CTA高盐度苦咸水脱盐中空纤维反渗透膜

本文介绍高盐度苦咸水反渗透中空纤维膜的研制，主要涉及某些重要参数对纤维成型和膜性能的影响。     

Preparation and the luminescent properties of Tb3+-doped Gd2O3 fluorescent nanofibers via electrospinning

Tb(3+)-doped Gd(2)O(3) (Gd(2)O(3):Tb(3+)) nanofibers were prepared via a simple electrospinning technique using poly(ethylene oxide) (PEO) and rare-earth acetate tetrahydrates (Ln(CH(3)COO)(3)·4H(2)O (Ln = Gd, Tb)) as precursors. The obtained nanofibers have an average diameter of about 80 nm and are composed of pure cubic Gd(2)O(3) phase. A possible formation mechanism for the nanofibers is proposed on the basis of the experimental results, which reveals that PEO acts as the structure directing template during the whole electrospinning and subsequent calcination process. The luminescent properties of the nanofibers were investigated in detail. The nanofibers exhibit a favorable fluorescent property symbolized by the characteristic green emission (545 nm) resulting from the 5D4-->7F5 transition of Tb(3+). Concentration quenching occurs when the Tb(3+) concentration is 3 at.%, indicating that the Gd(2)O(3):Tb(3+) nanofibers have an optimum luminescent intensity under such a doping concentration.     

Distributed Privacy-Preserving Fusion Estimation Using Homomorphic Encryption

The privacy-preserving problem for distributed fusion estimation scheme is concerned in this paper. When legitimate user wants to obtain consistent information from multiple sensors, it always employs a fusion center (FC) to gather local data and compute distributed fusion estimates (DFEs). Due to the existence of potential eavesdropper, the data exchanged among sensors, FC and user imperatively require privacy preservation. Hence, we propose a distributed confidentiality fusion structure against eavesdropper by using Paillier homomorphic encryption approach. In this case, FC cannot acquire real values of local state estimates, while it only helps calculate encrypted DFEs. Then, the legitimate user can successfully obtain the true values of DFEs according to the encrypted information and secret keys, which is based on the homomorphism of encryption. Finally, an illustrative example is provided to verify the effectiveness of the proposed methods.     

The effects of pressure and temperature on the catalytic oxidation of hydrogen sulfide in natural gas and regeneration of the catalyst to recover the sulfur produced

The influence of pressure up to 5600 kPa and temperature up to 175 °C on the oxidation of low concentrations of H₂S in natural gas was studied in a fixed bed reactor over an activated carbon catalyst. Operation of this system at 5600 kPa provides higher catalyst activity (virtually 100% H₂S conversion) over a longer period of time and with lower selectivity to SO₂ than when operated at atmospheric pressure. The desorption of sulfur from a loaded catalyst occurs first from the macropores (> 100 nm) of the catalyst which contain a substantial portion of the sulfur load and then from the micropores (< 100 nm). This study also indicated that the sulfur recovery process is both rapid and effective at 327°C.     

Preparation and photocatalytic activity of nano-sized nickel molybdate (NiMoO4) doped bismuth titanate (Bi2Ti4O11) (NMBT) composite

Various compositions of nano-sized (NiMoO₄)_x-doped Bi₂Ti₄O₁₁ (x = 0.01, 0.05, 0.1) composites have been prepared by chemical solution decomposition (CSD) method using triethanolamine (TEA) as complexing agent. Ni(II) is one of reactive species on the catalyst surface and Mo(VI) ion helps to compensate the charge of the lattice. The photocatalysts based on the above compositions have been tested for photobleaching of methyl orange (MO) solution under Hg-lamp. The prepared nanopowders are characterized by XRD, EDAX, UV–vis spectra, specific surface area (BET), zeta potential, ESR and HRTEM analyses. The average particle size of nickel molybdate-doped bismuth titanate lies around 30 ± 2 nm measured from TEM. Result shows nickel molybdate-doped bismuth titanate (NiMoO₄)_x(Bi₂Ti₄O₁₁)_1−x (NM_xBT_1−x; x = 0.01) composite is found to be more photoactive compared all the compositions studied except degussa P25 titania.     

Studies on the contamination of feed molasses for continuous ethanol production in an immobilised yeast cell reactor

With the present world problem of fossil fuel limitations, alcohol production from renewable resources such as sugar cane molasses, particularly by continuous processes, has become important. In continuous processing, feed contamination problems could become critical. A useful inexpensive technique, which can minimise these problems when molasses is used as the substrate, is to ensure that the time period elapsing after dilution of molasses and before feeding to the reactor is minimal. Experiments were conducted to determine how long the clarified molasses feed solution could be kept under non-sterile conditions without affecting the performance of an immobilised whole cell reactor for alcohol production. For this purpose, the fastest growing contaminant (under the prevailing conditions) present in molasses feed solution was isolated by plating technique. From the initial total number of contaminant microorganisms in the feed solution, and from the experimentally determined generation time of the fastest growing contaminant cells, the safe period of storage of diluted molasses was calculated. This value was in reasonable agreement with the experimental observations.     

稀土硬质合金刀具的切削性能与机理研究

稀土硬质合金材料是国家重点科研专题之一。本文通过系统的切削试验，研究该材料用作金属切削刀具的性能特点；并通过扫描电镜和能谱分析等先进手段，揭示其切削机理。还对其潜在的技术、经济效益进行了分析。     

悬浮法高分子量聚乙烯树脂的颗粒特性研究

采用扫描电镜，图像分析，ＣＣｌ４吸收，表面孔径测定以及增塑剂吸收量测定方法研究了新型ＨＭＷＰＶＣ树脂的颗粒特性和增塑剂吸收性能。结果表明，国产ＨＭＷＰＶＣ树脂颗粒疏松多孔，增塑剂吸收程度优于通用型ＰＶＣ树脂，但其总体颗粒特性又较日本同类产品为差。同时，提出了ＨＭＷＰＶＣ的颗粒结构模型。     

DRIFT Studies of Adsorbed CO Over Sulfided K–Rh–Mo/Al2O3 Catalysts: Detection of Rh–Mo–S Phase

Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy was used to study the nature of active species in K–Rh–Co–MoS₂/Al₂O₃ catalyst by means of probing with CO molecule. The effects of K addition to Rh and interaction between Mo and Rh were studied with varying K and Mo loadings over 1 wt% Rh/Al₂O₃ catalyst. In sulfided Rh–Mo/Al₂O₃, the formation of Rh–Mo–S phase was evidenced first time by a band at 2,095 cm^?1. The introduction of Co to K–Rh–MoS₂/Al₂O₃ catalyst showed the existence of both Rh and Co promoted MoS₂ sites, but the CO absorption frequencies in DRIFT spectra are significantly at lower side compared to Co free Rh–Mo catalyst. The stabilities of CO band from Rh and Co promoted and unpromoted MoS₂ sites are studied at different temperatures. When activated carbon used as support, bands for both promoted and unpromoted MoS₂ sites were appeared, but the intensity of these bands were decreased largely compared to alumina based catalyst, resulted from the coverage of added K not only on the support surface but also on the active metal components due to the neutral nature of activated carbon.     

双重有源桥双向DC/DC变换器新型控制方法的研究

针对双重有源桥双向DC/DC变换器在nU1>U2且处于重载模式下一个周期内的工作状态进行分析,得到高频电感电流的变化规律及电感电流变化与开关管触发信号之间的关系。研究了一种采用变压器漏电感电流作为控制参量的新型移相控制方法,将电压误差放大信号作为变压器漏电感电流信号的给定,并对提出的控制方法进行分析。最后,基于Matlab/Simulink制作了一个仿真模型,验证了新型控制方法的正确性和有效性。