New Damage Localization Method for Bridges Using Vertical Support Reaction Data under Truck Load

The localization of damage for bridges to ensure their safety is investigated in this paper.Equivalent element concept is introduced into this study at the beginning.Support reaction data of each bearing under truck load are found to be able to lend themselves to indicate damage.A novel index termed as symmetrical support reaction difference index(SSRDI) is then developed.The reverse mapping between the local flexural stiffness change induced by damage and the SSRDI is generated.The proposed method based on SSRDI can be sensitive to tiny damages,and comparatively simple measurements are required during the application procedure.Another significant attraction of this method is that it can work in the presence of random uncertainties and actual support condition,which means it is suitable for real-world bridges.The effectiveness of the proposed method is demonstrated by numerical simulations performed on two kinds of bridges with reasonable damage severities.Its comparative advantage over the previous frequency method is also investigated.

Analysis of the interaction between bolt-reinforced rock and surface support in tunnels based on convergence-confinement method

To investigate the interaction of the bolt-reinforced rock and the surface support,an analytical model of the convergence-confinement type is proposed,considering the sequential installation of the fully grouted rockbolts and the surface support.The rock mass is assumed to be elastic-brittle-plastic material,obeying the linear Mohr-Coulomb criterion or the non-linear Hoek-Brown criterion.According to the strain states of the tunnel wall at bolt and surface support installation and the relative magnitude between the bolt length and the plastic depth during the whole process,six cases are categorized upon solving the problem.Each case is divided into three stages due to the different effects of the active rockbolts and the passive surface support.The fictitious pressure is introduced to quantify the threedimensional(3D)effect of the tunnel face,and thus,the actual physical location along the tunnel axis of the analytical section can be considered.By using the bolt-rock strain compatibility and the rocksurface support displacement compatibility conditions,the solutions of longitudinal tunnel displacement and the reaction pressure of surface support along the tunnel axis are obtained.The proposed analytical solutions are validated by a series of 3D numerical simulations.Extensive parametric studies are conducted to examine the effect of the typical parameters of rockbolts and surface support on the tunnel displacement and the reaction pressure of the surface support under different rock conditions.The results show that the rockbolts are more effective in controlling the tunnel displacement than the surface support,which should be installed as soon as possible with a suitable length.For tunnels excavated in weak rocks or with restricted displacement control requirements,the surface support should also be installed or closed timely with a certain stiffness.The proposed method provides a convenient alternative approach for the optimization of rockbolts and surface support at the preliminary stage of tunnel design.

Detection of PERV by polymerase chain reaction and its safety in bioartificial liver support system

瞄准：为了建立在中国试验性的微型猪检测猪的内长的制动火箭病毒(PERV ) 的一个方法并且在三评估 PERV 的安全，个人们基于猪的 hepatocytes 与简历 artificial 肝支持系统对待。方法：猪的 hepatocytes 与二阶段的灌注方法被孤立，在生物反应器然后有教养，它被半渗透的膜(0.2 microm ) 与病人的血浆通过被传播的腔分开。在 post-hemoperfusion 以后，病人的血为屏蔽被获得。另外，媒介的样品从实验室生物反应器的管腔内、额外的钠分隔空间收集了，文化上层清液在试管内被分析。病毒的序列的存在被聚合酶链反应(PCR ) 和反向的 transcriptase 聚合酶链反应(RT-PCR ) 估计。最后，在普通文化的上层清液的病毒的感染被暴露查明到胎儿的肝细胞。结果：PERV 特定作呕序列用 RT-PCR 在猪的 hepatocytes 被发现。并且从管腔内的、额外的钠样品和文化上层清液在所有样品被检测。然而，从主要猪的 hepatocytes 的文化上层清液(细胞的碎片变清) 没能感染人的胎儿的肝细胞。最后， RT-PCR 没检测感染在在各种各样的时间 post-hemoperfusion 从三个病人获得的血样品被发现的 PERV。结论：使用的试金特定、敏感，由第二 PCR 识别了。没有 mitogen 的刺激， PERV 能被免除在生物反应器有教养的 hepatocytes 并且不能被空纤维阻止半渗透的膜，显示在身体外的简历 artificial 肝的 PERV 安全的存在支持系统(EBLSS ) 。

Magneli phase titanium sub-oxide conductive ceramic Ti_nO_(2n-1) as support for electrocatalyst toward oxygen reduction reaction with high activity and stability

Magneli phase titanium sub-oxide conductive ceramic Tin O2n-1 was used as the support for Pt due to its excellent resistance to electrochemical oxidation, and Pt/Tin O2n-1 composites were prepared by the impregnation-reduction method. The electrochemical stability of Tin O2n-1 was investigated and the results show almost no change in the redox region after oxidation for 20 h at 1.2 V(vs NHE) in 0.5 mol/L H2SO4 aqueous solution. The catalytic activity and stability of the Pt/Tin O2n-1 toward the oxygen reduction reaction(ORR) in 0.5 mol/L H2SO4 solution were investigated through the accelerated aging tests(AAT), and the morphology of the catalysts before and after the AAT was observed by transmission electron microscopy. At the potential of 0.55 V(vs SCE), the specific kinetic current density of the ORR on the Pt/Tin O2n-1 is about 1.5 times that of the Pt/C. The LSV curves for the Pt/C shift negatively obviously with the half-wave potential shifting about 0.02 V after 8000 cycles AAT, while no obvious change takes place for the LSV curves for the Pt/Tin O2n-1. The Pt particles supported on the carbon aggregate obviously, while the morphology of the Pt supported on Tin O2n-1 remains almost unchanged, which contributes to the electrochemical surface area loss of Pt/C being about 2times that of the Pt/Tin O2n-1. The superior catalytic stability of Pt/Tin O2n-1 toward the ORR could be attributed to the excellent stability of the Tin O2n-1 and the electronic interaction between the metals and the support.

The Co_3O_4 nanosheet array as support for MoS_2 as highly efficient electrocatalysts for hydrogen evolution reaction

The electrochemical hydrogen evolution reaction（HER） on a non-precious electrocatalyst in an alkaline environment is of essential importance for future renewable energy. The design of advanced electrocatalysts for HER is the most important part to reduce the cost and to enhance the efficiency of water splitting. MoSis considered as one of the most promising electrocatalysts to replace the precious Pt catalyst.Herein, for the first time, we have successfully loaded MoSelectrocatalysts onto the CoOnanosheet array to catalyze HER with a low onset potential of6 mV. The high hydrogen evolution activity of MoSsupported on the CoOnanosheet array may be attributed to the increased active sites and the electronic interactions between MoSand CoO.

Novel Design Method of COG Measurement System Via Supporting Reaction Method

Center of gravity(COG)is an important parameter of projectiles and rockets,for which supporting reaction method(or support reaction method)is an important COG measurement method.Based on this supporting reaction method a novel design method is proposed to determine the key design parameters of the COG measurement system.The method can quantitatively analyze the influence of the design parameters on the COG accuracy,in the measurement system designed with supporting reaction method.Using the principle of static balance,the error propagation theory,and the system accuracy analysis method,the equal-range required sensor precision(RSP)surface and non-equal-range required sensor pair precision(RSPP)adapted surface are adopted.The influence of random errors(like sensor accuracy and distance calibration accuracy)is analyzed.The selection strategy of equal-range and non-equal-range sensors is chosen,and then the recommended calibration accuracy values are obtained.For the quality detection accuracy of±0.6 kg and the axial COG detection accuracy of±1.5 mm,the RSP surface is drawn by the proposed method,and the force sensor with±0.23 kg detection accuracy is selected.The experimental verification meets the accuracy requirements and verifies the effectiveness of the proposed design method for the system parameters of the COG measurement equipment.

Nation-Teflon bimembrane-supported palladium catalysts for Suzuki coupling reactions

Nation-Teflon bimembrane was used as an efficient support for the preparation and application of heterogeneous palladium catalysts. The supported palladium catalysts exhibit high activity and stability in the Suzuki cross-coupling of aryl bromides with arylboronic acids to afford the corresponding biaryls in good to excellent yields, and can be readily recovered and reused several times without significant loss of activity.

Direct asymmetric aldol reaction using MBHA resin-supported peptide containing L-proline unit

MBHA resin-supported tripeptide catalyst system containing L-proline unit has been developed for use in the direct asymmetric aldol reaction of acetone and aldehydes, which afford the corresponding products with satisfactory isolated yields and enantiomeric excesses. 2009 Hong Bin Zou. Published by E]sevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

间隔织物双剑杆织机平行打纬机构箱体的振动分析

针对双剑杆织机共轭凸轮与四连杆组合的平行打纬机构箱体随着织机转速的提高产生强烈振动,影响打纬精度和可靠性的问题,采用理论分析与虚拟仿真结合的方法对打纬机构及箱体进行动应力和振动特性研究。建立了平行打纬机构的动态静力分析方程,运用ADAMS软件对机构进行多体动力学仿真,求解箱体所受的支反力;构建箱体—弹簧阻尼—柔性基础的系统模型,分析箱体在竖直方向的受迫振动,并在仿真过程中探索减小箱体振动的方法。研究结果表明:摆臂轴孔处箱体所受支反力峰值最大,打纬推程阶段箱体的受力最为集中;当凸轮轴转速为260 r/min时齿轮啮合频率与箱体一阶固有频率相等,会产生共振,应避免使用这一转速工作;箱体在竖直方向上产生周期性振动,增加螺栓个数和附加动力减震器有助于改善箱体的振动特性,振幅分别减少38%和23%。

In situ IR, pulse reaction and TPD-ITD study of catalytic performance of room-temperature carbon monoxide oxidation on supported gold catalysts

With in situ IR, two different CO adsorption bands were detected on various chemical state gold catalysts. One band is attributed to the linear CO on an oxidized gold catalyst(2100 cm -1 ), the other one is ascribed to the bridged CO on metallic gold (2085 cm -1 ). CO pulse reaction showed that Au/Fe 2O 3 catalyst had a room temperature activity even in the presence of moisture. The produced CO 2 was detained and more easily desorbed from supported gold catalyst than support oxide. TPD IDT results indicated that the O - 2 superoxide ions are the possible active oxygen species.

玻纤负载α-Fe_(2)O_(3)/CuFe_(2)O_(4)异质结薄膜的制备 及其催化性能

为了克服传统芬顿催化剂的降解速率慢、pH适用范围窄、难回收等缺点,采用浸涂溶胶-凝胶法制备了玻璃纤维负载的α-Fe_(2)O_(3)/CuFe_(2)O_(4)异质结薄膜(FCGF),对其结构、形态和化学组成进行表征,并将其用于亚甲基蓝的光芬顿催化降解,考察其催化活性、pH值适用性和重复使用稳定性。结果表明:CuFe2O4颗粒生长在α-Fe_(2)O_(3)颗粒表面,形成α-Fe_(2)O_(3)/CuFe_(2)O_(4)异质结;在模拟太阳光辐射条件下,加入2 g FCGF和20 mmol/L的H_(2)O_(2),50 mL质量浓度为30 mg/L的MB溶液在40 min后降解率达到97%,而在相同条件下加入α-Fe_(2)O_(3)与CuFe_(2)O_(4)降解率分别为20%和30%,其催化活性的增强可归因于异质结光催化剂产生的光诱导电位差驱动的光生载流子的有效分离;同时,FCGF在宽pH范围显示出较高活性,pH=10时,MB溶液40 min后降解效率仍达到63%;FCGF具有良好的稳定性,5次循环后其催化性能没有衰减,反应40 min后MB降解率仍可达97%。

不同支撑材料对Na-Mn_(2)O_(3)载氧体化学链甲烷氧化偶联性能的影响

采用浸渍法制备了3种具有稳定多孔结构的支撑材料(SiO_(2),Mg O,TiO_(2))负载的Na-Mn_(2)O_(3)载氧体,采用XRD、N2吸附-脱附、SEM、H_(2)-TPR等方法对载氧体的微观结构进行表征,研究了不同还原温度下各种支撑材料对Na-Mn_(2)O_(3)载氧体化学链甲烷氧化偶联性能的影响。实验结果表明,支撑材料主要影响载氧体的催化活性和储氧能力,SiO_(2)比MgO和TiO_(2)具有更发达的孔结构和更高的比表面积,Na-Mn_(2)O_(3)/Si O_(2)的催化性能最佳,在800℃下C2选择性达74.25%、C2产率为14.12%;Na-Mn_(2)O_(3)/SiO_(2)和Na-Mn_(2)O_(3)/MgO具有较好的结构稳定性,活性组分具有较好的晶格氧稳定性;MgO与Mn_(2)O_(3)的前体在载氧体制备过程中化学反应最显著,形成了Mg_(6)MnO_(8)并产生较高的储氧能力。

缺陷诱导电子-金属载体相互作用加速固液界面Fenton反应

水体污染物的深度氧化去除是环境领域的研究热点.芬顿反应作为典型的高级氧化技术(AOPs)被广泛用于水中有机污染物的去除.对于非均相芬顿反应,催化剂表面Fe^(3+)/Fe^(2+)的循环是决定其活性的主要因素.Fe^(3+)还原的关键在于接受额外电子,因此电子是提升芬顿反应效率的关键.传统非均相催化剂由于表面“惰性”,限制了固液界面电子的传递,导致Fe^(3+)/Fe^(2+)的循环效率处于较低的水平.因此设计一种具有高效界面电子传递性能的催化剂对提高芬顿反应效率至关重要.本文通过简易的酸处理法,成功合成了富含缺陷的NH_(2)-UiO-66(d-NU)材料,并将其用于水中有机污染物的去除.核磁共振氢谱(1H NMR)、热重分析(TG)、傅里叶红外光谱(FTIR)和X射线吸收精细结构(EXAFS)等多种表征证明了酸处理诱导NH_(2)-UiO-66上缺陷结构的形成.光电流、电化学阻抗和时间分辨瞬态荧光光谱结果表明,缺陷结构的形成可有效促进光生电子-空穴的分离.与不含缺陷的NH_(2)-UiO-66(NU)相比,d-NU在光芬顿氧化过程中表现出更优的4-CP去除效率,其降解动力学速率常数是NU的11倍,极大地加速了4-CP的去除进程.实验及理论计算结果表明缺陷的形成破坏了Zr配位结构的几何对称性,导致Zr位点电荷密度的不对称分布.该不对称结构有利于Fe^(3+)富集到Zr-O簇上,并通过电子-金属-载体相互作用(EMSI)形成Zr‒O‒Fe桥键,促进催化剂固液界面电子的传输,提高催化剂界面Fe^(3+)/Fe^(2+)的循环效率.实际应用实验结果表明,在d-NU/Fe^(3+)/H_(2)O_(2)光芬顿体系中,环境水体中常见无机离子对4-CP的降解影响很小.同时,d-NU/Fe^(3+)/H_(2)O_(2)光芬顿体系能够对多种有机污染物保持较高的去除效率,且催化活性在经过10次循环后没有明显的衰减,说明d-NU具有较好的抗离子干扰性、降解多种污染物的普适性和结构稳定性.通过液相色谱-质谱监测确定了4-CP的降解途径,并通过毒理学模拟4-CP及其降解生成中间体的生物毒性,结果表明,4-CP降解过程中形成的中间体的综合毒性低于4-CP.综上,本研究揭示了MOF基芬顿催化剂中金属氧簇的配位关系对芬顿反应的作用机制,提出了富含缺陷的MOFs与Fe^(3+)之间电子转移的作用机制,为进一步开发高效芬顿催化剂提供了新思路.

贵金属催化剂在CO-PROX反应中的应用进展

CO-PROX反应具有操作简单、安全实用、价格低廉等特点。从应用于CO-PROX反应中贵金属催化剂的活性组分、助剂、载体及整体式催化剂方面介绍了贵金属催化剂在CO-PROX反应中的应用进展,提出控制粒子尺寸、提高分散度,选择具有还原性及特定形貌的金属氧化物为载体,掺杂助剂修饰等可有效提高催化性能。整体式催化剂具有床层压降低、传质效率高等优点,适合应用于高空速、大通量的氢能-燃料电池系统中。并对应用于CO-PROX反应催化剂的发展趋势进行展望。

基于SOR理论的产前心理弹性支持对瘢痕妊娠再次剖宫产产妇心理弹性及应对方式的影响

目的 探究基于刺激-机体-反应(SOR)理论的产前心理弹性支持对瘢痕妊娠再次剖宫产产妇的影响。方法 选取2022年1月至2023年6月南京医科大学附属南京医院收治的120例拟行剖宫产的瘢痕妊娠产妇作为研究对象,采用随机数字表法将其分为对照组(60例)与观察组(60例)。对照组实施常规护理干预,观察组实施基于SOR理论的产前心理弹性支持干预,两组均连续接受8周干预。比较两组干预前、干预8周后心理弹性水平、应对方式。结果 干预8周后,两组焦虑控制、抑郁抑制、精神状态、不安抑制,以及量表总分均高于干预前,且观察组高于对照组(P<0.05);两组计划-准备、灵性-积极应对得分高于干预前,且观察组高于对照组(P<0.05);两组逃避评分低于干预前,且观察组低于对照组(P<0.05)。结论 基于SOR理论的产前心理弹性支持可提高瘢痕妊娠再次剖宫产产妇的心理弹性水平,促进其采用积极的应对方式。

大跨度管桁架屋盖整体提升对下部混凝土结构的影响研究

为研究张家口奥体中心游泳馆大跨度管桁架屋盖在提升过程中对下部混凝土结构的影响,分析了不同数量、不同布置方式的提升架对混凝土楼板和框架梁挠度影响。设计5种不同提升架模型,研究其受力特性。研究结果表明,提升架模型d在风荷载作用下的水平位移为其他模型的2倍,模型e 4个吊点在相同竖向荷载作用下传递至支座的轴力相差较大。提升架吊索失效不利于提升架受力,应予防治。当提升架支座反力作用于梁板时,只对受力点影响较大,对其余部位影响较小,且多受力点共同作用对梁板的影响为多个单受力点对梁板影响的线性叠加。薄弱区框架梁承受提升架支座反力时,可在梁下部加设临时钢柱支撑,加设支撑后梁最大挠度减小约50%。

CuAg双金属催化剂的性能及在锌空气电池中的应用

采用化学还原法两步合成了CuAg催化剂。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)等手段对CuAg催化剂进行表征分析,并对其进行循环伏安(CV)、线性扫描伏安(LSV)等电化学测试。结果表明:在氧饱和的碱性电解质中,CuAg氧还原反应是4电子过程,随着Ag含量的增加,催化活性逐渐增强。将CuAg负载碳黑上,催化性能得到了进一步提高,CuAg/C的起始电位为0.815 V(vs.RHE),Tafel斜率为84.92 mV/(°)。将催化剂应用于锌空气电池时,电池功率密度达到128.96 mW/cm^(2),极限放电比容量达到792 mAh/g,在5 mA/cm^(2)充、放电循环下具有长期循环稳定性。

Pd基MoO_(x)催化剂中金属与载体的相互作用及其对Heck反应的影响

钯(Pd)催化的Heck反应是合成中构建碳-碳键的有效方法之一。金属-载体相互作用(MSI)对于非均相催化剂在某些工业过程中由于金属活性位点暴露或堵塞而显著提高或降低催化性能具有重要意义。本文合成了Pd基MoO_(x)催化剂,利用XRD、XPS、Raman等表征研究了在不同氧化还原处理条件下,钯纳米粒子与氧化钼层的金属-载体相互作用(MSI)在碘苯和丙烯酸甲酯的Heck反应中的性能影响。研究发现Pd/MoO_(3)在氢气条件下的部分还原导致MoO_(x)物种迁移到Pd-NPs的表面并形成包封结构,涂层可能通过空气煅烧重新暴露,MSI导致Pd/MoO_(3)在Heck反应中的催化性能降低。本研究证明了平衡金属-载体相互作用在实际催化剂设计中的重要性,以实现贵金属催化剂在催化Heck反应中的更高利用率。

连续梁拱组合桥梁边中跨比影响分析

连续梁拱组合桥梁主梁和拱肋协同受力,整体刚度大、跨越能力强。以三跨连续梁拱组合桥梁为工程背景,分析了边中跨比对桥梁内力、变形、支反力、自振频率、稳定等方面的影响。分析发现:桥梁主梁和拱肋的内力、变形,主梁边支点的支反力随边中跨比的增大而增大,且在恒载作用下边中跨比0.400时边支点出现负反力;桥梁自振频率随边中跨比的增大而减小;桥梁施工阶段稳定系数随边中跨比的增大而减小,成桥状态稳定系数随边中跨比的增大而增大,但稳定系数变化率均较小;连续梁拱组合桥梁的合理边中跨比建议在0.425~0.500之间。