基于逆向参数化的B样条曲面重建算法

目的解决B样条曲面重建问题中矩形拓扑网自动生成和参数化两大难点问题,提出一种基于逆向参数化的B样条曲面重建算法.方法首先构建基曲面,在基曲面上根据参数(u,v)进行采样,沿其法线方向进行数据的滤波和精简,求得参数(u,v)对应的精简点,然后对采样求取的精简点集进行B样条曲面拟合,该方法提供了B样条曲面重建的一个新思路.结果新算法突破了传统密集散乱点云数据的B样条曲面重建基本过程,采用与正向参数化相反的过程进行参数化,解决了B样条曲面重建问题中矩形拓扑网自动生成和参数化的难题;具体试验分析表明新算法不仅在参数化的同时完成了数据滤波和精简,而且在时间和迭代效率方面都具有优势.结论新算法避免了求取法线的迭代过程,并且可以较容易的实现矩形拓扑网的自动生成,新算法在自主开发的智能测量建模加工一体化装备中得到了应用验证.

RH6-B机器人的通信协议

RH6-B机器人控制器是基于CAN总线的控制器,具有CAN总线的接口。实现了多机器人监控系统,并开发了相应的协议和通信系统。该文主要介绍了它的系统结构、总线协议和相应的软件,并对性能进行了分析。

塔A和塔B地区古地温与热演化史研究

1）依据镜质组反射率（或由沥青、无定形干酪根换算成的镜质组反射率）拟合计算沉积盆地及生油层古地温是一种比较实用而又简便可行的方法。2）从十二口井井温数据分析，除X6井(2.0℃/100M)和X1井(2.05℃/100M)外，其它十口井的现地温梯度均小于2℃/100M。塔里木盆地的现地温梯度是较低的。3）拟合计算古地温的结果表明，塔B和塔A地区古地温梯度偏低半呈下降的趋势：塔B地区古生代隆起区古地温梯度为3.5℃/100M，凹陷区为3.0℃/100M，中生代古地温梯度为2.5-2.7℃/100M，新生代古地温梯度为2.0-2.2℃/100M。塔A及塔C地区：古生代隆起区的古地温梯度为3.5℃/100M，凹陷区为3.0℃/100M；中生代古地温梯度为2.5℃/100M，新生代为2.0-2.2℃/100M，今地温梯度为2.0℃/100M。4）古地温拟合计算结果表明：塔B地区志留系至二叠系地层基本被剥蚀，有的部位下古地层也遭到部分剥蚀。寒武-奥陶系总厚度在3000-4000米以上，生油层的生油期持续时间很长。寒武系底的生油期从寒武纪末到石炭纪（522-342Ma），目前普遍处在干气阶段。奥陶系底的生油期从奥陶纪末期一直持续到第三纪，90%的地区生油高峰期在泥盆纪末（早海西运动以后）之后（见图3-12），目前普遍处于凝析油-湿气阶段。塔A地区志留、泥盆系基本被剥蚀殆尽，而寒武-奥陶系基本未被剥蚀，总厚度在2000-4000米之间。寒武系底的生油期从寒武纪末期到泥盆纪（511-362Ma），至今大部分处于生气阶段。奥陶系底的生油期从泥盆纪一直到第三纪（404-40Ma），约30%的地区生油高峰期在泥盆纪末（早海西运动）之后（见图3-？），至今部分生油岩处于生气阶段。由于受加里东和海西运动的影响，塔A和塔B地区古生界地层普遍存在“二次生油”的现象。两地区石炭-二叠系一般在第三纪开始生油，生油期普遍较短。相对塔B和塔A地工而言，塔C地区受构造运动而遭剥蚀的程度要小得多。寒武-奥陶系总厚度范围为2100-8200米，因此生油层的生油期持续时间很长。寒武系底的生油期从中寒武世到石炭纪（536.5-305Ma）。奥陶系底的生油期从晚奥陶世一直到第三纪晚期（439.5-16.5Ma），仅少数地区生油高峰期在泥盆纪末（早海西运动）之后，目前大部分处于凝析油-湿气到干气阶段。石炭、二叠、三叠及侏罗系生油层目前大都处于“生油窗”内。总之，本区是塔A和塔B地区的主要油源区。5）通过对有机包裹体类型和荧光性质的鉴定、数量的统计、以及盐水溶液包裹体均一温度的测定，可以初步了解有机质热演化程度及含油气情况。6）对中生代样品，Tmax反映的成熟度与其它参数基本一致，而对于古生代样品，由于样品成熟度增大，Tmax失去指示成熟度的作用。原油和生油岩生物标志化合物反映的成熟度基本上与其它指标一致，因此在缺乏反射率资料的地区，可用生物标志化合物近似反映成熟度的变化。

Low temperature specific heat and thermal stability of Fe-B ultrafine amorphous alloy particles

Fe-B ultrafine amorphous alloy particles (UFAAP) were prepared by chemical reduction of Fe3+ with NaBHO4 and confirmed to be ultrafine amorphous particles by transmission electron microscopy and X-ray diffraction. The specific heat of the sample was measured by a high precision adiabatic calorimeter, and a differential scanning calorimeter was used for thermal stability analysis. A topological structure of Fe-B atoms is proposed to explain two crystallization peaks and a melting peak observed at T=600, 868 and 1645 K, respectively.

Perovskite-type B-site Bi-doped ceramic membranes for oxygen separation

Novel mixed conducting oxides, B-site Bi-doped perovskites were exploited and synthesized. Cubic perovskite structures were formed for BaBi0.2COyFe0.8-yO3-delta (y less than or equal to 0.4) and BaBixCo0.2Fe0.8-xP3-delta (x=0.1-0.5) The materials exhibited considerable high oxygen permeability at high temperature. The oxygen permeation flux of BaBi0.2Co0.35Fe0.45O3-delta membrane reached about 0.77 x 10(-6) mol/cm(2) s under an air/helium oxygen partial pressure gradient at 900 degrees C, which was much higher than that of other bismuth-contained mixed conducting membranes. The permeation fluxes of the materials increased with the increase of cobalt content, but no apparent simple relationship was found with the bismuth content. The materials also demonstrated excellent reversibility of oxygen adsorption and desorption. Stable time-related oxygen permeation fluxes were found for BaBi0.2CO0.35Fe0.45O3-delta and BaBi0.3Co0.2Fe0.5O3-delta a membranes at 875 degrees C.

Characterization and thermodynamic study of ultra-fine particle of Ni-B amorphous alloy

Ultra-fine particle of Ni-B amorphous alloy was prepared by chemical reduction of Ni2+ with NaBH4 and characterized with TEM and XRD. The heat capacity and thermal stability were measured with a high-precision automatic adiabatic calorimeter and DTA. The upper limit of applied temperature of the substance was found to be 684 K for use as catalyst. (C) 1999 Elsevier Science B.V. All rights reserved.