Dynamical considerations of network properties

Elasticity is discussed as an aspect of viscoelasticity, which is described by the tube model. The effects of both crosslinks and entanglements contribute to this model and a discussion of how these effects can be quantified is given. At high enough concentration, entanglements ensure the existence of elastic effects even without crosslinks, and a theory is presented on how this dynamical phase change comes about.     

Constant stretching rate experiments on low density polyethylene

A simple apparatus for elongational test of molten polymers is presented. Its realiability is demonstrated by means of stress growth in constant stretching rate experiments and relaxation test on a low density polyethylene sample.     

Seasat over-land scatterometer data. I. Global overview of theKu-band backscatterer coefficients

Statistics on the backscatter coefficient σ⁰ from the Ku-band Seasat-A Satellite Scatterometer (SASS) collected over the world's land surfaces are presented. This spaceborne scatterometer provided data on σ⁰ between latitude 80° S and 80° N at incidence angles up to 70°. The global statistics of vertical (V) and horizontal (H) polarization backscatter coefficients for 10° bands in latitude are presented for incidence angles between 20° and 70° and compared with the Skylab and ground spectrometer results. Global images of the time-averaged V polarization σ⁰ at a 45° incidence angle and its dependence on the incidence angle are presented and compared to a generalized map of the terrain type. Global images of the differences between the V an H polarization backscatter coefficients are presented and discussed. The most inhomogeneous region, which contains the deserts of North Africa and the Arabian Peninsula, is studied in greater detail and compared with the terrain type     

Evolutionary algorithms and de novo peptide design

One of the goals of computational chemistry is the automated de novo design of bioactive molecules. Despite significant progress in computational approaches to ligand design and efficient evaluation of binding energy, novel procedures for ligand design are required. Evolutionary computation provides a new approach to this design issue. This paper presents an automated methodology for computer-aided peptide design based on evolutionary algorithms. It provides an automatic tool for peptide de novo design, based on protein surface patches defined by user. Regarding the restrictive constrains of this problem a special emphasis has been made on the design of the evolutionary algorithms implemented.     

CONTOP(R)--钢铁工业和报废汽车处理业的经济回收方案

1 前言 CONTOP~R工艺最初是由德国科隆的KHDHumboldt Wedag AG公司针对有色金属工业而开发的。两台迄今为止最大的CONTOP~R熔炼旋风炉建于美国德克萨斯的ASARCO公司,每台能力为32t/h铜精矿混和料。 1998年,奥钢联工程技术公司(VAI)获得了     

Development of the Chinese Scientometric Indicators (CSI)

We describe the Chinese Scientometric Indicators (CSI), an indicator database derived from the Chinese Science Citation Database (CSCD). Its design is supported by the Natural Sciences Foundation of China (NSFC). In this indicator database data of a statistical nature are organized and categorized leading to ranked lists and providing bases for comparisons among Chinese institutions and regions.     

Microwave signal generation using an optical self-heterodyne technique

A new technique for mixing optical waves to generate microwave-frequency signals using an injection laser diode and a fibre-optic interferometer is reported. A beat signal is produced by interfering light from the laser with light from the same laser emitted earlier at a different frequency. The interferometer consists of an evanescent-field fibre coupler joined to a length of single-mode optical fibre. The laser is tuned by pulsed or bipolar current waveforms superimposed on a DC bias current. Feedback from an external cavity stabilises the laser frequency and reduces its linewidth. Efficient mixing at difference frequencies from 250 MHz to 2 GHz is obtained, with spectral widths of less than 1% of the centre frequency.     

Pulse-stream VLSI neural networks mixing analog and digitaltechniques

The pulse-stream technique, which represents neural states as sequences of pulses, is reviewed. Several general issues are raised, and generic methods appraised, for pulsed encoding, arithmetic, and intercommunication schemes. Two contrasting synapse designs are presented and compared. The first is based on a fully analog computational form in which the only digital component is the signaling mechanism itself-asynchronous, pulse-rate encoded digital voltage pulses. In this circuit, multiplication occurs in the voltage/current domain. The second design uses more conventional digital memory for weight storage, with synapse circuits based on pulse stretching. Integrated circuits implementing up to 15000 analog, fully programmable synaptic connections are described. A demonstrator project is described in which a small robot localization network is implemented using asynchronous, analog, pulse-stream devices.     

Measurement of the delayed-neutron yields in the fission of233U,236U,237Np,240Pu,and241Pu by neutrons from the spectrum of a fast reactor

Translated from Atomnaya Énergiya, Vol. 66, No. 2, pp. 100–103, February, 1989.