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1.
线性双曲型方程新的TVD格式   总被引:3,自引:0,他引:3  
从双曲型方程的TVD条件出发,分析了Lax-Wendroff格式和Warming-Beam格式所存在的TVD区间,构造了空间三点和四点新的二阶TVD格式,使其在极值点也保持二阶精度。最后给出了新格式与传统TVD格式的结果的比较。  相似文献   

2.
1 Introduction  Recentlyopticaldisksabletostorealargequantityofinformationhavebeenusedascompactdisk (CD ) ,digitalversatiledisk(DVD) ,andtheirrecordableorrewritabletypes(suchasCD R ,CD RW ,DVD R ,andDVD RAM ) [1 ] .Anopticaldiskisakindofmultilayersystemdepositedona…  相似文献   

3.
多组分金属催化剂表面漫反射紫外可见光谱研究   总被引:4,自引:0,他引:4  
研究了二氧化碳加氢甲烷化二组分、三组分担载型金属催化剂表面漫反射紫外可见光谱(DRUVS)。根据DRUVS提供的信息,揭示了催化剂组分间相互作用结果对催化活性的影响;不同助剂量催化剂DRUVS特征强度与催化活性间定量关系也得到合理确定 。  相似文献   

4.
用新的紫外荧光光源对维生素D2的最佳光合成   总被引:3,自引:0,他引:3  
介绍了维生素D2(以下简称VD2)的光化反应与光照时间的关系,即由麦角甾醇为原料,在与之转化所需的最佳匹配光谱照射下,找到VD2的最佳光转化时间。结果表明,在283nm波长的紫外荧光光源照射下,其转化效果最佳。在此条件下麦角甾醇转化率随照射时间的增加而逐渐上升,但同时VD2的异构体(副产物)也随之增多,因此综合以上两种因素,从而可确定18 ̄21分钟是VD2光化反应的最佳时间段。  相似文献   

5.
用MOCVD技术在Al2O3衬底上外延GaN的光致发光研究   总被引:1,自引:1,他引:0  
高瑛  缪国庆 《光子学报》1997,26(11):982-986
本文通过变温和变激发强度的光致发光研究了用MOCVD在Al2O3上生长GaN单晶薄膜的带边发射,通过分峰拟合得到A,B,C,D四个谱峰,其中半峰宽分别为13.8meV,10.8meV,15.6meV,和50meV。A对应自由激子谱,B,C为两种束缚激子的跃迁,D与氧杂质谱有关。  相似文献   

6.
介绍了Windows环境下用VisualBasic(以下简称VB)开发AutoCAD的ADS应用程序的方法,并给出了应用实例。  相似文献   

7.
微波等离子体化学气相沉积金刚石膜   总被引:7,自引:0,他引:7  
胡海天  盛奕建 《物理》1996,25(11):688-696
微波等离子体化学气相沉积是制备金刚石膜的一个重要方法,能制备出表面光滑平整的大面积均匀金刚石膜,文章概述了MPCVD制备金刚石膜的情况,介绍了MPCVD制备金刚石膜装置的典型类型及其特点,在国内研制成功天线耦合石英钟罩式MPCVD制备金刚石膜装置,并在硅片上沉积出大面积均匀的优质金刚石膜。  相似文献   

8.
文内报告了150965MeVHD+离子微团簇经库仑爆炸在0°方向生成碎片H+和D+能谱的测量。获得HD+的最可几束缚能实测值为1148eV。较详细地讨论了HD+在高频离子源中的形成机理  相似文献   

9.
富力文 《物理》1989,18(3):167-168
本文叙述了电子回旋共振微波等离子体化学气相沉积(ECRPCVD)的工作原理、特点及其应用.ECRPCV D由放电室、淀积室、微波系统、磁场线圈、气路与真空系统组成.处于放电室的等离子体在磁场中做回旋运动,使电子的回旋运动频率与微波频率相同;处于回旋共振条件下的电子有效地吸收微波功率而获得高的能量,从而产生高活性和高密度的等离子体.电离度大于10%,电子密度为1013cm3.ECRPCVD可在低的气体流量、衬底不加热的情况下高速淀积高质量薄膜.以该技术淀积的Si,N4,SiO2薄膜可分别与高温CVD的Si3N4高温热氧化的SiO2相比拟.ECRPCVD淀积a-Si:H淀积速率为通常CVD的20倍,而性能与射频CVD淀积的a-Si:H相当.ECRPCVD 已成功用于淀积多种薄膜。  相似文献   

10.
祁守仁  李永平 《计算物理》1996,13(1):101-104
采用DV-Xα方法计算了ThMn12型合金中的理想结构YFe12给出了YFe12的电子结构和磁性。结果表明DV-Xα方法对磁性材料的研究有着广泛的实用性。  相似文献   

11.
王平 《光学技术》2000,26(2):160-162,164
由于在DVD产品中高科技成分含量高 ,所以DVD将成为多媒体时代的主要媒体。本文对在DVD产品设计上的新思维和关键技术进行了简单地介绍  相似文献   

12.
This paper presents an overview of the single-wafer optical processing techniques for integrated circuit fabrication with an emphasis on their applications to insulator growth. Rapid thermal growth of various thin homogeneous and heterogeneous dielectrics on silicon substrates including silicon dioxide, silicon nitride, nitrided oxides, and composition-tailored insulators will be described and some electronic device applications of the rapidly grown dielectrics will be examined. Multicycle rapid growth processes have been used for dielectric structural engineering and in-situ formation of thin layered insulators. The compositional depth profiles and the electrical characteristics of devices are controlled through the synthesis of an appropriate sequence of the wafer temperature-vs-time profiles and process gas cycles. The ongoing developments and future prospects of single-wafer rapid processing for advanced microelectronics manufacturing will also be discussed.  相似文献   

13.
《Comptes Rendus Physique》2013,14(4):352-365
The first generation of ground-based interferometric gravitational wave detectors, LIGO, GEO, and Virgo, have operated and taken data at their design sensitivities over the last few years. The data has been examined for the presence of gravitational wave signals. Presented here is a comprehensive review of the most significant results. The network of detectors is currently being upgraded and extended, providing a large likelihood for observations. These future prospects will also be discussed.  相似文献   

14.
With the rapid development of CD/DVD(compact disc/digital versatile disc)technology,the disc rotation speed and the information density have increased greatly to fulfil the demand of high informatiopn bit rate transfer,As one of the most important elements in a DVD pickup head,objective lens actuators are required to provide a more precise means to accurately follow the disc deviation.The design of the lens actuator becomes all the more important and critical.In order to give complete suggestion to the design of the lens actuator,we put forward the movement differnetial equations as a new theoretical means to analyse the characteristics of the lens actuator reliably and rigorously.Based on the theoretical analyses,many important and effective methods are propsed.A typical experiment verifies that the performance of our lens actuator head,which adopts these methods,can satisfy the high speed and high density requirement of DVD systems.  相似文献   

15.
用相移光阑延长高密度数字化视频光盘物镜焦深的研究   总被引:3,自引:2,他引:1  
王海凤  陈仲裕  干福熹 《光学学报》2001,21(10):260-1263
提出了一种利用优化了的三带相位型超分辨光阑来延长高密度数字化视频光盘(HD-DVD)的焦深的方法,同时使得聚焦光斑进一步减少,利用该器件可以将高密度数字化视频光盘的焦深延长到目前数字化视频光盘(DVD)的焦深长度,并且轴向强度分布也得到了优化。  相似文献   

16.
Wine has become a commodity of significant commercial value, and the demand for high quality wine by consumers has been increasing. Suitable analytical techniques are needed for its quality control. Ultraviolet, Visible, Near-infrared and infrared spectroscopy is by far one of the most important techniques for determining the wine quality, including its components and characterization. This review will overview the available most recent applications of spectroscopic techniques in the past decade for wine quality prediction and discrimination both quantitatively and qualitatively. The fundamental principles of these techniques will be introduced briefly, and some innovative setups/instrumentations will also be illustrated. At last the limitations and prospects of spectroscopic techniques for wine industry will be discussed.  相似文献   

17.
An innovative DVD pickup based on integrated dual-wavelength laser diode is developed. The dual-wavelength laser diode emits two lasers with different wavelengths. The laser with 650 nm wavelength is used for DVD, and the other with 780 nm wavelength is used for CD and CD-R/RW. Key techniques of this DVD pickup design are discussed. The feasibility of this scheme is proved by experimental results.  相似文献   

18.
通过改变裂纹的倾角、宽度和深度参数,模拟了赫兹型裂纹在不同参数下对光场调制能力的不同. 模拟发现,倾斜角度为20.9°到45°之间的裂纹危害最大,倾角大于45°小于48.2°的裂纹危害也十分大,而倾斜角度为45°时的裂纹危害最小. 对于30°倾角的赫兹型裂纹,一定范围内,赫兹型裂纹深度的增加会导致其光场调制增强能力呈二次方关系增加,但宽度的增加不会使其光场调制增强作用增加. 裂纹深度和宽度的增加可以用来近似裂纹的演化过程,所以裂纹的扩展导致了其光场调制能力的增加,进而导致损伤增长速率的加快,这和e指数损伤增长规律相符. 关键词: 损伤增长 亚表面缺陷 赫兹型裂纹 光场增强  相似文献   

19.
To improve the tracking servo performance, a novel signal waveform multi-level (SWML) read-only disc realized on the digital versatile disc (DVD) platform is presented. The characteristic of the differential phase detection (DPD) signal of the SWML read-only disc is analyzed both in theory and experiment. The amplitude of the DPD signal of the SWML read-only disc in an open tracking servo loop is about 2/3 of that of the DVD read-only disc. The uniformity and symmetry of the DPD signal of the SWML read-only disc are similar to those of the DVD read-only disc and better than the former multi-level run-length limited (ML-RLL) read-onlv disc.  相似文献   

20.
作为马约拉纳费米子的“凝聚态版本”,马约拉纳零能模是当前凝聚态物理领域的研究热点.马约拉纳零能模满足非阿贝尔统计,可以构建受拓扑保护的量子比特.这种由空间上分离的马约拉纳零能模构建的拓扑量子比特不易受局域噪声的干扰,具有长的退相干时间,在容错量子计算中具有重要的应用前景.半导体/超导体纳米线是研究马约拉纳零能模和拓扑量子计算的理想实验平台.本文综述了高质量半导体纳米线外延生长、半导体/超导体异质结制备以及相应的马约拉纳零能模研究方面的进展,并对半导体/超导体纳米线在量子计算中的应用前景进行了展望.  相似文献   

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