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排序方式: 共有378条查询结果,搜索用时 15 毫秒
1.
《Ceramics International》2019,45(13):16387-16398
In this study, an ultraviolet (355 nm) laser processing system was developed to anneal aluminum-doped zinc oxide (AZO) thin films at room temperature in an air atmosphere; in this system, two key parameters, laser fluence and annealing speed, were varied. The structural properties of the films were thoroughly examined using field emission scanning electron microscopy, atomic force microscopy, and X-ray diffraction (XRD). The results showed that the laser fluence not only influenced the structural properties of the films, but also improved the crystallinity of the films after the laser annealing process, with minimal changes in the thickness of the films and the concentration of the elements in the films. The root mean square surface roughness (Rrms) of the films gradually increased as the laser fluence increased. Moreover, according to the XRD pattern of the films, the intensity of the main peak corresponding to the (002) direction increased as the laser fluence increased. The average crystallite size (20 nm) of the annealed films, determined using the Scherrer equation, was smaller than that of the as-deposited thin film (22 nm) due to the low temperature effect in the laser annealing process.  相似文献   
2.
《Ceramics International》2022,48(5):6124-6130
The behaviour of the promising glass sealant 54.4SiO2-13.7Na2O-1.7K2O-5.0CaO-12.4MgO-0.6Y2O3-11.3Al2O3-0.9B2O3 for solid oxide fuel cells (SOFCs) under SOFC operating conditions was studied. First, the kinetics of the crystallisation processes at the operating temperature (850 °C) was discussed (maximum exposure time of 1000 h), and the effect of crystallisation on the coefficient of thermal expansion (CTE) of the sealant was studied. Furthermore, the degradation processes at the interface of the glass sealant and functional SOFC materials (Crofer 22 APU, YSZ, and NiO(Ni)-YSZ) during exposure to 850 °C in oxidising and reducing atmospheres for 500 h were studied. The tests demonstrated good performance of the sealant studied and possibility of its application in SOFCs.  相似文献   
3.
《Ceramics International》2022,48(7):9400-9406
In the present study, we prepared vacancy-engineered V2O5-x films for electrochromic (EC) applications. To investigate the vacancy effect of V2O5-x films with high EC performance capabilities, precursor concentrations of V-based sol solutions were varied at 1 wt%, 5 wt%, and 10 wt%. Among them, V2O5-x films with a precursor concentration of 5 wt% (V2O5-5wt%) showed superior EC performance outcomes due to the (001)-plane-oriented crystal structure, which provides high electrical conductivity with the oxygen vacancy (Vo). In addition, the gravel-like uniform surface morphology with the optimized film thickness provides a stable electrochemical reaction during the EC measurement. As a result, V2O5-5wt% exhibited fast switching speeds (2.1 s for coloration and 3.6 s for bleaching), high transmittance modulation (ΔT) (51.32%), high coloration efficiency (CE) (52.3 cm2/C), and excellent cycle stability (85.85% ΔT retention after 500 cycles). In addition, V2O5-5wt% showed energy storage capability of 443.7 F/g at a current density of 2 A/g, thus proving its potential for use in multi-functional applications. Therefore, these results provide valuable insight related to the engineering of vacancies in EC films to achieve high-performance EC devices and additional multi-functional applications.  相似文献   
4.
《Ceramics International》2020,46(17):26784-26789
Effect of sintering temperature on the physical and mechanical properties of synthesized B-type carbonated hydroxyapatite (CHA) over a range of temperature in CO2 atmosphere has been investigated. The B-type CHA in nano size was synthesized at room temperature by using a direct pouring wet chemical precipitation method. The synthesized CHA powders were subsequently consolidated by sintering treatment from 800 to 1100 °C. The sintered CHA samples were evaluated using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrometry, X-ray fluorescence (XRF), carbon-hydrogen-nitrogen-sulfur-oxygen (CHNS/O) elemental analyzer, Field emission scanning electron microscopy (FESEM), and Vicker's indentation technique. The results obtained from XRD and FESEM indicated that the synthesized B-type CHA powders were nanometer in size. The crystallinity and crystallite size of the sintered CHA samples were increased due to increasing sintering temperature. The heat treatment between 800 °C and 1000 °C has resulted in coarsening and increased hardness of the sintered CHA samples. However, these properties began to deteriorate when sintering beyond 1100 °C due the formation of calcium oxide.  相似文献   
5.
Biogas utilization in fuel cell technology and hydrogen generation is a modern and economically viable approach. A pretreatment step prior to anaerobic digestion (AD) is obligatory to increase the hydrolysis, solubilize the complex matter present in organic fraction of municipal solid waste (OFMSW) and to achieve higher yield of biogas. This study was intended to find out the effects of thermal, chemical and thermochemical pretreatments on the properties and structure of OFMSW and also on biogas production. There was an increase in chemical oxygen demand of 6.87, 1.61 and 11.60% for thermal, chemical and thermochemical pretreatments, respectively. Also, the content of volatile solids was reduced by 2.36% by thermochemical pretreatment. FTIR, XRD and SEM analysis revealed that these pretreatments also caused chemical and morphological changes on the substrate, as a result reduced its crystallinity and enhanced the rate of hydrolysis. A significant increase of 54% in biogas yield was achieved after thermochemical pretreatment in comparison to untreated OFMSW sample.  相似文献   
6.
探讨部分糊化淀粉浆液黏度对浆液性能影响的规律。以玉米淀粉为原料,采用蒸汽升温方式分别在62℃~67℃制备了6种不同黏度的部分糊化淀粉浆液,对浆液的黏度、糊化度、结晶度、粒径和膨胀势进行测试,并应用SPSS统计软件的相关分析与线性回归分析功能对测试结果进行了相关性分析。结果表明:部分糊化淀粉浆液的黏度与结晶度呈负相关,结晶度随黏度的增大而降低;黏度与平均粒径、膨胀势呈极显著正相关,平均粒径和膨胀势值均随黏度的增加而明显增大;黏度与平均粒径、膨胀势呈明显的线性关系。认为通过相关性分析可以建立起部分糊化淀粉浆液的评价分析方法,运用此方法,可以直观、有效地对部分糊化淀粉浆液黏度性质进行评价分析。  相似文献   
7.
用溶液接枝聚合的方法在线型低密度聚乙烯(LLDPE)上接枝聚合极性单体甲基丙烯酸甲酯(MMA)制备LLDPE-g-PMMA,研究了反应时间、单体用量和引发剂用量对接枝反应的影响。结果表明,随着引发剂和单体量的增加,聚合物的接枝率增加,当引发剂质量分数为0.48%,单体比率为150%时,接枝率将达到26.1%。利用红外光谱(FTIR)、核磁共振碳波谱仪(13C-NMR)对其进行结构表征,证明PMMA分子链被接枝聚合到LLDPE上。使用X射线衍射仪(XRD)、差示扫描量热仪(DSC)对接枝聚合物的结晶性能进行了分析,发现接枝聚合没有改变晶型,但结晶焓由61.39 J/g降低到47.18 J/g。  相似文献   
8.
This paper demonstrates two different pretreatment protocols for oil palm trunks (OPT); steam-alkali-chemical (SAC) and microwave-alkali (Mw-A) method. The composition, morphology, structure and crystallinity of OPT before and after pretreatment were analyzed. The effectiveness of the pretreated methods was investigated by performing enzymatic saccharification on the OPT. The physiochemical factors namely: enzyme ratio (cellulase to β-glucosidase), pH, temperature and substrate loading (w/v) on enzymatic saccharification were also investigated. The pre-determined optimal conditions were then used for further enzymatic hydrolysis of raw and pretreated OPT substrates. The results revealed a huge degree of reduction in lignin, up to 89% for SAC treated OPT and at least 15% for Mw-A treated OPT sample as compared to untreated ones. High glucose accumulation (79.4%) was obtained after 72 h saccharification for both pretreated OPT samples.  相似文献   
9.
A novel peptide-based gemini surfactant, namely, sodium dilauramidoglutamide lysine (DLGL) was employed to fabricate a stable nanoemulsion system for the delivery of hydrophobic bioactive ceramide-2 molecules. The phase properties and morphology and stability of the nanoemulsion were investigated by focusing on the interaction between DLGL and ceramide-2 molecules. The investigation of the phase properties of the mixture of DLGL and ceramide-2 by X-ray diffraction, differential scanning calorimetry, and Fourier transform infrared spectroscopy revealed remarkable reduction in the crystallinity of ceramide-2 due to the presence of DLGL. The spherical shape and nanometer size of nanoemulsions emulsified by DLGL were characterized by scanning electron microscopy and transmission electron microscopy. The nanoemulsions prepared using DLGL exhibited significant improvement in the dispersion stability without any significant changes in the particle sizes even after storing them for a month at 50 °C. The results indicated that DLGL readily associated with ceramide-2 to form a relatively stable structure. The steric hindrance of DLGL and molecular rearrangement of DLGL and ceramide-2 attributed to a break in the continuity of the molecular assembly of ceramide-2, which hampered its crystallinity.  相似文献   
10.
采用钴源以剂量率为2.5 k Gy·h~(-1)的γ射线对超高分子量聚乙烯(Ultra-high Molecular Weight Polyethylene,UHMWPE)片材在空气、水、甲醇和乙醇氛围中进行了辐照,吸收剂量范围为0 200 k Gy。通过机械性能、凝胶含量、差示扫描量热仪(Differential Scanning Calorimetry,DSC)、傅里叶变换红外光谱仪(Fourier Transform Infrared Spectrometer,FTIR)等对不同辐照氛围中辐照前后UHMWPE样品进行了测试和表征。机械性能测试结果表明,在空气中UHMWPE的断裂伸长率随吸收剂量呈幂指数下降,同时屈服强度略有下降,而在水、甲醇、乙醇为辐照体系中UHMWPE的断裂伸长率随吸收剂量也是呈下降趋势,但下降的程度依次减轻,同时屈服强度基本保持不变;DSC测试结果显示,在空气氛围中,随着吸收剂量的增加,UHMWPE样品的初始熔融温度、熔点、结晶温度和结晶度逐渐降低;而在空气、水、甲醇和乙醇氛围中,UHMWPE样品的初始熔融温度、熔点和结晶度依次上升;红外光谱测试结果显示在空气中辐照,UHMWPE样品表面随着吸收剂量的增加其氧化程度加重,而在水、甲醇和乙醇中辐照UHMWPE分子链生成了不饱和的分子双键。  相似文献   
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