Computation of medial axis and offset curves of curved boundaries in planar domain

In this paper, we begin our research from the generating theory of the medial axis. The normal equidistant mapping relationships between two boundaries and its medial axis have been proposed based on the moving Frenet frames and Cesaro’s approach of the differential geometry. Two pairs of adjoint curves have been formed and the geometrical model of the medial axis transform of the planar domains with curved boundaries has been established. The relations of position mapping, scale transform and differential invariants between the curved boundaries and the medial axis have been investigated. Based on this model, a tracing algorithm for the computation of the medial axis has been generated. In order to get the accurate medial axis and branch points, a Two_Tangent_Points_Circle algorithm and a Three_Tangent_Points_Circle algorithm have been generated, which use the results of the tracing algorithm as the initial values to make the iterative process effective. These algorithms can be used for the computation of the medial axis effectively and accurately. Based on the medial axis transform and the envelope theory, the trimmed offset curves of curved boundaries have been investigated. Several numerical examples are given at the end of the paper.     

一种新的海洛因毒源判别方法及其软件使用

应用气质联用(GC/MS)分析方法,获得云南省9个地区缴获的1148个海洛因毒品样品中海洛因、单乙酰吗啡和乙酰可待因3种组分(记为A、B、c)的含量.在对数据做了一维、三维分布情况观察之后,提出一种"等高图"毒源判别模式.建成以地区归属的毒品数据库,并绘制分别用组分A、B、C为Z轴表示的各地区等高图.选择有毒源代表性的5个边境地区的15个等高图基础模式,编制出判别未知样品的毒源鉴定程序软件.对软件的使用过程、判别能力、升级没想也作了说明.     

云南花卉产业链支撑系统信息传输安全的实现

为促进云南省花卉产业升级,云南花卉产业链支撑系统应运而生,它是基于B／S模式的,大量花卉产业链上的企业在使用时其管理信息以及用户密码信息借助网络在Browser和Web Server之间传输,由于Browser和Web Server之间通信时所使用的HTTP协议存在安全隐患,因此从信息安全的角度,分析讨论了数据加密技术、SSL协议的基本原理,并为云南花卉产业链支撑系统的Web信息传输安全给出了完整的解决方案。     

一种基于功率谱重心的自适应特征信息提取方法

提出一种基于功率谱重心的自适应特征信息提取方法.该方法通过对不同状态转换过程中的灵敏度分布进行分析获得特征功率谱,然后计算特征功率谱的重心频率以及自适应加权系数,对特征功率谱进行自适应加权计算获得特征信息.文中给出了将自适应特征信息提取方法应用于磨煤机噪声信号特征提取的实例,对比分析了采用不同特征信息提取方法的效果.仿真结果表明,所提出的自适应特征信息提取方法能够准确剔除无效信息,自主适应运行工况变化,具有较好的灵敏度和线性度,为提高软测量模型的预测精度和泛化性能提供了保证.     

高校网络教育资源建设探讨

网络教育资源建设是高校教育信息化建设的一个重要方面,许多高校已经具有自己的网上教学资源。但纵观目前高校网络教育的建设现状,普遍存在缺乏整体规划、未能形成完整多功能的系统、各方面结合较松散等问题。本文针对这些问题,进行了深入的分析,探讨了这些问题存在的原因,借鉴国内外资源建设的成功经验并结合计算机方面的技术知识,探索适合本国发展的对策为给高校网络教育建设打好坚实的基础,提出了一套系统规划与建设的方案。     

Thermal efficiency of manifold-heat-pipe heat exchangers

The thermal efficiency of manifold-heat-pipe heat exchangers is considered. A method for predicting the efficiency and an analysis of effects of various factors of the actual process are presented.Academic Scientific Complex A. V. Luikov Heat and Mass Transfer Institute of the Academy of Sciences of Belarus, Minsk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 66, No. 2, pp. 173–178, February, 1994.     

Microstructure of sputtered epitaxial Ni0.80Fe0.20/NixCO1−xO exchange coupled bilayers on α-Al2O3 (0001)

Epitaxial Ni_0.80Fe_0.20/Ni_xCo_1−xO bilayers have been grown on α-Al₂O₃ (0001) substrates by dc-sputtering X-ray diffraction and transmission electron microscopy have been employed to characterize these exchange-coupled films. The x-ray diffraction spectrum shows only the (111) family of peaks in both Ni_0.80Fe_0.20 and Ni_xCO_1−xO films. Growth orientation relationships have been determined from diffraction patterns taken in planar view and cross section. The relationships are: (111) Ni_0.80Fe_0.20//(111) Ni_xCo_1−xO//(0001) α−Al₂O₃ and [1 0]Ni_0.80FE_0.20//[1 0]Ni_xCo_1-xO//[1 00] α-Al₂O₃. The microstructure of these films as well as the interfacial structure between Ni_0.80Fe_0.20 and Ni_xCo_1−xO have been analyzed in high resolution electron microscopy and are described in this paper. In addition, the dependence of the exchange coupling field on interfacial roughness is discussed.     

Effects of double-muscling on carcass quality, beef tenderness and myofibrillar protein degradation in Belgian Blue White bulls

Carcass properties and meat quality characteristics of 32 Belgian Blue White double-muscled bulls (DM) were compared with those of 59 bulls of the same breed with normal conformation (N). DM showed superior carcass quality as revealed in increased dressing percentage, meat production yield, conformation grade, muscle/fat and muscle/bone ratios (all P < 0·001). Longissimus dorsi (LD) shear force values, drip and cooking losses at 8 days post mortem (pm) were significantly higher (P < 0·001) for DM, whereas sarcomere lengths were not different. Calpain 1 and calpastatin levels at 1 h and 24 h pm were tremendously decreased in DM as were also cathepsin B and L levels at 1 and 8 days pm (P < 0·001). As evident from semi-quantitative SDS-PAGE, these differences were accompanied by higher titin and lower 30 kDa levels (P < 0·001) in DM. Troponin-t levels were not different, but very low. Intramuscular collagen content was significantly lower in DM (P < 0·001). This suggests that lower background toughness in DM was compensated for by reduced post-mortem proteolytic tenderization. Discrepancy with literature reports regarding tenderness of DM might be related to the extreme muscularity of the Belgian Blue White breed, compared to other DM breeds. The results also suggest that reduced protein turnover might be involved in the muscle hypertrophy phenomenon within this breed, because of likely reduced levels of calpains and cathepsins in living DM animals.     

Actual daily dietary intake of selenium in Belgium, using duplicate portion sampling

The dietary selenium (Se) intake in Belgium has been re-evaluated. Duplicate meal collection, wet acid destruction and flow injection hydride generation atomic absorption spectrometry were used as techniques. The daily intake ranged from 28.4 g (Liège, Walloon part of the country) to 61.1 g (Vilvoorde, central part of the country). Compared with intakes recently published for other countries, the actual Belgian value corresponds to intermediate ranges of Se intake.

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Die aktuelle tägliche Selen-Aufnahme durch die Nahrung in Belgien, bestimmt durch doppelte Probenahme

Zusammenfassung Die Selen-Aufnahme durch die Nahrung in Belgien wurde neu bestimmt. Als Technik diente die doppelte Probenahme von Mahlzeiten, deren nasser Aufschluß und die Fließ-Injektions AAS mit Hydridgeneration. Die tägliche Aufnahme schwankt zwischen 28,4 und 61, 1 g. Im Vergleich zu Daten, die neuerdings aus anderen Ländern publiziert wurden, liegen die derzeitigen Werte aus Belgien im Mittelbereich.