Algebras of quotients of graded Lie algebras

In this paper we explore graded algebras of quotients of Lie algebras with special emphasis on the 3-graded case and answer some natural questions concerning its relation to maximal Jordan systems of quotients.     

商代墓向的统计分析

本文采用系统聚类分析等方法 ,对河南、河北两省部分地域内发掘出的商代墓葬的方向进行统计分析发现 ,商代墓葬具有非常明显的埋葬规律性。并判断出这部分地域内商代墓葬的墓主人至少可归属于 1 3个主要族属。此结论恰好与《左传》定公四年记载的分鲁公和分康叔殷族属数之和相一致。     

Synthesis and antiviral evaluation of several 6-(Methylene-carbomethoxy)pteridine-4,7(3H,8H)-diones

The reactions of 5,6-diaminopyrimidin-4(3H)-one derivatives 1a-h , with dimethyl acetylenedicarboxylate are discussed in this paper. 6-Amino-5-(E)(1′,2′-dicarbomethoxyvinyl)aminopyrimidines, 2 , and 6-(methylenecarbomethoxy)pteridinones, 3 , have been obtained as main the products, which can be explained on the basis of a Michael addition on pyrimidine derivatives, and cyclization. Those compounds were evaluated for their in vitro antiviral activity.     

一种启发式能量优化的无线传感器网络数据收集算法

建立了基于能耗和剩余能量约束的无线传感器网络数据收集模型.提出了一种新的基于目标偏差度函数的启发式算法,该算法根据前次计算的结果和约束要求以及自适应动态调整目标函数加权系数的取值,避免了无效重复计算,使算法始终朝着有效的方向搜索.仿真分析表明本算法在网络存活时间指标上优于最小能耗算法;在算法的时间复杂度和搜索成功率上优于k-Dijkstra算法.     

Automatic chemiluminescence-based determination of carbaryl in various types of matrices

Carbaryl, a modern pesticide widely used for both agricultural and non-agricultural purposes, was determined from the chemiluminescence produced in its reaction with Ce(IV) in a nitric acid medium containing rhodamine 6G as sensitizer, using flow-injection techniques. A straightforward automatic method based on measurements peak height and peak area, which are directly proportional to the carbaryl concentration, was thus developed. Calibration graphs are linear over the concentration range from 50 to 2000 ng mL⁻¹. The limit of detection, as determined according to Clayton, is 45.6 and 28.7 ng mL⁻¹ for peak height and peak area measurements, respectively. The relative standard deviation for 10 samples was less than 1.4% with both types of measurements. Two commercial formulations containing carbaryl were analysed using both types of measurements, which provided acceptable recovery values. Solid-phase extraction was used to concentrate and separate the analyte from the matrix. The method was successfully applied to the analysis of spiked water samples as well as in soil and grain samples. The proposed method exhibited a high selectivity no other pesticide containing the naphthalene group such as antu, napropamide or naftalam, etc., was found to interfere with the determination of carbaryl.     

Formation of low-temperature cirrus from H2SO4/H2O aerosol droplets

We present experimental results obtained with a differential scanning calorimeter (DSC) that indicate the small ice particles in low-temperature cirrus clouds are not completely solid but rather coated with an unfrozen H2SO4/H2O overlayer. Our results provide a new look on the formation, development, and microphysical properties of low-temperature cirrus clouds.     

Regioselective synthesis of novel N2- and N4-substituted 7-methylpyrazolo[4,5-e][1,2,4]thiadiazines

The new compound 7-methylpyrazolo[4,5-e][1,2,4]thiadiazin-3(2H,4H)-one1,1-dioxide (5) was synthesized and its novel mono N2- or N4-substituted derivatives 6 and 7 were prepared by regioselective N-alkylation of 5 with different molar ratios of NaH and alkyl halides. Based on the regioselective alkylation conditions found a facile one-pot synthesis of N2,N4-disubstituted pyrazolo[4,5-e][1,2,4] thiadiazines 8 was developed. The structures of the newly synthesized compounds were confirmed by IR,(1)H-NMR, (13)C-NMR and MS spectral analysis.     

Determination of pesticides in washing waters of olive processing by gas chromatography-tandem mass spectrometry

A simple and rapid SPE-GC method for the determination of 30 organochlorine, organophosphorus, and organonitrogen pesticides at ng/L levels in washing water of olive processing has been developed. Twenty-nine samples of water were collected directly in the inlet and outlet of the washing machines of three olive mills at various locations in Spain. Preconcentration and clean-up were performed by elution of the pesticides from a C18 SPE cartridge using dichloromethane. The target compounds were determined in the final extract by GC-MS/MS. The most frequently encountered pesticide residues were terbuthylazine, simazine, and diuron. In some of the water samples, coming from the inlet of the washing machines, terbuthylazine and diuron concentrations were above the maximum residue limit.     

Wetting properties of polystyrene/divinylbenzene crosslinked porous polymers obtained using W/O highly concentrated emulsions as templates

Macroporous polystyrene/divinylbenzene (PS‐DVB) monoliths were obtained using highly concentrated W/O emulsions as templates. These monoliths are of interest due to the high potential applications for catalysis, scaffolds for tissue engineering, filters, membranes, or drug delivery systems. Dynamic wetting behavior through the polymer monolith is directly related to contact angle. For this reason, in this paper we investigate the relationship between contact angle, morphology, and chemical composition of the dense skin layer and the highly porous interior surface of PS‐DVB porous monoliths. Whereas the dense skin layer exhibits a Wenzel regime using water as wetting liquid, the highly porous interior surface exhibits a Cassie–Baxter regime. This behavior is correlated with the roughness observed by scanning electron microscopy (SEM). However, the observed contact angle hysteresis seems to indicate that factors other than surface roughness should be taken into account. For this reason, chemical composition was also studied by elemental microanalysis and X‐ray photoelectron spectroscopy (XPS). The differences in chemical composition observed between the dense skin layer and the highly porous interior surface, according to the wetting model for a heterogeneous surface proposed by Johnson and Dettre, seems also to contribute to the wetting hysteresis. The different wetting between the dense skin layer and the highly porous interior surface results in a dual wettability phenomenon, in which a liquid wets the dense skin layer and does not penetrate into the highly porous interior of the PS‐DVB monoliths. This phenomenon can be of relevance in absorption or desorption processes such as in drug delivery processes. Copyright © 2009 John Wiley & Sons, Ltd.