城市原生污水源热泵经济性分析

分析了城市原生污水源的特点及其热泵系统的优缺点。以哈尔滨地区的工程为例,对城市原生污水源热泵、天然气直燃热泵机组、燃煤锅炉加电制冷冷水机组进行了经济性、环保性比较。结果表明城市原生污水源热泵系统优于另两个系统。     

网络安全背景下加强班级思想道德建设策略

伴随网络环境的不断发展,网络安全成为当下网络教育的重要教学方向.网络环境的不断发展,使得网络安全难以保障,这也就对当下学生思想道德建设产生了一定的影响.班级思想道德建设有利于培养学生正确的道德思想理念,对此教师要重视此项教育教学工作的开展,另外网络作为学生生活的必需品,教师要加强对学生网络安全思想的引导,以培养学生对网...     

基于椭圆曲线密码的RFID安全协议

为了能够解决RFID在用户安全、隐私等问题方面的安全隐患,提出了一种基于椭圆曲线密码的RFID安全协议.在椭圆曲线离散对数问题难解的基础上,与其它公钥密码体制相比,该协议的安全性能更高、密码长度更短且计算量更低.该协议运用基于椭圆曲线的DH密钥交换协议ECDH(elliptic curve Diffie-Hellman)与基于嵌入明文的加密方案,实现了保护RFID标签与读写器之间的数据交换;同时,通过对该协议的安全性分析以及与其它采用对称密钥体系的RFID协议的比较表明,该协议能够满足RFID系统的安全性要求.     

Experimental study on thermal resistance of fouling in heat exchangers of sewage source heat pumps

To investigate the formation of fouling in sewage heat exchangers,a model of thermal resistance with time is developed based on the experiments in a practical engineering site. And this model is asymptotic exponential function. According to the characteristic of sewage heat exchangers,the effective thermal resistance and effective coefficient of heat transmission during the formation of fouling are defined. A model for pressure loss of fouling of asymptotic distribution is presented based on the model of thermal resistance of fouling. And the maximum absolute margin of error of the fouling thermal resistance is smaller than the typical allowable error range. The maximum relative error of the heat transfer coefficient is 12% . These can meet the requirements of engineering. The results of experiments provide a basis for further study and application of swage heat exchangers.