基于多尺度空间划分与路网建模的城市移动轨迹模式挖掘

针对城市移动轨迹模式挖掘问题展开研究, 提出移动全局模式与移动过程模式相结合的挖掘方法, 即通过移动轨迹的起始位置点--终点位置点 (Origin-destination, OD点) 与移动过程序列分别进行移动全局模式与过程模式的发现. 在移动全局模式发现中, 提出了弹性多尺度空间划分方法, 避免了硬性等尺度网格划分对密集区域边缘的破坏, 同时增强了密集区域与稀疏区域的区分能力.在移动过程模式发现中, 提出了基于移动轨迹的路网拓扑关系模型构建方法, 通过路网关键位置点的探测抽取拓扑关系模型.最后基于空间划分集合与路网拓扑模型对原始 移动轨迹数据进行序列数据转换与频繁模式挖掘. 通过深圳市出租车历史 GPS 轨迹数据的实验结果表明, 该方法与现有方法相比在区域划分、数据转换等方面具有更好的性能, 同时挖掘结果语义更为丰富, 可解释性更强.     

基于改进APF-RRT的6R机械臂避障路径规划

针对6R机械臂在复杂环境下进行避障路径规划时成功率低、效率低等问题,提出一种改进人工势场法（APF）与快速扩展随机树法（RRT）的融合算法。对于传统APF目标不可达问题,提出引入斥力调节因子优化斥力函数,使得机械臂靠近目标点时,障碍物对机械臂的斥力逐渐减小并顺利到达目标点;针对传统RRT算法随机性过强问题,提出目标导向策略进行优化,使得采样点有一定的概率向目标点扩展;当APF陷入局部最优时,采用改进RRT算法进行路径规划,当跳出局部最优时,切换为APF继续路径规划。仿真结果表明：改进APF-RRT算法能适应各种复杂环境,且相较于传统APF和RRT算法具有规划时间短、规划成功率高等优点,有效解决了APF目标不可达和局部最小值的问题。最后通过 JAKA 机器人实验平台进行实际环境实验,验证了改进APF-RRT融合算法的可行性。     

半导体硅片制备技术及产业现状

介绍半导体硅片制备技术及理论，分析目前全球硅片的产业概况、产业历史发展趋势及特点；结合我国目前的实际情况，论述国内大力发展硅片产业面临的机遇、挑战及存在的问题。      

Traces of contamination–well preserved in honey

In our study, honey samples of different global and local origins were tested for antibiotic residues as well as the presence of the bacterium Paenibacillus larvae, the causative agent of the honeybee disease American foulbrood (AFB). 30 German and 47 imported non-European honeys were analyzed for sulfonamides, trimethoprim, tetracyclines, macrolides, lincomycin and chloramphenicol. 22 of the imported honeys contained residues (in most cases more than one), whereas 29 of the 30 German samples were free of residues. Sulfamethoxazole was the most frequently found antibiotic (often combined with trimethoprim). Almost all of the analyzed honeys from Argentina, China and Canada were AFB-positive (category I and II), whereas only five German honeys were AFB-positive. A correlation of present antibiotics and AFB spores was not found. For investigating putative relations between imported honeys and AFB cases in the area of Hamburg, genomic fingerprinting by PCR-amplification of repetitive DNA elements of the bacterial isolates was performed. The study shows that distinct genotypes of P. larvae are prevalent in samples of different geographical origin. AFB isolates of imported honeys differ from the predominant genotype in the area of Hamburg. Furthermore, the prevalent genotype in Hamburg was characterized by the absence of the iC9-fragment which was shown to be linked to virulence of P. larvae strains.     

基于全内反射的光束准直性检测新方法

准直光束是光学检验以及对光学仪器进行标定时最为常用的光束,光束自身的准直性是对光束性能评价的重要指标。本文提出了一种基于全内反射的检测方法,通过检测斜方棱镜发生两次全内反射后出射光斑的能量分布,判断待测光束的准直性,并利用缩束透镜提高检测灵敏度。分析讨论了影响该方法精度的因素,理论上估算出了检测精度。实验结果表明,该检...     

Intra-abdominal lymphangioma--clinicopathological profile of a rare lesion

Lymphangioma occurring in an intra-abdominal location is reported to be extremely rare. A series of 5 cases is presented and the differential diagnoses and diagnostic features discussed. None of the cases were diagnosed as lymphangioma clinically. It is suggested that their true incidence may be unknown due to both silent clinical course as well as lack of awareness of clinical and morphological features.     

Dual NF1-requiring effect of human neurotropic JC virus composite pentanucleotide repeat elements on early and late viral gene expression

OBJECTIVE: The purpose of this study was to prepare a light-cured adhesive applicable for orthodontics by mixing monomers and a polymerized reactive organic composite filler (prepolymerized trimethylolpropane trimethacrylate-filler, TMPT-filler). METHODS: The monomer component was a mixture of 3.0 wt% 2-hydroxy-3-(2-naphthoxy)propyl methacrylate (HNPM) in triethylene glycol dimethacrylate. This was applied to extracted bovine tooth enamel after acid etching with 65 wt% phosphoric acid for 30 s. After 24 h in 37 degrees C water, the tensile bond strength was measured, and the data were analyzed with Duncan's new multiple range test (p < 0.01 or 0.05). RESULTS: The tensile bonding strength to enamel etched with 65 wt% phosphoric acid was 13.1 +/- 0.5 MPa, and the thermal stability of the bond was excellent. SEM examination of the cross-sectioned specimens modified with HCl demineralization showed that when the diffusion time prior to light irradiation was only 1 min, a well-developed resin honeycomb-like structure was created in the enamel surface in the formulation containing HNPM. SIGNIFICANCE: Monomer impregnation beyond the etched enamel surface was important for resin-enamel bonding, increasing bonding strength and thermal stability. HNPM was effective in enhancing monomer diffusion and impregnation of the etched enamel surface.     

LOGNORMAL-NLSQ-technique. Evaluation of a new mathematical method for determining blood volume

This paper describes the investigation of a new mathematical method of calculating blood volume. The new method determines the blood volume by calculating the product of the mean circulation transit time. The mean transit time is calculated from the body transport function. To examine the accuracy of the LOGNORMAL-NLSQ technique, 45 concentration time curves were measured in an in vitro recirculation model with variable clearance. The calculated volume was 4% smaller than the actual volume. This may be attributed to the functional dead space within the model, and is tolerable for clinical situations. The LOGNORMAL-NLSQ technique might acquire considerable importance in future, especially since it provides accurate results very quickly.     

High serum lipoprotein(a) levels in Korean type 2 diabetic patients with proliferative diabetic retinopathy

OBJECTIVE: To examine the possible association between serum lipoprotein(a) [Lp(a)] concentration and proliferative diabetic retinopathy (PDR) in Korean patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: A total of 412 Korean outpatients with type 2 diabetes were examined. Diabetic retinopathy was determined by an ophthalmologist using fundoscopic examination. Serum Lp(a) levels were measured by two-site sandwich enzyme-linked immunosorbent assay. RESULTS: The patients with PDR had higher serum Lp(a) levels than those with no diabetic retinopathy or with nonproliferative diabetic retinopathy (NPDR). Multiple logistic regression analysis showed that high serum Lp(a) levels and the presence of diabetic nephropathy were independent variables having a statistically significant association with PDR. CONCLUSIONS: Korean type 2 diabetic patients with PDR had higher serum Lp(a) levels versus those with no diabetic retinopathy or with NPDR. Although these results suggest that Lp(a) might play a role in the occlusion of retinal capillaries leading to PDR, further prospective studies are required to prove the causal relationship.