参量调制驱动环形等离子体稳态电流的简化分析

本文用简化模型分析托卡马克装置,建议用等离子体往径向速度振荡和角向磁场振荡的相互作用产生一个定常环向电动势以驱动稳态电流。这可由按一定相位差调制两个外加参量来达到。按反应堆参数估计,这种调制频率可以是工业频率。

高功率CO_2激光积分球涂层的研制

对用等离子喷涂工艺制取的积分球涂层进行了研究。应用-100+140目铝粉在铝基片上喷涂的涂层对10.6微米的红外光有较理想的漫反射性能。试验结果表明,与烧结法制取的漫反射涂层比较,其性能相同,而工艺简单。

连续介质力学与断裂

<正> 在这篇文章里,我们结合断裂问题回顾连续介质办学的发展,并指出,为了更深地理解和描述断裂现象,还需要进一步完善连续介质力学。 一、经典弹塑性理论应用于断裂时的局限性和Grifith的理论 现讨论一维应变条件下裂纹的扩展问题。我们假设 1.材料是均匀的,就是说,所讨论的材料是没有内部结构的; 2.材料是弹性的,但允许有非线性和大变形所导致的几何非线性;

测量万瓦级CO_2激光器连续输出功率的鼠笼式能量计

<正>CO_2激光器连续输出功率可达数万瓦以上,运转时间短的仅几秒,一般的功率计很难兼顾承受高功率密度和响应时间快这两个要求.因此我们采用配有旋转盘衰减器的鼠笼式能量计进行测量.Baker给出,鼠笼能量计在不小于毫秒时间里最大可接收的能量密度为10焦耳/厘米~2.我们制作的74-6~#鼠笼能量计的实验表明,只要通过旋转盘衰减器的每个光脉冲满足上述要求,在重复频率为数十次/秒的连续光脉冲照射下,仍可实现测量.74-6~#已实测了3×10~4瓦CO_2激光器连续输出功率,它的最大功率密度已超过6×10~3

Heating, current drive and confinement regimes with the JET ICRH and lhcd systems

During its 1990 operation, 2 large RF systems were available on JET. The Ion Cyclotron Resonance Heating (ICRH) system was equipped with new beryllium screens and with feedback matching systems. Specific impurities generated by ICRH were reduced to negligible levels even in the most stringent H-mode conditions. A maximum power of 22 MW was coupled to L-mode plasmas. High quality H-modes (tau-E greater-than-or-equal-to 2.5 tau-EG) were achieved using dipole phasing. A new high confinement mode was discovered. It combines the properties of the H-mode regime to the low central diffusivities obtained by pellet injection. A value of n(d) tau-E T(i) = 7.8 x 10(20) m-3 s keV was obtained in this mode with T(e) approximately T(i) approximately 11 keV. In the L-mode regime, a regime, a record (140 kW) D-He-3 fusion power was generated with 10 - 14 MW of ICRH at the He-3 cyclotron frequency. Experiments were performed with the prototype launcher of the Lower Hybrid Current Drive (LHCD) systems with coupled power up to 1.6 MW with current drive efficiencies up to < n(e) > R I(CD)/P = 0.4 x 10(20) m-2 A/W. Fast electrons are driven by LHCD to tail temperatures of 100 keV with a hollow radial profile. Paradoxically, LHCD induces central heating particularly in combination with ICRH. Finally we present the first observations of the synergistic acceleration of fast electrons by Transit Time Magnetic Pumping (TTMP) (from ICRH) and Electron Landau Damping (ELD) (from LHCD). The synergism generates TTMP current drive even without phasing the ICRH antennae.

超声速燃烧室凹腔火焰稳定器的数值模拟

为分析凹腔火焰稳定器在超声速燃烧室中的流动特性,运用数值模拟方法研究了凹腔对H2超声速燃烧的作用规律。通过对比分析不同凹腔长深比L/Du,后缘倾角θ,后缘深度D_d和H_2喷射位置Ljet对燃烧室性能的影响,发现凹腔的火焰稳定机制主要在于富含自由基的高温回流区;L/D_u=7-9,θ=30°,D_u/D_d=1.0和L_(jet)=24mm的燃烧室强化混合燃烧的性能较好,可以获得较高的燃烧效率和总压恢复。

Annual report 2002 - North Pacific Marine Science Organization (PICES). Eleventh meeting, Qingdao, People's Republic of China, October 18-16, 2002

Report of Opening Session (pdf 51 KB) Report of Governing Council Meeting(pdf 136 KB) Report of the Finance and Administration Committee (pdf 48 KB) Reports of Science Board and Committees: Science Board (pdf 71 KB) Biological Oceanography Committee (pdf 66 KB) Working Group 14: Effective sampling of micronekton Marine Birds and Mammals Advisory Panel Fishery Science Committee (pdf 36 KB) Working Group 16: Climate change, shifts to fish production, and fisheries management Marine Environmental Quality Committee (pdf 39 KB) Working Group 15: Ecology of Harmful Algal Blooms (HABs) in the North Pacific Physical Oceanography and Climate Committee (pdf 49 KB) North Pacific Data Buoy Advisory Panel Working Group 17: Biogeochemical data integration and synthesis Technical Committee on Data Exchange (pdf 29 KB) Implementation Panel on the CCCC Program (pdf 43 KB) BASS Task Team (pdf 30 KB) Iron Fertilization Experiment Advisory Panel MODEL Task Team (pdf 28 KB) MONITOR Task Team (pdf 34 KB) Summary of Continuous Plankton Recorder activities in 2002 REX Task Team (pdf 21 KB) Documenting Scientific Sessions (pdf 140 KB) List of Participants (pdf 59 KB) List of Acronyms (pdf 21 KB)

热喷涂构件中残余应力的理论分析

本文发展一种新的分析涂层结构（平板、梁）热残余应力的模型，可以研究骤冷过程（Quenching）和冷却过程（Cooling）在涂层结构内引发的残余应力分布。与以往模型相比，其优势在于：它可以考虑源于喷涂过程的涂层孔隙率、温度梯度等因素对于涂层和基底内残余应力的影响。其中孔隙率和温度分布由计算机模拟涂层沉积过程得到。另外，当基底的材料和几何参数被固定时，我们分析了诸如涂层的理想模量、厚度、热膨胀系数等参数，对于涂层结构中最终残余应力分布的改变机理。

The hydrography of Elkhorn Slough: a shallow California coastal Eebayment: Annual Report, Part 2, 1973

From October 1970 through February 1972, temperature, salinity, dissolved oxygen, secchi depth and five major nutrients were observed at approximately monthly intervals in Elkhorn Slough and Moss Landing Harbor. In addition, similar hourly observations were made during two tidal studies during the wet and dry seasons. From the salinity measurements during the summer, a salt balance for Elkhorn Slough is formulated and rnean eddy diffusion coefficients are determined. The diffusion nlodel applied to longitudinal phosphate distributions yielded a mean diffusive flux of 12 kg P04/day (140 pg-at/m^2/day) for the area above the mean tidal prism. Consistent differences, apparently due to differing regenerati on ra tes, were observed in the phosphate and nitrogen distributions. Bottom sediments are proposed as a possible source for phosphate and as a sink for fixed nitrogen. Dairy farms located along central Elkhorn Slough are apparently a source for reduced nitrogen. During summer, nitrogen was found to be the limiting nutrient for primary production in the upper slough. Tidal observations indicated fresh water of high nutrient concentration consistently entered the harbor from fresh water sources to the south. This source water had a probable phosphate concentration of 40 to 60 ug-at/l and seasonally varying P:N ratio of 1:16 and 1:5 during the winter and summer respectively. Net production and respiration rates are calculated from diurnal variations in dissolved oxygen levels observed in upper Elkhorn Slough. Changes in phosphate associated with the variations in oxygen was close to the accepted ratio of 1:276 by atoms. Document is 88 pages.

俄罗斯《气动力学和气体动力学》新刊出版发行

<正> 与其它许多流体力学的学术刊物覆盖了范围宽广各类问题的作法不同,新出版的刊物《气动力学和气体动力学》集中发表有关超声速和高超声速等高速气流问题的科学论文.由于此类问题必须运用高效计算方法,该刊发表研究复杂流动以及伴随的高温物理化学过程(例如化学反应,分子内态自由度激波,电离,辐射等等)所发展的各种先进数值模拟方

俄罗斯《力学进展》

<正> 从2002年开始,莫斯科大学的力学研究所与力学数学系以及俄罗斯科学院理论和应用力学学会(NCTAM)赞助的力学编辑中心共同主办出版了一个新的俄文学术季刊《力学进展》.该刊论文包括邀请和投稿两类,内容将覆盖力学学科的所有分支,主要是评述力学领域研究进展和重要成果,涉及到系统论,流体力学,固体力学以及力学在工程技术与自然科学中的应用等等.该刊计划发表一系列重要的档案文献,以期反映力学发展史的关键事件,介绍创建和推动力学不同分支发展的重要学者和研究群体,关注力学界杰出人物生涯的闪光点.该刊还将提供由IUTAM,Earomech,CISM俄罗斯NCTAM等机构组织的重要活动和重新组合情况,以

热对流现代问题国际会议

<正> 热对流现代问题国际会议于2003年11月24～27日在俄罗斯别尔姆州立大学召开,会议由俄罗斯理论和应用力学国家委员会,俄罗斯科学院国家传热/传质委员会,别尔姆州立大学,俄罗斯科学院乌拉尔分院连续介质力学所,俄罗斯力学问题研究所等单位共同举办.中国、德国、意大利、法国、澳大利亚等国派代表参加了会议,俄罗斯代表约有百人,包括一批大学教授.

气脉冲发生器中火焰传播与压力变化的研究

燃烧气脉冲发生器用于电厂锅炉除灰，其工作原理是预混可燃气体在右端部分开口在内部有障碍物的容器中快速燃烧，以形成一定的压力脉冲，并产生作用于积灰表面的射流和冲击波，火焰在端流扰动装置的作用下不断加速，容器中的压力不断上升，火焰传播愈快，压力波形愈陡，压力锋值愈高，针对这些现象，该文进行了实验和理论研究。主要研究了乙炔，水煤气，液化石油气和甲烷4种燃料，在不同燃料浓度，不同阻塞比时对火焰传播和压力上升的影响，计算和实验结果对实验应用有指导作用。