螺距比

The results indicate that the characters of twisted tubes are better than round tubes, and the heat transfer coefficient and power characters are increased with the diminishment of geometry sizes and the increase of fluid parameters.

实验结果表明，扭曲管比圆管的性能好，螺距和管径越小、水喷淋密度和风速越大，传热系数越高，但流动阻力同时增大，存在合适的螺距、管径、水喷淋密度和风速使蒸发式冷凝器综合性能最佳。

When end surface is neglected, the reflective energy will return to the filament efficiently if the filament is at the centre axis of the columniform lamp shell. 3 Compared with the straight tungsten filament that has a smooth surface, the helical one obtains higher absorbance which can achieve 0.6~0.7 under the actual screw pitch measurement.

当灯的管径为10 mm，而灯丝外径为1.5 mm时，节能可达12%到13%。2）对圆柱形灯外壳，在不考虑端面影响时，光源的灯丝若处于外壳的中心轴上，则反射的能量会有效地返回灯丝。3）螺旋结构的灯丝比表面光滑的直钨丝有更高的吸收率，灯丝绕成螺旋后在现行的螺距尺寸下吸收率能达到

Five different mixing chamber geometries are tested experimentally with the stoichiometric gasoline-compressed air at frequency of 6 Hz and the effect of screw-pitch and inner diameter ratio on the performances of PDE is investigated.

实验针对爆震频率为6Hz、当量比为1的汽油和压缩空气混合气，实验研究了脉冲爆震发动机模型混合室内5种不同扰流螺纹螺距内径比对其性能的影响。

But some problems of designing including failure model of soils, the design of shape of screw piles, the computation of ultimate load for single screw pile or screw pile group, the reasonable ratio of diameter of lamina to pitch of screws or the distance of laminas were seldom researched.

但目前对于极限荷载条件下螺旋桩基础的地基破坏模式、桩型设计、单桩和群桩极限承载力的计算，以及合理的螺距与叶片直径比等问题的研究尚少，有待进一步完善。

By analyzing and handling the experiments results, we obtained the rules of change of hydrodynamic characteristics of the cycloidal propeller in the pitch ratio varying from 0.2π to 0.75π and the steering angle varying from -90°to 90°, such that a foundation has been laid for using it in practice, and for setting up the theoretical calculation method of cycloidal propeller.

一、通过分析摆线推进器的工作原理，设计并加工了实验模型和实验装置，在哈尔滨工程大学船模水池对该模型进行实验，经过合理的理论分析和数据处理，获得了螺距比从0.2π到0.75π，方向角从-90°到90°范围内的水动力变化规律，为建立摆线推进器水动力性能理论计算方法和工程应用奠定了基础。

A maneuvering mathematical model for Controllable-Pitch Propeller ships with three degrees of freedom is established according to separate modeling theory. Based on Netherlands Ship Model Basin\'s open-water tests, CPP thrust coefficients and torque coefficients in four-quadrant with different pitch ratio of screw and different types of CPP are obtained by using Akima interpolation. Therefore, CPP thrusts and torques are obtained.

基于船舶操纵性分离建模理论，采用荷兰船模试验水池B系列螺旋桨的敞水试验结果，利用Akima插值获得了不同类型的调距桨在不同螺距比下的四象限推力系数和扭矩系数，求得调距桨的推力和扭矩，建立了调距桨船舶的平面运动数学模型。

Fancy gold-plated dangling earrings with facetted White Opal crystals.

花式镀金悬垂耳环与facetted白欧泊水晶。

This essay chooses the study aim from biology teachers in middle school in Shi Jiazhuang which tells us that most of the middle school biology teachers in Shi Jiazhuang have the"burnout", lower successfulness, individualize.

本文选取石家庄市初中生物教师作为研究对象，运用问卷调查的方法对石家庄市初中生物教师职业倦怠的现状进行调查，调查结果发现，石家庄市初中生物教师这一群体普遍存在职业倦怠，情感枯竭程度偏高，成就感偏低，去个性化程度最为严重。