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排序方式: 共有239条查询结果,搜索用时 11 毫秒
81.
The performance of normals and schizophrenics on five selected levels of aspiration variables was evaluated for significant differences and examined in the light of Hausmann's earlier findings. The differences between the groups are analyzed. Hausmann's findings, however, could not be reproduced. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
82.
Jost M. Bona G.L. Buchmann P. Sasso G. Vettiger P. Webb D. 《Photonics Technology Letters, IEEE》1990,2(10):697-698
Optical storage applications for AlGaAs power lasers require single-mode laser operation and well-controlled beam divergence. For AlGaAs GRIN separate confinement heterostructure (GRINSCH) ridge lasers, these optical characteristics are sensitive to the precise ridge geometry of the laser. Directional reactive ion etching with Cl2 and in situ monitoring of the etch with highly attenuated laser interferometry provide the excellent process control required during formation of the ridge. The process is described, and results are presented for lasers that were fabricated using this technique 相似文献
83.
S. Lee D. Kim Y. Jin Y. Han Y. Desta M. D. Bryant J. Goettert 《Microsystem Technologies》2004,10(6-7):522-526
A micro corona motor was fabricated using a membraneless built-on X-ray mask. Sharp stator electrodes of this motor ionize air molecules and ionized charges transfer onto the rotor surface, resulting in rotating rotor motions by Coulomb forces. For good performance, the stators electrodes should be wide (axial) and have sharp tips. Therefore, X-ray lithography was adopted for precise, high aspect ratio characteristics. To avoid the fabrication difficulty of a membrane X-ray mask, a built-on X-ray mask (conformal mask) technique was employed with negative toned SU-8 photoresist. SU-8 features X-ray fabrication compatibility, X-ray transparency and a large range of thickness. This technique may be suitable for fast fabrication of prototypes or very tall structures, which can be largely affected by printing gaps. For the X-ray built-on mask, 20 m SU-8 was patterned and 8 m gold absorber was electroplated on top of the 300 m PMMA resist. Tests showed good quality pattern transfer from the SU-8 pattern and smooth sidewalls.The authors would like to thank the National Science Foundation, Grant DMI-0115527, Manufacturing Machines and Equipment Program, Division of Design, Manufacture, and Industrial Innovation, and Atoz CompuNet Ltd. for support for this work. We also acknowledge partial support from Center for Nano and Molecular Science and Technology and Welch foundation in The University of Texas at Austin. 相似文献
84.
Tryptic phosphopeptides from whole casein. II. Physicochemical properties related to the solubilization of calcium 总被引:2,自引:0,他引:2
R Berrocal S Chanton M A Juillerat B Pavillard J C Scherz R Jost 《The Journal of dairy research》1989,56(3):335-341
Casein phosphopeptides (CPP) were produced by tryptic hydrolysis of sodium caseinate and further purified by precipitation and chromatography on QAE-Sephadex A-25. Their physico-chemical properties were compared with the properties of an enzymically dephosphorylated equivalent preparation (DPP). Binding of Ca2+ to the peptides was measured using a Ca selective electrode and was found to increase with pH and to show 1/1 stoicheiometry Ca/Porg in CPP at pH 6.5 and 7.6. Klotz plots indicated equivalent binding sites at these two pH values, but some heterogeneity was seen at pH 3.5. In contrast, DPP did not bind significant amounts of Ca2+. CPP effectively inhibited the formation of insoluble calcium phosphates at different Ca/P ratios. The effective CPP concentration was 10 mg/l and complete stability of calcium phosphate solutions was obtained at about 100 mg/l. This stabilizing effect was dependent on the presence of organic P. 相似文献
85.
Yoo JI Shinagawa T Wood JP Linak WP Santoianni DA King CJ Seo YC Wendt JO 《Environmental science & technology》2005,39(13):5087-5094
Sorption of cesium and strontium on kaolinite powders was investigated as a means to minimize the emissions of these metals during certain high-temperature processes currently being developed to isolate and dispose of radiological and mixed wastes. In this work, nonradioactive aqueous cesium acetate or strontium acetate was atomized down the center of a natural gas flame supported on a variable-swirl burner in a refractory-lined laboratory-scale combustion facility. Kaolinite powder was injected at a postflame location in the combustor. Cesium readily vaporized in the high-temperature regions of the combustor, but was reactively scavenged onto dispersed kaolinite. Global sorption mechanisms of cesium vapor on kaolinite were quantified, and are related to those available in the literature for sodium and lead. Both metal adsorption and substrate deactivation steps are important, so there is an optimum temperature, between 1400 and 1500 K, at which maximum sorption occurs. The presence of chlorine inhibits cesium sorption. In contrast to cesium, and in the absence of chlorine, strontium was only partially vaporized and was, therefore, only partially scavengeable. The strontium data did not allow quantification of global kinetic mechanisms of interaction, although equilibrium arguments provided insight into the effects of chlorine on strontium sorption. These results have implications for the use of sorbents to control cesium and strontium emissions during high-temperature waste processing including incineration and vitrification. 相似文献
86.
S. Jost F. Hergert R. Hock J. Schulze A. Kirbs T. Voß M. Purwins M. Schmid 《Solar Energy Materials & Solar Cells》2007,91(7):636-644
In this article, we present results of a detailed real-time X-ray diffraction (XRD) study on the formation of CuInSe2 from electroplated precursors. The solid-state reactions observed during the selenisation of three different types of precursors are presented. The first type of precursors (I) consists of the nanocrystalline phases Cu2−xSe and InSe at room temperature, which react to CuInSe2 starting at 470 K. The second type of precursor (II) shows an inhibited CuInSe2 formation out of the initial phases Cu2−xSe and γ-In2Se3 starting at 400 K. The third precursor type (III) shows completely different selenisation behaviour. Starting from the intermetallic compound Cu11In9 and amorphous selenium, the formation of the binary selenides In4Se3 and CuSe is observed after the melting point of selenium at 494 K. After selenium transfer reactions, the compound semiconductor CuInSe2 is formed out of Cu2−xSe and InSe. This type (III) reaction path is well known for the selenisation of SEL precursors (stacked elemental layers of sputtered copper and indium and thermally evaporated selenium). 相似文献
87.
F. Sauter W. Fritz W. Jost W. Bischof F. Kuhn J. Algermissen W. Simonis E. C. Metschl H. H. Meinke F. W. Gundlach W. de Beauclair G. Hoch H. Rögener A. Garve H. W. Hahnemann Walter Schmidt W. Wilke 《Forschung im Ingenieurwesen》1962,28(2):65-68
Ohne Zusammenfassung
VDI 相似文献
88.
Constipation is very common in Parkinson's disease. It is still not known whether constipation is due to a slow transit of the colon or an outlet obstruction. We examined 25 patients (11 women, 14 men, mean age 62 years) with newly diagnosed idiopathic Parkinson's disease. All patients had typical clinical symptoms (with an average score of 11.4 points on the Webster scale); the diagnosis was confirmed by 18F-Dopa-PET. In all patients the colon transit time was measured with radioopaque markers. Pudendal nerve lesions were excluded by neurography of the pudendal nerve. Electromyography of the external anal sphincter was performed with concentric needle electrodes in the right and left lateral position. Colon transit time in the patients averaged 3.7 days, with pathologically prolonged transit (> 4 days) in 6 patients (24%). Four patients (16%) showed mild neurogenic changes on sphincter EMG (16%). In three other cases (12%) long duration and large amplitude of motor unit action potentials (MUAPs), and a reduced interference pattern during maximal voluntary effort indicated a severe neurogenic lesion. One patient presented with involuntary contractions of the external anal sphincter at rest, which increased during strain (anism). 相似文献
89.
GF Hamann D Sch?tzer-Klotz G Fr?hlig M Strittmatter V Jost G Berg M Stopp K Schimrigk H Schieffer 《Canadian Metallurgical Quarterly》1998,50(5):1423-1428
OBJECTIVE: The diagnosis of a patent foramen ovale (PFO) as a cause of stroke is of increasing interest especially in young (<45 years) patients. METHODS: We studied potential right-to-left shunting using transesophageal echocardiography (TEE) and bilateral transcranial Doppler sonography (TCD) of the middle cerebral artery (MCA) simultaneously in 44 patients. All patients were younger than age 45 years and suffered from an acute ischemic stroke or transient ischemic attack. Other possible etiologies were excluded. Echo contrast medium was injected in an alternating mode via antecubital or femoral veins. Tests were performed with and without the Valsalva maneuver. The criteria for a PFO were that the contrast pass from the right to the left atrium (TEE) and early detection (<10 seconds) of more than 10 micro air bubbles in at least one MCA by TCD. RESULTS: A PFO was diagnosed in 22 patients (50%). The detection rate with TEE/TCD was 11.4%/4.5% via antecubital injection, 18%/13.6% via antecubital injection plus the Valsalva maneuver, 38.6%/36% via femoral injection alone, and 50%/50% via femoral injection plus the Valsalva maneuver. The difference between femoral and antecubital injections was significant with and without the Valsalva maneuver (p < 0.01, chi2 test). There were no differences between TEE and TCD after femoral injection with the Valsalva maneuver. The brain transit time was 4.6 +/- 2.1 seconds for femoral injection and 6.3 +/- 4.1 seconds for antecubital injection. CONCLUSIONS: The sensitivity in detecting a PFO was markedly increased by femoral injection. This may be caused by different inflow patterns to the right atrium: inferior vena caval flow is directed to the right atrial septum, whereas superior vena caval flow is directed to the tricuspid valve. Thus, femoral injection may help to improve the detection of PFO and may explain the differences between TEE and TCD findings in previous studies. 相似文献
90.
Disorders of autonomic regulation are common in patients with Parkinson's disease (PD). Patients most frequently complain of dysphagia and therapy resistant constipation, as far as the gastrointestinal tract is concerned. These symptoms have to be attributed to a neuronal degeneration. In a pilot study we therefore investigated the effect of stimulation of the myenteric plexus by cisapride. 11 women and 13 men were examined, the average age was 67.3 years, the Webster rating 17 points. In 2 out of 24 patients, colonic transit was prolonged up to the limit, both with and without therapy. The other 22 patients showed an acceleration in transit on response to cisapride. On average the colonic transit of 130 hours was reduced to 79 hours. This objective improvement was associated with a subjective improvement. Central side effects or a worsening of Parkinsonian symptoms were not found. We conclude that cisapride is effective in the treatment of constipation in idiopathic PD. 相似文献