共查询到20条相似文献,搜索用时 46 毫秒
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细胞对硅橡胶复合膜渗透蒸发分离性能的影响 总被引:4,自引:0,他引:4
利用自制的硅橡胶复合膜对乙醇-水模型溶液、含有干酵母的乙醇-水模型溶液、以及实际发酵液进行渗透蒸发分离乙醇实验,研究了细胞对膜性能的影响、结果表明:与纯乙醇模型溶液的分离相比,膜对含有干酵母的乙醇-水模型溶液、真实发酵液的分离表现出更好的性能,显示细胞的存在和活动对膜传质有一定的促进作用.连续发酵过程中,在一定的细胞浓度下(10g/L),硅橡胶膜维持了长期稳定的分离性能;产品乙醇的有效分离降低了其对酵母细胞的抑制作用,使沉积在膜面上的细胞层促进了膜的分离性能;但提高细胞浓度(15g/L)后却因更厚的细胞层的堆积造成膜面传递状况劣化,使膜性能下降.因此发酵液中的细胞浓度、膜面上的细胞沉积以及膜性能之间存在一种最佳的相互促进和搭配关系. 相似文献
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管状Silicalite—1分子筛膜的乙醇/水渗透汽化分离性能 总被引:4,自引:1,他引:3
采用原位水热合成的方法在管状α- Al2 O3 基膜上合成了 Silicalite - 1 分子筛膜. X R D、 S E M、 E D X 和气体渗透等表征方法表明该膜没有裂缺.研究了原料液中乙醇浓度和渗透温度对乙醇/ 水渗透汽化分离的影响.研究发现,当温度为30 ℃、原料液乙醇的摩尔分数为1 .2 % 时,乙醇/水的分离系数为60 ,透量为3 .1 mol/( m 2·h) ;温度升高,分离系数稍有下降,透量大大提高;当温度为60 ℃、原料液乙醇浓度不变,乙醇/ 水的分离系数为46 ,透量为13 .3 mol/( m 2·h) .原料液中乙醇浓度增加,乙醇/ 水的分离系数有一最大值;透量则随原料液中乙醇浓度的增加而降低.吸附- 扩散机理很好地解释了实验结果. 相似文献
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研究了醇水混合液体系在经交联的聚乙二醇/壳聚糖共混膜中的渗透蒸发分离性能.讨论了共混膜组成、料液浓度和温度、膜下侧压力等对渗透蒸发性能的影响.结果发现聚乙二醇的掺入能大大提高壳聚糖膜的渗透通量,但分离因子降低.当料液乙醇质量分数为80%时,渗透通量及分离因子都随温度的升高而增加.料液中加入少量ZrOCl2能把分离因子从原来的8.8提高到74.同时发现膜下游侧压力不仅仅影响渗透组分在膜表面的蒸发,还影响整个渗透蒸发传质过程. 相似文献
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渗透汽化膜行为为研究(I) 总被引:4,自引:0,他引:4
讨论了渗透汽化膜的渗透行为,以乙醇--水混合溶液为进料,在全浓度范围内,分别 4张不同硫酸交联程度的悫聚糖膜的渗透汽化性能及平衡溶解吸附性能,结果表明,硫酸交联增强了水的渗透,抑制了醇的渗透,从而使膜分离性能明显改善,膜对水及乙醇的透量与膜对水及乙醇的溶胀度之间存在明显的对应关系,在引入溶解吸附分离系数α3和扩散蒸发分离系数aDV后计算表明,膜的分离性能主要取决于水和乙醇在膜界上的溶解分配平衡。 相似文献
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壳聚糖/羧甲基纤维素聚电解质络合物膜的乙醇/水渗透汽化性能研究 总被引:1,自引:1,他引:0
采用壳聚糖和羧甲基纤维素进行聚离子反应.制备聚电解质络合物膜。该膜用于乙醇/水的渗透汽化分离,显示具有优先透水性,在乙醇浓度90%,温度60℃下,渗透通量和分离系数分别达197g/m2·h,1588。随料液乙醇浓度的增加,膜渗透通量下降,而分离系数增加,分离系数在乙醇浓度90%左右有一极大值。随温度升高,膜渗透通量和分离系数同步上升,渗透通量随温度的关系符合Arrhe-nius方程,渗透汽化表现活化能为34kJ/mol。 相似文献
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壳聚糖膜渗透汽化传递行为的研究 总被引:3,自引:3,他引:0
以壳聚糖膜及硫酸交联壳聚糖膜为基础、以乙醇-水体系为研究对象,考察了浓度、温度、交联对壳聚糖膜以及硫酸交联壳聚糖膜的传递行为的影响。实验结果表明,对壳聚膜糖膜和和硫酸交联壳聚糖膜来说,渗透通量与分离性能强烈地取决于原料组成。组发在膜内溶胀分配关系随原料浓度的改变而改变,这种溶胀过程的热力学分配关系直接支配着渗透气化的分离性能。随着温度的上升,乙醇与水的渗透通量急剧增加,而溶胀度变化不大。表明在一定 相似文献
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Photostriction is the superposition of a photovoltaic and piezoelectric effects. In this study, photostrictive effects in the perovskite (Pb, La) (Zr, Ti)O3 were investigated as a function of B-site impurity doping. Donor doping was found to reduce both the grain size and room-temperature dielectric constant, influencing photovoltaic response. WO3 and Ta2O5 doping increase the photovoltaic response, but do not significantly affect the piezoelectric effect in this material. Maximum photostriction is obtained for samples with 0.4 at% WO3 doped or 1 at% Ta2O5 doped PLZT 相似文献
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AbstractThe temperature effects on the intensity profile, self-deflection process, and stability of (1 + 1)-dimensional steady-state bright solitons resulting from both the linear and quadratic electro-optic effects are comprehensively analyzed. Moreover, three physical factors, i.e. diffusion effect, dark irradiance, and the dielectric constant, have been investigated through the theoretical analysis to determine which one dominates the temperature dependence of intensity profile and self-deflection of bright solitons. It is also found that the incident beam evolves into stable bright solitons in the vicinity of initial temperature, but oscillates or even collapses when the crystal temperature deviates significantly from the initial temperature. 相似文献
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We report the observation of self-focusing effects in organic photorefractive films based on a carbazole derivative and sensitizer 2,4,7-trinitro-9-fluorenone at 632.8 nm wavelength without applying a biased field, owing to the orientationally enhanced photorefractive nonlinearity caused by photopolymerization of the carbazole derivative. The experiment was repeated in three samples with different sensitizer doping percentages and similar phenomena were observed. 相似文献
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Surface effect aero-hydrodynamics, as one of the influencing factors in the design and operation of wing-in-ground effect
vehicles, is briefly illustrated. Some important issues are discussed. These include high lift/drag configuration, power augmented
ram, flight stability and control and wind-wave effects on aerodynamics. 相似文献
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Richa Pandey Gaurav Vats Jae Yun Chris R. Bowen Anita W. Y. Ho‐Baillie Jan Seidel Keith Tobias Butler Sang Il Seok 《Advanced materials (Deerfield Beach, Fla.)》2019,31(43)
An insight into the analogies, state‐of‐the‐art technologies, concepts, and prospects under the umbrella of perovskite materials (both inorganic–organic hybrid halide perovskites and ferroelectric perovskites) for future multifunctional energy conversion and storage devices is provided. Often, these are considered entirely different branches of research; however, considering them simultaneously and holistically can provide several new opportunities. Recent advancements have highlighted the potential of hybrid perovskites for high‐efficiency solar cells. The intrinsic polar properties of these materials, including the potential for ferroelectricity, provide additional possibilities for simultaneously exploiting several energy conversion mechanisms such as the piezoelectric, pyroelectric, and thermoelectric effect and electrical energy storage. The presence of these phenomena can support the performance of perovskite solar cells. The energy conversion using these effects (piezo‐, pyro‐, and thermoelectric effect) can also be enhanced by a change in the light intensity. Thus, there lies a range of possibilities for tuning the structural, electronic, optical, and magnetic properties of perovskites to simultaneously harvest energy using more than one mechanism to realize an improved efficiency. This requires a basic understanding of concepts, mechanisms, corresponding material properties, and the underlying physics involved with these effects. 相似文献
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S. Bouzgarrou Na. Sghaier M.M. Ben Salem A. Souifi A. Kalboussi 《Materials science & engineering. C, Materials for biological applications》2008,28(5-6):676-679
The aim of this work is to study the origin of parasitic effects observed on the output characteristics of InAlAs/InGaAs/InP HEMTs with various buffer layers. Ids − Vds measurements as a function of the temperature have first been performed. Several anomalies were observed such as kink and hysteresis effects. C-DLTS measurements have also been performed. From the obtained results, we have established a strong correlation between parasitic effects observed on the output characteristics and deep levels located near the buffer layer interface. 相似文献
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In this paper, a microchannel-based cryocooler consisting of a compressor, a recuperator and a cold heat exchanger has been developed to study the feasibility of cryogenic cooling by the use of Joule-Thomson effect and Bernoulli effect. A set of governing equations including Bernoulli equations and energy equations are introduced and the performance of the cooler is calculated. The influences of some working conditions and structure parameters on the performance of coolers are discussed in details. 相似文献