A PENNY-SHAPED CRACK IN A MAGNETOELECTROELASTIC LAYER UNDER RADIAL SHEAR IMPACT LOADING

This paper analyzes the dynamic magnetoelectroelastic behavior induced by a penny- shaped crack in a magnetoelectroelastic layer.The crack surfaces are subjected to only radial shear impact loading.The Laplace and Hankel transform techniques are employed to reduce the prob- lem to solving a Fredholm integral equation.The dynamic stress intensity factor is obtained and numerically calculated for different layer heights.And the corresponding static solution is given by simple analysis.It is seen that the dynamic stress intensity factor for cracks in a magnetoelec- troelastic layer has the same expression as that in a purely elastic material.And the influences of layer height on both the dynamic and static stress intensity factors are insignificant as h/a>2.     

Metal-free cascade boron-heteroatom addition and alkylation with diazo compounds

Transition metal-catalyzed carbene transfer reaction is one of the most notable advances for C-C bond formation reactionsduring the past decade,which has been widely employed in the preparation of C3-substituted indoles,Here,we described an efficient exa mple of catalyst-and metal-free aminobo ration of alkynes and C—C bond formation with diazo compounds to produce C3-substituted indoles,Diverse alkynyla nilines and diazo compounds ca n be utilized for this tandem transfo rmation under mild reaction conditions,re sulting in broad functional group co mpatibility.Additionally,this metal-free strategy can be extended to construct substituted benzofurans.     

基于主动偏振光的潜指纹偏振成像检测方法研究

作为一种无损检测方法,光学检验法是多种潜指纹检测方法中的首选。在面对越来越复杂的应用场景时,传统光学检验法往往效果不佳。然而偏振成像探测技术不仅能够获得目标的强度和光谱等信息,而且还能够得到偏振度和偏振角等反映目标表面细节特征的偏振信息,因此可以提高潜指纹检测效果。利用偏振成像技术的优势,开展了基于主动偏振光的潜指纹偏振成像检测实验研究,获取了指纹图像数据并对其进行了分析。结果表明,与一般的强度成像相比,本文方法所得到的潜指纹偏振参量图像质量更高,获取的图像更清晰,细节信息更丰富。     

Stress Relaxation Behaviors of Monocrystalline Silicon Coated with Amorphous SiO2 Film:A Molecular Dynamics Study

Long-lasting constant loading commonly exists in silicon-based microelectronic con-tact,as well as the chemical mechanical polishing area.In this work,the stres...     

Development of a Genus-Universal Nucleotide Signature for the Identification and Supervision of Ephedra-Containing Products

Ephedra plants generally contain ephedrine alkaloids, which are the critical precursor compounds of methamphetamine (METH). METH could cause serious physical and mental damage, and therefore Ephedra materials are strictly in supervision internationally. However, unlawful utilization of Ephedra herbs and its products still exist. Thus, it is imperative to establish a universal method for monitoring Ephedra ingredients in complex mixtures and processed products. In this study, 224 ITS2 sequences representing 59 taxa within Ephedra were collected, and a 23-bp genus-level nucleotide signature (GTCCGGTCCGCCTCGGCGGTGCG) was developed for the identification of the whole genus. The specific primers MH-1F/1R were designed, and 125 individuals of twelve Ephedra species/varieties were gathered for applicability verification of the nucleotide signature. Additionally, seven batches of Chinese patent medicines containing Ephedra herbs were used to test the application of the nucleotide signature in complex and highly processed materials. The results demonstrated that the 23-bp molecular marker was unique to Ephedra and conserved within the genus. It can be successfully utilized for the detection of Ephedra components in complex preparations and processed products with severe DNA degradation. The method developed in this study could undoubtedly serve as a strong support for the supervision of illegal circulation of Ephedra-containing products.     

用于雷达的LDMOS微波功率放大器设计

硅LDMOS晶体管以其大输出功率和高效率等优点作为微波功率放大器广泛应用于雷达发射机中.在大信号S参数无法获得而厂家提供的1710 MHz～2110 MHz范围内的源阻抗和负载阻抗参数又不能用时,利用一公司的ADS软件,采用负载牵引法得到了输入和输出阻抗.在对晶体管绝对稳定性分析的基础上,运用共轭匹配,成功设计出P-1大于30W、功率增益在1580MHz～1650 MHz频率范围内、增益保持在30dB以上和PAE大于30%的2级LDMOS微波功率放大器.同时,得到了最终的版图并且运用MOMENTUM对它进行了2.5D仿真,得到了理想的结果.     

Photocatalytic Carboxylation of Phenyl Halides with CO2 by Metal-Organic Frameworks Materials

In this work,important commercial pharmaceutical intermediates,phenylpropionic acid compounds,are successfully obtained by catalyzing the reaction of carbon dioxide with phenyl halides using MOF-5,a typical metal-organic framework(MOF)material.The influence of temperature,pressure,catalyst type and light on the reaction is investigated,and a 90.3%selectivity towards fluorophenylpropionic acid is reached.Significantly,the catalysts are effective for varied benzyl compounds containing different substituent groups.The catalysts are stable and remain active after three cycles.     

Synthesis and Structure–Activity Relationship Studies of Benzimidazole-4,7-dione-Based P2X3 Receptor Antagonists as Novel Anti-Nociceptive Agents

P2X3 receptors (P2X3R) are ATP-gated ion channels predominantly expressed in C- and Aδ-fiber primary afferent neurons and have been introduced as a novel therapeutic target for neurological disorders, including neuropathic pain and chronic cough. Because of its localized distribution, antagonism of P2X3R has been thoroughly considered, and the avoidance of issues related to CNS side effects has been proven in clinical trials. In this article, benzimidazole-4,7-dione-based derivatives were introduced as a new chemical entity for the development of P2X3R antagonists. Starting from the discovery of a hit compound from the screening of 8364 random library compounds in the Korea Chemical Bank, which had an IC₅₀ value of 1030 nM, studies of structure–activity and structure–property relationships enabled further optimization toward improving the antagonistic activities as well as the drug’s physicochemical properties, including metabolic stability. As for the results, the final optimized compound 14h was developed with an IC₅₀ value of 375 nM at P2X3R with more than 23-fold selectivity versus P2X2/3R, along with properties of metabolic stability and improved solubility. In neuropathic pain animal models evoked by either nerve ligation or chemotherapeutics in male Sprague-Dawley rats, compound 14h showed anti-nociceptive effects through an increase in the mechanical withdrawal threshold as measured by von Frey filament following intravenous administration.     

基于LabVIEW的超导磁体数采与测控系统研究

根据研制的大口径、高场强的超导强磁装置的特点,选择基于LabVIEW的数据采集和测控系统。低温传感器共六支,分别安装于磁体氦槽和冷屏不同位置,其中碳电阻温度计Cernox三支,铂电阻温度计Pt100两支、Pt1000一只,用于监测磁体温度;超导氦液面计一个,用于监测氦液面高度;根据磁体参数匹配研制了一套可调励磁速率的磁体专用直流电源及其失超保护系统,保证磁体安全运行。所有数据通过NI公司内插DAQ6251数据采集卡的PX I采集,用LabVIEW编写数据采集程序和人机界面。     

结合地物分类的湿地蒸散量定量遥感集成模型

湿地蒸散发量是湿地水量支出的重要组成部分。利用遥感技术可以合理有效地计算出地形复杂的湿地的蒸散发量。将遥感图像分类技术与定量遥感蒸散发模型结合起来,考虑各类地物不同的蒸散发源和水热传输机制,建立了集成模型,分析和计算了湿地主要地物的蒸散发量。通过对各地物类的样区平均蒸散发量与实测数据进行比较,证明结合地物分类的湿地蒸散发量计算集成模型能够取得很好的结果。