检索结果-南通市图书馆

Metal composition of layered double hydroxides(LDHs) regulating ClO_4^- adsorption to calcined LDHs via the memory effect and hydrogen bonding

在线全文

学校读者我要写书评

暂无评论

Journal of environmental sciences 2014年第3期26卷 493-501页

作者： Yajie Lin Qile Fang baoliang chen department of environmental science Zhejiang University zhejiang Provincial Key Laboratory of Organic Pollution Process and Control

A series of calcined carbonate layered double hydroxides （CLDHs） with various metal compositions and different M^2＋/M^3＋ ratios were prepared as adsorbents for perchlorate. Adsorption isotherms fit Langmuir model well, and the adsorption amount followed the order of MgA1-CLDHs 1〉 MgFeCLDHs 〉〉 ZnA1-CLDHs. The isotherms of MgA1-CLDHs and MgFe-CLDHs displayed a two-step shape at low and high concentration ranges and increased with an increase in the M^2＋/M^3＋ ratio from 2 to 4. The two-step isotherm was not observed for ZnA1-CLDHs, and the adsorption was minimally affected by the M^2＋/M^3＋ ratio. The LDHs, CLDHs and the reconstructed samples were characterized by X-ray diffraction, SEM, FT-IR and Raman spectra to delineate the analysis of perchlorate adsorption mechanisms. The perchlorate adsorption of MgA1-CLDHs and MgFe-CLDHs was dominated by the structural memory effect and the hydrogen bonds between the free hydroxyl groups on the reconstructed-LDHs and the oxygen atoms of the perchlorates. For ZnAI-CLDHs, the perchlorate adsorption was controlled by the structural memory effect only, as the hydroxyl groups on the hydroxide layers preferred to form strong hydrogen bonds with carbonate over perchlorate, which locked the intercalated perchlorate into a more confined nano-interlayer. Several distinct binding mechanisms of perchlorate by CLDHs with unique M^2＋ ions were proposed.

关键词： calcined layered double hydroxidesperchlorateadsorption memory effecthydrogen bonds

Improving model performance in mapping cropland soil organic matter using time-series remote sensing data

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2024年第8期23卷 2820-2841页

作者： Xianglin Zhang Jie Xue Songchao chen Zhiqing Zhuo Zheng Wang Xueyao chen Yi Xiao Zhou Shi Institute of Applied Remote Sensing and Information Technology College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China department of Land Management Zhejiang UniversityHangzhou 310058China ZJU-hangzhou Global Scientific and Technological Innovation Center Zhejiang UniversityHangzhou 311215China Institute of Digital Agriculture Zhejiang Academy of Agricultural SciencesHangzhou 310021China Key Laboratory of Spectroscopy Sensing Ministry of Agriculture and Rural AffairsHangzhou 310058China

Faced with increasing global soil degradation,spatially explicit data on cropland soil organic matter(SOM)provides crucial data for soil carbon pool accounting,cropland quality assessment and the formulation of effective management *** a spatial information prediction technique,digital soil mapping(DSM)has been widely used to spatially map soil information at different ***,the accuracy of digital SOM maps for cropland is typically lower than for other land cover types due to the inherent difficulty in precisely quantifying human *** overcome this limitation,this study systematically assessed a framework of“information extractionfeature selection-model averaging”for improving model performance in mapping cropland SOM using 462 cropland soil samples collected in Guangzhou,china in *** results showed that using the framework of dynamic information extraction,feature selection and model averaging could efficiently improve the accuracy of the final predictions(R^(2):0.48 to 0.53)without having obviously negative impacts on *** the dynamic information of the environment was an efficient way to generate covariates that are linearly and nonlinearly related to SOM,which improved the R^(2)of random forest from 0.44 to 0.48 and the R^(2)of extreme gradient boosting from 0.37to *** recursive feature selection(FRFS)is recommended when there are relatively few environmental covariates(environmental covariates(>500).The Granger-Ramanathan model averaging approach could improve the prediction accuracy and average *** the structures of initial prediction models are similar,increasing in the number of averaging models did not have significantly positive effects on the final *** the advantages of these selected strategies over information extraction,feature selection and model averaging have a great potential for high-accuracy soil mapping

关键词： cropland soil organic matter digital soil mapping machine learning feature selection model averaging

Sorption of chlorophenols onto fruit cuticles and potato periderm

在线全文

学校读者我要写书评

暂无评论

Journal of environmental sciences 2012年第4期24卷 675-681页

作者： Yungui Li Yingqing Deng baoliang chen department of environmental science Zhejiang UniversityHangzhou 310058China zhejiang Provincial Key Laboratory of Organic Pollution Process and Control Hangzhou 310058China department of environmental Engineering Southwest University of Science and TechnologyMianyang 621010China

To better understand the interaction mechanisms of plant surfaces with polar organic compounds, sorption of 4-chlorophenol, 2,4- dichlorophenol, and 2,4,6-trichlorophenol by fruit cuticles （i.e., tomato, apple, and pepper）, and potato tuber periderm were investigated. The roles of cuticular components （waxes, cutin, cutan and sugar） on sorption of chlorophenols are quantitatively compared. Cutin and waxes govern the sorption capacity of bulk apple cuticle by hydrophobic interactions. Potato periderm with highest sugar content exhibits the lowest sorption capability for the chlorophenols. With the increase of hydrophobicity （i.e., Kow ） of sorbate, the relative contribution of lipophilic components （wax, cutin and cutan） on total sorption increases, however, the ratios of Koc to Kow decreases due to increasing ionization degree of sorbates.

关键词： potato periderm fruit cuticle chlorophenol sorption waxes cutin

Variation of Soil Microbial Biomass and Enzyme Activities at Different Growth Stages of Rice (Oryza sativa)

在线全文

学校读者我要写书评

暂无评论

Rice science 2005年第4期12卷 283-288页

作者： ZENG Lu-sheng LIAO Min chen cheng-li huang Chang-yong department of Resources science College of Environmental and Resource Sciences Zhejiang University Hangzhou 310029 China

A pot experiment was conducted under submerged conditions with hybrid rice Zhenong 7 to study the variation in the soil microbial biomass carbon （Cmic）, soil microbial biomass nitrogen （Nmic）, soil respiration rate, soil microbial metabolic quotient, soil enzyme activities, chlorophyll content, proline content and peroxidase activity （POD） in rice leaf at different growth stages. The soil Cmic, Nmic and soil respiration rate significantly increased at the early stage and then declined during rice growth, but ascended slightly at maturity. However, soil metabolic quotient declined at all the stages. Soil urease activity increased at first and then decreased, while acid phosphatase and dehydrogenase activities descended before ascended and then descended again. Soil urease activity and acid phosphatase activity showed a peak value at the tillering stage about 30 days after rice transplanting, but the peak value of dehydrogenase activity emerged at about 50 days after rice transplanting and the three soil enzymatic activities were significantly different at the different developmental stages. As rice growing, chlorophyll content in rice leaf descended at the early stage then ascended and a peak value appeared at about the 70th after rice transplanting, after that declined drastically, while POD activity increased gradually, but proline content declined gradually. There was a slight relation between rice physiological indices and soil biochemical indices, which indicated that soil biochemical characteristics were affected significantly by rice growth in the interaction system of the rice. soil and microorganisms.

关键词： rice soil microbial biomass soil metabolic quotient soil enzyme activity chlorophyll proline peroxidase

甲基赤藓糖醇磷酸胞苷酰转移酶及其抑制剂研究进展

在线全文

学校读者我要写书评

暂无评论

农药学学报 2024年第4期26卷 674-691页

作者：王吉利陈灿周雅情吴文海孙勇王星陈杰汉江师范学院化学与环境工程学院湖北十堰442000 浙江农林大学化学与材料工程学院杭州311300 浙江农林大学林业与生物技术学院杭州311300

甲基赤藓糖醇磷酸(methylerythritol phosphate,MEP)途径是生产萜类化合物前体异戊二烯基二磷酸(isopentenyl diphosphate,IPP)和二甲基烯丙基二磷酸(dimethylallyl diphosphate,DMAPP)必要的生化途径之一,该途径广泛存在于植物、细菌及病原体体内,而哺乳动物中不存在。MEP途径包含的7个关键酶都可以作为新型农药和医药的作用靶标。甲基赤藓糖醇磷酸胞苷酰转移酶(2-C-methyl-D-erythritol-4-phosphate cytidyltransferase,IspD)是MEP途径的第三个关键酶,它的活性位点亲脂性低,但拥有独特的变构位点,近年来引起研究人员的广泛关注。利用IspD小分子抑制剂来阻断MEP通路,从而间接地抑制萜类化合物的生成,可以造成病菌和植物的死亡,达到杀菌或除草目的。本文对IspD结构、催化机理、IspD抑制剂及其作用机制等内容进行了综述,可为以IspD作为靶标的抑制剂的筛选以及新型农药和医药的开发提供指导。

关键词：甲基赤藓糖醇磷酸途径甲基赤藓糖醇磷酸胞苷酰转移酶变构位点小分子抑制剂

Capturing carbon dioxide from air by using amine-functionalized metal-organic frameworks

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2024年第5期43卷 3-4页

作者： Jian Yang Guang Yang Zhijie chen Stoddart Institute of Molecular science Department of ChemistryState Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang UniversityHangzhou310058PR China zhejiang-Israel Joint Laboratory of Self-Assembling Functional Materials ZJU-Hangzhou Global Scientific and Technological Innovation CenterZhejiang UniversityHangzhou311215PR China

Along with the rapid rise of industry and technology,carbon dioxide(CO_(2))is released as a major by-product of fossil fuels *** continuous CO_(2)emission results in a steep increase of atmospheric CO_(2)concentrations and precipitated severe environmental and climatic ***,it is of great importance to reduce CO_(2)emission and atmospheric CO_(2)*** CO_(2)directly from air is one of the most straightforward strategies to mitigate atmospheric CO_(2)concentrations[1].

关键词： dioxide straight carbon

Cultivar and environmental Variation ofβ-glucan Content in Chinese Barleys

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural sciences in china 2002年第3期1卷 291-297页

作者： chen Jin-xin, Zhang Guo-ping, QIANG Xiao-lin, WANG Jun-mei and DING Shou-ren( Agronomy department, zhejiang university, hangzhou 310029 Academy of Tibet Agriculture , Lasa 850000) Agronomy department Zhejiang University Hangzhou 310029 Academy of Tibet Agriculture Lasa 850000

β-glucan is a polysaccharide compound closely related to the quality of barley used as malting, feed and food. Low β-glucan content is expected for brewing and feed barley, while high β-glucan content is desirable for food barley. The β-glucan content of barley genotypes collected from various areas of china as well as from Canada and Australia were assayed. Meanwhile a multi-locations trial was conducted to determine β-glucan content of 10 barley cultivars in 8 locations for two successive planting years. The results showed that barley genotypes from Tibet and Xinjiang had higher p-glucan content and the genotypes with higher than 8% of P-glucan content were detected in Tibet barleys, being valuable for use in the development of healthy food. Barley cultivars being planted now in winter-sowing areas of china had basically the same β-glucan content as those from Canada and Australia. Barley seeds produced in hangzhou had lower β-glucan content than seeds from the original areas. There was a highly significant difference in β-glucan content among 10 barleys, 8 locations and between years. On an average of two years, Xiumei 3 and Kongpei 1 had the highest and lowest β-glucan content, respectively, and Taian and hangzhou produced the highest and lowest P-glucan content barley seeds, respectively. Analysis of AMMI model showed that interaction effect between cultivar and environment was highly significant in both experimental years, and was dependent on cultivar, suggesting that it is important to plant the suitable cultivars in a particular area in order to obtain barley seeds with reasonable β-glucan content.

关键词： Barley p-glucan Environment Genotypes Quality

Analytical evaluation of steady-state solute distribution in through- diffusion and membrane behavior test under non-perfectly flushing boundary conditions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 258-267页

作者： Guannian chen Yuchao Li Kristin MSample-Lord Shan Tong School of Civil&environmental Engineering and Geography science Ningbo UniversityNingbo315211China MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering College of Civil Engineering and ArchitectureZhejiang UniversityHangzhou310058China Ningbo ZCONE High-tech Company Limited Ningbo315000China department of Civil and environmental Engineering Villanova UniversityVillanovaPAUSA

The through-diffusion and membrane behavior testing procedure using a closed-system apparatus has been widely used for concurrent measurement of diffusion and membrane efficiency coefficients of low-permeability clay-based barrier ***,the common assumption of perfectly flushing conditions at the specimen boundaries could induce errors in analyses of the diffusion coefficients and membrane *** this study,an innovative pseudo three-dimensional(3D)analytical method was proposed to evaluate solute distribution along the boundary surfaces of the soil-porous disks system,considering the non-perfectly flushing *** results were consistent with numerical models under two scenarios considering different inflow/outflow *** proposed model has been demonstrated to be an accurate and reliable method to estimate solute distributions along the *** calculated membrane efficiency coefficient and diffusion coefficient based on the proposed analytical method are more accurate,resulting in up to 50%less relative error than the traditional approach that adopts the arithmetic mean value of the influent and effluent *** retar-dation factor of the clay specimen also can be calculated with a revised cumulative mass ***,the simulated transient solute transport matched with experimental data from a multi-stage through-diffusion and membrane behavior test,validating the accuracy of the proposed method.

关键词： Diffusion testing Membrane behavior Coupled transport Clay barrier Transport modeling

Disparities in the Levels of Whole-Blood Epstein-Barr Virus between the Cancer and Non-Cancer Populations in zhejiang,china

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Biomedical and environmental sciences 2024年第9期37卷 993-1002页

作者： Qingjun Jia Meichun Zeng Qi chen hangzhou Center for Disease Control and Prevention(hangzhou Health Supervision Institution) Hangzhou 310021ZhejiangChina department of Pathology The First Affiliated HospitalCollege of MedicineZhejiang UniversityHangzhou 310003ZhejiangChina

Objective This study aimed to investigate the prevalence of Epstein-Barr virus(EBV)infection in patients with and without *** A total of 26,648 participants who underwent whole-blood EBV DNA(WBEBV)assays between January 1,2020,and August 31,2023,were *** chi-square test was used for categorical data analysis,and R software was used to analyze the differences in EBV DNA load levels and the diagnostic capabilities of *** Positive rates were 10.2%and 25.4%for healthy controls(HC)and patients,*** positivity rate for EBV-associated neoplasms(EN)was the highest at 7.53%,followed by leukemia(Le)at 5.49%.The subgroup analysis showed that the positivity rate for abnormal proliferation or hyperplasia(APH)was 31.9%,followed by 30.5%for *** WBEBV of patients with transplants(TP),especially living-related transplants(LT),was the highest among all *** at diagnosis was used to differentiate between infectious mononucleosis(IM)and chronic active Epstein-Barr virus(CAEBV),with a sensitivity of 67.4%(95%confidence interval[CI]:57.6-75.8)and specificity of 72%(95%CI:63.3-79.3).We conclude that the prevalence of EBV infection is low in the healthy population in this region and that a high EBV load at baseline is more common in LT,IM,and Lymphocyte Leukemia(LL).Conclusion This study used a large-sample survey to characterize the prevalence of whole-blood EBV levels in various diseases,including the stages and *** EBV detection rate was higher in patients with malignant disease than in those with benign *** study provides clinicians with baseline information regarding EBV-associated diseases.

关键词： Epstein-Barr virus Epstein-Barr virus DNA Whole blood Epstein-Barr virus DNA Viral load