检索结果-南通市图书馆

Regio-and Stereoselective Polymerization of Bio-based Ocimene by Rare-Earth Metal Catalysts

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 Polymer Science 2024年第2期42卷 223-229,I0008页

作者： Qi-Yuan Wang li-Peng Sang Zhen Zhang Yang Jiang Hui Tian xia Zhao xiang Guo Shi-Hui li State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China Science and Technology on Aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechonologyXiangyang441003China Shanxi Coal Chemical Industry Technology Research Institute Xi’an710000China Hubei Institute of Aerospace Chemotechonology Xiangyang441003China

Coordination polymerization of renewable β-ocimene has been investigated using asymmetric diiminophosphinate lutetium complex1, β-diketiminate yttrium complex 2, bis(phosphino)carbazolide yttrium complex 3, half-sandwich benzyl fluorenyl scandium complex 4 and pyridyl-methylene-fluorenyl rare-metal complexes 5a–5c. Complexes 1, 4 and 5a–5c show trans-1,2-regioselectivities and high activities, of which 5c exhibits excellent isoselectivity(mmmm>99%). Conversely, complexes 2 and 3 promote β-ocimene polymerization to produce isotactic cis-1,4-polyocimenes(cis-1,4>99%, mm>95%). Diblock copolymers cis-1,4-PIP-block-cis-1,4-POc and cis-1,4-PBD-block-cis-1,4-POc are obtained in one-pot reactions of β-ocimene with isoprene and butadiene using complex 3. Epoxidation and hydroxylation of polyocimene afford functionalized polyolefins with enhanced T_(g)(from-20 ℃ to 79 ℃ and 74 ℃) and hydrophilicity.

关键词： Biobased monomer Terpenes Ocimene Rare-earths Polymerization Regio/stereoselectivity Elastomer

Design method of extractant for liquid-liquid extraction based on elements and chemical bonds

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第4期68卷 193-202页

作者： Yuwen Wei Chunling Zhang Yue Zhang lili Wang li xia xiaoyan Sun Shuguang xiang Institute of Process System Engineering College of Chemical EngineeringQingdao University of Science and TechnologyQingdao 266042China Yantai Guobang Chemical Machinery Technology Co. Ltd.Yantai 264002China

In the petrochemical industry process, the relative volatility between the components to be separated is close to one or the azeotrope that systems are difficult to separate. liquid-liquid extraction is a common and effective separation method, and selecting an extraction agent is the key to extraction technology research. In this paper, a design method of extractants based on elements and chemical bonds was proposed. A knowledge-based molecular design method was adopted to pre-select elements and chemical bond groups. The molecules were automatically synthesized according to specific combination rules to avoid the problem of “combination explosion” of molecules. The target properties of the extractant were set, and the extractant meeting the requirements was selected by predicting the correlation physical properties of the generated molecules. Based on the separation performance of the extractant in liquid-liquid extraction and the relative importance of each index, the fuzzy comprehensive evaluation membership function was established, the analytic hierarchy process determined the mass ratio of each index, and the consistency test results were passed. The results of case study based on quantum chemical analysis demonstrated that effective determination of extractants for the analysis of benzene-cyclohexane systems. The results unanimously prove that the method has important theoretical significance and application value.

关键词： Molecular design Element and chemical bonds Molecular simulation Thermodynamics Solvent extraction

Investigation on occupant presence and appliance operation schedules for university campus in south China sub-tropical area

在线全文

学校读者我要写书评

暂无评论

Building Simulation 2024年第2期17卷 301-318页

作者： Siwei Lou Zhongyuan lin Yukai Zou Dawei xia Yu Huang Zhuohong li Zhaowen Gu School of Civil Engineering Guangzhou UniversityGuangzhou Higher Edu.Mega CenterGuangzhouChina School of Architecture and Urban Planning Guangzhou UniversityGuangzhou Higher Edu.Mega CenterGuangzhouChina

Building occupant presence during varying periods is crucial to the performance studies of buildings and city ***,the understanding of the building occupancies on the university campus remains *** address this gap,our study employs field measurements,payment records,course arrangements,and building access systems to depict the occupancy patterns of the canteen,dormitory,library,and teaching and lab buildings during weekdays and *** found that the occupancy rates across different buildings are somehow interrelated,given that the total number of occupants on campus is generally ***,dormitory occupancy rates tend to be low during the morning and afternoon course hours,which inversely correlates with the high occupancy rates in the teaching and lab buildings during these ***,canteens experience surges in occupancy during meal times,which coincide with a decrease in library ***,we established appliance operation schedules for dormitories through surveys and on-site *** dispensers and electronic devices were identified as the primary energy consumers for both male and female occupants,with desk-top fans and hairdryers being significant energy users for male and female occupants,*** findings are essential for energy studies within a campus setting,underlining the importance of considering occupant behaviors on a regional scale.

关键词： building occupant behavior university campus occupancy schedule appliance operation schedule

Immune landscape and response to oncolytic virus-based immunotherapy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Medicine 2024年第3期18卷 411-429页

作者： Chaolong lin Wenzhong Teng Yang Tian Shaopeng li Ningshao xia Chenghao Huang State Key Laboratory of Vaccines for Infectious Diseases Xiang An Biomedicine LaboratoryDepartment of Laboratory MedicineSchool of Public HealthXiamen UniversityXiamen361102China National Institute of Diagnostics and Vaccine Development in Infectious Diseases State Key Laboratory of Molecular Vaccinology and Molecular DiagnosticsXiamen UniversityXiamen361102China

Oncolytic virus(OV)-based immunotherapy has emerged as a promising strategy for cancer treatment,offering a unique potential to selectively target malignant cells while sparing normal ***,the immunosuppressive nature of tumor microenvironment(TME)poses a substantial hurdle to the development of OVs as effective immunotherapeutic agents,as it restricts the activation and recruitment of immune *** review elucidates the potential of OV-based immunotherapy in modulating the immune landscape within the TME to overcome immune resistance and enhance antitumor immune *** examine the role of OVs in targeting specific immune cell populations,including dendritic cells,T cells,natural killer cells,and macrophages,and their ability to alter the TME by inhibiting angiogenesis and reducing tumor ***,we explore strategies to optimize OV-based drug delivery and improve the efficiency of OV-mediated *** conclusion,this review offers a concise and comprehensive synopsis of the current status and future prospects of OV-based immunotherapy,underscoring its remarkable potential as an effective immunotherapeutic agent for cancer treatment.

关键词： oncolytic virus immunotherapy immunotherapeutic agents immune landscape

Comparison of Statistical Signal Detection Methods in Adverse Events Following Immunization — China, 2011–2015

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China CDC weekly 2024年第16期6卷 350-356,I0001页

作者： Lanfang xia Keli li Yan li Zhijie An Quanwei Song Lei Wang Zundong Yin Huaqing Wang National Key Laboratory of Intelligent Tracking and Forecasting for Infectious Diseases(NITFID) BeijingChina National Immunization Program Chinese Center for Disease Control and PreventionBeijingChina

Introduction:The current study aims to assess the performance of data mining techniques in detecting safety signals for adverse events following immunization(AEFI)using routinely obtained data in *** different methods for detecting vaccine safety signals were ***:The AEFI data from 2011 to 2015 was collected for our *** analyzed the data using four different methods to detect signals:the proportional reporting ratio(PRR),reporting odds ratio(ROR),Bayesian confidence propagation neural network(BCPNN),and multi-item gamma Poisson shrinker(MGPS).Each method was evaluated at 1–3 thresholds for *** assess the performance of these methods,we used the published signal rates as gold standards to determine the sensitivity and ***:The number of identified signals varied from 602 for PRR1(with a threshold of 1)to 127 for *** considering the common reactions as the reference standard,the sensitivity ranged from 0.9%for MGPS1/2 to 38.2%for PRR1/2,and the specificity ranged from 85.2%for PRR1 and ROR1 to 96.7%for *** considering the rare reactions as the reference standard,PRR1,PRR2,ROR1,ROR2,and BCPNN exhibited the highest sensitivity(73.3%),while MGPS1 exhibited the highest specificity(96.9%).Discussion:For common reactions,the sensitivities were modest and the specificities were *** rare reactions,both the sensitivities and specificities were *** study provides valuable insights into the selection of signal detection methods and thresholds for AEFI data in China.

关键词： specificity routine vaccine

Numerical and theoretical study of large-scale failure of strata overlying sublevel caving mines with steeply dipping discontinuities

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1799-1815页

作者： Kaizong xia Zhiwei Si Congxin Chen xiaoshuang li Junpeng Zou Jiahao Yuan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China School of Urban Construction Changzhou UniversityChangzhou 213164China Faculty of Engineering China University of Geosciences(Wuhan)Wuhan 430074China

The deformation and fracture evolution mechanisms of the strata overlying mines mined using sublevel caving were studied via numerical ***,an expression for the normal force acting on the side face of a steeply dipping superimposed cantilever beam in the surrounding rock was deduced based on limit equilibrium *** results show the following:(1)surface displacement above metal mines with steeply dipping discontinuities shows significant step characteristics,and(2)the behavior of the strata as they fail exhibits superimposition ***,failure first occurs in certain superimposed strata slightly far from the ***,with the constant downward excavation of the orebody,the superimposed strata become damaged both upwards away from and downwards toward the *** process continues until the deep part of the steeply dipping superimposed strata forms a large-scale deep fracture plane that connects with the *** deep fracture plane generally makes an angle of 12°-20°with the normal to the steeply dipping *** effect of the constant outward transfer of strata movement due to the constant outward failure of the superimposed strata in the metal mines with steeply dipping discontinuities causes the scope of the strata movement in these mines to be larger than *** strata in the metal mines with steeply dipping discontinuities mainly show flexural toppling ***,the steeply dipping structural strata near the goaf mainly exhibit shear slipping failure,in which case the mechanical model used to describe them can be simplified by treating them as steeply dipping superimposed cantilever *** taking the steeply dipping superimposed cantilever beam that first experiences failure as the key stratum,the failure scope of the strata(and criteria for the stability of metal mines with steeply dipping discontinuities mined using sublevel caving)can be obtained via iterative computations from the ke

关键词： sublevel caving mines universal distinct element code(UDEC)numerical approach large-scale ground movement steeply dipping superimposed cantilever beam toppling failure

Construction of multifunctional lanthanum manganese mixed nanoparticles mediated by ionic liquids for selective aerobic oxidation of cyclohexane

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第5期43卷 2205-2221页

作者： Hao li Rui-Rui Zhang Ke-Xin li Shuang Wei Yu-Mei liu Rui-xia liu Beijing Key Laboratory of Ionic liquids Clean Process CAS Key Laboratory of Green Process and EngineeringState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Selective oxidation of alkanes to produce highvalue chemicals is an essential strategy and means to realize efficient utilization of *** this work,a strategy of lanthanum manganese mixed metal oxides(LMMO)regulated via a facile ionic liquid(IL)-assisted hydrothermal method was proposed to construct the multifunctional catalysts,which exhibited excellent catalytic performance in the selective aerobic oxidation of *** 8.9%cyclohexane conversion with 90%KA oi(cyclohexanol and cyclohexanone)selectivity was achieved over the optimal LMMO catalyst under mild *** effects of anion type,carbon chain length and concentration of ILs on the structure and properties of catalysts were investigated through various characterizations,indicating the structure-directing and template effect of ILs on the multifunctional *** formation of self-assembled spherical nanoparticles followed the"dissolution-nucleation-proliferation"mechanism with the introduction of 1-butyl-3-methylimidazolium hydrogen sulfate,ascribing the synergistic effect between the microenvironment of ILs and the hydrothermal ***,the high reactive oxygen concentration redox capacity,and suitable basic sites of LMMO catalysts mediated by ILs enhance the activation of C-H bonds and molecular oxygen,simultaneously influencing the adsorption and desorption of the substrate.A comprehensive understanding of the high KA oil selectivity and radical reaction mechanism was elucidated based on in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and radical trapping *** recycling and regeneration experiments further illuminated that the removal of adsorbed cyclohexanone acting on the LMMO catalyst was the key to achieve high KA oil selectivity.

关键词： Ionic liquids Nanoparticle Multifunctional catalyst Cyclohexane oxidation

Effect of yttrium on catalytic performance of Y-doped TiO_(2) catalysts for propane dehydrogenation

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第5期42卷 962-971,I0005页

作者： liyu Hou liming xia Ruipeng Zhou Jianmei li Renjie li Zhen Zhao Guimei Yuan Aijun Duan State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Institute of Catalysis for Energy and Environment College of Chemistry and Chemical EngineeringShenyang Normal UniversityShenyang110034China

Defective bulk catalysts based on TiO_(2) have superior catalytic performance for propane dehydrogenation(PDH).The oxygen vacancy concentration and the number of active sites on the catalyst surface can be effectively tuned by doping metal in TiO_(2).Herein,yttrium(Y)-doped titanium dioxide(nY/TiO_(x))catalysts were in-situ synthesized via the coprecipitation method to study the effect of rare earth metal Y doping on the structure of TiO_(2) and the catalytic performance for *** results demonstrate that Ydoped TiO_(2) exhibits higher catalytic activity,propylene selectivity and stability than bare TiO_(2).Full characterizations with X-ray diffraction(XRD),high-resolution transmission electron microscope(HRTEM),X-ray photoelectron spectroscopy(XPS),infrared spectroscopy of pyridine adsorption(Py-IR),temperature-programmed desorption of ammonia(NH_(3)-TPD),H_(2) temperature-programmed reduction(H_2-TPR),and Raman techniques on these catalysts reveal that Y^(3+)can enter TiO_(2) lattice,and the lattice stability of the catalyst can be enhanced by replacing Ti^(4+)to form Y-O-Ti ***,the introduction of an appropriate amount of Y can obviously promote the PDH reaction by adjusting the acidity of the catalyst,improving the release capacity of TiO_(2) lattice oxygen and increasing the formation of active ***,excessive Y doping will lead to pore clogging,and the exposure of active sites will be reduced,resulting in the degradation of catalytic performance.

关键词： Propane dehydrogenation Anatase Lattice defects Coordinatively unsaturated Ti cations Oxygen vacancy Rare earths

Spatiotemporal changes in sunshine duration and its influential factors in Chongqing,China from 1961 to 2020

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第6期21卷 2005-2024页

作者： li Jun xia hongxuan JIANG Jinge XU Weifeng WEN Di XU Junfeng College of Geography and Tourism Chongqing Normal UniversityChongqing 401331China Key Laboratory of GIS Application of Chongqing Chongqing 401331China Chongqing Key Laboratory of Earth Surface Processes and Environmental Remote Sensing in Three Gorges Reservoir area Chongqing 401331China Institute of Remote Sensing and Earth Sciences School of Institute of Remote Sensing and Earth SciencesSchool of ScienceHangzhou Normal UniversityHangzhou 311121China

The surface solar radiation in most parts of the world has undergone a phenomenon known as global dimming and brightening,characterized by an initial decrease followed by an *** a result,the sunshine duration(SD)has decreased in the past 60 *** the backdrop of global dimming and brightening,SD has decreased to varying degrees in many regions of *** the observed data of SD,cloud amount(total cloud amount and low cloud amount,abbreviated as TCA and LCA),precipitation,and relative humidity(RH)from 34 meteorological stations in Chongqing during the period of 1961-2020,along with a digital elevation model(DEM)with a resolution of 90 m,this study analyzed the spatiotemporal variations and influencing factors of *** analysis employed methods such as linear regression,Mann-Kendall test,wavelet transformation,and DEM-based possible SD distributed *** results showed that the annual SD in Chongqing has significantly decreased over the last 60 years,with a decreasing interannual trend rate(ITR)of 40.4 h/*** for no obvious trend in spring,SD decreased significantly in summer,autumn and winter at the ITR of 21.1 h/10a,8.5 h/10a and 7.5 h/10a,*** abrupt decrease in the annual SD was found in *** difference before and after the abrupt decrease was 177.7 *** difference before and after the abrupt decrease was 177.7 *** annual SD possessed the oscillation period of *** spatial heterogeneity of the mean annual SD during the last 60 years was *** distribution of SD in Chongqing is high in the northeast and low in the *** addition,about 73%of the total area in Chongqing showed a significant and very significant decreasing *** regions with significant changes are mainly concentrated in the regions with altitudes of 200~1000 *** increasing LCA was the main cause of the decrease of the annual SD in the regions with 200-400 m altitude decreased the most and changed the *** LCA is the prim

关键词： Sunshine duration Spatiotemporal changes Mann-Kendall test Wavelet analysis Geodetector model