Investigations of the copper isotope effect in oxygen-deficient YBa2Cu3O7−δ

We present data on the copper isotope effect (⁶³Cu-⁶⁵Cu), C_u =-nT_c/nm_Cu, for two isotopic pairs of oxygen-deficient YBa₂Cu₃O_7–, where varies between 0.06 and 0.52. _Cu is below 0.01 at =0.06 (fully oxygenated), it takes values between –0.14 and –0.34 in the 60 K plateau. Larger negative values of _Cu are observed away from the plateau. The dependence of _Cu is similar to that of the pressure effect dnT_c/dP.     

ON THE ROBUST PREDICTION AND INTERPOLATION OF TIME SERIES IN THE PRESENCE OF CORRELATED NOISE

Abstract. We consider the problem of predicting and interpolating linearly a time series which can be represented as the sum of a model process with known spectral density and a noise process. The spectral density of the noise process is unknown with the exception of an upper bound for its integral. Some partial information of quite general kind about the cross spectral density of model and noise is available. We prove the existence of a robust predictor which minimizes the maximal mean-square error, where the maximum is taken over all spectral densities which may arise from the circumstances described above as spectral density of the predicted time series. An analogous result holds for the related interpolation problem. We describe how to derive the minimax robust predictor and interpolator in concrete situations. The method is illustrated by determining the robust predictor explicitly for three examples where model and noise may be arbitrarily, only causally or not at all correlated.     

Optimized in-phase and opposed-phase MR imaging for accurate detection of small fat or water fractions: theoretical considerations and experimental application in emulsions

Object  

To optimize strategies and measurement parameters for quantification of small fat and water fractions (<10%) in mixtures of both components by 4-point in-phase and opposed-phase gradient-echo imaging and to compare theoretical results with in-vitro experiments using emulsions.     

废电子电气产品塑料可持续再生过程中的能量回收(上)

故障现象：制冷正常，但制热时烧熔丝。分析与检测：该空调安装好后，试机时只试了制冷状态，制冷工作正常，却未进行制热试机。后来用户想试一下制热，拨到制热挡，熔断器一开机就跳闸，等合上闸后整机就无任何反应了。最初分析也许是巧合，检查主控板上的熔丝已经烧了，随即更换上了一块线路板，试机制冷正常，但在制热状态立刻烧熔断，判断制热存在严重短路现象。即然制冷正常，制热状态只多一个四通阀线圈用电，检查室外机的接线，原来是安装工错将三跟导线中的黄线接到了地上。     

Automated generation of program translation and verification tools using annotated grammars

Automatically generating program translators from source and target language specifications is a non-trivial problem. In this paper we focus on the problem of automating the process of building translators between operations languages, a family of DSLs used to program satellite operations procedures. We exploit their similarities to semi-automatically build transformation tools between these DSLs. The input to our method is a collection of annotated context-free grammars. To simplify the overall translation process even more, we also propose an intermediate representation common to all operations languages. Finally, we discuss how to enrich our annotated grammars model with more advanced semantic annotations to provide a verification system for the translation process. We validate our approach by semi-automatically deriving translators between some real world operations languages, using the prototype tool which we implemented for that purpose.     

An automatic braking system that stabilizes leukocyte rolling by an increase in selectin bond number with shear

Wall shear stress in postcapillary venules varies widely within and between tissues and in response to inflammation and exercise. However, the speed at which leukocytes roll in vivo has been shown to be almost constant within a wide range of wall shear stress, i.e., force on the cell. Similarly, rolling velocities on purified selectins and their ligands in vitro tend to plateau. This may be important to enable rolling leukocytes to be exposed uniformly to activating stimuli on endothelium, independent of local hemodynamic conditions. Wall shear stress increases the rate of dissociation of individual selectin-ligand tether bonds exponentially (, ) thereby destabilizing rolling. We find that this is compensated by a shear-dependent increase in the number of bonds per rolling step. We also find an increase in the number of microvillous tethers to the substrate. This explains (a) the lack of firm adhesion through selectins at low shear stress or high ligand density, and (b) the stability of rolling on selectins to wide variation in wall shear stress and ligand density, in contrast to rolling on antibodies (). Furthermore, our data successfully predict the threshold wall shear stress below which rolling does not occur. This is a special case of the more general regulation by shear of the number of bonds, in which the number of bonds falls below one.     

钢铁工业环境控制的现状及远景展望

刚刚迈进21世纪,往昔的国际或国内市场正在飞速发展为一个全球市场。环境保护也日益被人们看作是一个全球问题,即使在90年代早期Brundlandt委员会断言,人类有能力持续发展,当今和后代的需求都可以得到满足。钢铁工业愿意为持续发展作出自己的贡献。下面的报告将向我们展示环境保护在钢     

A single-chip Si-bipolar 1.6-GHz VCO with integrated-bias network

A single-chip 2.7-V voltage-controlled oscillator (VCO) with an integrated-bias network has been implemented in an Si-bipolar process with an f_T of 25 GHz. With an on-chip resonator consisting of vertically coupled inductors and varactor diodes, an oscillation frequency of 1.56 GHz was measured. A careful design of the oscillator and bias network was necessary to achieve a phase noise performance of -139 dBc/Hz at 4.7 h MHz off carrier. The tuning sensitivity was 100 MHz/V, which is sufficient to compensate for production tolerances. The VCO can be used as a building block for single-chip transceivers in digital European cordless telephone or global system for mobile communication systems     

An Adaptive Digital Front-End for Multimode Wireless Receivers

The ongoing evolution from 2G to 3G and beyond requires multimode operation of wireless cellular transceivers. This paper discusses the design of an adaptive wireless receiver for multimode operation and power efficiency. This is achieved by sharing digital signal processing stages for all operation modes and adapting them such that performance requirements are met at a minimum power consumption. The flexibility a digital front-end introduces in combination with an analog zero-intermediate-frequency receiver is studied with respect to the main cellular communication standards (Global System for Mobile Communication, Enhanced Data Rates for Global Evolution, Wide-Band Code-Division Multiple Access (WCDMA)/High-Speed Downlink Packet Access, and CDMA2000 and satellite navigation systems (Galileo), with considerations of impacts on the capability of an implementation of a software-defined radio. The proposed approach is verified by simulations exhibiting an error-vector magnitude of 2.9% in Universal Mobile Telecommunications System mode while the estimated power consumption can be reduced by 62% versus full featured mode at reasonable degradation in modulation quality.     

The wet corrosion of molybdenum thin film –. Part I: Behavior at 25°C

The corrosion and passivation behaviour of molybdenum thin films obtained by Physical Vapor Deposition (PVD) was investigated in aerated chloride and sulfate solutions at different pH values. Open circuit potential (ocp) measurements, polarisation experiments and electrochemical impedance spectroscopy (EIS) were employed. The experimental results suggest that the metal surface is covered by a passive film; however, corrosion still occurs. For the samples assessed during the current research, the acidic electrolytes tended to be less corrosive; however, a limited passive region was associated with the most basic sulfate or chloride solution. The effect of the pH was found to be more pronounced than the effect of the ion (chloride or sulfate).