全文获取类型
收费全文 | 80篇 |
免费 | 8篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 16篇 |
机械仪表 | 2篇 |
能源动力 | 7篇 |
轻工业 | 6篇 |
无线电 | 12篇 |
一般工业技术 | 12篇 |
冶金工业 | 9篇 |
自动化技术 | 22篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 8篇 |
2010年 | 3篇 |
2009年 | 5篇 |
2008年 | 2篇 |
2007年 | 3篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2003年 | 1篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1976年 | 1篇 |
排序方式: 共有88条查询结果,搜索用时 15 毫秒
1.
The kinetics of the transition metal-catalysed direct addition of amine NH bonds to carbon--carbon multiple bonds (hydroamination) has been explored by in situ spectroscopic techniques. From an open mass balance it was concluded that an intermediate species was formed during the cyclisation of 6-aminohex-1-yne. This species was identified as the enamine 2-methylene-piperidine, which is the primary hydroamination product. 相似文献
2.
Reproducible Enhancement of Fluorescence by Bimetal Mediated Surface Plasmon Coupled Emission for Highly Sensitive Quantitative Diagnosis of Double‐Stranded DNA 下载免费PDF全文
Nhu Hoa Thi Tran Kieu The Loan Trinh Jun‐Ho Lee Won Jung Yoon Heongkyu Ju 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(32)
Plasmonic enhancement of fluorescence from SYBR Green I conjugated with a double‐stranded DNA (dsDNA) amplicon is demonstrated on polymerase chain reaction (PCR) products. Theoretical computation leads to use of the bimetallic (Au 2 nm–Ag 50 nm) surface plasmons due to larger local fields (higher quality factors) than monometallic (Ag or Au) ones at both dye excitation and emission wavelengths simultaneously, optimizing fluorescence enhancement with surface plasmon coupled emission (SPCE). Two kinds of reverse Kretschmann configurations are used, which favor, in signal‐to‐noise ratio, a fluorescence assay that uses optically dense buffer such as blood plasma. The fluorescence enhancement (12.9 fold at maximum) with remarkably high reproducibility (coefficient of variation (CV) < 1%) is experimentally demonstrated. This facilitates credible quantitation of enhanced fluorescence, however unlikely to obtain by localized surface plasmons. The plasmon‐induced optical gain of 46 dB due to SPCE‐active dye molecules is also estimated. The fluorescence enhancement technologies with PCR enables LOD of the dsDNA template concentration of ≈400 fg µL?1 (CV < 1%), the lowest ever reported in DNA fluorescence assay to date. SPCE also reduces photobleaching significantly. These technologies can be extended for a highly reproducible and sufficiently sensitive fluorescence assay with small volumes of analytes in multiplexed diagnostics. 相似文献
3.
Ha Vu Thi Thu Nguyen Manh B. Tam Tran Nhu Thu Vu Thi Yen Pham Thi Hai Phong Pham Hong Nhiem Dao Ngoc Hung Le Quoc Hai Tran Quang 《Journal of Applied Electrochemistry》2022,52(3):607-616
Journal of Applied Electrochemistry - In this study, a sensitive and selective electrochemical sensor based on a zirconia oxide-decorated gold nanoflake nanocomposite-modified glassy carbon... 相似文献
4.
A two-cell planar stack in the Jülich F-design with solid oxide cells has been built and the reversible operation between fuel cell and electrolysis modes has been demonstrated. The cells were anode supported cells (ASC) with yttria-stabilized zirconia (YSZ) electrolytes, Ni/YSZ hydrogen electrodes and perovskite oxygen electrodes with lanthanum strontium cobalt ferrite (LSCF). This paper summarizes and discusses the preliminary experimental results on the long-term aging tests of the reversible solid oxide planar short stack for fuel cell operation (4000 h) at a current density of 0.5 A cm−2 which shows a degradation of 0.6% per 1000 h and for steam electrolysis operation (3450 h) and co-electrolysis operation of CO2 and H2O (640 h) under different current densities from −0.3 to −0.875 A cm−2 which show different degradation rates depending on current density and on steam or co-electrolysis. 相似文献
5.
6.
Tien Dat Pham Kunihiko Yoshino Nga Nhu Le Dieu Tien Bui 《International journal of remote sensing》2013,34(22):7761-7788
ABSTRACTAboveground biomass (AGB) of mangrove forest plays a crucial role in global carbon cycle by reducing greenhouse gas emissions and mitigating climate change impacts. Monitoring mangrove forests biomass accurately still remains challenging compared to other forest ecosystems. We investigated the usability of machine learning techniques for the estimation of AGB of mangrove plantation at a coastal area of Hai Phong city (Vietnam). The study employed a GIS database and support vector regression (SVR) to build and verify a model of AGB, drawing upon data from a survey in 25 sampling plots and an integration of Advanced Land Observing Satellite-2 Phased Array Type L-band Synthetic Aperture Radar-2 (ALOS-2 PALSAR-2) dual-polarization horizontal transmitting and horizontal receiving (HH) and horizontal transmitting and vertical receiving (HV) and Sentinel-2A multispectral data. The performance of the model was assessed using root mean square error (RMSE), mean absolute error (MAE), coefficient of determination (R2), and leave-one-out cross-validation. Usability of the SVR model was assessed by comparing with four state-of-the-art machine learning techniques, i.e. radial basis function neural networks, multi-layer perceptron neural networks, Gaussian process, and random forest. The SVR model shows a satisfactory result (R2 = 0.596, RMSE = 0.187, MAE = 0.123) and outperforms the four machine learning models. The SVR model-estimated AGB ranged between 36.22 and 230.14 Mg ha?1 (average = 87.67 Mg ha?1). We conclude that an integration of ALOS-2 PALSAR-2 and Sentinel-2A data used with SVR model can improve the AGB accuracy estimation of mangrove plantations in tropical areas. 相似文献
7.
Nicholas R. Krogman Arlin L. Weikel Nhu Q. Nguyen Katherine A. Kristhart Syam P. Nukavarapu Lakshmi S. Nair Cato T. Laurencin Harry R. Allcock 《应用聚合物科学杂志》2010,115(1):431-437
New biomedically erodible polymer composites were investigated. Polyphosphazenes containing the dipeptide side groups alanyl–glycine ethyl ester, valinyl–glycine ethyl ester, and phenylalanyl–glycine ethyl ester were blended with poly(lactide‐co‐glycolide) (PLGA) with lactic to glycolic acid ratios of 50 : 50 [PLGA (50 : 50)] and 85 : 15 [PLGA (85 : 15)] with solution‐phase techniques. Each dipeptide ethyl ester side group contains two N? H protons that are capable of hydrogen bonding with the carbonyl functions of PLGA. Polyphosphazenes that contain only the dipeptide ethyl ester groups are insoluble in organic solvents and are thus unsuitable for solution‐phase composite formation. To ensure solubility during and after synthesis, cosubstituted polymers with both dipeptide ethyl ester and glycine or alanine ethyl ester side groups were used. Solution casting or electrospinning was used to fabricate polymer blend matrices with different ratios of polyphosphazene to polyester, and their miscibilities were estimated with differential scanning calorimetry and scanning electron microscopy techniques. Polyphosphazenes with alanyl–glycine ethyl ester side groups plus the second cosubstituent were completely miscible with PLGA (50 : 50) and PLGA (85 : 15) when processed via solution‐casting techniques. This suggests that the hydrogen‐bonding protons in alanyl–glycine ethyl ester have access to the oxygen atoms of the carbonyl units in PLGA. However, when the same pair of polymers was electrospun from solution, the polymers proved to be immiscible. Solution‐cast miscible polymer blends were obtained from PLGA (50 : 50) plus the polyphosphazene that was cosubstituted with valinyl–glycine ethyl ester and glycine ethyl ester side groups. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
8.
Le Xuan Hien Do Thi Ngoc Minh Nguyen Thi Viet Trieu Christian Decker 《Journal of Coatings Technology and Research》2011,8(3):343-353
The influence of cashew nut shell oil (CNO), epoxidized soybean oil (ESO), castor oil (CO), and dioctyl phtalate (DOP) on
the photocrosslinking kinetics of UV curable mixtures containing an o-cresol novolac epoxy resin (CNE), a bis-cycloaliphatic diepoxide monomer (BCDE), and a triarylsulfonium salt (TAS) as a cationic
photoinitiator has been studied. The formulation with a weight ratio CNE/BCDE/TAS of 60/40/5 was found to have the highest
cure rate and the greatest final conversion of epoxy groups upon UV exposure. The presence of an unsaturated oil or of DOP
in the UV curable formulation, at a content ranging from 0.07 to 0.79 mol/kg, was shown to increase the initial polymerization
rate of the epoxy groups from 12 up to 31 mol/kg s, and the epoxy conversion after 18 s UV exposure from 80 up to 95%. It
was found that the UV cured coatings containing CNO or DOP at concentrations between 0.3 and 0.6 mol/kg and ESO at concentrations
between 0.12 and 0.19 mol/kg exhibit the best performance. These results were explained by a number of competitive factors,
mainly the effects of the chemical structure and content of the oils and of DOP on the polarity, viscosity, compatibility,
and internal filter effect of the UV curable resins, as well as by the characteristics of the tridimensional polymer networks
formed upon UV exposure. The materials produced under the optimal conditions determined in this study can be used as high
performance decorative and protective coatings and also as adhesives in different sectors of applications. 相似文献
9.
YT Zhou M Shimabukuro K Koyama Y Lee MY Wang F Trieu CB Newgard RH Unger 《Canadian Metallurgical Quarterly》1997,94(12):6386-6390
We have studied mechanisms by which leptin overexpression, which reduces body weight via anorexic and thermogenic actions, induces triglyceride depletion in adipocytes and nonadipocytes. Here we show that leptin alters in pancreatic islets the mRNA of the genes encoding enzymes of free fatty acid metabolism and uncoupling protein-2 (UCP-2). In animals infused with a recombinant adenovirus containing the leptin cDNA, the levels of mRNAs encoding enzymes of mitochondrial and peroxisomal oxidation rose 2- to 3-fold, whereas mRNA encoding an enzyme of esterification declined in islets from hyperleptinemic rats. Islet UCP-2 mRNA rose 6-fold. All in vivo changes occurred in vitro in normal islets cultured with recombinant leptin, indicating direct extraneural effects. Leptin overexpression increased UCP-2 mRNA by more than 10-fold in epididymal, retroperitoneal, and subcutaneous fat tissue of normal, but not of leptin-receptor-defective obese rats. By directly regulating the expression of enzymes of free fatty acid metabolism and of UCP-2, leptin controls intracellular triglyceride content of certain nonadipocytes, as well as adipocytes. 相似文献
10.
As the rheology of the third body does not only depend on its mechanical properties, classical discrete element simulations are not capable of modeling its flows. Consequently to take into account the third body's mechanical, thermal and physicochemical properties, an extended discrete element approach is proposed and applied to the simulation of third-body flows. Each extension of the standard DEM model is compared to experimental results. The extended model's efficiency is demonstrated by using an arbitrary physicochemical law that simulates different types of behavior observed experimentally. 相似文献