多层金刚石薄膜制备工艺和应力分析研究

采用热丝化学气相沉积方法，优化金刚石薄膜制备工艺。通过改变甲烷浓度成功制备出厚度均匀的多层金刚石薄膜，实现了多种调制周期的金刚石薄膜制备，调制周期最小至100 nm。通过拉曼光谱和X射线衍射方法对单层以及多层金刚石薄膜进行应力分析，发现单层结构中，微米金刚石薄膜应力最大，随着金刚石晶粒尺寸的减小，薄膜应力减小；多层金刚石薄膜结构中，微米层与纳米层均匀交替生长，有效地降低了薄膜应力，有利于提高金刚石薄膜在应用中的稳定性。     

丽江文化“走出去”的思考

丽江文化在19世纪中后期至20世纪初期就引起了海外学者与传教士的关注,20世纪晚期,伴随着旅游经济的发展,丽江成为一个重要的海外游客旅游目的地与文化输出窗口.其生产要素、需求状况、文化相关产业和支持产业表现及面向国际发展的战略与定位成为文化“走出去”的竞争优势,而服务水准与产业联动则是两个亟待加强的弱项.     

Synthesis of novel superhard materials under ultrahigh pressure

Superhard materials are solids whose Vickers hardness is beyond 40 GPa. They have wide applications in industry such as cutting and polishing tools, wear-resistant coatings. Most preparations of superhard materials are conducted under extreme pressure and temperature conditions, not only for scientific investigations, but also for the practical applications. In this paper, we would introduce the recent progress on the design and preparations of novel superhard materials, mainly on nanopolycrystalline diamond, B–C–N superhard solid solutions, and cubic-Si3N4/diamond nanocomposites prepared under ultrahigh pressure and high temperature（HPHT）, using multi-anvil apparatus based on the hinged-type cubic press. Bulk materials of all these superhard phases have been successfully synthesized and are systematically tested. We emphasize that ultra-HPHT method plays an important role in the scientific research and industrial production of superhard materials. It provides the driving forces for the light elements forming novel superhard phases as well as the way for sintering high-density nanosuperhard materials.     

超音流中菱形口射流及相互作用激波结构

基于在不同射流角(10°,27.5°,45°,90°)和动量比下(0.1 MPa,0.46 MPa)对音速次膨胀射流通过菱形口喷射到马赫5横穿主流的实验及圆形射流器的对比实验,研究了次膨胀射流与超音横穿主流相互作用流场.结果表明在低射流角和动压比下相互作用激波保持附着,脱体激波产生lambda激波,lambda激波出现于高射流角、动压比下和圆形喷射器情况.射流外边界高度在射流进入主流过程中不断增加,而且在大射流角下较大.由于侧向扩展,羽流变窄,但圆形喷射器无此变化,接近喷射口的紊流卷吸结构大小随入射角增大,穿透量随喷射角和动压比的增加而增大,在近场圆形喷射器的穿透量超过菱形喷射器,但菱形喷射器的下游穿透量会超过圆形喷射器.     

Effect of additive boron on type-Ib gem diamond single crystals synthesized under HPHT

The boron-doped type-Ib gem diamond crystals were synthesized successfully by adding amorphous boron into a system of graphite and Kovar catalyst under high pressure and high temperature (HPHT).The effect of additive boron on type-Ib gem diamond was extensively studied including the growth characteristic,morphology and nitrogen concentration.The synthesized boron-doped type-Ib gem diamond crystals were characterized by optical microscope (OM),scanning electron microscope (SEM) and infrared spectrometer (IR)...     

Effects of carbon diffusing field in alloy solvent on the growth of tower-shape diamond single crystal

High-quality type-Ib tower-shape diamond single crystals were synthesized in cubic anvil high pressure apparatus (SPD-6×1200) at 5.4 GPa and 1250-1450°C. The (100) face of seed crystal was used as the growth face, and FeNiMnCo alloy was used as the solvent/catalyst. Two kinds of carbon diffusing fields (type-B and type-G) were simulated by finite element method (FEM). Using the two kinds of carbon diffusing fields, many diamond single crystals were synthesized. The effects of carbon diffusing fields on the ...     

基于改进期望最大化算法的分布式视频编码

目前,分布式视频编码(DVC)由于具有低复杂编码特性而成为视频编码领域的研究热点。DVC中,边信息性能对系统性能影响很大,一般而言,边信息性能越好,则整个系统压缩性能越好。本文研究了一种基于贝叶斯准则的期望最大化(Expectation Maximization,EM)边信息产生方法,并从运动搜索模板和初始概率模型两方面对EM算法提出了改进。实验表明,在几乎相同的率失真性能下,两种改进算法的学习时间分别缩短了30%和16%。     

微波功率对光学级金刚石膜生长的影响

采用微波PCVD系统进行了高品质透明金刚石膜的制备,在金刚石膜的沉积过程中,微波功率的变化直接影响着金刚石膜的生长和质量。用Raman,SEM等手段对金刚石膜的生长特性进行了表征。     

从波特钻石理论看河池市旅游业发展的有利条件

波特钻石理论适用于旅游业竞争力的研究，运用这一理论分析河池市旅游业发展，可见在生产要素、需求状况、相关和支持产业以及企业的战略、组织结构和竞争程度等四个基本要素和政府、机遇两个辅助因素方面都具有一定的有利条件，应加以充分利用。     

福建电子信息产业提升全球竞争力分析与对策——基于波特的“钻石理论模型”

运用波特的“钻石理论模型”对福建电子信息产业现状进行分析，发现其在企业战略、结构与竞争状态等方面还非常薄弱，亟需进行产业链和供应链的整合，以提高全球竞争力。提出福建电子信息产业可利用海西加快建设的良好契机，通过“走出去”和“请进来”的方式，吸纳台湾电子信息产业的创新技术和管理经验，以推动电子信息产业链和供应链的整合，实现产业战略转型升级的建议。