The heater test at the Grimsel Rock Laboratory: The thermo-mechanical response of the rock mass to a heat flux

The Grimsel Test Site (Felslabor Grimsel — FLG) is situated at a depth of 450 m in the Juchlistock massif of the Bernese Oberland. It is managed by the National Cooperative for the Storage of Radioactive Waste (NAGRA-Switzerland).By means of a heater test, the power output of canisters filled with high-level waste is simulated. This heater test is performed by the German Gesellschaft für Strahlen- und Umweltforschung — GSF. Two electrical heaters, with a heatable length of 6 m, a diameter of 0.3 m and an available power of 4 kW/m, are installed in two vertical boreholes. One of them is located in the granite adjacent to a strongly fractured lamprophyre vein, the other one directly within this disturbed zone. They are operating since August 1986.The thermo-mechanical reaction of the rock mass is registered by a large number of measurement devices which are installed in an array of instrument boreholes around the heaters. They record the deformation and the alteration of rock stresses, the pore water pressure and the water conductivity caused by heating.     

Operation of an experimental facility for fabrication of fuel elements and fuel assemblies of the bor-60 containing vibrocompacted fuel

Translated from Atomnaya Énergiya, Vol. 67, No. 5, pp. 320–323, November, 1989.     

A transmit/receive IF chip set for WCDMA mobiles in 0.35 /spl mu/m CMOS

An implementation of the IF section of WCDMA mobile transceivers with a set of two chips fabricated in an inexpensive 0.35-/spl mu/m two-poly three-metal CMOS process is presented. The transmit/receive chip set integrates quadrature modulators and demodulators, wide dynamic range automatic gain control (AGC) amplifiers, with linear-in-decibel gain control, and associated circuitry. This paper describes the problems encountered and the solutions envisaged to meet stringent specifications, with process and temperature variations, thus overcoming the limitations of CMOS devices, while operating at frequencies in the range of 100 MHz-1 GHz. Detailed measurement results corroborating successful application of the new techniques are reported. A receive AGC dynamic range of 73 dB with linearity error of less than /spl plusmn/2 dB and spread of less than 5 dB for a temperature range of -30/spl deg/C to +85/spl deg/C in the gain control characteristic has been measured. The modulator measurement shows a carrier suppression of 35 dB and sideband/third harmonic suppression of over 46 dB. The core die area of each chip is 1.5 mm/sup 2/.     

AlGaN/GaN HEMTs-an overview of device operation and applications

Wide bandgap semiconductors are extremely attractive for the gamut of power electronics applications from power conditioning to microwave transmitters for communications and radar. Of the various materials and device technologies, the AlGaN/GaN high-electron mobility transistor seems the most promising. This paper attempts to present the status of the technology and the market with a view of highlighting both the progress and the remaining problems.     

Can heat pipes solve the problems of drift and vibration of cryoholders?

Drift and vibration are the main factors limiting the resolution that can be attained with liquid-nitrogen (LN₂)-cooled cryoholders. Tests with a Gatan holder show that resolution is usually anisotropic. We propose that the metallic heat-conducting element could be replaced by a heat pipe, because such a device can, in principle, minimize drift. The vibration problem could be combatted by using supercooled cryogens.     

Si/SiGe n-MODFETs on thin SiGe virtual substrates prepared by means of He implantation

Si/SiGe n-type modulation-doped field-effect transistors grown on a very thin strain-relieved Si/sub 0.69/Ge/sub 0.31/ buffer on top of a Si(100) substrate were fabricated and characterized. This novel type of virtual substrate has been created by means of a high dose He ion implantation localized beneath a 95-nm-thick pseudomorphic SiGe layer on Si followed by a strain relaxing annealing step at 850/spl deg/C. The layers were grown by molecular beam epitaxy. Electron mobilities of 1415 cm/sup 2//Vs and 5270 cm/sup 2//Vs were measured at room temperature and 77 K, respectively, at a sheet carrier density of about 3/spl times/10/sup 12//cm/sup 2/. The fabricated transistors with Pt-Schottky gates showed good dc characteristics with a drain current of 330 mA/mm and a transconductance of 200 mS/mm. Cutoff frequencies of f/sub t/=49 GHz and f/sub max/=95 GHz at 100 nm gate length were obtained which are quite close to the figures of merit of a control sample grown on a conventional, thick Si/sub 0.7/Ge/sub 0.3/ buffer.     

Blind adaptive interference suppression for direct-sequence CDMA

Direct sequence (DS) code division multiple access (CDMA) is a promising technology for wireless environments with multiple simultaneous transmissions because of several features: asynchronous multiple access, robustness to frequency selective fading, and multipath combining. The capacity of DS-CDMA systems is interference-limited and can therefore be increased by techniques that suppress interference. In this paper, we present developments in interference suppression using blind adaptive receivers that do not receive knowledge of the signal waveforms and propagation channels of the interference, and that require a minimal amount of information about the desired signal. The framework considered generalizes naturally to include additional capabilities such as receive antenna diversity. The most powerful application of the methods described here is for linearly modulated CDMA systems with short spreading waveforms (i.e., spreading waveforms with period equal to the symbol interval), for which they provide substantial performance gains over conventional reception. Implications for future system design due to the restriction of short spreading waveforms and directions for further investigation are discussed     

Spinal reflex pattern to foot nociceptive stimulation in standing humans

We describe here the results of a screening program conducted to discover inhibitors of the type-I interleukin-1 receptor (IL-1RI) from samples of microbial origin. An innovative approach, based on automated, nonradioactive receptor binding assays has been employed. Specially prepared cell-free systems have allowed the use of high concentrations of microbial metabolites in the reaction mixtures with a low percentage of false positives. More than 30,000 microbial samples from different species of soil isolates have been tested and two interesting activities have been purified and characterized. One of these, isolated from Streptomyces sp. GE48009, was identified as niphimycin, an antifungal agent also known as scopafungin. Preliminary evidence suggests that this molecule and azalomycin F, a structural analogue, inhibit IL-IRI by virtue of their long-chain guanidinium moiety. The other activity, isolated from Aspergillus sp. GE49752, was identified as flavipin, a substituted o-phthalaldehyde.     

Expression of a functional tagged human thyrotropin receptor in HeLa cells using recombinant vaccinia virus

The aim of the present study was to assess the prognostic relevance of relatives' interactive behaviour towards the patient, as covered by the Münster Family Interview (MFI), to the further course of the schizophrenic illness. The MFI is a family interview (of the whole family, including the patient) designed to record the emotional family atmosphere based on the concept of expressed emotion (EE). The ratings take place directly after the interview on five scales (criticism, hostility, overinvolvement, resignation and warmth), the resignation scale being added to the 'classic' EE scales. Ninety-nine families of outpatients diagnosed with schizophrenia according to the DSM-III were examined with the MFI during a home visit. The patients were seen 1 and 2 years after the first examination. The target criteria selected for the prognostic significance of the interaction measurements were: rehospitalisation within 2 years; extent of symptoms after 1 year, and psychosocial skills after 1 year. The significance of the interaction dimensions was verified in regression models. The control variable used in the regression models was the Strauss-Carpenter scale. Regression models were produced for the total group and for a subgroup of moderately ill patients. All target criteria yielded serviceable prediction models. The most important variable for prediction was the control variable, the Strauss-Carpenter scale. However the interaction variables made additional contributions to the prognosis, especially in the subgroup of moderately ill patients. The best MFI scale for all the outcome criteria was resignation; criticism predicted only the symptomatology, and emotional overinvolvement the level of social functioning after 1 year. In conclusion, practical work with families of schizophrenic patients should emphasise the protective function of relatives towards patients more strongly.