介电失配度对沸石电流变液界面极化的影响

利用介电谱方法研究了NaA沸石/硅油和NaA沸石/煤油两种电流变液的介电行为, 测量发现两体系在10⁵ Hz处均出现明显的弛豫现象. 采用单弛豫Cole-Cole函数拟合各体系的介电参数, 结果表明在相同体积分数条件下硅油体系具有较大的介电增量(?ε), 且两体系的介电增量与体积分数(φ)均服从?ε＝4ε_mφ的函数关系. 通过计算和分析粒子与介质间介电失配程度, 阐明了油介质的介电常数(ε_m)对于沸石电流变液界面极化强度的贡献. 此外研究了吸附水对沸石电流变液界面极化的影响, 结果发现水的吸附对于体系的?ε值没有影响, 但明显降低了弛豫时间, 证明吸附水对沸石电流变液的界面极化率具有增强作用.     

稀土PMMA包裹硅铝氧烷凝胶的电流变效应

用聚甲基丙烯酸甲酯（PMMA）对由水玻璃,硝酸铝和α－甲基丙烯酸形成的硅铝氧烷溶胶进行包裹,得到PMMA包裹的硅铝氧烷凝胶,同时在反应过程中用稀土离子进行掺杂,得到的稀土掺杂PMMA微囊粉末加入到甲基硅油中得到稳定的悬浮液,加载电场后发现其电流变效应显著提高,在一定浓度下与未掺杂体系相比即时粘度从95Pa.s提高到178Pas.s。     

电流变液体的研究进展

电流变液体自从20世纪40年代首次发现以来,由于其广泛的工程应用前景以及潜在的巨大经济和社会效益,已经成为众多研究领域的一个热点.本文综述了电流变液体的组成、电流变材料的研究进展、影响电流变效应的主要因素以及电流变液体研究的应用进展.     

双离子AB交联型聚醚类固体电解质及其电流变液的性能

将α，ω－双甲基丙烯酰氧基封端的聚乙二醇与高氯酸锂络合，分别用溶液聚合和反相悬浮聚合合成了双离子ＡＢ交联型聚醚类高分子固体电解质（ＡＢＣＰＥ２）及其组成的无水电流变（ＥＲ）液．研究了ＡＢＣＰＥ２本身的离子导电性和含ＡＢＣＰＥ２的ＥＲ液的活性和电性能，并用扫描电镜表征了ＥＲ液中的粒子．获得了离子导电率高达８．０×１０－５Ｓ／ｃｍ（２５℃）的高分子固体电解质和活性较高的无水ＥＲ液．     

二氧化硅负载胺丙基硅烷电流变流体

研究用二氧化硅负载胺丙基三乙氧基硅烷［ＮＨ２（ＣＨ２）３Ｓｉ（ＯＥｔ）３］作为分散颗粒，制备无水型的电流变（ＥＲ）流体．考察电场强度（Ｅ）、剪切速率（γ·）、分散颗粒含量、分散介质种类以及极性小分子等因素对ＥＲ流体流变性能的影响．结果发现，以硅油为分散介质，含分散颗粒为１５％（ｇ／ｍｌ）的流体，不添加任何活化剂，在γ·为８０６６ｓ－１时，Ｅ从０升至１６６６ｋＶ／ｍｍ，流体的表现粘度（ηａ）从０３９６Ｐａ．ｓ增大到１６６６８Ｐａ．ｓ．γ·提高，ηａ降低．分散颗粒含量增加，ηａ增大．用硅油作分散介质，ＥＲ效应比用矿物油或石蜡油显著．加入极性小分子苯胺，可以增强流体的ＥＲ效应，但随着苯胺含量增多，漏电流密度也增大．     

电流变阻尼器的抗冲击性能研究

从理论和试验两个方面研究了所设计的电流变阻尼器在大冲击下的抗冲击性能,分析了电流变液性能与阻尼器结构参数对抗冲击性能的影响.认为采用高性能的电流变液体及改变结构参数,都可以使电流变阻尼器的高速缓冲性能提高.电流变液流速对电流变液的屈服应力影响显著,其值随流速的增加按指数规律减小.从定性、定量两个方面分析了电流变阻尼器作为阻尼器效果不明显的原因为:由电流变效应引起的阻尼力在整个液压阻力中所占比例太小,不能通过改变电压来使液压阻力具有很大的调节可控范围.     

沸石电流变液材料的研究

系统地研究了沸石的由离子类型、数目、骨架的孔道大小和结构特性对沸石电流变液性能的影响. 证实了阳离子在电场中的迁移所引起的晶粒极化是Y，A和M等沸石电流变特性的基础，指出了较大的孔径和具有足够多易迁移的阳离子是该类沸石具有较好电流变性的的前提．根据NaZSM－5沸石在高电场中与其它沸石表现不同，具有屈服应力大而漏电流小的特点，提出了沸石晶粒极化还可能存在的另一种新的晶格变形机理．     

高性能石油焦颗粒电流变液的研究

采用未经精制的石油催化裂化油浆的一步炭化产物,研究了将其作为电流变液粒子的可能性、条件和电流变性能.研究结果表明,经由油浆热转化所得焦化颗粒配制的电流变液的力学性能,在2 kV/mm直流场强下可达2 kPa以上,电流密度不超过60 μA/cm2,长期静置颗粒无明显沉降,是一种性能优良的实用型电流变液.     

自旋阀多层膜的电化学制备及其巨磁电阻效应

采用双槽控电位电沉积法在n-Si(111)基体上以NiFe 薄膜为缓冲层制备了[Ni80Fe20/Cu/Co/Cu]n自旋阀多层膜, 并确定了电沉积的工艺条件. 利用X射线衍射(XRD)表征了自旋阀多层膜的超晶格结构, 研究了NiFe缓冲层对自旋阀生长取向的影响. 采用四探针法研究了各子层厚度对自旋阀巨磁电阻效应的影响, 通过振动样品磁强计(VSM)测试了自旋阀的磁滞回线. 自旋阀的巨磁电阻(GMR)值最初随着铜层厚度的变化并发生周期性振荡, Cu 层厚度为3.6 nm时, GMR 达到最大值,随后逐渐减小. 随着Co层和NiFe 层厚度的增大, GMR 值的变化趋势均为先增大后减小. 当自旋阀的结构为NiFe(25 nm)/[Cu(3.6 nm)/Co(1.2 nm)/Cu(3.6 nm)/NiFe(2.8 nm)]30时, GMR 值可达5.4%, 对应的磁电阻灵敏度(SV)为0.2%·Oe-1, 饱和磁场仅为350 Oe.     

用光学方法研究玻璃微珠电流变液颗粒间的相互作用

运用一套适合研究颗粒间相互作用的双光镊系统,通过对颗粒聚集时间的测量,得出颗粒聚集时间和电场的平方成反比.这是第一次用电流变液颗粒在动态情况下直接验证电偶极子对间的相互作用.发展了一套使用高速CCD摄像机进行扩散波谱(DWS)测量的方法,首次实时测量具有颗粒结构的非各态历经体系的自相关函数,以研究电流变液机理,得到了玻璃微珠电流变液的结构响应时间和力的响应时间;测量了不同电场下体系相关函数的特征衰减时间随时间的变化.在不同电场下测量扩散系数可以反映出相互作用力与电场的平方成正比.     

Analysis and Testing of Automotive MR Fluid Shock Absorber Based on Poiseuille Flow Mode

Analysis methodology and design theory of magnetorheological fluid (MR fluid) shock absorber based on of Poiseuille flow mode have been parented using Newton fluid model nonlinear Bingham plastic model. In the light of the technician requirements for Changan mini-automobile, a MR fluid shock absorber has been designed and fabricated using commercial MR fluid. We have validated experimentally the nonlinear MR fluid shock absorber model. The experimental results reveal that the analysis methodology and design theory is reasonable and the MR fluid shock absorber for a specific application can be designed according to the design methodology developed.     

Effects of medium oil on electroresponsive characteristics of chitosan suspensions

Biocompatible chitosan particle suspensions in host oils of corn, soybean, and silicone were prepared and their electrorheological (ER) characteristics were examined under the imposition of electric fields. The effects of the weight concentration of particulate chitosan and the strength of the applied electric field on ER response in the various chitosan particle suspensions were investigated via measurements of rheological properties including flow curve, shear viscosity, and yield stress. The yield stresses of the three different chitosan–oil systems showed different values of slope in the electric field, but all data were found to fit well with our previously proposed universal scaling function.     

Effect of polymerization temperature on polyaniline based electrorheological suspensions

As one of the intrinsically polarizable materials used in electrorheological (ER) fluid, polyaniline was synthesized by the chemical oxidation of aniline with ammonium peroxysulfate. ER fluids were prepared by dispersing polyaniline particles in silicone oil, and their rheological properties were measured. The effect of the polymerization temperature of polyaniline on its ER characteristics was investigated. ER fluids with polyaniline particles synthesized at −10°C (PA-10) showed the best ER performance (yield stress) compared with those synthesized at higher temperatures. A difference in the flow behavior of the ER fluids was also investigated through the dielectric spectra of ER fluids. Received: 24 March 1988 Accepted: 3 August 1998     

JP-10点火延时的激波管研究

JP-10 (exo-tetrahydrodicyclopentadiene, C10H16) ignition delay times were measured in a preheated shock tube. The vapor pressures of the JP-10 were measured directly by using a high-precision vacuum gauge, to remedy the difficulty in determining the gaseous concentrations of heavy hydrocarbon fuel arising from the adsorption on the wall in shock tube experiments. The whole variation of pressure and emission of the OH or CH radicals were observed in the ignition process by a pressure transducer and a photomultiplier with a monochromator. The emission of the OH or CH radicals was used to identify the time to ignition. Experiments were performed over the pressure range of 151-556 kPa, temperature range of 1000-2100 K, fuel concentrations of 0.1%-0.55% mole fraction, and stoichiometric ratios of 0.25, 0.5, 1.0 and 2.0. The experimental results show that for the lower and higher temperature ranges, there are different dependency relationships of the ignition time on the temperature and the concentrations of JP-10 and oxygen.     

Differences in the electrorheological response of a particle suspension under direct current and alternating current electric fields

We have observed an unusual reduction of shear stress with increasing shear rate under direct current electric fields, for an electrorheological fluid composed of sulfonated poly(styrene-co-divinylbenzene) particles dispersed in silicone oil. At all shear rates, the shear stress under the electric field is larger than that in the absence of the field, indicating that there is still some field-induced agglomeration of the particles. In contrast, the behavior under alternating current electric fields is the Bingham-fluid-type response commonly observed with electrorheological fluids. It is suggested that the conventional dipole–dipole interaction approach based on simplified microstructural models would be unable to explain these phenomena. Received: 27 November 2000 Accepted: 22 May 2001     

Recycling Valuable Metals from Spent Lithium-Ion Batteries Using Carbothermal Shock Method

Pyrometallurgy technique is usually applied as a pretreatment to enhance the leaching efficiencies in the hydrometallurgy process for recovering valuable metals from spent lithium-ion batteries. However, traditional pyrometallurgy processes are energy and time consuming. Here, we report a carbothermal shock (CTS) method for reducing LiNi_0.3Co_0.2Mn_0.5O₂ (NCM325) cathode materials with uniform temperature distribution, high heating and cooling rates, high temperatures, and ultrafast reaction times. Li can be selectively leached through water leaching after CTS process with an efficiency of >90 %. Ni, Co, and Mn are recovered by dilute acid leaching with efficiencies >98 %. The CTS reduction strategy is feasible for various spent cathode materials, including NCM111, NCM523, NCM622, NCM811, LiCoO₂, and LiMn₂O₄. The CTS process, with its low energy consumption and potential scale application, provides an efficient and environmentally friendly way for recovering spent lithium-ion batteries.     

Comment on “Preparation and electrorheological properties of triethanolamine-modified TiO2”

Comments on the recent report of electrorheological (ER) properties of an organic modified titanium dioxide with considerably high yield stress are given based on the analysis of its yield stress data as a function of applied electric field strengths. Using our previously reported universal yield stress equation and critical electric field strengths deduced, it is found that we can collapse their data onto a single curve.     

Comment on "Electrorheological behavior of copper phthalocyanine-doped mesoporous TiO2 suspensions"

We comment on the electrorheological (ER) behavior of copper phthalocyanine (CuPC)-doped mesoporous TiO(2) suspensions. Our Cole-Cole plot not only fits the dielectric spectra of the two CuPC-doped mesoporous TiO(2) templated ER fluids with CuPC/cetyltrimethylammonium (CTAB) molar ratios of 0.10 and 0.15, respectively, but also provides a better explanation of their polarizability by differentiating their ER performance.     

基于激波管装置的乙烯氧化实验研究与动力学机理分析

在乙烯/氧气化学计量比为1,温度1092-1743 K,压力1.3-3.0 atm (1 atm = 101325 Pa)范围内,利用激波管测量了在摩尔分数为96%和75%两种不同氩气稀释度工况下的乙烯/氧气/氩气反应体系的着火延迟时间。实验结果表明,乙烯着火延迟时间在低稀释度下比高稀释度下短,着火延迟时间的对数与温度的倒数成良好线性关系,随着温度增加着火延迟时间缩短。此外,低稀释度下,能观察到爆轰(或者爆燃转爆轰)现象,而在高稀释度下,未发生爆轰现象。将四种不同机理模拟结果与实验结果比较,发现LLNL机理与实验结果吻合得较好。反应路径分析研究表明,稀释度对乙烯氧化反应路径无影响,而温度影响较大,温度增加,乙烯消耗路径由四条减少为三条,反应C₂H₄ + H (+ M) = C₂H₅ (+ M)由正向消耗乙烯变为逆向生成乙烯。