44,021 research outputs found

    Self-consistent determination of the perpendicular strain profile of implanted Si by analysis of x-ray rocking curves

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    Results of a determination of strain perpendicular to the surface and of the damage in (100) Si single crystals irradiated by 250-keV Ar+ ions at 77 K are presented. Double-crystal x-ray diffraction and dynamical x-ray diffraction theory are used. Trial strain and damage distributions were guided by transmission electron microscope observations and Monte Carlo simulation of ion energy deposition. The perpendicular strain and damage profiles, determined after sequentially removing thin layers of Ar+-implanted Si, were shown to be self-consistent, proving the uniqueness of the deconvolution. Agreement between calculated and experimental rocking curves is obtained with strain and damage distributions which closely follow the shape of the trim simulations from the maximum damage to the end of the ion range but fall off more rapidly than the simulation curve near the surface. Comparison of the trim simulation and the strain profile of Ar+-implanted Si reveals the importance of annealing during and after implantation and the role of complex defects in the final residual strain distribution

    Singularity-matching peaks in superconducting single-electron transistor

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    We report the experimental observation of the recently predicted peaks on the I-V curve of the superconducting single-electron transistor at relatively high temperatures. The peaks are due to the matching of singularities in the quasiparticle density of states in two electrodes of a tunnel junction. The energy shift due to Coulomb blockade provides the matching at finite voltage.Comment: 11 pages (RevTeX), 3 figure

    Strain modification in coherent Ge and SixGe1–x epitaxial films by ion-assisted molecular beam epitaxy

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    We have observed large changes in Ge and SixGe1–x layer strain during concurrent molecular beam epitaxial growth and low-energy bombardment. Layers are uniformly strained, coherent with the substrate, and contain no dislocations, suggesting that misfit strain is accommodated by free volume changes associated with injection of ion bombardment induced point defects. The dependence of layer strain on ion energy, ion-atom flux ratio, and temperature is consistent with the presence of a uniform dispersion of point defects at high concentration. Implications for distinguishing ion-surface interactions from ion-bulk interactions are discussed

    An easy-to-use diagnostic system development shell

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    The Diagnostic System Development Shell (DSDS), an expert system development shell for diagnostic systems, is described. The major objective of building the DSDS is to create a very easy to use and friendly environment for knowledge engineers and end-users. The DSDS is written in OPS5 and CommonLisp. It runs on a VAX/VMS system. A set of domain independent, generalized rules is built in the DSDS, so the users need not be concerned about building the rules. The facts are explicitly represented in a unified format. A powerful check facility which helps the user to check the errors in the created knowledge bases is provided. A judgement facility and other useful facilities are also available. A diagnostic system based on the DSDS system is question driven and can call or be called by other knowledge based systems written in OPS5 and CommonLisp. A prototype diagnostic system for diagnosing a Philips constant potential X-ray system has been built using the DSDS

    The Effect of Infections on the Mortality of Cirrhotic Patients with Hepatic Encephalopathy

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    [[abstract]]Cirrhotic patients are prone to having infections, which may aggravate hepatic encephalopathy (HE). However, the effect of infections on mortality in HE cirrhotic patients is not well described. The National Health Insurance Database, derived from the Taiwan National Health Insurance Programme, was used to identify 4150 adult HE cirrhotic patients hospitalized between 1 January 2004 and 31 December 2004. Nine hundred and eighty-five patients (23.7%) had one or more co-existing infections during their hospitalization. After Cox proportional hazard regression modelling adjusted by the patients' gender, age, and medical comorbidity disorders, the hazard ratios (HRs) in HE patients with infections for 30-day, 30- to 90-day, and 90-day to 1-year mortalities were 1.66 [95% confidence interval (CI) 1.42-1.94], 1.51 (95% CI 1.23-1.85) and 1.34 (95% CI 1.13-1.58), respectively. Compared to the non-infection group, the HRs of pneumonia, spontaneous bacterial peritonitis, urinary tract infection, sepsis without specific focus (SWSF), cellulitis, and biliary tract infection were 2.11, 1.48, 1.06, 2.21, 1.06, and 0.78, respectively, for 30-day mortality; 1.82, 1.22, 0.93, 2.24, 0.31, and 2.82, respectively, for 30- to 90-day mortality; and 2.03, 0.82, 1.24, 1.64, 1.14, and 0.60, respectively, for 90-day to 1-year mortality for HE cirrhotic patients. We conclude that infections increase the mortality of HE cirrhotic patients, especially pneumonia and SWSF.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙本[[booktype]]電子

    Clinical Response and Autonomic Modulation as Seen in Heart Rate Variability in Mechanical Intermittent Cervical Traction: A Pilot Study

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    [[abstract]]OBJECTIVE: To determine the influence of mechanical intermittent cervical traction on the autonomic system. DESIGN: Prospective, cases series study. SUBJECTS: Sixteen healthy volunteers without contraindications for cervical traction. METHODS: Subjects received mechanical intermittent cervical traction in a sitting position under two traction forces (10% and 20% of total body weight). Electrocardiographic and neck surface electromyographic signals were recorded and analysed from 3 5-min periods (before, during and after traction). Subjective symptoms, heart rate and heart rate variability parameters, including standard deviation of all normal-to-normal beat intervals, very low-frequency power, low-frequency power, high-frequency power, multiscale entropy, slope of multiscale entropy, and root mean square value of electromyography amplitude were statistically compared. RESULTS: This pilot study showed that using 10% body weight traction force was more comfortable than using 20% body weight. Only subtle perturbation was noted in the autonomic system when using 20% body weight traction force. CONCLUSION: The response pattern of heart rate variability analysis in this pilot study provides some early information about individual discomfort in cervical traction. The autonomic modulation and the safety of cervical traction with other modality settings or in patients with neck pain require further study.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙
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