检索结果-南通市图书馆

Studies of Solvent Effects on Structure and Low Frequency Vibrational Spectra of 2,4-Dinitrotoluene

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2009年第3期25卷 373-376页

作者： WANG Lin JIN Ming-xing liu Hang DING Da-jun Institute of Atomic and Molecular Physics Jilin University Changchun 130012 P. R. China

Solvent effects on 2,4-dinitrotoluene（2,4-DNT） molecule in different solvents（toluene, ethanol, and water） were studied via DFT PCM method at B3LYP/6-311＋G（d,p） level. The influences of these solvents on the molecular structure, vibrational spectra, charge distribution, and dipole moment were studied as well. The results show that PCM computations are successful in describing the vibrational spectra of 2,4-DNT molecules in these solutions and the solvent effects on the low frequency vibrational spectra are weak.

关键词： Density functional theory Solvent effect Polarizable continuum model 2,4-Dinitrotoluene

Application of numerical simulation to flow induced corrosion in flowing seawater system

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2004年第z1期14卷 439-442页

作者： liu Jing-jun LIN Yu-zhen YONG xing-yue LI Xiao-yu School of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China School of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China School of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China School of Materials Science and Engineering Beijing University of Chemical Technology Beijing 100029 China

An established model was presented as a new kind of means for investigating flow induced corrosion. In this method the near-wall hydrodynamic parameters including wall shear stress τ and mass transfer coefficient k near the wall of materials can be numerically calculated, and combining corrosive kinetics tested by experiments, the corrosion rates can be also calculated accurately. The flow induced corrosion mechanism was further verified by numerical results in this model, and the various corrosion phenomena were explained. The modelled results also show that the ability to accurately utilize numerical method to study flow induced corrosion strongly to some extent depends on material corrosive kinetics processes tested by experiments.

关键词： flow induced corrosion numerical simulation near-wall hydrodynamic parameters mechanism

Light-and Heat-Controlled Formation of Osmanaphthalenes and Osmanaphthalynes

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

Chinese Journal of Chemistry 2022年第24期40卷 2853-2860页

作者： Ming-xing Zhang Xiaofei Yang Zhiqiang Xu jun Yin Sheng Hua liu Key Laboratory of Pesticide and Chemical Biology Ministry of EducationCollege of ChemistryCentral China Normal UniversityWuhanHubei430079 China Hubei Key Laboratory of Purification and Application of Plant Anti-cancer Active Ingredients College of Chemistry and Life ScienceHubei University of EducationWuhanHubei430205 China Key Laboratory for Green Chemical Process of Ministry of Education School of Chemical Engineering and PharmacyWuhan Institute of TechnologyWuhanHubei430205 China

mple and efficient synthesis of metalla-aromatics with tailored distinctive optical,magnetic,redox,and light-emitting properties is attractive yet *** have now successfully synthesized three paramagnetic osmanaphthalenes bearing different electron-donating groups as well as the first osmabenzo[b]carbazole containing an osmanaphthalene unit with four fused rings in good yields by subjecting suitable osmium carbyne precursors to a visible-light-induced *** contrast,the four corresponding diamagnetic cyclic metal carbynes containing an osmanaphthalyne unit were obtained from the same osmium carbyne precursors by a heating *** lowest-energy absorptions of the paramagnetic osmanaphthalenes are red-shifted compared to the corresponding ***,experimental observations including X-ray analysis as well as nucleus-independent chemical shift(NICS),anisotropy of the current-induced density(AICD)calculations revealed these novel osmapolycycles bearing phosphonium substituents to be of aromatic character.

关键词： Metallacycles Aromaticity Osmanaphthalyne Osmanaphthalene Photolysis

Multi-objective optimization design of deviation-correction trajectory considering the production loss in shale gas cluster well

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

Petroleum Science 2022年第6期19卷 2995-3003页

作者： Zi-jun Dou Yong-Sheng liu xing Qin De-Li Gao Gan-Sheng Yang Key Laboratory of Deep Geological Drilling Technology of Ministry of Natural Resources China University of GeosciencesBeijing 100083China Sinopec Research Institute of Petroleum Engineering Beijing 100101China MOE Key Lab of Petroleum Engineering China University of PetroleumBeijing 102249China

In shale gas mining,the inter-fracture interference effect will significantly occur if the actual well deviates from the planned *** reduce production loss,operators want to get back on the planned trajectory economically and *** on this,a multi-objective optimization model of deviationcorrection trajectory is established considering the production loss ***,the functional relationship between the production envelope and the fracturing depth is constructed,and the production loss is obtained by combining the calculation method of volume *** on the proposed“double-arc”trajectory design method,the production loss of the fracture on the deviation-correction trajectory is ***,combined with the well profile energy evaluation,a new optimization model of deviation-correction trajectory is *** results demonstrate that after optimizing the fracturing depth,the production loss of the deviation-correction trajectory is reduced by 13.2%.The maximum curvature value results in a trajectory with a minimum production loss yet a maximum well profile *** proposed model reduces the well profile energy by 15.6%compared with the existing *** is proved that the proposed model can reduce the probability of drilling accidents and achieve high gas production in the later mining *** study fully considers various factors affecting horizontal wells in the fracturing area,which can provide theoretical guidance for the design of deviationcorrection trajectory.

关键词： Shale gas Inter-fracture interference effect Production loss Deviation-correction trajectory Multi-objective optimization

Molecular bases of morphologically diffused tumors across multiple cancer types

在线全文

学校读者我要写书评

暂无评论

National Science Review 2022年第11期9卷 65-67页

作者： Dingyun liu Feiyang xing Yueying Wang jun Xiao Zheng An Ying Xu College of Computer Science and Technology Jilin University Center for Cancer Systems Biology China-Japan Union Hospital of Jilin University School of Life Sciences Jilin University China Computational Systems Biology Lab Department of Biochemistry and Molecular Biology and Institute of BioinformaticsUniversity of Georgia

Diffuse gastric cancer (DGC) and intestinal gastric cancer (IGC) are the two main gastric cancer subtypes [1]. Morphologically, DGC consists of numerous disjoint tiny tumors while IGC forms one or a few solid tumors (Supplementary Supplementary Fig. S1)[1,2]. In-depth studies have discovered that DGCs generally have an ill-defined or missing glandular structure and reduced cell–cell adhesion,

关键词： identification enantioselective semisynthesis (−)-anisomelic acid oral agent anti-SARS-CoV-2

基于自适应续流比的混合式步进电机转矩脉动抑制方法

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

陕西科技大学学报 2025年第1期43卷 142-151,202页

作者：王焜刘宝泉刘艺张浩铭刘俊陕西科技大学电气与控制工程学院陕西西安710021 西安西电高压开关有限责任公司陕西西安710018

混合式步进电机细分驱动存在较大的电流纹波,导致转矩脉动明显.通过分析H桥驱动电路的续流过程,提出一种基于自适应续流比的混合式步进电机转矩脉动抑制方法.该方法利用环型分配器产生的细分指令电流i ref与实际电流i相比较,以区分当前... 详细信息

混合式步进电机细分驱动存在较大的电流纹波,导致转矩脉动明显.通过分析H桥驱动电路的续流过程,提出一种基于自适应续流比的混合式步进电机转矩脉动抑制方法.该方法利用环型分配器产生的细分指令电流i ref与实际电流i相比较,以区分当前时刻所需的续流模式.在快速续流模式下,实时监测电流指令与实际电流的差值Δi ref,通过自适应系数k动态调节续流时间,直至电机相电流快速下降至给定电流i ref后切换至缓慢续流模式.对续流时长与快速续流占总续流时间的比例自适应调节以适应不同工况下步进电机的平稳运行,有效降低了转矩脉动.最后,搭建MATLAB/Simulink仿真平台并进行实验验证,结果表明,与传统混合续流控制相比,所提方法能够有效减小步进电机的转矩脉动.

关键词：混合式步进电机自适应续流比电流纹波转矩脉动

维普期刊数据库博看期刊

An SPH wave-current flume using open boundary conditions

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2020年第3期32卷 536-547页

作者： xing-ye Ni Wei-bing Feng Shi-chang Huang Zi-jun Hu Yong liu Zhejiang Institute of Hydraulics and Estuary Hangzhou 310020China College of Harbor Coastal and Offshore EngineeringHohai UniversityNanjing 210098China

In this paper, a novel numerical wave-current flume is implemented based on the Smoothed Particle Hydrodynamics (SPH) method. The proposed flume is more stable and computationally efficient than conventional ones because it cancels wave paddles or sponge layers while using a non-reflective open boundary condition to simultaneously generate and absorb waves and currents. Numerical tests of nonlinear regular waves interacting with steady currents in the same/opposite directions indicate that the wave-current interactions mainly affect the horizontal velocity distributions in the water body, with little influence on the vertical movements. Water particle trajectories are stretched, and the mass transportation effects are enhanced when the waves and currents are in the same direction. When the directions are opposed, the trajectories, as well as the mass transportation, are compressed, suppressed and even reversed. The applications of solitary wave-current interaction over a submerged bump further show that the relative direction between the wave and the current has remarkable influence on the wave breaking pattern over an underwater obstacle.

关键词： Smoothed particle hydrodynamics(SPH) wave-current interaction wave-current flume open boundary condition particle trajectory

Molecular mechanisms of intermuscular bone development in fish:a review

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

Zoological Research 2021年第3期42卷 362-376页

作者： Bo Li Yuan-Wei Zhang Xiao liu Li Ma jun-xing Yang Cave Fish Development and Evolution Research Group Kunming Institute of ZoologyChinese Academy of SciencesKunmingYunnan 650223China College of Life Sciences Capital Normal UniversityBeijing 100048China State Key Laboratory of Genetic Resources and Evolution Kunming Institute of ZoologyInnovative Academy of Seed DesignChinese Academy of SciencesKunmingYunnan 650223China Yunnan Key Laboratory of Plateau Fish Breeding Yunnan Engineering Research Center for Plateau-Lake Health and RestorationKunming Institute of ZoologyChinese Academy of SciencesKunmingYunnan 650223China

Intermuscular bones(IBs)are slender linear bones embedded in muscle,which ossify from tendons through a process of intramembranous ossification,and only exist in basal *** are essential for fish swimming,but they present a choking risk during human consumption,especially in children,which can lead to commercial risks that have a negative impact on the aquaculture of these *** this review,we discuss the morphogenesis and functions of IBs,including their underlying molecular mechanisms,as well as the advantages and disadvantages of different methods for IB studies and techniques for breeding and generating IB-free fish *** review reveals that the many key genes involved in tendon development,osteoblast differentiation,and bone formation,e.g.,scxa,msxC,sost,twist,bmps,and osterix,also play roles in IB ***,this paper provides useful information for the breeding of new fish strains without IBs via genome editing and artificial selection.

关键词： Intermuscular bones Molecular mechanisms Intramembranous ossification Bone formation Genome editing Artificial selection

Effect of type 2 diabetes mellitus on flavonoid pharmacokinetics and tissue distribution after oral administration of Radix Scutellaria extract in rats

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Natural Medicines 2018年第6期16卷 418-427页

作者： ZHANG Xue-Ju liu Shu xing jun-Peng liu Zhi-Qiang SONG Feng-Rui National Center of Mass Spectrometry in Changchun Jilin Province Key Laboratory of Chinese Medicine Chemistry and Mass SpectrometryChangchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Chinese Academy of Sciences Beijing 100039China

Radix Scutellaria is widely applied to the treatment of diabetes mellitus in China. Its main bioactive constituents contain baicalin, wogonoside, oroxyloside, and their aglycones. To investigate the effect of type 2 diabetes mellitus on both pharmacokinetics and tissue distribution of these flavonoid compounds, the six flavonoids in plasma and tissues from the normal and type 2 diabetic rats after oral administration of Radix Scutellaria extract were simultaneously measured by ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) method. The results showed that baicalin, wogonoside, and oroxyloside had higher Cmax and AUC values(P < 0.05) in type 2 diabetic rats than that in normal rats and the tissue-distribution behaviors of the six flavonoid compounds in hearts, livers, spleens, lungs, kidneys, brains, pancreas, fat and muscle of the type 2 diabetic rats showed obviously differences from the normal rats(P < 0.05). In conclusion, the differences in the pharmacokinetics of oroxyloside and tissue distribution of the six flavanoids in Radix Scutellaria extract between diabetic and normal rats were found for the first time. The results from the present study provided a crucial basis for a better understanding of in vivo anti-diabetic mechanism of action of the six flavonoids from Radix Scutellaria.

关键词： Radix Scutellaria Diabetes mellitus Flavonoid Pharmacokinetics Tissue distribution