Indirect tension test of epoxy asphalt mixtureusing microstructural finite-element model

A finite-element model of the thermosetting epoxy asphalt mixture（EAM） microstructure is developed to simulate the indirect tension test（IDT）.Image techniques are used to capture the EAM microstructure which is divided into two phases：aggregates and mastic.A viscoelastic constitutive relationship,which is obtained from the results of a creep test,is used to represent the mastic phase at intermittent temperatures.Model simulation results of the stiffness modulus in IDT compare favorably with experimental data.Different loading directions and velocities are employed in order to account for their influence on the modulus and the localized stress of the microstructure model.It is pointed out that the modulus is not consistent when the loading direction changes since the heterogeneous distribution of the mixture internal structure,and the loading velocity affects the localized stress as a result of the viscoelasticity of the mastic.The study results can provide a theoretical basis for the finite-element method,which can be extended to the numerical simulations of asphalt mixture micromechanical behavior.

Correlations between direct and indirect strength test methods

The difficulties associated with performing direct compression strength tests on rocks lead to the development of indirect test methods for the rock strength assessment. Indirect test methods are simple, more economical, less time-consuming, and easily adaptable to the field. The main aim of this study was to derive correlations between direct and indirect test methods for basalt and rhyolite rock types from Carlin trend deposits in Nevada. In the destructive methods, point load index, block punch index, and splitting tensile strength tests are performed. In the non-destructive methods, Schmidt hammer and ultrasonic pulse velocity tests are performed. Correlations between the direct and indirect compression strength tests are developed using linear and nonlinear regression analysis methods. The results show that the splitting tensile strength has the best correlation with the uniaxial compression strength.Furthermore, the Poisson's ratio has no correlation with any of the direct and indirect test results.

Effects of 3D deformation and nonlinear stress–strain relationship on the Brazilian test for a transversely isotropic rock

To improve the accuracy of indirect tensile strength for a transversely isotropic rock in the Brazilian test, this study considered the three-dimensional (3D) deformation and the nonlinear stress–strain relationship. A parametric study of a numerical Brazilian test was performed for a general range of elastic constants, revealing that the 3D modeling evaluated the indirect tensile strength up to 40% higher than the plane stress modeling. For the actual Asan gneiss, the 3D model evaluated the indirect tensile strength up to 10% higher and slightly enhanced the accuracy of deformation estimation compared with the plane stress model. The nonlinearity in stress–strain curve of Asan gneiss under uniaxial compression was then considered, such that the evaluated indirect tensile strength was affected by up to 10% and its anisotropy agreed well with the physical intuition. The estimation of deformation was significantly enhanced. The further validation on the nonlinear model is expected as future research.

人红细胞类同种特异性自身抗体的血清学试验分析与研究

目的近年来,实验室临床样本的检测中,类同种特异性自身抗体(以下简称“类抗体”)样本检出率不断增加。抗球蛋白微柱凝集卡技术逐渐普及应用,进一步提高了类抗体检出率。为了研究类抗体实验室检测特点,探讨类抗体输血原则,本文进行了回顾性数据分析,为产生类抗体的患者提供有效的检测方法和临床建议。方法对160名产生类抗体的受检者进行详细的性别、年龄、诊断、血清学试验等回顾性分析。分析实验所得数据,找寻相关规律。结果类抗体最常见特异性为RH血型类抗体,包括类抗-Ce,类抗-Ec和类抗-D等占94.48%。CCDee分型是类抗体受检者最常见分型。血清微柱凝集卡法检测类抗体反应性较强(类抗体计分值最高:7.16分)。血清试管抗球蛋白法反应强度差异性最为显著,鉴别类抗体特异性较好。结论鉴定类抗体特异性比较困难,建议选择多种鉴定方法。微柱凝集卡法检测类抗体的反应性较强,抗球蛋白法鉴别类抗体特异性较好,建议此两种方法联合使用。输血治疗时应尽量避开类抗体特异性,输注相应抗原阴性的红细胞。

竞争ELISA和间接ELISA方法应用于牛布鲁氏菌病净化的研究

旨在评价竞争ELISA方法和间接ELISA方法联合使用在布鲁氏菌病(以下简称“布病”)净化中的效果,为布病防控提供技术支撑。采用本实验室开发的动物布鲁氏菌病竞争ELSIA(cELISA)抗体检测试剂盒、牛布鲁氏菌病间接ELISA(iELISA)抗体检测试剂盒及微量法补体结合试验(mCFT),对西北某牛场3 271份牛血清进行检测。本研究采用cELISA初筛、iELISA确诊的净化策略,对检测阳性牛进行淘汰,可疑牛和阴性牛在完全消毒后隔离饲养,并在前一次检测后每隔1个月重新对群体采样,进行多次连续的“检—淘”策略,在群体的个体阳性率低于2%或全部转阴后使用微量补体结合试验(mCFT)进行验证。并在群体全部转阴后继续检测2个月后确定净化结果。结果显示,首次检测阳性率35.36%的感染群体实施本净化策略后,在第1个月阳性率下降至25.41%,第2个月下降至7.16%,第3个月下降为1.86%,到第4个月则实现了布病阳性群体的全面转阴,mCFT验证个体阴性率100%。此后持续检测2个月,个体阳性率均为0,至此实现了感染群体的布病净化,使得群体内近一半的牛免于扑杀,大大减少了经济损失。综上发现,将cELISA用于布病初筛,iELISA用于布病确诊的联合使用,经多次连续检测并结合常规的隔离消毒措施,可以在短时间内实现对于布病感染群体的全面净化。

土体抗拉强度试验研究方法的综述

土体抗拉强度比抗压和抗剪强度数值更小,因此时常被忽略,造成理论及试验的落后。文中系统归纳了土体抗拉强度的间接和直接方法,对比分析了现有试验方法的优缺点,结果表明:(1)土体抗拉强度的单轴拉伸方法按照力的加载方向可以分为垂直法和水平法,而垂直法中土样破坏前上半部分的重量会影响试验的准确性;(2)常用的土样固定方式有粘结、锚固、摩擦力和夹持,它们各有优势,但夹持较前三者更便捷和可操作。最后,提出水平单轴拉伸试验的后续仍需优化的问题。如制样脱模中土样的损耗、土样受拉段应力分布差,无法适用于大骨料砾质土、土样固定方式繁琐、土样与平台间的摩擦力难以消除等。

成型方式对应力吸收层沥青混合料性能的影响

开展了旋转压实与马歇尔击实成型对应力吸收层沥青混合料体积和力学性能的影响分析。试验结果表明,应力吸收层配合比设计中可用马歇尔击实50次代替旋转压实50次成型试件,旋转压实试件与马歇尔试件的劈裂抗拉强度、贯入应力均具有良好相关性,换算系数分别为1.347和0.910。提出了基于马歇尔击实方法的应力吸收层设计要求,可更好地进行配合比设计和工地现场质量控制。

空间站高温材料科学实验系统热控设计及验证

中国空间站高温材料科学实验系统(HTMSES)是中国新一代的可长期在轨运行的综合型多功能空间材料实验装置,其组成复杂、布局紧凑、实验温度高、部组件散热困难,使热控设计难度较大。基于液冷主动控温、辐射间接控温、结构热控一体化协同优化设计等多种思路对热控组件进行设计,有效解决热控难题。利用有限元分析软件计算科学实验系统热设计的温度结果;然后开展加热实验对热设计方案进行验证。数据显示HTMSES在提供材料制备所需要的最严苛实验工况(1200℃)情况下,各关键部件处于友好的温度范围内,其中电机最高温度为42.2℃,编码器最高温度为40.6℃,丝杠最高温度为62.4℃,滑块最高温度为59.6℃,导轨最高温度为57.3℃,科学实验系统皮肤可触及部位最高温度为31.6℃,各温度结果均满足热控指标要求,表明设计方案合理可行,为同类型设备热设计提供了一种设计思路和参考依据。

沥青混合料低温劈裂虚拟试验影响因素研究

基于离散元法(discrete element method,DEM)建立沥青混合料二维劈裂(indirect tensile,IDT)试验模型,研究集料模型、集料形状、空隙率,以及加载方位角等因素对混合料低温劈裂虚拟试验结果(劈裂强度和最大水平拉应力)的影响。结果表明:沥青混合料低温虚拟劈裂试验时,集料模型对数值模拟计算效率、内部结构中的接触力链和裂纹扩展路径等有很大影响;实际边界模型较等效椭圆形与等效多边形模型其数值模拟结果变异性较小;空隙率大小对劈裂强度及水平向最大拉应力有显著影响,随空隙率的增大两者均有不同程度的减小;不同加载方位角下的劈裂试验数值模拟结果呈各向异性。

基于车辆振动响应间接识别桥梁频率的模型试验研究

为证明采用过桥车辆振动信号可以识别桥梁多阶振动频率,搭建了缩尺车桥耦合振动模型进行试验,研究了各类影响因素下采用二轴试验车对桥梁频率的识别效果.首先,介绍了缩尺车桥耦合振动的模型梁和试验车;其次,分析了传感器分别安装于模型梁、试验车底座和试验车顶座的振动信号,并对比这3种振动信号对桥梁频率的识别效果;最后,研究了悬架刚度、车身质量、路面粗糙度和运营车流激励对试验车间接识别桥梁频率的影响.结果表明,试验车底座的振动传感器可以识别得到桥梁前3阶竖向振动频率和前2阶扭转振动频率,与安装于桥梁振动传感器的频谱大致相同,说明该传感器不受车体振动影响;试验车顶座的振动传感器可以准确识别桥梁第一阶竖向振动频率,但是桥梁高阶频率受到车体自身振动频率干扰较难识别.各类影响因素主要影响试验车顶座振动传感器的桥梁频率识别效果,对试验车底座振动传感器的桥梁频率识别效果影响很小,证明了所设计试验车在间接测量桥梁动力特性的优越性.

基于信号分离方法的桥梁车载振动传感器移动监测技术研究

为更好地从过桥车辆振动响应中识别桥梁频率,对比研究快速傅里叶变换FFT、变分模态分解VMD和连续小波变换CWT三种信号处理方法的应用效果。首先,介绍FFT、VMD和CWT三种信号处理方法的理论基础和应用流程;其次,通过车桥耦合数值分析算例,对比三种方法在利用车辆振动加速度响应识别桥梁多阶频率的效果;最后,通过缩尺车桥耦合模型试验,进一步研究三种方法的应用效果。

肺炎支原体感染临床微生物检验的快速诊断技术价值研究

研究临床在肺炎支原体感染检验中运用微生物检验快速诊断技术的价值。以遵义市红花岗区人民医院在2022年1月—2023年2月接诊肺炎支原体感染患者76例为研究对象,均进行间接免疫荧光法检验以及快速血清学检验。分析检验价值。结果显示,对比诊断阳性率,间接免疫荧光法检验明显高于快速血清学检验(P<0.05);对比不同年龄段检验结果,间接免疫荧光法检验在检验准确率上明显高于快速血清学检验(P<0.05);对比不同病程患者检验结果,病程1周内患者在间接免疫荧光法检验准确率上高于快速血清学检验,病程在1周以上患者两种检验方式均具有较高准确率;对比两种检验方式用时,快速血清学检验用时明显短于间接免疫荧光法检验(P<0.05)。研究发现,临床在开展肺炎支原体感染检验中,间接免疫荧光法检验与快速血清学检验各具优势,在实际检验过程中可以结合患者特点进行合理选择,以提升肺炎支原体感染检验效率。

基于小型化模块相位噪声的间接测试方法

收发电路模块的本振信号质量对系统的整体性能有重要影响。小型化模块由于尺寸的限制,无法在本振的输出端设置测试端口,因此无法直接在本振的输出端准确地测试相位噪声。提出了一种针对小型化收发电路模块本振信号相位噪声的间接测试方法,该方法需要测试模块的输入/输出信号的功率、相位噪声以及整个收发通路的增益和噪声系数,通过公式计算得到本振信号的相位噪声。采用此方法对小型化收发电路模块进行测试,将得到的相位噪声结果与器件指标进行对比,两者高度一致,从而验证了间接测试方法的正确性和有效性。

基于间接拉伸试验的沥青-集料界面黏结性研究

为研究沥青-集料界面黏结性能,选取70号基质沥青及SBS改性沥青混合料在不同温度、老化、水分条件下进行间接拉伸试验,通过分析其峰值力、断裂能、开裂容忍指数(CT)来表征沥青与集料间的黏结性,揭示各影响因素对沥青-集料的影响特征。结果表明,沥青混合料的峰值力随温度升高而降低,但断裂能及CT指数随温度升高而增大,温度在本质上改变了沥青的黏弹性质,从而使得沥青与集料的界面黏结性能发生显著改变。随着老化程度的加剧,沥青混合料峰值力增大而断裂能、CT指数降低,在长期老化条件下,70号基质沥青与SBS改性沥青的峰值力分别增长31.1%,15.4%,而断裂能分别减少27.6%,19.1%,老化作用提升了沥青混合料的黏结强度,但抗裂性及延展性遭到削弱。长期高温浸水处理后,沥青混合料的峰值力、断裂能、CT指数均发生显著下降,在高温浸水4 d后,70号基质沥青和SBS改性沥青混合料的峰值力分别下降48.2%,33.1%,CT指数分别降低67.7%,32.5%,水分侵入沥青-集料界面造成了沥青膜的剥离,严重影响沥青-集料界面的黏结性。

Significance of antineutrophil cytoplasmic antibody in adult patients with Henoch-Schnlein purpura presenting mainly with gastrointestinal symptoms

AIM： To test the clinical significance of antineutrophil cytoplasmic antibody （ANCA） in evaluation of adult Henoch-Schonlein purpura （HSP） patients presenting mainly with abdominal symptoms. METHODS： Twenty-eight consecutive HSP patients who presented predominantly with abdominal symptoms were enrolled in this study. Control subjects included 27 ageand sex-matched patients with peptic ulcer disease, colon cancer, acute gastroenteritis, irritable bowel syndrome and colonic polyps. ANCA was measured by indirect immunofluorescence （IIF） in all patients, and follow-up ELISA was performed in patients with positive IIF tests. RESULTS： ANCA was detected in 9 HSP patients by IIF （2 were positive for c-ANCA and 7 were positive for p-ANCA）. No ANCA was found in the control group. The sensitivity and specificity of a positive ANCA test （either c- or p-ANCA） were 32.1% and 100% respectively. Only one out of the 9 patients with positive ANCA by IIF had positive ANCA by ELISA and the antigen was myeloperoxidase （MPO）. The patients positive for ANCA had higher HSP clinical scores, and were more likely to have renal function impairment. Patients with late purpura development were also associated with more severe clinical manifestations. CONCLUSION： A positive ANCA test is associated with more severe symptoms in HSP. After inflammatory bowel disease is excluded, a positive ANCA test provides a clue to the diagnosis of HSP presenting predominantly with abdominal symptoms.

Application of an indirect immunofluorescent staining method for detection of Salmonella enteritidis in paraffin slices and antigen location in infected duck tissues

AIM： To detect Salmonella enteritidis （S. enteritidis） in paraffin slices and antigen location in infected duck tissues. METHODS： The rabbits were immunized with purified bacillus to obtain S. enteritidis-specific antibody, which were then extracted by the caprylic-ammonium sulphate method, purified through High-Q columns. An indirect immuno-fluorescent staining method （IFA） was established to detect the S. enteritidis antigen in paraffin slices. Detected S. enteritidis in each organ tissue of ducklings experimentally infected with S. enteritidis. RESULTS： The gland of Garder, heart, kidney, spleen, liver, brain, ileum, jejunum, bursa of Fabricius from S. enteritidis experimentally infected ducklings were positive or strongly positive, and the S. enteritidis antigen mainly distributed in the infected cell cytoplasm.CONCLUSION： IFA is an intuitionist, sensitive and specific method in detecting S. enteritidis antigen in paraffin wax slices, and it is a good method in diagnosis and antigen location of S. enteritidis. We also conclude that the gland of Garder, heart, kidney, spleen, liver, ileum, jejunum are target organs in S. enteritidis infections of duck, and S. enteritidis is an intracellular parasitic bacterium.

齐帕特罗残留检测酶联免疫吸附试验方法的建立及优化

为建立检测齐帕特罗(ZIL)残留物的间接竞争酶联免疫吸附试验(ic-ELISA),以获得的抗ZIL兔多抗血清为基础,以制备的完全抗原为包被源,通过优化反应条件,建立了检测ZIL残留物的ic-ELISA检测方法。结果表明,兔血清最佳稀释比例为1∶6000,抗原最佳包被浓度为2μg/mL,半数抑制浓度(IC 50)为0.317 ng/mL,线性检测范围(IC 20~IC 80)为0.136~1.181 ng/mL,最低检测限(LOD,IC 10)为0.081 ng/mL。经优化后,检测体系最佳pH为7.4,盐浓度≤0.4 mol/L,甲醇、乙醇、丙酮和和DMSO的含量≤5%,乙腈含量≤10%,且检测基质中牛尿液浓度≤15%时能够获得较高的检测灵敏度,并且该检测方法具有良好的稳定性和特异性,批内和批间重复试验样品添加回收率分别为101%~112%和101%~120%,变异系数均低于10%,检测结果与HPLC-MS检测结果的相关系数为R 2=0.9906。该检测方法检测速度快、灵敏度强、准确性高、重复性好、检出限低,适用于ZIL残留的高通量检测和现场快速筛查。

Overview of Standardized Testing System for ESL Students in U.S. Kindergarten Thru Grade 12 Public Schools

A comprehensive overview of standardized testing system for ESL （English as a Second Language） students in U.S kindergarten thru grade 12 public school system is reviewed within the context of basis on federal and state laws, as well as instructional basis. Identification process of LEP （Limited English Proficient） students via nomination, testing and testing criteria to be identified as LEP, hence ESL if placed in the program is defined in detail Standardized testing process of these students based on the federal AYP （Adequate Yearly Progress） measures through regular state standardized tests depending on three types of instructional program that LEP student is placed in the school that are Bilingual Education Program, ESL Program, and Two-Way Immersion Dual Language Programs are described. Standardized testing process of these students based on the federal AYP measures through other means if exempted from regular state standardized tests such as LAT （Linguistically Accommodated Testing） and the conditions to be exempted are discussed in detail. Holistically rated English Language Proficiency Assessments that are implemented to fulfill federal AMAOs （Annual Measurable Achievement Objectives） measures are defined briefly. Physical features of LAT test as well as direct and indirect accommodations for LAT reading, mathematics and science tests are defined via the accommodation needed and the type of assistance provided. Lastly, testing criteria to exit LEP status and other issues concerning exiting LEP status are reviewed

基于三维随机细观模型的沥青混合料断裂行为研究

为了从细观层次研究沥青混合料内部损伤失效机理,采用三维激光扫描技术获取真实集料三维形态信息,根据其形态特征参数提出一种三维随机凹凸型集料建模方法,并构建三维虚拟集料库。使用Monte Carlo方法构建AC-13三维虚拟试件,利用多刚体动力学方法模拟试件压实过程。采用截面算法获取沥青混合料二维细观模型,在模型有效性和准确性得到验证的基础上利用该模型开展虚拟间接拉伸试验,运用内聚力模型和广义Maxwell模型表征沥青混合料断裂行为和黏弹特性,引入断裂损伤指标D_(m)量化其内部损伤,并利用虚拟试验探讨温度对沥青混合料断裂行为的影响。结果表明,在宏观层次,主裂纹不受温度影响,沿着粗集料的边界逐渐发展直至试件破坏;在细观层次,相较于沥青内部界面单元,沥青-集料界面单元更易出现损伤,更快达到损伤失效点,且受温度影响显著。

基于截短绵羊鹦鹉热衣原体r MOMP_(183-390)蛋白的间接ELISA检测方法建立与应用

为建立绵羊鹦鹉热衣原体(Cp)间接ELISA抗体检测方法,本实验将编码Cp主要外膜蛋白MOMP的omp A基因序列按大肠杆菌密码子偏好性优化后,合成质粒p ET-28b(+)-omp A,另外设计特异性引物,分别将omp A截短克隆至p ET-28b(+)载体中构建重组表达质粒p ET-28b(+)-omp A_(1-182)和p ET-28b(+)-omp A_(183-390),测序鉴定正确后分别转化至E.coli BL21(DE3)感受态细胞中,经IPTG诱导并纯化后,经western blot鉴定3个重组蛋白,结果显示,重组MOMP_(183-390)蛋白(r MOMP_(183-390))表达效果最好。以r MOMP_(183-390)作为包被抗原,采用方阵滴定法优化各反应条件,初步建立了检测Cp抗体的间接ELISA方法。采用建立的该方法检测羊痘病毒、布鲁氏菌、羊口疮病毒、小反刍兽疫病毒、口蹄疫病毒等羊临床常见病的阳性羊血清,结果显示,除Cp外,该方法与其他阳性羊血清均无交叉反应,特异性强;将Cp阳性血清2倍倍比稀释(1∶50~1∶6400)后采用该方法检测,结果显示,当Cp阳性血清稀释达1∶1600时,仍可检测到抗体,敏感性高;批内、批间重复性试验结果显示,变异系数均小于10%。采用本研究建立的ELISA方法,以及间接血凝(IHA)试验和western blot分别检测随机选取的120份临床羊血清,结果显示该方法与IHA、western blot的总符合率分别为85%和91.67%;进一步采用建立的间接ELISA方法检测381份吉林省5家羊场的绵羊血清样品,结果显示阳性率为22.83%(87/381)。本研究建立的绵羊Cp omp A重组截短蛋白的间接ELISA抗体检测方法敏感性高、特异性强、重复性好,为Cp临床样品检测及流行病学调查提供了可靠的技术手段。