一种复制透射光栅的新方法

利用高折射率的塑料树脂来复制透射光栅的基本原理是:利用有机溶剂溶解塑料树脂,将溶液倒在光栅表面上并推平,待溶液挥发后,光栅表面上就只剩下一层塑料树脂,脱模后即可得到一块光栅常数相同的平面透射光栅,其主要的优点在于:

超高速摄影用高强度铝合金转镜动态特性的研究

转镜型超高速摄影机的信息容量取决于转镜的材料和横截面形状 .本文首次对超高速摄影用高强度铝合金转镜从理论和实验两个方面进行了系统研究 .研究表明 :高强度铝合金是超高速分幅摄影机转镜的理想材料 ;当铝转镜截面形状为正三角形、镜面尺寸为 (1 7× 3 2 .5 ) mm2时 ,转速已达 (5 0× 1 0 4 ) rpm,镜面尺寸为 (3 3× 2 4) mm2时 ,转速已达 (40× 1 0 4 )

新开发的几种核径迹应用技术

文章介绍 3种具有实用意义的核径迹新技术。这些技术是核径迹染色、核孔膜复制和利用核径迹制备金属微锥。

Preparation of Thin Palladium Composite Membranes and Application to Hydrogen/Nitrogen Separation

Thin palladium composite membranes were prepared by modified electroless plating method on a-alumina supports and a dense Pd/α-Al2O3 composite membrane with high hydrogen flux, good selectivity for hydrogen was obtained. It was tested in a single gas permeation system for hydrogen permeance and hydrogen selectivity over mtrogen. The hydrogen permeance of the corresponding membrane was ashigh as 2.45×10^-6mol·m^-2·s^-1.Pa^-1 and H2/N2 selectivityover700 at 623K and a pressure difference of 0.1MPa. The-main resistance of the composite membrane to H2 permeation lies in the aluminum ceramic support rather than the thin Pd layer.

Preparation of N, O-carboxymethyl Chitosan Composite Nanofiltration Membrane and Its Rejection Performance for the Fermentation Effluent from a Wine Factory

N, O-carboxymethyl chitosan （NOCC） composite nanofiltration （NF） membranes were prepared by coating and cross-linking. The fermentation effluent from a wine factory was treated with the resulting NOCC/polysulfone （PSF） composite NF membranes. The permeate flux and the removal efficiencies of the resulting NF membranes for the color, chemical oxygen demand （CODcr）, total organic carbon （TOC）, and conductivity of the fermentation effluent were investigated in relation to the driving pressure, the feed flow, and the operation time. The permeate flux and the removal efficiencies were found to increase with the increase of the driving pressure or the feed flow. At 0.40 MPa and ambient temperature the removal efficiencies were 95.5%, 70.7%, 72.6%, and 31.6% for color, CODcr, TOC, and conductivity, respectively. The membrane was found to be stable over a 10-h ooeration for the fermentation effluent treatment.

Fabrication of a Polyamide/Polysulfone Hollow Fiber Composite Membrane

With microporous polysulfone hollow fiber as the substrate, a polypiperazine amide nanofiltration composite membrane was prepared by interfacial polymerization in trimesoyl hexane solution as oil phase and piperazine aqueous solution as water phase. The conditions of the preparation, such as concentrations of monomer solutions, reaction time and temperature, annealing treatment, etc., were investigated. The hollow fiber composite herewith obtained showed high performance with water fluxes over 40 L·m -2·hr -1 and MgSO4 rejection of 93% under a pressure of 0.40 MPa.

Enhancing the separation performance by introducing bioadhesive bonding layer in composite pervaporation membranes for ethanol dehydration

A high performance composite membrane was prepared under the inspiration of bioadhesion principles for pervaporative dehydration of ethanol.Chitosan(CS)and polyacrylonitrile(PAN)ultrafiltration membranes were used as the active layer and the support layer,respectively.Guar gum(GG),a natural bioadhesive,was introduced as the intermediate bonding layer to improve the separation performance and stability of the fabricated CS/GG/PAN composite membranes.The contact angle of the GG layer was just between those of the CS layer and the PAN layer,minimizing the difference of hydrophilicity between the active layer and the support layer.The peeling strength of the composite membrane was significantly enhanced after the introduction of the GG layer.The effects of preparation conditions and operation conditions including GG concentration,operating temperature and ethanol concentration in feed on the pervaporation performance were investigated.The as-fabricated CS/GG/PAN composite membrane showed the optimum performance with a permeation flux of up to804 g·m-2·h-1and a separation factor higher than 1900.Besides,the composite membranes exhibited a desirable long-term operational stability.

Preparation and characterization of a composite membrane based on the asphaltene component of coal

Asphaltene-ceramic composite membranes were fabricated from ceramic supports and an asphaltene component, which was obtained from the separation of coal to give a kind of new carbonaceous precursor material. Using SEM and thermogravimetric analysis to measure the microstructure and properties of the asphaltene component allowed the porosity, permeability, and retention ratios to be determined. The results show that the asphaltene component can be regarded as a good carbon membrane precursor material because of its high carbon content and strong bonding capacity. When ceramic supports are impregnated with asphaltene colloid the asphaltene easily combines with the support surface and forms a good carbonaceous film after carbonization. Little of the asphaltene component permeates into the internal pores of the ceramic support. Although the number of coats applied to the substrate had little affect on the porosity of the asphaltene-ceramic composite membranes the permeability varied depend- ing upon the number of times the substrate was treated. The way bubbles escape from the film, and the phenomenon of coalescence, as affected by different film thicknesses also seem closely related to the number of coats. A composite membrane carbonized at a final temperature of 600℃ is relatively dense and the permeability of Fe（OH）3 colloid through it is very low. A membrane fired at 800℃ is porous and its permeability and retention of Fe（OH）3 colloid are 88 L/（m2 h MPa） and 85.3%, respectively when the trans-membrane pressure is 0.22 MPa.

Fabrication of SPES/Nano-TiO_2 Composite Ultrafiltration Membrane and Its Anti-fouling Mechanism

Membrane fouling is one of the major obstacles for reaching a high flux over a prolonged period of ultrafiltration（UF）process.In this study,a sulfonated-polyethersulfone（SPES）/nano-TiO2 composite UF membrane with good anti-fouling performance was fabricated by phase inversion and self-assembly methods.The TiO2 nanoparticle self-assembly on the SPES membrane surface was confirmed by X-ray photoelectron spectroscopy （XPS）and FT-IR spectrometer.The morphology and hydrophilicity were characterized by scanning electron microscopy（SEM）,atomic force microscopy（AFM）and contact angle goniometer,respectively.The anti-fouling mechanism of composite UF membrane was discussed through the analysis of the micro-structure and component of UF membrane surface.The results showed that the TiO2 content and the micro-structure of the composite UF membrane surface had great influence on the separation and anti-fouling performance.

Preparation of Palladium-Silica Conjugated Membrane for Selective Hydrogen Permeation

Palladium membranes were prepared on an α-alumina support bymetal-organic compound chemical vapor deposition (MOCVD) method frompalladium (II) acetate precursor. Permeation properties of hydrogenand helium gas were studied as a function of the number of times ofdeposition of palladium on the peeling off phenomenon of palladium,which is common in electroless plated membrane, was observed. Silicawas introduced into the pores to prevent the palladium grain frompeeling off. The palladium-silica conjugated membrane does not showthe peeling off phenomenon and can withstand the high temperature upto 800 deg. C which is the upper limit of our apparatus.

Radiation induced graft polymerization of multi-walled carbon nanotubes for superhydrophobic composite membrane preparation

Highly soluble multi-walled carbon nanotubes （MWNTs） were prepared by radiation-induced free radical graft polymerization of vinyl acetate （VAc） onto pristine MWNT surfaces. High resolution transmission electron microscopy （HR-TEM）, Fourier transform infrared （FT1R） spectroscopy, and micro-Raman spectroscopy were used to confirm that poly（vinyl acetate） （PVAc） had been successfully grafted onto the surface of the MWNTs. The effects of experimental parameters on the degree of graft- ing （DG） of PVAc were also investigated, including adsorbed dose, dose rate, initial monomer concentration, and solvents. The grafted MWNTs （MWNTs-g-PVAc） exhibited good solubility in common organic solvents at high mass fraction. In addition, a superhydrophobic composite membrane could be readily fabricated by vacuum filtration of MWNTs-g-PVAc onto a support- ing membrane, as was confirmed by water contact angle testing and visualization by scanning electron microscopy.

The fabrication and optimization of OTFT formaldehyde sensors based on Poly(3-hexythiophene)/ZnO composite films

Formaldehyde(HCHO),a colorless and pungent-smelling gas,is confirmed be a huge threat to human health.The detection of formaldehyde is necessary and important.The Poly(3-hexythiophene)(P3HT)/ZnO organic-inorganic composite thin film was fabricated and used as the sensitive layer of organic thin film transistors(OTFT) by spray-deposited method to detect HCHO at room temperature.The process parameters such as P3HT/ZnO weight ratios and airbrushed masses were optimized.The results showed that P3HT/ZnO OTFT exhibited good sensing response to HCHO.Airbrushed mass of 1ml was the optimal mass,and the 1:1 and 1:5 weight ratios of P3HT/ZnO exhibited better sensing properties compared with others.OTFT gas sensors based on P3HT/ZnO composite film provides a novel promising approach to the detection of HCHO.

Mesoporous polypyrrole-based graphene nanosheets anchoring redox polyoxometalate for all-solid-state micro-supercapacitors with enhanced volumetric capacitance

Micro-supercapacitors（MSCs） have emerged as one competitive candidate of high-performance, flexible, safe,portable and wearable energy storage devices. However, improving their electrochemical performance from electrode materials to assembled devices still remains huge challenges.Here, we for the first time synthesized two-dimensional（2D）,ultrathin, mesoporous polypyrrole-based graphene nanosheets uniformly anchored with redox polyoxometalate（mPPy@rGO-POM） by soft template approach. Further, using a layer-by-layer deposition and mask-assisted technique, the compactly stacked and sandwich-like hybrid film（mPGM）based on pseudocapacitive mPPy@rGO-POM nano sheets and electrochemically exfoliated graphene was directly fabricated as binder-and additive-free interdigital electrodes for all-solid-state planar micro-supercapacitors（mPGM-MSCs）. Notably, the resulted mPGM-MSCs exhibited outstanding areal capacitance（115 mF cm^-2）, remarkably enhanced volumetric capacitance（137 F cm^-3 at 1 mV s^-1） in comparison with MSCs based on the films of mPPy@rGO without POM anchoring（95 F cm^-3）, and non-porous polypyrrole-graphene（68 F cm^-3）.Further, mPGM-MSCs disclosed robust mechanical flexibility with ～96% of capacitance retention at a highly bending angle of 180°, and impressive parallel or serial interconnection for boosting capacitance or voltage output. As a consequence, our proposed strategy of filling the redox species into mesoporous graphene and other 2D nanosheets will open up new ways to manufacture high-compact and flexible energy storage devices ranging from supercapacitors to batteries.

Metal chalcogenide complex-mediated fabrication of Cu_2S film as counter electrode in quantum dot sensitized solar cells

Cu2S film onto FTO glass substrate was obtained to function as counter electrode for polysulfide redox reactions in CdS/CdSe co-sensitized solar cells by sintering after spraying a metal chalcogenide complex, N4H9Cu7S4 solution. Relative to Pt counter electrode, the Cu2S counter electrode provides greater electrocatalytic activity and lower charge transfer resistance. The pre- pared CuzS counter electrode represented nanoflower-like porous film which was composed of Cu2S nanosheets on FTO and had a higher surface area and lower sheet resistance than that of sulfided brass Cu2S counter electrode. An energy conversion efficiency of 3.62% was achieved using the metal chalcogenide complex-mediated fabricated Cu2S counter electrode for CdS/CdSe co-sensitized solar cells under 1 sun, AM 1.5 illumination.

Fabrication and Properties of Poly(vinylalcohol)-glycosaminoglycantype I Collagen Composite Membrane as Tissue Regeneration Scaffolds

The objective of this paper is to design a based on composite membrane with certain mechanical porous polyvinyl alcohol （PVA） strength and biocompatibilities serving as tissue regenerative scaffolds. PVA-glycosaminoglycan （GAG）-type I collagen （COL） composite membrane was fabricated by PVA with different molecular weight （Mw） and alcoholysis degree （AD） being blended with certain amounts of GAG and COL and dried at 38~C for 24 h. The water content of the composite membranes were from 61.9% to 95.1% and swelling ratio ranged from 123.6% to 621.7%. Scanning electron micro- scope （SEM） analysis proved that PVA-GAG-COL composite membrane has porous and homogenous structure. Biocompatibility test results showed that the composite membrane was nontoxic, which could promote adhesion and proliferation of fibroblasts on the com- posite membrane. In conclusion, PVA-GAG-COL composite membrane with high water content and swelling ratio, suitable mechanical strength and good biocompatibility, has potential in tissue engineering and regenerative medicine.

Preparation of bilayer/three-layer PEO-carbon nanotube composite thin films and their toluene-sensing application

The bilayer poly(ethylene oxide)/multiple-walled carbon nanotubes(PEO/MWCNTs) and three-layer PEO/MWCNTs/PEO composite thin films were fabricated with the spraying process on the interdigitated transducers(IDTs) as gas sensors for toluene-sensing application.Compared with the bilayer thin film sensor,the sensor with three-layer thin films exhibited higher response values and better recovery property.The microstructures of sensing films were characterized by scanning electron microscopy(SEM) to indicate that the better sensing response of three-layer thin films might be ascribed to the sufficient adsorption of toluene molecules on the surfaces of upper and bottom PEO films.The selectivity of the three-layer film sensor was further investigated by comparing responses upon exposure to different interference vapors with the response to toluene exposure,and much higher response was observed in the case of toluene.Good repeatability of the three-layer film sensor was also observed.