Digitized Processing Track Generation of a Computer Integrated Multi-Functional 5-Axis Laser Processing System

Based on the computer integrated and flexible laser processing system, an intelligent measuring sub-system was developed. A novel model has been built up to compensate the deviations of the main frame-structure, and a new 3-D laser tracker system is applied to adjust the accuracy of the system. To analyze the characteristic of all kind surfaces of automobile outer penal moulds and dies, classification of types of the surface、brim and ridge(or vale) area to be measured and processed has been established, resulting in one of the main processing functions of the laser processing system. According to different type of surfaces, a 2-D adaptive measuring method based on B?zier curve was developed; furthermore a 3-D adaptive measuring method based on Spline curve was also developed. According to the laser materials processing characteristics and data characteristics, necessary methods have been developed to generate processing tracks, they are explained in details. Measuring experiments and laser processing experiments were carried out to testify the above mentioned methods, which have been applied in the computer integrated and flexible laser processing system developed by the Institute of Mechanics, CAS.

Multiscale Method for Turbulent-Flow Computations

A main method of predicting turbulent flows is to solve LES equations, which was called traditional LES method. The traditional LES method solves the motions of large eddies of size larger than filtering scale An while modeling unresolved scales less than Delta_n. Hughes et al argued that many shortcomings of the traditional LES approaches were associated with their inabilities to successfully differentiate between large and small scales. One may guess that a priori scale-separation would be better, because it can predict scale-interaction well compared with posteriori scale-separation. To this end, a multi-scale method was suggested to perform scale-separation computation. The primary contents of the multiscale method are l) A space average is used to differentiate scale. 2) The basic equations include the large scale equations and fluctuation equations. 3) The large-scale equations and fluctuation equations are coupled through turbulent stress terms. We use the multiscale equations of n=2, i.e., the large and small scale (LSS) equations, to simulate 3-D evolutions of a channel flow and a planar mixing layer flow Some interesting results are given.

Numerical-Value Perturbation Method with Application of Solving Convective-Diffusion Integral Equation

The convective--diffusion equation is of primary importance in such fields as fluid dynamics and heat transfer hi the numerical methods solving the convective-diffusion equation, the finite volume method can use conveniently diversified grids (structured and unstructured grids) and is suitable for very complex geometry The disadvantage of FV methods compared to the finite difference method is that FV-methods of order higher than second are more difficult to develop in three-dimensional cases. The second-order central scheme (2cs) offers a good compromise among accuracy, simplicity and efficiency, however, it will produce oscillatory solutions when the grid Reynolds numbers are large and then very fine grids are required to obtain accurate solution. The simplest first-order upwind (IUW) scheme satisfies the convective boundedness criteria, however. Its numerical diffusion is large. The power-law scheme, QMCK and second-order upwind (2UW) schemes are also often used in some commercial codes. Their numerical accurate are roughly consistent with that of ZCS. Therefore, it is meaningful to offer higher-accurate three point FV scheme. In this paper, the numerical-value perturbational method suggested by Zhi Gao is used to develop an upwind and mixed FV scheme using any higher-order interpolation and second-order integration approximations, which is called perturbational finite volume (PFV) scheme. The PFV scheme uses the least nodes similar to the standard three-point schemes, namely, the number of the nodes needed equals to unity plus the face-number of the control volume. For instanc6, in the two-dimensional (2-D) case, only four nodes for the triangle grids and five nodes for the Cartesian grids are utilized, respectively. The PFV scheme is applied on a number of 1-D problems, 2~Dand 3-D flow model equations. Comparing with other standard three-point schemes, The PFV scheme has much smaller numerical diffusion than the first-order upwind (IUW) scheme, its numerical accuracy are also higher than the second-order central scheme (2CS), the power-law scheme (PLS), the QUICK scheme and the second-order upwind(ZUW) scheme.

The Intelligent Measuring Sub-System in the Computer Integrated and Flexible Laser Processing System

Based on the computer integrated and flexible laser processing system, develop the intelligent measuring sub-system. A novel model has been built to compensate the deviations of the main frame, a new-developed 3-D laser tracker system is applied to adjust the accuracy of the system. Analyzing the characteristic of all kinds of automobile dies, which is the main processing object of the laser processing system, classify the types of the surface and border needed to be measured and be processed. According to different types of surface and border, develop 2-D adaptive measuring method based on B?zier curve and 3-D adaptive measuring method based on spline curve. During the data processing, a new 3-D probe compensation method has been described in details. Some measuring experiments and laser processing experiments are carried out to testify the methods. All the methods have been applied in the computer integrated and flexible laser processing system invented by the Institute of Mechanics, CAS.

Two bifurcation processes for onset of oscillatory thermocapillary convection in a floating half zone

An overview on the onset of thermocapillary oscillatory convection in a floating half zone is provided, and it is a typical subject in the microgravity sciences related to the space materials science, especially the floating zone processing, and also to the microgravity fluid physics. The main interests are focused around the process for onset of oscillatory thermocapillary convection, which is known also as the bifurcation transition from quasi-steady convection to oscillatory convection. The onset of oscillation depends on a set of critical parameters, such as the Marangoni number, Prandtl number, geometrical parameters, and heat transfer parameters. Recent studies show that, there exists the bifurcation transition from steady and axial symmetric convection to the steady and axial non-symmetric convection before the onset of oscillation in cases of small Prandtl number fluids and in cases of larger Prandtl number fluids of fat liquid bridge with small aspect ratio. The transition process is a strong non-linear process because the velocity deviation has the same order of magnitude as that of an average flow after the onset of oscillation, and unsteady 3-D numerical simulation is suitable to do in depth analysis on strong non-linear process, and leads generally to a better comparison with the experimental results.

The Experimental and Numerical Studies on Gas Production from Hydrate Reservoir by Depressurization

A set of experimental system to study hydrate dissociation in porous media is built and some experiments on hydrate dissociation by depressurization are carried out. A mathematical model is developed to simulate the hydrate dissociation by depressurization in hydrate-bearing porous media. The model can be used to analyze the effects of the flow of multiphase fluids, the kinetic process and endothermic process of hydrate dissociation, ice-water phase equilibrium, the variation of permeability, convection and conduction on the hydrate dissociation, and gas and water productions. The numerical results agree well with the experimental results, which validate our mathematical model. For a 3-D hydrate reservoir of Class 3, the evolutions of pressure, temperature, and saturations are elucidated and the effects of some main parameters on gas and water rates are analyzed. Numerical results show that gas can be produced effectively from hydrate reservoir in the first stage of depressurization. Then, methods such as thermal stimulation or inhibitor injection should be considered due to the energy deficiency of formation energy. The numerical results for 3-D hydrate reservoir of Class 1 show that the overlying gas hydrate zone can apparently enhance gas rate and prolong life span of gas reservoir.

结构精修研究合成温度对LiFePO_4结构的影响

固相法合成具有橄榄石型结构的LiFePO_4晶体,合成温度分别为670、700、730℃.采用XRD结构精修对合成LiFePO_4的结构进行了研究.研究发现随着合成温度的变化,晶胞参数a、b和c发生变化,晶胞参数的变化是等比例的增加或减少.由于合成温度的变化,Fe-O八面体中Fe-O键长发生变化,Fe-O键长的变化将会使得Fe的3 d轨道能量发生变化.相对于合成温度670、730℃,在700℃合成的LiFePO_4晶体具有最大的锂离子扩散有效面积.

MDT三维工具集在齿轮造型与分析中的应用

通过MDT三维工具集方便地实现了直齿轮的造型，重点说明了用基于特征造型的方法在MDT环境下实现斜齿轮造型的详细过程，并用MDT的有限元分析功能对齿轮的受力善进行了分析。整个过程在MDT的集成环境下完成，对齿轮的工程设计具有较高的实用价值。

Transparent colloid containing upconverting nanocrystals: An alternative medium for three-dimensional volumetric display

We report an alternative medium of transparent upconverting colloid containing lanthanide ion doped NaYF4 nanocrystals for three-dimensional (3D) volumetric display. The colloids exhibit tunable upconversion luminescence with a wide spectrum of colors by adjusting the doping concentrations of the nanocrystals and the compositions of the colloids. Our preliminary experimental result indicates that an upconverting colloid-based 3D volumetric display using a convergent, near infrared laser beam to induce a localized luminescent spot near the focus is technically feasible. Therefore arbitrary 3D objects can be created inside the upconverting colloid by use of computer controlled 3D scanning systems. (C) 2008 Optical Society of America

横断山区的翠雀属植物:分类学和细胞学

翠雀属Delphinium L.是毛茛科中的一个大属，全世界有300－400 余种，广布于北半球温带地区。我国是世界上记载翠雀属植物种类最多的国家，尤以西南横断山区种类最为丰富。 通过文献查阅、标本室研究和野外考察，本文对我国特别是横断山区翠雀属植物的主要形态性状在居群间和居群内的变异式样进行了初步分析，认为根的形态、叶的分裂程度、植株尤其是花序轴和花梗被毛与否以及毛被类型、小苞片的形状和位置、退化雄蕊的颜色、上萼片的形状、心皮数目和种子形态特征是比较可靠的分类性状。但性状之间的相关性往往较小，即使是通常比较稳定的分类性状有时也表现出不同程度的变异，因此同一性状对于不同等级分类群的划分和在不同分类群中的分类价值常不一样。在具体的分类处理中，应具体情况具体分析，尽可能利用较多的分类学性状或性状组合。 根据上述对我国翠雀属植物主要形态性状变异式样的理解，本文主要对我国西南横断山区及其邻近一些地区的翠雀属植物进行了力所能及的分类修订：将42 种和22 变种降为异名，提出2 新组合(毛梗黑水翠雀D. potaninii var. mollipes　(W. T. Wang) Q. Yuan & Q. E. Yang 和腺毛康定翠雀D. tatsienense var. pseudomosoynense (W. T. Wang) Q. E. Yang & Q. Yuan)，澄清了直距翠雀D. tenii Lévl. 的名实问题和Munz 等学者对我国翠雀属植物标本的鉴定错误以及由此引起的我国有关翠雀属植物的地理分布的混乱; 另有两种( 硕片翠雀D. grandilimbum W. T. Wang & M. J. Warnock 和永宁翠雀D. yongningense W. T. Wang & M. J. Warnock)因未见到模式标本，故暂存疑。本文讨论到的我国翠雀属植物共有87 种、10 变种。 为了在染色体水平上了解横断山区翠雀属植物的物种形成和分化，同时增加对整个翠雀族tribe Delphineae Warming 植物染色体进化的理解，本文报道了我国主要采自该地区的乌头属Aconitum L. 30 种、1 变种共40 个居群和翠雀属 48 种、3 变种共87 个居群的染色体数目，分析了30 种、1 变种乌头属植物和 46 种、3 变种翠雀属植物的核型，发现46 种、3 变种翠雀属植物为二倍体(2n = 2x=16)，1 种(黄毛翠雀D. chrysotrichum Finet & Gagnep.)为四倍体(2n = 4x =32)，1种(螺距翠雀D. spirocentrum Hand.-Mazz.)有二倍体和四倍体两种细胞型，3 种(宽距翠雀D. beesianum W. W. Smith、裂瓣翠雀D. mosoynense Franch.和康定翠雀 D. tatsienense Franch.)的个别居群有B 染色体出现。这表明横断山区翠雀属植物的物种形成主要在二倍体水平上进行。可能由于核型直向选择（karyotypic orthoselection）的结果，我国翠雀属植物的核型就整体情况而言在属内相当一致，属内核型分化不如乌头属中明显，外部形态上显得最为原始的种类如短距翠雀 D. forrestii Diels 和毛翠雀D. trichophorum Franch.的核型与其他多年生种类的核型相比并无明显区别。尽管如此，翠雀属植物的核型在属内仍表现出一定程度的分化：在多年生种类中，大理翠雀群(D. taliense group)的种类的染色体内部不对称性(intrachromosomal asymmetry) 程度较高, 但染色体之间的不对称性 (interchromosomal asymmetry)程度偏低;一年生种类与多年生种类相比，我国唯一的一年生种还亮草D. anthriscifolium Hance 染色体之间不对称性最高，该种染色体内部不对称性程度在翠雀族中也偏高，因此就其核型的整体不对称性程度而言，在翠雀属乃至整个翠雀族中最高，而地中海分布的一年生种类的染色体内部不对称性明显增强, 但染色体之间的不对称性在翠雀族中最低。这种核型分化的系统学和生物地理学意义尚不清楚，以后需进一步研究。与乌头属相比，翠雀属植物的染色体通常较小，核型中st 染色体明显增多（可达6 对），核型的整体不对称性程度逐渐增强; 虽然乌头属牛扁亚属Aconitum subgen. Lycoctonum (DC.) Peterm.的二倍体种类也一般具有较多的st 染色体（4 对），但这些st 染色体比乌头亚属Aconitum L. subgen. Aconitum和露蕊乌头亚属Aconitum subgen. Gymnaconitum (Stapf) Rapaics 植物核型中相对应的m 或 sm 染色体以及翠雀属和飞燕草属Consolida (DC.) S. F. Gray 植物中相对应的st 或偶尔出现的sm 染色体要大。特别应当注意的是牛扁亚属中外部形态上显得最为原始的展喙乌头A. novoluridum Munz 的核型具有较多而且较大的sm 染色体，所以我们认为展喙乌头的核型保留了较多的原始性质，那些核型中具有较多st 染色体的牛扁亚属植物应当是该亚属中在核型上已比较特化的种类。这一结果不支持前人提出的乌头属植物的核型有从st 染色体进化到m 或sm 染色体的趋势的观点。就整个翠雀族而言，从现有资料看，其核型的进化趋势应当为：(1) 染色体从大进化到小, 从m 或sm 染色体进化到st 染色体;(2) 核型的整体不对称性程度逐渐增强，即核型的二型性从多年生的牛扁亚属植物到翠雀属植物的一年生的还亮草亚属Delphinium subgen. Delphinium 而愈趋明显。翠雀族植物核型的进化方向与整个毛茛科核型的进化方向看来是一致的，即都向核型不对称性增强的方向进化。

不同氮肥管理措施对草坪生长和无机氮淋洗的影响

本研究采用室外盆栽试验，模拟运动场坪床结构，研究不同氮肥种类、不同施氮频率、施氮和降雨时间间隔对草地早熟禾草坪质量、草坪生长和无机氮淋洗的影响，并探讨在北京地区气候条件下，草坪在不同氮肥管理措施下的氮素去向及环境风险。主要结论如下： 1. 氮肥种类对草坪质量和草坪生长有显著影响。试验前期（春季），草坪颜色和密度质量、草坪草生长速度和草屑全氮含量的排序为尿素 > CU3M（自研包膜尿素）> IBDU（进口缓释肥），而试验后期（秋季）则为CU3M = IBDU > 尿素。草坪合格颜色质量持续时间和成坪速度的排序为尿素 > CU3M > IBDU。在新建草坪选择缓释肥进行早春施肥时，应混施一定比例的速效肥。 2. 施氮频率对草坪外观质量评分、草坪生长速度、草屑总生物量、草屑全氮含量和根系分布状况有显著影响。U6处理的草坪合格颜色质量持续时间最长，增加施氮频率没有降低新建草坪生长速度和草屑全氮含量的波动幅度。 3. 夏季（6~8月）渗漏液体积占全年的比例最高，为75.0%~82.4%。新建草坪初期的淋洗风险较大，渗漏液硝态氮浓度在第1次超过10 mg N•L-1，尿素分6次施用可降低这次的渗漏液硝态氮浓度。在合理施氮量内，草坪成熟后的无机氮淋洗量很小，且草坪对雨水中的无机氮有吸收和过滤作用。 4. 春季施用氮肥的吸收利用率为48.0%~72.6%，草屑吸收量最高，占38.5%~48.7%，地上部吸收量占19.6%~22.1%，根系吸收量在7.3%以下。施肥处理的无机氮淋洗损失量仅为0.23~0.42 g N•m-2，与CK无显著差异，草地早熟禾12 g N•m-2的年施氮量对环境的风险很小。 5. 初秋施氮5 g N•m-2，可以保持草地早熟禾秋季的良好颜色和密度质量，草坪草氮素吸收利用率高达87.4%~99.7%，其中草屑带走量占24.3%~34.2%，地上部吸收量占43.3%~59.6%，根系吸收量占14.2%~19.1%。 6. 施氮和模拟降雨的时间间隔对渗漏液硝态氮浓度有显著影响，间隔6 d和9 d模拟降雨后的渗漏液硝态氮浓度最高，显著高于间隔3 d和12 d模拟降雨的结果。初秋合理施氮的渗漏液硝态氮浓度在1.0 mg N•L-1 以下，环境风险较小。

Molecular dynamics research of G249 and S249 substitutions of p53 protein.

,The molecular dynamics research of the core domain of p53 protein crystal structure shows that besides the stability in biochemistry this domain also shows a high stability in molecular mechanics. Based on that work, the residue R249 was substituted with amino acids Gly and Ser respectively, and molecular dynamics researches were performed separately. The results show that these substitutions cause a relax tendency between loop2 and 3 domains, leading to an alteration of the whole conformation of p53 core domain and ruining its stability. The results visually explains the mechanism of p53 changes in immunological and biochemical reactions, which are caused by 249 residue substitutions from 3-D structure variations.

点柄乳牛肝菌子实体中抗HIV-1活性成分

目的 研究点柄乳牛肝菌的化学成分,并对分离鉴定的化合物进行抗HIV-1的活性研究.方法 将野外采集的点柄乳牛肝菌子实体用溶剂提取,采用硅胶柱色谱进行分离,通过波谱技术(NMR,MS,IR等)对结构进行鉴定.结果 分离鉴定了9个化合物,分别为:酒渣碱(Ⅰ)、5a,8a-过氧麦角甾-6,22-二烯-3β-醇(Ⅱ)、麦角甾-5,7,22-三烯-3β-醇(Ⅲ)、麦角甾-5,7,22-三烯-3β-O-β-D-吡喃葡萄糖苷(Ⅳ)、尿嘧啶(Ⅴ))、硫代乙酸酐(Ⅵ)、硬脂酸(Ⅶ)、3-吡啶甲酸(Ⅷ)和D-阿洛糖醇(Ⅸ).结论 化合物Ⅰ为首次从高等真菌中分离.经生物活性测试,该化合物具有抗HIV-1活性,对C8166细胞的毒性较小,CC50为87.86 μg/mL,对HIV-1诱导C8166细胞形成合胞体抑制的EC50为7.27 μg/mL,治疗指数(TI值)为12.09.

眼镜蛇毒因子消耗补体对大鼠移植心急性排斥反应的抑制作用

目的 研究中华眼镜蛇毒因子(CVF)消耗补体对大鼠心脏移植急性排斥反应的影响.方法 以近交系BN大鼠为供者,Lewis大鼠为受者,建立腹腔异位心脏移植模型.实验分为2组,每组8只.CVF组:心脏移植术前3 d、2 d时,经受者尾静脉注射CVF 50 μg/kg;术前12 h至移植心停跳时,经尾静脉注射CVF 20 μg/kg,每2 d注射1次.对照组:术前、术后不给予受者任何特殊处理.术后观察移植心的存活时间,测定术后第1、3、5和6d及移植心停跳时的血清总补体活性(CH50法)、移植心C3沉积及CD3+T细胞浸润情况,并观察移植心的病理变化.结果 CVF组和对照组的移植心存活时间分别为(11.69±0.72)d和(6.65±0.35)d,两组比较,差异有统计学意义(P＜0.01).CVF组移植心组织内C3沉积和CD3+T细胞浸润程度均较对照组同期明显减轻,病理损害程度也较对照组同期明显减轻.结论 CVF消耗补体对大鼠心脏移植急性排斥反应起到了明显的抑制作用,从而延长移植心存活时间.

甘草粗提物对鲫的抗应激及免疫保护功效研究

采用腹腔注射和混饲投喂两种方式研究中药甘草(Glycyrrhiza uralensis Fiseh)粗提物对鲫(Carassius auratus)的抗应激和免疫保护功效。将一部分粗提物按0.5%和2%的质量分数制成药饵投喂实验鲫,分别在第14 d、28 d、35 d、42 d、56 d采集血样;将另一部分粗提物用无菌生理盐水按0.5%和2%的浓度配成针剂腹腔注射鲫,分别在第3 d、7 d、14 d、21 d、28 d采集血样。结果显示:投喂实验中药物组和对照组血清皮质醇水平均呈先升后降趋势,除第14 d