等环的

Hydrogen peroxide(H_2O_2)was used as oxidant,oxalic acid as complexing agent and tungstic acid (H_2WO_4)as catalyst.

研究了以环戊烯为原料、草酸为有机络合剂、H2O2为氧化剂，在催化剂钨酸(H2WO4)的作用下一步合成戊二酸的绿色新过程，考察了氧化剂的含量、反应物配比、催化剂用量、反应温度、反应时间等对反应的影响。

to overcome some disadvantages of low precision,slow dynamic response,unconvenience parameter adjust existing in high-power ultrasonic power supply,it applies intelligent control composed of 8089 microcontroller is proposed.the article introduces the modulation principle of spwm,the composition of high-power ultrasonic power system applying the single chip computer to realize the soft of phase lock loop,the mechanism of work and the software thought.it realizes the low loss,high power factor and the whole performance of the circuit is developed.

摘 要：针对目前大功率超声波电源采用模拟控制电路存在精度低、动态响应慢、参数整定不方便等缺点，采用单片机8089组成智能控制的超声波电源系统。提出了基于spwm技术的双闭环控制策略和应用单片机实现软锁相的工作原理和软件思想，使整个超声波电源实现了低损耗、高功率因数，优化了电路的整体性能。

These porblems are: legislation on city plan is deficient, causing unavoidable water pollution under many circumstances; there is lack of effective control of the two major pollutants:industrial sewage and daily sewage; the construction of relative organs is unable to meet the need of environmental protection; the underground water isnt under complete protection;control on other pollutants is unsufficient;local legislation is banal.

具体表现为环评制度、清洁生产制度等存在弊端，无法真正实现对工业废水的源头控制；对生活污水的立法仅限于末端治理，有关节约用水的立法空白较多；现有的城市污水处理系统由于缺乏法律的保障，从设置到运转状况均不能令人乐观；③城市水污染监管体制亦存在漏洞；④对地下水保护不力；⑤对其他污染源控制漏洞较多；⑥地方立法缺乏特色。

The filtering core is round column and welded with top and bottom covers bye anti-corrosive steel bar in wedgy section.The distance between every steel bar will be same and according to the filtering requirement.Several hoops are welded outside.So this filtering core has enough anti-deformed strength as well as high accuracy for filtering.

每个过滤元件呈圆筒状，采用楔形截面的耐蚀钢丝条与上下封焊接，每根丝条的间隔按过滤精度的要求等间隙均匀布置，在长度方向还焊有多道环箍，该滤芯不仅具有足够的搞变形的刚度和强度，而且可以严格保证过滤精度。

The change for substitute group on chlorin ring of chlorophyll-a derivative and the effect on their visible spectra is discussed and summarized according to relation of electron effect and substituted position of different groups with conjugated region.

根据不同取代基的电子效应、取代位置与分子共轭区域的联系，提出二氮杂轮烯和四氮杂轮烯组成的非等原子芳香体系结构，总结了卟吩大环上的化学结构变化对其可见光谱的影响。

To solve those problems in extended reach wells and horizontal multibranch wells and ease the "bottleneck" of domestic pointthebit of rotary steerable drilling technology, combining theory with practice, we summarize the rotary steerable drilling technology at home and abroad, introduce two typical and popular bottom hole closed loop rotary steerable drilling tools, namely MRST and GeoPilot.

为解决在钻大位移井、水平分支井等复杂结构井时出现的种种难题以及国内指向式旋转导向钻井技术的&瓶颈&问题，将理论与实践相结合，对旋转导向钻井技术的国内外研究现状做了分析；介绍了目前国内外运用比较广泛且典型的推靠式MRST和指向式GeoPilot井下闭环旋转导向钻井工具。

This paper chooses 2000 stochastic retailing stores whose acreages all exceed 40km2 in the three circles of Wuhan city,after the analysis of spatial difference on acreages,number,population density,and manage forms,and makes a conclusion that the retailing spatial structure of Wuhan city has taken on figure of ring shape with hierarchy wholly and frame of centralization-diffusion and enchasing partially; Finally,the whole paper probes into the change mechanism and trends of retailing spatial structure.

随机抽取武汉市中环线内2000个营业面积大于40m2的零售商业网点，基于统计资料、实地调查，运用GIS空间分析技术，划分环带与格网提取武汉市零售业网点密度、服务人口、营业面积、业态分布、商品特色等空间分布数据，分析零售业网点密度分布的空间特征，得出武汉市零售业在空间结构上表现出整体的等级圈层结构，局部的空间聚合扩散结构和&逆发散特征&——镶嵌结构；最后对其变动的动力机制和演变趋势进行了初步探讨。

At the same time, the conformational changes will lead to the changes in thermodynamic properties such as average energy and free energy. Besides, scatting functions are also obtained for star polymer chains with different branches respectively.

同时，高分子链构象在拉伸过程中的变化会引起热力学性质的变化，如平均能量、自由能等。g因子能够大致描绘出环型或星型高分子链与线型高分子链的结构相似程度，模拟的结果显示：它们在拉伸过程中都是减小的。

This review focuses on newly developed strategies for miRNA quantification, and elucidates in detail the probe-hybridization based methods including Northern blotting, microarray, gold nanoparticle labelling, and splinted ligation with radioactive labels. The amplification-based methods including quantitative PCR, rolling cycle amplification, invader assay, and the next generation sequencing methods were also discussed. The advantages and disadvantages of these methods were compared.

文章系统地介绍了最新发展的microRNA定量检测方法，详细阐述了基于探针杂交技术的Northern blotting法、微阵列芯片法、纳米金标记法、桥连同位素标记法，以及基于扩增技术的定量PCR检测法、滚环扩增法、引物入侵法和新一代大规模高通量测序法等，并对这些方法的优缺点进行了分析比较。

The elastic contact between steel liner and surrounding concrete as well as the softening of concrete and damage under tension were considered. The analysis results of concrete damage in different parts surrounding the spiral case and vertical displacement of turbine and generator foundations were obtained. In addition, based on the damage analysis of concrete the flexibility check for stay ring was also carried out.

数值计算模型考虑了钢衬和外围混凝土之间的摩擦接触、混凝土材料的拉伸软化和损伤特性，对外围混凝土的损伤指标及分布、各钢部件应力、结构位移等进行了分析研究，并在蜗壳外围混凝土发生损伤的情况下对座环柔度进行了复核。

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。