检索结果-南通市图书馆

Chinese Journal of Chemical Physics 2008年第6期21卷 526-534页

作者： Ling Qiu xue-dong gong He-ming Xiao Institute for Computation in Molecular and Material Science School of Chemical Engineering Nanfing University of Science and Technology Nanjing 210094 China Key Laboratory of Nuclear Medicine Ministry of Health Jiangsu Institute of Nuclear Medicine Wuxi 214063 China

Density functional theory method was employed to study the effect of the nitroamino group as a substituent in cyclopentane and cyclohexane, which usually construct polycyclic or caged nitramines. Based on the optimized molecular structures of two groups of monocyclic nitramines at the B3LYP/6-31G^＊＊ level, the infrared （IR） spectra were obtained and assigned by harmonic vibrational analysis. The calculated results agree reasonably with the available experimental data. According to the principles of statistic thermodynamics, thermodynamic properties were derived from the IR spectra, which were linearly correlated with the number of nitroamino groups as well as the temperature. The contributions of nitroamino groups to thermodynamic properties are in accord with the group additivity.

关键词： Density functional theory Substituent effect Monocyclic nitramine Infrared spectrum Thermodynamic property

Molecular Dynamics Study of Interaction between Acrylamide Copolymers and Alumina Crystal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2012年第5期25卷 571-576,I0003,I0004页

作者： Feng-he Wang Feng-yun Wang xue-dong gong Department of Environmental Science and Engineering Nanjing Normal UniversityNanjing 210042China Department of Chemistry Nanjing University of Science and TechnologyNanjing 210094China

Four acrylamide polymer flocculants, anionic polyacrylamide P（AA-co-AM）, cationic poly- acrylamide P（DMB-co-AM）, nonionic polyacrylamide P（AM）, and hydrophobical polyacry- lamide P（OA-co-AM） have been prepared by copolymerizing with acrylic acid, cationic monomer dimethylethyl （acryloxyethyl） ammonium bromide （DMB） and hydrophobical monomer octadecyl acrylate with acrylamide. The interactions between the flocculants with the （012） surface of alumina crystal （A1203） have been simulated by molecular dynamics method. All the polymers can bind tightly with A1203 crystal, the interaction between the O of polymers and A1 of the （012） surface of A1203 is significantly strong. The order of binding energy is as follows： P（DMB-co-AM）〉P（OA-co-AM）〉P（AA-co-AM）〉P（AM）, implying a better flocculation performance of P（DMB-co-AM） than the others. Analy- sis indicates that binding energy is mainly determined by Coulomb interaction. Bonds are found between the O atoms of the polymers and the A1 atoms of A1203. The poly- mers＇ structures deform when they combine with A1203 crystal, but the deformation en- ergies are low and far less than non-bonding energies. Flocculation experiments in sus- pension medium of l%Kaolin show a transmittancy of 90.8% for 6 mg/L P（DMB-co-AM） and 73.0% for P（AM）. The sequence of flocculation performance of four polymers is P（DMB-co-AM）〉P（OA-co-AM）〉P（AA-co-AM）〉P（AM）, which is in excellent agreement with the simulation results of binding energy.

关键词： Molecular dynamics simulation Acrylamide copolymer Binding energy Floc-culation

Molecular Dynamics Simulation on Scale Inhibition Mechanism of Polyepoxysuccinic Acid to Calcium Sulphate

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2012年第2期25卷 219-225,I0004页

作者： Jian-ping Zeng Feng-he Wang Chen Zhou xue-dong gong Department of Chemistry Nanjing University of Science and TechnoloEyNanjing 210094China School of Chemical and Biological Engineering Yancheng institute of TechnologyYancheng 224003China Department of Environmental Science and Engineering Nanjing Normal UniversityNanjing 210042China Zhefiang Electric Power Test and Research Institute Hangzhou 310014China

Molecular dynamics simulation has been performed to simulate the interaction between PESA and the （001） face of anhydrite crystal CaSO4 at different temperatures with the presence of various number of H2O molecules. The results show that PESA can effectively prevent the growth of CaSO4 scale at 323-343 K. At the same temperature, the binding energy between PESA and the （001） face of CaSO4 for systems with various number of H2O has the order of E-bind（OH2O）〉Ebind（200-400H2O）〉E, bind（lOOH2O）. For the same system at different temperatures the binding energies are close and are mainly contributed from the Coulomb interaction, including ionic bonds. The bonds are formed between the calcium atoms of anhydrite scale crystal and the Hydrogen bonds are formed between the O oxygen atoms of the carboxyl group of PESA. atoms of the carboxyl group of PESA and the H atoms of H2O. van der Waals interaction is conducive to the stability of the system of PESA, H2O, and CaSO4. The radial distribution functions of O（carbonyl of PESA）-H（H2O）, O（CaSO4）-H（H2O）, and O（CaSO4）-H（PESA） imply that solvents have effects on the anti-scale performance of PESA to CaSO4.

关键词： Polyepoxysuccinic acid Calcium sulphate Molecular dynamics Binding en-ergy Radial distribution function

Molecule aging induced by electron attacking

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 Energy Chemistry 2024年第6期93卷 519-525,I0013页

作者： Ping Song Yining dong xue gong Mingbo Ruan Baoxin Ni Xuanhao Mei Kun Jiang Weilin Xu State Key Laboratory of Electroanalytical Chemistry and Jilin Province Key Laboratory of Low Carbon Chemical Power Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022JilinChina School of Applied Chemistry and Engineering University of Science and Technology of Chin1Hefei 230026AnhuiChina Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Collaborative Innovation Center of Chemistry for Energy MaterialsDepartment of ChemistryFudan UniversityShanghai 200438China

Here we propose a new concept of"molecule aging":with some special treatment,a molecule could be"aged"by losing some unknown tiny particles or pieces from atoms in the molecule,Such"aging"or loss of unknown tiny particles does not change apparently its molecular structure or chemical composition,but some physicochemical properties could be changed *** further confirm such"molecule aging"via a long-term electron attacking to age water(H_(2)O)*** IR spectra show no structural difference between the fresh water and the aged one,while the NMR spectra show that the electron attacking can decrease the size of water *** facts indicate that the electron attacking indeed can"affect"the structure of water molecule slightly but without damaging to its basic molecule *** exploration reveals that the hydrogen evolution reaction(HER)activity of the aged water molecule is lower than the fresh water on the same Pt/C *** density functional theory calculations indicate that the shortened O-H bond in H_(2)O indeed can present lower HER activity,so the observed size decrease of water clusters from NMR probably could be attributed to the shortening of O-H bond in water *** results indicate significantly that the molecule aging can produce materials with new functions for new possible applications.

关键词： Aging of molecules Electron attacking Full width at half maxima Hydrogen evolution reaction

Projections of summer light rain frequency in typical terrain over eastern China under wind speed constraint

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第6期67卷 1885-1894页

作者： xuechen dong Daoyi gong Cuicui SHI Institute of Disaster Risk Science Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Key Laboratory of Environmental Change and Natural Disaster MOEFaculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China School of National Safety and Emergency Management Beijing Normal UniversityBeijing 100875China School of Systems Science Beijing Normal UniversityBeijing 100875China

The variation in near-surface wind speed is a key dynamic parameter in the orographic effect of precipitation over eastern *** this study,we used the latest high-resolution outputs from six GCMs in CMIP6-HighResMIP to evaluate the performance of high-resolution models in simulating the orographic precipitation characteristics of typical mountainous areas in summer over eastern *** orographic precipitation under warming scenarios was projected and constrained according to observational *** results indicated that during the contemporary climate reference period(1979-2009),although the relationship between model-simulated near-surface wind speed and orographic light rain frequency was consistently stable,the sensitivity of the orographic light rain frequency to surface wind variability was generally underestimated,with a deviation approximately 24.1% lower than the observational *** estimated orographic light rain frequency corrected based on the observed near-surface wind speed under a 1.5℃ warming scenario,was 36.1% lower than that of the contemporary period;this reduction was 8.6 times that without the wind speed constraint(4.2%).The MRI-AGCM3-2-S model,with a longer dataset,demonstrated relatively stable reductions in orographic light rain frequency under different warming scenarios(1.5℃,2℃,3℃,and 4℃)after the application of wind speed *** all cases,the reductions exceeded those for the predictions made without the wind speed constraint.

关键词： Frequency of orographic light rain HighResMIP High-resolution projection Observational constraint Eastern China

Oxidation behavior of low-grade vanadiferous titanomagnetite concentrate with high titanium

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第2期31卷 329-341页

作者： Jin-sheng Liu Zhen-xing Xing gong-jin Cheng xue-yong Ding Xiang-xin xue School of Metallurgy Northeastern UniversityShenyang110819LiaoningChina Liaoning Key Laboratory of Recycling Science for Metallurgical Resources Shenyang110819LiaoningChina Innovation Research Institute of Vanadium and Titanium Resource Industry Technology Northeastern UniversityShenyang110819LiaoningChina

In order to clarify the oxidation mechanisms and make better use of the low-grade vanadiferous titanomagnetite concentrate with high titanium(LVTC),the oxidation behavior of LVTC was *** results showed that oxidation degree was achieved within 90 min when temperature was not lower than 700°C,and the main phases of the oxidized LVTC consisted of Fe9TiO15,Fe2O3,CaSiTiO5 and a small amount of *** temperature is favorable to the formation of *** surface of LVTC gradually becomes rough,with fine particles of needle-like and granular shape appearing on the surface,which finally turn from laminar to creamy,spread out,and are interspersed with many tiny *** phase oxidation paths in LVTC were as follows:(1)Fe2.75Ti0.25O4→Fe9TiO15+Fe2O3;(2)Fe2.75Ti0.25O4→Fe2O3+FeTiO3→Fe2TiO5;(3)FeTiO3→Fe2O3+Fe2Ti3O9→*** is predominantly mesoporous whether oxidized or not,with the pores mainly distributed in the range of 2–40 nm,and the specific surface area of LVTC decreases significantly with increasing temperature.

关键词： Low-grade vanadiferous titanomagnetite concentrate Oxidation degree Phase transformation Micromorphology Oxidation path Pore structure

SwiftTheft: A Time-Efficient Model Extraction Attack Framework Against Cloud-Based Deep Neural Networks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2024年第1期33卷 90-100页

作者： Wenbin YANG xueluan gong Yanjiao CHEN Qian WANG Jianshuo dong School of Cyber Science and Engineering Wuhan University School of Computer Science Wuhan University College of Electrical Engineering Zhejiang University

With the rise of artificial intelligence and cloud computing, machine-learning-as-a-service platforms,such as Google, Amazon, and IBM, have emerged to provide sophisticated tasks for cloud applications. These proprietary models are vulnerable to model extraction attacks due to their commercial value. In this paper, we propose a time-efficient model extraction attack framework called Swift Theft that aims to steal the functionality of cloud-based deep neural network models. We distinguish Swift Theft from the existing works with a novel distribution estimation algorithm and reference model settings, finding the most informative query samples without querying the victim model. The selected query samples can be applied to various cloud models with a one-time selection. We evaluate our proposed method through extensive experiments on three victim models and six datasets, with up to 16 models for each dataset. Compared to the existing attacks, Swift Theft increases agreement(i.e., similarity) by 8% while consuming 98% less selecting time.

关键词： Performance evaluation Cloud computing Analytical models Computational modeling Estimation Artificial neural networks Artificial intelligence

Rural labor migration and farmers’arrangements of rice production systems in Central China:Insight from the intergenerational division of labor

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2024年第9期23卷 3200-3214页

作者： xue Shen Quanyu Yang Rongjun Ao Shengsheng gong Key Laboratory for Geographical Process Analysis&Simulation of Hubei Province/College of Urban and Environmental Sciences Central China Normal UniversityWuhan 430079China

Rice production is crucial for food security in China,and its relationship with rural labor migration has been studied *** migration in rural China has taken new forms in recent *** has been a discernible trend wherein adult children have started migrating to cities while their elderly parents return to villages to re-engage in on-farm *** phenomenon has notably shaped the intergenerational division of labor(IDL)within ***,it remains to be seen how farmers adjust their rice production systems in response to the *** age of 60 years for employment injury insurance is the eligibility threshold for off-farm employment and is used to obtain a source of exogenous variation in the *** on a representative household survey of 1,752 rice farmers in the Hubei Province of Central China,our fuzzy regression discontinuity analysis reveals that farmers in IDL households are more likely to adopt ratoon rice(RR)than single cropping rice(SR)or double cropping rice(DR).The effect of the IDL varies under different levels of operational scales and specialized agricultural service *** analysis suggests that farmers’arrangements are associated with two potential mechanisms of downward intergenerational *** transfer for urban housing purchases increases RR in IDL households,and time transfer for intergenerational childcare significantly promotes SR in IDL *** study enhances the understanding of the relationship between rural labor migration and rice production in China,providing a reference for adjusting rice production systems to ensure food security.

关键词： labor migration intergenerational division of labor rice production systems fuzzy regression discontinuity Central China

Eco-evolutionary evidence for the global diversity pattern of Cycas(Cycadaceae)

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2024年第6期66卷 1170-1191页

作者： Jian Liu Anders JLindstrom Yiqing gong Shanshan dong Yusheng(Chris)Liu Shouzhou Zhang Xun gong CAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China Department of Economic Plants and Biotechnology Yunnan Key Laboratory for Wild Plant ResourcesKunming Institute of BotanyChinese Academy of SciencesKunming 650201China University of Chinese Academy of Sciences Beijing 100049China Global Biodiversity Conservancy 144/124 Moo3Soi Bua ThongBangsalaeSattahipChonburi 20250Thailand Key Laboratory of Southern Subtropical Plant Diversity Fairy Lake Botanical GardenShenzhen&Chinese Academy of SciencesShenzhen 518004China Department of Earth and Environmental Sciences Indiana University-IndianapolisIndianapolisIN 46202USA

The evolution of the latitudinal diversity gradient(LDG),characterized by a peak in diversity toward the tropics,has captured significant attention in evolutionary biology and ***,the inverse LDG(i-LDG)mechanism,wherein species richness increases toward the poles,remains inadequately *** are among one of the oldest lineages of extant seed plants and have undergone extensive diversification in the ***,the extant cycad abundance exhibits an i-LDG pattern,and the underlying causes for this phenomenon remain largely ***,using 1,843 nuclear genes from a nearly complete sampling,we conducted comprehensive phylogenomic analyses to establish a robust species-level phylogeny for Cycas,the largest genus within *** then reconstructed the spatial-temporal dynamics and integrated global environmental data to evaluate the roles of species ages,diversification rates,contemporary environment,and conservatism to ancestral niches in shaping the i-LDG *** found Cycas experienced decreased diversification rates,coupled with the cooling temperature since its origin in the Eocene from continental *** regions have distinctively contributed to the formation of i-LDG for Cycas,with the northern hemisphere acting as evolutionary museums and the southern hemisphere serving as ***,water-related climate variables,specifically precipitation seasonality and potential evapotranspiration,were identified as paramount factors constraining Cycas species richness in the rainforest biome near the ***,the adherence to ancestral monsoonal climates emerges as a critical factor in sustaining the diversity *** study underscores the imperative of integrating both evolutionary and ecological approaches to comprehensively unravel the mechanisms underpinning global biodiversity patterns.

关键词： cycads latitudinal diversity gradient niche conservatism spatiotemporal diversification species richness

A Robust N-Terminal Pro-Brain Natriuretic Peptide Assay for Clinical Diagnosis of Heart Failure in Elderly Patients

在线全文

学校读者我要写书评

暂无评论

Journal of Analysis and Testing 2024年第1期8卷 74-82页

作者： xue gong Jiangling Wu Jiajia Zhang Zhongwei Jiang Yi Wang Pu Zhang Engineering Research Center for Biotechnology of Active Substances(Ministry of Education) Chongqing Key Laboratory of Green Synthesis and ApplicationsCollege of ChemistryChongqing Normal UniversityChongqing 401331China Chongqing Research Center for Pharmaceutical Engineering College of PharmacyChongqing Medical UniversityChongqing 400016China Department of Clinical Laboratory University Town Hospital of Chongqing Medical UniversityChongqing 401331China

Heart failure(HF)is a clinical hallmark of cardiovascular syndrome leading to substantial morbidity,repeated hospitalization,and enormous healthcare *** elderly populations continue to increase,biomarker-guided diagnosis and treatment for age-related cardiac decline have become *** evidence demonstrates that N-terminal proBNP(NT-proBNP)can provide a unique window into the diagnosis and risk stratification with ***,a simple yet robust aptasensor is developed for on-site recognizing the NT-proBNP by its targeting aptamer,thus achieving the accurate diagnosis of *** aptasensing system is prepared by absorbing the fluorophore-labeled aptamer strand onto the graphene oxide(GO),leading to efficient quenching without possible off-site signal *** aptamer strand can specifically identify target NT-proBNP molecules via a versatile conformational transformation,resulting in the desorption of the aptamer-NTproBNP complexes from GO and re-generation fluorescence signal,thus allowing sensitive detection of NT-proBNP in 37 clinical blood *** advantage of the high specificity of aptamer-guaranteed recognitions of NT-proBNP,this aptasensor system readily achieves better diagnostic performance for HF than commercially adopted chemiluminescence immunoassay(Siemens,CLIA)in hospitals in terms of accuracy(89.2%vs 83.8%),specificity(89.5%vs 84.2%),and positive predictive value(88.9%vs 83.3%).This work provides a stable option for the diagnosis and treatment of elderly HF-related diseases inclinics.

关键词： NT-proBNP Graphene oxide Aptamer Heart failure Clinical diagnosis