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排序方式: 共有109条查询结果,搜索用时 15 毫秒
1.
Taking into consideration a study published 10 years ago on sexual disturbances of students at the University of S?o Paulo, the importance of the subject is discussed, along with the creation in 1993 of the Sexuality Project at the university hospital of the University of S?o Paulo School of Medicine. In its first year, this multidisciplinary project attended 140 patients with sexual dysfunctions (associated or not to other clinical manifestations); the majority were younger than 60 years-old, and 80 percent were male. 相似文献
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3.
Houssein Essam H. Hosney Mosa E. Mohamed Waleed M. Ali Abdelmgeid A. Younis Eman M. G. 《Neural computing & applications》2023,35(7):5251-5275
Neural Computing and Applications - Feature selection (FS) is one of the basic data preprocessing steps in data mining and machine learning. It is used to reduce feature size and increase model... 相似文献
4.
The existing measurements of global solar radiation and sunshine duration for Yemen are examined. The errors of estimating solar radiation from sunshine hour measurements using Angstrom's relation are evaluated. As a simple predictor for global radiation, an average Ansgtrom relations in the form
for all stations is evaluated. Other Angstrom correlation relations are also proposed by classifying the stations under into four groups. The estimated results are compared and seem to be satisfactory in the latter case. 相似文献
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5.
Olivier Noel Houssein Awada Gilles Castelein Maurice Brogly Jacques Schultz 《The Journal of Adhesion》2006,82(7):649-669
The atomic force microscope (AFM) can be used to perform surface force measurements in the quasi-static mode (cantilever is not oscillating) to investigate nanoscale surface properties. Nevertheless, there is still a lack of literature proposing a complete systematic and rigorous experimental procedure that enables one to obtain reproducible and significant quantitative data. This article focuses on the fundamental experimental difficulties arising when making force curve measurements with the AFM in air. On the basis of this AFM calibration procedure, quantitative assessment values were used to determine, in situ, SAM (or Self Assembled Monolayer)-tip thermodynamic work of adhesion at a local scale, which have been found to be in good agreement with quoted values. Finally, determination of surface energies of functionalised silicon wafers (as received, CH3, OH functionalised silicon wafers) with the AFM (at a local scale) is also proposed and compared with the values obtained by wettability (at a macroscopic scale). In particular, the effect of the capillary forces is discussed. 相似文献
6.
Abdulrahman Al-Ahmari Mohammad Ashfaq Abdullah Alfaify Basem Abdo Abdulrahman Alomar Abdelnaser Dawud 《Journal of Mechanical Science and Technology》2016,30(1):345-352
Electron beam melting (EBM) has been found to be a promising technology for producing complex shaped parts from gamma titanium aluminide alloys (γ-TiAl). The parts produced by this process are projected to have dimensions very close to the desired final shapes. However, the surface roughness of the parts produced by EBM is excessively rough. In many applications, it is necessary to improve the quality of manufactured parts using a convenient post process. This paper determines process parameters of end milling when it is used as a post process for the parts produced by EBM. Design of experiments has been used to study the effect of the selected input parameters of end milling (spindle speed, feed rate, depth of cut and coolant type) on the surface roughness of γ-TiAl parts. Response surface methodology is used to develop a predictive model for surface roughness. Effects of the selected milling process are investigated. This paper also optimizes the selected process parameters to minimize the value of the obtained surface roughness. 相似文献
7.
Abdo AbdelMonem Shaalan M. I. Ramadan 《Journal of Infrared, Millimeter and Terahertz Waves》2010,31(8):958-968
This paper presents two design compact hexagonal monopole antennas for ultra-wideband applications. The two antennas are fed
by a single microstrip line . The Zeland IE3D version 12 is employed for analysis at the frequency band of 4 to 14 GHz which
has approved as a commercial UWB band. The experimental and simulation results exhibit good agreement together for antenna
1. The proposed antenna1 is able to achieve an impedance bandwidth about 111%. The proposed antenna2 is able to achieve an
impedance bandwidth about (31.58%) for lower frequency and (62.54%) for upper frequency bandwidth. A simulated frequency notched
band ranging from 6.05 GHz to 7.33 GHz and a measured frequency notched band ranging from 6.22 GHz to 8.99 GHz are achieved
and gives one narrow band of axial ratio (1.43%). The proposed antennas can be used in wireless ultra-wideband (UWB) communications. 相似文献
8.
Stabilization loop of a two axes gimbal system using self-tuning PID type fuzzy controller 总被引:3,自引:0,他引:3
The application of inertial stabilization system is to stabilize the sensor's line of sight toward a target by isolating the sensor from the disturbances induced by the operating environment. The aim of this paper is to present two axes gimbal system. The gimbals torque relationships are derived using Lagrange equation considering the base angular motion and dynamic mass unbalance. The stabilization loops are constructed with cross coupling unit utilizing proposed fuzzy PID type controller. The overall control system is simulated and validated using MATLAB. Then, the performance of proposed controller is evaluated comparing with conventional PI controller in terms of transient response analysis and quantitative study of error analysis. The simulation results obtained in different conditions prove the efficiency of the proposed fuzzy controller which offers a better response than the classical one, and improves further the transient and steady-state performance. 相似文献
9.
JE Monteiro da Cunha MC Machado P Herman T Bacchella EE Abdo S Penteado J Jukemura A Montagnini MA Machado HW Pinotti 《Canadian Metallurgical Quarterly》1998,45(23):1452-1456
BACKGROUND/AIMS: Cicatricial biliary strictures are usually associated with high morbidity and mortality rates, frequently related to technical difficulties of their surgical repair, mainly in hilar lesions. Interference with bile duct blood supply during surgical attempts for correction is a major factor for unsuccessful results. The aim of this study is to evaluate, after an extended follow-up period, the results obtained with a modified technique for surgical correction of cicatricial biliary strictures. METHODOLOGY: The medical records of 57 patients surgically treated for cicatricial biliary strictures between January 1984 and July 1995 were reviewed and the immediate and long term results retrospectively analyzed. Patients consisted of 46 females and 11 males. The average age was 43 years. The etiology of the biliary lesion was: cholecystectomy alone (23); cholecystectomy with duct exploration (8); T tube CBD drainage (6); Biliary-enteric anastomosis stricture (16); choledochoplasty (2) and trauma (2). In 28 cases (49.1%) the stricture was located in the upper third of the bile duct, in 28 (49.1%) in the middle third and in one case (1.7%) it was low. All patients were submitted to longitudinal Roux-en-Y hepaticojejunostomy with mucosa apposition after dissection of the anterior aspect of the biliary tract. No transanastomotic stents were used. RESULTS: Ten patients (17.5%) presented 11 postoperative complications: biliary fistula (4), duodenal fistula (1), wound infection (5), and acute pancreatitis (1). Average hospital stay was 11 days and there were no postoperative mortalities. The follow-up study was possible in 54 patients and ranged from one to ten years, with an average of 2.9 years. Four patients of 28 (14%) with hilar lesions developed stricture recurrence and cholangitis episodes, whereas no patients bearing lesions below the biliary junction had such complications. CONCLUSION: Roux-en-Y hepaticojejunostomy with mucosa apposition without transanastomotic stent performed after minimal dissection of the biliary duct, thus avoiding major interference with the bile duct blood supply, is a safe and efficient method for the surgical repair of cicatricial biliary strictures. Using this technique excellent results can be obtained in the lesions below the biliary junction and acceptable results may be achieved in patients with hilar lesions. 相似文献
10.
Tarek O. Al Kasabi Said I. Abdel-Khalik Terry E. Dix Randy Hagenson Abdo A. Husseiny Gary P. Mclagan 《Desalination》1981
A completely solar-powered greenhouse complex has been designed for climate controlled food production in hot, humid environments. The concept uses passive design features to provide irrigation water from saline water sources. This paper discusses the overall system concept and the solar still subsystem which has been designed to provide a continuous fresh water supply. While incorporating many innovative features, the use of proven technologies and passive design results in a system that should compete economically with current, more traditional designs. 相似文献