检索结果-南通市图书馆

Effects of Carbon Content on Mechanical Properties of Inconel 718 Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2015年第1期22卷 78-83页

作者： Wen-jie ZHENG Xian-ping WEI Zhi-gang song qi-long YONG Han FENG qing-cheng XIE Central Iron and Steel Research Institute Materials Research Center Dong Fang Steam Turbine Works No.704 Institute of China Shipbuilding Industry Corporation

For improving the service performance of Inconel 718 alloy, especially used as a corrosion-resistant alloy for special environment, the microstructure and mechanical property of different carbon-containing Inconel 718 alloys were investigated by the Thermo-Calc software and experiments. The experimental results indicated that the mor- phology, distribution and types of carbides mainly existing in the form of MC＇were hardly influenced by solution treatment at 1050 ℃ for 1 h. The precipitation amount and particle size of carbides decreased with the decrease of carbon content, which was the main reason resulting in the increase of ductility and toughness. In addition, moving dislocation could be restrained by the precipitation of carbides. Therefore, the strength could benefit from the precip- itation strengthening of carbides when the precipitation of γ′/γ″ phase was not influenced by the precipitation of carbides.

关键词： Inconel 718 alloy microstructure carbide mechanical property precipitation strengthening

Strain-induced Precipitation Behavior ofδPhase in Inconel 718 Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2014年第3期21卷 375-381页

作者： Xian-ping WEI Wen-jie ZHENG Zhi-gang song Ting LEI qi-long YONG qing-cheng XIE Faculty of Metallurgical and Energy Engineering Kunming University of Science and Technology Central Iron and Steel Research Institute No.704 Institute of China Shipbuilding Industry Corporation

To study the precipitation dynamics of 3 phase in Inconel 718 alloy, two-stage interrupted compression method was used in the region of cold deformation temperatures and the temperatures range from 875 to 975 ℃. The precipitation-time-temperature （PTT） curve of 3 phase was obtained by analyzing the softening kinetics curves. For verifying the type of the precipitates and confirming the validity of the test, the transmission electron microscopy （TEM）, scanning transmission electron microscopy （STEM） and energy dispersion spectrum （EDS） were em- ployed. Experimental results indicated that the PTT curve for 3 precipitation exhibited a typical ＂C＂ shape and the nose points of start and finish precipitation were about 5 s at 920 ℃ and 2 815 s at 940 ℃, respectively. In addition, the nucleation of δ was heterogeneous. The nucleation sites varied with temperatures, including dislocation, grain boundary and stacking fault within γ″ phase. And 3 particles grew quickly at higher temperature with lower density. Moreover, the driving force of nucleation was mainly including chemical free energy, interracial energy and disloca- tion distorted energy. And the dislocation distorted energy could decide the density of nucleation in the strain-induced process.

关键词： Inconel 718 alloy strain-induced precipitation cold deformation nucleation site

A linear complementarity model for multibody systems with frictional unilateral and bilateral constraints

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2011年第4期27卷 587-592页

作者： Hai-ping Gao qi Wang Shi-Min Wang li Fu Department of dynamics and control Beihang University 100191 Beijing China

The Lagrange-I equations and measure differential equations for multibody systems with unilateral and bilateral constraints are constructed. For bilateral constraints, frictional forces and their impulses contain the products of the filled-in relay function induced by Coulomb friction and the absolute values of normal constraint reactions. With the time-stepping impulse-velocity scheme, the measure differential equations are discretized. The equations of horizontal linear complementarity problems （HLCPs）, which are used to compute the impulses, are constructed by decomposing the absolute function and the filled-in relay function. These HLCP equations degenerate into equations of LCPs for frictional unilateral constraints, or HLCPs for frictional bilateral constraints. Finally, a numerical simulation for multibody systems with both unilateral and bilateral constraints is presented.

关键词： Coulomb friction Bilateral constraint Unilat-eral constraint - Horizontal linear complementarity problem(HLCP) Time-stepping impulse-velocity algorithm

Mechanistic Aspects of Monomer, Polymer Formation, and Synthesis of PQ-Alt-Dialkyl-fluorene Conjugated Copolymer

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2008年第1期24卷 110-115页

作者： Muddasir Hanif LU ping ZHENG Yan li Mao XIE Zeng-qi MA Yu-guang li Di li Jing-hong key Lab for Supramolecular Structure and Materials of Ministry of Education Jilin University Changchun 130012 P. R. China Department of Chemistry Tsinghua University Beijing 100084 P. R. China

Suzuki coupling reaction is widely used in the construction of conjugated polymers; however, there is still no report describing the mechanism and coupling of 9,10-phenanthrenequinone（PQ） building blocks via Suzuki reaction because PQ is sensitive to bases and light. Herein is reported the efficient Suzuki coupling of PQ with 9,10-dialkylfluorene with Na2CO3 as basic species and high molecular weight PQ-Alt-Dialkyl-Fluorene conjugated copolymer obtained in an yield of 42%. Based on the characterization data and well-accepted literature, we proposed a step-by-step mechanistic explanation for the formation of the PQ containing alternating conjugated copolymer.

关键词： 9,10-Phenanthrenequinone Rearrangement Mechanism Conjugated polymer

Study on Compressive Properties of Z-pinned Laminates in RTD and Hygrothermal Environment

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2012年第1期25卷 64-70页

作者： li Chenghu YAN Ying WANG ping qi Desheng WEN Yonghai School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China China Electric Power Research Institute Beijing 100192China AVIC Harbin Aircraft Industry Group Co.Ltd. Harbin 150066China

Compressive tests of [0]t2 and [90]t2 unidirectional laminates and [45/0/-45/90] 2s quasi-isotropic laminates are accomplished in both room-temperature and dry （RTD） and hygrothermal environment. And simulation studies on the compressive strength of Z-pinned laminates of [0112 and [45/0/-45/90] 2s are conducted by using finite element analysis （FEA）. A microstructural unit cell for FEA is created to simulate a representative laminates unit with one pin. Within the unit cell, the first directions of the elements＇ material coordinate systems are changed to simulate the fibres＇ deflecting around the pin. The hygrothermal effect is simulated by the material properties＇ adjustments which are determined by the compressive tests of non-pined laminates. The experimental results indicate that the percentage of reduction in the compressive modulus of Z-pinned laminates caused by Z-pin becomes smaller with the percentage of 0° fibres decreasing in the laminates; the compressive strength of quasi-isotropic laminates reduces and the percentage of the reduction in the compressive strength declines with Z-pin volume content increasing, and the moisture absorption ratio of the Z-pinned specimens is greater than that of the non-pinned specimens, because the cracks around Z-pin increase the moisture absorption. In addition, the simulations show that the deflection of fibres around Z-pin is the main factor for the reduction in the compressive strength of Z-pinned unidirectional laminates, the dilution of fibre volume content caused by resin-rich pocket is the principal factor for the decline in the compressive strength of Z-pinned quasi-istropic laminates, and the compressive strength of Z-pinned specimens in hygrothermal environment reduces as the result of superimposition of some factors, including the changes in material properties caused by hygrothermal environment, the deflection of fibres and the resin-rich pocket caused by Z-pin.

关键词： Z-pin laminates hygrothermal environment simulation study strength

Crystallization of RE_(2)(OH)_(2)CO_(3)SO_(4)·nH_(2)O as a new family of layered hydroxides(RE=Gd-Lu lanthanides and Y),derivation of RE_(2)O_(2)SO_(4),photoluminescence and optical thermometry

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第8期42卷 1496-1506,I0003页

作者： Fan li Zhenqi song Zhiyuan Pan Sihan Feng qi Zhu Ji-guang li key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang110819China Research Center for Functional Materials National Institute for Materials ScienceTSsukuboaIbaraki3050044Japan

Layered rare-earth hydroxides(LREHs) draw wide research interest because of their peculiar crystal structure,rich interlayer chemistry and abundant functionality of the RE element,but are limited to the two categories of RE_(2)(OH)_(5)A·nH_(2)O(A:typical of Cl^(-)or NO_(3)^(-)) and RE_(2)(OH)_(4)SO_(4)·nH_(2)*** the other hand,rare-earth oxysulfates(RE_(2)O_(2)SO_(4)) have attracted attention due to their properties of large-capacity oxygen storage,low-temperature magnetism and luminescence,but their preparation procedure mostly involves toxic SO_(x) gases and/or complicated *** this work,RE_(2)(OH)_(2)CO_(3)SO_(4)·nH_(2)O as a new family of LREHs(RE=Gd-Lu lanthanides and Y) were produced via hydrothermal reaction,from which phase-pure RE_(2)O_(2)SO_(4) was derived via subsequent annealing at 800℃ in air without the involvement of SO_(x),The compounds were thoroughly characterized to reveal the intrinsic influence of lanthanide contraction(RE^(3+) radius) on crystal structure,thermal behavior(dehydroxylation/decarbonation/desulfurization),vibrational property and crystallite *** analyzing the photoluminescence of Eu^(3+) and Sm^(3+)in the Gd_(2)O_(2)SO_(4) typical host it is found that the 617 nm(Eu^(3+),λ_(ex)=275 nm) and 608 nm(Sm^(3+),λ_(ex)=407 nm) main emissions can retain as high as ^(7)9.6% and 85.5%of their room-temperature intensities at 423 K,with activation energies of ~0.19 and 0.21 eV for thermal quenching,*** also indicates that both the phosphors have the potential for optical temperature sensing via the fluorescence intensity ratio(FIR) technology,whose maximum relative sensitivity reaches -2.70%/K for Eu^(3+)and 1.73%/K for Sm^(3+) at 298 K.

关键词： Layered hydroxide RE_(2)O_(2)SO_(4) Luminescence Optical temperature sensing Rare earths

Xanthophyll Cycle and Inactivation of Photosystem Ⅱ Reaction Centers Alleviating Reducing Pressure to Photosystem Ⅰ in Morning Glory Leaves under Short-term High Irradiance

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2007年第7期49卷 1047-1053页

作者： Xin-Guo li Jian-Yong li Jin-ping Zhao ping-li Xu qi-Wei He. High-Tech Research Center Shandong Academy of Agricultural Sciences Ji' nan 250100 China Ji' nan Entry-exit Inspection Quarantine Bureau of the People's Republic of China Ji' nan 250100 China Vegetable Institute Shandong Academy of Agricultural Sciences Ji' nan 250100 China

Under 30-min high irradiance （1500μmol m^-2 s^-1）, the roles of the xanthophyll cycle and D1 protein turnover were investigated through chlorophyll fluorescence parameters in morning glory （Ipomoea setosa） leaves, which were dipped into water, dithiothreitol （DTT） and lincomycin （LM）, respectively. During the stress, both the xanthophyll cycle and D1 protein turnover could protect PSI from photoinhibition. In DTT leaves, non-photochemical quenching （NPQ） was inhibited greatly and the oxidation level of P700 （P700^＋） was the lowest one. However, the maximal photochemical efficiency of PSII （Fv/Fm） in DTT leaves was higher than that of LM leaves and was lower than that of control leaves. These results suggested that PSI was more sensitive to the loss of the xanthophyll cycle than PSII under high irradiance. In LM leaves, NPQ was partly inhibited, Fv/Fm was the lowest one among three treatments under high irradiance and P700^＋ was at a similar level as that of control leaves. These results implied that inactivation of PSII reaction centers could protect PSI from further photoinhibition. Additionally, the lowest of the number of active reaction centers to one inactive reaction center for a PSII cross-section （RC/CSo）, maximal trapping rate in a PSll cross-section （TRo/CSo）, electron transport in a PSll cross-section （ETo/CSo） and the highest of 1-qP in LM leaves further indicated that severe photoinhibition of PSII in LM leaves was mainly induced by inactivation of PSII reaction centers, which limited electrons transporting to PSh However, relative to the LM leaves the higher level of RC/CSo, TRo/CSo, Fv/Fm and the lower level of 1-qP in DTT leaves indicated that PSI photoinhibition was mainly induced by the electron accumulation at the PSI acceptor side, which induced the decrease of P700^＋ under high irradiance.

关键词： D1 protein high irradiance morning glory photoinhibition xanthophyll cycle.

Nanocavity-Mediated Fast Magnetic Vortex Core In-Situ Switching by Local Magnetic Field

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 Physics Letters 2021年第12期38卷 76-79页

作者： Xiao-ping Ma Hongguo Yang Changfeng li Cheng song Hong-guang Piao Hubei Engineering Research Center of Weak Magnetic-Field Detection College of ScienceChina Three Gorges UniversityYichang 443002China key Laboratory of Advanced Materials(MOE) School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Fast in situ switching of magnetic vortex core in a ferromagnetic nanodisk assisted by a nanocavity,with diameter comparable to the dimension of a vortex core,is systematically investigated by changing the strength as well as the diameter of the effective circular region of the applied magnetic *** applying a local magnetic field within a small area at the nanodisk center,fast switching time of about 35 ps is achieved with relatively low field strength(70 mT)which is beneficial for fast data reading and *** reason for this phenomenon is that the magnetic spins around the nanocavity is aligned along the cavity wall due to the shape anisotropy when the perpendicular field is applied,which deepens the dip around the vortex core,and thus facilitates the vortex core switching.

关键词： strength cavity vortex

Flexible micro-supercapacitors fabricated from MnO2 nanosheet/graphene composites with black phosphorus additive

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2022年第1期32卷 10-19页

作者： Baocheng liu Zongsheng Cao Zhengchun Yang Wen qi jie He Peng Pan Huayi li ping Zhang School of Electrical and Electronic Engineering Advanced Materials and Printed Electronics Center Tianjin Key Laboratory of Film Electronic & Communication DevicesTianjin University of Technology CISRI HIPEX Technology Co LTD China Iron & Steel Research Institute Group School of Electrical and Information Engineering Tianjin University

Supercapacitors are widely used for powering flexible/wearable electronics owing to their excellent charge storage capabilities. In this study, MnO2nanosheets were grown on the surface of graphene using a simple water bath method to prepare graphene/MnO2composites for fabricating supercapacitors. In addition, two-dimensional black phosphorus was introduced as an additive into the electronic ink based on the as-prepared graphene/MnO2composites. The characterization and electrochemical analyses results showed that adding black phosphorus considerably improved the capacitive performance of the material, yielding a high specific capacitance of241.5 Fg-1at 0.1 Ag-1and an impressive rate capability improvement from 52.5% to 80.3%. Then the microsupercapacitor having an area-specific capacitance of 20.15 mF cm-2at a scanning rate of 2 m V s-1was utilized to demonstrate the practical applicability of this material. To further evaluate the practical applicability of this micro-supercapacitor, the micro-supercapacitor was integrated with a flexible thin-film pressure sensor on paper and cloth through screen printing.

关键词： Manganese dioxide nanosheets Graphene Black phosphorus Micro-supercapacitor