This research project sought to design and implement a computerized clinical decision support system (CDSS) that was able to identify patients who were at risk of pulmonary embolism (PE) and deep vein thrombosis (DVT), as well as produce reminders for prophylactic action for these diseases. The main purpose of the CDSS was to attempt to reduce the morbidity and mortality caused by embolism and thrombosis in patients admitted to hospitals. After implementation of this system in one of the large educational hospitals of Iran, a standard questionnaire was used, and interviews were conducted with physicians and nurses to evaluate the performance of the designed system for reducing the incidence of pulmonary embolism and thrombosis. From physicians and nurses’ point of view, a system which assists the medical staff in making better decisions regarding patient care, and also reminds pulmonary embolism and thrombosis preventive procedures with timely warnings, can influence patient care quality improvement and lead to the improved performance of the medical staff in preventing the incidence of pulmonary embolism and thrombosis. 相似文献
Piezoelectric materials have dominated the ultrasonic transducer technology. Recently, capacitive micromachined ultrasonic transducers (CMUTs) have emerged as an alternative technology offering advantages such as wide bandwidth, ease of fabricating large arrays, and potential for integration with electronics. The aim of this paper is to demonstrate the viability of CMUTs for ultrasound imaging. We present the first pulse-echo phased array B-scan sector images using a 128-element, one-dimensional (1-D) linear CMUT array. We fabricated 64- and 128-element 1-D CMUT arrays with 100% yield and uniform element response across the arrays. These arrays have been operated in immersion with no failure or degradation in performance over the time. For imaging experiments, we built a resolution test phantom roughly mimicking the attenuation properties of soft tissue. We used a PC-based experimental system, including custom-designed electronic circuits to acquire the complete set of 128 x 128 RF A-scans from all transmit-receive element combinations. We obtained the pulse-echo frequency response by analyzing the echo signals from wire targets. These echo signals presented an 80% fractional bandwidth around 3 MHz, including the effect of attenuation in the propagating medium. We reconstructed the B-scan images with a sector angle of 90 degrees and an image depth of 210 mm through offline processing by using RF beamforming and synthetic phased array approaches. The measured 6-dB lateral and axial resolutions at 135 mm depth were 0.0144 radians and 0.3 mm, respectively. The electronic noise floor of the image was more than 50 dB below the maximum mainlobe magnitude. We also performed preliminary investigations on the effects of crosstalk among array elements on the image quality. In the near field, some artifacts were observable extending out from the array to a depth of 2 cm. A tail also was observed in the point spread function (PSF) in the axial direction, indicating the existence of crosstalk. The relative amplitude of this tail with respect to the mainlobe was less than -20 dB. 相似文献
The chlorination of a titaniferous magnetite with low content in Ti and Fe has been studied between 1273 and 2273 K. Most
of the hercynite and ilmenite initially present are decomposed during the gas-solid phase reaction between 1273 and 1823 K.
Considerable ilmenite decomposition and FeCl3evolution already occur at 1273 K, leaving a residue consisting of TiO2, Fe2O3-TiO2 (pseudobrookite), and about 50 pct of each of the Cr and Mg initially present. X-ray diffractograms shown the formation of
Al2TiO5 which contributes to the stabilization of TiO2 up to 1773 K, above which temperature significant decomposition of Al2TiO5 is observed. At the melting point of the titaniferous magnetite sample (around 1823 K), the presence of both solid and liquid
phases result in a considerable decrease in the chlorination rate. In this respect, heating the sample under helium up to
the melting point, so that liquid and solid phases are obtained at equilibrium, yields two structures replacing the magnetite
present just prior to melting. One of these structures is of the spinel Fe2TiO4 type, while the other is a combination of the spinel types MgAl2O4, FeAl2O4, and MgCr2O4. When the sample is chlorinated, a high proportion of the initial Cr (90 pct) and Ti (80 pct) are found in the chlorination
residue at the early stages of fusion, together with 13 pct of the initial Fe. Chlorination of the liquid phase between 1823
and 2273 K shows a steady decrease of Ti and Cr in the chlorination residue, associated with an increase of Fe content. 相似文献
Transport phenomena within PEM fuel cells are investigated and a comprehensive analytical solution is presented. The methodology couples the transport within the fuel cell supply channels and the substrate which is composed of five different layers. The layers are all treated as macroscopically homogeneous porous media with uniform morphological properties such as porosity and permeability. The locally volume-averaged equations are employed to solve for transport through the porous layers. The problem encompasses complex interfacial transport phenomena involving several porous–porous as well as porous–fluid interfaces. Chemical reactions within the catalyst layers are also included. The method of matched asymptotic expansions is employed to solve for the flow field and species concentration distributions. Throughout the analysis, the choice of the gauge parameters involved in the perturbation solutions for velocity and concentration is found to be inherently tied to the physics of the problem and therefore an important physical metric. The analytical solution is found to be in excellent agreement with prior computational simulations. The analytical results are used to investigate several aspects of transport phenomena and their substantial role in PEM fuel cell operation. The solution presented in this work provides the first comprehensive analytical solution representing fuel cell transport phenomena. 相似文献
The behaviours of ten minor coal elements (Al, Ca, Fe, K, Mg, Mn, Na, P, Si and Ti) during coal combustion in the temperature range 400–2000 K, under both oxidising and reducing conditions, have been studied in detail by a thermodynamic equilibrium analysis.
The partitioning of these elements is calculated both in single minor element–coal–chlorine systems and in minor elements co-existing systems. Their vaporisation tendency is found in the order: (Si, Al)<(Fe, Ti)<(Ca, Mn)<(K, Na, P, Mg). Si, Ti, Al and P are present mostly as oxides and K and Na as chlorides, whatever the combustion conditions. Al, Ca, Fe, K, Mn and Na sulphates are dominant at low temperatures under oxidising conditions, whereas under reducing conditions most of them are sulphides and/or chlorides. Moreover, the interactions between these elements affect their major speciation: some species containing two elements among those studied are dominant in the minor elements co-existing systems. The affinities of minor coal elements to sulphur have been studied versus both temperature (400 or 800 K) and sulphur content (0.0062–6.20 wt.% in the coal), in order to find out their influence on the flue gas desulfurization. Two coal samples with different ash contents were considered, and it was found that the ash composition affects greatly the minor elements partitioning. 相似文献