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1.
Demodulation of Gaussian Minimum Shift Keying (GMSK) using a limiter-discriminator is a low complexity alternative to coherent
demodulation. This so-called digital FM demodulation is followed by clock recovery, sampling, and thresholding. Conventionally,
clock recovery is done in hardware, and matched filtering is usually not possible when the Gaussian pulse is wider than a
bit duration. We propose a clock recovery technique based on discrete-time processing of the demodulated baseband signal.
This technique couples very nicely with a new maximum likelihood sequence estimator for the data that uses a whitening filter
followed by a Viterbi decoder. The entire detection algorithm can be implemented in an efficient manner on a Digital Signal
Processor (DSP). Computer simulation results are presented to show that the new algorithm performs better than the conventional
slicer by as much as 5.5 dB. 相似文献
2.
The wide electrochemical window and ion exchange properties of a room-temperature ionic liquid (RTIL) have been exploited for the extraction of palladium from nitric acid medium into ionic liquid phase — followed by direct electrodeposition of the metal from the organic phase. Extraction of palladium by commercial Aliquat 336 ionic liquids, tri-n-octylmethylammonium chloride (TOMAC) and tri-n-octylmethylammonium nitrate (TOMAN), was studied as a function of [HNO3], [NO3−] and [TOMAN]. The distribution ratio (DPd(II)) of palladium in TOMAN increased with an increase in the concentration of nitric acid and passed through a maximum at 1.0 M nitric acid. In contrast, the DPd(II) value of palladium in TOMAC decreased continuously with an increase in the concentration of nitric acid. Substantial amounts of water and nitric acid were also co-extracted into the organic phase with palladium. 相似文献
3.
The kinetics of polymerization of ?‐caprolactone (CL) in bulk was studied by irradiating with microwave of 350 W and frequency of 2.45 GHz with different cycle‐heating periods (30–50 s). The molecular weight distributions were determined as a function of reaction time by gel permeation chromatography. Because the temperature of the system continuously varied with reaction time, a model based on continuous distribution kinetics with time/temperature‐dependent rate coefficients was proposed. To quantify the effect of microwave on polymerization, experiments were conducted under thermal heating. The polymerization was also investigated with thermal and microwave heating in the presence of zinc catalyst. The activation energies determined from temperature‐dependent rate coefficients for pure thermal heating, thermally aided catalytic polymerization, and microwave‐aided catalytic polymerization were 24.3, 13.4, and 5.7 kcal/mol, respectively. This indicates that microwaves increase the polymerization rate by lowering the activation energy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1450–1456, 2004 相似文献
4.
The enzymatic degradability of poly(vinyl acetate) was investigated in toluene solutions at various temperatures with hog pancreas lipase. The polymer degraded by specific scission to yield oligomeric products with a molecular weight of 700. Continuous distribution kinetics were used to determine the rate coefficients. The variation of the rate coefficients with the temperature indicated an optimum at 55°C. The p‐toluene sulfonic acid catalyzed degradation of poly(vinyl acetate) was also investigated. The degradation mechanism was random chain scission, and the energy of activation for degradation was determined from the variation of the rate coefficients with the temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2579–2582, 2003 相似文献
5.
Results of measurement of the density and the glass transition temperature (T
g) on 25 glass compositions of the As-AI-Te system are reported and discussed. A linear increase of density and a decrease ofT
g are seen with increasing As content across the AsAlTe4- As2Te3 tie-line compositions. In the density-composition and mean atomic volume-composition dependences for the As
x
,Al5Te95–x
, As
x
Al8Te92–x
and As
x
Al12Te88–x
glasses, a change in slope is seen at the respective tie-line compositions, indicating chemical ordering in these glasses. When the dependence of density on the average coordination numberZ are considered, the effects of chemical ordering are obscured; instead, the effects of topological nature emerge, with changes in slope at the topological thresholds ofZ2.40 andZ2.67. The results further indicate that the dependence of mean atomic volumev onZ is controlled by the Te content in these glasses. Due to this, the generally observed features in the dependence ofv onZ for chalcogenide glasses, namely a minimum inv forZ2.40, a peak inv forZ2.67 and a decrease ofv forZ > 2.67, are suppressed. 相似文献
6.
Results of measurement of elastic modulii on As-Sb-Se glasses are reported and their composition dependence discussed. The
Young’s and the shear modulii lie in the range of 170–210 and 65–80 kb respectively. These values are typical of chalcogenide
glasses. For (As, Sb)40Se60 glasses, the modulii increase monotonically with increasing Sb2Se3 content. The observed composition dependence of the modulii for the As
x
Sb15Se85 −x
glasses is examined in terms of the chemically ordered structural units in the glasses. 相似文献
7.
The effect of microwave heating on the iodine-catalyzed acetylation of rubberwood with acetic anhydride has been investigated. Microwave radiation was used as the heating source for modifying specimens saturated with acetic anhydride in bulk solution (excess of reagent) and impregnated specimens (limited supply of anhydride). Extent of modification of wood was expressed in terms of weight percent gain (WPG) and modification was characterized using FTIR spectroscopy. In bulk solution, microwave radiations were primarily absorbed by anhydride solutions for heating purposes and a moderate WPG was obtained. However, when microwave heating was used to modify impregnated wood specimens under no excess of anhydride, a significant enhancement in degree of modification was achieved within a few minutes. The modified wood exhibited good anti-swelling efficiency. 相似文献
8.
Anila Rajan Giridhar R. Nair 《International Journal of Food Science & Technology》2010,45(10):2023-2031
Peanut α‐galactosidase was immobilised in calcium alginate beads and used to hydrolyse the flatulence‐causing oligosaccharides, raffinose and stachyose, in soya milk in batch and in packed bed reactor with recycle. The immobilised enzyme exhibited a slightly lower activity than the free enzyme. The activity yield of immobilised α‐galactosidase was 75.1% and the immobilisation yield was 82.6%. Batch hydrolysis using immobilised enzyme at 55 °C resulted in 96% reduction in the oligosaccharides after 12 h. For the continuous process, a packed bed reactor with recycle was used. More than 98% of the oligosaccharides were hydrolysed after 6 h of reaction at 55 °C. The immobilised enzyme also proved to be stable up to three repeated hydrolysis reactions. 相似文献
9.
Wighmal Kosheen Peddi Giridhar Apoorva Kumar Naveen Amin S. Intekhab Anand Sunny 《SILICON》2022,14(11):5951-5959
Silicon - Through this paper, we discuss how Tunnel Field Effect Transistors can be utilized for the detection of biomaterials hence acting as a biosensor. The device proposed is a 3-D Doping less... 相似文献
10.
Simultaneous removal of nitrate and arsenic from drinking water sources utilizing a fixed-bed bioreactor system 总被引:1,自引:0,他引:1
A novel bioreactor system, consisting of two biologically active carbon (BAC) reactors in series, was developed for the simultaneous removal of nitrate and arsenic from a synthetic groundwater supplemented with acetic acid. A mixed biofilm microbial community that developed on the BAC was capable of utilizing dissolved oxygen, nitrate, arsenate, and sulfate as the electron acceptors. Nitrate was removed from a concentration of approximately 50 mg/L in the influent to below the detection limit of 0.2 mg/L. Biologically generated sulfides resulted in the precipitation of the iron sulfides mackinawite and greigite, which concomitantly removed arsenic from an influent concentration of approximately 200 ug/L to below 20 ug/L through arsenic sulfide precipitation and surface precipitation on iron sulfides. This study showed for the first time that arsenic and nitrate can be simultaneously removed from drinking water sources utilizing a bioreactor system. 相似文献