无胶筛分毛细管电泳对SNP分型的初步研究

建立了非涂层无胶筛分毛细管电泳对多个SNP位点快速分型的方法.采用长度为20 bp和40 bp的DNA片段为实验时象,对筛分介质的种类及其质量浓度、电泳缓冲溶液的浓度及其pH值、分离电压进行了优化,确定最合适的分离条件如下:6%PDMA为筛分介质,缓冲溶液TAPS浓度为100 mmol·L-1、pH值为8,分离电压为15 kV.并在此条件下成功地对3个SNP位点进行分型.结果表明,以PDMA为筛分介质的非涂层无胶筛分毛细管电泳方法用于SNP分型是可行的,而且具有特异性强、灵敏度高、重复性好、操作简单快速、结果直观等优点.     

电解质溶液研究进展

摘电解质溶液理论作为溶液理论的重要组成部分,研究较缺乏普适性、系统性以及规律总结。本文主要从溶液理论、半经验模型、统计学理论三个方面对电解质溶液热力学性质的最新研究及应用进展做了评述,认为Pitzer模型、NRTL局部组成模型是目前研究和应用最广的模型,分子模拟技术成为计算电解质溶液性质的重要方法,并提出了自己的观点。     

电解质溶液热力学模型的研究进展

从电解质溶液的经典理论、活度系数模型和近代统计力学理论三个方面,对电解溶液热力学模型的研究进展进行了综述。通过对活度系数模型的分类、组成和发展进行研究,预测电解质溶液热力学模型未来发展方向是从分子和离子角度研究其宏观热力学性质。     

含醇体系超额性质模型TDAM的导出和应用

本文针对含醇体系的特性,基于缔合溶液理论,导出了一个形式简单、物理意义明确的溶液模型——TDAM.由于TDAM模型中引入了较为合理的温度关系,仅需两套不同温度下的超额焓数据,即可进行其它温度下超额焓数据以及汽液平衡数据的推算.将TDAM模型对非极性、极性体系超额焓的关联结果与其它常见溶液模型(Wilson、W-C和QCSM等)进行了比较,以TDAM模型为最佳;对含醇体系汽液平衡数据也进行了同样的比较,TDAM模型关联结果优于或相当于其它溶液模型.将该模型用于超额焓和汽液平衡的推算,结果令人满意.     

治疗性DNA疫苗生产工艺及质量检测的研究

研究了治疗性DNA疫苗的大规模生产工艺.利用硫酸铵沉淀法和超滤技术对发酵菌体的碱裂解液进行预处理,除去发酵液中大量的RNA;然后依次用凝胶过滤层析、亲和层析和离子交换层析对DNA疫苗进行纯化;并对最终质粒DNA溶液进行全面的质量检测.结果表明,DNA疫苗总产率可达62%,各项质量指标均符合药用DNA疫苗质量标准.该纯化工艺操作简便、成本低,适用于大规模工业化生产.     

电解质溶液热力学性质的研究进展

从电解质溶液的经典理论、半经验模型和统计力学3方面综述了电解质溶液热力学性质的研究进展,并对各种理论和模型在理论与实践方面的局限性作了相关评述。从分子、离子角度对电解质溶液的热力学性质进行研究比较,探讨了其宏观热力学性质与微观结构的相关性。展望了电解质溶液热力学理论近期研究的热点和未来的发展方向。     

二元溶液表面张力的理论推算

<正>液体表面张力是化工传递过程中的重要物理量,因此对表面张力理论计算的研究一直十分活跃.时至今日,前人已建立了许多较为出色的纯液体及液体混合物表面张力的关联计算模型,但是工业过程常需要一些能进行预测计算的模型.有关液体混合物表面张力预测计算模型的研究,前人也已做了不少工作:Sprow和Prausnitz,基于Eckert和Prausnitz的研究成果,用溶解度参数法计算表面相活度系数,结合表面张力基本方程,建立了二元溶液表面张力的理论推算式,但该推算式只适用于简单分子溶液; Go ldsact等人从表面张力基本方程出发,假定主体相、表面相均为理想溶液,得到理想溶液表面张力的理论推算式;戎宗明等直接从Gibbs-Duhem方程得到的二元溶液表面张力的推算模型,在对一般     

我国振动筛理论研究及技术应用进展

鉴于振动筛在我国现代矿物加工行业中的重要性,结合近年来我国振动筛理论研究及技术应用进展,概述了我国振动筛振动理论研究热点,阐述了我国振动筛筛分机理与筛分方法研究现状,总结了我国振动筛技术研究的创新成果,介绍了各种先进技术在振动筛上的应用情况,同时针对我国振动筛理论研究及技术应用过程中存在的各种亟待解决的问题,提出了相应的对策和建议。最后结合我国振动筛行业面临的新形势,对其未来发展方向进行了展望。     

固体─超临界流体相平衡的分子热力学模型

从分子热力学基础出发提出一个适用于固体-超临界流体相平衡的理论模型，溶液中溶质的化学位分解为无限稀溶液化学位及溶质浓度效应两部.无限稀溶液化学位由简化的Oz方程计算，其中包括斥力贡献、局部组成及长程引力项浓度对化学位的贡献由作者根据Kirkwood-Buff溶液理论提出的修正Wilson模型计算．用45个二元系862个数据点对此模型进行检验并和PR方程（vdw-2混合规则）计算结果进行比较，本模型的平均绝对误差为11.7％，而PR方程的结果为14.9％，对极性溶剂体系的计算结果有显著改善.用此模型直接推算的萘-Co_2体系萘的偏摩尔焓和文献数据相吻合     

高效毛细管电泳分离机理的研究

应用色谱分离理论,综合考虑了分子扩散、进样量、电能消耗、电泳迁移等因素对高效毛细管电泳分离的影响,建立了高效毛细管电泳分离机理模型.以色氨酸为示踪样品进行实验,研究了电压、溶液浓度、进样量、毛细管管径等因素对理论板高度的影响,并与模型计算结果进行了比较.结果表明,本文所提出的模型能够较好地描述高效毛细管电泳的分离机理,该模型可作为优化操作参数和进行放大设计研究的基础.     

Efficient helium separation of graphitic carbon nitride membrane

An efficient membrane for helium separation from natural gas is quite crucial for cryogenic industries. However, most experimentally available membranes fail in separating helium from small molecules in natural gas, such as H₂, as well as in ³He/⁴He isotopes separation. Using first-principles calculations, we theoretically demonstrated that the already-synthesized graphitic carbon nitride (g-C₃N₄) has high efficiency in helium separation from the gas molecules (H₂, N₂, CO and CH₄) in natural gas and the noble gas molecules (Ne and Ar). The selectivity of He over H₂ molecule at room temperature is calculated to be as high as 10⁷. More interestingly, the g-C₃N₄ membrane can also serve as a quantum sieving membrane for ³He/⁴He separation with a predicted transmission ratio of 18 at 49 K, thus offers a combined means of both He and ³He isotope separation.     

MOFs分离膜在水系分离中的应用

MOFs作为一类具有三维孔结构的新型框架材料,在催化、储能和分离领域均有广泛的应用前景,而MOFs的水稳定性一直是限制其扩大应用的壁垒。随着水稳定性MOFs材料不断涌现以及人们对MOFs水稳定性机理认识的加深,众多的学者开始关注MOFs分离膜在水体系下物质分离的应用研究。综述了围绕MOFs分离膜在水系环境下的分离应用研究展开,概述了MOFs水稳定性的影响因素,MOFs分离膜的制备及其在染料废水处理、脱盐、重金属离子去除和离子选择性分离等领域的应用研究,并对MOFs分离膜未来发展趋势进行了展望。     

Novel Composite Membranes for Gas Separation: Preparation and Performance

High performance composite membranes based on molecular sieving silica (MSS) were synthesized using sols containing silicon co-polymers (methyltriethoxysilane and tetraethylorthosilicate). Alpha alumina supports were treated with hydrochloric acid prior to sol deposition. Permselectivity of CO2 over CH4 as high as 16.68 was achieved whilst permeability of CO2 up to 36.7 GPU (10–6 cm3 (STP) cm–2 · s–1 · cm Hg–1) was measured. The best membrane's permeability was finger printed during various stages of the synthesis process showing an increase in CO2/CH4 permselectivity by over 25 times from initial support condition (no membrane film) to the completion of pore structure tailoring. Transport measurement results indicate that the membrane pretreated with HCl has highest permselectivity and permeation rate. In particular, there is a definite cut-off pore size between 3.3 and 3.4 angstroms which is just below the kinetic diameters of Ar and CH4. This demonstrates that the mechanism for the separation in the prepared composite membrane is molecular sieving (activated diffusion), rather than Knudsen diffusion.     

Carbon Membranes Prepared from a Polymer Blend of Polyethylene Glycol and Polyetherimide

Through a dip‐coating technique, carbon membranes were produced from a polymer blend consisting of the thermally stable polymer polyetherimide (PEI) and the thermally labile polymer polyethylene glycol (PEG). The PEG/PEI carbon membranes were synthesized on an alumina support coated with an Al₂O₃ intermediate layer. The polymer blend ratio and carbonization temperature influenced the structure and permeation performance of the derived carbon membranes. The porosity of the PEG/PEI carbon membranes increased with higher PEG content in the blends. However, the derived carbon membranes tended to lose gas permeability with raising the carbonization temperatures. The carbon membranes were successfully optimized in order to achieve the highest CO₂/CH₄ and CO₂/N₂ selectivities.     

一/二价离子分离膜材料研究进展

一/二价离子分离膜在能源存储和转换、污染监测和控制、清洁工业过程等领域发挥重要作用。本文旨在回顾近年来一/二价离子分离膜材料的研究进展,重点综述聚合物膜、混合基质膜及金属有机骨架和二维材料等新型膜用于一/二价离子分离的研究现状,深入讨论界面聚合、层层组装、沉积、共混等不同制备方法对膜微结构和分离性能的影响,探讨一/二价离子分离膜面临的主要挑战和未来研究方向。     

A stable metal–organic framework with well-matched pore cavity for efficient acetylene separation

Acetylene, an important petrochemical feedstock, is the starting chemical to produce many polymer products. Separating C₂H₂ from its by-product mixtures is still an energy-consuming process and remains challenging. Here, we present a metal–organic framework[Zn₂(bpy)(btec)], with a desirable pore geometry and stable framework, which demonstrated a high separation performance of C₂H₂ from simulated mixtures. With the desirable pore dimension and hydrogen bonding sites, Zn₂(bpy)(btec) shows by far the both highest C₂H₂/C₂H₄ and C₂H₂/CO₂ uptake ratios, very high adsorption selectivities and moderately C₂H₂ uptake of 93.5 cm³/cm³ under 298 K and 1 atm. Not only straightforwardly produced high purity of C₂H₄, but also recovered high purity of C₂H₂ (>98%) in the regeneration process (>92% recovery). More notably, Zn₂(bpy)(btec) can be straightforwardly synthesized at a large scale under environmentally friendly conditions, and its good water/chemical stability, thermostability, and cyclic stability highlight the promise of this molecular sieving material for industrial C₂H₂ separation.     

Some factors affecting sieving performance and efficiency

Sieving or screening has been the oldest yet most important unit operation for industrial separation of solid particles or as a laboratory method in size analysis. A stack of sieves with decreasing mesh size is usually used. Alternatively, particles can be sifted in a fine to coarse order by multiple sieving steps with each step using a single sieve. The latter is referred to as reverse sieve method. This study compared the two methods for sieving performance and efficiency using flours made from soft white and hard white wheat, hulless barley and medium grain rice. Additional factors, including milling method (impact vs. abrasive), flour moisture (7% vs. 11%), duration of sieving (60 vs. 120 min), and tapping (percussion during sieving), were also investigated. Mass frequency and protein content of oversize fractions were measured. Results show that all the variables and their interactions had significant effects on sieving performance and efficiency. Among them, tapping was most important, followed by sieving duration, sieving method, milling method, flour type, and flour moisture. When other conditions were equal, the reverse sieve method always gave improved sieving efficiency over the stacked sieve method. The observation can be attributed to the beneficial effect of oversized particles on reducing sieve blinding by near or sub-sieve sized particles. Furthermore, the reverse sieve method also expanded the difference in protein content among sieved fractions. Because of its practical significance, this so far unreported effect would bear further confirmation of other sieving and screening conditions.     

Precise control on two-dimensional nanochannels at sub-nanometer level for customizable gas separation

Membranes with precise molecular sieving channels that break the permeability-selectivity trade-off are desirable for energy-efficient gas separation. Two-dimensional (2D) membranes sieve gas through their special interlayer channels between neighboring nanosheets. However, the regulation and precise control of the nanochannels that match well with the size of the gas molecules remains a big challenge. Herein, accurate tuning of the interlayer spacing of layered double hydroxide (LDH) membranes at sub-nanometer level was achieved by intercalation of Cl⁻, Br⁻, I⁻, and NO₃⁻ ions. Such high-precision control allows customizable gas separation by selecting specific LDH membranes with appropriate channels according to the size of the gas molecules. Two membranes were used for demonstration: Cl-LDH membrane shows high H₂ permeance of ∼1870 GPU and desirable selectivities for H₂/CO₂(81), H₂/N₂(197), H₂/CH₄(320), and H₂/C₃H₈(603); while I-LDH membrane displays CO₂ permeance of ∼1780 GPU and CO₂/N₂, CO₂/CH₄ selectivities of 182 and 297, respectively. The simultaneously high permeabilities and selectivities surpass the 2008 Robeson upper bounds. Molecular dynamics simulations quantitatively support the experiment results, further confirming the significant role of interlayer anions in the regulation of gas-sieving channels. Given the rich variability of layered spacing and interlayer microenvironment for LDH materials, this work provides a platform membrane for various molecular sieving, including gas separation, solvent purification, seawater desalination, and so on.     

Fine-tuned,molecular-composite,organosilica membranes for highly efficient propylene/propane separation via suitable pore size

Fine-tuned, molecular-composite, organosilica membranes were fabricated via the co-condensation of organosilica precursors bis(triethoxysilyl)acetylene (BTESA) and bis(triethoxysilyl)benzene (BTESB). Fourier transform infrared and UV–vis spectra confirmed the co-condensation behaviors of BTESA and BTESB. The evolution of the network structure indicated that the incorporated BTESB decreased the membrane pore size, which was determined by a modified gas translation model according to the steric effect of the phenyl groups. The incorporation of BTESB to BTESA finely tuned the membrane structure and endowed the resultant composite membrane with improved separation properties. The BTESAB 9:1 membrane (molar ratio of BTESA/BTESB was 9:1) exhibited high C₃H₆ permeance at 4.5 × 10⁻⁸ mol m⁻² s⁻¹ Pa⁻¹ and a C₃H₆/C₃H₈ permeance ratio of 33 at 50°C. One of the most important developments of this study involved clearly defining the relationship between membrane pore size and C₃H₆/C₃H₈ separation performance for organosilica membranes in single and binary separation systems.