Infrared spectroscopic characterization of the buried interface and surfaces of bonded silicon wafers

Basic investigations have been carried out on the characterization of different processing steps in bond preparation using etched <111> faces of silicon wafers for the incidence of the infrared beam to a multiple internal reflection geometry. The method is very sensitive to the surface coverage and interface. Surface activation by RCA cleaning yields an increase of water coverage and a decrease of SiH and CH groups. The detection limit for an oxide layer between silicon wafers has been found to be about 3 nm. Received: 18 July 1997 / Revised: 15 August 1997 / Accepted: 19 August 1997     

Separation of Sulfonylurea Herbicides and Determination of Bensulfuron-methyl Residues in Tapwater by HPTLC

JPC – Journal of Planar Chromatography – Modern TLC - In this work we have studied the separation of a mixture of the sulfonylurea herbicides (metsulfuron-methyl, chlorsulfuron,...     

有序自组装聚合物纳米结构

采用水辅助方法(water-assisted fabrication method),分别以4-十二烷基苯磺酸掺杂的聚苯胺(PANI-DBSA)和聚2-甲氧基-5-(2′-乙烯基-己氧基)苯乙炔(MEH-PPV)两种功能高聚物为成膜材料,冷凝水滴为模板,利用水滴在聚合物溶液表面的自组装,制备出了两种纳米层次以上的蜂窝状有序多孔聚合物薄膜.通过原子力显微镜和共聚焦荧光显微镜对其形貌、电学性质和荧光图像进行了表征.     

反相高效液相色谱法测定3种中成药中的葛根素

 建立了测定小儿清感灵片、步长新脑心通胶囊和感冒清热颗粒 3种中成药中葛根素含量的反相高效液相色谱方法。采用APEXODS色谱柱 ,以醋酸铵缓冲液 (10 0mmol/L ,pH 5 0 ) 甲醇 (体积比为 75∶2 5 )的混合溶液为流动相 ,检测波长为 2 5 0nm ,流速为 0 8mL/min。葛根素在 2mg/L～ 2 0mg/L时其色谱峰面积与质量浓度的线性关系良好 (r =0 9999) ;上述 3种中成药中的葛根素含量分别为 3 48mg/g ,1 0 8mg/ g及 1 5 2mg/ g(蔗糖型 ) ;其加样回收率分别为 99 0 % ,93 4%和 97 5 %。该法简便、快速、专属性强 ,可以作为多种中药制剂中葛根素含量的测定方法。     

Semipreparative separation and determination of eleutheroside E in Acanthopanax giraldii Harms by high-performance liquid chromatography

A method for the isolation, purification, and determination of eleutheroside E in Acanthopanax giraldii Harms, collected in the Sichuan province (China), is established. The water extraction of A. giraldii Harms is pre-isolated using macroporous adsorption resin (D-101) and a C18 solid-phase extraction cartridge, and the enriched extract is purified to give eleutheroside E (syringaresinol-di-O-beta-D-glucoside; liriodendrin) by semipreparative reversed-phase high-performance liquid chromatography. Structure identification is performed by a comparison of IR, 1H-NMR, 13C-NMR, and electrospray ionization-mass spectrometric data with the literature. The final purity of the compound is 97%. Quantitative determination of eleutheroside E in A. giraldii Harms is performed on a Zorbax SB C18 (150- x 4.6-mm i.d., 5 microm) column. The linear range of eleutheroside E is 4.85-194 mg/L (r = 0.9998), and the average recovery is 99.6-101%. The developed method is simple, reproducible, and easy to operate. It is useful for the evaluation of Acanthopanax giraldii Harms.     

A DFT study of the generation of interstellar species XN (X = Cl, and Br) activated by molecular sieve clusters

A cluster DFT (B3LYP) calculation study of ClN₃ and BrN₃ dissociation pathways catalyzed by molecular sieve is reported. A three-tetrahedral molecular sieve cluster (Al(OHSiH₃)(OSiH₃)(OH)₂, called T3) has been chosen in this study. Triplet-state products ClN and BrN are more easily produced with T3 molecular sieve cluster. Although the potential energy surfaces with T3 molecular sieve cluster are similar with those without T3 molecular sieve cluster, the dissociation process of ClN₃ and BrN₃ with T3 molecular sieve cluster becomes easier, which can be attributed to smaller energy gaps from the ground state reactant to the intersystem crossing point.     

SciFinder-guided rational design of fluorescent carbon dots for ratiometric monitoring intracellular pH fluctuations under heat shock

Intracellular pH plays a significant role in various biological processes, including cell proliferation, apoptosis, metabolism, enzyme activity and homeostasis. In this work, a novel design strategy for the preparation of pH responsive carbon dots (CDs-pH) for ratiometric intracellular imaging was reported. By using SciFinder database, fluorescent CDs-pH with the required pK_a value of 6.84 were rationally designed, which is vital important for precise sensing of intracellular pH. As a result, the synthesized CDs-pH demonstrated robust ability to test pH fluctuations within the physiological range of 5.4-7.4. The CDs-pH was further utilized for fluorescent ratiometric imaging of pH in living HeLa cells, effectively avoided the influence of autofluorescence from native cellular species. Moreover, real-time monitoring of intracellular pH fluctuation under heat shock was successfully realized. This SciFinder-guided design strategy is simple and flexible, which has a great potential to be used for the development of other types of CDs for various applications.     

用峰鉴别技术反相高效液相色谱法测定火锅汤料中微量吗啡

本文报道了以峰鉴别技术为定性依据的测定火锅汤料中微量吗啡的反相高效液相色谱法。本法采用改良的Ｓｔａｓ－ｏｔｔｏ法分离提取复杂样品中的微量吗啡。由于采用峰鉴别技术，增加了定性参数，大大提高了定性方法的准确性。本法简便、快速。最低检出浓度为０．０４ｍｇ／Ｌ。在数十例样品分析中，与其它仪器分析结果比照，非常符合。     

肌苷的离子交换法提取工艺研究

研究了肌苷发酵液不同pH值、树脂预平衡条件、饱和树脂的洗菌、淋洗条件对肌苷离子交换提取和解吸工艺影响情况，并对其离子交换吸附机理进行了详细探讨，旨在确定最佳提取工艺条件。     

基于核酸探针的光学传感方法和细胞成像研究

许多疾病的特征在于各种生物分子表现出的异常活性,这些物质通常在细胞内外显示过表达现象,因此对其灵敏靶向识别可以提供诊断和治疗效用。由于基因诊疗和化学传感技术的发展,用于灵敏检测细胞内外生物化学物质的核酸探针突显优势。核酸探针可以在稳定进入细胞的同时,特异性地结合目标物质,通过光学方法检测或通过成像技术标识出来。本文综述了采用光学传感方法和成像技术,基于核酸探针检测生物分子的新进展。根据检测对象进行分类,概括分析了几个代表性体系:核酸序列、蛋白质和酶、化学物质和物理化学条件,并详细阐述其关键设计原理、灵敏度及样品检测等结果,同时指出了各类核酸探针的优缺点。