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1.
A new and computationally efficient method is developed for characterizing a spherically focused, ultrasonic transducer (and
its accompanying test system). Procedures for determining the probe's effective radius, effective focal length, and system
efficiency factor are described. Predicted responses that make use of these effective parameters are shown to correspond very
well to measured responses for a number of different transducers. 相似文献
2.
R Dawra A Saluja MM Lerch M Saluja C Logsdon M Steer 《Canadian Metallurgical Quarterly》1993,193(3):814-820
Pancreatic acinar cells possess both high low affinity receptors for cholecystokinin. The cholecystokinin analog caerulein, which exerts a trophic effect on the rat pancreas, acts as an agonist at both types of receptors. In contrast, the synthetic analog CCK-JMV-180, which also acts as an agonist at high affinity receptors, opposes the action of caerulein on the low affinity receptors. We report that infusion of either caerulein or CCK-JMV-180 into rats increases [3H]-thymidine incorporation into pancreatic DNA and causes the pancreatic weight as well as content of DNA, RNA, and protein to increase. CCK-JMV-180 also stimulates in-vitro incorporation of [3H]-thymidine into DNA of cultured rat acini. The finding that both caerulein and CCK-JMV-180 exert the same trophic effect on pancreatic acinar cells indicates that this effect is mediated via high affinity acinar cell cholecystokinin receptors. 相似文献
3.
F. Javier Lerch Deborah J. Ballou Donald E. Harter 《Annals of Software Engineering》1997,3(1):345-366
We describe the use of simulation‐based experiments to assess the computer support needs of automation supervisors in the United States Postal Service (USPS). Because of the high cost of the proposed system, the inability of supervisors to articulate their computer support needs, and the infeasibility of direct experimentation in the actual work environment, we used a simulation to study end‐user decision making, and to experiment with alternative computer support capabilities. In Phase One we investigated differences between expert and novice information search and decision strategies in the existing work environment. In Phase Two, we tested the impact of computer support features on performance. The empirical results of the two experiments showed how to differentially support experts and novices, and the effectiveness of proposed information systems before they were built. The paper concludes by examining the implications of the project for the software requirements engineering community. 相似文献
4.
AU Teuscher M Lerch S Shaw G Pacini P Ferrari P Weidmann 《Canadian Metallurgical Quarterly》1998,16(9):1279-1284
OBJECTIVES: Elevated plasma endothelin (ET)-1 levels have been described in insulin-resistant states such as syndrome X, obesity, non-insulin-dependent diabetes mellitus, and in some studies in essential hypertension. To investigate whether increases in circulating ET-1 to levels observed in insulin-resistant states can modulate insulin levels and/or insulin sensitivity in humans, we assessed these variables during low, non-pressor-dose ET-1 compared with placebo infusion. DESIGN: In a randomized, single blind, crossover design, 10 lean normotensive male subjects received either an intravenous infusion of subpressor doses of ET-1 dissolved in polygeline or a control infusion of polygeline only (placebo). Using dynamic assessment by the minimal model approach with the modified frequent sampling intravenous glucose tolerance test (FSIGT) the following and other parameters were measured: insulin sensitivity; acute insulin response to glucose (AIR(G)) calculated as the average of the three peak values between 2 and 5 min after injection of glucose from which the basal insulin levels were subtracted; the initial area under the curve (AUC(1-19)) from insulin values between time 0 and 19 min and the first-phase insulin secretion (phi1) from insulin kinetics parameters. RESULTS: ET-1 infusion reduced AIR(G) (to 34.85 +/- 4.27 compared with 49.3 +/- 6.9 microU/ml during placebo, P=0.017) and the acute C-peptide response to glucose (to 2.33 +/- 0.41 compared with 3.1 +/- 0.44 ng/ml, P=0.018), decreased plasma insulin levels during the FSIGT compared with placebo (analysis of variance P<0.0001) and decreased the AUC(1-19) (to 2.1 +/- 0.2 compared with 2.9 +/- 0.3 U/l per 20 min, P<0.01) while phi1 tended to be lower. S1 measured during ET-1 infusion was unaltered (11.11 +/- 1.91 x 10(-4) versus 10.88 +/- 2.11 10(-4)/min per mU per l, NS). CONCLUSIONS: These findings demonstrate that an increase in circulating ET-1 to levels observed in insulin-resistant states acutely diminishes the insulin secretory response but does not significantly modify insulin sensitivity. 相似文献
5.
B.‐A. Behrens S. Betancur Escobar H. Niemeier A. Almohallami M. Vucetic I. Nolte K. Lucas C. Stukenborg‐Colsmann M. Lerch A. Bouguecha 《Materialwissenschaft und Werkstofftechnik》2015,46(9):894-910
In recent years, the use of hip prostheses has become a routine procedure. The use of total hip replacement has evolved in recent years to a routine procedure. Despite this experience, it always comes back to complications. Especially the migration or loosening of the acetabular component because of the artificial load adaptive bone remodeling is still a current problem. This is due to the changing mechanical situation after the implantation of the prosthesis. Another problem is the high bone loss during implantation, which complicates a revision of the prosthesis. One solution is the use of patient‐specific prostheses. So far, the use of these prostheses is limited due to the time‐consuming and cost‐intensive production. The overall objective of the presented project in this publication is the development and establishment of an innovative concept for the production of patient‐specific hip prosthesis made of titanium plates by sheet metal forming. The idea of this concept involves the development of a two‐stage process. First of all a standardized hip prosthesis is made by high‐pressure sheet metal forming and then individually in the second step. This publication contains the derivation of the standard prosthesis. For this purpose, a design methodology was generated, based on the so‐called agglomerative clustering. In addition, presents the results of the numerical preliminary design of the first stage of the process and the tool developed concept in the course of this paper. 相似文献
6.
Reinhard Lerch 《e & i Elektrotechnik und Informationstechnik》2002,119(1):a29-a30
ProdukteW-Reihe Gem?ss en 50 124-1
Weidmüller Ein-Bolzen-Klemme 相似文献7.
Frequency security constrained short-term unit commitment 总被引:2,自引:0,他引:2
In island grids and weakly interconnected power systems, a loss of a large proportion of generation will cause the system frequency to fall dramatically. In order to ensure a stable operation with the lowest impact on the system, the disturbed power balance must be equalized within a short specified time by activating the seconds reserve of on-line units or by load shedding or both. This paper presents a frequency security constrained short-term scheduling. The procedure commits and optimizes units, calculates necessary seconds reserve capability, and allocates them among the available on-line units to provide emergent frequency regulation following a loss of generation. By means of the low-pressure pre-heater interruption (LPHI) implemented into thermal power plants, seconds reverse provision is increased. Thus, load shedding caused by insufficient availability of seconds reserve can be avoided. A case study on typical island systems with a large number of different units is demonstrated using the proposed procedure. Results from the study validated robust performance of the proposed procedure that minimizes fuel costs while maintaining frequency security condition. 相似文献
8.
Reinhard Lerch 《e & i Elektrotechnik und Informationstechnik》2002,119(1):a29
ProdukteHeraeus Sensor-Nite
Platinentechnologie auf dem Vormarsch 相似文献9.
Katja Lerch Prof. Dr.‐Ing. Jörg Hinrichs Patrizia Dittmer Dr. Johannes Rauschnabel 《化学,工程师,技术》2013,85(3):323-332
Falling films in wash down process are of major interest for pharmaceutical isolators, which are used for processing of highly potent pharmaceutical products. In this study multiple process parameters were examined with common materials of isolator systems. The importance of material and surface finish in respect of cleanability and complete wetting as well as a combination of process parameters are presented and discussed. For cleaning validation an effect of high interest was discovered: swab sampling areas changed their properties over many repeated cycles and showed decreased cleanability. 相似文献