To rapidly determine the pollution extent of wastewater, the calibration models were established for deter-mination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater by partial least squares and nea...To rapidly determine the pollution extent of wastewater, the calibration models were established for deter-mination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater by partial least squares and near infrared spectrometry of 120 samples. Spectral data preprocessing and outliers’ diagnosis were also discussed. Correlation coefficients of the models were 0.9542 and 0.9652, and the root mean square error of prediction (RMSEP) were 25.24 mg?L-1 and 12.13 mg?L-1 in the predicted range of 28.40~528.0 mg?L-1 and 16.0~305.2 mg?L-1 for Chemical Oxygen Demand and Biological Oxygen Demand, respectively. By statistical significance test, the results of determination were compared with those of stan-dard methods with no significant difference at 0.05 level. The method has been applied to simultaneous de-termination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater with satisfactory results.展开更多
As a kind of traditional Chinese medicinal materials coptis chinensis has a lot of medicinal value and closely related to human health, Widely used in clinical or disease prevention and treatment. So the quality of me...As a kind of traditional Chinese medicinal materials coptis chinensis has a lot of medicinal value and closely related to human health, Widely used in clinical or disease prevention and treatment. So the quality of medicinal coptis chinensis rapid determination is very important. Calibration model for determination of Coptis chinensis’ quality was built by partial least squares and near infrared spectroscopy, and the method of spectral pretreatment was discussed. Berberine and moisture content were used as evaluation index of Coptis chinensis’ quality according to traditional Chinese medicine standard in this experiment. The first derivative and vector normalization were adopted for the spectral preprocessing. The performance of the final model was evaluated according to root mean squares error of cross-validation (RMSECV), root mean square error of prediction (RMSEP) and correlation coefficient (R). According to the model of calibration set, the R values were 0.9298 and 0.8898, RMSECV were 0.239% and 0.302%. The R values of prediction set were 0.9347 and 0.9146, RMSEP were 0.104% and 0.330%, and prediction results were accurate and reliable. This method could be applied in rapid analysis of Coptis chinensis. The method was suitable for production fields and research fields, and had a wide application prospect.展开更多
In pH 4.8 Britton-Robinson (B-R) buffer solution, Mercaptopurine (MP) could react with Cu(II) to form stable chelate compound, a new Resonance Rayleigh scattering (RRS) spectrum generated and enhanced for the binary s...In pH 4.8 Britton-Robinson (B-R) buffer solution, Mercaptopurine (MP) could react with Cu(II) to form stable chelate compound, a new Resonance Rayleigh scattering (RRS) spectrum generated and enhanced for the binary system which the highest peak located at 453 nm as detection wavelength. But the RRS spectra could be quenched after adding her- ring milt DNA (hsDNA), salmon milt DNA (sDNA) and calf thymus DNA (ctDNA) into the binary system, respect- tively. And the weakened degree of spectra was directly proportional to the concentration of DNA. The reaction product of three nucleic acid system have identical spectral features, their range of linearity for the relation of spectral intensity with concentration respectively are 0.05 - 0.9 μg.mL-1 for hsDNA, 0.1 - 0.9 μg.mL-1 for sDNA and 0.3 - 0.9 μg.mL-1 for ctDNA;their detection limit respectively are 5 ng.mL-1for hsDNA, 6 ng.mL-1for sDNA, 6 ng?mL-1 for ctDNA. So a new method for determination of DNA was developed and successfully applied to determine the content of the DNA in artificial synthetized samples. At the same time the spectral features of absorption spectra and RRS spectra of the three reaction system, and the eligible reaction conditions and influencing factors were investigated in this paper.展开更多
Since China＇s accession to the WTO in 2001, China has been on a steep learning curve in terms of engaging in outward direct investment, and state-owned enterprises （SOEs） have played a predominant role in this driv...Since China＇s accession to the WTO in 2001, China has been on a steep learning curve in terms of engaging in outward direct investment, and state-owned enterprises （SOEs） have played a predominant role in this drive. We argue that investment overseas by SOEs is a double-edged sword as far as its impact on domestic reform is concerned. Investing overseas offers opportunities to deepen structural reform in China, but such investment could also strengthen the monopoly position of some SOEs, which is inconsistent with the objective of domestic reform. Therefore, it is important for China to deepen domestic reform with respect to competition, ownership and regulations, to maximize the benefits from investing overseas＇. The present paper also discusses how building market-compatible institutions will resuh in increased innovation. This provides opportunities for Chinese firms to effectively catch up with the advanced technologies to remain competitive in overseas markets.展开更多
Information and communication technology plays an important role in human life and social production.The existing literature has mainly studied the economic impact of such technology in developed countries;the use of ...Information and communication technology plays an important role in human life and social production.The existing literature has mainly studied the economic impact of such technology in developed countries;the use of broadband in developing countries has been overlooked.This paper fills the gap by examining a broadband development program in China.Difference-in-difference estimates show that the deployment of high-quality broadband promoted regional employment in the skilled service sector.The effect was larger in cities with a greater number of educated residents and cities in the west of China.We also found that broadband development stimulated firm creation and innovation.These findings imply that broadband promotes innovation and provides new impetus to the economic transition of emerging markets.展开更多
An efficient semi-synthetic method was developed to construct docetaxel 1 by using N,N-di-Boc protected lin- ear isoserine derivative 5 as the side chain source, in which, bulky protecting group on the nitrogen atom b...An efficient semi-synthetic method was developed to construct docetaxel 1 by using N,N-di-Boc protected lin- ear isoserine derivative 5 as the side chain source, in which, bulky protecting group on the nitrogen atom blocked C-2＇ position and prohibited unavoidable racemization in previous studies.展开更多
Economic policy uncertainty has prominent effects on investment and output.Using unique transaction-level data in China,this paper explores the impact of economic policy uncertainty on land transaction premiums in Chi...Economic policy uncertainty has prominent effects on investment and output.Using unique transaction-level data in China,this paper explores the impact of economic policy uncertainty on land transaction premiums in China.On average,a 1%increase in the policy uncertainty level reduces land transaction premiums by 3.907 percentage points.The impact of policy uncertainty is more profound for firms with tighter financial constraints and land located in cities with lower rent-to-price ratios.The influence of policy uncertainty becomes weaker after the anti-corruption campaign in China,especially in provinces scrutinised by the central inspection teams,implying that improvements in the political environment alleviates the impact of policy uncertainty.展开更多
文摘To rapidly determine the pollution extent of wastewater, the calibration models were established for deter-mination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater by partial least squares and near infrared spectrometry of 120 samples. Spectral data preprocessing and outliers’ diagnosis were also discussed. Correlation coefficients of the models were 0.9542 and 0.9652, and the root mean square error of prediction (RMSEP) were 25.24 mg?L-1 and 12.13 mg?L-1 in the predicted range of 28.40~528.0 mg?L-1 and 16.0~305.2 mg?L-1 for Chemical Oxygen Demand and Biological Oxygen Demand, respectively. By statistical significance test, the results of determination were compared with those of stan-dard methods with no significant difference at 0.05 level. The method has been applied to simultaneous de-termination of Chemical Oxygen Demand and Biological Oxygen Demand in wastewater with satisfactory results.
文摘As a kind of traditional Chinese medicinal materials coptis chinensis has a lot of medicinal value and closely related to human health, Widely used in clinical or disease prevention and treatment. So the quality of medicinal coptis chinensis rapid determination is very important. Calibration model for determination of Coptis chinensis’ quality was built by partial least squares and near infrared spectroscopy, and the method of spectral pretreatment was discussed. Berberine and moisture content were used as evaluation index of Coptis chinensis’ quality according to traditional Chinese medicine standard in this experiment. The first derivative and vector normalization were adopted for the spectral preprocessing. The performance of the final model was evaluated according to root mean squares error of cross-validation (RMSECV), root mean square error of prediction (RMSEP) and correlation coefficient (R). According to the model of calibration set, the R values were 0.9298 and 0.8898, RMSECV were 0.239% and 0.302%. The R values of prediction set were 0.9347 and 0.9146, RMSEP were 0.104% and 0.330%, and prediction results were accurate and reliable. This method could be applied in rapid analysis of Coptis chinensis. The method was suitable for production fields and research fields, and had a wide application prospect.
文摘In pH 4.8 Britton-Robinson (B-R) buffer solution, Mercaptopurine (MP) could react with Cu(II) to form stable chelate compound, a new Resonance Rayleigh scattering (RRS) spectrum generated and enhanced for the binary system which the highest peak located at 453 nm as detection wavelength. But the RRS spectra could be quenched after adding her- ring milt DNA (hsDNA), salmon milt DNA (sDNA) and calf thymus DNA (ctDNA) into the binary system, respect- tively. And the weakened degree of spectra was directly proportional to the concentration of DNA. The reaction product of three nucleic acid system have identical spectral features, their range of linearity for the relation of spectral intensity with concentration respectively are 0.05 - 0.9 μg.mL-1 for hsDNA, 0.1 - 0.9 μg.mL-1 for sDNA and 0.3 - 0.9 μg.mL-1 for ctDNA;their detection limit respectively are 5 ng.mL-1for hsDNA, 6 ng.mL-1for sDNA, 6 ng?mL-1 for ctDNA. So a new method for determination of DNA was developed and successfully applied to determine the content of the DNA in artificial synthetized samples. At the same time the spectral features of absorption spectra and RRS spectra of the three reaction system, and the eligible reaction conditions and influencing factors were investigated in this paper.
文摘Since China＇s accession to the WTO in 2001, China has been on a steep learning curve in terms of engaging in outward direct investment, and state-owned enterprises （SOEs） have played a predominant role in this drive. We argue that investment overseas by SOEs is a double-edged sword as far as its impact on domestic reform is concerned. Investing overseas offers opportunities to deepen structural reform in China, but such investment could also strengthen the monopoly position of some SOEs, which is inconsistent with the objective of domestic reform. Therefore, it is important for China to deepen domestic reform with respect to competition, ownership and regulations, to maximize the benefits from investing overseas＇. The present paper also discusses how building market-compatible institutions will resuh in increased innovation. This provides opportunities for Chinese firms to effectively catch up with the advanced technologies to remain competitive in overseas markets.
基金Qing Wang acknowledges the financial assistance provided by the National Natural Science Foundation of China(No.71903007).
文摘Information and communication technology plays an important role in human life and social production.The existing literature has mainly studied the economic impact of such technology in developed countries;the use of broadband in developing countries has been overlooked.This paper fills the gap by examining a broadband development program in China.Difference-in-difference estimates show that the deployment of high-quality broadband promoted regional employment in the skilled service sector.The effect was larger in cities with a greater number of educated residents and cities in the west of China.We also found that broadband development stimulated firm creation and innovation.These findings imply that broadband promotes innovation and provides new impetus to the economic transition of emerging markets.
文摘An efficient semi-synthetic method was developed to construct docetaxel 1 by using N,N-di-Boc protected lin- ear isoserine derivative 5 as the side chain source, in which, bulky protecting group on the nitrogen atom blocked C-2＇ position and prohibited unavoidable racemization in previous studies.
基金Xiaoyang Li thanks the National Natural Science Foundation of China[Grant No.72303197]for financial supportMo Liang thanks the National Natural Science Foundation of China[Grant No.71803188]for financial support+1 种基金Jidong Yang thanks the Humanities and Social Sciences Research Project of the Ministry of Education[Grant No.22YJA790076]the Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China[Grant No.23XNA011]for financial support.
文摘Economic policy uncertainty has prominent effects on investment and output.Using unique transaction-level data in China,this paper explores the impact of economic policy uncertainty on land transaction premiums in China.On average,a 1%increase in the policy uncertainty level reduces land transaction premiums by 3.907 percentage points.The impact of policy uncertainty is more profound for firms with tighter financial constraints and land located in cities with lower rent-to-price ratios.The influence of policy uncertainty becomes weaker after the anti-corruption campaign in China,especially in provinces scrutinised by the central inspection teams,implying that improvements in the political environment alleviates the impact of policy uncertainty.
