles are developed in the prosperous southern part of China; while heavy industry dominates the northern areas of China. Therefore, oil production techniques in northern cities may not be as well developed or as efficient as in southern cities and this might account for higher TFA contents in oils from northern cities. Lard from Guangzhou had the highest TFA content of all oil samples.
Wuhan, Shijiazhuang, and Nanjing oil samples showed no significant (p >0.05) differences in TFA contents (Fig. 1B). In Harbin,lard and palm oil had the highest (1.989±0.279 g/100 g of oil) and the second highest (1.617±0.033 g/100 g of oil) TFA contents among Harbin oil samples. In Lanzhou, lard and palm oils contained significantly (p <0.05) higher TFA contents than other Lanzhou oil types with mean concentration values of 1.671±0.196 and 1.498±0.341 g/100 g of oil, respectively. The TFA content in Chongqing corn oil at 1.932±0.072 g/100 g of oil ranked highest among all Chongqing oil samples. The TFA content in Lanzhou lard at 1.671±0.196 g/100 g
Cf PTR ×ABS ×EF ×ED ×AT 100
×----------------------------------------------------Cf PIR ×ABS ×EF ×ED ×AT RfD ×100
×---------------------------------------------------
Survey of Trans Fatty Acid in Edible Oils633
Table 1. TFA contents in oil samples(unit: g/100 g of oil)
9t C16:1trans C18:19t 12t C18:2Total trans Rapeseed oil (RSO)
Lanzhou ND1)0.123±0.0990.012±0.0100.135±0.109
Chongqing0.002±0.0012)0.118±0.0440.007±0.0010.127±0.050
Guangzhou ND0.079±0.0160.010±0.0040.088±0.014
Nanjing ND0.185±0.0590.008±0.0010.193±0.055
Tea oil (TO)
Lanzhou ND0.098±0.0410.008±0.0010.106±0.041
Shijiazhuang ND0.670±0.0560.017±0.0020.687±0.058
Guangzhou ND0.511±0.0460.009±0.0010.520±0.657
Nanjing0.015±0.013 1.176±0.3490.116±0.095 1.307±1.203 Soybean oil (SBO)
Harbin ND0.073±0.0060.002±0.0010.075±0.011
Lanzhou ND0.073±0.0080.008±0.0030.081±0.011
Chongqing ND0.497±0.7260.069±0.1010.567±0.827
Wuhan ND0.127±0.0230.041±0.0420.169±0.037
Shijiazhuang ND 1.986±0.7060.257±0.065 2.243±0.770
Guangzhou ND0.091±0.0140.004±0.0030.095±0.011
Nanjing ND0.675±0.9890.097±0.1210.772±1.110 Peanut oil (PNO)
Harbin ND0.093±0.0190.003±0.0060.096±0.025
Lanzhou ND0.116±0.0270.009±0.0040.126±0.028
Chongqing ND0.083±0.043ND0.083±0.043
Wuhan ND0.122±0.0500.017±0.0070.139±0.048
Shijiazhuang ND 1.507±1.4190.125±0.122 1.632±1.541
Guangzhou ND0.094±0.0030.008±0.0020.103±0.005
Nanjing0.029±0.0510.861±1.1080.073±0.0810.964±1.163 Salad oil (SO)
Harbin ND0.091±0.0210.007±0.0020.097±0.020
Lanzhou ND0.077±0.0150.007±0.0010.084±0.014
Chongqing ND0.472±0.6890.060±0.090.532±0.778
Shijiazhuang ND0.200±0.070.028±0.0020.228±0.072
Guangzhou ND0.116±0.0080.017±0.0030.133±0.058
Nanjing ND0.497±0.1810.046±0.0200.542±0.199 Corn oil (CO)
Harbin ND0.120±0.0420.032±0.0220.152±0.063
Lanzhou ND0.149±0.0760.041±0.0100.190±0.085
Chongqing ND 1.720±0.0170.212±0.011 1.932±0.072
Wuhan ND0.664±0.9360.098±0.1050.762±1.040
Shijiazhuang0.020±0.008 1.315±1.2370.173±0.129 1.508±1.339
Guangzhou ND0.108±0.0030.021±0.0020.129±0.031
Nanjing0.010±0.0080.852±0.6910.177±0.039 1.039±0.722 Lard (L)
Harbin0.064±0.009 1.849±0.2580.076±0.017 1.989±0.279
Lanzhou0.060±0.021 1.536±0.1650.075±0.022 1.671±0.196
Chongqing0.030±0.0170.573±0.4290.019±0.0140.622±0.460
Wuhan0.010±0.0060.126±0.0770.005±0.0040.141±0.086
Shijiazhuang0.098±0.0850.942±0.4370.023±0.003 1.063±0.507
Guangzhou0.107±0.037 2.037±0.3390.084±0.016 2.227±0.391
Nanjing0.069±0.030.953±0.2370.021±0.019 1.043±0.248 Palm oil (PO)
Harbin ND 1.562±0.0320.056±0.002 1.617±0.033
Lanzhou ND 1.459±0.3340.039±0.012 1.498±0.341
Chongqing ND0.534±0.7630.022±0.0340.556±0.797
Wuhan ND0.098±0.0130.005±0.0010.103±0.019
Shijiazhuang0.250±0.0390.461±0.0200.030±0.0030.741±0.062
Guangzhou ND0.854±1.1840.032±0.0550.886±1.239
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634Huang et al.Food Sci. Biotechnol.
of oil was significantly (p <0.05) higher than for other Chongqing oils.Generally speaking, lard contained more TFAs, mainly due to techniques of manufacture.
TFA Exposure assessment for edible oils in China Crystal Ball was used for a complete assessment of EDI values of total TFAs in Chinese edible oils.
Probability distribution of total TFA contents in Chinese edible oils A probability distribution of Cf values for TFAs was determined for evaluation of the daily TFAs intake. The results showed that total TFA contents in Chinese edible oils fitted a Gamma distribution with location=0.075, scale=1.340, and shape=0.437.
TFA exposure assessment for Chinese edible oils Determination of
total TFA EDI values based on edible oil consumption followed the Monte Carlo method. The results showed that PIR, ABS, and EF values fitted a constant distribution, Cf fitted a Gamma distribution,ED and AT values fitted a uniform distribution, and CDI fitted a forecast index. An estimate of daily TFAs intake is shown in Fig. 2. The mean EDI value for total TFAs in Chinese edible oils was 2.71×10?4and the median value was 1.25×10?4. EDI values at different percentiles were 2.63×10?5 (0%), 3.45×10?5 (10%), 4.30×10?5 (20%),6.08×10?5 (30%), 8.42×10?5 (40%), 1.25×10?4 (50%), 1.86×10?4 (60%),2.72×10?4 (70%), 4.12×10?4 (80%), 7.01×10?4 (90%), and 2.86×10?3(100%). Thus, EDI values for TFAs contents in Chinese edible oils were low.
Sensitivity analysis of the assumption Sensitivity analysis is used for estimation of the contribution of factors related to a forecast item on the final assessment. Here, the factors taken into consideration were the exposure concentration (Cf), the exposure duration (ED)and the average year (AT). Crystal Ball was then used for evaluation of the contribution of these factors.
Cf had the highest sensitivity for the CDI value of total TFAs in edible oils, with a ratio of 99.37%, indicating that Cf was the main factor contributing to daily intake of TFAs among Chinese consumers.The exposure duration and the average year had contribution values of 0.27 and 0.36% respectively, indicating that an increase in ED or AT values would generate a slight rise for the EDI value of total TFAs in Chinese edible oils.
TFA risk assessment for Chinese edible oils
TFA hazard identification : TFAs can enter human tissues via the normal fatty acid metabolic pathway and can cause adverse effects on the lipid metabolism, leading to physiologic effects on the human body, including both lipid and non-lipid effects (12). Lipid effects include metabolism disorders of lipid and apolipoprotein, and non-lipid effects include insulin resistance, systemic inflammation,endothelial dysfunction, and adiposity.
TFAs can increase serum LDL-C and decrease HDL-C levels (12),thereby increasing the ratio of LDL-C to HDL-C, which is associated with an increased risk of cardiovascular disease (CVD). A previous
Table 1. Continued
(unit: g/100 g of oil)
9t C16:1
trans C18:19t 12t C18:2Total trans Blended oil (BO)Harbin ND 0.101±0.0160.009±0.0020.110±0.019Lanzhou ND 0.153±0.1010.022±0.0330.175±0.134Chongqing ND 0.574±0.8410.050±0.0740.624±0.915Wuhan
0.005±0.001
0.158±0.0250.018±0.0090.181±0.031Shijiazhuang ND 1.779±1.8610.200±0.221 1.979±2.082Guangzhou ND 0.104±0.1040.010±0.0100.114±0.021Nanjing
ND
1.227±0.066
0.148±0.064
1.375±0.109
1)ND, not detected
2)
Means from different cities with a different superscript a, b, c in the same column were significantly different (p
<0.05).
Fig. 1. Comparison of TFA contents. (A) Comparison of TFA contents for different cities; (B) Comparison of TFA contents for different oil types. A univariate ANOVA and Tukey’s test were used for analysis of significant differences. Different letters or letter combinations on each bar indicate significant differences among different cities (A) or oils (B)(n =3, p <0.05).
Survey of Trans Fatty Acid in Edible Oils 635
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study (13) with 140,000 participants showed that for every 2%increase in TFAs intake, a 23% increase in the incidence of myocardial infarction and CVD death results. Additionally, an increasing amount of evidence suggests that TFAs intake can cause weight gain and fat accumulation, particularly visceral fat. On an isocaloric basis (11),weight gain caused by TFAs consumption was approximately 3-4x more than weight gain caused by saturated fatty acid consumption,and 7x more than weight gain caused by total fat consumption.Evidence from clinical research has proved an association of type 2diabetes incidence with TFAs consumption (1,4). TFAs probably interfere with cell membrane functions and there are reasons to believe that high levels of TFAs intake can affect insulin sensitivity and, consequently, increase the diabetes risk (13). Christiansen et al .(14) reported that, compared with monounsaturated fatty acids,dietary TFAs intake caused a significantly elevated postprandial insulin response.
The main factors that cause higher TFAs levels in edible oils are: 1)edible oil refining, 2) hydrogenation of vegetable oils, and 3)inappropriate cooking methods. A number of substances, such as free fatty acids, phospholipids, carbohydrates, and proteins, that are present in natural vegetable oils, can cause changes in color, aroma,and taste of oils, which restrict oil applications and reduce product shelf-life. Therefore, oils should be refined to remove these substances.
Generally speaking, oil refining includes degumming, neutralization,bleaching, and deodorization steps. Oils are usually heated to temperatures between 60 to 100o C before deodorization, then the temperature is increased to 180-270o C in a deodorization step, which leads to formation of TFAs (15). Tasan and Demirci (16) reported that TFA contents in oils increased 13.8x after refining.
Hydrogenated oil, due to a good consistency and melting in the mouth, has been frequently used in the food industry. Hydrogenation is based on reaction of unsaturated fatty acids of vegetable oil in the presence of a catalyst. High selectivity hydrogenation can cause a reduction in formation of saturated fatty acids. Therefore, a low hydrogen pressure, a moderate stirring speed, and a high temperature are often used in the hydrogenation process that, in turn, leads to formation of TFAs (15). Chinese traditional cooking methods usually include sautéing and frying. However, high temperature processes increase TFA contents in oils and foods. Therefore, original TFA contents in edible oils should be controlled to a low level.
TFA dose-response assessment in Chinese edible oils : TFA intake can affect the ratio of LDL/HDL in the human body (17) and a dose-dependent response exists between the percentage of TFA intake and the LDL/HDL ratio. Increased consumption of TFAs caused the LDL to HDL ratio to increase (16).
Hazard quotient assessment of TFAs in Chinese edible oils :Assessment of the hazard quotient (HQ) was based on the Monte Carlo method. The mean HQ value for total TFAs in Chinese edible oils was 0.14, the median was 0.07, and HQ values at different percentiles were 0.01 (0%), 0.02 (10%), 0.02 (20%), 0.03 (30%), 0.04(40%), 0.06 (50%), 0.09 (60%), 0.13 (70%), 0.21 (80%), 0.34 (90%),and 1.35 (100%) (Fig. 3). At percentiles ranging from 0% to 90%,forecast HQ values were all <1, indicating a low risk for TFAs consumption in Chinese edible oils.
Uncertainty analysis of TFA risk assessment in Chinese edible oils :Uncertainty of TFA risk assessment in Chinese edible oils was due to different factors. Differences between human populations may not have been considered. Reference RfD dosage values used for assessment should be current, but values used in this study needed to be updated. Hence, this risk assessment study of TFAs in Chinese edible oils should be considered as a reference point for current TFA distributions and as a forecast of TFA risks in Chinese edible oils.TFA contents in 165 edible oil samples from 7 cites in China were evaluated in this study. Total TFA concentrations varied from 0.075±0.011 to 2.243±0.770 g/100 g of oil with a mean content of 0.66 g/100 g of oil. Only 2 oil samples contained more than 2 g of TFA/100 g of oil. Generally speaking, lard contained more TFAs than other oils. Exposure assessment showed that the mean EDI value for total TFAs in Chinese edible oils was low at 2.71E-04. Among all factors considered in evaluation of EDI values of total TFAs in edible
oils, the exposure concentration (Cf) had the strongest contribution.
Fig. 3.
HQ forecast of total TFAs in Chinese edible oils
Fig. 2. EDI forecast of total TFAs in Chinese edible oils
636Huang et al.
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In addition, risk assessment demonstrated that there was a low risk for TFA consumption in Chinese edible oils.
Acknowledgments Financial support was provided by the National Key Technology R&D Program of China (Grant No.2014BAD04B03),the National Basic Research Program of China (973 program) (No:2012CB720805), and the Program for New Century Excellent Talents in University (NCET-12-0749).
Disclosure The authors declare no conflict of interest.
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高级财务会计习题答案
高级财务会计习题答案 Prepared on 22 November 2020
《高级财务会计》习题答案 第一章非货币资产交换 1、2007年5月，A公司以其一直用于出租的一幢房屋换入B公司生产的办公家具准备作为办公设备使用，B公司则换入的房屋继续出租。交换前A公司对该房屋采用成本模式进行后续计量，该房屋的原始成本为500 000元，累计已提折旧180 000元，公允价值为400 000元，没有计提减值准备；B公司换入房屋后继续采用成本模式进行计量。B公司办公家具账面价值为280 000元，公允价值与计税价格均为300 000元，适用的增值税税率为17%，B公司另外支付A公司49 000元的补价。假设交换不涉及其他的相关税费。 要求：分别编制A公司和B公司与该资产交换相关的会计分录。 A公司的会计处理： 49 000/400 000=%，所以交换属于非货币资产交换。 换入设备的入账价值=400 000-（300 000×17%）-49 000=300 000元 换出资产应确认的损益=400 000-320 000=80 000元 借：固定资产清理 320 000 累计折旧 180 000 贷：投资性房地产 500 000 借：固定资产——办公设备 300 000 银行存款 49 000 应交税金—增值税（进项） 51 000 贷：固定资产清理 320 000
其他业务收入（投资性房地产收益） 80 000 B公司的会计处理 换入设备的入账价值=300 000+300 000×17%+49 000=400 000元 换出资产应确认的损益=300 000-280 000=20 000元 借：投资性房地产 400 000 贷：主营业务收入 300 000 应交税金——增值税（销项） 51 000 银行存款 49 000 借：主营业务成本 280 000 贷：库存商品 280 000 2、2007年9月，X公司生产经营出现现金短缺，为扭转财务困境，遂决定将其正在建造的一幢办公楼及购买的办公设备与Y公司的一项专利技术及其对Z公司的一项长期股权投资进行交换。截止交换日，X公司办公楼的建设成本为900 000元。办公设备的账面价值为600 000元，公允价值为620 000元；Y公司的专利技术的账面价值为400 000元，长期股前投资的账面价值为600 000元。由于正在建造的办公楼的完工程度难以合理确定，Y公司的专利技术为新开发的前沿技术，Z公司是非上市公司，因而X公司在建的办公楼、Y公司的专利技术和对Z公司的长期股权投资这三项资产的公允价值均不能可靠计量。Y公司另支付X公司300 000元补价。假设该资产交换不涉及相关税费。 要求：分别编制X公司和Y公司与该资产交换相关的会计分录。 X公司的会计处理： 因为公允价值均不能可靠计量，所以采用账面价值计量换入资产。
Unit 9 How to Grow Old 课文翻译
Unit 9 How to Grow Old Bertrand A. Russell 1. In spite of the title, this article will really be on how not to grow old, which, at my time of life, is a much more important subject. My first advice would be, to choose your ancestors carefully. Although both my parents died young, I have done well in this respect as regards my other ancestors. My maternal grandfather, it is true, was cut off in the flower of his youth at the age of sixty-seven, but my other three grandparents all lived to be over eighty. Of remoter ancestors I can only discover one who did not live to a great age, and he died of a disease which is now rare, namely, having his head cut off. A great-grandmother of mine, who was a friend of Gibbon, lived to the age of ninety-two, and to her last day remained a terror to all her descendants. My maternal grandmother, after having nine children who survived, one who died in infancy, and many miscarriages, as soon as she became a widow devoted herself to women’s higher education. She was one of the founders of Girton College, and worked hard at opening the medical profession to women. She used to relate how she met in Italy an elderly gentleman who was looking very sad. She inquired the cause of his melancholy and he said that he had just parted fro m his two grandchildren. “Good gracious,” she exclaimed, “I have seventy-two grandchildren, and if I were sad each time I parted from one of them, I should have a dismal existence!” “Madre snaturale,” he replied. But speaking as one of the seventy-two, I prefer her recipe. After the age of eighty she found she had some difficulty in getting to sleep, so she habitually spent the hours from midnight to 3 a.m. in reading popular science. I do not believe that she ever had time to notice that she was growing old. This, I think, is the proper recipe for remaining young. If you have wide and keen interests and activities in which you can still be effective, you will have no reason to think about the merely statistical fact of the number of years you have already lived, still less of the probable brevity of your future. 2. As regards health, I have nothing useful to say since I have little experience of illness. I eat and drink whatever I like, and sleep when I cannot keep awake. I never do anything whatever on the ground that it is good for health, though in actual fact the things I like doing are mostly wholesome. 3. Psychologically there are two dangers to be guarded against in old age. One of these is undue absorption in the past. It does not do to live in memories, in regrets for the good old days, or in sadness about friends who are dead. One’s thoughts must be directed to
化工热力学答案课后总习题答案详解
化工热力学答案_课后总习题答案详解 第二章习题解答 一、问答题： 2-1为什么要研究流体的pVT 关系？ 【参考答案】：流体p-V-T 关系是化工热力学的基石，是化工过程开发和设计、安全操作和科学研究必不可少的基础数据。（1）流体的PVT 关系可以直接用于设计。（2）利用可测的热力学性质（T ，P ，V 等）计算不可测的热力学性质（H ，S ，G ，等）。只要有了p-V-T 关系加上理想气体的id p C ，可以解决化工热力学的大多数问题。 2-2在p -V 图上指出超临界萃取技术所处的区域，以及该区域的特征；同时指出其它重要的点、线、面以及它们的特征。 【参考答案】：1）超临界流体区的特征是：T >T c 、p >p c 。 2）临界点C 的数学特征： 3）饱和液相线是不同压力下产生第一个气泡的那个点的连线； 4）饱和汽相线是不同压力下产生第一个液滴点（或露点）那个点的连线。 5）过冷液体区的特征：给定压力下液体的温度低于该压力下的泡点温度。 6）过热蒸气区的特征：给定压力下蒸气的温度高于该压力下的露点温度。 7）汽液共存区：在此区域温度压力保持不变，只有体积在变化。 2-3 要满足什么条件，气体才能液化？ 【参考答案】：气体只有在低于T c 条件下才能被液化。 2-4 不同气体在相同温度压力下，偏离理想气体的程度是否相同？你认为哪些是决定偏离理想气体程度的最本质因素？ 【参考答案】：不同。真实气体偏离理想气体程度不仅与T 、p 有关，而且与每个气体的临界特性有 ()() () () 点在点在C V P C V P T T 00 2 2 ==?? ?
关，即最本质的因素是对比温度、对比压力以及偏心因子r T ，r P 和ω。 2-5 偏心因子的概念是什么？为什么要提出这个概念？它可以直接测量吗？ 【参考答案】：偏心因子ω为两个分子间的相互作用力偏离分子中心之间的作用力的程度。其物理意义为：一般流体与球形非极性简单流体（氩，氪、氙）在形状和极性方面的偏心度。为了提高计算复杂分子压缩因子的准确度。 偏心因子不可以直接测量。偏心因子ω的定义为：000.1)p lg(7.0T s r r --==ω ， ω由测定的对比温度为0.7时的对比饱和压力的数据计算而得，并不能直接测量。 2-6 什么是状态方程的普遍化方法？普遍化方法有哪些类型？ 【参考答案】：所谓状态方程的普遍化方法是指方程中不含有物性常数a ，b ，而是以对比参数作为独立变量；普遍化状态方程可用于任何流体、任意条件下的PVT 性质的计算。普遍化方法有两种类型：（1）以压缩因子的多项式表示的普遍化关系式 (普遍化压缩因子图法)；（2）以两项virial 方程表示的普遍化第二virial 系数关系式(普遍化virial 系数法) 2-7简述三参数对应状态原理与两参数对应状态原理的区别。 【参考答案】：三参数对应状态原理与两参数对应状态原理的区别在于为了提高对比态原理的精度，引入了第三参数如偏心因子ω。三参数对应态原理为：在相同的 r T 和r p 下，具有相同ω值的所有 流体具有相同的压缩因子Z ，因此它们偏离理想气体的程度相同，即),P ,T (f Z r r ω=。而两参数对应状态原理为：在相同对比温度r T 、对比压力 r p 下，不同气体的对比摩尔体积r V （或压缩因子z ） 是近似相等的，即(,) r r Z T P =。三参数对应状态原理比两参数对应状态原理精度高得多。 2-8总结纯气体和纯液体pVT 计算的异同。 【参考答案】： 由于范德华方程（vdW 方程）最 大突破在于能同时计算汽、液两相性质，因此，理论上讲，采用基于vdW 方程的立方型状态方程能同时将纯气体和纯液体的性质计算出来（最小值是饱和液体摩尔体积、最大值是饱和气体摩尔体积），但事实上计算的纯气体性质误差较小，而纯液体的误差较大。因此，液体的p-V-T 关系往往采用专门计算液体体积的公式计算，如修正Rackett 方程，它与立方型状态方程相比，既简单精度又高。 2-9如何理解混合规则？为什么要提出这个概念？有哪些类型的混合规则？ 【参考答案】：对于混合气体，只要把混合物看成一个虚拟的纯物质，算出虚拟的特征参数，如Tr ，
英语单词变复数规则
英语单词变复数规则 1.1 名词复数的规则变化 1.一般情况加 -s清辅音后读/s/ map-maps 浊辅音和元音后读 /z/ bag-bags /car-cars 2. 以s, sh, ch, x等结尾加 -es 读 /iz/ bus-buses/ watch-watches 3. 以ce, se, ze,等结尾加 -s 读 /iz/ license-licenses 4. 以辅音字母+y结尾变y 为i再加es 读 /z/ baby---babies 1.2 其它名词复数的规则变化 1）以y结尾的专有名词，或元音字母+y 结尾的名词变复数时，直接加s变复数。例如：two Marys the Henrys monkey---monkeys holiday---holidays 2）以o 结尾的名词，变复数时： a. 加s，如：photo---photos piano---pianos radio---radios zoo---zoos； b. 加es，如：potato--potatoes tomato--tomatoes c. 上述a和b两种方法均可，如zero---zeros / zeroes。 3）以f或fe 结尾的名词变复数时： a. 加s，如：belief---beliefs roof---roofs safe---safes gulf---gulfs； b. 去f,fe 加ves，如：half---halves knife---knives leaf---leaves wolf---wolves wife---wives life---lives thief---thieves； c. 上述a和b两种方法均可，如handkerchief: handkerchiefs / handkerchieves。 1.3 名词复数的不规则变化 1）child---children foot---feet tooth---teeth mouse---mice man---men woman---women 注意：由一个词加man 或woman构成的合成词，其复数形式也是-men 和-women，如an Englishman，two Englishmen。但German不是合成词，故复数形式为Germans；Bowman是姓，其复数是the Bowmans。 2）单复同形，如deer，sheep，fish，Chinese，Japanese ，li，jin，yuan，two li，three mu，four jin等。但除人民币的元、角、分外，美元、英镑、法郎等都有复数形式。如：a dollar, two dollars; a meter, two meters。 3）集体名词，以单数形式出现，但实为复数。例如： people police cattle 等本身就是复数，不能说a people，a police，a cattle，但可以说a person，a policeman，a head of cattle, the English，the British，the French，the Chinese，the Japanese，the Swiss 等名词，表示国民总称时，作复数用，如The Chinese are industries and brave.中国人民是勤劳勇敢的。 4）以s结尾，仍为单数的名词，如： a. maths，politics，physics等学科名词，一般是不可数名词，为单数。
财务会计理论答案
1、请解释为什么在非理想环境下,当计算期望现值时,无须进行估计?请解释为什么在非理 想环境下，必须在相关和可靠之间进行权衡？在你的答案中，请定义这两个术语。 P25—8 在非理想环境下，确定一整套的自然事件及其相关的现金流是非常困难的，因为有那么多的事件会发生，他们将影响未来事件的实现并导致相应的现金流。即使能够确定一整套合理的事件组合，仍然会存在困难，因为可观察的事件发生的概率我们也无法获得。这些概率必须要进行客观的估计，但是这些就会产生偏差的可靠性问题和准确度缺失问题。此外，并不一定能给出一个固定的利率。虽然期望现值仍然可以计算，但是它是一个估计值，因为现金流，概率和利率都是估计的。 P25—10 相关信息是给投资者提供关于一家企业未来经济预期的信息。更具体的讲，相关信息是帮助投资者来估计一项资产的未来现金收入或者是一项债务的未来现金支出，可靠信息是精确和无偏的信息。 当条件为不理想环境时，相关信息就要求估计可能的自然事件及其概率，这些估计在以后回顾起来可能就是不正确的，因此就会成为前期准备中的偏差，因此相关信息就好像是不可靠的。 反过来，可靠信息，例如资本资产的历史成本或者是债务的票面价值，就会失去了相关性，因为它没有包含对未来收入或者支出的预测。在资产的获得或者带息债务产生的时候，历史成本可能是具有一些相关性的，但是资产的价格和利率是时刻变化的，因此，通常情况下可靠的信息蕴含了较少的企业未来经济预期的信息，因为没有预测未来的收入和支出。 因此，一个想保留更多相关性的会计就需要处理更多更大量的自然事件组合以及与之相关的概率。然而，这意味着将会较少的可靠性。因此，关于会计信息的这两个属性必须进行权衡，因为他们是此消彼长的关系。 2、解释财务报表的信息观，它依赖于会计的历史成本基础吗？ P95—1 信息观认为财务报告是向投资者传达有用信息一种途径，然后，投资就需要决定是否使用这一信息来形成他们自己对未来盈利能力和股票收益的后验概率。 信息观与会计的历史成本基础是一致的，但是不依赖于它。基于理论和经验的证据表明历史成本基础的财务报告向投资者提供了有用的信息。但是，没有特别的理由来解释为什么这些信息必须由历史成本基础来提供。RRA（储备确认会计）信息不是历史成本基础的，也不是说明事项和管理层讨论分析（MD&A）的大多数信息。这个信息的本质，就像上面提到的一样，是指投资者在形成他们自己对未来业绩的估计的时候，是被假设成不仅仅使用会计信息，还会使用其它的相关信息，而会计是不会为他们做这些的。披露的特别形式并不重要，重要的仅仅是信息被公开。因此，在有附加信息来补充财务报告的时候，信息观可以用于证明以历史成本作为财务报告的基础是合适的。进而根据有效市场理论就可以保证，通常，投资者是能够合适地理解这一信息。 3、为什么决策有用性建议，在恰当的财务报表中包含更多的价值相关信息，而有效资本市 场理论暗示，报表附注以及其他披露方式同样有效？当会计人员采用计量观时会对相关性、可靠性以及财务报表信息的决策有用性产生什么影响？
Thechaser追逐者中英对照
The Chaser John Collier Alan Auste n, as n ervous as a kitte n, went up certa in dark and creaky stairs in the n eighborhood of Pell Street , and peered about for a long time on the dim landing before he found the n ame he wan ted writte n obscurely on one of the doors. He pushed ope n this door, as he had bee n told to do, and found himself in a tiny room, which contained no furn iture but a pla in kitche n table, a rock in g-chair, and an ordinary chair. On one of the dirty buff-colored walls were a couple of shelves, containing in all perhaps a doze n bottles and jars. An old man sat in the rock in g-chair, read ing a n ewspaper. Ala n, without a word, handed him the card he had been given. 人Sit down, Mr. Austen, said the old man very politely. 人I am glad to make your acqua intance. 人Is it true, asked Alan, 人that you have a certain mixture that has ! er ! quite extraordinary effects? 人My dear sir, replied the old man, 人my stock in trade is not very large ! I don …t deal in laxatives and teething mixtures ! but such as it is, it is varied. I think nothing I sell has effects which could be precisely described as ordin ary. 人Well, the fact is ! began Alan. 人Here, for example, interrupted the old man, reaching for a bottle from the shelf. 人Here is a liquid as colorless as water, almost tasteless, quite imperceptible in coffee, wine, or any other beverage. It is also quite imperceptible to any known method of autopsy. 人Do you mean it is a poison? cried Alan, very much horrified. 人Call it a glove-cleaner if you like, said the old man indifferently. 人Maybe it will clean gloves. I have never tried. One might call it a life-cleaner. Lives need cleaning sometimes. 人I want nothing of that sort, said Alan. 人Probably it is just as well, said the old man. 人Do you know the price of this? For one teaspoonful, which is sufficient, I ask five thousa nd dollars. Never less. Not a penny less. 人I hope all your mixtures are not as expensive, said Alan apprehe nsively. 人Oh dear, no, said the old man. 人It would be no good charg ing that sort of price for a love poti on, for example. Young people who n eed a love poti on very seldom have five thousa nd dollars. Otherwise they would not n eed a love poti on. 人I am glad to hear that, said Alan. 人I look at it like this, said the old man. 人Please a customer with one article, and he will come back whe n he n eeds another. Even if it is more costly. He will save up for it, if n ecessary. 人So, said Alan, 人you really do sell love potions? 人If I did not sell love potions, said the old man, reaching for another bottle, 人I should not have mentioned the other matter to you. It is only whe n one is in a positi on to oblige that one can afford to be so con fide ntial. 人And these potions, said Alan. 人They are not just ! just ! er ! 人Oh, no, said the old man. 人Their effects are permanent, and exte nd far bey ond casual impulse. But they in clude it. Boun tifully, in siste ntly. Everlast in gly. 人Dear me! said Alan, attempting a look of scientific detachme nt. "How very in teresti ng! 人But consider the spiritual side, said the old man.
《化工热力学》详细课后习题答案陈新志
2 习题 第1章 绪言 一、是否题 1. 孤立体系的热力学能和熵都是一定值。( 错。 和 ，如一 体积等于2V 的绝热刚性容器，被一理想的隔板一分为二，左侧状态是T ，P 的理想气体，右侧是T 温度 的真空。当隔板抽去后，由于Q ＝W ＝0， ， ，，故体系将在T ，2V ，0.5P 状态下 达到平衡， ， ， ） 2. 封闭体系的体积为一常数。（错） 3. 封闭体系中有两个相 。在尚未达到平衡时，两个相都是均相敞开体系；达到平衡时，则 两个相都等价于均相封闭体系。（对） 4. 理想气体的焓和热容仅是温度的函数。（对） 5. 理想气体的熵和吉氏函数仅是温度的函数。（错。还与压力或摩尔体积有关。） 6. 要确定物质在单相区的状态需要指定两个强度性质，但是状态方程 P=P (T ，V )的自变量中只有一个强度 性质，所以，这与相律有矛盾。（错。V 也是强度性质） 7. 封闭体系的1mol 气体进行了某一过程，其体积总是变化着的，但是初态和终态的体积相等，初态和终 态的温度分别为T 1和T 2，则该过程的 ；同样，对于初、终态压力相等的过程有 。（对。状态函数的变化仅决定于初、终态与途径无关。） 8. 描述封闭体系中理想气体绝热可逆途径的方程是（其中 ），而一位学生认 为这是状态函数间的关系，与途径无关，所以不需要可逆的条件。(错。) 9. 自变量与独立变量是一致的，从属变量与函数是一致的。（错。有时可能不一致） 10. 自变量与独立变量是不可能相同的。（错。有时可以一致） 三、填空题 1. 状态函数的特点是：状态函数的变化与途径无关，仅决定于初、终态 。 2. 单相区的纯物质和定组成混合物的自由度数目分别是 2 和 2 。 3. 封闭体系中，温度是T 的1mol 理想气体从(P ，V )等温可逆地膨胀到(P ，V )，则所做的功为 i i f f (以V 表示)或 (以P 表示)。 4. 封闭体系中的1mol 理想气体(已知 )，按下列途径由T 1、P 1和V 1可逆地变化至P ，则
英语名词单复数用法大全
英语名词单复数用法大全 一、规则名词的复数形式：名词的复数形式，一般在单数形式后面加-s 或 -es。现将构成方法与读音规则列表如下： 1、一般情况在词尾加 -s：map-maps, sea-seas, girl-girls, day-days 2、以 s, x, ch, sh 结尾的名词后加 -es：class-classes, box-boxes, watch-watches, dish-dishes 3、以 -f 或 -fe 结尾的词变 -f 和 -fe 为 v再加 -es： l eaf-leaves, thief-thieves, knife-knives, loaf-loaves, wife-wives ；加 -s： belief-beliefs, chief-chiefs, proof-proofs, roof-roofs, gulf-gulfs 4 、以辅音字母加y 结尾的名词，变y 为 i 加 -es ： party-parties, family-families, story-stories, city-cities 5 、以音辅字母加y 结尾的名词，或专有名词以y 结尾的，加-s toy-toys, boy-boys, day-days, ray-rays, Henry-Henrys 6、以辅音字母加 -o 结尾的名词一般加 -es： hero-heroes, Negro-Negroes, potato-potatoes, tomato-tomatoes；不少外来词加 -s： piano-pianos, photo-photos, auto-autos, kilo-kilos, solo-solos 两者皆可： zero-zeros/zeroes, volcano-volcanoes/ volcanos 7 、以元音字母加-o 结尾的名词加-s： radio-radios, bamboo-bamboos, zoo-zoos 8 、以 -th 结尾的名词加-s： truth-truths, mouth-mouths, month-months, path-paths 二、不规则名词复数： 英语里有些名词的复数形式是不规则的，现归纳如下： 1、改变名词中的元音字母或其他形式： man-men, woman-women, foot-feet, goose-geese, mouse-mice 2、单复数相同：sheep, deer, series, means, works, fish, species li, yuan, jin, 3、只有复数形式：ashes, trousers, clothes, thanks, goods, glasses, compasses, contents 4、一些集体名词总是用作复数：people, police, cattle, staff 5、部分集体名词既可以作单数（整体）也可以作复数（成员）： audience, class, family, crowd, couple, group, committee, government, population, crew, team, public, enemy, party 6、复数形式表示特别含义：customs(海关 ), forces( 军队 ), times( 时代 ), spirits( 情绪 ), drinks( 饮料), sands(沙滩 ), papers(文件报纸 ), manners(礼貌 ), looks( 外表 ), brains( 头脑智力 ), greens(青菜), ruins( 废墟 ) 7、表示“某国人”加 -s： Americans, Australians, Germans, Greeks, Swedes, Europeans；单复 数同形 Swiss, Portuguese, Chinese, Japanese；以 -man 或-woman 结尾的改为 men,-women，Englishmen, Frenchwomen 8、合成名词将主体名词变为复数：sons-in-law, lookers-on, passers-by, story-tellers, boy friends ； grown-ups, housewives, stopwatches ；将两部分变为复无主体名词时将最后一部分变为复数： 数： women singers, men servants
Unit7TheChaser课文翻译综合教程三
Unit 7 The Chaser John Henry Collier 1 Alan Austen, as nervous as a kitten, went up certain dark and creaky stairs in the neighborhood of Pell Street, and peered about for a long time on the dim hallway before he found the name he wanted written obscurely on one of the doors. 2 He pushed open this door, as he had been told to do, and found himself in a tiny room, which contained no furniture but a plain kitchen table, a rocking-chair, and an ordinary chair. On one of the dirty buff-coloured walls were a couple of shelves, containing in all perhaps a dozen bottles and jars. 3 An old man sat in the rocking-chair, reading a newspaper. Alan, without a word, handed him the card he had been given. “Sit down, Mr. Austen,” said the old man very politely. “I am glad to make your acquaintance.” 4 “Is it true,” asked Alan, “that you have a certain mixture that has … er … quite extraordinary effects?” 5 “My dear sir,” replied the old man, “my sto ck in trade is not very large — I don’t deal in laxatives and teething mixtures —but such as it is, it is varied. I think nothing I sell has effects which could be precisely described as ordinary.” 6 “Well, the fact is …” began Alan. 7 “Here, for example,” interrupted the old man, reaching for a bottle from the shelf. “Here is a liquid as colourless as water, almost tasteless, quite imperceptible in coffee, wine, or any other beverage. It is also quite imperceptible to any known method of autopsy.” 8 “Do you mean it is a poison?” cried Alan, very much horrified. 9 “Call it a glove-cleaner if you like,” said the old man indifferently. “Maybe it will clean gloves. I have never tried. One might call it a life-cleaner. Lives need cleaning sometimes.” 10 “I want nothing of that sort,” said Alan. 11 “Probably it is just as well,” said the old man. “Do you know the price of this? For one teaspoonful, which is sufficient, I ask five thousand dollars. Never less. Not a penny less.” 12 “I hope all your mixtures are not as expensive,” said Alan apprehensively.
化工热力学复习题(附答案)
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英语单词变复数
一般情况加-s 1.清辅音后读/s/; map-maps 2.浊辅音和元音后bag-bags 读/z/; car-cars 以s,sh,ch, x等结尾的词加-es 读/iz/ bus-buses ，watch-watches 以ce,se,ze, (d)ge等结尾的词加-s 读/iz/ license-licenses 以辅音字母+y 变y 为i 结尾的词再加es 读/z/ baby---babies 名词复数的不规则变化 1）child---children foot---feet tooth---teeth mouse---mice man---men woman---women 注意：与man 和woman构成的合成词，其复数形式也是-men 和-women。 如：an Englishman，two Englishmen. 但German不是合成词，故复数形式为Germans；Bowman是姓，其复数是the Bowmans。 2）单复同形如： deer，sheep，fish，Chinese，Japanese li，jin，yuan，two li，three mu，four jin 但除人民币元、角、分外，美元、英镑、法郎等都有复数形式。如: a dollar, two dollars; a meter, two meters 3）集体名词，以单数形式出现，但实为复数。 如：people police cattle 等本身就是复数，不能说a people，a police，a cattle，但可以说a person，a policeman，a head of cattle,the English，the British，the French，the Chinese，the Japanese，the Swiss 等名词，表示国民总称时，作复数用。如：The Chinese are industries and brave. 中国人民是勤劳勇敢的。 4）以s结尾，仍为单数的名词，如：a. maths，politics，physics等学科名词，为不可数名词，是单数。 b. news 是不可数名词。 c. the United States，the United Nations 应视为单数。 The United Nations was organized in 1945. 联合国是1945年组建起来的。 d. 以复数形式出现的书名，剧名，报纸，杂志名，也可视为单数。 "The Arabian Nights" is a very interesting story-book. <<一千零一夜>>是一本非常有趣的故事书。 5) 表示由两部分构成的东西，如：glasses (眼镜) trousers, clothes 若表达具体数目，要借助数量词pair(对，双); suit(套); a pair of glasses; two pairs of trousers 6）另外还有一些名词，其复数形式有时可表示特别意思，如：goods货物，waters 水域，fishes（各种）鱼