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Lemi Türker Inci Eroglu Meral Yücel Ufuk Gündüz 《International Journal of Hydrogen Energy》2004,29(15):1643-1647
PM3 (RHF) type semiempirical quantum chemical calculations have been carried out on (nH2+Be)@C120 systems where C120 is a capped tube and n15. The results indicate that all these systems are stable but endothermic in nature. (7H2+Be)@C120 system has the lowest heat of formation value. 相似文献
13.
Hayrettin Acar Fevzi Karsli Mehmet Ozturk Mustafa Dihkan 《International journal of remote sensing》2019,40(1):138-155
Three-dimensional (3D) spatial information of object points is a vital requirement for many disciplines. Laser scanning technology and techniques based on image matching have been used extensively to produce 3D dense point clouds. These data are used frequently in various applications, such as the generation of digital surface model (DSM)/digital terrain model (DTM), extracting objects (e.g., buildings, trees, and roads), 3D modelling, and detecting changes. The aim of this study was to extract the building roof points automatically from the 3D point cloud data created via the image matching techniques with optical aerial images (with red, green, and blue band (RGB) and infrared (IR)). In the first stage of the study, as an alternative to laser scanning technology, which is more expensive than optical imaging systems, the 3D point clouds were produced by matching high-resolution images using a Semi Global Matching algorithm. The normalized difference vegetation index (NDVI) values for each point were calculated using the spectral information (RGB + IR) in the 3D point cloud data, and the points that represented the vegetation cover were determined using these values. In the second stage, existing ground and non-ground points that were free of vegetation cover were determined within the point cloud. Subsequently, only the points on the roof of the building were detected automatically using the proposed algorithm. Thus, points of the roofs of buildings located in areas with different topographic characteristics were detected automatically detected using only images. It was determined that the average values of correctness (Corr), completeness (Comp), and quality (Q) of the pixel-based accuracy analysis metrics were 95%, 98%, and 93%, respectively, in the selected test areas. According to the results of the accuracy analysis, it is clear that the proposed algorithm is very successful in automatic extraction of building roof points. 相似文献
14.
Mustafa Gazi Zainab Eniola Ojoro Hayrettin Ozan Gulcan 《Chemical Engineering Communications》2017,204(7):729-738
High-performance activated carbon-zinc oxide (Ac–ZnO) nanocatalyst was fabricated via the microwave-assisted technique. Ac–ZnO was characterized and the results indicated that Ac–ZnO is stable, had a band gap of 3.26?eV and a surface area of 603.5?m2g?1, and exhibited excellent adsorptive and degrading potentials. About 93% phenol was adsorbed within 550?min of reaction by Ac–ZnO. Impressively, a complete degradation was achieved in 90?min via a photo-Fenton/Ac–ZnO system under optimum conditions. An artificial neural network (ANN) model was developed and applied to study the relative significance of input variables affecting the degradation of phenol in a photo-Fenton process. The ANN results indicate that increases in both H2O2 and Ac–ZnO dosage enhanced the rate of phenol degradation. The highest rate constant at the optimum conditions was 0.093?min?1 and it was found to be consistent with the ANN-predicted rate constant (0.095?min?1). 相似文献
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α-Amylase was covalently immobilized onto poly(methyl methacrylate-2-hydroxyethyl methacrylate) microspheres, which were activated by using either epichlorohydrin (ECH) or cyanuric chloride (C3N3Cl3). The properties of the immobilized enzyme were investigated and compared with those of the free enzyme. For the assays carried out at 25 °C and pH 6.9, the relative activities were found to be 73.0% and 90.8% for epichlorohydrin and cyanuric chloride bound enzymes, respectively. Upon immobilization, the maximum activities were obtained at lower pH values and higher temperatures as compared with the free enzyme. Kinetic parameters were calculated as 2.51 g/L, 28.54 g/L and 15.50 g/L for Km and 1.67 × 10−3 gL−1 min−1 2.89 × 10−4 gL−1 min−1 and 1.89 × 10−3 gL−1 min−1 for Vmax for free, epichlorohydrin and cyanuric chloride bound enzymes, respectively. Enzyme activities were found to be ca. 32.7% for ECH and 41.1% for C3N3Cl3 activated matrices after storage for one month. On the other hand the free enzyme lost its activity completely within 20 days. Immobilization, storage stability and repeated use capability experiments carried out in the presence of Ca2+ ions demonstrated higher stability in the presence of these ions. The enzymes immobilized in the presence of Ca2+ ions retained 90.6% and 90.8% of the original activities even after 30 days in the case of ECH and C3N3Cl3 activations, respectively. In repeated batch experiments, i.e., 20 uses of the enzyme in 3 days; in the absence of Ca2+ ions retentions of 79.2% and 77.1% of the original enzyme activities were observed for ECH and C3N3Cl3 immobilized enzymes, respectively, whereas, in the case of addition of Ca2+ ions to the assay medium, these values were enhanced to 95.3% and 92.2%. 相似文献
17.
Hayrettin Düzcüko?lu 《Tribology International》2009,42(8):1146-1153
In polyamide based gears, thermal damage of the gear tooth surfaces occurs during gear meshing due to accumulated heat in the tooth body. In the experimental study reported in this paper, polyamide gear teeth have been modified in order to distribute the generated heat on the tooth surface by means of drilled cooling holes at different locations on the gear tooth body. The main aims of this paper were to study the effect of cooling holes on the accumulated heat on the tooth surface and on the measured wear. It was shown that the drilled cooling holes on the tooth body decreased the tooth surface temperature and led to an increase in the load carry capacity and improved wear resistance. Geometrically modified gears have showed an improved service life and a decreased surface temperature. 相似文献
18.
Efe Boran Ebru Özgür Meral Yücel Ufuk Gündüz Inci Eroglu 《International Journal of Hydrogen Energy》2012
In this study, a pilot solar tubular photobioreactor was successfully implemented for fed batch operation in outdoor conditions for photofermentative hydrogen production with Rhodobacter capsulatus (Hup−) mutant. The bacteria had a rapid growth with a specific growth rate of 0.052 h−1 in the batch exponential phase and cell dry weight remained in the range of 1–1.5 g/L throughout the fed batch operation. The feeding strategy was to keep acetic acid concentration in the photobioreactor at the range of 20 mM by adjusting feed acetate concentration. The maximum molar productivity obtained was 0.40 mol H2/(m3 h) and the yield obtained was 0.35 mol H2 per mole of acetic acid fed. Evolved gas contained 95–99% hydrogen and the rest was carbon dioxide by volume. 相似文献
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A rapid HPLC method for determination of Sudan dyes and Para Red in red chilli pepper 总被引:1,自引:0,他引:1
A rapid high-performance liquid chromatography (HPLC) system consisting of an ultraviolet-visible (UV–VIS) detector was developed for the separation and determination of Sudan dyes (I, II, III, and IV) and Para Red in red chilli peppers. The chromatographic separation was achieved on a reverse phase C18 column with isocratic elution, using a mobile phase of acetonitrile/methanol (80:20, v/v); detector was set at 506 nm. All four Sudan dyes and Para Red were separated in less than 9 min. Among 80 red chilli peppers screened, only one of them contained 0.10, 0.04, and 0.05 mg/kg Sudans I, III, and IV, respectively. No Sudan II and Para Red were detected in any of the red chilli peppers analysed. The method was ‘in-house’ validated using red chilli peppers based on following criteria: limit of detection (LOD), limit of quantification (LOQ), recovery, repeatability, reproducibility, and linearity in red chilli peppers. Depending on the dye involved, LOD and LOQ were in the range of 1.2–5.4 and 4–18 μg/kg in red chilli, respectively. The recovery, repeatability (expressed as coefficient of variation, CVr), and reproducibility (CVR) varied from 89 to 98%, from 0.82 to 4.09%, and from 1.33 to 4.65%, respectively. Linearity obtained for all dyes and Para Red were all r2 > 0.9999 (in the range of 0.01–5 mg/l). The applicability of the method to the determination of Sudan dyes and Para Red in red chilli peppers was demonstrated. This method has potential to be used for illegal Sudan dyes and Para Red in red chilli peppers and some foodstuffs due to its simple, reliable, rapid, and excellent precision. 相似文献