谈谈消费品进入消费环节后的再交换

马克思关于社会再生产理论表明:任何社会的再生产过程,都是生产、分配、交换和消费四个环节紧密联系在一起的有机统一体。社会再生产过程,总是从生产开始,经过分配和交换,归于消费。生产、分配、交换和消费四个环节的运动是周而复始的。这种运动的结果,使社会再生产螺旋式上升,

超轻量级的交换再交叉运算认证协议

在分析张兴等[18]协议存在隐私泄露基础之上,设计一种认证协议。协议在确保隐私信息安全前提下,采用交换再交叉运算对发送信息加密;交换再交叉运算基于按位运算实现,在确保隐私信息安全的同时,可满足降低计算量的要求;为能够抵抗假冒攻击,消息接收者先对消息来源方进行真伪识别,仅在通过后才能进入后续操作。对协议进行基于GNY逻辑形式化分析,推理出协议的正确性及满足用户安全所需;将协议与其他协议做性能比较,协议具备计算量小的特征。

LNG接收站BOG处理工艺优化——以青岛LNG接收站为例

蒸发气(Boil Off Gas,缩写为BOG)的处理是LNG接收站必须考虑的关键问题之一,关系着LNG接收站的能耗及安全、平稳运行。为此,介绍了LNG接收站BOG处理的4种工艺:①BOG直接压缩工艺;②BOG再冷凝液化工艺;③BOG间接热交换再液化工艺;④蓄冷式BOG再液化工艺。运用HYSYS软件建立了采用不同BOG处理工艺的LNG接收站模型,对比了目前主要采用的BOG直接压缩工艺和再冷凝液化工艺在工艺流程及能耗方面的差异,并分析了外输量、外输压力及再冷凝器压力对BOG处理工艺节能效果的影响,在此基础上提出了BOG再冷凝液化工艺的改进措施——BOG进入再冷凝器前进行预冷,可比原工艺节约18.2%的能耗。同时还针对青岛LNG接收站提出了BOG再冷凝液化及直接压缩工艺混合使用的优化运行方案,可使进入再冷凝器的LNG流量保持恒定,没被冷凝的BOG经过高压压缩机提压到外输压力,与完成气化的LNG混合后外输,可避免BOG进入火炬系统而造成的能源浪费,同时减小再冷凝器入口流量的波动,使装置运行更稳定、更经济。

改进的无后端数据库的RFID认证协议

对文献[11]协议进行安全性分析,给出一个改进的无后端数据库的认证协议。为抵抗攻击者暴力破解攻击,所有通信消息加密再传送,且加密过程中全部混入随机数;协议为减少系统整体的计算量,采用基于位运算实现的交叉再交换运算对信息加密,加密算法实现过程中根据加密信息自身汉明重量的不同进行相对应的操作。对协议进行安全性和性能分析,结果表明协议在满足较高安全性的同时还可以适用于现有的低成本系统中。

养颜安神的安眠气功

本功法具有美容安神的作用,可治疗失眠、经前期精神紧张症、月经不调、闭经等病症。 1.小周天安眠法 仰卧床上,头、躯体、腿自然平放,两手互搭、手心向下,放于丹田上。由鼻深吸一口气,似乎用气充满全身,尔后用口缓缓呼出。随着呼气,意念从头至脚渐渐松静下来,如浮于云雾之中。

Support Effects on Thiophene Hydrodesulfurization over Co-Mo-Ni/Al_2O_3 and Co-Mo-Ni/TiO_2-Al_2O_3 Catalysts

A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization （in moderate conditions：200 ＆#176;C, 12 h） of red liquor solids, a by-product of paper-making process. The prepared sulfonated cata-lyst （SC） had aromatic structure, composed of carbon enriched inner core, and oxygen-containing （SO3H, COOH, OH） groups enriched surface. The SO3H, COOH, OH groups amounted to 0.74 mmol·g^-1, 0.78 mmol·g^-1, 2.18 mmol·g^-1, respectively. The fresh SC showed much higher catalytic activity than that of the traditional solid acid catalysts （strong-acid 732 cation exchange resin, hydrogen type zeolite socony mobile-five （HZSM-5）, sulfated zir-conia） in esterification of oleic acid. SC was deactivated during the reactions, through the mechanisms of leaching of sulfonated species and formation of sulfonate esters. Two regeneration methods were developed, and the catalytic activity can be mostly regenerated by regeneration Method 1 and be fully regenerated by regeneration Method 2, respectively.

Minimization of the Flowrate of Fresh Water and Corresponding Regenerated Water in Water-using System with Regeneration Reuse

A sequential three-step programming method is proposed for determining the minimum flowrate of fresh water and corresponding regenerated water in water-using system of single contaminant with regeneration reuse. In step 1, a programming with the objective of min fws is used to determine the minimum flowrate of fresh water, in which the mathematical representation is a mixed integer nonlinear programming (MINLP1). Then under the same constraints with step 1, a programming with the objective of min freg in step 2 and a programming with the objective of min Cr in step 3 are subsequently used to determine the minimum flowrate of regenerated water and the minimum inlet concentration to regeneration process corresponding to the minimum flowrate of fresh water based on step 1. The method is easy to apply because we only need to change the objective function but keep the constraints constant to go along the following steps after step 1. In addition, the relationship between the fresh water flowrate required, fws and inlet concentration to regeneration process, Cr, is investigated. It is found that there exist three relationships between fws and Cr, which indicate three possibilities for C\>: below the pinch, above the pinch or at the pinch. Therefore, a new conclusion is drawn, which differs from that 'regeneration of water at pinch minimizes fresh water flowrate' derived in literature and indicates that in some cases, regeneration at other point also minimizes fresh water flowrate.

One Step Preparation of Sulfonated Solid Catalyst and Its Effect in Esterification Reaction

A carbon-based sulfonated catalyst was prepared by direct sulfonation and carbonization （in moderate conditions：200 ＆#176;C, 12 h） of red liquor solids, a by-product of paper-making process. The prepared sulfonated cata-lyst （SC） had aromatic structure, composed of carbon enriched inner core, and oxygen-containing （SO3H, COOH, OH） groups enriched surface. The SO3H, COOH, OH groups amounted to 0.74 mmol·g^-1, 0.78 mmol·g^-1, 2.18 mmol·g^-1, respectively. The fresh SC showed much higher catalytic activity than that of the traditional solid acid catalysts （strong^-acid 732 cation exchange resin, hydrogen type zeolite socony mobile-five （HZSM-5）, sulfated zir-conia） in esterification of oleic acid. SC was deactivated during the reactions, through the mechanisms of leaching of sulfonated species and formation of sulfonate esters. Two regeneration methods were developed, and the catalytic activity can be mostly regenerated by regeneration Method 1 and be fully regenerated by regeneration Method 2, respectively.

STUDY ON CONTINUOUS ELECTROREGENERATION OF ION EXCHANGE RESIN

In this Paper, the continuous electroregeneration of ion exchange resin is investegated. The mixed resin is inserted between a canon exchange membrane and an auto n exchange membrane. The effuent water of fresh water room meets the demand for power plant on water treatment. The B_2 that is the cumulative formation constant of the metal complexes of resin is very differente with or without electric fied. It indicates that the dissociation degree of metal complexes of resin is greater hath electric field than that without electric field.

A Theoretical Dynamic Analysis of a Regenerative Heat Exchanger Assembly in a Fluctuating Flow Regime

A fluctuating flow was used to investigate the thermo-fluid characteristic of a regenerative heat exchanger assembly designed, modelled, built and constructed for the used in Stifling engines applications. Vibration of the regenerative heat exchanger assembly was a problem to deal with during the experimental investigation. Hence, a dynamic analysis of the regenerative heat exchanger assembly was undertaken. The main sources of excitation in vibrations of the regenerative heat exchanger assembly were investigated and calculated based initially on the empirical correlations provided in the literature. Thereafter, a mathematical model of the regenerative heat exchanger assembly was developed based on the energy equations for each moving part of the assembly. The kinetic and potential energy equations were formulated for each moving part of the regenerative heat exchanger assembly. From the kinetic and potential equations, the Lag, range operator was defined, and then the Lagrange formulations were used to derive the differential equations representing the dynamic behavior of each moving part of the assembly. The differential equations were integrated to determine the system natural frequencies. These were then compared to the frequency on excitation in vibrations in order to predict the regenerative heat exchanger working conditions despite the existence of vibration in the system.