Facile solvent-free synthesis of pure-phased AlN nanowhiskers at a low temperature

Pure hexagonal aluminum nitride (AlN) nanowhiskers have been successfully synthesized by directly reacting AlCl₃ with NaN₃ in non-solvent system at the low temperature of 450 °C for 24 h. The obtained products are characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy and selected area electron diffraction, which show that the obtained products are hexagonal phase AlN nanowhiskers with width from 10 to 80 nm and length up to several micrometers. The influencing factors of the formation of AlN nanowhiskers were discussed and a possible growth mechanism for AlN nanowhiskers was proposed. Additionally, the study on the corresponding optical properties and catalytic properties is also carried out.     

Ni^2—交换蒙脱石中的镍物种及焙烧温度影响研究

对一组自制Ｎｉ＾２＋交换蒙脱石样品中镍物种的存在在形及焙烧温度影响进行了ＴＰＲ和ＸＲＤ考察结果表明，样品中镍负载量等于或小于Ｎｉ＾２＋的交换量时，镍主要以难还原听可交换性阳离子Ｎｉ（ＯＨ）＾ｑ＋ｘ和易还原的自由态镍Ｎｉ（ＯＨ）２或ＮｉＯ两种形式存在。     

First principles study of small palladium cluster growth and isomerization

Structures and physical properties of small palladium clusters Pd_n up to n = 15 and several selected larger clusters were studied using density functional theory under the generalized gradient approximation. It was found that small Pd_n clusters begin to grow 3‐dimensionally at n = 4 and evolve into symmetric geometric configurations, such as icosahedral and fcc‐like, near n = 15. Several isomers with nearly degenerate average binding energies were found to coexist and the physical properties of these clusters were calculated. For several selected isomers, relatively moderate energy barriers for structural interchange for a given cluster size were found, implying that isomerization could readily occur under ambient conditions. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

超离子导体CaF2中的Ca2+亚晶格和F-亚晶格

CaF_2在熔化以前为超离子导体相。一些实验和理论的研究表明,在超离子导体相中,Ca~(2+)仍维持原有的面心立方骨架,而F~-则在Ca~(2+)骨架中运动。早期的分子动力学模拟结果表明Ca~(2+)的均方根位移仅约0.3A,而F~-的扩散系数可达2.6×10~(-5)cm·s~(-1),已是熔盐扩散系数量级。近年来的中子散射实验表明在扩散离子和近邻离子间存在着某种动力学相关。为解释这些事实,新近Gillan的分子动力学模拟表明扩散离子伴随着F~-亚晶格变形,而Kaneko和Ueda的分子动力学模拟则表明扩散离子伴随着近邻离子在同一运动方向的相关运动。进一步的研究尚待进行。八十年代初,Nelson等人提出了描述晶体、非晶和液态中键取向的键球谐函数方法。     

蜜蜂外激素9－ODA和9－HDA的合成

６－溴－２－己酮在Ｌｉ２ｃｕＣｌ４催化下与γ－溴代巴豆酸甲酯进行格氏偶联，合成了蜂王物质９－羰基－（Ｅ）－２－癸烯酸（９－ＯＤＡ），将其还原得到另一蜂王物质９－羟基－（Ｅ）－２－癸烯酸（９－ＨＤＡ）。该法是合成９－ＯＤＡ和９－ＨＤＡ的新路线。     

Synthesis of 8,9-dialkoxy-substituted tetrahydrobenz[h] isoquinolines

6,7-Dimethoxy-2-naphthylethylamine, prepared by the diborane reduction of 6,7-dimethoxy-2-naphtlialeneacetamide, underwent a Pictet-Spengler cyclization to form 8,9-dimethoxy-1,2,3,4-tetrahydrobenz[h]isoquinoline. This compound is identical with that obtained by reduction of the corresponding dihydrobenzisoquinoline prepared from formamide cyclization. 6,7-Dialkoxy-2-naphthaleneacetic acids, the key intermediates for the preparation of these amides, were obtained from 6,7-dialkoxy-2-acetonaphthones by a modified Willgerodt reaction.     

Microfluidic synthesis of high-valence programmable atom-like nanoparticles for reliable sensing

Synthesis of programmable atom-like nanoparticles (PANs) with high valences and high yields remains a grand challenge. Here, a novel synthetic strategy of microfluidic galvanic displacement (μ-GD) coupled with microfluidic DNA nanoassembly is advanced for synthesis of single-stranded DNA encoder (SSE)-encoded PANs for reliable surface-enhanced Raman scattering (SERS) sensing. Notably, PANs with high valences (e.g., n-valence, n = 12) are synthesized with high yields (e.g., >80%) owing to the effective control of interfacial reactions sequentially occurring in the microfluidic system. On the basis of this, we present the first demonstration of a PAN-based automatic analytical platform, in which sensor construction, sample loading and on-line monitoring are carried out in the microfluidic system, thus guaranteeing reliable quantitative measurement. In the proof-of-concept demonstration, accurate determination of tetracycline (TET) in serum and milk samples with a high recovery close to 100% and a low relative standard deviation (RSD) less than 5.0% is achieved by using this integrated analytical platform.

A novel synthetic strategy is presented for microfluidic preparation of programmable atom-like nanoparticles with high valences and high yields.     

SINGLE AND BINARY ADSORPTION PERFORMANCE OF SALICYLIC ACID AND 5-SULFOSALICYLIC ACID ONTO HYPERCROSSLINKED POLYMERIC ADSORBENTS

Single and binary adsorption behaviors of salicylic acid and 5-sulfosalicylic acid onto hypercrosslinked polymeric adsorbents, i.e. NDA-101 and NDA-99 were investigated. The Freundlich model can successfully describe all the adsorption isotherms tested, which indicates a favorable and exothermic adsorption process. The adsorption of salicylic acid relies on π-π interaction, while the electrostatic interaction further influences the adsorption of 5-sulfosalicylic acid onto NDA-99. The adsorptive capacity of salicylic acid on NDA-99 decreases but increases on NDA-101 with 5-sulfosalicylic acid as the background component in a binary solute system. The amount of 5-sulfosalicylic acid adsorbed was decreased with the increase in initial concentration of salicylic acid on both adsorbents. The competition for the adsorption sites is considered to be predominant in the solid-to-liquid interaction process. The adsorption selectivity of salicylic acid onto NDA-101 is higher than onto NDA-99 by more than an order of magnitude. Thus, combination technique involving NDA-101 followed by NDA-99 can be effectively applied to separate and recover salicylic acid and 5-sulfosalicylic acid from wastewater.     

胶束增溶光度法同时测定铂、铑、钯和金的研究

本文研究了贵金属Pt、Rh、Pd和Au在SnCl_2-BRB-AG-乳化剂OP离子缔合物体系中显色反应的条件,采用偏最小二乘回归法对上述体系重迭光谱进行解析及数据处理。结果表明,该体系灵敏度高,表观摩尔吸光系数可达1.74×10～6～2.47×10～6L·mol～-1·cm～-1;体系稳定性较好。应用本文方法对混合试样中Pt、Rh、Pd、Au进行同时测定,取得较满意的结果。     

Application of a novel micro-injector in the determination of indole derivatives in the rat pineal gland by capillary electrophoresis with electrochemical detection

A novel micro-injector has been fabricated for capillary electrophoresis (CE). It was successfully used for the determination of some indole derivatives for example melatonin (MT), serotonin (5-HT), tryptophan (Trp), and 5-hydroxy-tryptophane (5-HTrp) in the rat pineal gland by capillary electrophoresis with electrochemical detection (CE-EC). CE was performed in 0.20 mol L(-1) phosphate buffer (pH 8.0). The compounds investigated can be well separated and detected within 15 min. The working electrode used was a 300-microm diameter carbon electrode positioned opposite the outlet of the capillary. The relationship between peak current and analyte concentration was highly linear in the range from 0.10 to 500 micromol L(-1); detection limits (S/N = 3) were 0.03-0.13 micromol L(-1). The proposed method has been successfully used to analyze real biological samples.