一种基于旋转体的摄像机定位方法

基于旋转体的摄像机定位是单目合作目标定位领域中的涉及较少并且较为困难的一个问题,传统的基于点基元、直线基元及曲线基元的定位方法在用于旋转体定位过程中都存在相应的问题.文中设计了一种由4个相切椭圆构成的几何模型,该模型环绕于圆柱体表面,利用二次曲线的投影仍然是二次曲线的特性和椭圆的相应性质能够得到唯一确定模型位置的3个坐标点,从而将旋转体定位问题转化为P3P问题.在对P3P的解模式区域进行分析后,推导了根据模型上可视曲线的弯曲情况来确定P3P问题解模式的判别方法,并给出证明过程.仿真实验表明了这种模型定位方法的有效性.最后利用这个模型引导机械手完成目标定位的实验.

贵州4个洞穴滴水对大气降雨响应的动力学及其意义

在雨季, 采用NaCl 示踪的方法, 对贵州珠江水系的4 个岩溶洞穴(荔波凉风洞、都匀七星洞、安顺将军洞和镇宁犀牛洞)滴水点水的来源、滴水对大气降雨的响应尺度、水动力学过程等进行研究, 揭示出由于岩溶洞穴环境、水运移路径的联通性、水动力学过程等的不一致, 4 个洞穴的不同滴水点滴水对大气降雨响应的时间尺度为0~40 天. 根据水在洞穴顶板的运移特性、水的运行方式、水头类型等水文学特性的差异, 将这4 个洞穴的滴水点划分成5 种水动力学类型. 由于不同洞穴不同滴水点水-土、水-岩作用的时间尺度、作用方式、水运移路径等的差异, 影响到岩溶次生沉积物的物质来源及量度标准,加之不同洞穴各滴水点水动力条件的极大差异, 岩溶次生沉积物过去环境变化指标的解译应该有洞穴滴水水动力条件的结果作为支撑. 根据目前对这4 个洞穴众多滴水点滴水电导率的监测, 电导率与大气降雨量的一致变化, 意味着洞穴滴水形成的岩溶次生沉积物的元素含量具有记录岩溶环境过去变化的意义, 但应以多个点的研究结果来保证解译的正确性.

Ofensywa Wielkanocna 1972 (kulminacyjny punkt wojny wietnamskiej)

Wydział Historyczny: Instytut Historii

Polo de Desarrollo de Artesanías de Colombia : Proyecto No. 4 : Taller Comunitario – Pereira (Risaralda).

21 hojas : plano.

Ilustración de algunos procesos de producción cerámica de Coco Viejo en Inírida - Guinía, en 2005.

13 hojas : ilustraciones, fotografías a color

X-ray crystallographic structures of two lamotrigine analogues: (I) 3,5-diamino-6-(2-chlorophenyl)-1,2,4-triazine water solvate and (II) 3,5-diamino-6-(3,6-dichlorophenyl)-1,2,4-triazine methanol solvate

The X-ray crystal structures of two lamotrigine derivatives (I) 3,5-diamino-6-(2-chlorophenyl)-1,2,4-triazine, C9H8ClN5, (465BL) as a hydrate, and (II) 3,5-diamino-6-(3,6-dichlorophenyl)-1,2,4-triazine, C9H7Cl2N5, (469BR) as a methanol solvate, have been carried out at liquid nitrogen temperature and room temperature, respectively. A detailed comparison of the two structures is given. Both are centrosymmetric with (I) in the orthorhombic space group Pbca, a = 12.2507(3), b = 15.7160(6), c = 21.71496(9) angstrom, Z = 16, and (II) in the monoclinic space group C2/c, a = 38.553(3), b = 4.9586(2), c = 14.546(2) angstrom, beta = 111.59(1)degrees, Z = 8. Final R indices [I > 2sigma(I)] for (I) are R1 = 0.0670, wR2 = 0.1515 and for (II) R1 = 0.0434, wR2 = 0.1185. Structure (I) has water of crystallization in the lattice and (II) includes a solvated CH3OH. Structure (I) is characterized by having two crystallographically independent molecules, A and B, of 465BL, per asymmetric unit. Molecule B has a very unusual feature in that the 2-chlorophenyl ring is statistically disordered, occupying site (1) in 87.5% of the structure and site (2) in 12.5% of the structure. Sites (1) and (2) are related by an exact 180 degrees pivot of the phenyl ring about the ring linkage bond. The presence of two independent molecules per asymmetric unit provides an ideal opportunity for the conformational flexibility of the molecule 465BL to be studied. Structure (I) also includes a further unusual feature in that the lattice contains one fully occupied water molecule and an additional solvated water which is only 33% occupied.

Polyunsaturated fatty acids in the pathogenesis and treatment of multiple sclerosis

Epidemiological, biochemical, animal model and clinical trial data described in this overview strongly suggest that polyunsaturated fatty acids, particularly n-6 fatty acids, have a role in the pathogenesis and treatment of multiple sclerosis (MS). Data presented provides further evidence for a disturbance in n-6 fatty acid metabolism in MS. Disturbance of n-6 fatty acid metabolism and dysregulation of cytokines are shown to be linked and a "proof of concept clinical trial" further supports such a hypothesis. In a randomised double-blind, placebo controlled trial of a high dose and low dose selected GLA (18:3n-6)-rich oil and placebo control, the high dose had a marked clinical effect in relapsing-remitting MS, significantly decreasing the relapse rate and the progression of disease. Laboratory findings paralleled clinical changes in the placebo group in that production of mononuclear cell pro-inflammatory cytokines (TNF-alpha, IL-1 beta) was increased and anti-inflammatory TGF-beta markedly decreased with loss of membrane n-6 fatty acids linoleic (18:2n-6) and arachidonic acids (20:4n-6). In contrast there were no such changes in the high dose group. The improvement in disability (Expanded Disability Status Scale) in the high dose suggests there maybe a beneficial effect on neuronal lipids and neural function in MS. Thus disturbed n-6 fatty acid metabolism in MS gives rise to loss of membrane long chain n-6 fatty acids and loss of the anti-inflammatory regulatory cytokine TGF-beta, particularly during the relapse phase, as well as loss of these important neural fatty acids for CNS structure and function and consequent long term neurological deficit in MS.

Una prueba de la técnica multi-espécimen para determinar paleointensidad utilizando material arqueomagnetico: resultados preliminares con arcillas quemadas Tunecinas

The multispecimen palaeointensity technique of Dekkers & Böhnel (2006) has been tested on archaeomagnetic material from five kilns from Tunisia. In a previous study all five kilns yielded good quality archaeointensities based on Thellier-type double heating experiments. Results obtained using the multispecimen technique compared well with the previously studied Thellier-type results, with a slight tendency towards lower values. Markedly lower values were observed in two kilns, results that were improved by increasing the proportion of the natural remanence remagnetised in the partial thermoremanence acquisition. One of the kilns showed a multicomponent remanence (due to partial heating) and gave relatively poor results.

The Role of Tool/Sheet Contact in Plug-Assisted Thermoforming.

Plug-assisted thermoforming produces a wide range of polymer products through a combination of deformation by air pressure and contact with tool surfaces. In this paper the role of tool/sheet contact in determining the process output is investigated. A combination of thermoforming, friction and heat transfer tests were carried out on common tool and sheet materials. The results show that the typical friction coefficients for the material combinations are within the range 0.1 to 0.3, but the values rise sharply on approaching thermoforming temperatures. Thermal imaging tests demonstrate that all of the plug materials significantly cool the heated sheet on contact, even over very short periods of time. The temperature of the plug is very important. At low plug temperatures heat transfer effects predominate, whereas at high plug temperatures friction effects predominate. A plug temperature of approximately 100oC balances these effects and creates the most effective material distribution.