检索结果-南通市图书馆

Investigation on the potential barrier to internal rotation in molecules——Ab initio calculation and energy partition of the internal rotation barrier in complex molecule H_3N-BH_3

在线全文

学校读者我要写书评

暂无评论

chinese Journal of chemistry 1992年第5期10卷 385-389页

作者： ZHANG, Qi-Yuan yan, ji-min institute of chemistry, {2. Academy of sciences, beijing 100080 institute of chemistry Chinese Academy of Sciences Beijing 100080

Based on the ab initio/6-31Gcalculation, the potential barrier to internal rotation in mol-ecule HN--BHhas been studed by means of PD/LSF atomic charge model and Buckingham（exp--6-1）energy partition method. The results indicate that the order of the contributions of the componentsto the total energy barrier △E is |△V|（electrostatic） >|△V| （charge transfer）>|△V| （exchangerepulsion）>|△V| （dispersion）. For △Vthere are maxima at θ= 30°and 90°, and a saddle atθ= 60°. There are good linear relationships for the total barrier △E, △Vand △Vwith cos3θrespectively, and the same for the dipole moment from PD/LSF model (μ) and that from abinitio calculation (μ) vs. cos3θ respectively.

关键词： Ab initio calculation and energy partition of the internal rotation barrier in complex molecule H3N-BH3

Basic Survey Scheduling for the Wide Field Survey Telescope(WFST)

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第1期24卷 59-69页

作者： yan-Peng Chen ji-An jiang Wen-Tao Luo Xian-Zhong Zheng min Fang Chao yang Yuan-Yu Hong Zong-Fei Lü Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China Department of Astronomy University of Science and Technology of ChinaHefei 230026China National Astronomical Observatory of Japan National Institutes of Natural Sciences2-21-1 OsawaMitakaTokyo 181-8588Japan institute of Deep Space sciences Deep Space Exploration LaboratoryHefei 230026China

Aiming at improving the survey efficiency of the Wide Field Survey Telescope, we have developed a basic scheduling strategy that takes into account the telescope characteristics, observing conditions, and weather conditions at the Lenghu site. The sky area is divided into rectangular regions, referred to as “tiles,” with a size of2.. 577 × 2.. 634 slightly smaller than the focal area of the mosaic CCDs. These tiles are continuously filled in annulars parallel to the equator. The brightness of the sky background, which varies with the moon phase and distance from the moon, plays a significant role in determining the accessible survey fields. Approximately 50connected tiles are grouped into one block for observation. To optimize the survey schedule, we perform simulations by taking into account the length of exposures, data readout, telescope slewing, and all relevant observing conditions. We utilize the Greedy Algorithm for scheduling optimization. Additionally, we propose a dedicated dithering pattern to cover the gaps between CCDs and the four corners of the mosaic CCD array, which are located outside of the 3° field of view. This dithering pattern helps to achieve relatively uniform exposure maps for the final survey outputs.

关键词： telescopes surveys Moon

Cyclic Beam Direction of Arrival Estimation Method for Ship Propeller Noise

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2024年第4期23卷 883-896页

作者： ZHANG Xiaowei NIE Weihang XU ji yan Yonghong The Key Laboratory of Speech Acoustics and Content Understanding Institute of AcousticsChinese Academy of SciencesBeijing 100190China The Key Laboratory of Speech Acoustics and Content Understanding Institute of AcousticsUniversity of Chinese Academy of SciencesBeijing 100049China The State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China

In underwater acoustic applications,the conventional cyclic direction of arrival algorithm faces challenges,including a low signal-to-noise ratio and high bandwidth when compared with modulated *** response to these issues,this paper introduces a novel,robust,and broadband cyclic beamforming *** proposed method substitutes the conventional cyclic covariance matrix with the variance of the cyclic covariance matrix as its primary *** that the same frequency band shares a common steering vector,the new algorithm achieves superior detection performance for targets with specific modulation frequencies while suppressing interference signals and background *** results demonstrate a significant enhancement in the directibity index by 81%and 181%when compared with the traditional Capon beamforming algorithm and the traditional extended wideband spectral cyclic MUSIC(EWSCM)algorithm,***,the proposed algorithm substantially reduces computational complexity to 1/40th of that of the EWSCM algorithm,employing frequency band statistical averaging and covariance matrix variance.

关键词： cyclostationarity direction of arrival extended wideband spectral cyclic music cyclic covariance matrix

Robust Correlation Clustering Problem with Locally Bounded Disagreements

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第1期29卷 66-75页

作者： Sai ji min Li Mei Liang Zhenning Zhang institute of Mathematics Hebei University of TechnologyTianjin 300401China School of Mathematics and Statistics Shandong Normal UniversityJinan 250358China College of Statistics and Data Science Beijing University of TechnologyBeijing 100124China Department of Operations Research and Information Engineering Beijing University of TechnologyBeijing 100124China

min-max disagreements are an important generalization of the correlation clustering problem(CorCP).It can be defined as *** a marked complete graph G=(V,E),each edge in the graph is marked by a positive label"+"or a negative label"_"based on the similarity of the connected *** goal is to find a clustering C of vertices V,so as to minimize the number of disagreements at the vertex with the most ***,the disagreements are the positive cut edges and the negative non-cut edges produced by clustering *** paper considers two robust min-max disagreements:min-max disagreements with outliers and min-max disagreements with *** parameter δ∈(0,1/14),we first provide a threshold-based iterative clustering algorithm based on LP-rounding technique,which is a(1/δ,7/(1-14δ))-bi-criteria approximation algorithm for both the min-max disagreements with outliers and the min-max disagreements with outliers on one-sided complete bipartite ***,we verify that the above algorithm can achieve an approximation ratio of 2. for min-max disagreements with penalties when we set parameter δ=1/2..

关键词： min-max disagreements outliers penalties approximation algorithm LP-rounding

Hydrothermal hydrogenation/deoxygenation of palmitic acid to alkanes over Ni/activated carbon catalyst

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 Chemical Engineering 2024年第2期66卷 8-18页

作者： min Lin Yuhao yan Xiaoxian Li Rui Li Yulong Wu MOE Engineering Center of Forestry Biomass Materials and Bioenergy Beijing Forestry UniversityBeijing 100083China institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China Key Laboratory of Advanced Reactor Engineering and Safety of ministry of Education Tsinghua UniversityBeijing 100084China

To produce paraffin from hydrogenation/deoxygenation of palmitic acid,model compound of bio-oil obtained by hydrothermal liquefaction(HTL)of microalgae has been an attractive focus in recent *** order to avoid energy-intensive separation process of water and bio-oil,it is of importance that deoxygenation upgrading of fatty acids under hydrothermal conditions similar to HTL ***,it is the first time to explore the application of activated carbon(AC)-supported non-noble-metal catalysts,such as Ni,Co,and Mo,and so on,in the hydrothermal hydrogenation/deoxygenation of long-chain fatty acids,and the obtained Ni/AC-H(the Ni/AC was further H_(2.pre-reduced)is one of the best *** addition,it is found that the catalytic activity can be further improved by H_(2.pre-reduction of *** results that are more low valences of nickel and oxygen vacancy can be obtained after H_(2.pre-reduction,thus significant promoting the deoxygenation especially the decarbonylation pathway of fatty *** total alkanes yield can reaches 95.9%at optimal conditions(2.0℃,360 min).This work confirmed that the low-priced AC-supported non-noble-metal catalysts have great potential compared with the noble-metal catalyst,in hydrothermal upgrading of bio-oil.

关键词： Bio-oil Fatty acids Deoxygenation Hydrothermal upgrading

Organic Integration of Traditional chinese and Western Medicines—Future of Clinical Practice Guidelines of Integrated Traditional chinese and Western Medicines

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Integrative Medicine 2024年第4期30卷 359-365页

作者： XIE Ying-lan HAN Fei jiN Ying-hui DING yan-bing GUO jing ji Dong-xiao ZHANG Teng CHENXiao-min SHANG Hong-cai Department of Traditional chinese Medicine Encephalopathy Hubei Provincial Hospital of Traditional Chinese MedicineWuhan(430074)China Department of Traditional chinese Medicine Encephalopathy Hubei Province Traditional Chinese Medicine Research InstituteWuhan(430074)China Xuanwu Hospital of Traditional chinese Medicine Beijing(100000)China Center for Evidence-Based and Translational Medicine Zhongnan Hospital of Wuhan UniversityWuhan(430074)China College of Acupuncture and Massage College of Health and RehabilitationNanjing University of Chinese MedicineNanjing(210023)China Department of Ophthalmology Huaihe Hospital of Henan UniversityKaifengHenan Province(475000)China ministry of Education and beijing Key Laboratory of Internal Medicine of Traditional {2. Medicine Dongzhimen Hospital of Beijing University of Traditional Chinese Medicine/Ministry of Education and Beijing Key Laboratory of Internal Medicine of Traditional Chinese MedicineBeijing(100700)China

The transformation and implementation of clinical practice guidelines for integrated traditional chinese medicine(TCM)and Western medicine(WM)is crucial to the adoption of medical science and technological findings and is an important way for TCM to be made available to the ***,clinical practice guidelines(CPGs)of TCM and WM integration in recent years was analyzed to clarify the current situation and problems in the existing guidelines according to the following four perspectives:(1)perspective of TCM and WM integration in guidelines,(2.diagnosis Using integrated TCM and WM,(3)integration of TCM and WM treatment,(4)promoting TCM and WM ***,the information and quality evaluation of CPGs for integrated chinese and Western medicine in 2.2.–2.2. were analyzed to explore the degree and methods of integration of chinese and Western medicine *** last this study aimed to lay a foundation for the further establishment of chinese characteristic,repeatable,and calculable clinical practice guidelines of TCM and WM integration.

关键词： clinical practice guidelines integrated traditional chinese and Western medicine organic integration

Pain perception enhancement in consecutive secondeye phacoemulsification cataract surgeries under topical anesthesia

在线全文

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2024年第8期17卷 1510-1518页

作者： jia-Wei Luo yan-Hua Chen jian-Feng Yu Yi-Xun Chen min ji Huai-jin Guan Eye institute Affiliated Hospital of Nantong UniversityMedical School of Nantong UniversityNantong 226001Jiangsu ProvinceChina Nantong Center for Disease Control and Prevention Nantong 226001Jiangsu ProvinceChina

Cataract is the main cause of visual impairment and blindness worldwide while the only effective cure for cataract is still *** phacoemulsification under topical anesthesia has been the routine procedure for cataract ***,patients often grumbled that they felt more painful during the second-eye surgery compared to the first-eye *** intraoperative pain experience has negative influence on satisfaction and willingness for second-eye cataract surgery of patients with bilateral *** ocular pain is a complicated process induced by the nociceptors activation in the peripheral nervous ***,neuropsychological,and pharmacological factors work together in the enhancement of intraoperative *** published literatures have focused on the pain enhancement during the secondeye phacoemulsification *** this review,we searched PubMed database for articles associated with pain perception differences between consecutive cataract surgeries published up to Feb.1,*** summarized the recent research progress in mechanisms and interventions for pain perception enhancement in consecutive secondeye phacoemulsification cataract *** review aimed to provide novel insights into strategies for improving patients’intraoperative experience in second-eye cataract surgeries.

关键词： ocular pain cataract surgery topical anesthesia intraoperative experience second-eye phacoemulsification

Sono-photocatalytic amination of quinoxalin-2.1H)-ones with aliphatic amines

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 Chemical Letters 2024年第10期35卷 269-272页

作者： Wen-Tao Ouyang Jun jiang yan-Fang jiang Ting Li Yuan-Yuan Liu Hong-Tao ji Li-Juan Ou Wei-min He School of chemistry and Chemical Engineering University of South ChinaHengyang 421001China School of Materials Science and Engineering Hunan Institute of TechnologyHengyang 421002China National Engineering Research Center of Low-Carbon Processing and Utilization of Forest Biomass Nanjing Forestry UniversityNanjing 210037China

The first example of sono-photocatalytic bond formation was *** both visible light and ultrasound wave as the energy,various 3-aminoquinoxalin-2.1H)-ones were efficiently obtained with good functional group tolerance in the absence of any additive or external *** with the conventional photocatalysis,sono-photocatalysis not only dramatically improved the reaction rates and yields,but also reduced energy consumption.

关键词： Sono-photocatalysis External photocatalyst-free Quinoxalin-2.1H)-ones Amination Aliphatic amines

Effects of acid-rock reaction on physical properties during CO_(2.-rich industrial waste gas(CO_(2.-rich IWG)injection in shale reservoirs

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2024年第1期21卷 272-285页

作者： Yi-Fan Wang jing Wang Hui-Qing Liu Xiao-Cong Lv Ze-min ji National Key Laboratory of Petroleum Resources and Engineering China University of PetroleumBeijing102249China MOE Key Laboratory of Petroleum Engineering China University of PetroleumBeijing102249China Research institute of Exploration and Development PetroChinaBeijing100083China

"Carbon peaking and carbon neutrality"is an essential national strategy,and the geological storage and utilization of CO_(2.is a hot issue ***,due to the scarcity of pure CO_(2.gas sources in China and the high cost of CO_(2.capture,CO_(2.-rich industrial waste gas(CO_(2.-rich IWG)is gradually emerging into the public's ***_(2.has good adsorption properties on shale surfaces,but acidic gases can react with shale,so the mechanism of the CO_(2.-rich IWG-water-shale reaction and the change in reservoir properties will determine the stability of geological ***,based on the mineral composition of the Longmaxi Formation shale,this study constructs a thermodynamic equilibrium model of water-rock reactions and simulates the regularity of reactions between CO_(2.-rich IWG and shale *** results indicate that CO_(2.consumed 12.after reaction,and impurity gases in the CO_(2.-rich IWG can be dissolved entirely,thus demonstrating the feasibility of treating IWG through water-rock *** IWG inhibits the dissolution of CO_(2.,the optimal composition of CO_(2.-rich IWG is 95%CO_(2.and 5%IWG when CO_(2.geological storage is the main *** contrast,when the main goal is the geological storage of total CO_(2.-rich IWG or impurity gas,the optimal CO_(2.-rich IWG composition is 50%CO_(2.and 50%*** the CO_(2.-rich IWG-water-shale reaction,temperature has less influence on the water-rock reaction,while pressure is the most important ***2.has the greatest impact on water-rock reaction in *** minerals,clay minerals such as illite and montmorillonite had a significant effect on water-rock *** overall reaction is dominated by precipitation and the volume of the rock skeleton has increased by 0.74 cm3,resulting in a decrease in shale porosity,which enhances the stability of CO_(2.geological storage to some *** the reaction between CO_(2.-rich IWG-water-shale at simulated temperatures and pressures,precipitation

关键词： CO_(2.-rich industrial waste gas Geological storage Acid-rock reaction Shale Geochemical modelling