检索结果-南通市图书馆

Nano Research 2024年第6期17卷 4994-5001页

作者： Xitong ren Jiajie Sun Yusen Li Feng Bai Key Laboratory for Special Functional Materials of Ministry of Education National and Local Joint Engineering Research Center for High-Efficiency Display and Lighting TechnologySchool of Materials Science and Engineeringand Collaborative Innovation Center of Nano Functional Materials and ApplicationsHenan UniversityKaifeng 475004China School of physics and Electronics Henan UniversityKaifeng 475004China

The combination of donor-acceptor(D-A)structures presents a viable strategy for fabricating covalent organic frameworks(COFs)with exceptional photocatalytic ***,the selection of functional groups on donor or acceptor building blocks and their effect on the macroscopic properties of COFs are *** this study,we tactfully synthesized a pair of Py-DBT-COFs from the same pyrene(Py)donor and 4,7-diphenylbenzo[c][1,2.5]thiadiazole(DBT)acceptor cores with distinct primitive functional *** primitive functional groups of building units determine the photocatalytic properties of corresponding ***,Py-C-DBT-COF synthesized from Py-4CHO and DBT-2.H_(2.showcases a splendid H_(2.evolution rate as high as 2.,377.7μmol/(g·h)(with 5 wt.%Pt)originating from better charge transfer capacity,which is significantly superior to that of Py-N-DBT-COF constructed from Py-4NH_(2.and *** distinct photocatalytic performances of the two COFs are demonstrated to originate from the different charge separation and transfer *** work supplies a new avenue for optimizing the photocatalytic performance of D-A COFs from the perspective of primitive functional group selections.

关键词： covalent organic frameworks functional group donor-acceptor photocatalysis

Microstructure and Wear Resistance Evolution of HVOFSprayed WC-(W,Cr)_2.-ni Coating with Post Heat Treatment In Air Atmosphere

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

稀有金属材料与工程 2012年第S1期41卷 388-393页

作者： Hou Guoliang1,2.Zhou Huidi1,An Yulong1,2.Liu Guang1,2.Chen Jianmin1,Chen Jie1,2.1 State Key Laboratory of Solid Lubrication,Lanzhou Institute of Chemical physics,Chinese Academy of Sciences,Lanzhou 730000,China 2.Graduate university,Chinese Academy of Sciences,Beijing 100049,China Chinese Acad Sci Lanzhou Inst Chem Phys State Key Lab Solid Lubricat Lanzhou 730000 Peoples R China Chinese Acad Sci Grad Univ Beijing 100049 Peoples R China

WC-(W,Cr)2.-ni coating was prepared on 1Cr18ni9Ti stainless steel and C-2.6 ni-base Hastelloy by high velocity oxy-fuel(HVOF)*** effect of post heat treatment in air atmosphere on the microstructure,phase composition,microhardness,fracture toughness,and wear resistance of HVOF-sprayed WC-(W,Cr)2.-ni coating was *** microstructure and phase composition of the coatings were analyzed by means of field emission scanning electron microscopy(FESEM)and X-ray diffraction(XRD).The microhardness and fracture toughness of the coatings were measured using a microhardness tester and a Vickers hardness ***,dry friction and wear behavior of the coatings sliding against Si3N4 ball was investigated using an oscillating friction and wear tester;and the worn surfaces of the coatings were analyzed by means of scanning electron microscopy(SEM).It was found that heat treatment within 500-800°C resulted in crystallization of amorphous phase in as-sprayed coating,generating nanoscale new phases such as niWO4,CrWO4 and ***,heat treatment led to increase of the microhardness of as-sprayed coating,and the highest microhardness was obtained after heat treatment at 800°*** fracture toughness and wear resistance of the as-sprayed coating increased with increasing heat treatment temperature up to 700°C but tended to decrease with further elevating *** other words,the mechanical properties and wear resistance of the as-sprayed coatings were worsened owing to excessive growth of oxidation grains and depletion of ductile ni binder after heat treatment above 700°*** it was suggested that as-sprayed ceramic composite coating should be post heat treated in air at a moderate temperature of 700°C so as to achieve the optimized mechanical properties and wear resistance.

关键词： HVOF WC-(W,Cr)2.-ni coating post heat treatment microstructure wear resistance

Cucurbit[8]uril-regulated face-to-face dimerization assembly enhanced photosensitization and photocatalysis

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2024年第5期67卷 1605-1612页

作者： Haigen nie Die Hu Zhiyao Zeng Yan Fan Yaxin Zhai Xin-Long ni Key Laboratory of Chemical Biology and Traditional Chinese Medicine Ministry of Educational of ChinaKey Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan ProvinceCollege of Chemistry and Chemical EngineeringHunan Normal UniversityChangsha 410081China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of PhysicsHunan Normal UniversityChangsha 410081China

In water, N,N′-diarylpyridinium thiazolo[5,4-d]thiazole guests(G1–G3) were encapsulated by cucurbit[8]uril(Q[8]) to construct Q[8]_(3)/G_(2. complexes, in which the encapsulated G molecules exist as an exact face-to-face dimer. These complexation behaviors have been indicated by proton nuclear magnetic resonance(~1H NMR) spectroscopy and isothermal titration calorimetry(ITC),and have been confirmed by X-ray single crystal structural analysis of Q[8]_(3)/G2.(2.. While free guests G1–G3 have no ability to sensitize singlet oxygen, they all become effective singlet oxygen sensitizers when complexed with Q[8]. By irradiation of white light, Q[8]_(3)/G_(2. complexes induced selective oxidation of aryl sulfide to aryl sulfoxide in good yields and selective oxidation of dimethyl sulfide(DMS) to dimethyl sulfoxide(DMSO) in excellent yields without over-oxidation to dimethyl sulfone(DMSO_(2.)even for elongated irradiation. High-yield photo-oxidation of DMS to DMSO_(2. was only achieved by irradiation of blue light in the presence of Q[8]_(3)/G1_(2., which was also effective in photobleaching of Rhodamine B in water. The higher photo-oxidation power of Q[8]_(3)/G1_(2. has been ascribed to an additional generation of reactive oxygen species besides singlet oxygen.

关键词： host-guest interaction dimerization macrocycles photosensitization

Quintom cosmology and modified gravity after DESI 2.2.

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2024年第17期69卷 2698-2704页

作者： Yuhang Yang Xin ren Qingqing Wang Zhiyu Lu dongdong Zhang Yi-Fu Cai Emmanuel N.Saridakis department of Astronomy School of Physical SciencesUniversity of Science and Technology of ChinaHefei 230026China CAS Key Laboratory for Researches in Galaxies and Cosmology School of Astronomy and Space ScienceUniversity of Science and Technology of ChinaHefei 230026China Deep Space Exploration Laboratory Hefei 230088China department of physics Tokyo Institute of TechnologyTokyo 152-8551Japan Kavli IPMU(WPI) UTIASThe University of TokyoChiba 277-8583Japan National Observatory of Athens Lofos Nymfon 11852Greece Departamento de Matemáticas Universidad Católica del NorteAntofagasta 1270398Chile

We reconstruct the cosmological background evolution under the scenario of dynamical dark energy through the Gaussian process approach,using the latest Dark Energy Spectroscopic Instrument(DESI)baryon acoustic oscillations(BAO)combined with other *** results reveal that the reconstructed dark-energy equation-of-state(EoS)parameter w(z)exhibits the so-called quintom-B behavior,crossing-1 from phantom to quintessence regime as the universe *** investigate under what situation this type of evolution could be achieved from the perspectives of field theories and modified *** particular,we reconstruct the corresponding actions for f(R),f(T),and f(Q)gravity,*** explicitly show that,certain modified gravity can exhibit the quintom dynamics and fit the recent DESI data efficiently,and for all cases the quadratic deviation from theΛCDM scenario is mildly favored.

关键词： DESI Dark energy Quintom cosmology Modified gravity

Maps Preserving Semi-Fredholm Operators with Fixed Nullity

在线全文

学校读者我要写书评

暂无评论

Journal of Mathematical Research with Applications 2024年第4期44卷 533-540页

作者： Mengran ni Weijuan SHI department of Mathematics Shaanxi Normal University

Let X be an infinite-dimensional complex Banach space, and B(X) the algebra of all bounded linear operators on X. Given an integer n ≥ 1, we characterize all the bijective maps on B(X) preserving the difference of se... 详细信息

关键词： operator algebra adjacency preserver map semi-Fredholm operator

Approaches to improving critical current density of YBCO superconducting thick films deposited by electrophoresis

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(physics,Mechanics & Astronomy) 2004年第2期47卷 165-172页

作者： ZHU Yabin1,2. ZHOU Yueliang2. LIU Zhen2. WANG Shufang2. CHEN Zhenghao2. L?Huibin2. YANG Guozhen2. XIAO Ling3, ren Hongtao3, JIAO Yulei3 & ZHENG Minghui3 1. department of {2., College of Science, Beijing Jiaotong {2., Beijing 100044, China 2. Laboratory of Optical {2., Institute of {2. and Center for Condensed Matter {2., Chinese Academy of Sciences, Beijing 100080, China 3. General Research Institute for Nonferrous Metals, Beijing 100088, China Correspondence should be addressed to Zhu Yabin (email: ybzhu@***) 1. department of physics College of Science Beijing Jiaotong University 100044 Beijing China 2. Laboratory of Optical physics Institute of physics and Center for Condensed Matter physics Chinese Academy of Sciences 100080 Beijing China 3. General Research Institute for Nonferrous Metals 100088 Beijing China

Fabrication of YBCO superconducting thick films by electrophoresis has been widely reported. However, the value of critical current density (J c) is far from what the practical application requires. The superconducting thick films are obtained using top-seeded melt growth method with different proportional Y2.aCuO5 (Y2.1) addition. High-pressure oxygen has been used in the annealing process to improve the u{2.formity of the oxygen content in the superconducting thick films. When 40mol% Y2.1 powder is added to the YBa2.u3O7–5 (Y12.) powder,J c for the superconducting thick film by approaches described above reaches 7.008×103 A/cm2.(77 K, 0 T), which is greater than the value ever reported.

关键词： YBCO thick films, electrophoretic deposition, melt-textured.

Transfer relation between subgrade frost heave and slab track deformation and vehicle dynamic response in seasonally frozen ground

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang university-Science A(Applied physics & Engineering) 2024年第2期25卷 130-146页

作者： Juanjuan ren Junhong DU Kaiyao ZHANG Bin YAN Jincheng TIAN MOE Key Laboratory of High-speed Railway Engineering Southwest Jiaotong UniversityChengdu610031China School of Civil Engineering Southwest Jiaotong UniversityChengdu610031China School of Civil Engineering Central South UniversityChangsha410075China Airport Planning and Design Institute POWERCHINA Kunming Engineering Corporation LimitedKunming650051China

Subgrade frost heave in seasonally frozen ground can greatly influence the safety and smooth running of high-speed trains and the service performance of track *** this study,we used a static model to:(1)investigate track-subgrade frost heave and develop a dynamic model of vehicle-track-subgrade frost heave;(2.explore the transfer relation between subgrade frost heave and track structure deformation;(3)examine the characteristics of interlayer debonding;(4)study the influence of subgrade frost heave on the dynamic response of vehicles in high-speed railways in seasonally frozen regions.A Fourier series was used to fit the frost heave waveform and simulate the behavior of subgrade uneven frost heave using data collected *** results show:(i)The position of frost heave significantly affects the transfer of deformation to a slab *** largest deformation of the track slab,with the amplitude transfer ratio reaching 2.%,was recorded when the frost heave occurred near the joint of the base plate.(ii)At the same frost heave amplitude,long-wave frost heave causes smaller deformation and debonding of the track structure than short-wave frost *** the wavelength range of 10-30 m,the main frequency of the acceleration spectral density was concentrated between 3.5 and 3.7 Hz,with larger frost heave wavelengths producing smaller superposition on the vertical acceleration of the vehicle.(ii)The maximum wheel-rail force occurs when the front bogie passes the frost heave peak,with greater frost heave amplitudes producing greater wheel-rail *** these results,we conclude there is a clear need to control the frost heave deformation of the track to reduce the dynamic response of the vehicle and in turn improve train operatSubgrade frost heave in seasonally frozen ground can greatly influence the safety and smooth running of high-speed trains and the service performance of track *** this study,we used a static model to:(1)investigate track`-subgr

关键词： Slab track Subgrade frost heave Transfer relation Vehicle-track-subgrade coupling Dynamic response

Compression behavior of Zr_(41)Ti_(14)Cu_(12.5)ni_(10)Be_(2..5) bulk metallic glass up to 2. GPa

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

Science China(physics,Mechanics & Astronomy) 2005年第3期48卷 319-324页

作者： LI Gong 1, 2., ZHAN Zaiji 2., LIU Jing 3 , YUN Jinku 1 , SUN Liling 2., LIU Riping 1 , ZHANG Jun 2.& WANG Wenkui 1, 2.1. Key Laboratory of Metastable Materials Science and Technology, Yanshan university, Qinhuangdao 066004, China 2. Center for Condensed Matter {2., Institute of {2., Chinese Academy of Sciences, Beijing 100080, China 3. BSRF, Institute of High Energy {2., Chinese Academy of Sciences, Beijing 100039, China 1. Key Laboratory of Metastable Materials Science and Technology Yanshan University 066004 Qinhuangdao China 2. Center for Condensed Matter physics Institute of Physics Chinese Academy of Sciences 100080 Beijing China 3. BSRF Institute of High Energy Physics Chinese Academy of Sciences 100039 Beijing China

The compression of a Zr41Ti14Cu12.5ni10Be2..5 bulk metallic glass (BMG) is investigated at room temperature up to 2. GPa using in-situ high pressure energy dispersive X-ray diffraction with a synchrotron radiation source. The pressure-induced structural relaxation is exhibited. It is found that below about 8 GPa, the existence of excess free volume contributes to the rapid structural relaxation, which gives rise to the rapid volumetric change, and the structural relaxation results in the structural stiffness under higher pressure.

关键词： bulk metallic glass, high pressure, structural relaxation, synchrotron radiation.

Status of Theoretical Study on Superheavy Nuclei

在线全文

学校读者我要写书评

暂无评论

Status of Theoretical Study on Superheavy Nuclei

Diamond synthesis from a system of chromium-carbide andni_(70)Mn_(2.)Co_5 alloy

CCAST“放射性束物理”研讨会

作者： zhongzhou ren(1) {2. of {2., nanjing university, nanjing 2.0008, P. R. China (2. Center of Theoretical Nuclear {2., Institute of Modern {2., Lanzhou 730000, P. R.China

＜正＞At first I will briefly review the new experimental progress of superheavy *** I willtalk about theoretical studies on superheavy *** is mainly on the structure of *** upper limit and a lower limit for the binding energy of superheavy nuclei areestablished based on the relativistic mean-field *** is useful for future calculationsof the cross-section to synthesize a new superheavy *** is also helpful to *** of alpha decay for a unknown superheavy *** some suggestions areproposed in order to speed up the progress of study on superheavy nuclei in China.

关键词： superheavy elements alpha-decay energies lifetimes name of future new element: Chinium (Cn).

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第24期43卷 2063-2066页

作者： LI Liangbin 1, JIANG Jinchun 1, HONG Shiming 1, ZHONG Yumao 2.and ZHANG Xinyuan 2.1. Institute of Applied physics, Sichuan Union {2., Chengdu 610065, China 2. Center for Analysis and Test, Sichuan Union {2., Chengdu 610065, China Institute of Applied physics Sichuan Union University Chengdu China Center for Analysis and Test Sichuan Union University Chengdu China

In order to ascertain the mechanism of interaction between carbide and metallic catalyst and formation of diamond under high pressure and high temperature, and find a new method to synthesize diamond with special properties, it is necessary to investigate the reaction behavior of different carbides and metallic solvent_catalysts under high pressure and high temperature. A system of Cr-3C-2.powder and ni 70Mn 2.Co 5 alloy in weight ratio of 1∶6 was treated under 6 0 GPa and 1 500℃ for 2., 30 or 60 min respectively. X_ray diffraction of the samples indicated the Cr 3C 2.decomposed partially after high pressure and temperature treatment, and Cr 7C 3, Cr and diamond formed respectively. There was not any trace of graphite in the samples. The result suggested that the separated carbon atoms could form diamond directly without conversion process of graphite into diamond. The observation of SEI, WDX and EDX also showed that diamond crystals were synthesized in the system, which have perfect surfaces and shapes, with the average grain size of about 40 μm. The properties of the crystals are being investigated.

关键词： chromium_carbide high pressure synthesis diamond.