定向

The itrack system provides accurate walkover guidance information for horizontal directional drilling machines .

领航者系统为水平定向钻机提供准确的导向。

In this dissertation, InGaAs/InGaAsP/InP MQW microdisk laser and its characterization were presented. Some conclusions are as following: the characteristics of lasing threshold was discussed by using rate equation. The dependent relations between threshold and cavity volume, spontaneous emission coupling efficiency β were investigated. The whispering gallery mode and spontaneous emission in a microdisk geometry were then studied. Almost all spontaneous emission was coupled into the lowest order TE mode when the normalized thickness of photonics well was between 0.15 and 0.5. The design principle and device process of InGaAs/InGaAsP/InP MQW microdisk laser were presented. The microdisk lasers with the diameter of 8μm, 4. 5μm and 2μm were succesfully fabricated by using etching techniques. The pulse lasing thresholds for the microdisk with the diameter of 8μm and 4. 5μm were 170μW and 15μW, a record results compared with the published in the literature. The cw lasing threshold for a 2-μm-diameter microdisk was only a few μW. We haven't found similar report up to now. To solve the problem of directional output in a microdisk laser, the power coupling efficiency in a double disk geometry was investigated with the theory of waveguide mode couple. A new structure of electrically pumped microdisk laser with output waveguide was designed, making a foundation for the practical use of microdisk laser.

本文主要研究InGaAs/InGaAsP/InP多量子阱半导体碟型激光器的研制和特性表征，并取得如下结果：利用速率方程理论讨论了激光器激射阈值的特性，分析了阈值与腔体积和自发发射耦合系数β之间的关系；讨论了微碟光子阱结构中的自发发射特性和微碟中WGM模式特性；光子阱结构在其归一化厚度在0.15-0.5之间时，几乎全部自发发射进入到最低阶TE模式中；研究了InGaAs/InGaAsP/InP多量子阱微碟激光器的结构设计原理和器件的制备工艺；利用刻蚀方法成功制备出直径分别为8μm、4.5μm、2μm的碟型微腔激光器；直径8μm和4.5μm的微碟脉冲光泵浦激射阈值分别为170μW、15μW，是目前所见文献报导中比较低的；直径2μm的微碟连续光泵浦激射阈值仅几μW，目前尚未见到达到类似结果的研究报导；为解决微碟激光器激射光定向引出的问题，通过波导耦合模理论分析了双层碟之间功率耦合效率；据此设计了新型带耦合输出波导的电泵浦微腔激光器，为进一步研制可实用的电泵浦微腔激光器打下基础。

Methods The whole-length X gene was directly cloned to pcDNA3.1 vector. The recombinant vector (pcDNA3.1-X) was transfected into HEPG2 cells after selection with hygromycin, steady clones (HEPG2-X cells) were obtained. The expression of RhoC protein was analysed with immunohistochemical stain.

用定向克隆的方法构建X基因的真核表达载体pcDNA3.1-X，脂质体转染HEPG2细胞；潮霉素选择培养稳定表达X基因的HEPG2-X细胞；免疫组化鉴定HEPG2-X细胞RhoC蛋白表达。

METHODS: MyoD cDNA fragments were extracted from plasmids pEMSV-MyoD with polymerase chain reaction, and PCR was used to clone the whole-length gene of MyoD. After adding CACC sequence at 5' end, MyoD gene was cloned by orient topology into transfer ventor, pENTR/D-TOPO. Objective gene was transferred into adenoviral expression vector DNA via pENTR/D-TOPO vector. The recombinant adenoviral vectors transfected into HEK293A cells by using lipofectamine were packaged and amplified.

从pEMSV-MyoD质粒上用聚合酶链反应法扩增出MyoD cDNA片段，再通过聚合酶链反应使MyoD基因加上CACC序列接头，经过定向拓扑克隆使目的基因连接到转移载体上，再通过LR酶促反应，将目的基因转移到腺病毒表达载体DNA上，获得MyoD基因重组的腺病毒DNA，用脂质体转染法转染HEK293A细胞，包装扩增出MyoD基因重组的腺病毒。

We think that the mechanism of directed forgetting should be rehearsal and retrieval by way of word method.

我们认为，在单字呈现的方式下，定向遗忘的机制应该是复述和提取抑制。

Up to now, there is no report on self-orientation of MFI-type zeolite.

本发明是一种MFI沸石晶体择优定向生长的方法。

In addition, we have developed a simple and efficient computational method for design of zeolite frameworks with specified pore structures.

此外，我们还开发了一种简单、高效的计算机方法来定向设计具有指定孔道结构的分子筛骨架。

Firstly, the object's position and orientation are determined by a vision system, the orientation of an object is the angle between the X-axis of the coordinate system and the axis of the least moment of inertia of the object in this system, and the position value is the vector between the coordinate zero point and the object's centre of gravity.

第一步利用视觉转动惯量法对任意放置在CMM工作台上的工件状态进行定位和定向；第二步利用测量离散点和模型投影点之间的关系，求取工件坐标系和设计坐标系之间准确的转换关系。

In this paper, two high temperature gradient directional solidification apparatus with liquid metal cooling and electron-beam floating zone melting were used.

本文采用LMC和电子束区熔两种高温度梯度定向凝固装置，研究合金成分及工艺参数对初生相析出行为的影响，优化了自生复合材料的制备工艺。

In this investigation fragments of Acropora pulchra were used in a semiprotected nursery in southern Taiwan between 1996 and 1998 to test, in situ, the possible effects of different factors on the generation of new branches and the initial skeletal extension rates of transplants.

在调查研究的美丽轴孔珊瑚是以半保护的养殖牧场在1996年到1998年於南台湾做测试，在那里，有可能会影响移植片段中的新分叉生长和骨骼生长速率之不同因子；这些变因在此研究中有片段的来源及长度、它们新的定向、存在的组织伤害和片段的位置。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。