基于移动平台的自动测试系统

本文首先阐述了网络化测控仪器的产生背景,分析了传统的自动测试系统的不足之处。针对传统的缺陷设计了新型的自动测试系统。介绍了在网络化测量中的基于无线移动平台的网络接入技术,提出了使用嵌入式控制系统的无线网络接入方案,给出了基于GPRS的自动测试系统架构图及其软件的组成与性能。设计制作了网络接入的协议转换装置。编写了网络通路建立软件。新系统在一定程度上解决了自动测试系统的灵活性难题,很好地解决多种工业总线的系统集成问题,大大丰富了工业总线的体系。     

电调衰减器的自动测量法

文中介绍了电调衰减器的自动测量方法。通过上位机程序对功率计及接口电路的控制,可自动测得电调衰减器一系列衰减量对应的控制码。该方法提高了测量结果的准确性,并缩短了测量所需时间。     

Vortical structures and wakes of a sphere in homogeneous and density stratified fluid

Vortical structures and wakes of bluff bodies in homogenous and stratified environment are common and important in ocean engineering.Based on the Boussinesq app...     

The grain-boundary resistance of CeO2 ceramics: A combined microscopy-spectroscopy-simulation study of a dilute solution

Weakly acceptor-doped ceria ceramics were characterized structurally and compositionally with advanced transmission electron microscopy (TEM) techniques and electrically with electrochemical impedance spectroscopy (EIS). The grain boundaries studied with TEM were found to be free of second phases. The impedance spectra, acquired in the range 703 ≤ T/K ≤ 893 in air, showed several arcs that were analyzed in terms of bulk, grain-boundary, and electrode responses. We ascribed the grain-boundary resistance to the presence of space-charge layers. Continuum-level simulations were used to calculate charge-carrier distributions (of acceptor cations, oxygen vacancies, and electrons) in these space-charge layers. The acceptor cations were assumed to be mobile at high (sintering) temperatures but immobile at the temperatures of the EIS measurements. Space-charge formation was assumed to be driven by the segregation of oxygen vacancies to the grain-boundary core. Comparisons of data from the simulations and from the EIS measurements yielded space-charge potentials and the segregation energy of vacancies to the grain-boundary core. The space-charge potentials from the simulations are compared with values obtained by applying the standard, analytical (Mott–Schottky and Gouy–Chapman) expressions. The importance of modelling space-charge layers from the thermodynamic level is demonstrated.     

Defect chemistry of A site nonstoichiometry and the resulting dielectric behaviors in SrxTi0.985(Nb2/3Zn1/3)0.015O3 ceramics

Defect chemistry of Sr site nonstoichiometry in Sr_xTi_0.985(Nb_2/3Zn_1/3)_0.015O₃ ceramics and the resulting effects on the structure and dielectric behavior are systematically investigated by experiment and density functional theory (DFT) methods. The results indicate that, appropriate Sr deficiency benefits the dielectric properties and grain growth due to the creation of Sr vacancy. While Sr excess deteriorates the dielectric properties and inhibits the grain growth by forming a Ruddlesden-Popper structure. In Sr-deficient sample, more point defects arise and aggregate into defect clusters, resulting in great changes in local structures and the enhancement of dielectric properties. The Sr vacancy benefits the generation of oxygen vacancy, thus facilitating the localization of electrons and the decrease in dielectric loss. Besides, the electronic polarization and structural polarization are also improved by Sr vacancy and the resultant oxygen vacancy, leading to the further enhanced dielectric properties. These findings may facilitate the development of defect engineering towards novel multifunctional electronic materials.     

工程机械4WS电液控制系统试验装置的工作原理

简要分析了4轮转向试验平台的工作原理,其中包括加载系统、气动振动系统、转向系统和电器控制系统的工作原理。并对其可行性进行了分析。     

An investigation into the antiwear,antioxidation, and anticorrosion behaviour of some derivatives of 2,5-dimercapto -1,3,4-thiadiaxole

It appears that the comprehensive performance of 2,5-dimercapto-1,3,4-thiadiazole derivatives is dependent upon both the type and the structure of the chains attached to the carbon atoms in the 2 and 5 positions of the thiadiazole ring. For the side chain of the monosulphide type R-S-, the type and location of substituents have an important influence on additive performance. In the case of the side chain of the disulphide type, X-SS-, the presence of the phosphorus-containing group has a significant effect on multifunctionality.     

THZ531 Induces a State of BRCAness in Multiple Myeloma Cells: Synthetic Lethality with Combination Treatment of THZ 531 with DNA Repair Inhibitors

Multiple myeloma (MM) is a hematological disease marked by abnormal growth of B cells in bone marrow. Inherent chromosomal instability and DNA damage are major hallmarks of MM, which implicates an aberrant DNA repair mechanism. Studies have implicated a role for CDK12 in the control of expression of DNA damage response genes. In this study, we examined the effect of a small molecule inhibitor of CDK12–THZ531 on MM cells. Treatment of MM cells with THZ531 led to heightened cell death accompanied by an extensive effect on gene expression changes. In particular, we observed downregulation of genes involved in DNA repair pathways. With this insight, we extended our study to identify synthetic lethal mechanisms that could be exploited for the treatment of MM cells. Combination of THZ531 with either DNA-PK inhibitor (KU-0060648) or PARP inhibitor (Olaparib) led to synergistic cell death. In addition, combination treatment of THZ531 with Olaparib significantly reduced tumor burden in animal models. Our findings suggest that using a CDK12 inhibitor in combination with other DNA repair inhibitors may establish an effective therapeutic regimen to benefit myeloma patients.     

Event vertex and time reconstruction in large-volume liquid scintillator detectors

Large-volume liquid scintillator detectors with ultra-low background levels have been widely used to study neutrino physics and search for dark matter. Event ve...     

Optimization of energy-group structure for LWR high-fidelity neutronics calculation based on the contributon theory

ABSTRACT

Deterministic high-fidelity neutronics calculation is to solve the neutron transport equation using the multi-group (MG) nuclear data libraries. The energy-group structure (ES) in MG nuclear data libraries has a significant impact on the precision and efficiency of neutronics calculation. Therefore, to meet the requirement of high precision and efficiency for high-fidelity neutronics calculation, the contributon theory is adopted to select the optimal ESs for the high-fidelity neutronics code NECP-X which is developed by Nuclear Engineering Computational Physics (NECP) lab. at Xi’an Jiaotong University (XJTU). By combining the contributon theory with the exhaustive searching method, the optimal ESs can be selected effectively. Two optimal ESs named NECP-69 and NECP-47 are obtained and the nuclear data processing code NECP-Atlas developed by NECP lab. is utilized to generate the corresponding MG nuclear data libraries for NECP-X. The neutronics parameters of the MOX pin cell problems and the VERA benchmarks are evaluated. The numerical results show that more precise neutronics parameters are obtained based on the optimal ESs compared with those based on the conventional WIMS-69 and HELIOS-47 for NECP-X.