Points out that some designers only use empirical methods in determining the inner diameter of pipeline , calculating system resistance and selecting the rated flow and rated head of circulating pumps in water systems 摘要指出目前一些设计人员在设计空调水系统时，仅根据经验值估算管道内径、计算管路阻力和选配系统循环水泵的流量和扬程。
The loss of individual species in ecosystems , such as frogs in wetlands or ferns in a forest , can certainly affect the ways in which those systems work together to cycle essential nutrients and water and process energy 在生态系统中个别物种的消失，像沼泽地的青蛙和森林中的藻类植物，必然能影响那些系统循环必要的营养、水分和能量过程的共同运行的方式。
By citing distribution piping loss curve , analyses the two commonly used control methods of constant pump head and constant remote circuit differential pressure and considers that control with a constant remote circuit differential pressure is the better 通过提出输配管压损曲线概念，从理论上分析了计量供热变流量系统循环水泵常用的恒扬程控制和恒定最不利环路压降控制两种方案，认为恒定最不利用户资用压力方案节能效果较好。
Finally , authors attempt to solve the optimum model from the viewpoint of integrated urban land - use , transportation system planning and propose a solving method which can realize the circular relationship between urban land - use pattern and transportation system 结合城市交通规划模型，提出了能体现土地利用与交通系统循环反馈关系的求解方法，从交通效率最大化或局部最大化的角度，对土地利用交通系统的一体化规划进行了有益的尝试。
On the basis of simulation and experiment , the dynamic characteristic of frosting and defrosting of ashp is studied . a set of simple equations is put forward to model the reverse cycle procedure of defrost and is put into the practice to simulate the dynamic characteristics of frosting and defrosting of ashp 在仿真模型研究中，提出了一个简单的可以用来模拟四通阀换向后系统高低压平衡和系统循环重新建立的过程，并将这一模型应用到机组动态特性研究。
The geographical point of soil phosphorus equilibrium refers to some quantitative characters of soil phosphorus system when its cycle becomes steady relatively in certain geographical , biological and climatic backgrounds . its index and seeking method are determined differently in different studies 土壤磷素地理平衡点指在特定的地理生物气候背景下，土壤磷素系统循环达到相对稳定平衡时的量化指标的数量水平，它的指标选取和求取方法应根据研究目的需要来确定。
The paper especially introduces the reconstruction of the performance management system of huafang corporation . in its analysis of the case of huafang corporation the paper elaborates and analyses the concepts , fundamental aims , system circulation , actual operation of the performance management as well as the reasons and the significance of adopting this method , hoping to find out a scientific , efficient and practical performance management system so as to put the corporation onto the track toward high efficiency and healthy development 案例的分析部分针对华房公司绩效管理存在的问题进行分析，同时对绩效管理的含义、目的及意义、系统循环、实际等作了详细的阐述和分析，希望通过分析帮助华房公司探索出一套科学、有效的绩效管理体系，通过员工绩效的持续改进，达到公司的业绩不断提升的目的，使公司的经营管理步入高效运作、健康发展的轨道。
Zlpg series hot water canned motor pipeline mounted pumps are used to handle soft water below 160 and not containing solid particles , suitable for hot water cyclic transportation in the areas of energy resources , metallurgy , chemicals , textile , papermaking , hotels , restaurants , bathrooms and boilers , as well as for circulation of urban heating system Zlpg系列屏蔽式管道泵热水型主要供输送温度不超过160不含固体颗粒的软水之用，适用于能源、冶金、化工、纺织、造纸以及宾馆、饭店、浴室、锅炉热水增压循环输送及城市采暖系统循环场合。
Part 3 : the paper set out from big system and coordination view , use the systematic dynamics method to analyse all - sidedly that the city expands the relation with various kinds of ecological factors , and natural factor discern mode of city develop , point out city ecological problems are production by improper use the environment ecological factor during city expand , it cause the problems production , such as the function of natural system disappearance or lose efficiency ; systematic circulation obstruct , material energy transform efficiency being low , and so on 第三部分：从大系统大协调观出发，运用系统动力学方法全面分析城市扩展与各种生态因子的因果关系，及城市发展的自然因子识别模式，指出城市生态问题的产生是由于城市扩展对环境生态因子的不当使用，导致自然系统功能的缺失或失效，系统循环受阻，物质能量转化效率低下等问题的产生。
The authors first apply basic theory of equivalent heat drop on the common circulation heat calculating model for thermal system in supercritical pressure power unit with second reheat cycles and other kind of condensing steam turbine by mathematical derivation strictly , based on the normal energy balance and theory of equivalent heat drop , aiming at characteristics of thermal system in which there are outer steam coolers that high pressure heater and low pressure heater carry 摘要以常规热平衡方法和等效热降理论为基础，针对二次再热超临界机组热力系统高低压加热器均设置外置式蒸汽冷却器的特点，经过严格的数学推导，将等效热降理论应用于二次再热超临界机组热力系统循环吸热量计算的研究，并提出了适用于不同类型凝汽式机组的通用数学计算模型。
