优缺点

The paper describes in detail the four factors resulting in the corrosion of buried steel pipeline,that is environment,corrosion control effectiveness,material of pipe steel,and stress of pipeline,presents a total statistics on petroleum asphalt,coal-tar enemal,extruded polyethylene coating,PE tape,FBE,and multiple coating system and the individual percentage of theirs per years during 1990-1995,and points out that the selection of all kinds of coatings,being different behaviors,should be defermined according to the geological conditions and corrosive environments along pipeline route.

阐述了埋地钢质管道发生腐蚀的四个影响因素，即环境、腐蚀防护效果、钢管材质和制造工艺以及应力水平，统计了1990-1995年石油沥青、煤焦油瓷漆、挤塑聚乙烯、PE胶带、FBE、复合覆盖层的涂敷量，指出防腐覆盖层各有优缺点，应根据管道线路的地质条件、腐蚀环境等而定，目前应建立防腐层的综合评价方法以解决防腐覆盖层的设计问题，同时还应对钢管表面处理、现场补口加以重视，在采用高强薄壁钢材时应考虑壁厚要求。

The main matter of the third section is that two traditional power converter main circuit for four phase SRM are analyzed, optimized and synthesized, the paper gives the main circuit of new power converter for four phase SR motor.

第三部分为功率变换器的设计，在详细分析四相电机常用的两种主电路优缺点的基础上，给出了目前相对性价比最优的最少主开关主电路形式。

The paper verified the rationality and superiority for the long distance visual micrometer using on the numerical control machine by analyzing the relative merits of position detectors that commonly used like inductosyns, coders and rasters.

文章通过分析数控机床常用的位置检测装置（感应同步器、编码器、光栅）的优缺点，充分验证了视觉型长值千分尺应用与位置检测装置的合理性及优势。

The advantages and disadvantages of individual control approach of ragweeds were introduced in this article.

文章阐述了各项措施在豚草种群控制中的作用和优缺点。

The classification,main modes,scope of application,advantages and defects of city natural gas transmission and distribution network are compared,the principle for selecting gas transmission and distribution network is put forward,and the application of regulator box and PE pipe in a medium-pressure single stage system is discussed.

对城镇天然气输配管网分级、主要型式、适用范围、优缺点进行了比较，提出了燃气输配管网选择原则，探讨了调压柜和PE管在中压单级管网系统中的应用。

The Pipe Coupling of the Rotary Extrusion Type is schemed out finally after the inventor has analyzed and generalized the relative merits of the existing pipe couplings for a long time.

发明人经长期分析与归纳现有管道连接的优缺点，设计出了&旋压式管接头&。

The methods of chip-breaking in machining pipe thread were researched deeply, which are classified into two categories: the methods acting on tools and adding auxiliary devices for chip-breaking. The principle of work, the technical characteristics, the advantages and disadvantages, and so on were analyzed, compared and summarized, and the following research directions were also pointed out.

摘 要：深入研究了管螺纹加工的断屑方法，将目前管螺纹加工的断屑方法分为两大类——作用于刀具上的方法和增加断屑辅助装置的方法，并对各种方法的工作原理、技术特点及优缺点等进行了全面的分析、比较和总结，指出了管螺纹加工断屑方法仍然存在的问题和下一步的研究方向。

In this paper, the progress of microbial remediation for the pyrethroid pesticide waste in the environment was reviewed, its advantages and disadvantages of the microbial remediation was analysed.

本文综述了拟除虫菊酯农药微生物修复的研究进展，客观地分析了微生物修复的优缺点。

Ultimately, 25 articles were included. We arranged and analyzed material science characteristics, clinical application, advantages and disadvantages of bone plate.

共纳入25篇文献，从接骨钢板的材料学特征、临床应用及其优缺点方面加以整理和分析。

It provides useful probations for making use of prestressed concrete long span structure in high-rise buildings.

着重介绍了预应力混凝土框架体系在高层建筑中的应用，分析了各种方案的优缺点，对预应力框架梁的截面选择、次弯矩计算、预应力筋确定进行了详细的分析，为高层建筑采用大跨预应力结构提供了有益的探索

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。