Stabilization and Consistency for Subtracted and Unsubtracted QCD Sum Rules for 0^＋＋ Scalar Glueball

Based on a semi-classical expansion for quantum chromodynamics in the instanton liquid background, the correlation function of the 0^＋＋ scalar glueball current is calculated. Besides the pure classical and quantum contributions, the contributions arising from the interactions between the classical instanton fields and quantum gluon ones come into play. It turns out that the latter contributions have a great role not only in making the stabilization of the subtracted and unsubtracted Laplace-transformed QCD sum rules for 0^＋＋ scalar glueball, but also in bring back the consistency between the two related sum rules, or equivalently between the QCD asymptotic expression and low energy theorem. The result for the scalar glueball mass is predicted to be mG= 1.35 GeV.     

AAS法测定人眼晶体中铜锌锰镁钙钠钾

微量元素和人体健康关系的研究已成为当前医学学科引人注目的一个新领域。白内障是老年人常见的一种多发性眼病,为探明其原因,需要分析眼睛晶体中某些微量元素的含量。本文用原子吸收光谱法测定了100例白内障患者眼睛晶体中的Cu、Zn、Mn、     

Pt修饰和反应气氛对富铝Cu-Beta分子筛NH_3-SCR反应性能的影响

富铝Cu-Beta分子筛具有优异的低温NH_3-SCR性能,在汽车尾气脱硝中具有潜在的应用前景.我们考察了H_2O、CO_2、丙烯等气氛对富铝Cu-Beta分子筛NH_3-SCR反应性能的影响.发现H_2O会降低催化剂的低温活性,CO_2则提高低温活性,丙烯对中、低温活性均有明显抑制作用.固体13C核磁共振显示丙烯在分子筛上形成链状脂肪烃积碳,导致催化剂的活性降低.Pt修饰使丙烯存在下低温NH_3-SCR活性有所提高,但在中高温度下会催化NH_3氧化产生大量的N_2O和NO,从而降低了NO转化率.电子顺磁共振(EPR)和紫外-可见(UV-Vis)光谱研究表明,Pt的引入使部分孤立铜离子转化为簇状多聚态铜离子,会进一步加剧高温NH_3氧化反应的发生,进而降低了催化剂的活性.     

PBX-9404炸药冲击起爆的一维数值模拟

对Tang模型的阈值函数进行修改,给出了新的能量传递过程特征时间。将修改后的Tang模型加入到二维有限元动力分析程序DYNA2D中,计算PBX-9404炸药的冲击起爆过程,并与Forest-Fire模型和点火-燃烧-快反应模型的计算结果进行比较,结果表明:新模型的适用范围更广,而且p(t)曲线的波形、VN点和cj点的压力幅值都较理想。     

JO-9159炸药的初始密度对爆轰波反应区宽度影响的实验研究

 利用电磁法对两种具有不同初始密度的JO-9159炸药的爆轰反应区宽度进行了测量。结果表明,对于JO-9159这种爆轰反应区非常窄的炸药,既使爆轰达到了定常状态,化学反应仍然与炸药的初始物理状态有关。     

水溶液中碳纳米管的表面增强拉曼光谱研究

合成了碳纳米管和金纳米颗粒的复合物, 测量了水溶液相中复合物的表面增强拉曼光谱, 结果表明, 碳纳米管的巯基化修饰可以提高碳纳米管与金纳米颗粒复合的效率, 随着金纳米颗粒负载量的增加, 碳纳米管的拉曼信号逐渐增强. 加入己二胺分子可以减小金纳米颗粒之间的距离使表面增强效应更显著, 碳纳米管的拉曼光谱得到进一步的增强. 还可进一步在复合体系中加入对巯基苯胺和罗丹明B等小分子拉曼探针, 利用金纳米颗粒的表面增强效应, 这种多元复合体系有望作为多通道拉曼成像探针材料.     

Numerical and analytical investigations for the SOI LDMOS with alternated high-k dielectric and step doped silicon pillars

This paper presents a new silicon-on-insulator(SOI) lateral-double-diffused metal-oxide-semiconductor transistor(LDMOST) device with alternated high-k dielectric and step doped silicon pillars(HKSD device). Due to the modulation of step doping technology and high-k dielectric on the electric field and doped profile of each zone, the HKSD device shows a greater performance. The analytical models of the potential, electric field, optimal breakdown voltage, and optimal doped profile are derived. The analytical results and the simulated results are basically consistent, which confirms the proposed model suitable for the HKSD device. The potential and electric field modulation mechanism are investigated based on the simulation and analytical models. Furthermore, the influence of the parameters on the breakdown voltage(BV) and specific on-resistance(R_on,sp) are obtained. The results indicate that the HKSD device has a higher BV and lower R_on,sp compared to the SD device and HK device.     

Enhancement of electrochemical performance in lithium-ion battery via tantalum oxide coated nickel-rich cathode materials

Nickel-rich cathode materials are increasingly being applied in commercial lithium-ion batteries to realize higher specific capacity as well as improved energy density. However, low structural stability and rapid capacity decay at high voltage and temperature hinder their rapid large-scale application. Herein, a wet chemical method followed by a post-annealing process is utilized to realize the surface coating of tantalum oxide on LiNi_0.88Mn_0.03Co_0.09O₂, and the electrochemical performance is improved. The modified LiNi_0.88Mn_0.03Co_0.09O₂ displays an initial discharge capacity of ～ 233 mAh/g at 0.1 C and 174 mAh/g at 1 C after 150 cycles in the voltage range of 3.0 V-4.4 V at 45℃, and it also exhibits an enhanced rate capability with 118 mAh/g at 5 C. The excellent performance is due to the introduction of tantalum oxide as a stable and functional layer to protect the surface of LiNi_0.88Mn_0.03Co_0.09O₂, and the surface side reactions and cation mixing are suppressed at the same time without hampering the charge transfer kinetics.     

二氧化铅电极上氧发生反应的交流阻抗研究

测定了二氧化铅电极上氧发生反应的交流阻抗。用曲线拟合法解析组抗谱,求得了反应电阻R_t、吸附电阻R_a、双层电容C_d、吸附电容C_a的值。认为(OH)吸+H₂O→(O)吸+H₃O⁺+e^-是氧发生反应的控制步骤。讨论了C_d、C_a与OH^-离子浓度变化的关系。     

酶联适配体传感器比色检测牛奶中恩诺沙星残留

通过裁剪分析和共聚焦成像鉴定了适配体的结合域,根据结合域位于3'端茎-环的特点,建立了外切核酸酶Ⅰ依赖的酶联核酸适配体比色分析法检测恩诺沙星残留.波长450 nm吸光度与恩诺沙星浓度呈线性关系,方法的线性范围为36～254 μg/L,检测限为15 μg/L.实际试样检测显示:15个牛奶样本里有6个检出恩诺沙星残留,残留...