不同条件下的曲柄摇杆机构设计

将图解原理解析化,完成不同条件下满足设计参数的曲柄摇杆机构各构件尺寸确定,整个过程借助计算机辅助设计。精确、实用。     

承压式氨分解器及其应用前景

传统的氨分解器产气压力均低于0．1MPa，本文介绍一种产气压力为0．5MPa的氨分解器，并对其承压式的结构特点及原理进行了较为详细的介绍以及列举了该装置的应用实例。     

Polly Two : A New Algebraic Polynomial-based Public-Key Scheme

Since Fellows and Koblitz introduced the generic combinatorially algebraic public-key cryptosystem Polly Cracker in 1993, the question whether there exist secure and efficient instances of Polly Cracker remains unsettled. Namely, many of these schemes succumb to the Linear-Algebra Attacks by D. Naccache et al. and Lenstra. In this paper I present a public-key cryptoscheme Polly Two that is efficient and in some way a modified Polly-Cracker instance, but comprises techniques defending the linear-algebra attacks.     

乙烯裂解炉辐射盘管的设计

详细介绍了裂解炉辐射盘管设计的选材、强度计算、直管段和管件几何尺寸的确定及焊接坡口型式。     

Modeling and Characterization of Air Emissions from Laboratory and Industrial Fluidized Beds

A fluidized bed model using several elutriation correlations was developed and tested against an operating fluidized bed used in a Fluidized Catalytic Cracker Unit (FCCU) and a 1:8.5 scale laboratory system. It was found that there was little variation between the emission rates predicted using different elutriation correlations, although the newly developed equations were slightly more accurate for the laboratory‐scale system. Although total emission rates were predicted with reasonable accuracy, the actual volatility and fluctuations seen in real fluidized beds emissions were not predicted. When the model was used to predict particle emission from the industrial FCCU, they preformed poorly, grossly overestimating the actual levels. It was determined that the attrition terms used in emission modeling were inappropriate and that the model preformed better without them, but still overestimated the actual emissions. This overestimation was greater in the industrial system compared with the smaller laboratory system. It was also found that the older elutriation terms were better for predicting industrial emissions compared with those of the smaller scale units.     

Nutritional and storage stability of wheat-based crackers incorporated with brown rice flour and carboxymethyl cellulose (CMC)

A study was conducted to develop brown rice flour (BRF) incorporated wheat-based crackers. Central composite rotatable design with three independent variables – BRF (10–40%), carboxymethyl cellulose (CMC) (1–3%), and shortening (5–12%) – produced 20 different combinations. Response surface methodology was used to study the effect of different levels of BRF, CMC, and shortenings on product characteristics like spread ratio, volume index, density, width, thickness, and puffiness. All the three independent variables significantly (p < 0.05) affected the product characteristics. However, BRF had more pronounced effect on product characteristics than other two independent variables. The optimum level of ingredients obtained by numerical optimization for development of crackers was – BRF to wheat flour ratio (10:90), CMC (1.8%), and shortening (5%). The optimized product packed in cellophane bags was found shelf stable for a period of 3 months under ambient conditions. The present study, therefore, confirms the feasibility of BRF incorporation (10%) in development of wheat-based crackers.     

Lattice Polly Cracker cryptosystems

Using Gröbner bases for the construction of public key cryptosystems has been often attempted, but has always failed.We review the reason for these failures, and show that only ideals generated by binomials may give a successful cryptosystem.As a consequence, we concentrate on binomial ideals that correspond to Euclidean lattices. We show how to build a cryptosystem based on lattice ideals and their Gröbner bases, and, after breaking a simple variant, we construct a more elaborate one. In this variant the trapdoor information consists in a “small” change of coordinates that allows one to recover a “fat” Gröbner basis. While finding a change of coordinates giving a fat Gröbner basis is a relatively easy problem, finding a small one seems to be a hard optimization problem.This paper develops the details and proofs related to computer algebra, the cryptographic details related to security, the comparison with other lattice cryptosystems and discusses the implementation.     

石脑油裂解装置建模与仿真技术

裂解装置提供了石化行业大部分基础原料，石脑油是目前国内外重要的裂解原料。对石脑油裂解反应过程、结焦过程和裂解炉辐射段的建模与仿真进行了综述：目前对分子动力学研究较多，用于离线仿真能够获得较好的效果，但在线应用不多；自由基动力学模型则是深入研究石脑油裂解过程本质的必然途径，在实际应用中越来越显示出其优越性。     

Inactivation of Salmonella enterica serovar Typhimurium and Escherichia coli O157:H7 in peanut butter cracker sandwiches by radio-frequency heating

A multistate outbreak of Salmonella enterica serovar Typhimurium recently occurred in the USA, which was traced back to various food products made with contaminated peanut butter. This study was conducted to investigate the efficacy of radio-frequency (RF) heating to inactivate S. Typhimurium and Escherichia coli O157:H7 in peanut butter cracker sandwiches using creamy and chunky commercial peanut butter and to determine the effect on quality by measuring color changes and sensory evaluation. Samples were treated for a maximum time of 90 s in a 27.12 MHz RF heating system. Samples were prepared in the form of peanut butter cracker sandwiches and placed in the middle of two parallel-plate electrodes. After 90 s of RF treatment, the log reductions of S. Typhimurium and E. coli O157:H7 were 4.29 and 4.39 log CFU/g, respectively, in creamy peanut butter. RF treatment of chunky peanut butter for 90 s also significantly (P < 0.05) reduced levels of S. Typhimurium and E. coli O157:H7 by 4.55 log CFU/g and 5.32 log CFU/g. Color values and sensory characteristics of the RF treated peanut butter and crackers were not significantly (P > 0.05) different from the control. These results suggest that RF heating can be applied to control pathogens in peanut butter products without affecting quality.     

烟花爆竹生产事故分析及防爆安全技术管理

烟花爆竹行业火灾爆炸事故不断发生,本文分析了此类事故发生的一般特点,并探讨了针对性的防火防爆安全技术与管理措施.