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排序方式: 共有313条查询结果,搜索用时 15 毫秒
1.
Karimi Bayan Chang Yu-Cheng Pekola Jukka P. 《Journal of Low Temperature Physics》2022,207(3-4):220-225
We discuss the temperature dependence of a common low temperature local thermometer, a tunnel junction between a superconductor and a normal metal (NIS junction). Towards the lowest temperatures its characteristics tend to saturate, which is usually attributed to selfheating effects. In this technical note, we reanalyze this saturation and show that the temperature independent subgap current of the junction alone explains in some cases the low temperature behavior quantitatively.
相似文献2.
3.
The Synthesis of Sulfated Titanium Oxide Nanotubes 总被引:1,自引:0,他引:1
Chiu-Hsun Lin Shu-Hua Chien Jiunn-Hsing Chao Chyi-Yang Sheu Yu-Cheng Cheng Ya-Jean Huang Chih-Hsiang Tsai 《Catalysis Letters》2002,80(3-4):153-159
TiO2 nanotubes can be prepared in gram quantities by treating anatase TiO2 powder with concentrated NaOH solution. These TiO2 nanotubes acquired strong acidity after being impregnated with sulfuric acid solution and calcined at 300 °C. The anatase TiO2 powder used to prepare the nanotube did not catalyze the esterification between cyclohexanol and acetic acid, while sulfated TiO2 nanotubes were very reactive toward the esterification reaction. 相似文献
4.
5.
Te-Yu Wei Shih-Yuan Lu Yu-Cheng Chang 《Journal of the Chinese Institute of Chemical Engineers》2007,38(5-6):477-481
Tin oxide–silica composite aerogels were successfully prepared with a co-fed precursor sol–gel process. The crystallinity of the tin oxide nanoparticles, embedded in the mesoporous SiO2 network, was improved with increasing the post-reaction thermal treatment temperature. The composite aerogels exhibited a rich photoluminescence (PL) emission contributed by both SnO2 and SiO2. The PL peak of 346 nm was from the near band edge emission of the tin oxide nanoparticles, and the ones located at 310 and 476 nm were attributable to the oxygen deficiencies of the silica network. Three more emission peaks, 387, 432, and 522 nm, were observed, with the 387 nm peak contributed by the oxygen vacancies VO++, the 432 nm peak by the Sn interstitials, and the 522 nm peak by the oxygen vacancies VO+, respectively, of the tin oxide nanoparticles. The intensities of these three defect level emissions were found decreased, as compared to that of the near band edge emission, with increasing the post-reaction thermal treatment temperature as the tin oxide crystallinity improved. 相似文献
6.
ROI-based Watermarking Scheme for JPEG 2000 总被引:1,自引:0,他引:1
Yu-Cheng Fan Arvin Chiang Jan-Hung Shen 《Circuits, Systems, and Signal Processing》2008,27(5):763-774
A new region of interest (ROI)-based watermarking method for JPEG 2000 is presented. The watermark is embedded into the host
image based on the characteristics of the ROI to protect rights to the images. This scheme integrates the watermarking process
with JPEG 2000 compression procedures. Experimental results have demonstrated that the proposed watermark technique successfully
survives JPEG 2000 compression, progressive transmission, and principal attacks. 相似文献
7.
Te-Yu Wei Tso-Fu Chang Shih-Yuan Lu Yu-Cheng Chang 《Journal of the American Ceramic Society》2007,90(7):2003-2007
Monolithic silica aerogels with thermal conductivity as low as 0.036 W·(m·K)−1 and porosity as high as 97% were successfully prepared by ambient pressure drying through a multiple modification approach. This approach may replace the more costly and dangerous operation of supercritical drying. The tetraethoxysilane (TEOS)-derived wet gel was made hydrophobic with multiple treatments of trimethylchlorosilane and dried under ambient pressure. The multiple treatments were found to be necessary to achieve sufficient modification of the wet gel for reduction in drying-induced surface tension force to maintain product integrity and high porosity. Comparisons in nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy for surface bonding and contact angle measurement for hydrophobicity between the no, single, and multiple surface modification (MSM) samples were conducted to reveal the difference in the extent of the resulting surface modification. In conclusion, the MSM procedure reduced the volume shrinkage, increased the monolithicity and porosity, and lowered the thermal conductivity of the resulting aerogels. 相似文献
8.
In this paper, we report a microfluidic chip containing a cross-junction channel for the manipulation of UV-photopolymerized
microparticles. Hydrodynamic-focusing is used to form a series of using 365 nm UV light to solidify the hydrogel droplets.
We were able to control the size of the hydrogel droplets from 75 to 300 μm in diameter by altering the sample and by changing
the flow rate ratio of the mineral oil in the center inlet channel to that of the side inlet channels. We found that the size
of the emulsions increases with an increase in average velocity of the dispersed phase flow (polymer solution flow). The size
of the emulsions decreases with an average velocity increase of the continuous phase flow (mineral oil flow). Experimental
data show that the emulsions are very uniform. The developed microfluidic chip has the advantages of ease of fabrication,
low cost, and high throughput. The emulsions generated are very uniform and have good regularity. 相似文献
9.
10.
Chia-Hsien?Yeh Ying-Chieh?Chen Yu-Cheng?LinEmail author 《Microfluidics and nanofluidics》2011,11(3):245-253
This study successfully uses the micro-mixers and flow-focusing devices, which are integrated into a gradient-microfluidic
droplet generator, to generate the different sizes of the droplets with different concentrations simultaneously and applies
these microcapsules for drug release. The sizes of these four types of droplet with different concentrations are uniformity
with a coefficient of variation less than 5% and can be precisely controlled by adjusting the water phase flow rate and oil
phase flow rate. Moreover, Ca-alginate microcapsules with different concentrations of the bovine serum albumin are used for
uniform size drug release, and the Ca-alginate microcapsule size is from 60 to 105 μm in diameter. This developed microfluidic
chip has the advantages of actively controlling the droplet diameter, simultaneously generating uniform-sized droplets with
different concentrations, and having a simple process and a high throughput. This preparation approach for Ca-alginate microcapsules
of four different concentrations will provide many potential applications for drug delivery and pharmaceutical area. 相似文献