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排序方式: 共有211条查询结果,搜索用时 15 毫秒
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A novel methodology to accurately estimate the cooling demand in residential units is proposed, as a means of providing a better assessment of urban heat-island effects attributable to the use of residential air-conditioning units. The methodology integrates probabilistic variations in occupant behavior, which is shown to be a significant factor in estimated residential cooling requirements. The methodology consists of two key features. The first is an algorithm that generates short-term events that are likely to occur in a residential context, based on published data on occupant behavior. The second is a Monte Carlo approach to cooling load calculations based on stochastic variations in these short-term events and in the consequent likelihood of switching air-conditioning on or off. 相似文献
204.
Aerobic batch degradation of 17beta estradiol (E2) spiked into the activated sludge liquor from a sewage treatment plant was studied; and the likely impacts of E2's initial concentrations (C0), microbial population densities (MLVSS) and temperatures (TEMPT) were examined for a variety of combinations of these three factors: C0 = 10, 30 and 50 microgl(-1); MLVSS = 1750, 875 and 435 mgl(-1); and TEMPT = 5, 20 and 35 degrees C. The results, together with those obtained through two control runs performed using a killed sludge sample, demonstrated clearly that E2 was eliminated from the aqueous phase readily under appropriate MLVSS and temperature levels, with the role of sorption by biomass being less significant. By fitting observed concentration data with a first-order rate expression, the degradation rate constants (k) under all experimental conditions were estimated. The magnitude of k changed markedly in the range of 0.23-4.79 h(-1), following a general order that the higher the MLVSS was, the higher the rate constant, and that the higher the temperature, the higher the rate constant. An obvious increasing trend of the biomass-modified average rate constant (k') with increases in the temperature was also presented: the k' values at 5, 20 and 35 degrees C were 0.79, 1.77 and 3.29l MLVSS g(-1)h(-1), respectively. Furthermore, based upon the estimated k values, the temperature coefficients (theta) over the ranges of 5-20 and 20-35 degrees C were determined. In similarity with the magnitude of theta reported for ordinary BOD-based organic matrices in domestic wastewater, the theta values of E2 varied in the range of 1.026-1.09, suggesting that the temperature impacts on the degradation rates of E2 and BOD constituents are probably similar. 相似文献
205.
Aya Suzuki Yingna Wu Akihiro Yamaguchi Hideyuki Murakami Catherine M. F. Rae 《Oxidation of Metals》2007,68(1-2):53-64
The oxidation resistance of Pt–Ir modified aluminized coatings, prepared by magnetron sputtering, was investigated. Cyclic
oxidation tests revealed that Pt–30 at%Ir and Pt–50 at%Ir modified aluminide coatings demonstrated a smaller mass change compared
with Pt, Pt–80 at%Ir and Ir modified aluminide coatings. Cross-sectional analyses following cyclic oxidation tests showed
that the TGO layer formed on the Pt modified aluminide coating surface is almost twice as thick as those on the Pt–30 at%Ir
and Pt–50 at%Ir coatings. In addition, the Pt–30 at%Ir and Pt–50 at%Ir samples had a much smoother surface than the Pt modified
coatings after cyclic oxidation, and the latter suffered from severe surface rumpling. However, when the Ir content exceeded
80 at% in Pt–Ir modified coatings, internal voids formed during cyclic oxidation. These results show that the addition of
30–50 at%Ir to Pt-modified aluminized coatings is most effective in enhancing oxidation resistance. 相似文献
206.
Tanisako A Hori A Okumura A Miyata C Kuzuryu C Obi T Yoshimura H 《Journal of electron microscopy》2005,54(4):379-383
The projection X-ray microscope utilises a very small X-ray source emitted from a thin (0.1-3 microm) target metal film excited by the focused electron beam of a scanning electron microscope. When an object is placed just below the target metal film, the diverging X-rays enlarge the shadow of the object. Because no X-ray optics such as a zone-plate is used, the focal depth is, in principle, infinitely large. We exploited this to apply projection X-ray microscopy to three-dimensional (3-D) structure analysis by means of cone-beam computed tomography. The projection images of a small arthropod (Pseudocneorhinus bifasciatus, 5 mm in length), was recorded at 3 degrees increments over the whole range (360 degrees) of a stepping-motor-controlled sample rotator. A 3-D image was reconstructed from corn-beam projections using a filtered back-projection algorithm. The reconstructed 3-D image showed in detail the internal structure of an opaque object. 相似文献
207.
Vaithilingam S. Ma T-J. Furukawa Y. Wygant I.O. Xuefeng Z. De La Zerda A. Oralkan Omer Kamaya Aya Gambhir Sanjiv s. Jeffrey R. Brooke Khuri-Yakub Butrus T. 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2009,56(11):2411-2419
In this paper, we describe using a 2-D array of capacitive micromachined ultrasonic transducers (CMUTs) to perform 3-D photoacoustic and acoustic imaging. A tunable optical parametric oscillator laser system that generates nanosecond laser pulses was used to induce the photoacoustic signals. To demonstrate the feasibility of the system, 2 different phantoms were imaged. The first phantom consisted of alternating black and transparent fishing lines of 180 μm and 150 μm diameter, respectively. The second phantom comprised polyethylene tubes, embedded in chicken breast tissue, filled with liquids such as the dye indocyanine green, pig blood, and a mixture of the 2. The tubes were embedded at a depth of 0.8 cm inside the tissue and were at an overall distance of 1.8 cm from the CMUT array. Two-dimensional cross-sectional slices and 3-D volume rendered images of pulse-echo data as well as photoacoustic data are presented. The profile and beamwidths of the fishing line are analyzed and compared with a numerical simulation carried out using the Field II ultrasound simulation software. We investigated using a large aperture (64 x 64 element array) to perform photoacoustic and acoustic imaging by mechanically scanning a smaller CMUT array (16 x 16 elements). Two-dimensional transducer arrays overcome many of the limitations of a mechanically scanned system and enable volumetric imaging. Advantages of CMUT technology for photoacoustic imaging include the ease of integration with electronics, ability to fabricate large, fully populated 2-D arrays with arbitrary geometries, wide-bandwidth arrays and high-frequency arrays. A CMUT based photoacoustic system is proposed as a viable alternative to a piezoelectric transducer based photoacoustic systems. 相似文献
208.
Fabrication of Micropatterned Self‐Oscillating Polymer Brush for Direction Control of Chemical Waves 下载免费PDF全文
Kenta Homma Tsukuru Masuda Aya Mizutani Akimoto Kenichi Nagase Kazuyoshi Itoga Teruo Okano Ryo Yoshida 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(21)
The propagation control of chemical waves via a pentagonal patterned structure in a self‐oscillating polymer brush composed of N‐isopropylacrylamide and a metal catalyst for the Belousov–Zhabotinsky (BZ) reaction is reported. The patterned self‐oscillating polymer brush is prepared by combining surface‐initiated atom transfer radical polymerization and maskless photolithography. Surface modification is confirmed by X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, 3D measuring laser microscopy, and fluorescence microscopy. The polymer brush patterns are fabricated with gaps between the pentagonal regions, and investigations on the effect of the gap distance on the BZ reaction reveal that at the appropriate distance, chemical waves propagate across the array from the plane to the corner between the patterns. Unidirectional control is achieved not only in the 1D array, but also in a 2D curved array. This patterned self‐oscillating polymer brush is a novel and advantageous approach for creating an autonomous dynamic soft interface. 相似文献
209.
Gönül Akça Ali Osman Ayaş Selda Kılıç Çetin Mustafa Akyol Ahmet Ekicibil 《Journal of Superconductivity and Novel Magnetism》2017,30(6):1515-1525
A systematic study on the effect of monovalent cation doping on structural, magnetic, and magnetocaloric properties of Pr0.85 A 0.15MnO3 (A = Ag and K) samples synthesized by a sol-gel method has been carried out. The crystal structure and morphology have been worked by X-ray diffraction (XRD) and scanning electron microscopy (SEM) imaging measurements. The XRD results indicate that both samples have orthorhombic structure. Magnetization versus temperature measurements show that our samples display a ferromagnetic-to-paramagnetic phase transition with increasing temperature. The ferromagnetic-to-paramagnetic phase transition temperature (T C) values were found as 74 and 116 K for Pr0.85Ag0.15MnO3 and Pr0.85 K 0.15MnO3, respectively. The magnetic entropy changes were evaluated from isothermal magnetization curves measured at various temperatures near T C by steps of 4 K. The values of the magnetic entropy change were determined as 0.99 and 1.39 J kg ?1 K ?1 for Pr0.85Ag0.15MnO3 and Pr0.85 K 0.15MnO3 under external field changes of 10 kOe, respectively. 相似文献
210.
A Reevaluation of the Adaptive Exponentially Weighted Moving Average Control Chart When Parameters are Estimated 下载免费PDF全文
Aya A. Aly Nesma A. Saleh Mahmoud A. Mahmoud William H. Woodall 《Quality and Reliability Engineering International》2015,31(8):1611-1622
The performance of control charts can be adversely affected when based on parameter estimates instead of known in‐control parameters. Several studies have shown that a large number of phase I observations may be needed to achieve the desired in‐control statistical performance. However, practitioners use different phase I samples and thus different parameter estimates to construct their control limits. As a consequence, there would be in‐control average run length (ARL) variation between different practitioners. This kind of variation is important to consider when studying the performance of control charts with estimated parameters. Most of the previous literature has relied primarily on the expected value of the ARL (AARL) metric in studying the performance of control charts with estimated parameters. Some recent studies, however, considered the standard deviation of the ARL metric to study the performance of control charts. In this paper, the standard deviation of the ARL metric is used to study the in‐control and out‐of‐control performance of the adaptive exponentially weighted moving average (AEWMA) control chart. The performance of the AEWMA chart is then compared with that of the Shewhart and EWMA control charts. The simulation results show that the AEWMA chart might represent a good solution for practitioners to achieve a reasonable amount of ARL variation from the desired in‐control ARL performance. In addition, we apply a bootstrap‐based design approach that provides protection against frequent false alarms without deteriorating too much the out‐of‐control performance. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献