A mathematical model of a fluidized bed reactor for the continuous production of solvents by immobilized Clostridium acetobutylicum

A fluidized bed reactor has been employed for the continuous production of solvents from whey permeate using cells of Clostridium acetobutylicum immobilized by adsorption onto bonechar. Substrate diffusion equations have been developed for the bioparticles, and a mathematical model has been advanced to describe the operation of the reactor. The model was fitted to the experimental data using the concept that not all of the biomass within the reactor was active in solvent production. On this basis, less than 5% was ‘active’ biomass.     

支持属性撤销的适应性安全属性基加密方案

Attribute revocation is inevitable and also important for Attribute-Based Encryption (ABE) in practice. However, little attention has been paid to this issue, and it remains one of the main obstacles for the application of ABE. Most of existing ABE schemes support attribute revocation work under indirect revocation model such that all the user's private keys will be affected when the revocation events occur. Though some ABE schemes have realized revocation under direct revocation model such that the revocation list is embedded in the ciphertext and none of the user's private keys will be affected by revocation, they mostly focused on the user revocation that revokes the user's whole attributes, or they can only be proven to be selectively secure. In this paper, we first define a model of adaptively secure ABE supporting the attribute revocation under direct revocation model. Then we propose a Key-Policy ABE (KP-ABE) scheme and a Ciphertext-Policy ABE (CP-ABE) scheme on composite order bilinear groups. Finally, we prove our schemes to be adaptively secure by employing the methodology of dual system encryption.     

渗透汽化法从丙酮-丁醇-乙醇中分离浓缩丁醇

发酵法生产丁醇的产物质量浓度很低,为了实现丁醇的高效分离浓缩,文中采用渗透汽化膜分离技术对模型发酵液(丙酮、丁醇、乙醇混合溶液,ABE)进行浓缩实验。结果表明:随着温度、真空度、错流速度、料液质量浓度的增大,丁醇通量上升;渗透汽化膜对丁醇选择性在温度50℃时最佳,并随真空度的减小而减小,随料液质量浓度的增大而降低。实验证明,渗透汽化法能实现丁醇的高效分离浓缩,并且利用串联阻力溶解扩散模型可较好地预测ABE溶液体系中各组分的传质和分离效果。     

自适应安全的带关键字搜索的外包属性基加密方案

为同时解决属性基加密（ABE）方案的计算成本过高和云服务器中数据查找效率低下的问题,提出了一种带关键字搜索的外包属性基加密（OABE-KS）方案。首先,使用外包计算技术将加解密用户的本地计算成本降低到常量级;然后,由加密用户和解密用户分别生成对应关键字的索引和陷门,并由云服务器为其进行匹配,在此之后云服务器会将匹配成功的结果返回给解密用户。在合数阶群下证明了所提方案是自适应安全的。根据实验分析可知,属性数量从10个到100个变化的过程中,该方案各个阶段的运行时间基本不变,可见该方案在各个阶段的运行时间不随属性数量的变化而变化。实验结果表明,该方案适合应用在资源受限的设备上,使其在实际应用中不受属性数量变化的影响。     

基于属性加密的广域信息管理的授权方法

为了解决广域信息管理(system wide information management,SWIM)信息安全问题,根据SWIM面向服务的系统架构(service-oriented architecture,SOA)的特点,设计SWIM的访问策略,提出了一种基于属性密码(attribute-based encryption,ABE)的授权方法.该方法根据SWIM访问结构中分布性、异构性和动态性的特点,采用密文访问策略(cipher policy-attribute based encryption,CP-ABE)实现.在模拟环境中对该方法进行仿真实验和安全性分析,实验结果表明:该方法支持SWIM航空用户细粒度的授权,降低了SWIM授权管理的复杂度,提高了SWIM系统的安全性.     

基于始终最佳体验的终端聚合的研究与实现*

统一业务终端通过分布式的终端设备协同提供应用体验,是B3G系统终端架构的一个发展方向.统一业务终端形成的终端业务环境提供始终最佳体验的服务模式,并主要体现在其对分布式终端组件的动态聚合重构上.在动态重构聚合的实现中,首先对体验质量进行量化建模,将各分布式终端的能力映射到能力服务器(CS),推导出满意度的评估函数及其约束条件,ABE服务模型.其次,基于此服务模型详细设计出终端聚合控制机制,并且提出解决UST频繁切换所引起的性能瓶颈的快速判决算法.     

Pervaporative transport mechanisms in phosphonium ionic liquid-based supported liquid membrane and its stability with actual fermentation broth feed

The pervaporative transport interactions between trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide ionic liquid-based membrane and the components of ABE fermentation broth were elucidated in this study. Acetone has a suggested viscosity decreasing effect on the ionic liquid and exhibited coupling effect with 1-butanol. Temperature increase consistently caused increase on 1-butanol permeance. The presence of acetic and butyric acids has no observed effect on 1-butanol and water permeation. No permeation of ethanol and acetic acid was noted, while butyric acid permeation can be suppressed by pH control. The membrane was proven stable in separating 1-butanol from actual fermentation broth for long period of time.     

苦参提取液及其与多菌灵混配对黄瓜灰霉病菌的毒力测定

室内采用生长速率法测定了苦参水提取液和酸碱提取液及其与多菌灵不同混配组合对黄瓜灰霉病菌的毒力。结果表明,苦参水提取液对黄瓜灰霉病菌菌丝生长的抑制效果优于苦参酸碱提取液,EC50分别为110.00μg/mL和280.60μg/mL。多菌灵与苦参水提取液混剂配比为10﹕1时,对黄瓜灰霉病菌菌丝生长的抑制具有明显的增效作用,EC50为0.03μg/mL,共毒系数为278.3。