This paper presents a mathematical model for components/parts unification (CPU) policy. This model considers two components/parts that are functionally interchangeable but purchased from suppliers with different price...This paper presents a mathematical model for components/parts unification (CPU) policy. This model considers two components/parts that are functionally interchangeable but purchased from suppliers with different prices and quality characteristics. Because of the buyer's quality preference and suppliers' discount rates for bulky purchases, the model assists the procurement manager to determine how best to purchase the components/parts to meet its demand while minimizing the total acquisition costs.展开更多
[Objectives] To analyze and compare the difference in volatile components of different cultivars and different parts of Artemisia argyi by using headspace solid phase microextraction( HS-SPME) and provide scientific b...[Objectives] To analyze and compare the difference in volatile components of different cultivars and different parts of Artemisia argyi by using headspace solid phase microextraction( HS-SPME) and provide scientific basis for comprehensive development and rational utilization of Artemisia argyi. [Methods]Firstly,HS-SPME was used to extract the volatile components from the leaves,seeds,and stems of seven-tip Artemisia argyi,five-tip Artemisia argyi,and golden Artemisia argyi. Their chemical composition was analyzed by gas chromatographymass spectrometry( GC-MS),and the relative mass fraction of each component was determined by area normalization method. [Results] For the same variety of Artemisia argyi,the content of volatile components in leaves was higher than in seeds and stems except camphor,and the content of volatile components in seven-tip Artemisia argyi leaves was higher than in five-tip Artemisia argyi and golden Artemisia argyi leaves.HS-SPME-GC-MS analysis showed that eucalyptol,camphor,thujone,α-pinene,1-caryophyllene and caryophyllene oxide with higher content were detected in different parts of the different cultivars of Artemisia argyi. [Conclusions]Seven-tip Artemisia argyi leaves were the best medicinal parts of the three cultivars,followed by seven-tip Artemisia argyi seeds.展开更多
[Objectives] To analyze the volatile components in different parts of Polygala japonica Houtt. and compare the differences of these volatile components. [Methods] The volatile components in different parts of P. japon...[Objectives] To analyze the volatile components in different parts of Polygala japonica Houtt. and compare the differences of these volatile components. [Methods] The volatile components in different parts of P. japonica Houtt. were analyzed by the headspace solid-phase microextraction( HS-SPME) combined with GC-MS,and the relative percentage of each component was determined by peak area normalization. [Results] Thirty kinds of volatile components were identified from the leaves and rhizomes of P. japonica Houtt.,mainly including olefins,aromatic hydrocarbons,alkanes and esters. [Conclusions] The volatile components in different parts of P. japonica Houtt. were different,and there may be difference in the medicinal value of volatile components in different parts,thus it is required to take an overall consideration of these differences in the development and utilization of P. japonica Houtt.展开更多
Shanghai Santana cars had produced a total of 270,000 cars by the end of 1993, and undergone SKD, CKD and localization stages. The car industry will soon become a pillar industry in Shanghai. During its development, t...Shanghai Santana cars had produced a total of 270,000 cars by the end of 1993, and undergone SKD, CKD and localization stages. The car industry will soon become a pillar industry in Shanghai. During its development, the Shanghai car industry has always given special attention to localization, thus the localization rate of car parts and components has increased year by year. In 1988, Shanghai Santanacars produced 15,000 units, with 13,08 percent of展开更多
China is one of the few countries using coal as the main energy and is the world's second largest coal consumer. Researching the coal consumption is very necessary. At present,the prediction model of coal consumpt...China is one of the few countries using coal as the main energy and is the world's second largest coal consumer. Researching the coal consumption is very necessary. At present,the prediction model of coal consumption is mainly based on time series analysis of price,and it rarely considers the influence of other factors. In this paper,on the basis of demand theory,we establish the multiple impact indicators,and use principal component analysis as well as partial linear model for multiple factors to establish coal consumption model. By using this model to forecast the coal consumption in 2011,we find that the predicted value is close to actual value,which means that the model is good.展开更多
文摘This paper presents a mathematical model for components/parts unification (CPU) policy. This model considers two components/parts that are functionally interchangeable but purchased from suppliers with different prices and quality characteristics. Because of the buyer's quality preference and suppliers' discount rates for bulky purchases, the model assists the procurement manager to determine how best to purchase the components/parts to meet its demand while minimizing the total acquisition costs.
基金Supported by Natural Science Foundation of Hubei Province(2004AB242)
文摘[Objectives] To analyze and compare the difference in volatile components of different cultivars and different parts of Artemisia argyi by using headspace solid phase microextraction( HS-SPME) and provide scientific basis for comprehensive development and rational utilization of Artemisia argyi. [Methods]Firstly,HS-SPME was used to extract the volatile components from the leaves,seeds,and stems of seven-tip Artemisia argyi,five-tip Artemisia argyi,and golden Artemisia argyi. Their chemical composition was analyzed by gas chromatographymass spectrometry( GC-MS),and the relative mass fraction of each component was determined by area normalization method. [Results] For the same variety of Artemisia argyi,the content of volatile components in leaves was higher than in seeds and stems except camphor,and the content of volatile components in seven-tip Artemisia argyi leaves was higher than in five-tip Artemisia argyi and golden Artemisia argyi leaves.HS-SPME-GC-MS analysis showed that eucalyptol,camphor,thujone,α-pinene,1-caryophyllene and caryophyllene oxide with higher content were detected in different parts of the different cultivars of Artemisia argyi. [Conclusions]Seven-tip Artemisia argyi leaves were the best medicinal parts of the three cultivars,followed by seven-tip Artemisia argyi seeds.
文摘[Objectives] To analyze the volatile components in different parts of Polygala japonica Houtt. and compare the differences of these volatile components. [Methods] The volatile components in different parts of P. japonica Houtt. were analyzed by the headspace solid-phase microextraction( HS-SPME) combined with GC-MS,and the relative percentage of each component was determined by peak area normalization. [Results] Thirty kinds of volatile components were identified from the leaves and rhizomes of P. japonica Houtt.,mainly including olefins,aromatic hydrocarbons,alkanes and esters. [Conclusions] The volatile components in different parts of P. japonica Houtt. were different,and there may be difference in the medicinal value of volatile components in different parts,thus it is required to take an overall consideration of these differences in the development and utilization of P. japonica Houtt.
文摘Shanghai Santana cars had produced a total of 270,000 cars by the end of 1993, and undergone SKD, CKD and localization stages. The car industry will soon become a pillar industry in Shanghai. During its development, the Shanghai car industry has always given special attention to localization, thus the localization rate of car parts and components has increased year by year. In 1988, Shanghai Santanacars produced 15,000 units, with 13,08 percent of
文摘China is one of the few countries using coal as the main energy and is the world's second largest coal consumer. Researching the coal consumption is very necessary. At present,the prediction model of coal consumption is mainly based on time series analysis of price,and it rarely considers the influence of other factors. In this paper,on the basis of demand theory,we establish the multiple impact indicators,and use principal component analysis as well as partial linear model for multiple factors to establish coal consumption model. By using this model to forecast the coal consumption in 2011,we find that the predicted value is close to actual value,which means that the model is good.
