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排序方式: 共有322条查询结果,搜索用时 15 毫秒
31.
Hong-Lei Wang Cheng-Hua Zhao Gabor Szöcs Satya Prabhakar Chinta Stefan Schulz Christer Löfstedt 《Journal of chemical ecology》2013,39(6):790-796
The trienoic and tetraenoic polyenes, (3Z,6Z,9Z)-3,6,9-nonadecatriene, (3Z,6Z,9Z)-3,6,9-henicosatriene, and (3Z,6Z,9Z)-1,3,6,9-henicosatetraene were found in the abdominal cuticle and pheromone gland of the winter moth Operophtera brumata L. (Lepidoptera: Geometridae), in addition to the previously identified single component sex pheromone (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene. The pheromone biosynthesis activating neuropeptide (PBAN) is involved in the regulation of polyene transport from abdominal cuticle to the pheromone gland. In vivo deuterium labeling experiments showed that (11Z,14Z,17Z)-11,14,17-icosatrienoic acid, the malonate elongation product of linolenic acid, (9Z,12Z,15Z)-9,12,15-octadecatrienoic acid, is used to produce (3Z,6Z,9Z)-3,6,9-nonadecatriene and (3Z,6Z,9Z)-1,3,6,9-nonadecatetraene. 相似文献
32.
Christer Svensson J. Jacob Wikner 《Analog Integrated Circuits and Signal Processing》2010,65(2):171-184
A systematic approach to the power consumption of analog circuits is presented. The power consumption is related to basic
circuit requirements, as dynamic range, bandwidth, noise figure and sampling speed and is considering basic device and device
scaling behavior. Several kinds of circuits are treated, as samplers, amplifiers, filters and oscillators. The objective is
to derive lower bounds to power consumption in analog circuits, to be used as design targets when designing power-constrained
analog systems. 相似文献
33.
Christer Richt P 《数控机床市场》2009,(3)
要想以相对较高的生产效率来加工耐热超级合金,必须充分仔细地准备相应的加工策略。由于加工此类材料的零件时至少50%以上的工序为车削,因此其基本原则应立足于采用合适的切削刃切入方法。 相似文献
34.
The purpose of this paper is to improve the tools available for analyzing and evaluating land-use and transport policies in a regional planning context. A normative residential location submodel is combined with a predictive submodel for the location of employment. The demand side of the residential location submodel is formulated as a nested multinomial logit model of the joint choice of residential location and transportation mode. The cost of commuting is assumed to be a major determinant of locational choice. The employment location submodel is based on the assumption that accessibility to the labor force is the strategic location factor. Two versions of the submodels are proposed corresponding to a post- and pre-distribution modal split in the familiar four-step transport model. Policy tests of a newly proposed, large-scale traffic investment program in the Stockholm region are reported.An earlier version of this paper was presented at the 30th European Congress, Istanbul, August 1990. 相似文献
35.
Christer Jansson Per Ingelhag Christer Svensson Robert Forchheimer 《Analog Integrated Circuits and Signal Processing》1993,4(1):37-49
We have constructed an addressable 256 × 256 photodiode sensor array together with an 8-bit ADC (analog-to-digital converter) on the same chip. Such a digital camera is easy to connect to a computer where also the flexibility of the computer can be used to control the camera output. The sensor has been constructed in two versions. The first version was implemented with a 256-column parallel-bit-slice image processor on the same die in a commercial project and the second as a separate addressable digital image sensor. The sensor was functionally fabricated using 1.6 µm design rules in a 1.2 µm CMOS process where it required a total area of 96 mm2. 相似文献
36.
Kaupo Kukli Mikko Ritala Teet Uustare Jaan Aarik Katarina Forsgren Timo Sajavaara Markku Leskel Anders Hrsta 《Thin solid films》2002,410(1-2):53-60
ZrO2 films of thicknesses varied in the range of 3–30 nm were atomic layer deposited from ZrI4 and H2O–H2O2 on p-Si(100) substrates. The effects of film thickness and deposition temperature on the structure and dielectric properties of ZrO2 were investigated. At 272 and 325 °C, the growth of ZrO2 started with the formation of the cubic polymorph and continued with the formation of the tetragonal polymorph. The ratio between the lattice parameters increased with the film thickness and growth temperature. The effective permittivity, determined from the accumulation capacitance of Hg/ZrO2/Si capacitors, increased with the film thickness, reaching 15–17 in 25-nm-thick films. The permittivity decreased with the increasing growth temperature. The hysteresis of the capacitance–voltage curves was the narrowest for the films deposited at 325 °C, and increased towards both lower and higher deposition temperatures. 相似文献
37.
A general kinetic model was developed to simulate the grafting of monomers such as unsaturated carboxylic acids and silanes to ethylene polymers. The polymers considered were ethylene-co-vinyl acetate (EVA), ethylene-co-butyl acrylate (EBA), and low-density polyethylene (LDPE). Grafting was assumed to proceed by a free-radical mechanism involving chain transfer. Organic peroxides having a strong tendency for hydrogen abstraction were selected as the source of primary radicals. The model simulated the grafting reaction as taking place in a single screw extruder. The residence time distribution in the extruder was experimentally determined by tracer analysis, according to which the extruder was a plug-flow reactor connected to two mixed reactors in parallel. The model is able to predict the extent of grafting in terms of predefined parameters. Comparison of model predictions with available experimental data showed slight deviations, the possible causes of which are discussed. However, the kinetic behavior expected on the basis of the input parameters was observed, and, as such, the model allowed study of the effect of process variables on grafting kinetics and provided insight into the reaction mechanism. 相似文献
38.
Thorbjörn Andersson Gunnar Forsgren & Tim Nielsen 《International Journal of Food Science & Technology》2005,40(9):993-1004
The effects of selected aldehydes, ketones and carboxylic acids on the development of off‐flavours in water were studied. Combinations of hexanal, octanal, 2‐octanone, 5‐nonanone, hexanoic acid and nonanoic acid were rated by the off‐flavour intensities they created in water at concentrations just at or below the threshold value of each analyte. Two different sensory panels evaluated the off‐flavours induced by different combinations of the analytes. The observations of the two panels agreed well. From these studies, it could be concluded that aldehydes play an important role in the development of off‐flavours intensities in water. There were synergistic effects between aldehydes and ketones, as well as between aldehydes and carboxylic acids. Small amounts of aldehydes and carboxylic acids – well below their respective threshold values – caused an increase in the off‐flavour intensity. No synergism between ketones and carboxylic acids could be observed. 相似文献
39.
Pyrolysis enables to recover metals and organic feedstock from waste conglomerates such as: automotive shredder residue (ASR). ASR as well as its pyrolysis solid products, is a morphologically and chemically varied mixture, containing mineral materials, including hazardous heavy metals. The aim of the work is to generate fundamental knowledge on the conversion of the organic residues of the solid products after ASR's microwave pyrolysis, treated at various temperatures and with two different types of gasifying agent: pure steam or 3% (v/v) of oxygen. The research is conducted using a lab-scale, plug-flow gasifier, with an integrated scale for analysing mass loss changes over time of experiment, serving as macro TG at 950, 850 and 760 °C. The reaction rate of char decomposition was investigated, based on carbon conversion during gasification and pyrolysis stage. It was found in both fractions that char conversion rate decreases with the rise of external gas temperature, regardless of the gasifying agent. No significant differences between the reaction rates undergoing with steam and oxygen for char decomposition has been observed. This abnormal char behaviour might have been caused by the inhibiting effects of ash, especially alkali metals on char activity or due to deformation of char structure during microwave heating. 相似文献
40.