高效率变色WO3多聚体/1，10-DAD自组装薄膜的制备

A novel high-efficient photochromic self-assembly multilayered film has been fabricated from WO3 and 1,10-DAD solution using molecular deposition technique.The dependence of photochromic behavior on with WO3 in the WO3-polymer/1,10-DAD self-assembly film was discussed in comparison with WO3/4,4-BAMBp system.The results clearly show that organic molecules determine the charge density of the photo-induced charge-tracsfer complexes,andthus manipu-late the structure and the photochromic properties of the films.     

High strength elastic polypropylene

The transformation of a spun isotactic polypropylene fiber into a high strength elastic fiber has been followed structurally. By examining each stage of the transformation separately, it has been possible to identify the different structural mechanisms that occur as the process proceeds. The recognition of the important role the noncrystalline polymer plays in the process is a particularly significant result of the study.     

High resolution millimeter-wave spectroscopy of cyclopropylphosphine-borane

The microwave spectrum of cyclopropylphosphine-borane, C(3)H(5)PH(2)-BH(3), has been investigated in the frequency range 150-195 GHz. The spectral assignment was supported by high level ab initio calculations. Two stable conformations have been predicted: the most stable antiperiplanar form and synclinal form that is higher in energy by 7.3 kJ/mol. In the observed spectra, only the most stable antiperiplanar (ap) form has been assigned. The analysis of the rotational spectra in the lowest excited vibrational states of the ap conformer has enabled determination of the potential function for the C-P torsional mode in the vicinity of equilibrium position. The barrier to internal rotation of the BH(3) top has been determined to be 9.616(15) kJ/mol and agrees well with quantum chemical calculations.     

高温高压下翡翠宝石的人工合成

翡翠(NaAlSi₂O₆)是一种具有较高硬度和较大韧性的矿物质。Loring等人从1948年开始研究翡翠的人工合成,直至1984年底美国G.E.公司才报道高温高压下合成宝石级翡翠成功,但没有详细的工艺说明。本工作仔细探索了宝石级翡翠的合成工艺,研究了压力和温度对翡翠合成的影响和不同离子的掺杂及掺杂浓度对翡翠颜色的影响。     

单相Ce0.5Zr0.5O2立方固溶体的高压高温合成

以化学沉淀法制备的 Ce O2 和 Zr O2 纳米微粒为前驱体 ,首次在高压高温 (3 .1 GPa,1 0 73 K)下合成了单相 Ce0 .5Zr0 .5O2 面心立方固溶体 .使用 X射线衍射、TG-DTA、XPS、Raman、电子自旋共振谱和交流阻抗谱等对样品的结构、Ce离子的价态和导电性进行了表征 .实验结果表明 ,纳米 Ce O2 -50 % Zr O2 混合物在高压 (0 .9GPa以上 )高温 (1 0 73 K以上 )条件下可以发生固态反应 ,高压下固溶温度明显降低 .Ce0 .5Zr0 .5O2 面心立方固溶体在 773 K以下是热稳定的 ,不发生结构转变 ,固溶体中 Ce离子完全以 Ce4 + 形式存在 ,773 K退火也不引起 Ce4 + 向 Ce3 + 转变 ,晶格中氧缺位非常少 .Ce0 .5Zr0 .5O2 面心立方固溶体是离子导电 ,82 3 K时电导率 σ=1 .2× 1 0 -5S/cm,与纯 Ce O2 在同温度下的电导率同数量级 ;1 1 2 3 K时 σ=2 .1× 1 0 -3 S/cm,小于掺入稀土或碱土氧化物的氧化锆和氧化铈基电解质的电导率 .在高温区和低温区 ln(σT)与 1 /T的关系满足斜率不同的二条直线 ,低温活化能小于高温活化能 .固溶体的显微硬度 (50 g载荷 )为 572 HV.     

Bell-Vol High Volume Sampler

Abstract

Maintenance of a constant flow rate has been a long-standing problem with hi-vol samplers used to collect ambient aerosol. Numerous types of commercially available flow controllers are currently in use. A passive flow controller has now been developed that operates without external power or electrical circuits, and, when coupled with an AC inductive motor and cyclone blower, effectively controls flow rate between 100 and 1500 L/min.

The flow controller described here controls mass flow rate rather than motor speed - the method used in commercially available hot wire anemometer electronic flow controllers - by continuously applying pressure to the outlet air stream. Thus, the controller is unaffected by such problems as brush wear and line voltage variations that are common to hi-vol samplers. In operation, the pressure drop across any constant flow resistance, such as an orifice, elbow, or length of tubing in conjunction with a diaphragm, functions as a servo mechanism to maintain a constant drop across this constant resistance.     

High pressure-high temperature phase diagram of ammonia

The high pressure (P)-high temperature (T) phase diagram of solid ammonia has been investigated using diamond anvil cell and resistive heating techniques. The III-IV transition line has been determined up to 20 GPa and 500 K both on compression and decompression paths. No discontinuity is observed at the expected location for the III-IV-V triple point. The melting line has been determined by visual observations of the fluid-solid equilibrium up to 9 GPa and 900 K. The experimental data are well fitted by a Simon-Glatzel equation in the covered P-T range. These transition lines and their extrapolations are compared to the reported ab initio calculations.     

Effect of High Humidity Exposure to Wheat Starch Based High Conducting Flexible Polymer-in-Salt-Electrolyte

Polymer-in-salt-electrolytes (PISEs) are an important class of electrolytes as they carry the promise of faster and single ion transport. Unfortunately, due to unavailability of a suitable polymer host PISE has still not reached to commercial level. In the present work, using a novel synthesis protocol developed by the group, glutaraldehyde crosslinked wheat starch has been successfully modified with sodium iodide (NaI) to synthesize a flexible PISE membrane with desired electrochemical properties. Present paper reports the effect of crosslinker and exposure to high humidity ambience on electrochemical and morphological properties. It has been established that on exposure to higher humidity atmosphere starch-based PISEs stabilize at lower resistance value, but with higher ion relaxation time, which indicates that effect of high humidity treatment is more on salt dissociation instead of assisting the ion transport. The studied materials have conductivity ≈0.01 S cm⁻¹ range with ESW >2.5 V, ensuring its usability in electrochemical devices. The developed synthesis protocol does not require any complicated synthesis route and/or sophisticated instrument hence the overall process is economical also, adding up to its potentiality for energy device fabrication.     

Electrokinetic Measurements at High Electrolyte Concentrations

The method of capillary electrokinetics has for the first time been used to measure streaming current at high electrolyte concentrations. It has been shown that the streaming current is proportional to the applied pressure. At an electrolyte concentration of 1 M, the thickness of the diffuse layer is comparable with the size of a water molecule (0.3 nm); i.e., there is almost no diffuse layer. The existence of the streaming current in this case indicates that there are no hydrodynamically immobile layers near a smooth solid surface.     

High resolution millimeter-wave spectroscopy of vinyltellurol

The millimeter-wave rotational spectrum of vinyltellurol has been recorded and assigned for the first time. To support the spectrum assignment, high level ab initio calculations have been carried out. Geometries, total electronic energies, and harmonic vibrational frequencies have been determined at the MP2 level. A small-core relativistic pseudopotential basis set (cc-pVTZ-PP) was employed to describe the tellurium atom. Two stable conformers, synperiplanar (sp) and anticlinal (ac), have been identified. The sp conformer is planar with a small negative inertia defect of -0.025 u ?(2). The ac conformer was found to be nonplanar with a C-C-Te-H dihedral angle of about 140° from sp. This conformer exhibits a large amplitude motion associated with the torsion about the C-Te bond. The barrier to internal rotation is about 1 kJ/mol, according to the theoretical calculations. For the ac conformation, a torsional potential function consisting of quartic and quadratic terms of the torsional angle has been partially determined from the observed rotational constants.     

High resolution LAPS and SPIM

The resolution of photocurrent measurements at field-effect capacitors as used in light-addressable potentiometric sensors (LAPS) and scanning photo-induced impedance microscopy (SPIM) has been investigated using silicon on sapphire (SOS) substrates illuminated at different wavelengths. Using a two-photon effect in silicon (λ = 1250 nm) to generate the photocurrent, genuine submicrometer resolution has been demonstrated for LAPS and SPIM. Improved sensitivity for both LAPS and SPIM was obtained using a 6.7 nm thick gate oxide on SOS anodically grown in 0.1 M HCl.     

Preparation of Silver Nanofluids with High Electrical Conductivity

Silver nanofluids have been prepared by single-step chemical reduction method starting with silver nitrate metal precursor. Electrical conductivity of nanofluids has been investigated, as it has largely been overlooked despite immense technological importance. Extremely low yield nanofluid (0.013 wt%) is found to give high electrical conductivity attributed to smaller size monodisperse nanoparticles obtained (16.3 nm). Increased precursor concentration has lead to high yield and high electrical conductivity. Larger particle sizes obtained are optimized by reducing the yield at high concentration, as well as by dilution. The stability is exceptionally higher than the reported results for copper nanofluids.     

High Temperature Stability of Sol-Gel-Derived SiOC Glasses

The high temperature stability of sol-gel-derived SiOC glasses has been investigated in order to understand the role played by the presence of a free-carbon phase in the amorphous oxycarbide network. Therefore, pure and excess free-carbon containing SiOC glasses have been prepared from hybrid gels and used for the high temperature stability experiments. Moreover, the possible effects of the sample size with respect to local kinetics and thermodynamics and of the testing environment have also been investigated. Results show that all these parameters play a crucial role in defining the high temperature behavior of SiOC glasses.     

Solvent-Free Mechanochemical Synthesis of High Transition Biphenyltetracarboxydiimide Liquid Crystals

A series of high temperature alkyl and alkoxy biphenyltetracarboxydiimide liquid crystals have been prepared under ball mill method using solvent-free mechanochemical approach. The thermal properties of the prepared compounds were investigated by deferential scanning calorimetry (DSC) measurements and the textures were identified by polarized optical microscope (POM). The compounds showed smectic mesomorphic behaviour. The results showed the increasing nature of transition temperature Cr-SmC with chain length with increments of the SmC mesophase range. However, the mesophase range of the SmA was decreased with the terminal chain length either for the alkyl or alkoxy terminal groups. Moreover, the DFT theoretical calculations have been conducted give a detailed projection of the structure of the prepared compounds. A conformational investigation of the biphenyl part has been studied. A deep illustration of the experimental mesomorphic behaviour has been discussed in terms of the calculated aspect ratio. A projection of the frontier molecular orbitals as well as molecular electrostatic potential has been studied to show the effect of the polarity of the terminal chains on the level and the gap of the FMOs and the distribution of electrostatic charges on the prepared molecules.     

高效液相色谱技术在代谢组学研究中的应用

高效液相色谱技术逐渐广泛应用于代谢组学的研究中。迄今为止,该技术已经在不同生理状态的生物体液的代谢指纹谱分析中得到了应用。本文评述了传统高效液相色谱技术、毛细管技术和超高效液相色谱等技术在代谢组学的应用。     

The Stripping Voltammetry In High Frequency Electromagnetic Field

The effectiveness of high frequency electromagnetic field influence on the analytical signal value in the stripping voltammetry method depending on such factors as the nature and concentration of the defined element, nature and concentration of the supporting electrolyte and agitation velocity has been studied. It has been demonstrated that an analytical signal increase may be achieved that allows one to lower a detection limit and to reduce the time of individual definition. The highest peak current is observed at some definite frequencies of the exterior field depending on the nature of the element and on the supporting electrolyte as well.     

High throughput screening in agrochemical research

The demand for new herbicides, insecticides and fungicides led to a steady increase in the number of compounds being tested to find novel market products. To keep pace with the rising workload, high throughput screening (HTS) technologies have been introduced. In agrochemical research miniaturised in vivo tests on whole real target organisms are now possible and are an integral part of the screening cascade. A complementary target based in vitro HTS has also been established in agrochemical research. Target based HTS allows a directed approach towards untouched market shares by novel modes of action. Selection of the best suited targets is the most crucial issue in this approach. Genomic methods thereby deliver many essential genes as candidate targets. Consideration of further criteria such as druggability notably narrows down the number of promising targets. Though target to hit to lead progression still is as in pharmaceutical research a complex and therefore risky process, the implementation of novel bioscience technologies has entailed the transition to an integrated innovative agrochemical research perspective.     

High temperature structures and orientational disorder in compressed solid nitrogen

An experimental study of the phase transitions at high temperature in compressed solid nitrogen has been performed using Raman spectroscopy. Knowledge of the equilibrium phase diagram in the region of the ordered epsilon phase and the two disordered delta and deltaloc phases, at pressures between 10 and 20 GPa, has been extended up to 500 K. The Raman scattering line shape and line width of the active vibrons has been measured accurately, along isobaric scans, across the phase transitions. Analysis of the width and of its different behavior with increasing temperature in the three phases led to more precise conclusions about the nature of the disorder in the different phases. Observation of an evident shoulder in the nu2 band of the deltaloc phase suggests the possibility that sites of two different symmetries may be occupied by the disk molecules in this structure.     

High pressure sorption isotherms via differential pressure measurements

A differential pressure adsorption unit (DPAU) has been constructed which is capable of accurately measuring isotherm data up to 2000 psia with as little as 100 mg of sample. This non-traditional adsorption/desorption method has been benchmarked by comparing hydrogen and methane isotherms measured with standard volumetric and gravimetric instruments on a NaA (4A) zeolite and an activated carbon at near ambient temperatures. The results from stability tests and well as the details of the mathematical analysis for this differential pressure method are also provided.     

High precision NMR study of 1,1-disubstituted silacyclobutanes

The hydrogen NMR spectra of 1,1-dimethyl-, 1,1-dichloro-, 1,1-dimethoxy- and 1,1-difluoro-silacyclobutane have been analysed. A new correlation NMR instrumental technique has been used to obtain spectral parameters with very high precision.