2014年中国高性能计算机发展现状分析与展望

本文根据2014 年11 月发布的中国高性能计算机TOP100 排行榜的数据,对国内高性能计算机的发展现状从总体性能、制造商、行业领域等方面进行了深入分析。我们发现, 由于天河二号超级计算机的发布,中国TOP100 的平均Linpack 性能已经从两年前的落后一年变为比国际TOP500 平均Linpack 性能高的局面,且TOP100 的入门性能门槛也第一次超过TOP500。在此基础上,根据十三届排行榜积累的性能数据和能够得到的其他公开历史数据,对未来几年中国大陆高性能计算机的发展趋势进行了分析预测。根据新的数据和实际情况,经修正后我们认为,累计Linpack 性能将在2015 年到2016 年间达到100Petaflops, 比我们原来预期的晚;峰值100Petaflops 的机器将在2015 年到2016 年间出现;峰值Exaflops 的机器将在2019 年到2020 年间出现,比我们原来预期的晚2 年。单台机器峰值超过累计Linpack 性能的情况出现在2018 到2019 年间。     

Propagation Characteristics of kHz Band PLC Signal on MV–LV Distribution System

The kHz band power line communication (PLC) is one of the convincing mediums of the communication system for smart meter reading. Data transmission between medium‐voltage (MV) and low‐voltage (LV) points to pass the transformer by PLC is interested. In this paper, the PLC signal propagation characteristics between points of MV at substation and LV at customer are calculated and analyzed. The results show that direct communication between points on MV distribution line and most LV customers is impossible due to large propagation losses at MV–LV transformer and on LV distribution line.     

利用微机数据处理提高温度测量精度

本文讨论两种利用微机数据处理提高铂电阻温度传感器测量精度的修正算法.多通道温度数据采集器通过USB总线接口与计算机连接,温度传感器采用Pt100铂电阻,通过修正铂电阻的0(C电阻值R0、100(C与0(C电阻比值W100,有效提高温度测量精度,以达到使用廉价的B级Pt100铂电阻传感器,仍可获得较高的测量精度.     

Stabilization and Target Delivery of Nattokinase Using Compression Coating

ABSTRACT

The aim of the work is to develop a new formulation in order to stabilize a nutraceutical enzyme Nattokinase (NKCP) in powders and to control its release rate when it passes through the gastrointestinal tract of human. NKCP powders were first compacted into a tablet, which was then coated with a mixture of an enteric material Eudragit® L100-55 (EL100-55) and Hydroxypropylcellulose (HPC) by direct compression. The activity of the enzyme was determined using amidolytic assay and its release rates in artificial gastric juice and an intestinal fluid were quantified using bicinchoninic acid assay. Results have shown that the activity of NKCP was pressure independent and the coated tablets protected NKCP from being denatured in the gastric juice, and realized its controlled release to the intestine based on in vitro experiments.     

RETRACTED: Reproducibility study of (TLD-100) dosimeters using an automated and manual TLD reader for radiotherapy applications

The precision of the response of Harshow thermoluminescent dosimeters (TLD-100) is investigated for two Harshow TLD readers. The mean reproducibility for chips pre-readout annealed at 100 °C for 15 min, evaluated with the manual planchet reader 4500, is 0.61% (1 standard deviation) using pre-readout method. When chips are evaluated with the automated hot-gas reader 4500, reproducibility values are undoubtedly worse, mean reproducibility for numerically stabilized dosimeters being equal to 2.12%(1 standard deviation) using pre-readout method also. The pre-readout method was used for elimination of lower temperature peaks in order to obtain more stability. These results indicate that the automated hot-gas 4500 reader, or, at least, the instrument used for the present measurements, is not adequate for chips evaluation, if precise and accurate dosimetry is required. The difference in precision for manual planchet reader is apparently due to geometry inconsistencies in the orientation of the planchet to imperfect chips faces during readout, requiring careful and manual reproducible arrangement of the selected chips faces in contact with the manual reader planchet. In order to elucidate this point, the planchet support face of all chips dosimeters was identified with a small point made by pencil, reducing in this way geometrical variations.     

The influence of frequency on fractal dimension of adsorbed layers

Alternating current (AC) voltammetry and electrochemical impedance spectroscopy are often the methods of choice for use in study of adsorption of organic molecules. The adsorption of organic molecules on interface may result in the formation of fractal structures, whose fractal dimension can be estimated using the method of scaling the hanging mercury drop electrode (HMDE). The aim of present study was to check whether the estimated fractal dimension, D (or for that matter the fractal ordering of the adsorbed layer) shows any correlation (dependence) with change of applied frequency, and second, to check the possibility to extend the method to broad frequency spectrum compatible with impedance spectroscopy. The investigation included two surfactants nonionic Triton-X-100 (T-X-100) and anionic sodium dodecyl sulfate (SDS) and alcohol tert-butanol. All measurements were performed on HMDE at thermodynamic equilibrium employing broad frequency spectrum. The validity of the approach was checked by measurements on pure electrolyte and by comparison with previously obtained results for fractal layers. The results of the investigations show that: (1) the method of scaling the HMDE to obtain the fractal dimension of adsorbed layer is compatible with impedance spectroscopy and the combination of these methods can be used as a powerful tool to investigate fractal aspect of adsorption of organic molecules; (2) fractal ordering of adsorbed layer and the value of fractal dimension is not influenced by the frequency of applied sinusoidal voltage perturbations.     

新版百元币防伪特征与光学鉴别

本文从纸张、油墨、印刷等方面介绍了新版百元币的票面特征、设计特点，并运用配光、显微照相、特种照相等检验手段分析了该币的防伪特征，为鉴别真伪提供了科学依据。     

Scanned Probe Oxidation on p-GaAs(100) Surface with an Atomic Force Microscopy

Locally anodic oxidation has been performed to fabricate the nanoscale oxide structures on p-GaAs(100) surface, by using an atomic force microscopy (AFM) with the conventional and carbon nanotube (CNT)-attached probes. The results can be utilized to fabricate the oxide nanodots under ambient conditions in noncontact mode. To investigate the conversion of GaAs to oxides, micro-Auger analysis was employed to analyze the chemical compositions. The growth kinetics and the associated mechanism of the oxide nanodots were studied under DC voltages. With the CNT-attached probe the initial growth rate of oxide nanodots is in the order of ~300 nm/s, which is ~15 times larger than that obtained by using the conventional one. The oxide nanodots cease to grow practically as the electric field strength is reduced to the threshold value of ~2 × 10⁷ V cm⁻¹. In addition, results indicate that the height of oxide nanodots is significantly enhanced with an AC voltage for both types of probes. The influence of the AC voltages on controlling the dynamics of the AFM-induced nanooxidation is discussed.