In Situ Synthesis of Nanocrystalline Intermetallic Compound Layer during Surface Mechanical Attrition Treatment of Zirconium

The surface mechanical attrition treatment (SMAT) technique was developed to synthesize a nanocrystalline (NC) layer on the surface of metallic materials for upgrading their overall properties and performance. In this paper, by means of SMAT to a pure zirconium plate at the room temperature, repetitive multidirectional peening of steel shots (composition (wt%): 1C, l.SCr, base Fe) severely deformed the surface layer. A NC surface layer consisting of the intermetallic compound FeCr was fabricated on the surface of the zirconium. The microstructure characterization of the surface layer was performed by using X-ray diffraction analysis, optical microscopy, scanning and transmission electron microscopy observations. The NC surface layer was about 25 urn thick and consisted of the intermetallic compound FeCr with an average grain size of 25±10 nm. The deformation-induced fast diffusion of Fe and Cr from the steel shots into Zr occurred during SMAT, leading to the formation of intermetallic compound. In addition, the NC surface layer exhibited an ultrahigh nanohardness of 10.2 GPa.

Analysis of Valence Electron Structure in Compound Layer of Steel 42CrMo Plasma Nitrided with Rare Earth Addition

The valence electron structure (VES) in compound layer of steel plasma-nitrided at 560°C with rare earth (RE) addition was calculated based on the empirical electron theory (EET) of solids and molecules and BLD method. The results show that the presence of RE atoms diffused into surface layer leads to an increase of phase structure factor, which explains the catalyzing and micro-alloying effects of RE.

Numerical Prediction of Compound Layer Growth of Steel En40B during Plasma Nitriding

This paper deals with the kinetics of compound layer growth of steel En40B plasmas nitrided at 520°C for different time and establishes the corresponding mathematical model based on the thermodynamics and kinetics of nitrogen diffusion process. The results show that the compound layer consists of dual phases e (Fe2-3N) and / (Fe4N) and its thickness increases with increasing nitriding time. The calculated data indicate that the critical concentration between compound layer and diffusion one is about 0.82wt%. The computer simulation results demonstrate that predicted compound layer thickness agrees with the measured data.

Effect of the Compound Layer of Plasma Nitriding on Thermal Fatigue Behavior of 4Cr5MoSiV1 Die Steel

With the Uddeholm self restricted method, the effect of compound layer of plasma nitriding on thermal fatigue behavior of 4Cr5MoSiV1 steel was studied by the way of adding Ar during plasma nitriding to remove the compound layer. The results show that the compound layer of plasma nitriding can delay the nucleation of heat cracks and hold back the propagation of heat cracks from surface to substrate because of its high hardness and strength. On the other land, the heat checking expands faster with the compound layer on the surface than that without it. After 3000 cycles of thermal fatigue test, both heat cracks with the compound layer are wider than the another without compound layer and the number of heat cracks of the former is more from the view of cross section.

Thickness of compound layer in steel-aluminum solid to liquid bonding

The bonding of solid steel plate to liquid aluminum was studied using rapid solidification. The surface of solid steel plate was defatted, descaled, immersed (in K2ZrF6 flux aqueous solution) and stoved. In order to determine the thickness of Fe-A1 compound layer at the interface of steel-aluminum solid to liquid bonding under rapid solidification, the interface of bonding plate was investigated by SEM (Scanning Electron Microscope) experiment. The relationship between bonding parameters (such as preheat temperature of steel plate, temperature of aluminum liquid and bonding time) and thickness of Fe-Al compound layer at the interface was established by artificial neural networks (ANN) perfectly. The maximum of relative error between the output and the desired output of the ANN is only 5.4%. From the bonding parameters for the largest interfacial shear strength of bonding plate (226℃ for preheat temperature of steel plate, 723 ℃ for temperature of aluminum liquid and 15.8 s for bonding time), the reasonable thickness of Fe-A1 compound layer 10.8 μm was got.

Structure and antibacterial activity of new layered perovskite compounds

New layered perovskite compounds, AgxNa2-xLa2Ti3O10 (x=0.2, 0.3 and 0.5) were synthesized by an ion-exchange reaction of Na2La2Ti3O10 with AgNO3 solution and characterized by energy dispersive X-ray analysis(EDX), X-ray diffractometry(XRD), scanning electron microscopy(SEM) and X-ray photoelectron spectroscopy(XPS). The ion-exchange processes were optimized, and the antibacterial activity, light permanency and water-resistance were evaluated. Surprisedly, no significant changes in crystal structure of Na2La2Ti3O10 are found by the exchange of silver ions. The Ag0.3Na1.7La2Ti3O10 particles conglomerate obviously with irregular shape and size. Ag0.3Na1.7La2Ti3O10, possessing the minimum inhibitory concentrations(MICs) against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) of 180 mg/L and 240 mg/L, has high antibacterial activity, good light permanency and water-resistance. The ionic state silver in AgxNa2-xLa2Ti3O10 is the antibacterial active component.

Synthesis and antibacterial activity of new layered perovskite compounds,Ag_xNa_(2-x)La_2Ti_3O_(10)

有 Ruddlesden 扑扑儿(R-P ) 的三种新分层的 perovskite 混合物分阶段执行， AgxNa2 ? xLa2Ti3O10 (x = 0.2， 0.3 和 0.5 ) ，被 Na2La2Ti3O10 的离子交换反应与 AgNO3 综合答案。混合物的结构被 EDX 和 XRD 描绘，并且他们的抗菌活性和轻抵抗的性质被评估。结果显示 AgxNa2 的分子式 ? xLa2Ti3O10 (x = 0.2， 0.3 和 0.5 ) 被证实，并且 Na2La2Ti3O10 的晶体结构不是，这显然由银离子的交换影响了。对大肠杆菌关口 i 的 Ag0.3Na1.7La2Ti3O10 的最小的禁止的集中(MIC )(E。关口 i ) ，葡萄球菌 aureus (S。aureus ) 分别地，当它的褪色没在 24 h 光老化试验以后被观察时，是 180 μ g /mL 和 240 μ g /mL。

Low contact resistivity between Ni/Au and p-GaN through thin heavily Mg-doped p-GaN and p-InGaN compound contact layer

Thin heavily Mg-doped In Ga N and Ga N compound contact layer is used to form Ni/Au Ohmic contact to p-Ga N.The growth conditions of the compound contact layer and its effect on the performance of Ni/Au Ohmic contact to p-Ga N are investigated. It is confirmed that the specific contact resistivity can be lowered nearly two orders by optimizing the growth conditions of compound contact layer. When the flow rate ratio between Mg and Ga gas sources of p++-In Ga N layer is 10.6% and the thickness of p++-In Ga N layer is 3 nm, the lowest specific contact resistivity of 3.98×10-5?·cm2is achieved. In addition, the experimental results indicate that the specific contact resistivity can be further lowered to1.07×10-7?·cm2by optimizing the alloying annealing temperature to 520℃ .

Compound buried layer SOI high voltage device with a step buried oxide

A silicon-on-insulator (SOI) high performance lateral double-diffusion metal oxide semiconductor (LDMOS) on a compound buried layer (CBL) with a step buried oxide (SBO CBL SOI) is proposed.The step buried oxide locates holes in the top interface of the upper buried oxide (UBO) layer.Furthermore,holes with high density are collected in the interface between the polysilicon layer and the lower buried oxide (LBO) layer.Consequently,the electric fields in both the thin LBO and the thick UBO are enhanced by these holes,leading to an improved breakdown voltage.The breakdown voltage of the SBO CBL SOI LDMOS increases to 847 V from the 477 V of a conventional SOI with the same thicknesses of SOI layer and the buried oxide layer.Moreover,SBO CBL SOI can also reduce the self-heating effect.

Preparation and Characterization of Layered Compound Zirconium Bis(monohydrogenphosphate) Intercalated with Rare Earth Complex

Layered compound zirconium his（monohydrogenphosphate）（α-ZrP） intercalated with rare earth complex Eu（DBM）3phen was prepared. The pre-intercalation of p-methoxyaniline into α-ZrP makes the interlayer separation large enough to exchange PMA with europium complex, thus, the luminescent assembly was prepared. This was confirmed by X-ray diffraction, UV-visible spectra and elemental analysis. The fluorescence spectra and lifetime of the assembly were also presented.

Quantum Size Effect of the Magnetism of an Electron in a Metal Layer of the Layered Compounds M/I/M/I…

The energies and the magnetization of an electron in a piece of metal in the structure of Metal/Insulator/Metal/Insulator…(M/I/M/I…), in a magne tic field, at high temperature, and in range of quantum size thickness of the pi ece of metal layer have been obtained. The results show that when the thickness of the metal layer becomes smaller, the orbital magnetism of the charged particl es which collide with the wall of the metal layer is to vary from diamagnetism t o paramagnetism. The smaller the thickness of the metal layer becomes, the more particles will collide with the boundary of the metal layer, and then the parama gnetism becomes stronger. Finally, when the thickness of the metal layer becomes very small (<100 nm), all of the orbital diamagnetism will reverse to paramagn etism, and then the paramagnetization will be almost a maximum constant.

Synthesis and Crystal Structure of a Novel Compound:[Nd_3(OH)_7(O_2CC_6H_4SO_3)(H_2O)]_n·nH_2O with a Pillar-layered Structure

A novel Nd(Ⅲ) compound,[Nd3(OH)7(O2CC6H4SO3)(H2O)]n·nH2O 1,has been synthesized by the hydrothermal reaction of Nd2O3 and 3-sulfobenzoic acid monosodium salt. It was characterized by IR spectroscopy,elemental analysis,thermogravimetric analysis and single-crystal X-ray diffraction. It crystallizes in monoclinic,space group P21/c with a = 13.024(3),b = 10.961(2),c = 12.792(3) ,β = 91.271(3)°,V = 1825.6(7) 3,Z = 4,Mr = 787.97,Dc = 2.867 g/cm3,μ = 8.584 mm-1,F(000) = 1460,S = 1.035,R = 0.0442 and wR = 0.1166 (I > 2σ(I)). In this compound,the cross-linkage of Nd atoms by bridging hydroxy groups results in a Nd-O inorganic <200> layer,and such layers are linked by the 3-O3S-C6H4-CO2 dianions into a pillar-layered structure. The lattice water molecules are located in the cavity.

Direct Process to Prepare Crystallized Freestanding Membranes of Hydroxyapatite Using Sacrificial Layer of Barium-Compounds

Freestanding membrane (FSM) of hydroxyapatite (HA) is a thin sheet of pure HA without any supporting substrates. Our original preparation process of FSM of HA had three steps: The first was the deposition of HA layer on sacrificial layer of solvent-soluble materials, the second was separation of FSM of HA by means of dissolution of sacrificial layer, and the third was post-annealing to crystallize FSM of HA. To date, the post-annealing process was a serious bottleneck of productivity owing to its too long time. In this short report, we proposed a novel sacrificial layer, heatproof and water-soluble Ba-compound, which makes the direct deposition of crystallized HA possible due to its heatproof property because the problem on the original process was that the previous sacrificial layers have no heatproof property and HA layer should be deposited as amorphous. We can deposit the Ba-compound sacrificial layer only in 1 hour followed with the direct deposition of crystallized HA layer, substituting the 20 hours of post-annealing. The FSM of HA was separated successfully from the substrate by means of dissolution of Ba-compound with water. Our novel process can shrink the process time by 19 hours.

In Situ Synthesis of Titanium Nickel Intermetallic Compounds Layer and TiN Coating By Laser Cladding

Laser cladding,together with laser nitriding was used to synthesize a titanium nickel intermetallic compound layer on the nickel substrate and a TiN coating on the cladding layer. During the laser cladding, Ti and Ni powders were blown into the melting pool by a six-hole coaxial nozzle powder injection system. Exothermic reactions between Ti and Ni took place in the melting pool, and a cladding layer of titanium nickel intermetallic compounds was produced. Laser nitriding in a nitrogen-rich atmosphere followed the production of the cladding layer, and formed a golden yellow TiN layer over it. An optical and a scanning electron microscope were used to investigate the microstructures and measure the thicknesses of the cladding layer and the TiN layer. Phase identification was carried out by XRD. For the nitriding sample, the microhardness profile of the clad layer was tested. The optimal process parameters of the in situ synthesis of titanium nickel intermetallic compounds were obtained.

紫花苜蓿中黄酮类化合物分离及特殊显色反应研究

本研究旨在分离紫花苜蓿中的黄酮类化合物,并进行特殊显色反应相关研究。研究人员通过植物采集和样品制备,获得了紫花苜蓿的植物材料。研究人员采用萃取方法和分离富集方法,成功地从植物材料中提取出黄酮类化合物。其中,柱色谱技术和液液萃取是本研究中主要的分离富集手段。通过黄铜色素的纯化步骤,获得了高纯度的黄酮类化合物。在黄酮色素的紫外光谱分析中,实验过程中采用了先进的光谱技术,得到了详细的实验结果。通过实验结果的分析,确定了所得黄酮类化合物的结构和纯度,为后续研究奠定了坚实的基础。综合研究结果,本研究成功地实现了紫花苜蓿中黄酮类化合物的分离、富集和特殊显色反应的研究目标。所获得的高纯度黄酮类化合物为进一步的生物活性研究提供了有力的实验基础,为紫花苜蓿及相关植物资源的开发利用提供了重要的科学依据。

高用胶量厚橡胶层二系叠层弹簧橡胶堆制品硫化成型工艺研究及硫化时间确定

研究硫化成型工艺对高用胶量厚橡胶层二系叠层弹簧橡胶堆制品质量的影响,并探究其硫化时间的确认方法。结果表明:采用压铸硫化成型方式完全可以满足该制品生产需求,且产品质量稳定性和生产合格率较高;根据产品胶料差示扫描量热分析、核磁共振法交联密度分析和刚度分析结果,采用胶层临界气泡点时间确定的产品硫化时间适宜,产品得到充分硫化。

NiCo-LDH材料的形貌分析与电化学性能研究

采用一步水热法在泡沫镍上合成镍钴层状双金属氢氧化物(NiCo-LDH)电极材料,用扫描电镜分析电极材料的微观形貌,X射线衍射仪分析电极材料的物相,并在不同扫描速率以及不同电流密度下NiCo-LDH纳米材料进行了电化学性能测试。结果表明:随着尿素含量的增加,NiCo-LDH的形貌由六角片状、草丛状,最后形成片层上带有针状形貌。扫描速率为10 mV·s^(-1)时,在CV曲线中可以清晰地看到氧化还原峰。电极在0.30~0.35V之间的充放电曲线出现对称的充放电平台,说明其充放电容量和充放电时间均较优,该复合材料的电容性能良好。

Mg1/Al1060真空扩散焊接头微观组织演变及性能分析

利用真空扩散焊接技术,实现了工业纯镁Mg1与工业纯铝Al1060的连接.采用扫描电镜、能谱仪、万能力学试验机、显微硬度测试仪、电化学工作站等对扩散反应层的微观组织、物相成分及其性能进行研究.结果表明,Mg/Al真空扩散焊会在接合处生成由镁铝系金属间化合物组成的扩散反应层,随着保温时间延长,反应层的厚度逐渐增加,微观组织形态发生明显变化.扩散初期反应层呈现为单层结构,Mg_(2)Al_(3)相会在接合界面优先析出.保温时间达到60 min时,界面会生成Mg_(17)Al_(12)新相层.当保温时间延长至90 min时,反应层演变为三层结构,由Mg_(2)Al_(3)层、Mg_(17)Al_(12)层、(Mg_(17)Al_(12)共晶+Mg基固溶体)层组成;随着保温时间延长,接头的剪切强度呈先升高后降低的趋势,在保温60 min时可承受的剪切力达到_(12)45.7 N,断裂发生在靠近铝侧的Mg_(2)Al_(3)反应层处.各焊接层的显微硬度明显高于镁铝母材,Mg_(2)Al_(3)层具有最高的显微硬度,达到了320.6 HV.反应层腐蚀速率由大到小的顺序为Mg1、(Mg_(17)Al_(12)共晶+Mg基固溶体)层、Mg_(2)Al_(3)层、Mg_(17)Al_(12)层、Al1060.

多工作面连续开采地表沉陷与强矿震联动响应规律

深部矿井多工作面大空间开采导致大能量强矿震事件频发,同时地表伴随剧烈的下沉变形,掌握具体地层条件下地表移动与强矿震时空分布响应规律对于深部矿井动力灾害防控意义重大。以兖州矿区东滩煤矿63_(上)04,63_(上)05,63_(上)06工作面为工程背景,基于关键层理论与复合破断原理,对东滩煤矿复杂地层进行了科学划分,现场实测了深井厚硬岩层下多工作面开采地表沉降规律及强矿震时空分布特征,分析了多工作面连续开采下关键层组运移演化规律,揭示了关键层组破断演化、地表沉陷规律与大能量强矿震分布的联动效应。研究结果表明:(1)东滩煤矿六采区地层可以划分出4个关键层组,每个关键层组包含一层关键层和若干坚硬岩层,相比单一关键层,关键层组发生复合破断时的矿震能量更高、破断步距更大,对上覆岩层的运移及地表下沉影响也更为突出。(2)地表沉陷观测结果显示,63_(上)04,63_(上)05工作面开采结束,地表下沉系数分别为0.189,0.458;63上06工作面当前已开采808.29 m,地表下沉系数为0.492,受多关键层组地质赋存特征影响,东滩煤矿六采区地表下沉系数远小于兖州矿区其他矿井平均地表下沉系数(0.75~0.85),地表未达到充分采动,下沉趋势为:无明显下沉–下沉空间显著–下沉空间逐渐增大。(3)矿震监测结果显示,63上04工作面开采时,大能量强矿震事件主要集中在低位关键层组Ⅰ,Ⅱ层位,随着多工作面连续开采,大能量强矿震逐渐向高位转移,逐渐集中至关键层组Ⅱ,Ⅲ层位。(4)由地表沉陷及大能量强矿震实测数据可知,东滩煤矿六采区多工作面连续开采下关键层组复合破断覆岩结构呈“断悬”结构–“铰接”结构交替上升,逐层演化过程验证了覆岩运动、地表沉陷及大能量强矿震3者之间存在一定的联动效应。研究成果可对类似工程地质条件下多关键层组复合破断研究及大能量强矿震预控提供一定参考。

铆钉高度对胶铆复合连接接头性能的影响

以1mm厚的DC04钢板与2mm厚的5052铝合金板为铆接对象,在两板之间添加厚度为0.1mm、0.2mm、0.3mm的结构胶,并分别用4mm、5mm和6mm高的铆钉制备自冲铆接接头。通过拉伸剪切试验分析失效形式、观察不同接头的截面成形,并通过电化学腐蚀试验研究添加结构胶对接头的耐蚀性影响。结果表明:铆钉高度一定时,胶厚为0.1mm的接头拉剪强度最大,胶厚的增加会减小接头的内锁值。不同高度的铆钉会造成接头不同的失效形式,4mm高的铆钉接头的主要失效形式为胶层失效后上下板分离;5mm高的铆钉接头失效形式是铆钉脱离下板失效;6mm高的铆钉失效形式为上板撕裂,铆钉脱离上板失效。添加结构胶可以提高接头的耐蚀性,且随着胶厚的增加,耐蚀性也随之增加。