基于视图特征点分布的三维模型检索算法

已有的特征描述符所需存储空间大和匹配计算效果不理想,因此难以得到良好的检索效果． 针对这一问题,算法提出了一种结合ＢｏＦ和视图特征点分布的三维模型检索算法．算法首先用 ＳＩＦＴ描述符对模型渲染视图进行特征点提取和描述,然后运用ＢｏＦ算法对得到的ＳＩＦＴ特征描述 符进行简化,统计特征分布并得到其特征分布直方图,从而使得到的新的特征描述符能大大减少存 储空间,同时方便对模型相似性计算,最后通过三维模型数据库对算法进行统计分析．实验结果表 明所得到的新的特征描述符在检索效率上要优于传统的三维模型特征描述符．     

一种基于Ａｎｄｒｏｉｄ智能手机的车载定位查询软件

为实现在Ａｎｄｒｏｉｄ智能手机上对远程车载设备的定位查询,设计了一种基于Ａｎｄｒｏｉｄ的车载 定位查询软件．提出了一种车载定位查询系统框架,采用会话初始化协议作为系统的通信协议．在 拓展会话初始化协议的基础上,在该系统中设计了一种车载定位设备的定位信息上传和查询机制． 阐述了Ａｎｄｒｏｉｄ定位查询客户端软件的设计,客户端通过会话初始化协议实现了手机客户端的登 录、定位设备列表的获取和定位信息的查询,并使用Ｇｏｏｇｌｅ地图服务将车载定位设备的定位信息 标记在地图上．     

Compatibility studies on some polymer blend systems by electrical and mechanical techniques

Systematic electrical and mechanical studies were carried out on natural rubber (NR) blended with different types of synthetic rubber such as styrene‐butadiene rubber (SBR), polybutadiene rubber (BR), and ethylene‐propylene‐diene monomer (EPDM) as nonpolar rubbers and nitrile‐butadiene rubber (NBR) and chloroprene rubber (CR) as polar rubbers. The NR/SBR, NR/BR, NR/EPDM, NR/NBR, and NR/CR blends were prepared with different ratios (100/0, 75/25, 50/50, 25/75, and 0/100). The permittivity (ε′) and dielectric loss (ε″) of these blends were measured over a wide range of frequencies (100 Hz–100 kHz) and at room temperature (∼ 27°C). The compatibility results obtained from the dielectric measurements were comparable with those obtained from the calculation of the heat of mixing. These results were confirmed by scanning electron microscopy and showed that NR/SBR and NR/BR blends were compatible while NR/EPDM, NR/NBR, and NR/CR blends were incompatible. To overcome the problem of phase separation (incompatibility) between NR and EPDM, NBR, or CR, a third component such as SBR or poly(vinyl chloride) (PVC) was added as a compatibilizing agent to these blends. The experimental data of dielectric and mechanical measurements showed that the addition of either SBR or PVC could improve the compatibility of such blends to some extent. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 60–71, 2001     

Ce3+-doped LaF3 nanoparticles: Wet-chemical synthesis and photo-physical characteristics “optical properties of LaF3:Ce nanomaterials”

The most effective process parameters were determined to synthesize spherical LaF₃ nanoparticles with controllable size based on ethylenediaminetetraacetic acid (EDTA) via co-precipitation technique. Thermogravimetricdifferential thermal analysis, X-ray diffraction, scanning electron microscopy, dynamic light scattering and FT-IR spectroscopy were used to characterize the resulting powders. Detailed investigations revealed that the optimal LaF₃ host nano-material was obtained when NH₄F was used as a fluoride source in the presence of EDTA at pH = 5. Furthermore, photoluminescence spectra showed an intense double emission peak at 289 and 302 nm for cerium-doped LaF₃ nanocrystals excited at 253 nm, which was assigned to the well-known 5d→4f (²F_5/2 and ²F_7/2) transitions of Ce³⁺ levels due to luminescence center mechanism. The experimental results indicate that the synthesized LaF₃:0.05Ce powders with a band gap of 5.3 eV are promising phosphors for high density scintillators.     

Preparation and characterization of blends containing natural and some synthetic rubbers with synthesized aromatic polyester

This work deals with the synthesis of aromatic polyester (AP) from polyarylate [Bisphenol A (BPA)/dimethyl terephalate (DMT)/ethylene glycol (EG)] and maleic anhydride (MA) in presence of dibutyl tin oxide (DBTO) as a catalyst. Blends were prepared from candidated AP (10–30 phr) with different types of rubber [natural rubber (NR), acrylonitrile butadiene rubber (NBR), styrene butadiene rubber (SBR) and ethylene‐propylene‐diene monomer (EPDM)]. The obtained blends were subjected to physicomechanical measurements to evaluate their properties as efficient blends for economic industrial applications. In case of AP blended with rubber, better properties were obtained than that of rubber vulcanizates. The fatigue life values decreases by increasing the AP contents for all types of the tested blends. The equilibrium swelling (%) for the prepared blends exhibits different behavior in solvents like toluene and motor oil. The addition of N‐isopropyl‐N′‐phenyl‐p‐phenylene diamine (IPPD), as antioxidant, affects the properties of all the prepared products. These properties were in consequent with the data of the initial shear modulus, which is calculated from the Mooney‐Rivlin equation and the percentage of the equilibrium swelling. Scanning electron microscope (SEM) was used to study the morphological structure; the SEM results show the changes in surface of the rubber before and after being blended with AP. The investigated blends are considered a new trend in giving products with variable physicomechanical characteristics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

永存三叉动脉伴发脑血管性病变及其他脑部疾病

永存三叉动脉（PPTA）是成人最常见的一种永久性颈内动脉和基底动脉之间的异常吻合，是一种较罕见的脑血管变异。PPTA经常伴发脑血管性病变，并且可引起三叉神经痛，动眼神经、外展神经麻痹，蛛网膜下腔出血等症状，与临床关系较为密切。本文对１９８３年至今中英文文献报道的１１６例PPTA伴发脑血管性病变及其他脑部疾病的病例进行总结。     

特殊动脉导管未闭的介入治疗

目的分析特殊动脉导管未闭（PDA）的介入治疗方法，提高介入封堵的成功率及安全性。方法根据造影显示PDA形态及临床特点，选用合适封堵器和治疗方法，术后２４h、１、３、６个月时以心脏超声随访评价疗效。结果特殊类型PDA２３例，其中:①形态特殊型１２例，包括细小型５例，４例成功，１例５F导管无法通过PDA放弃介入治疗；粗大型３例；动脉瘤型２例；特殊投照体位２例，均成功封堵。②合并其他畸形２例:合并右位主动脉弓１例，合并右位心１例，均成功封堵。③合并重度肺动脉高压８例，６例成功。④外科术后再通１例，未封堵。结论特殊PDA采取不同的诊疗策略，大多可顺利完成介入封堵术     

靶血管内留置导管持续化疗患者的护理

目的减少保留导管持续化疗患者留置导管期间的相关问题的发生。方法①加强对患者的宣教、指导；②规范护士护理操作；③制定合理的护理常规、流程；④护士要加强日常护理中的观察、巡视、记录。结果通过对留置导管患者的各种问题的分析及临床观察，总结了护理经验。结论合理、有效的护理可以减少留置导管持续化疗患者留置导管期间相关问题的发生。     

围肝移植并发症介入治疗的认识

大部分肝移植术后并发症与介入放射学有关。动脉和静脉并发症有较明确的介入治疗模式，胆道并发症一直是治疗的重点和难点。随着对介入放射学认识的深入和操作技术的提高，在经皮经肝胆道引流、内镜鼻胆管引流基础上围绕胆道并发症进行的系列治疗，能解决部分患者的黄疸并最终治愈，但对另一些患者胆道引流仍是主要的姑息性治疗手段，并将最终伴随患者一生。围绕胆道并发症制订肝移植术后并发症的临床治疗指引是亟需解决的课题。     

CT引导下 １２５ I放射性粒子植入治疗肝癌门静脉癌栓的疗效评价

目的探讨CT引导下 １２５ I放射性粒子植入联合肝动脉化疗栓塞术（TACE）治疗肝癌合并门静脉癌栓（PVTT）的疗效。方法回顾性分析原发性肝癌合并PVTT患者５８例,A组（２６例）行TACE结合CT引导下 １２５ I放射性粒子植入局部放射治疗;B组（３２例）单纯行TACE。对比两组疗效。结果A组１、２年生存率分别为４２．３％、２３．０％,平均生存期１５．５个月,完全缓解（CR）３例,部分缓解（PR）９例,总有效率（CR＋PR）为４６．２％（１２／２６）。B组１、２年生存率分别为２１．９％、６．３％,平均生存期７．５个月CR２例,PR６例,CR＋PR为２５．０％（８／３２）。A组的生存率及总有效率显著高于B组（P＜０．０５）。结论TACE联合CT引导下 １２５ I放射性粒子植入治疗肝癌门脉癌栓能明显提高其疗效,并具有创伤少,并发症少等优点。