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1.
一、引言 SD—400keV离子注入机是一种多用途离子注入机,它具有注入元素种类多、能量调节范围广、扫描面积大等特点,可以注入从质量数为1的氢离子直到质量数大于200的重离子;能量从50keV到400keV连续可调;具有垂直扫描和非垂直扫描两种功能。本机主要用于功能材料、固体材料改性和功能器件的研究以及离子与固体相互作用的基础研究等领域。  相似文献   

2.
注~(31)P~ 硅片损伤层的喇曼光谱术研究   总被引:1,自引:0,他引:1  
离子注入是一种制备半导体器件的重要工艺.离子注入会造成半导体材料晶格的损伤,从而引起材料光学性质的改变.随着注入剂量的增加,损伤区域不断扩大,以致形成非晶态层.制备半导体器件,通常必须对注入后的晶片进行热退火,以消除这种晶格损伤.因此,检测离子注入半导体中的晶格损伤具有重要的应用意义.检测离子注入后半导体中损伤层的方法已有多种,其中传统的方法包括背散射沟道方法和顺磁共振方法,在光学手段中包括反射率方法和椭圆偏振方法,1974年,法国的J.C.Bour-  相似文献   

3.
离子注入技术可使各种刀具、模具、机械零件表面硬度、耐磨性、耐腐蚀性、耐疲劳性大大提高。并具有其他表面处理方法所不能代替的特点。与渗碳、渗氮表面处理方法相比,离子注入没有高温工件变形、表面氧化、精度改变等优点。当前用离子注入使金属工件、工具表面改性,美、英、日等国已达到工业应用。  相似文献   

4.
建立了超高效液相色谱-四极杆-飞行时间质谱仪(UPLC-Q-Tof/MS)检测野樱莓冻干粉成分的方法.采用梯度洗脱的色谱分离方式,分别采集ESI正离子和ESI负离子两种模式下的质谱数据,并根据目标化合物特征离子的精确质量数、二级碎片信息等进行数据库匹配,在无标准品情况下利用Unify 1.7软件非靶向快速筛查野樱莓冻干粉的多酚类组分.结果表明,ESI正离子和ESI负离子模式下分别检测出60余种和200余种多酚类物质,且质量数偏差均在3mDa以内.  相似文献   

5.
在信号跟踪环节中,载波跟踪是关键部分,而载波跟踪的改进主要体现在载波环路滤波器的设计上.为了均衡载波同步的跟踪精度、环路带宽与快速同步3者之间的矛盾,提出了基于相位锁定检测量的自适应可变带宽的锁频环(FLL)与锁相环(PLL)相结合的跟踪方案,同时利用可控根法来完成数字环路滤波器参数的设计.由仿真结果得出可控根法可直接设计数字滤波器参数而不依赖模拟概念,同时基于自适应变带宽的锁频辅助锁相跟踪环路可以扩大锁定范围,适应更高动态,自适应变带宽可以在不影响锁定精度的条件下缩短锁定时间,达到快速同步.此方法可折中载波跟踪的各性能,达到平衡状态.  相似文献   

6.
微弱信号检测-数字相关技术的研究   总被引:3,自引:0,他引:3  
数字相关技术是众多微弱信号检测技术中能够使测量精度和自动化程度有很大提高的最佳技术。本文主要对数字相关锁定放大器的原理进行了比较和研究。  相似文献   

7.
针对传统遥感影像水体信息检测环节多、过程复杂的问题,本文提出一种基于归一化水体指数(NDWI)自约束的水体判别方法,该方法直接从影像中检测水体,能减少操作环节、提高检测速度,为水体应急监测提供快速响应的方法。通过对本方法与阈值法、分类法在不同数据中进行测试,结果显示:本方法对World View-2、Landsat8和Sentinel-2A影像水体检测的总体精度介于83. 87%~91. 53%,阈值法检测的总体精度介于85. 07%~94. 07%,支持向量机分类法检测的总体精度介于91. 91%~97. 70%;该方法对水体的检测精度不及阈值法和分类法高,但在具有较高检测精度的同时能明显简化操作,在水体监测应急响应中具有实际应用价值。  相似文献   

8.
提出一种改进的基于磁巴克豪森噪声(MBN)技术的无缝线路实际锁定轨温检测方法。该方法使用MBN技术检测钢轨温度应力,使用轨温计检测表面轨温,并采用最小二乘支持向量机(LS-SVM)算法建立线路的钢轨温度应力随钢轨表面轨温与实际锁定轨温差值变化的预测模型,最后将预测模型得到的温差和钢轨的表面轨温用于计算实际锁定轨温。通过对河北保定的一段无缝线路进行钢轨温度应力及表面轨温检测,证明该方法能提高检测的精度。  相似文献   

9.
由我校低能所李国辉副研究员主持,刘伊犁教授、姬成周副研究员和GaAs新器件课题组参加完成的国家自然科学基金项目“GaAsIC中的离子注入和白光快速退火技术”,近日通过了国家科委主持的鉴定.学部委员黄祖洽教授以及北京市技术研究院的有关同志参加了鉴定会.该成果研究了GaAs集成电路中离子注入的关健技术,提出了形成高质量离子注入层的技术条件,在材料与离子注入层特殊关系的研究中提出了新见解;应用形成的技术成果探讨了新型器件研制中的物理、器件、材料与工艺问题,并研究了有关的检测技术,对提高材  相似文献   

10.
基于视频图像处理的行人和非机动车数据采集技术   总被引:2,自引:0,他引:2  
在交通数据实时采集的诸多技术中,基于视频图像处理的方法不但能够克服人工采集方法精度低、可靠性差等缺陷,还能够解决传统的感应线圈检测、雷达检测和微波检测等方法无法检测非机动车和行人的问题.本文针对该问题设计和提出在混合交通情况下的视频交通数据采集系统,通过将视频图像处理技术和神经网络相结合,采集交通数据并识别和区分不同种类的交通对象.经过测试实验,效果比较理想.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

19.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

20.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

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