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21.
A detailed study of the formation of trinitropyridine-1-oxide from dinitroethanol led to the hitherto unknown 2,4,6-trinitropyridine. Thus, nitropyridines become accessible which cannot be obtained by direct nitration. The novel substances were characterized by analytical methods and their spectral data (UV, IR, NMR). First results from the research of their physical, thermical and explosive properties are presented. 相似文献
22.
A Fast Algorithm for Image Component Labeling with Local Operators on Mesh Connected Computers 总被引:1,自引:0,他引:1
A new parallel algorithm for image component labeling with local operators on SIMD mesh connected computers is presented. This algorithm provides a positive answer to the open question of whether there exists an O(n)-time and O(log n)-space local labeling algorithm on SIMD mesh connected computers. The algorithm uses a pipeline mechanism with stack-like data structures to achieve the lower bound of O(n) in time complexity and O(log n) in space complexity. Additionally, the algorithm has very small multiplicative constants in its complexities by using local parallel-shrink and label-propagate operations. 相似文献
23.
24.
Bruce Tonn K.C. Healy Amy Gibson Ashutosh Ashish Preston Cody Drew Beres Sam Lulla Jim Mazur A.J. Ritter 《Energy Policy》2009
This paper presents United States energy portfolios for the year 2030, developed from seven different Perspectives. The Perspectives are characterized by different weights placed on fourteen defining values (e.g., cost, social acceptance). The portfolios were constructed to achieve three primary goals, energy independence, energy security, and greenhouse gas reductions. The portfolios are also evaluated over a comprehensive set of secondary criteria (e.g., economic growth, technical feasibility). It is found that very different portfolios based on very different defining values can achieve the three primary goals. Commonalities among the portfolios include reliance upon cellulosic ethanol, nuclear power, and energy efficiency to meet year 2030 energy demands. It is concluded that the US energy portfolio must be diverse and to achieve national energy goals will require an explicit statement of goals, a strong role for government, and coordinated action across society. 相似文献
25.
Ritter F.E. Van Rooy D. Amant R.St. Simpson K. 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》2006,36(3):592-601
Models of users are a way to understand and improve the usability of computer interfaces. We present here a model in ACT-R cognitive-modeling language that interacts with a publicly available driving simulation as a simple analog for robot interfaces. The model interacts with the unmodified Java interface by incorporating a novel use of bitmap parsing. The model's structure starts to describe the knowledge a human operator of a robot must have. The model also indicates some of the aspects of the task will be difficult for the operator. For example, the model's performance makes quantitative predictions about how robot speed will influence navigation quality, correlating well to human performance. While the model does not cover all aspects of human-robot interaction, it illustrates how providing user models access to an interface through its bitmap can lead to more accurate and more widely applicable model users. 相似文献
26.
We present a method for efficiently calculating the interference of complex-valued two-dimensional wave patterns that is useful during the generation of synthetic holograms. These patterns are represented as a special kind of images (textures), and the interference is calculated in a computer graphics rendering process. This enables us to leverage hardware support for holographic imaging that is implemented in many state-of-the-art computer workstations. Using this approach, we gain a speedup of a factor of 60-90 compared with conventional calculation methods for interfering wave patterns. Our method is evaluated numerically, examples are shown, and the program code is outlined. 相似文献
27.
Intracerebroventricular administration of neuropeptide Y to normal rats induces a syndrome characterised by obesity, hyperinsulinaemia, insulin resistance and over expression of the adipose tissue ob gene. Little is known about the effect of circulating neuropeptide Y on glucose metabolism, insulin secretion and leptin. We therefore aimed to evaluate the effect of an intravenous infusion of neuropeptide Y on glucose disposal, endogenous glucose production, whole body glycolytic flux, and glucose storage as assessed during euglycaemic hyperinsulinaemic clamp. In addition, the insulin-stimulated glucose utilisation index in individual tissues was measured by the 2-deoxy-[1-3H]-glucose technique. The effect of neuropeptide Y on insulin secretion was evaluated by hyperglycaemic clamp. Infusion did not induce any change in endogenous glucose production during basal conditions or at the end of the clamp. Glucose disposal was significantly increased in the rats given neuropeptide Y compared with controls (27.8 +/- 1.3 vs 24.3 +/- 1.6 mg x min(-1) x kg(-1); p < 0.05) as was the glycolytic flux (18.9 +/- 1.6 vs 14.4 +/- 0.8 mg x min(-1) x kg(-1); p < 0.05), while glucose storage was comparable in the two groups. In skeletal muscle, the glucose utilisation index was increased significantly in rats given neuropeptide Y. The glucose utilisation index in subcutaneous and epididimal adipose tissue was not significantly different between the two groups. Plasma leptin was significantly increased by hyperinsulinaemia, but was not affected by neuropeptide Y infusion. Both the early and late phase of the insulin response to hyperglycaemia were significantly reduced by neuropeptide Y. In conclusion neuropeptide Y infusion may increase insulin-induced glucose disposal in normal rats, accelerating its utilisation through the glycolytic pathway. Neuropeptide Y reduces both phases of the insulin response to hyperglycaemia. 相似文献
28.
During the last 10 years, there has been a movement to expand the definition of prenatal care to encompass preconceptional counseling. Major organizations throughout the world have endorsed preconceptional counseling as an integral component of care for all women contemplating pregnancy. This article will assist health care providers who interact with women of reproductive age to understand the potential benefits and limitations of preconceptional counseling and to develop an approach to that service relating to nutrition, infections, and metabolic diseases as they impact on reproductive outcome. Although there are many potential benefits of the preconception health care model, barriers to its implementation remain. 相似文献
29.
E. Talman P. E. J. Verwiel F. J. Ritter C. J. Persoons 《Israel journal of chemistry》1978,17(3):227-235
Two sex pheromones, periplanone A and periplanone B were isolated from the American cockroach Periplaneta americana. The technique is described for collecting periplanone B from the alimentary tracts of virgin females. Periplanone A was extracted from the excreta of the insects. Mass spectral analysis of the pheromones and related compounds were performed and the results are reported here. Evidence is presented suggesting that periplanone A is in fact a degradation product of periplanone B. A reaction scheme is considered for the pathway: periplanone B → periplanone A → (stable, but inactive) PA 22–VII. 相似文献
30.
The open loop dynamic response of a laboratory scale double effect evaporator has been adequately described by a simple mathematical model based on the unsteady state material and energy balances associated with the various elements of the system. Excellent agreement has been achieved between the experimentally determined response of the evaporator to large disturbances in steam rate and feed rate and the predicted response based on the digital computer solution of the non linear model. 相似文献