超声强化多通道陶瓷膜微滤超细TiO2悬浮液

针对超声强化膜分离过程能耗高的问题,提出并设计了一种新型超声强化膜分离操作方式,并进行了超声强化陶瓷膜微滤超细TiO₂颗粒悬浮液的研究。考察了超声场参数、操作时间及溶液环境对多通道陶瓷膜微滤过程的影响规律,并分析了此操作方式强化陶瓷膜微滤颗粒悬浮体系的机理。结果表明,该操作方式能够获得较高膜通量恢复率及平均膜通量,同时超声能量消耗减小了90.0%以上;降低超声频率及提高功率,有利于膜通量恢复,在超声参数45 kHz和0.33 W·cm^-2条件下,膜通量恢复到初始值的94.0%;控制超声辐射时间0.167 min,微滤时间8 min时,平均膜通量提高了61.5%;降低悬浮液颗粒浓度及提高料液温度都有利于超声场强化陶瓷膜微滤过程。     

用微滤处理乳化含油废水

考察了ＰＶＤＦ膜和复合陶瓷膜的水通量，油截留率，以及膜堵塞等。研究结果表明：微波的水通量和油截留率均很高，透过液中油含量＜４０－２０ｍｇ／Ｌ。微波是一种很有应用前景的废水处理方法。另外，还讨论了在膜堵塞状态下，微波膜对溶于水小分子有机物的截留率。     

电场作用下的十字流膜滤初探

本文根据现代膜过滤技术中膜滤速度低下的原因，提出了附加电场的初步试验结果。试验研究表明直流电场会提高膜滤速率。而且有一个临界场强Ｅ＿ｃ存在，当所加电场略高于此值时将获得最佳的膜滤速率     

横流微滤技术现状与应用

<正> 横流微滤(CMF)已经成为一种获取纯滤液的过滤技术,它所采取的过滤介质为微孔滤膜,可以截留粒度约0.05μm的颗粒。因此,CMF的使用介于超滤(颗粒粒度约0.5×10~3μm)和普通过滤(颗粒粒度约     

利用离心力场作用强化微滤

综述了目前利用离心力场作用强化膜微滤的几种实施方法:旋转管式动态膜微滤,旋转流强化膜微滤和旋转盘式动态膜微滤;详细讨论了各法的代表结构、基本原理及国内外的实验研究成果;评述了各法的优缺点、发展状况和应用前景。     

拉伸力场对聚丙烯/石墨烯微片纳米复合材料形态和性能的影响

设计了2种挤出机头以产生不同加工力场,研究了聚丙烯（PP）/石墨烯微片（GNPs）纳米复合材料的微观形态、导电及导热性能,分析GNPs在PP基体中的分布形态对复合材料的性能影响。结果表明,收敛流道产生的拉伸力场对GNPs有剥离分散作用,减少GNPs团聚;加入静态混合器后产生的混沌混炼力场能进一步提高GNPs在PP中的分散均匀性,有利于构建导电导热网络,从而提高复合材料的导电导热性能;当GNPs含量为6 %(质量分数,下同)时,相比于无静态混合器的拉伸机头,在带静态混合器的拉伸机头挤出下,电导率增大了5个数量级,热导率提高了24.1 %。     

管式膜十字流微滤过程分析

分析了管式膜器中过滤悬浮液从膜管外壁向内壁渗透过滤的过程。以流体力学分析为基础 ,利用力平衡原理和多孔介质渗透定律 ,分析了该结构的过滤特性和滤饼形成特点及规律。     

旋转切向流PA管式膜微滤试验研究

实验研究了旋转切向流聚丙烯PA管式膜微滤。通过建立的旋转切向流强化微滤实验装置系统，测定了旋转直线切向流和旋转圆弧切向流PA管式膜在不同SiO2悬浮液农度和不同流体压力下的膜通量随时间的变化曲线。实验研究结果表明，旋转切向流强化微滤不但节能，而且系统结构简单。     

硅藻土微滤复合膜的制备工艺研究

本文以α-Al2O3微滤膜为载体,采用浸渍法在其上涂覆一层硅藻土制备硅藻土微滤复合膜,重点探讨了复合膜的制备工艺。实验表明,该硅藻土复合膜在低温下煅烧,可在反冲洗下将硅藻土剥离,从而实现载体膜的重复使用。     

微滤陶瓷膜结构特点及参数测定

本文采用电子显微照相——计算机图象分析处理技术,结合液体渗透法对微滤陶瓷膜的结构特点及参数进行了测定研究。测定结果吻合良好,表明两种方法结合可以准确、合理地评定陶瓷膜的结构和表征膜的性能参数。     

Liquid Oxygenation Improvement by Interaction of Bubbles and Vibration Fields

Gas bubble motion characteristics and bubble size are important factors in various technological processes involving the interaction between liquid and gaseous systems. The present work studies the effect of vibration fields on the characteristics of bubble motion and bubble size. Bubble retention time in the liquid (rise velocity) and bubble mean diameter were chosen as main parameters effecting the oxygen mass transfer rate. A device for mechanical vibration of the aerated liquid was used. The influence of the device design parameters on the chosen bubble parameters is studied experimentally and discussed in this work. The results obtained show the possibility of controlling bubble retention time and bubble size by employing vibration fields. Thus, by applying rather simple techniques, one can considerably improve the process of liquid oxygenation.     

无砾石管式地下渗滤系统的改进研究

针对传统无砾石管式地下渗滤系统存在的处理性能差,渗滤通量低两个问题,通过去掉包裹织物,提高渗滤管开孔率、改变开孔方式,设计了无砾石微孔管地下渗滤系统。通过实验研究表明,无砾石微孔管地下渗滤系统对COD、氨氮的去除率比传统管式系统分别提高了10.8%、12.7%,总磷去除率并无显著差异,ORP值提高约85mV,渗滤通量提高26.8%。无砾石微孔管地下渗滤系统和传统管式地下渗滤系统对COD、氨氮在土壤中的降解趋势线存在明显的差异,而对磷的去除过程几乎完全相同。     

Derivation of Class II Force Fields. III. Characterization of a Quantum Force Field for Alkanes

Recently, a quantum mechanical Class II force field (QMFF) was derived from a fit of HF/6–31G* ab initio energy and energy derivative data for alkanes, and a comparison of this quantum force field and the ab initio energy and energy derivatives was presented. In this work, the quantum force field is further evaluated with regard to its accuracy, and, more importantly, transferability. A detailed comparison between structures, frequencies, and energies calculated from quantum mechanics and from the classical analytical form is given for a set of molecules selected from both those used in the original training set and molecules selected from outside the training set. None of these properties were used directly in the original derivation of the force field. In order to assess the importance of anharmonic and coupling interactions that occur in and contribute to molecular energy surfaces, the results are compared to a diagonal quadratic force field. It is demonstrated that the QMFF functional form is capable of calculating the ab initio bond lengths, bond angles, torsion angles, and conformational energy differences to an rms accuracy of 0.003 Å, 0.4°, 1.2°, and 1.0 kcal/mol, respectively. This compares quite well to corresponding deviations of 0.006 Å, 0.8 Å, 2.3°, and 3.3 kcal/mol for a harmonic diagonal force field. Excluding three- or four-membered rings, the QMFF rms frequency deviations were 24 cm⁻¹, which again is much better than the ˜100 cm⁻¹ deviations for the harmonic diagonal force field. Larger average rms frequency deviations of 36 and 71 cm⁻¹ were found with QMFF for molecules with three- and four-membered rings. An in-depth analysis of C-H and C-C bond length, H-C-H, H-C-C, and C-C-C bond angle, and C-C-C-C torsion angle deviations is also presented, along with a similar characterization of frequency deviations in C-H stretching, C-C stretching, C-C-C bending, and torsion modes. It is concluded from these results that the use of quantum energy surfaces allows us to derive a (Class II) functional form which is not only more accurate, but also more transferable than previous generation force fields.     

原电池电动势法测定热力学函数实验改进

常规电动势法测定热力学函数存在电动势的温度系数不稳定,仍至无法估计或修正等问题。使用改进型盐桥,在20~50°C温度范围内,对比测定了两支参比电极(氯化银和甘汞电极)组成的原电池的电动势。结果表明,其温度系数为正(2.22×10~(-4)V℃~(-1)),反应的热力学函数变化值Δ_rG_m(298 K)、Δ_rS_m(298 K)和Δ_rH_m(298K)分别为-52.87 k J·mol~(-1)、-67.14 J·K~(-1)·mol~(-1)、-69.98 k J·mol~(-1)。与热力学函数理论值相比,其相对误差分别为3.7%、-2.4%和-2.5%。满足基础物理化学实验教学要求。     

提高聚氨酯磁漆涂层的结合力和外观质量

飞机制造中的钢铁和铝制零件大多喷涂聚氨酯磁漆。聚氨酯磁漆由于其成分的特殊性,涂覆后极易发生结合力和外观质量较差的质量问题。通过实验探索影响聚氨酯磁漆涂层结合力和外观的因素,并对这些影响因素进行了详细阐述。     

半钢子午线轮胎径向力八次谐波的改进

以235/50R19半钢子午线轮胎为例,研究轮胎径向力八次谐波（RF8H）的工艺改进措施。结果表明,在胎体膨胀率安全系数范围内尽量减小胎坯周长,并使夹持块与活络模块中心重叠,有效减小了轮胎径向力八次谐波数值,降低了轮胎噪声,提高了车辆乘坐舒适性。     

Particle Flocculation and Filtration by High-Gradient Magnetic Fields

Abstract

Flocculation and filtration of micrometer-sized particles in a high-gradient magnetic field (HGMF) were investigated. Experiments were conducted using a cryogenic magnet of 6 Tesla maximum strength. Hematite particles were used for flocculation and filtration experiments. A new approach of using magnetic fields to enhance separation of weakly magnetic particles was also investigated. This approach is based on magnetic seeding which involves flocculation of existing nonmagnetic particles with injected paramagnetic particles. A particle-flocculation model was developed based on trajectory analysis. External forces due to gravity and magnetism, and interparticle forces such as electrostatic, hydrodynamic, magnetic dipole, and van der Waals forces, were taken into consideration in these models.

     

原电池电动势测定实验的改进

从锌电极的制备方法和参比电极的使用与维护两方面对原电池电动势测定实验进行了一些改进,提高了实验测量值的精确度,同时也减少了对环境污染。     

浓差电池电动势测定方法的改进研究

浓差电池电动势的测定是原电池电动势测定实验的一部分,现行实验教材中的测定方法是不同浓度的电解质溶液通过盐桥连接。本文从改进传统的盐桥方法出发,采用双联电池的方法来对浓差电池电动势的测定进行了探索,发现改进后的实验结果基本上可以和传统盐桥方法接近。     

Quantum-Mechanical Calculations of Molecular Force Fields at the SCF Ab Initio Level Methyl Halides as Test Cases

The possibilities of the present quantum-chemistry methods for calculating the vibrational properties of polyatomic molecules have been investigated, taking the CH₃X series (X = F, Cl, Br, I) as bench tests. Finite-difference computations carried out with various basis sets at the SCF ab initio level on methyl fluoride bring out the performance of the LCAO-MO method as concerns the prediction of molecular force constants and integrated infrared intensities. Extension of these calculations to other halides is made possible using pseudo-potentials for the interaction between the atomic cores and the valence-shell electrons of the molecule. The atomic force field parameters defined in terms of Cartesian displacement coordinates suffer from a certain lack of transferability, apparently due to the variations of the chemical bonding effects when passing from fluorine to iodine.