Thermal behaviour of amorphous Li2ZrO3 prepared by sol-gel technique

The results of the investigations of thermal behaviour of Li₂ZrO₃, prepared in the amorphous state by means of sol-gel technique are demonstrated. The thermal treatment was carried out in air under constant heating rate of 5 deg·min^–1 and cooling rate of 2.5 deg·min^–1. The methods of DTA, TG, Emanation Thermal Analysis (ETA) and dilatometry were used, for characterization of the thermal behaviour in dynamic conditions. The X-ray diffraction patterns were used for characterization of the phase changes observed by TA Methods.

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Zusammenfassung Ergebnisse aus Untersuchungen des thermischen Verhaltens von Li₂ZrO₃, hergestellt mittels einer Sol-Gel-Technik im amorphen Zustand werden dargelegt. Die thermische Behandlung wurde in Luft bei einer konstanten Aufheizgeschwindigkeit von 5 Grad·min^–1 und einer Abkühlgeschwindigkeit von 2,5Grad·min^–1 durchgeführt. Zur Beschreibung des thermischen Verhaltens unter dynamischen Verhältnissen wurden DTA, TG, Emanationsthermoanalyse und Dilatometrie angewendet. Zur näheren Charakterisierung der bei TG beobachteten Phasenumwandlungen wurde Röntgendiffraktion verwendet.

     

Die Kristallstruktur von wasserfreiem Melaminiumchlorid

Crystal Structure of non‐aqueous Melaminium Chloride Melaminium chloride was obtained as colorless, needle‐shaped, single crystalline material from solid state reactions between melamin and ammonium chloride. The structure of [C₃N₆H₇]Cl was refined by single crystal X‐ray diffraction: I2/m, Z = 8, a = 852.87(4), b = 1704.4(1) c = 918.44(4) pm and β = 92.165(6)°. The crystal structure contains melaminium ions stacked to columns along [100] and linked via N‐H···N bridges to form bands along [001]. Both of the two distinct chloride ions are stabilized by six hydrogen bonds through distorted trigonal prismatic arrangements of hydrogen atoms to yield a supramolecular structure.     

利用LB技术以寡聚DNA为模板构建CdS纳米结构

利用Langmuir-Blodgett技术制备了十八胺（ODA）／十聚腺嘌呤（oligo-A10)单分子膜，并以其为模板制备了不同形状的Cds纳米结构，结果表明以在低膜压下转移的寡聚DNA单层为模板可诱导生成线形的Cds纳米结构，而以在主膜压下转换的寡聚DNA单层膜板得到的是Cds的球形结构聚集体。     

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。     

Quality assurance system for a decomposition method as demonstrated for the Wickbold combustion technique

 A five-step model for a quality assurance system is developed for an internal quality control check. It includes the quality control of the decomposition method and the detection method as steps belonging together. The Wickbold combustion technique as decomposition method in combination with atomic absorption spectrometry was chosen. The vaporization of the elements mercury, arsenic, lead, antimony and selenium is based on combustion in an oxyhydrogen flame. To check the efficiency of the analytical system, the uncertainty of results was calculated on the basis of the "Guide to the Expression of Uncertainty in Measurement". Received: 13 January 1997 · Accepted: 29 March 1997     

Efficient synthesis of isoflavone analogues via a Suzuki coupling reaction

Analogues of 3-aryl-8-isobutyl-5,6,7-trihydroxy-2-methyl-4H-chromen-4-one were synthesized with high yields via the Suzuki coupling reaction of 3-iodo-8-isobutyl-5,6,7-trimethoxy-2-methyl-4H-chromen-4-one with different aryl boronic acids.     

3,4—亚甲二氧基苯甲酸锡酯的合成及表征

３，４－亚甲二氧基苯甲酸及其取代物与三苯基氢氧化锡或二丁基化锡反应合成了５个锡酯，通过元素分析，ＩＲ和＾１ＨＮＭＲ对其进行了表征。     

1─芳氧基乙酰基─4─苯甲酰氨基硫脲衍生物的合成及其生物活性研究

１─芳氧基乙酰基─４─苯甲酰氨基硫脲衍生物的合成及其生物活性研究魏太保，陈继畴（西北师范大学化学系，兰州，７３００７０）杨素铀，王秀春（西北师范大学生物系，兰州，７３００７０）关键词：１—芳氧基乙酰基—４—苯甲酰基氨基硫脲，相转移催化，合成，生物活性...     

Deux methodes photothermiques a l'etude d'une preparation de contact d'un melange binaire de cristaux liquides

The photopyroelectric (PPE) method is proposed as a sensitive technique to study a binary mixture of liquid crystals in a contact preparation. The photothermal signal is generated while scanning the contact preparation. The crystal-smectic A, smectic A-nematic, and nematic-isotropic interphase boundaries are detected. The displacement of these boundaries due to the variation of the temperature is monitored. The study of these displacements allows us to draw the complete temperature-concentration phase diagram of a binary mixtures. This revised version was published online in August 2006 with corrections to the Cover Date.