检索结果-南通市图书馆

Chinese Chemical Letters 2023年第1期34卷 440-445页

作者： Conghao Ku Huiqin Guo Kexin Li Qiong Wu Liushui Yan Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle Nanchang Hangkong UniversityNanchang 330063China National-Local Joint Engineering Research Center of Heavy Metals Pollutants Control and Resource utilization Nanchang Hangkong UniversityNanchang 330063China Jiangxi Provincial Experimental Teaching Demonstration Center of Environmental Science and Engineering Nanchang Hangkong UniversityNanchang 330063China

Photocatalytic selective transform native lignin into valuable chemicals is an attractive but challenging ***,we report a mesoporous sulfur-doped carbon nitride(MSCN-0.5)which is prepared by a facile one-step thermal condensation *** is highly active and selective for the cleavage Cα-Cβbond inβ-O-4 lignin model compound under visible light radiation at room temperature,achieving 99%substrate conversion and 98%Cα-Cβbond cleavage *** studies revealed that the Cβ-H bond of lignin model compounds activated by holes and generate key Cβradical intermediates,further induced the Cα-Cβbond cleavage by superoxide anion radicals(·O2-)to produce aromatic *** Camellia oleifera shell(WCOS)was taken as a representative to further understand the reaction mechanisms on native lignin.33.2 mg of monophenolic compounds(Vanillin accounted for 22%and Syringaldehyde for 34%)can be obtained by each gram of WCOS lignin,which is 2.5 times as that of the pristine carbon *** present work offers useful guidance for designing metal-free heterogeneous photocatalysts for Cα-Cβbond cleavage to harvest monophenolic compounds.

关键词： mesostructure Sulfur-doped carbon nitride Photocatalysis Lignin model compound Native lignin Monophenolic compounds

Flexibility in DUT-8(Cu)Metal-Organic Framework:Impact of Cluster,Stress,History,and Hierarchical Texture

在线全文

学校读者我要写书评

暂无评论

CCS Chemistry 2023年第10期5卷 2225-2236页

作者： Mariia Maliuta Irena Senkovska Vitaliy Romaka Mariia Roslova Zhehao Huang Petko Petkov Volodymyr Bon Stefan Kaskel Chair of Inorganic Chemistry I Technische Universität DresdenD-01069 Dresden Leibniz Institute for Solid State Research(IFW Dresden) 01069 Dresden Department of Materials and Environmental Chemistry Stockholm UniversitySE-10691 Stockholm Faculty of Chemistry and Pharmacy Department of Organic Chemistry and PharmacognosySofia University“St.Kl.Ohridski”1164 Sofia

The flexibility of metal-organic frameworks(MOFs)featuring stimuli-responsive structural transitions is often governed not only by the chemical composition and topology but also by orthogonal factors such as particle size,desolvation method,and history of the sample.A precise understanding of the mechanism behind such observations has been lacking up to now,and there are still substantial open questions concerning the impact of sample treatment *** DUT-8(M)family([M_(2)(2,6-ndc)2(dabco)]n,2,6-ndc=2,6-naphthalene dicarboxylate,dabco=1,4-diazabicyclo-[2.2.2]-octane),encompasses isostructural compounds based on Ni,Zn,Co,and Cu in the cluster node and is representative of pillared layer MOFs,often showing flexible *** this contribution,we discuss a possible explanation for the differences in flexibility observed in desolvated phases of DUT-8(Cu).Theoretical calculations and crystallographic data shed light on the preferred formation of interpenetrated confined closed pore phases in DUT-8(Cu)in contrast to DUT-8(Ni,Co,Zn)where the closed pore phases are formed.

关键词： pillared layer metal-organic frameworks flexible behavior phase transition mesostructure texture gas adsorption

Molecular pore-wall engineering of mesozeolitic conjugated polymers for photoredox hydrogen production with visible light

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 Energy Chemistry 2017年第1期26卷 87-92页

作者： Mingwen Zhang Jinshui Zhang Yan Chen Xinchen Wang State Key Laboratory of Photocatalysis on Energy and Environment College of ChemistryFuzhou UniversityFuzhou 350002FujianChina

A chemical protocol based on molecular engineering of polymeric matrix is developed for the chemical optimization of ordered mesoporous carbon nitride (OMCN) in this study to address the concerns on the serious nanostructure-induced semiconductive defects, in particular the remarkable hypsochromic shift of absorption threshold and the increased excition dissociation energy. Physical characterizations demonstrate that the successful incorporation of 3-aminothiophene-2-carbonitrile (ATCN) aromatic donor in OMCN matrix can efficiently extend the pi-conjugated system, red-shift the optical absorption toward longer wavelengths and promote exciton splitting, thus well overcoming the serious semiconductive defects. In addition, the unique structural benefits of OMCN, such as the well-orientated nanoarchitectures with large specific surface area and uniform nanosized pore, have been well remained in ATCN-modified sample (OMCNA) via adjusting the ATCN/cyanamide molar ratio to minimize the unavoidable matrix disturbance. Hence, an obviously enhanced photocatalytic activity toward H-2 evolution and selective oxidation of alcohols are obtained on optimized OMCNA samples, greatly underlining the advantage of molecular engineering in supporting nanostructured photocatalysts. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.

关键词： Photocatalysis Graphitic carbon nitride Polymers mesostructure Water splitting

Preparation of Mesoporous Nano-Hydroxyapatite Using a Surfactant Template Method for Protein Delivery

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2012年第2期9卷 224-233页

作者： Xiaodong Wu Xiaofeng Song Dongsong Li Jianguo Liu Peibiao Zhang Xuesi Chen Department of Bone and Joint Surgery First Hospital of Jilin UniversityChangchun 130021P R.China Key Laboratory of Polymer Ecobiomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangehun 130022P.R.China

Mesoporous nano-hydroxyapatite （n-HA） has gained more and more attention as drug storage and release hosts. The aim of this study is to observe the effect of the ratio of surfactant to the theoretical yield of HA on the mesoporous n-HA, then to reveal the effect of the mesoporous nanostructure on protein delivery. The mesoporous n-HA was synthesized using the wet precipitation in the presence of cetyltrimethylammonium bromide （CTAB） at ambient temperature and normal atmospheric pressure. The morphology, size, crystalline phase, chemical composition and textural characteristics of the product were well characterized by X-ray Powder Diffraction （XRD）, Fourier Transform Infrared Spectroscopy （FTIR）, Scanning Electron Microscopy （SEM）, Transmission Electron Microscopy （TEM）, Dynamic Light Scattering （DLS） and N2 adsorption/desorption, respectively. The protein adsorption/release studies were also carried out by using Bovine Serum Albumin （BSA） as a model protein. The results reveal that the mesoporous n-HA synthesized with CTAB exhibits high pure phase, low crystallinity and the typical characteristics of the mesostructure. The BSA loading increases with the specific surface area and the pore volume of n-HA, and the release rates of BSA are different due to their different pore sizes and pore structures, n-HA synthesized with 0.5% CTAB has the highest BSA loading and the slowest release rate because of its highest surface area and smaller pore size. These mesoporous n-HA materials demonstrate a potential application in the field of protein delivery due to their bioactive, biocompatible and mesoporous properties.

关键词： hydroxyapatite nanoparticles mesostructure cetyltrimethylammonium bromide drug delivery

Interrelationships between Deformation and Metamorphic Events across the Western Hinterland Zone, NW Pakistan

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 Earth Science 2016年第4期27卷 584-598页

作者： Asghar Ali Mustafa Yar Muhammad Asif Khan Shah Faisal Department of Geology University of Peshawar Department of Earth and Environmental Sciences Bahria University National Centre of Excellence in Geology University of Peshawar Earth and Environmental Sciences IKBAS University of British Columbia

Microscopic to mesoscopic structural investigations and foliation intersection axes（FIAs） preserved in porphyroblasts reveal a very complex history of deformation and tectonism within the southwestern part of the western hinterland zone along the northern margin of the Indian plate, NW Pakistan. D_1, D_2, and D_3 related structures in the southwestern part resemble the F_1/F_2, F_3, and F_4 related structures in the northeastern part of the western hinterland zone. These structures developed at the same time through the same changes in the direction of bulk shortening in southwestern and northeastern parts of the western hinterland zone. FIA set 1 indicates NW-SE shortening. The D_2 fabrics, mineral lineations and fold axes indicate E-W shortening. FIA set 2, D_3 fold axes and mineral lineations indicate NNE-SSW shortening. D_3 deformation event is equivalent to the F_4 deformation event in the northeastern part of the western hinterland zone. D_4 fold axes, mineral stretching lineations and axial plane foliation suggest ENE-WSW shortening. The D_4 NNW-SSE fabrics, which formed in the region after the formation of the MMT（main mantle thrust）, Khairabad-Panjal thrust fault, Hissartang thrust fault and MBT（main boundary thrust）, likely resulted from ENE-WSW bulk shortening related to development of the Hazara-Kashmir syntaxis.

关键词： FIA western hinterland zone microstructure mesostructure metamorphism tectonics,NW Pakistan.

Numerical Simulation of Failure Process of Concrete Under Compression Based on Mesoscopic Discrete Element Model

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2008年第S1期13卷 19-25页

作者：王卓琳林峰顾祥林 Department of Building Engineering Tongji University

A two-dimensional mesoscopic numerical method to simulate the failure process of concrete under compression was developed based on the discrete element method by modifying the rigid body-spring model proposed by Nagai et al. In the calculation model, aggregates or aggregate elements inside the concrete were simplified as rigid bodies with regular polygon profiles, which were surrounded by mortar polygons or mortar elements. All of the adjacent elements were connected by springs. According to the random distribution of aggregates, the mesh was generated by using Voronoi diagram method. Plastic behavior after the elastic limit for a spring was considered to set up the constitutive model of the spring, and Mohr-Coulomb criterion was adopted to judge the failure of a spring. Simulation examples show that the proposed method can be used to predict the mechanical behavior of concrete under compression descriptively and quantitatively both for small deformation problems and for larger deformation problems.

关键词： concrete mesostructure discrete element method (DEM) numerical simulation