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排序方式: 共有681条查询结果,搜索用时 31 毫秒
61.
AS Piatek S Tyagi AC Pol A Telenti LP Miller FR Kramer D Alland 《Canadian Metallurgical Quarterly》1998,16(4):359-363
Strictureplasty for treatment of symptomatic intestinal strictures secondary to Crohn's disease is being performed with increasing frequency. To determine the overall clinical results after strictureplasty for Crohn's disease, all patients undergoing this procedure were prospectively studied. Between 6/1/89 and 2/1/97, 57 Crohn's disease patients underwent 60 operations utilizing strictureplasties. A total of 109 strictureplasties were performed (90 Heineke-Mikulicz, 6 Finney, and 13 side-to-side isoperistaltic). The 30-day perioperative morbidity was 12%, with complications being less common for patients undergoing elective versus unscheduled operations (p < 0.002). Recurrence of Crohn's disease requiring operation was seen in seven patients after a mean follow-up of 38 months. The estimated cumulative recurrence rate after 2 years was 15 +/- 6% (+/- standard error) and 22 +/- 10% at 5 years. A recurrence developed at the site of the previous strictureplasty in only five cases. Strictureplasty is a safe, effective means of providing long-term surgical palliation to selected patients with Crohn's disease. Perioperative complication rates are comparable to those seen with standard surgical treatment, and recurrences are not excessive. 相似文献
62.
A 90-nm logic technology featuring strained-silicon 总被引:10,自引:0,他引:10
Thompson S.E. Armstrong M. Auth C. Alavi M. Buehler M. Chau R. Cea S. Ghani T. Glass G. Hoffman T. Jan C.-H. Kenyon C. Klaus J. Kuhn K. Zhiyong Ma Mcintyre B. Mistry K. Murthy A. Obradovic B. Nagisetty R. Phi Nguyen Sivakumar S. Shaheed R. Shifren L. Tufts B. Tyagi S. Bohr M. El-Mansy Y. 《Electron Devices, IEEE Transactions on》2004,51(11):1790-1797
A leading-edge 90-nm technology with 1.2-nm physical gate oxide, 45-nm gate length, strained silicon, NiSi, seven layers of Cu interconnects, and low-/spl kappa/ CDO for high-performance dense logic is presented. Strained silicon is used to increase saturated n-type and p-type metal-oxide-semiconductor field-effect transistors (MOSFETs) drive currents by 10% and 25%, respectively. Using selective epitaxial Si/sub 1-x/Ge/sub x/ in the source and drain regions, longitudinal uniaxial compressive stress is introduced into the p-type MOSEFT to increase hole mobility by >50%. A tensile silicon nitride-capping layer is used to introduce tensile strain into the n-type MOSFET and enhance electron mobility by 20%. Unlike all past strained-Si work, the hole mobility enhancement in this paper is present at large vertical electric fields in nanoscale transistors making this strain technique useful for advanced logic technologies. Furthermore, using piezoresistance coefficients it is shown that significantly less strain (/spl sim/5 /spl times/) is needed for a given PMOS mobility enhancement when applied via longitudinal uniaxial compression versus in-plane biaxial tension using the conventional Si/sub 1-x/Ge/sub x/ substrate approach. 相似文献
63.
M. Kamruddin P.K. Ajikumar R. Nithya G. Mangamma A.K. Tyagi Baldev Raj 《Powder Technology》2006,161(2):145-149
Nanocrystalline ceria has been synthesized by a non-hydrolytic method using organic solvent and precipitant. The effect of the source compound on final nanocrystalline powder was investigated. The cerium nitrate hexahydrate subjected to different vacuum/thermal treatments to get cerium source compound having different extent of water of crystallization. The nanoceria, synthesized from these compounds was characterized by TGA-MS, XRD, HR-TEM and AFM. 相似文献
64.
Arumbackam V Elangovan Asit B Mandal Pramod K Tyagi Praveen K Tyagi Saroj Toppo Tripurari S Johri 《Journal of the science of food and agriculture》2004,84(15):2028-2034
The present study was conducted to evaluate the effect of feed‐grade enzyme supplementation in diets with varying levels of energy on the performance of growing and laying Japanese quails. Day‐old Japanese quails, 504 in number, were subjected to six dietary treatments with six replicates at each treatment. Each replicate had 14 chicks. The dietary treatments consisted of three energy levels ie 12.15 MJ (2900 kcal), 11.30 MJ (2700 kcal) and 10.48 MJ (2500 kcal) ME kg?1 diet and two enzyme levels (0 and 0.5 g kg?1 diet). A metabolism trial was conducted at the fourth week of age. At the end of week 5, 10 quails (five of each sex) per treatment were sacrificed for carcass characteristics and 20 female quails from each of the six dietary groups were housed in individual laying cages and fed respective layer diet to study the laying performance and egg quality up to 20 weeks of age. Body weight gains of quails fed 12.15 MJ or 11.30 MJ ME kg?1 diets were significantly higher (p < 0.01) than those fed diets with 10.46 MJ ME kg?1 diet. Feed intake was significantly lower (p < 0.01) in birds that received diet with 12.15 MJ ME kg?1 than in birds that diets containing either 11.30 or 10.46 MJ ME kg?1 diet. Feed conversion ratio (p < 0.01) was best at 12.15, followed by 11.30 and 10.46 MJ ME kg?1 diet. Enzyme supplementation did not improve the growth performance, feed intake or feed conversion efficiency of quails. Enzyme addition also did not influence nitrogen retention or energy or dry matter metabolizability. The carcass characteristics did not differ because of energy or enzyme supplementation. Feed intake increased significantly (p < 0.01) as the dietary energy level decreased. The egg production and quality characteristics remained almost similar in all the dietary treatments. It was concluded that the optimum dietary energy level for quail was 12.15 MJ (2900 kcal) ME kg?1 during the growing phase and 11.30 MJ (2700 kcal) ME kg?1 during the laying phase. Addition of feed enzymes to conventional diets containing varying levels of maize, soyabean meal, fish meal and deoiled rice bran was not beneficial to improve growth, carcass traits, egg production performance or nutrient utilization. Copyright © 2004 Society of Chemical Industry 相似文献
65.
Amorphous ferromagnetic alloys are a promising class of materials that have been successfully used as magnetostrictive elements in fiber optic magnetic sensors. We have used ferromagnetic resonance (FMR) at about 9.5 GHz to characterize highly magnetostrictive film coatings of the amorphous ferromagnetic alloy Fe81B13.5Si3.5C2.R.f. sputtering was used to prepare films 0.1–0.6 μm thick on glass substrates and cladded single-mode optical fibers of diameter approximately 80 μm. Because of its inherent sensitivity, the FMR technique is shown to be an excellent non-destructive probe for investigating microscopic as well as macroscopic structural inhomogeneities that may arise from the fabrication process itself, subsequent handling or thermal aging of the coatings. An added advantage of the FMR technique is that it also allows a simultaneous measurement of such material parameters as the saturation magnetostriction coefficient, the saturation magnetization, the g factor and the uniaxial magnetic anisotropy energy. The effect of thermal annealing on some of these properties is also reported. 相似文献
66.
High voltage electron microscope (hvem) has been extensively used to produce radiation damage and to study the characteristics of defects so produced in crystalline
solids. To understand the defect production in metallic glasses and to evaluate the influence of such defects on physical
properties like crystallisation temperature etc., high voltage microscopy and subsequentin situ heating and observation has been extremely useful technique. This paper gives a qualitative overview of such work performed
in metallic glasses. In particular results obtained on a nickel based metallic glass using ahvem and an electron accelerator are presented. The advantages and limitations ofhvem irradiation are highlighted. 相似文献
67.
This paper presents the analysis of a two unit cold standby system with random arrival time of a server. The failure and repair times of each unit are assumed to be correlated and their joint density is taken as bivariate exponential. Using the regenerative point technique, various reliability characteristics of the system have been obtained. The behaviour of MTSF and steady state availability have also been studied through graphs. 相似文献
68.
K. P. Yadava B. S. Tyagi V. N. Singh 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1991,51(1):47-60
The removal of Pb(II) from aqueous solution by adsorption on china clay and wollastonite is an attractive process. The amount of Pb(II) removed by adsorption is highly dependent on the temperature of the adsorbate solution and favours low temperature. The equilibrium times were noted, i.e. 90 min for china clay and 120 min for wollastonite. The various rate parameters of the adsorption process have been determined at different temperatures. The activation energies were determined and found to be ?5.345 kJ mol?1 and ?8.730 kJ mol?1 for Pb(II)-china clay and Pb(II)-wollastonite systems, respectively. The adsorption isotherm was measured experimentally at various temperatures. The negative values of enthalpy change (ΔH = ?77.95 kJ mol?1 and ?16.40 kJ mol?1 for china clay and wollastonite, respectively) indicate the exothermic nature of the adsorption processes for both systems. The isosteric heats of the adsorption process have been determined at various surface coverages of the adsorbents used. The various thermodynamic parameters have been calculated to elucidate the mechanism involved in the adsorption process. 相似文献
69.
70.
OBJECTIVE: To study the trends of paralytic poliomyelitis in pre Pulse Polio Immunization period. SETTING: Hospital based sentinel surveillance. METHODS: Analysis of 6704 line-listed poliomyelitis cases from January 1989 to December 1994 attending the Department of Physical Medicine and Rehabilitation. RESULTS: 85% of all cases reported in Delhi were from this center. A decline in alternate year peaks was observed from 1621 cases in 1990 to 1062 cases in 1994. There was an increase in proportion of cases with poliomyelitis in fully vaccinated children from 14% to 22.9%. Polio type I virus was the commonest isolated virus in all the years except 1993, when type II was isolated in 38.7% of cases. CONCLUSION: Despite improvement in immunization coverage, the study reveals that a large number of children (67.2%) who suffer from poliomyelitis are unvaccinated. This stresses need to intensify and sustain high level of immunization coverage with effective vaccine. 相似文献