Synthesis of Highly Luminescent LnMOFs through Structural Regulation

Two series of three dimensional（3D） lanthanide metal-organic frameworks（LnMOFs） of [Ln（tftpa）_1.5（phen）(H₂O)]_n（Ln = Sm 1a, Eu 1b, Tb 1c, Dy 1d, H2tftpa = tetrafluoroterephthalic acid, phen = 1,10-phenanthrolin） and [Ln（tftpa）1.5（bpy）(H₂O)]_n（Ln = Sm 2a, Eu 2b, Tb 2c, Dy 2d, bpy = 2,2’-bipyridine） are obtained by structural regulation. Results reveal that the 3D LnMOFs show high water-and thermal-stability. Interestingly, through selecting the ...     

Effect of Processing and Aging on Particle Size of Explosives

Influence of such processes as molding powder production, pel-lets pressing and aging under different condit/ons on particle size of TATB ( 1,3,S-trlamino-2,4,6-trinltrobenzene ) and HMX (cyclotetramethylenetetranitramine) was experimentally studied. The results showed that parflele size of these explosives was greatly changed before and airier moldinu powder produc-tion, but for different size grade of explosive this change was not the same; pressing process had also great effect on explosive particle size, but before and after ageing process explosive par-tide size did not change seriously.     

2-(二硝基亚甲基)-4,5-咪唑烷二酮与甲醇的反应研究

以2-甲基咪唑为原料合成2-(二硝基亚甲基)-4,5-咪唑烷二酮(1), 收率为33.9% (16.8%文献值), 首次采用低碳液态醇实现1的开环反应, 产物为FOX-7. 对反应条件进行了优化, 对比了甲醇、甲酸、氨水三种亲核试剂的开环效果, 开环试剂为甲醇时, FOX-7收率为94.6%, 高于文献值(87.4%). 研究了1的络合性能, 合成了1的甲醇加合物2并进行了结构表征. 对开环反应机理和乙二酰脲的形成机理进行了探讨.     

Modular degeneracy of vacuum zero potential point and gauge transformations

This paper presents an extended gauge theory which can contain the Higgs mechanism, considering ⁴ field theory as an example. It can introduce interaction into different vacuum modular degeneracy states and break modular degeneracy. At the same time we can obtain both massless and massive vector bosons. According to the extended gauge theory, gauge transformations can be classified into two kinds: those with fixed parameter, called simply definite gauge transformations, which have a function of breaking modular degeneracy, and indefinite gauge transformations, which have a function of keeping phase degeneracy.     

Determination of nine active components in Radix Hedysari and Radix Astragali using capillary HPLC with diode array detection and MS detection

A capillary HPLC (cHPLC) coupled with diode array detection (DAD) and MS method was developed for the simultaneously qualitative and quantitative determination of nine components, namely vanillic acid, calycosin-7-O-beta-D-glucoside, (6alphaR,11alphaR)-9,10-dimethoxypterocarpan-3-O-beta-D-glucoside, ononin, calycosin, (3R)-2'-hydroxy-3',4'-dimethoxyisoflavan-7-O-beta-D-glucoside, isoliquiritigenin, formononetin, (3R)-8,2'-dihydroxy-7,4'-dimethoxyisoflavan, in Radix Hedysari (Hongqi) and Radix Astragali (Huangqi). Simultaneous separation of these nine compounds was achieved on a Zorbax C18 microcolumn (5 microm, 150 x 0.3 mm). The mobile phase consisted of (A) 0.3% aqueous formic acid and (B) ACN with a gradient elution. The identification of nine compounds in both Hongqi and Huangqi was confirmed by TOF-MS. All calibration curves showed good linearity (R(2) >0.998) within test ranges. This method showed good repeatability for the quantification of these nine components in Hongqi and Huangqi with intra- and inter-day variations of less than 1.89 and 3.13%, respectively. The validated method was successfully applied to quantify nine investigated components in eighteen samples of Hongqi and Huangqi. Hierarchical cluster analysis of 18 samples was performed using the peak area of nine analytes on cHPLC chromatograms. The result showed that Hongqi and Huangqi are significantly different, though the two species of Astragalus are very similar.     

Influence of Schottky drain contacts on the strained AlGaN barrier layer of AlGaN/AlN/GaN heterostructure field-effect transistors

Rectangular Schottky drain AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) with different gate contact areas and conventional AlGaN/AlN/GaN HFETs as control were both fabricated with same size. It was found there is a significant difference between Schottky drain AlGaN/AlN/GaN HFETs and the control group both in drain series resistance and in two-dimensional electron gas (2DEG) electron mobility in the gate-drain channel. We attribute this to the different influence of Ohmic drain contacts and Schottky drain contacts on the strained AlGaN barrier layer. For conventional AlGaN/AlN/GaN HFETs, annealing drain Ohmic contacts gives rise to a strain variation in the AlGaN barrier layer between the gate contacts and the drain contacts, and results in strong polarization Coulomb field scattering in this region. In Schottky drain AlGaN/AlN/GaN HFETs, the strain in the AlGaN barrier layer is distributed more regularly.     

紫外高级还原技术还原降解水中N-亚硝基二甲胺

采用2种高级还原技术(UV/Na2SO3和UV/Na2S2O4)还原降解N-亚硝基二甲胺(NDMA),考察pH值、光照强度、还原剂质量浓度和溶解氧等因素对NDMA还原降解效果的影响,计算还原降解反应过程中的表观反应动力学常数,推断NDMA的还原降解机理.研究结果表明,弱酸性条件下有利于2种高级还原技术对NDMA的还原降...     

Determination of the series resistance under the Schottky contacts of AlGaN/AlN/GaN Schottky barrier diodes

Rectangular AlGaN/AlN/GaN heterostructure field-effect transistors (HFETs) were fabricated,and the gate and the source of the HFETs consisted of AlGaN/AlN/GaN Schottky barrier diodes (SBDs).Based on the measured forward current-voltage and the capacitance-voltage characteristics of the AlGaN/AlN/GaN SBDs,the series resistance under the Schottky contacts (RS) was calculated using the method of power consumption,which has been proved to be valid.Finally,the method of power consumption for calculating R S was successfully used to study the two-dimensional electron gas electron mobility for a series of circular AlGaN/AlN/GaN SBDs.It is shown that the series resistance under the Schottky contacts cannot be neglected and is important for analysing and characterizing the AlGaN/AlN/GaN SBDs and the AlGaN/AlN/GaN HFETs.     

激光拉曼光谱内标法测定红辣椒表面的农残甲基毒死蜱

利用激光拉曼光谱对蔬菜红辣椒表面的农药甲基毒死蜱模拟残留进行了测定,选择红辣椒中富含的β-胡萝卜素的1444.0cm^-1作为内标信号,与农药甲基毒死蜱本身的649.4cm^-1特征拉曼光谱组成相对光谱强度,结果表明相对光谱强度与农药甲基毒死蜱残留量有着很好的线性关系,其线性关系为R=0.143V+2.023,线性相关系数为0.9895。研究表明利用激光拉曼光谱内标法在特定条件下可用于农药残留的测定。