全文获取类型
收费全文 | 67篇 |
免费 | 1篇 |
专业分类
化学工业 | 11篇 |
机械仪表 | 4篇 |
能源动力 | 10篇 |
轻工业 | 5篇 |
无线电 | 5篇 |
一般工业技术 | 13篇 |
冶金工业 | 5篇 |
自动化技术 | 15篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 9篇 |
2012年 | 3篇 |
2011年 | 9篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 5篇 |
2007年 | 4篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 4篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1991年 | 2篇 |
1989年 | 1篇 |
排序方式: 共有68条查询结果,搜索用时 15 毫秒
11.
Fischer Peter; Greitemeyer Tobias; Kastenmüller Andreas; Vogrincic Claudia; Sauer Anne 《Canadian Metallurgical Quarterly》2011,137(3):367
In recent years, there has been a surge in the quantity of media content that glorifies risk-taking behavior, such as risky driving, extreme sports, or binge drinking. The authors conducted a meta-analysis involving more than 80,000 participants and 105 independent effect sizes to examine whether exposure to such media depictions increased their recipients' risk-taking inclinations. A positive connection was found for overall, combined risk taking (g = .41); as well as its underlying dimensions: risk-taking behaviors (g = .41), risk-positive cognitions and attitudes (g = .35), and risk-positive emotions (g = .56). This effect was observed across varying research methods (experimental, correlational, longitudinal); types of media (video games, movies, advertising, TV, music); and differing risk-related outcome measures (e.g., smoking, drinking, risky driving, sexual behavior). Multiple moderator analyses revealed 2 theoretically new boundary conditions for sociocognitive models. First, the effect was stronger for active (i.e., video games) than for passive (e.g., film, music) exposure to risk-glorifying media content. Second, the effect was stronger when there was a high degree of contextual fit between the media content and type of risk-taking measure. The theoretical, practical, and societal implications of the present research synthesis are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
12.
Lean premixed combustion,which allows for reducing the production of thermal NOx,is prone to
combustion instabilities.There is an extensive research to develop a reduced physical model,which
allows-without time-consuming measurements-to calculate the resonance characteristics of a
combustion system consisting of Helmholtz resonator type components (burner plenum,combustion
chamber).For the formulation of this model numerical investigations by means of compressible Large
Eddy Simulation (LES) were carried out.In these investigations the flow in the combustion chamber is
isotherm,non-reacting and excited with a sinusoidal mass flow rate.Firstly a combustion chamber as a
single resonator subsequently a coupled system of a burner plenum and a combustion chamber were
investigated.In this paper the results of additional investigations of the single resonator are
presented.The flow in the combustion chamber was investigated without excitation at the inlet.It
was detected,that the mass flow rate at the outlet cross section is pulsating once the flow in the
chamber is turbulent.The fast Fourier transform of the signal showed that the dominant mode is at
the resonance frequency of the combustion chamber.This result sheds light on a very important
source of self-excited combustion instabilities.Furthermore the LES can provide not only the damping
ratio for the analytical model but the eigenfrequency of the resonator also. 相似文献
combustion instabilities.There is an extensive research to develop a reduced physical model,which
allows-without time-consuming measurements-to calculate the resonance characteristics of a
combustion system consisting of Helmholtz resonator type components (burner plenum,combustion
chamber).For the formulation of this model numerical investigations by means of compressible Large
Eddy Simulation (LES) were carried out.In these investigations the flow in the combustion chamber is
isotherm,non-reacting and excited with a sinusoidal mass flow rate.Firstly a combustion chamber as a
single resonator subsequently a coupled system of a burner plenum and a combustion chamber were
investigated.In this paper the results of additional investigations of the single resonator are
presented.The flow in the combustion chamber was investigated without excitation at the inlet.It
was detected,that the mass flow rate at the outlet cross section is pulsating once the flow in the
chamber is turbulent.The fast Fourier transform of the signal showed that the dominant mode is at
the resonance frequency of the combustion chamber.This result sheds light on a very important
source of self-excited combustion instabilities.Furthermore the LES can provide not only the damping
ratio for the analytical model but the eigenfrequency of the resonator also. 相似文献
13.
Gabi Steinbach Cristian Crisan Siu Lung Ng Brian K. Hammer Peter J. Yunker 《Journal of the Royal Society Interface》2020,17(173)
Bacterial communities are governed by a wide variety of social interactions, some of which are antagonistic with potential significance for bacterial warfare. Several antagonistic mechanisms, such as killing via the type VI secretion system (T6SS), require killer cells to directly contact target cells. The T6SS is hypothesized to be a highly potent weapon, capable of facilitating the invasion and defence of bacterial populations. However, we find that the efficacy of contact killing is severely limited by the material consequences of cell death. Through experiments with Vibrio cholerae strains that kill via the T6SS, we show that dead cell debris quickly accumulates at the interface that forms between competing strains, preventing physical contact and thus preventing killing. While previous experiments have shown that T6SS killing can reduce a population of target cells by as much as 106-fold, we find that, as a result of the formation of dead cell debris barriers, the impact of contact killing depends sensitively on the initial concentration of killer cells. Killer cells are incapable of invading or eliminating competitors on a community level. Instead, bacterial warfare itself can facilitate coexistence between nominally antagonistic strains. While a variety of defensive strategies against microbial warfare exist, the material consequences of cell death provide target cells with their first line of defence. 相似文献
14.
We investigate several evolutionary computation approaches as a mechanism to “program” networks of excitable chemical droplets. For this kind of systems, we assigned a specific task and concentrated on the characteristics of signals representing symbols. Given a Boolean function as target functionality, 2D networks composed of 10 × 10 droplets were considered in our simulations. Three different set-ups were tested: Evolving network structures with fixed on/off rate coding signals, co-evolution of networks and signals, and network evolution with fixed but pre-evolved signals. Evolutionary computation served in this work not only for designing droplet networks and input signals but also to estimate the quality of a symbol representation: we assume that a signal leading to faster evolution of a successful network for a given task is better suited for the droplet computing infrastructure. Results show that complicated functions like XOR can evolve using only rate coding and simple droplet types, while other functions involving negations like the NAND or the XNOR function evolved slower using rate coding. Furthermore we discovered symbol representations that performed better than the straight forward on/off rate coding signals for the XNOR and AND Boolean functions. We conclude that our approach is suitable for the exploration of signal encoding in networks of excitable droplets. 相似文献
15.
16.
Rainer Engelke Gisela Ahrens Norbert Arndt-Staufenbiehl Stefan Kopetz Karin Wiesauer Bernd Löchel Henning Schröder Johann Kastner Andreas Neyer David Stifter Gabi Grützner 《Microsystem Technologies》2007,13(3-4):319-325
LIGA is the basic idea of promising developments for the manufacturing of microelectromechanical system parts containing high
aspect ratio microstructures. Aim of the work is a brief discussion of the starting-points for inline process inspection within
a direct LIGA technology using deep X-ray lithography for the production of micromechanical gear wheels with critical dimensions
of ∼35 μm width at ∼1 mm height as well as to show methodic and technical measuring possibilities. Firstly, results of the
determination of residual solvent content distribution within ultra-thick SU-8 films are shown obtained from refracted near
field optical measurements. Furthermore, the capability of X-ray computer tomographic imaging is discussed and measurements
for the determination of the three-dimensional shape of high aspect ratio microstructures are practically demonstrated with
microscopic and interferometric optical methods. Finally, first results demonstrate the potential of the optical coherence
tomography for several further important measurement tasks, among others, e.g. for the imaging of the distribution of mechanical
stress at the resist–substrate interface. The results show that much information which is essential in the LIGA process can
be achieved with recently available measurement methods. However, further development of non-destructive measurement techniques
would be desirable for an effective inline process control of mass production of micromechanical parts.
This work is a summary of the poster “Residual Solvent Content Distribution in Ultra-Thick SU-8 Films and Its Influence on
the Imaging Quality” and of the presentation “Possibilities of Inline Process Inspection of High Aspect Ratio LIGA Micro Structures”
to the High Aspect Ratio Micro Structure Technology workshop HARMST 2005 held in Gyeongju (Republic of Korea), June 10–13,
2005. 相似文献
17.
Gross A Besov A Reck DD Sorek S Ben-Dor G Britan A Palchikov E 《Environmental science & technology》2003,37(19):4481-4486
A theory developed suggested that significant displacement of solute in saturated porous media results from the propagation of compression waves. Four independent one-dimensional experimental setups and a variety of laboratory methods were used to confirm the predictions of the theory, specifically aimed at developing a novel method of inducing compression waves for use in remediation of contaminated aquifers. Compaction and shock waves were emitted through granular porous media saturated with saline water. The changes in solute concentration at observation points along the propagating wave were used to verify the validity of theory. The first setup was designed mainly to provide a qualitative assessment (i.e., changes in pressure due to the propagating wave were not recorded). In situ quantitative measurements of the pressure and electrical conductivity profiles along a sand column were done with the second and third experimental setups, respectively, to short and long shock waves. In the fourth setup, solute displacement was visualized by X-ray absorption. The findings were consistent with the theory in all experimental setups. 相似文献
18.
The objective of the current study is to develop an automatic tool to identify microbiological data types using computer-vision and statistical modeling techniques. Bacteriophage (phage) typing methods are used to identify and extract representative profiles of bacterial types out of species such as the Staphylococcus aureus. Current systems rely on the subjective reading of profiles by a human expert. This process is time-consuming and prone to errors, especially as technology is enabling the increase in the number of phages used for typing. The statistical methodology presented in this work, provides for an automated, objective and robust analysis of visual data, along with the ability to cope with increasing data volumes. 相似文献
19.
Kapoula Zo?; Adenis Marie-Sarah; Lê Thanh-Thuan; Yang Qing; Lipede Gabi 《Canadian Metallurgical Quarterly》2011,5(2):186
This study examines the effects of pictorial depth on postural stability. In our first experiment, two abstract paintings by Maria Elena Vieira Da Silva (1908–1992) were used. Viewing the unaltered paintings induced greater body sway in participants than the cubist transformations of the same paintings in which depth cues were neutralized. In our second experiment, a Renaissance painting by Piero Della Francesca (c.1415–1492) was used due to its powerful representation of perspective and of sense of a recessed space in the visual field. Participants fixated either the recessed or the foregrounded area of the painting. Body sway was higher in the former case. Thus, body sway can even be modulated within the same painting according to variations of local depth information. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
20.
We report the synthesis of CdSe/CdS rod in rod core/shell heterostructures. These rods, synthesized using a seeded-growth approach, show narrow distributions of rod diameters and lengths and exhibit high emission quantum efficiencies and highly polarized emission. The degree of polarization is controlled by the inner core rod dimensions, and it is equal or up to 1.5 times higher than the polarization of equivalent sphere in rod systems. Using the method of photoselection we measure the polarization anisotropy at different excitation wavelengths and study the interplay between electronic contribution and dielectric effects in determining the absorption and emission polarization. 相似文献