最新色国产精品精品视频,中文字幕日韩一区二区不卡,亚洲有码转帖,夜夜躁日日躁狠狠久久av,中国凸偷窥xxxx自由视频

Abstract:介紹了磁致冷材料磁熱效應的表征方法，概述了國內外各溫度區(qū)間磁致冷材料的研究進展。在20K以下溫區(qū)，磁致冷材料研究主要集中在具有高導熱率、低點陣熱容和極低有序化溫度的石榴石，如Gd3Ga5O12(GGG)，Dy3Al5O12(DAG)，Gd3Ga5-xFexO12(GGIG)及Er基磁致冷材料；20K～77K溫度區(qū)間，磁致冷材料研究主要集中在重稀土金屬間化合物中，如(Dy1-xErx)Al2復合材料等；在室溫附近，具有大磁熱效應的磁致冷材料以稀土Gd，Gd5(SixGe1-x)4(0≤x≤0．5)和MnFeP1-xAsx(0．15≤x≤0．66)合金為代表，特別是Gd5Si2Ge2(Tc=274K)和MnFeP0.45As0.55(Tc=300K)合金，在磁場5T下具有巨磁熱效應，是Gd的2倍以上?？偨Y了各溫度區(qū)間磁致冷材料的選擇依據(jù)。重點評述了室溫磁致冷材料的最新研究成果，展望了室溫磁致冷材料的發(fā)展前景。

Abstract:Nodular corrosion a local corrosion occurring on the surface of zirconium alloys usually in boiling water reactors (BWR), directly affects service life of the zirconium cladding and threatens the safety of reactors. The occurrence, propagation morphology of nodules and other characteristics of nodular corrosion, are summarized. The commonly accepted models of nodular corrosion include the hydrogen accumulation model of KUWAE[ref] and nucleation & growth model of ZHOU[ref]. Main driving factors include surface condition, heat treatment, alloying composition, presence of second phase particles and irradiation. Processes to suppress nodular corrosion are presented in the present paper, for instance: increasing the Fe+Cr content, decreasing the Sn content, decreasing the annealing time and temperature, improving the surface finish. But, the most effective means of improving nodular corrosion resistance is to use a new zirconium alloy containing niobium.

Abstract:The field variables model has recently emerged as a powerful approach for simulating microstructure evolution in materials. It describes the microstructure using a set of conserved and non-conserved field variables in the form of higher order differentials. It can predict and control complex microstructure evolution with these field variables by computer simulation. This paper reviews the fundamental principle of the field variables model and recent progress in the field of materials science and engineering.

Abstract:The effects on the electrochemical properties of AB5-type hydrogen storage alloys for Ni-MH batteries of adding elements to the A-side and the B-side are described. Advances in the worldwide development of low-Co or Co-free hydrogen storage alloys are reviewed. Considered are: component design, preparation technique, heat treatment and surface treatment. Prospects for the further development of low-cost hydrogen storage alloys and Ni-MH battery for electric vehicles (EVs) power are discussed.

Abstract:為了研究鈰,釔離子注入對純鋯耐蝕性的影響,純鋯樣品用MEVVA源以40 kV注入1×1016 ions/cm2至1×1017 ions/cm2劑量的釔和鈰,注入最高溫度約為150℃.用X光電子譜儀(XPS)分析注入表層元素的價態(tài);在1 mol/L硫酸溶液中3次極化測量來研究注入樣品的耐蝕性.對于釔離子注入,當注入劑量大于5×1016 ions/cm2時,注入樣品的耐蝕性顯著提高.用掠角X射線衍射(GAXRD)研究氧化膜中由于鈰離子注入發(fā)生的相轉移.三次極化測量表明注鈰樣品與空白樣品相比,耐蝕性下降許多.最后分別對注入釔和鈰樣品的腐蝕行為機理進行了探討.

Abstract:The modifying effects of a new type of Al-P master alloy on eutectic and hyper-eutectic Al-Si alloys were investigated. It is found that excellent modifying effect on these alloys can been obtained by adding the new type of Al-P master alloy. It is also found that the modifying efficiency of the Al-P master alloy can be improved by the addition of Al-8Ti-2C master alloy to the Al-Si melt. When the content of TiC particles (by Al-8Ti-2C master alloy) in the Al-24Si melt is 0.03%, the average and largest grain size of primary Si can be decreased to 41 m, 55 m from the original 47 m and 75 m. The modifying effect occurs after 50 minutes from adding the Al-P master alloy and the TiC particles, and remains steady with the increase in holding time. The average grain size of the primary Si can be decreased to 30 m from 50 m when the content of TiC particles in Al-12Si melt is 0.03%.

Abstract:通過時效硬化曲線測量及時效組織分析，研究了微量鈧對Al-15Ag合金時效行為和顯微組織的影響。在Al-15Ag合金中添加0．2％Sc(質量分數(shù)，下同)，可以增強合金在190℃和350℃時效的時效硬化效果，延長峰時效的到達時間。微量鈧的添加促使合金中y’相細小密集地析出，同時鈧的存在減少了y’相寬面上的位錯臺階數(shù)。含鈧Al-15Ag合金中y’相長大過程比較緩慢的微觀機理是微量鈧的添加影響了合金中y’相寬面上的臺階分布。

Abstract:Cu/Ni multilayers with various modulation wavelengths were deposited on a low carbon steel substrates by electrode positing method. Hardness measurements identified that the relationship between the yield strength (one-third of hardness) which increased with decrease of layer thickness for Cu/Ni multilayers and single layer thickness at sub-micron length scale--- could be described by the Hall-Petch (H-P) formula for dislocation pile-up. In the regime of few tens to a hundred nanometer of single layer thickness, the dislocation pileup-based H-P model breaks down. This can be explained in terms of the limiting dislocation size criterion proposed by Cheng et al.

Abstract:The effect of pressure annealing on the glass transition of bulk amorphous Zr55Cu30Al10Ni5 is studied by x-ray diffraction and differential scanning calorimeter (DSC). The apparent activation energy of the glass transition (Eg) was determined by the Kissinger method. The results show that the glass transition temperature and Eg of the specimens change nonlinearly with increase of the annealing pressure. The role of pressure on structural relaxation and the glass transition is discussed.

Abstract:The ternary alloy LaMg17Ni was prepared by mechanical alloying (MA) and its thermodynamic and kinetic properties were examined. This composite possesses high hydrogen storage capacity of 5.23 mass% at 553 K. Under 3.0 MPa hydrogen pressure, the alloy can absorb more than 90% of its full hydrogen capacity in less than 1 min at 423 K~573 K. X-ray diffraction and SEM were used to characterize the crystal structure, microstructures, and composition of the composite sample. It was found that the MA sample contained a mixture of La2Mg17, Mg2Ni, LaH2 and La particles. The kinetics of the sample was assisted the by catalytic action of Mg2Ni and La as well as the existence of the multiphase structure formed in the preparation process.

Abstract:Differential Scanning Calorimetric(DSC) techniques are used to study the precipitation behaviour of 7075 aluminum alloys and the influence of Li on the microstructure transformation of the7075-Li alloy during aging. The kinetic parameters for GP zones and h phase dissolution are calculated in 7075 and 7075+Li alloys. The results show that Li slightly affects the activation energy for GP zones dissolution, but markedly raises the activation energy for h phase dissolution.

Abstract:A pure quasicrystal with the composition Ti40Zr40Ni20 was obtained in bulk form by using conventional suction-casting. The quasi-lattice constant of the icosahedral phase (I-phase) is 0.523 nm. Differential scanning calorimetry (DSC) together with X-ray diffraction were used to study the temperature-induced phase transformation of the as-cast I-phase. Two endothermic reactions are identified in the DSC trace. The first endothermic reaction with an onset temperature of 964 K corresponds to eutectoid transformation from the I-phase to the C14-type Laves phase and -Zr(Ti) solid solution. The second one with an onset temperature of 1 107 K indicates the melting transformation of the eutectoid mixture.

Abstract:討論了TiMn0.85Cr0.35V0.3合金的活化性能和吸放氫性能?；罨阅艿慕Y果表明：合金表面氧化層的形成是影響合金活化的重要因素?？諝庵斜┞?0d的TiMn0.85Cr0.35V0.3合金粉，在P=1MPa，r=293K下，經(jīng)幾次活化循環(huán)后即可基本完全活化。PCT結果表明：退火處理可明顯改善該合金的儲氫性能。在1223K下退火6h的該合金在273K時的有效放氫量Ce、吸氫平臺壓力Pa和放氫平臺壓力Pd分別為1．55％(質量分數(shù))、0．141MPa和0．112MPa。符合作為燃料電池供氫源的應用要求。

Abstract:討論了環(huán)狀亞砜衍生物OTMSO萃鉑的性能和機理。隨著萃取劑濃度和水相中酸度的增加,萃取率上升。萃鉑反應是放熱反應。應用斜率法探討了COTMSO,CH+和CCl-對分配比的影響。亞砜的配位數(shù)是2,CH+對分配比的影響很大。用紅外光譜確定了配位原子。亞砜以酸性締合機理萃鉑,萃合物的組成為(H+·h1H2O·OTMSO)2PtCl62-,萃合物發(fā)生內配位轉變、亞砜進入萃合物內界,通過亞砜S=O中的硫與鉑配位。

Abstract:研究了含氫量為110μgg/和280μg/g的Ti-4Al-2V鈦合金在不同載荷比下的疲勞裂紋擴展行為。載荷比降低，da/dN曲線向高△K方向移動，并逐漸不出現(xiàn)疲勞裂紋的近門檻擴展階段；無論載荷比和含氫量的高低，穩(wěn)態(tài)裂紋擴展區(qū)的裂紋擴展行為符合Paris冪律關系，即da/dN=C(△K）^m；含氫量為110μg/g時，載荷比對穩(wěn)態(tài)裂紋擴展區(qū)的da/dN沒有影響；含氫280μg/g時，載荷比降低，穩(wěn)態(tài)裂紋擴展區(qū)的da/dN也降低；載荷比影響裂紋由近門檻擴展區(qū)進入穩(wěn)態(tài)裂紋擴展區(qū)的應力強度因子范圍△Kp和開始失穩(wěn)擴展的應力強度因子范圍△K1H。載荷比越小，△Kp和△K1H越大。

Abstract:The field strength distribution of the magnetic circuit vs the NdFeB permanents was calculated in the condition of the same magnetic structure. The permanents were possessed of the same volumes and configurations, but different performaces, and there was the same width of air-gap in the magnetic circuit. Their field strength magnitudes were compared and the factors of influence on magnetic field strength were analyzed . According the results it is necessary comprehensively to consider magnetic-energy-product, coercive force, remanence etc rather than to emphasize the materials with high magnetic-energy-product upon designing the permanent magnetic field for magnetic refrigeration so as to provide the proper basis for selecting materials in designing the magnetic field for room-temperature magnetic refrigirators.

Abstract:研究了1種新型的亞穩(wěn)定β鈦合金(Ti-B20)在不同熱處理制度下的顯微組織與拉伸和沖擊性能。結果表明，熱處理制度的改變能顯著影響該合金的顯微組織和強化行為。固溶溫度是影響合金時效后塑性的首要因素，而時效溫度是影響強度的主要原因。時效溫度降低，析出相更加細小，因此合金強度升高。而粗大的晶粒及連續(xù)的晶界容易產(chǎn)生應力集中，因此合金經(jīng)β固溶時效后具有較低的塑性和沖擊值。通過在β相變點下固溶，然后在550℃～600℃之間合適的溫度下時效處理，可以獲得強度，塑性和沖擊韌性的良好配合。

Abstract:The brazing of SiC particulate reinforced LY12 alloy matrix composite has been carried out by using the high-frequency induction vacuum brazing process with Al-28Cu-5Si-2Mg filler.The results showed that brazing temperature, holding time, SiC particle volume percentage and post heat treatment condition combine to influence the joint strength of SiCp/LY12. The SiC particles occur in the brazing seam and the distribution of SiC particles in the joint is not as uniform as that in the composites. Particle-poor zones in the joint exist near the base metal, and particle-rich zones exist in the center of the brazing seam. In addition, the results indicate that the failure of the composite is predominantly initiated by microcracks initiating at the SiC particle in the brazing seam and propagated along it with low energy.

Abstract:The characterizations of Ti/SnO2+Sb2O3/PbO2 anodes with SnO2+Sb2O3 as an intermediate layer obtained by way of a polymeric precursor, and using ethylene glycol, ethanol and n-butanol for different precursor solvents were studied. The microstructure, morphology of the SnO2+Sb2O3 layers derived from different precursor solvents and the top PbO2 active layers were examined using by XRD and ESEM. The lifetime and the electro-catalytic activity of Ti/SnO2+Sb2O3/PbO2 anodes with the intermediate layers prepared from different precursors were also assessed by the polarization method and the accelerated lifetime test in 1.0 mol/L H2SO4 solutions. The results showed that the microstructure and, morphology of the SnO2+Sb2O3 layers were correlated to precursor solvents. The intermediate layer made from a polymeric precursor was more compact, homogeneous, possess better surface smoothness, and a higher content of SnO2 and Sb2O3 as compared with that from the other solvents. Thus the Ti/SnO2+ Sb2O3/PbO2 anode prepared from the polymeric precursor had a longer lifetime than that with other solvents, but the intermediate layers prepared from different precursor solvents had little effect on the electro-catalytic activity of Ti/SnO2+Sb2O3/PbO2 anodes.

Abstract:采用快速凝固和熱壓的方法制備了p型熱電材料Fe0.92Mn0.08Six(x=1.9, 2.0, 2.1, 2.3, 2.5).X射線衍射分析表明,熱壓試樣退火24 h后,完全轉變?yōu)棣掳雽w相.所有試樣的致密度均高于90%.測量試樣的電學性能發(fā)現(xiàn),原料配比為Fe0.92Mn0.08Si2.1的試樣在整個測量溫度范圍內的功率因子最大,550℃時達到了400 μW·m-1·K-1以上.

Abstract:The effect of different stages of the partial melting process on the phase component and microstructure of (Bi,Pb)-2223/Ag strip was analyzed and compared to the normal two-stage heat treatment process. The results show that some of the (Bi,Pb)-2212 phase melted and decomposed into (Sr,Ca)2CuO3, (Sr,Ca)Cu2O3 and rich (Bi,Pb) liquid phase. At the same time, the (Sr,Ca)2CuO3 and (Sr,Ca)Cu2O3 phases grew rapidly. During cooling and phase formation, the (Sr,Ca)2CuO3 and (Sr,Ca)Cu2O3 phases stop growing when they reach a certain size and react with liquid phase to recreate the (Bi,Pb)-2212 phase with good orientation. At the phase formation stages, the (Bi,Pb)-2223 phase during transformation from the (Bi,Pb)-2212 phase inherits the good orientation of (Bi,Pb)-2212 phase. This results in an improvement in the texture and the density of the (Bi,Pb)-2223 phase which in turn results in an improvement of the critical current. The final strip made by the partial melting process has a critical current of 51 A (while the strip made by the normal two-stage heat treatment process have the lower critical current of 36 A). Thus the new method increases the critical current by about 40%.

Abstract:The structural and hydriding behaviours of the alloy LaMg11Ni after modification by mechanical grinding in tetrahydrofuran (THF) were investigated. The influence of mechanical grinding in THF on surface activation was evaluated by studying the hydrogen absorption/desorption kinetics. The alloy possesses high hydrogen storage and excellent kinetic behaviour, even at moderate temperatures. For the LaMg11Ni alloy milled in THF for 20 h, the hydrogen content of 3.4wt.% was obtained at 448 K and 3.2 MPa H2 after the initial exposure to hydrogen. An even higher hydrogen content of 3.65wt.% was obtained under the same conditions after several hydriding/ dehydriding cycles. Auger electron spectroscopy (AES) was used to determine the surface characteristics of the modified alloy. The modified alloy exhibits a rather high surface activity which improves with increase of milling time. According to XRD analysis the alloy modified by milling THF, show some degree of amorphousness.

Abstract:Nano-ZnO powder was prepared by using Zn(NO3)2 and (NH4)2CO3 as starting materials. The aggregation of nano-ZnO powder particles was studied by the Zeta potential system, infrared absorption spectra, XRD and SEM. The results showed that a suitable dispersant added to the ZnO precursor could increase the static potential of nano-ZnO powder, which would restrain aggregation of the precursor during the drying and calcining process. In this way, the dispersed state of the ZnO nano-powder is improved. The particle size of prepared ZnO powder is less than 20 nm. Secondary particle size is less than 80 nm.

Abstract:Single domain bulk Gd-Ba-Cu-O superconductors 17 mm in diameter have been successfully grown by powder-melt-processing (PMP) in air. The superconducting properties of Gd-Ba-Cu-O may be improved by substituting Gd2O3 for Gd211 addition and the cost of preparation can be decreased. However a solid solution of Gd-Ba forms in response to the inclusion of excess Gd2O3, and the superconducting properties of the bulk Gd-Ba-Cu-O decrease. The addition of 0.15 mol percent of Gd2O3 is found to be optimal and leads to a trapped field of 0.36 T at 77 K.

Abstract:分析了TC18鈦合金表面噴丸強化所產(chǎn)生的表面形貌、表面粗糙度、表面殘余應力和表面層殘余壓應力場變化及噴丸對拉-拉疲勞性能的影響,并用疲勞裂紋萌生的微細觀過程理論合理解釋了拉-拉疲勞極限的提高。結果表明:噴丸強化不僅能夠明顯延長TC18鈦合金的高周疲勞壽命,且能使1×107周次下的疲勞極限提高27%。

Abstract:A hydrosol of coexisting AgCl and Cu2+ was prepared by the precipitation method. The organosol of coexisting AgCl and Cu2+ was obtained by using oleic acid to extract and modify the nanoparticles in hydrosol, TEM photos showed that the AgCl nanoparticles were spherical in shape, and about 50nm in size. The particle size distribution was narrow and no agglomerates were observed. ED imaging indicated that the AgCl nanoparticles were polycrystalline in structure, and some of AgCl existed as monocrystalline particles. AgCl nanoparticles coated with oleic acid easily dissolved in weak polar solvents, but would not dissolve in polar solvents.

Abstract:Nanometer ZnO-base composite oxides were prepared by the inorganic salt sol-gel(ISG) method, and their structures were studied using XRD. The gas sensors were prepared from the nanometer ZnO-base composite oxides, and their sensing properties to different concentration of C2H5OH gases were investigated. A composition of Al/ZnO=1.5 mol% sensor shows a maximum sensitivity of 26 to 2 000 g/g C2H5OH. The composite oxide Sb/Al/ZnO=5?3?100(mol)% has good gas sensing properties over wider working temperature range. The physical and chemical adsorptions and the gas-sensing mechanism of the composite oxide Sb/Al/ZnO were discussed.