期刊文献+
共找到946篇文章
< 1 2 48 >
每页显示 20 50 100
STABILIZATION OF MARTENSITE IN Cu-Zn-Al ALLOY AND ITS REVERSE SHAPE MEMORY EFFECT 被引量:5
1
作者 Cheng Yan and Wang Mingpu Department of Materials Science and Engineering, Central South University of Technology, Changsha 410083, P. R. China 《中国有色金属学会会刊:英文版》 CSCD 1998年第4期121-125,共5页
INTRODUCTIONThestabilizationofmartensitereferstothephenomenonthatthereversetransformationstartandfinishtempe... INTRODUCTIONThestabilizationofmartensitereferstothephenomenonthatthereversetransformationstartandfinishtemperatures(AsandAf)i... 展开更多
关键词 SMA STABILIZATION of MARTENSITE reverse SHAPE MEMORY effect
下载PDF
Giant reversible barocaloric effects with high thermal cycle stability in epoxybonded(MnCoGe)_(0.96)(CuCoSn)_(0.04) composite
2
作者 Yafei Kuang Kun Tao +7 位作者 Bo Yang Peng Tong Yan Zhang Zhigang Sun Kewei Zhang Dunhui Wang Jifan Hu Liang Zuo 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第11期2528-2534,共7页
Hexagonal MnMX-based(M=Co or Ni,X=Si or Ge)alloys exhibit giant reversible barocaloric effects.However,giant volume expansion would result in the as-cast MnMX ingots fragmenting into powders,and inevitably bring the d... Hexagonal MnMX-based(M=Co or Ni,X=Si or Ge)alloys exhibit giant reversible barocaloric effects.However,giant volume expansion would result in the as-cast MnMX ingots fragmenting into powders,and inevitably bring the deterioration of mechanical properties and formability.Grain fragmentation can bring degradation of structural transformation entropy change during cyclic application and removal of pressure.In this paper,giant reversible barocaloric effects with high thermal cycle stability can be achieved in the epoxy bonded(MnCoGe)0.96(CuCoSn)0.04 composite.Giant reversible isothermal entropy change of 43.0 J·kg^(−1)·K^(−1) and adiabatic temperature change from barocaloric effects(ΔT_(BCE))of 15.6 K can be obtained within a wide temperature span of 30 K at 360 MPa,which is mainly attributed to the integration of the change in the transition temperature driven by pressure of−101 K·GPa^(−1) and suitable thermal hysteresis of 11.1 K.Further,the variation of reversibleΔ_(TBCE) against the applied hydrostatic pressure reaches up to 43 K·GPa^(−1),which is at the highest level among the other reported giant barocaloric compounds.More importantly,after 60 thermal cycles,the composite does not break and the calorimetric curves coincide well,demonstrating good thermal cycle stability. 展开更多
关键词 barocaloric effects cycle stability reversible isothermal entropy change reversible adiabatic temperature change MnCoGe alloys
下载PDF
Effects of Predeformation on the Reverse Martensitic Transformation of TiNi Shape Memory Alloy 被引量:14
3
作者 Yanjun ZHENG Lishan CUI +1 位作者 Fan ZHANG Dazhi YANG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2000年第6期611-614,共4页
DSC was used to study the effects of predeformation on the reverse martensitic transformation of near-equiatomic TiNi alloy. Both the start temperature As and the finish temperature Af of the reverse transformation in... DSC was used to study the effects of predeformation on the reverse martensitic transformation of near-equiatomic TiNi alloy. Both the start temperature As and the finish temperature Af of the reverse transformation increased with increasing degree of predeformation, but the algebraic difference between As and Af decreased with increasing predeformation until it reached a minimum value, then remained unchanged with further deformation. Transformation heat also increased with increasing predeformation until it reached a maximum value, then decreased with further predeformation. All the phenomena above were considered to be closely related with the release of elastic strain energy during predeformation. 展开更多
关键词 TINI effects of Predeformation on the reverse Martensitic Transformation of TiNi Shape Memory Alloy
下载PDF
MICROSTRUCTURE AND REVERSE SHAPE MEMORY EFFECT IN A Cu-Zn-Al ALLOY 被引量:1
4
作者 DONG Jianxin CHEN Fumin CHEN Jinming LIU Wenxi Tianjin University,Tianjin,China At pressent he works in Department of materials Science and Technology,University of Science and Technology,Beijing. 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1991年第3期221-224,共4页
The bainite structure in a Cu-Zn-A1 alloy related to the reverse shape memory effect has been observed by means of TEM.The reverse memory effect may be improved by up to one order of magnitude under applied constraint... The bainite structure in a Cu-Zn-A1 alloy related to the reverse shape memory effect has been observed by means of TEM.The reverse memory effect may be improved by up to one order of magnitude under applied constraint stress.The widespread propagation of bainite was confirmed to be the diffusion controlled shear process by the parabolic configuration of side interface of bainite plate and the twisting of intersected bainite plates. 展开更多
关键词 Cu-Zn-Al memory alloy reverse shape memory effect bainitic transformation
下载PDF
THE FAILURE MECHANISM OF REVERSE SHAPE MEMORYEFFECT IN A Cu-BASE ALLOY
5
作者 C.M Li G.X. Dong +1 位作者 S.T- Dai and D. Y Chen (Tsinghua University Beijing 100084, China)J Yin and D.X. Hu (Shanghai No.5 Steel Works, Shanghai 200940, China) 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1997年第3期203-205,共3页
The interior structural evolution accompanying reverse shape memory effect (RSMEin a Cu-Zn-Al alloy was studied by means of transmission electron microscopy. It was found that RSME is closely related to bainitic trans... The interior structural evolution accompanying reverse shape memory effect (RSMEin a Cu-Zn-Al alloy was studied by means of transmission electron microscopy. It was found that RSME is closely related to bainitic transformation in this alloy during the isothermal reaction at moderate temperatures. At a given temperature and a certain external constraint stress, the shape memory effect depends mainly on the aging time.During the early stage, the shape memory effect enhances with the increase of reactiotn time. Then it will decrease gradually apon further aging. If the alloy is overaged, the stacking faults of bainite will disappear gradually by the motion of partial dislocations through which long range diffusion of solute atoms takes place, giving rise to the deterioration of RSME. When all the bainite transforms to α phase, RSME will lose completely. 展开更多
关键词 reverse shape memory effect Cu-base alloy stacking fault BAINITE
下载PDF
Experimental and Modeling Investigation of Shallow Water Table Fluctuations in Relation to Reverse Wieringermeer Effect
6
作者 Ibrahimi Mohamed Khaled Miyazaki Tsuyoshi +2 位作者 Nishikawa Kohei Nishimura Taku Imoto Hiromi 《Open Journal of Soil Science》 2011年第2期17-24,共8页
Soil column experiments and modeling investigations were performed to study the behavior of shallow water table in response to various recharge events. Hence, shallow water table fluctuations inside sandy (Toyoura san... Soil column experiments and modeling investigations were performed to study the behavior of shallow water table in response to various recharge events. Hence, shallow water table fluctuations inside sandy (Toyoura sand) and clayey (Chiba light clay) soil columns in response to surface and sub-surface recharge events were investigated under laboratory conditions. Experimental results showed that small application of water could raise the shallow water table level more than 100 times in depth in the case of Toyoura sand and more than 50 times in the case of Chiba LiC, reflecting a reverse Wieringermeer effect (RWE) response type of groundwater. This rise was associated with a prompt change of pressure head values which exhibited instantaneous fluctuations of centimeters due to the addition of millimeters of water. The recharge volumes leading to such disproportionate water table rise were successfully estimated using a simple analytical model based on the moisture retention curve of the soil and considering the hysteresis effect on soil water dynamics within the capillary fringe zone. 展开更多
关键词 Groundwater FLUCTUATION SHALLOW Water TABLE reverse Wieringermeer effect CAPILLARY FRINGE
下载PDF
High-performance vertical GaN field-effect transistor with an integrated self-adapted channel diode for reverse conduction
7
作者 邓思宇 廖德尊 +3 位作者 魏杰 张成 孙涛 罗小蓉 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第7期570-576,共7页
A vertical GaN field-effect transistor with an integrated self-adapted channel diode(CD-FET)is proposed to improve the reverse conduction performance.It features a channel diode(CD)formed between a trench source on th... A vertical GaN field-effect transistor with an integrated self-adapted channel diode(CD-FET)is proposed to improve the reverse conduction performance.It features a channel diode(CD)formed between a trench source on the insulator and a P-type barrier layer(PBL),together with a P-shield layer under the trench gate.At forward conduction,the CD is pinched off due to depletion effects caused by both the PBL and the metal-insulator-semiconductor structure from the trench source,without influencing the on-state characteristic of the CD-FET.At reverse conduction,the depletion region narrows and thus the CD turns on to achieve a very low turn-on voltage(V_(F)),preventing the inherent body diode from turning on.Meanwhile,the PBL and P-shield layer can modulate the electric field distribution to improve the off-state breakdown voltage(BV).Moreover,the P-shield not only shields the gate from a high electric field but also transforms part of C_(GD)to CGS so as to significantly reduce the gate charge(Q_(GD)),leading to a low switching loss(E_(switch)).Consequently,the proposed CD-FET achieves a low V_(F)of 1.65 V and a high BV of 1446 V,and V_(F),Q_(GD)and E_(switch)of the CD-FET are decreased by 49%,55%and 80%,respectively,compared with those of a conventional metal-oxide-semiconductor field-effect transistor(MOSFET). 展开更多
关键词 GaN field effect transistor reverse conduction integrated diode turn-on voltage
下载PDF
The Effects of Reverse Transcriptase Inhibitor on Radiosensitization of Human Malignant Glioma Cells
8
作者 Jing DAI Fu-Xiang ZHOU Cong-Hua XIE Zhi-Guo LUO Yun-Feng ZHOU~Δ(Department of Radio-Chematherapy of Zhongnan Hospital and Cancer Research Center, Wuhan University, Wuhan 430071, China) 《生物医学工程学杂志》 EI CAS CSCD 北大核心 2005年第S1期121-122,共2页
关键词 The effects of reverse Transcriptase Inhibitor on Radiosensitization of Human Malignant Glioma Cells DSB AZT
下载PDF
Twice reverse shape memory effect in CuZnAl shape memory alloy
9
作者 李周 汪明朴 +1 位作者 徐根应 郭明星 《中国有色金属学会会刊:英文版》 CSCD 2004年第4期697-701,共5页
The variations of the shape memory effects in the Cu-13Zn-15Al(mole fraction,%) alloy upon successive heating (the rate of heating is 5 ℃/min) have been st udied by means of ρ—T curve,shape memory effect measuremen... The variations of the shape memory effects in the Cu-13Zn-15Al(mole fraction,%) alloy upon successive heating (the rate of heating is 5 ℃/min) have been st udied by means of ρ—T curve,shape memory effect measurement,optical met allographical observation and X-ray diffraction. The first abnormal reverse sha pe memory effect occurs when the tested alloy is heated to the temperature below 320 ℃;when it is heated to the temperature between 320 ℃ and 450 ℃,the forward shape memory effect occurs;in the two stages,the shape of the sample r emains the same as that in the furnace when it is taken out from the furnace and air-cooled;when the tested alloy is heated to the temperature above 450 ℃,the shape of the sample remains unchanged during heating,but the second reverse shape memory effect occurs after it is air-quenched. 展开更多
关键词 形状记忆合金 Cu-13Zn-15Al 形状记忆效应 马氏体 XRD ρ-T曲线
下载PDF
Effects of Temperature on Reverse Short Channel Effect in Pocket Implanted Sub-lO0 nm n-MOSFET
10
作者 Muhibul Haque Bhuyan Quazi Deen Mohd Khosru 《材料科学与工程(中英文版)》 2010年第7期18-23,共6页
关键词 MOSFET 通道效应 低温度 金属氧化物半导体场效应晶体管 纳米 反向 电压模型 阈值电压
下载PDF
Substrate matters:The influences of substrate layers on the performances of thin-film composite reverse osmosis membranes 被引量:5
11
作者 Jie Li,Mingjie Wei YongWang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第11期1676-1684,共9页
Thin-film composite(TFC) reverse osmosis(RO) membranes are playing the dominating role in desalination.Tremendous efforts have been put in the studies on the polyamide selective layers. However, the effect of the subs... Thin-film composite(TFC) reverse osmosis(RO) membranes are playing the dominating role in desalination.Tremendous efforts have been put in the studies on the polyamide selective layers. However, the effect of the substrate layers is far less concerned. In this review, we summarize the works that consider the impacts of the substrates, including pore sizes, surface hydrophilicity, on the processes of interfacial polymerization and consequently on the morphologies of the active layers and on final RO performances of the composite membranes. All the works indicate that the pore sizes and surface hydrophilicity of the substrate evidently influence the RO performances of the composite membranes. Unfortunately, we find that the observations and understandings on the substrate effect are frequently varied from case to case because of the lack of substrates with uniform pores and surface chemistries. We suggest using track-etched membranes or anodized alumina membranes having relatively uniform pores and functionalizable pore walls as model substrates to elucidate the substrate effect.Moreover, we argue that homoporous membranes derived from block copolymers have the potential to be used as substrates for the large-scale production of high-performances TFC RO membranes. 展开更多
关键词 reverse osmosis Thin-film composite Interfacial polymerization Homoporous membranes Substrate effect
下载PDF
Multiple reversals of vortex ratchet effects in a superconducting strip with inclined dynamic pinning landscape 被引量:1
12
作者 An He Cun Xue 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第12期448-454,共7页
Using time-dependent Ginzburg-Landau formalism,we investigate the multiple reversals of ratchet effects in an unpatterned superconducting strip by the tilted dynamic pinning potential.In the case of collinear sliding ... Using time-dependent Ginzburg-Landau formalism,we investigate the multiple reversals of ratchet effects in an unpatterned superconducting strip by the tilted dynamic pinning potential.In the case of collinear sliding potential and Lorentz force,vortices are always confined in the channels induced by sliding potential.However,due to the inclination angle of sliding pinning potential with respect to the Lorentz force,vortices could be driven out of the channels,and unexpected results with multiple reversals of vortex rectifications are observed.The mechanism of multiple reversals of vortex rectifications is explored by analyzing different vortex motion scenarios with increasing ac current amplitudes.The multiple reversals of transverse and longitudinal ratchet effects can be highly controlled by ac amplitude and dynamic pinning velocity.What's more,at certain large current the ratchet effect reaches strongest within a wide range of pinning sliding velocity. 展开更多
关键词 multiple reversal ratchet effect dynamic pinning potential Lorentz force
下载PDF
Study of magnetization reversal and anisotropy of single crystalline ultrathin Fe/MgO (001) film by magneto-optic Kerr effect
13
作者 张苗玲 叶军 +5 位作者 刘锐 米菽 谢勇 刘郝亮 Chris Van Haesendonck 陈子瑜 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第4期370-375,共6页
The magnetization reversal process of Fe/MgO (001) thin film is investigated by combining transverse and longi- tudinal hysteresis loops. Owing to the competition between domain wall pinning energy and weak uniaxial... The magnetization reversal process of Fe/MgO (001) thin film is investigated by combining transverse and longi- tudinal hysteresis loops. Owing to the competition between domain wall pinning energy and weak uniaxial magnetic anisotropy, the typical magnetization reversal process of Fe ultrathin film can take place via either an "l-jump" process near the easy axis, or a "2-jump" process near the hard axis, depending on the applied field orientation. Besides, the hysteresis loop presents strong asymmetry resulting from the variation of the detected light intensity due to the quadratic magneto-optic effect. Furthermore, we modify the detectable light intensity formula and simulate the hysteresis loops of the Kerr signal. The results show that they are in good agreement with the experimental data. 展开更多
关键词 magnetization reversal process magneto-optic Kerr effect magnetic anisotropy
下载PDF
On the origin of the anomalous sign reversal in the Hall effect in Nb thin films
14
作者 Dan Zhou HanSong Zeng +4 位作者 Rujun Tang Zhihong Hang Zhiwei Hu Zixi Pei Xinsheng Ling 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第3期527-532,共6页
We re-visit the anomalous sign reversal problem in the Hall effect of the sputtered Nb thin films. We find that the anomalous sign reversal in the Hall effect is extremely sensitive to a small tilting of the magnetic ... We re-visit the anomalous sign reversal problem in the Hall effect of the sputtered Nb thin films. We find that the anomalous sign reversal in the Hall effect is extremely sensitive to a small tilting of the magnetic field and to the magnitude of the applied current. Large anomalous variations are also observed in the symmetric part of the transverse resistance R_(xy).We suggest that the surface current loops on superconducting grains at the edges of the superconducting thin films may be responsible for the Hall sign reversal and the accompanying anomalous effects in the symmetric part of R_(xy). 展开更多
关键词 anomalous sign reversal Hall effect edge supercurrents Aharonov–Bohm effect
下载PDF
Mode structure symmetry breaking of reversed shear Alfvén eigenmodes and its impact on the generation of parallel velocity asymmetries in energetic particle distribution
15
作者 Guo MENG Philipp LAUBER +1 位作者 Xin WANG Zhixin LU 《Plasma Science and Technology》 SCIE EI CAS CSCD 2022年第2期17-27,共11页
In this work,the gyrokinetic eigenvalue code LIGKA,the drift-kinetic/MHD hybrid code HMGC and the gyrokinetic full-f code TRIMEG-GKX are employed to study the mode structure details of reversed shear Alfvén eigen... In this work,the gyrokinetic eigenvalue code LIGKA,the drift-kinetic/MHD hybrid code HMGC and the gyrokinetic full-f code TRIMEG-GKX are employed to study the mode structure details of reversed shear Alfvén eigenmodes(RSAEs).Using the parameters from an ASDEXUpgrade plasma,a benchmark with the three different physical models for RSAE without and with energetic particles(EPs)is carried out.Reasonable agreement has been found for the mode frequency and the growth rate.Mode structure symmetry breaking(MSSB)is observed when EPs are included,due to the EPs’non-perturbative effects.It is found that the MSSB properties are featured by a finite radial wave phase velocity,and the linear mode structure can be well described by an analytical complex Gaussian expressionФ(s)=e^(-σ(s-s_(0))^(2))with complex parametersσand s_(0),where s is the normalized radial coordinate.The mode structure is distorted in opposite manners when the EP drive shifted from one side of qminto the other side,and specifically,a non-zero average radial wave number with opposite signs is generated.The initial EP density profiles and the corresponding mode structures have been used as the input of HAGIS code to study the EP transport.The parallel velocity of EPs is generated in opposite directions,due to different values of the average radial wave number,corresponding to different initial EP density profiles with EP drive shifted away from the qmin. 展开更多
关键词 reversed shear Alfvén eigenmode symmetry breaking energetic particles non-perturbative effects
下载PDF
Reverse Direction Micellar Electrokinetic Capillary Chromatography, Hydrostatic Flow Injection and Diffusional Injection Analysis: An Experimental Work
16
作者 Kiumars Ghowsi Hosein Ghowsi 《Journal of Chemistry and Chemical Engineering》 2014年第6期552-556,共5页
Separation was reported by Dunn, Hankins and Ghowsi for the case that ions incapillary electrophoresis move opposite to electroosmosis and ions move faster than flow finally they get separated and reach the detector. ... Separation was reported by Dunn, Hankins and Ghowsi for the case that ions incapillary electrophoresis move opposite to electroosmosis and ions move faster than flow finally they get separated and reach the detector. Similar mode for electrokinetic chromatography is reported for p-xylene and toluene separation, which is called reverse direction MECC (micellar electrokinetic capillary chromatography). The effect of injection time on separation in reverse direction micellar electrokinetic capillary chromatography is investigated. In this study, hydrostatic and diffusion injection were studied. 展开更多
关键词 reverse direction MECC P-XYLENE TOLUENE hydrostatic injection diffusion injection effective mobility.
下载PDF
A Modified Lattice Model of the Reversible Effect of Axial Strain on the Critical Current of Polycrystalline REBa2Cu3O7-δ Films
17
作者 苟晓凡 朱光 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第3期128-132,共5页
The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ (REBCO, RE: rare earth) films, in which the reversible effect is intrinsic in the range of strain ... The strain effect on the critical current is one of the most important properties for polycrystalline YBa2 Cu3O7-δ (REBCO, RE: rare earth) films, in which the reversible effect is intrinsic in the range of strain 0 and the irreversible strain εirr. By introducing the applied strain, a modified grain boundaries (GBs) in the REBCO film is developed. lattice model combining the strain and misorientation of A good agreement of the calculation on the lattice model with the experimental data shows that the lattice model is able to well describe the reversible effect of axial strain on the critical current of the REBCO film, and provides a good understanding of the mechanism of the reversible effect of the strain. Moreover, the effects of the crystallographic texture of the REBCO film and the residual strain εr on the variation of the critical current with the applied strain are extensively investigated. Furthermore by using the developed lattice model, the irreversible strain εirr of the REBCO film can be theoretically determined by comparing the calculation of the critical current-strain curve with the experimental data. 展开更多
关键词 REBCO A Modified Lattice Model of the reversible effect of Axial Strain on the Critical Current of Polycrystalline REBa2Cu3O FILMS Cu
下载PDF
培哚普利联合氨氯地平对原发性高血压伴左心室肥厚的逆转作用及对患者血浆N末端B型利钠肽原水平的影响
18
作者 张金春 王朝霞 李志华 《陕西医学杂志》 CAS 2025年第1期109-113,共5页
目的:探究培哚普利联合氨氯地平对原发性高血压伴左心室肥厚的逆转作用及对血浆N末端B型利钠肽原(NT-ProBNP)水平的影响。方法:选择原发性高血压伴左心室肥厚患者138例为研究对象,按随机数表法分为三组,均46例。对照组1予以氨氯地平治疗... 目的:探究培哚普利联合氨氯地平对原发性高血压伴左心室肥厚的逆转作用及对血浆N末端B型利钠肽原(NT-ProBNP)水平的影响。方法:选择原发性高血压伴左心室肥厚患者138例为研究对象,按随机数表法分为三组,均46例。对照组1予以氨氯地平治疗,对照组2予以培哚普利治疗,观察组采用培哚普利联合氨氯地平治疗。比较临床疗效、治疗前后血压情况、舒张末期左室内径(LVDd)、室间隔厚度(I与T)、左室后壁厚度(PWT)、左室重量指数(LVMI)及NT-ProBNP、同型半胱氨酸(Hcy)心钠肽(ANP)水平。结果:观察组总有效率为95.65%(44/46)高于对照组1[80.43%(37/46)]和对照组2[76.09%(35/46)](均P<0.05),对照组1和对照组2比较无统计学差异(P>0.05)。治疗前,三组收缩压、舒张压、I与T、PWT、LVMI及血清NT-ProBNP、Hcy、ANP水平比较,差异无统计学意义(均P>0.05),治疗后,观察组收缩压(127.87±13.66与136.46±15.73与135.00±15.98)、舒张压(81.07±5.58与83.98±7.16与85.57±7.22)、LVDd(46.48±2.24与48.37±3.62与48.30±3.57)、I与T(10.00±1.38与11.20±1.50与11.24±1.55)、PWT(10.52±1.35与12.24±1.40与12.37±1.39)、LVMI(124.57±10.80与145.13±10.27与144.93±10.34)、NT-ProBNP(64.53±15.63与75.23±18.46与78.15±18.54)、Hcy(8.93±2.68与15.48±4.66与14.88±4.62)、ANP(139.95±38.64与216.84±59.15与213.87±59.23)水平均较对照组1和对照组2下降(均P<0.05),对照组1和对照组2比较无统计学差异(P>0.05)。结论:培哚普利联合氨氯地平对原发性高血压伴左心室肥厚治疗效果较好,可有效降低血压、改善左室相关指标,并降低NT-Pro BNP水平。 展开更多
关键词 培哚普利 氨氯地平 原发性高血压伴左心室肥厚 血浆N末端B型利钠肽原水平 逆转作用
下载PDF
炎症、代谢物与骨质疏松症
19
作者 吕浩 张舸 +5 位作者 胡芷苜 王岩 楚庆松 周瑶 江渟 王久香 《中国组织工程研究》 CAS 北大核心 2025年第17期3697-3704,共8页
背景:多项研究表明炎症、代谢物与骨质疏松症之间存在密切关系,但炎症相关蛋白与骨质疏松症之间是否存在遗传因果效应以及代谢物是否在其中发挥中介效应尚不清楚。目的:采用孟德尔随机化方法研究了炎症相关蛋白和骨质疏松症的因果关系... 背景:多项研究表明炎症、代谢物与骨质疏松症之间存在密切关系,但炎症相关蛋白与骨质疏松症之间是否存在遗传因果效应以及代谢物是否在其中发挥中介效应尚不清楚。目的:采用孟德尔随机化方法研究了炎症相关蛋白和骨质疏松症的因果关系以及血浆代谢物在该关系中的中介作用。方法:利用全基因组关联研究(GWAS)的汇总数据,骨质疏松症数据来Fengenn数据库,炎症相关蛋白和血浆代谢物的数据来自己发表的研究。评估暴露与结局之间的关联性主要是反方差加权方法,通过双向孟德尔随机化分析探索炎症相关蛋白与骨质疏松症之间的因果关系,并通过两步孟德尔随机化分析发现潜在的发挥中介作用的血浆代谢物。随后进行敏感性分析以进一步验证结果的稳健性。采用Cochran’s Q检验评估研究结果的异质性。通过MR-Egger截距法和MR-PRESSO法进行水平多效性评估。结果与结论:(1)通过初步双向孟德尔随机化分析,鉴定出5种与骨质疏松症有正向因果关系且没有反向因果关系的炎症相关蛋白;其中神经鞘胚素(OR=0.895,95%CI:0.819-0.979,P=0.015)与骨质疏松症呈负相关,而趋化因子(C-X-C基序)配体1(OR=1.100,95%CI:1.002-1.209,P=0.046)。趋化因子(C-X-C基序)配体11(OR=1.150,95%CI:1.043-1.268,P=0.005)、白细胞介素17 C(OR=1.087,95%CI:1.004-1.176,P=0.040)、肿瘤坏死因子样凋亡微弱诱导因子(OR=1.108,95%CI:1.002-1.226,P=0.046)与骨质疏松症呈正相关;敏感性分析显示,这些因果效应都没有异质性和多效性。(2)文章还进行了两步孟德尔随机化分析发现潜在的中介血浆代谢物:1-棕榈酰gpc(16∶0)增加了神经鞘胚素对骨质疏松症的负向作用,5α-雄甾烷-3α,17β-单硫酸二醇会增加趋化因子(C-X-C基序)配体1、趋化因子(C-X-C基序)配体11介导的骨质疏松症风险性;Α-酮戊二酸与琥珀酸比值会导致趋化因子(C-X-C基序)配体11、白细胞介素17 C介导的骨质疏松症风险性增加;亚精胺、脯氨酸与反式-4-羟脯氨酸比值导致趋化因子(C-X-C基序)配体11介导的骨质疏松症风险性增加;12,13-二羟基十八碳烯酸会导致白细胞介素17 C介导的骨质疏松症风险性增加;胡椒碱代谢物C_(16)H_(19)NO_(3)(3)的硫酸盐水平、腺苷3′,5′-环单磷酸腺苷会导致肿瘤坏死因子样凋亡微弱诱导因子介导的骨质疏松症风险性增加。(3)上述数据证实,部分炎症相关蛋白可以影响骨质疏松症的风险,这种作用是正向和负向的,并且其中一部分作用由血浆代谢物介导,这为未来探究骨质疏松症的发生发展机制提供了新的认知。 展开更多
关键词 骨质疏松症 炎症相关蛋白 血浆代谢物 免疫反应 孟德尔随机化 因果关系 反向因果 双向分析 中介效应 全基因组关联研究
下载PDF
The Maximum Effective Moment Criterion (MEMC) and Its Implications in Structural Geology 被引量:15
20
作者 ZHENG Yadong WANG Tao WANG Xinshe 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2006年第1期70-78,共9页
The MohroCoulomb criterion has been widely used to explain formation of fractures. However, it fails to explain large strain deformation that widely occurs in nature. There is presently a new theory, the MEMC, which i... The MohroCoulomb criterion has been widely used to explain formation of fractures. However, it fails to explain large strain deformation that widely occurs in nature. There is presently a new theory, the MEMC, which is mathematically expressed as Meff = ((σ1-σ3) L.sin 2α sin α)/2, where σ1-σ3 represents the yield strength of the related rock, L is a unit length and a is the angle between σ1 and deformation bands. This criterion demonstrates that the maximum value appears at angles of ±54.7° to σ1 and there is a slight difference in the moment in the range of 55°±10°. The range covers the whole observations available from nature and experiments. Its major implications include: (1) it can be used to determine the stress state when the related deformation features formed; (2) it provides a new approach to determine the Wk of the related ductile shear zone if only the ratio of the vorticity and strain rate remains fixed; (3) It can be used to explain (a) the obtuse angle in the contraction direction of conjugate kink-bands and extensional crenulation cleavages, (b) formation of low-angle normal faults and high-angle reverse faults, (c) lozenge ductile shear zones in basement terranes, (d) some crocodile structures in seismic profiles and (e) detachment folds in foreland basins. 展开更多
关键词 maximum effective moment criterion crenulation cleavage low-angle normal fault high-angle reverse fault crocodile structure lozenge structure detachment fold
下载PDF
上一页 1 2 48 下一页 到第
使用帮助 返回顶部