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921.
922.
923.
Chan-Hee Park Leonard D. Tijing Hem Raj Pant Tae-Hyung Kim Altangerel Amarjargal Han Joo Kim Cheol Sang Kim 《Applied Physics A: Materials Science & Processing》2013,112(4):919-926
In this paper, we report an evaluation of the performance of a new stent durability tester based on the electrical potential sensing method through accelerated in vitro testing of six different nonvascular Nitinol stents simulating physiological conditions. The stents were subjected to a pulsatile loading of 33 Hz for a total of 62,726,400 cycles, at constant temperature and pressure of 35±0.5 °C and 120±4 mmHg, respectively. The electrical potential of each stent was measured in real-time and monitored for any changes in readings. After conducting test-to-fracture tests, the stents were visually checked, and by scanning electron microscopy. A sudden electrical potential drop in the readings suggests a fracture has occurred, and the only two instances of fracture in our present results were correctly determined by our present device, with the fractures confirmed visually after the test. The excellent performance of our new method shows good potential for a highly reliable and applicable in vitro durability testing for different kinds and sizes of metallic stents. 相似文献
924.
We show that the one-dimensional Oslo rice-pile model is a special case of the abelian distributed processors model. The exact steady state of the model is determined. We show that the time evolution operator
for the system satisfies the equation
where n=L(L+1)/2 for a pile with L sites. This implies that
has only one eigenvalue 1 corresponding to the steady state, and all other eigenvalues are exactly zero. Also, all connected time-dependent correlation functions in the steady state of the pile are exactly zero for time difference greater than n. Generalization to other abelian critical height models where the critical thresholds are randomly reset after each toppling is briefly discussed. 相似文献
925.
A. Mondal B. Shougaijam T. Goswami J. C. Dhar N. K. Singh S. Choudhury K. K. Chattopadhay 《Applied Physics A: Materials Science & Processing》2014,115(1):353-358
Ordered and perpendicular columnar arrays of In2O3 were synthesized on conducting ITO electrode by a simple glancing angle deposition (GLAD) technique. The as-deposited In2O3 columns were investigated by field emission gun-scanning electron microscope (FEG-SEM). The average length and diameter of the columns were estimated ~400 nm and ~100 nm, respectively. The morphology of the structure was examined by transmission electron microscopy (TEM). X-ray diffraction (XRD) analysis shows the polycrystalline nature of the sample which was verified by selective area electron diffraction (SAED) analysis. The growth mechanism and optical properties of the columns were also discussed. Optical absorption shows that In2O3 columns have a high band to band transition at ~3.75 eV. The ultraviolet and green emissions were obtained from the In2O3 columnar arrays. The P-N junction was formed between In2O3 and P-type Si substrate. The GLAD synthesized In2O3 film exhibits low current conduction compared to In2O3 TF. However, the Si/GLAD-In2O3 detector shows ~1.5 times enhanced photoresponsivity than that of Si/In2O3 TF. 相似文献
926.
Pankaj Srivastava Subhra Dhar Neeraj K. Jaiswal 《Applied Physics A: Materials Science & Processing》2014,117(4):1997-2008
The electronic transport properties of zigzag graphene nanoribbons (ZGNRs) through covalent functionalization of gold (Au) atoms is investigated by using non-equilibrium Green’s function combined with density functional theory. It is revealed that the electronic properties of Au-doped ZGNRs vary significantly due to spin and its non-inclusion. We find that the DOS profiles of Au-adsorbed ZGNR due to spin reveal very less number of states available for conduction, whereas non-inclusion of spin results in higher DOS across the Fermi level. Edge Au-doped ribbons exhibit stable structure and are energetically more favorable than the center Au-doped ZGNRs. Though the chemical interaction at the ZGNR–Au interface modifies the Fermi level, Au-adsorbed ZGNR reveals semimetallic properties. A prominent qualitative change of the I–V curve from linear to nonlinear is observed as the Au atom shifts from center toward the edges of the ribbon. Number of peaks present near the Fermi level ensures conductance channels available for charge transport in case of Au-center-substituted ZGNR. We predict semimetallic nature of the Au-adsorbed ZGNR with a high DOS peak distributed over a narrow energy region at the Fermi level and fewer conductance channels. Our calculations for the magnetic properties predict that Au functionalization leads to semiconducting nature with different band gaps for spin up and spin down. The outcomes are compared with the experimental and theoretical results available for other materials. 相似文献
927.
S. Das R. K. Singha S. Manna S. Gangopadhyay A. Dhar S. K. Ray 《Journal of nanoparticle research》2011,13(2):587-595
We have grown Ge nanocrystals (NCs) (4.0–9.0 nm in diameter) embedded in high-k HfO2 matrix for applications in floating gate memory devices. X-ray photoelectron spectroscopy has been used to probe the local
chemical bonding of Ge NCs. The analysis of Ge–Ge phonon vibration using Raman spectroscopy has shown the formation of compressively
stressed Ge NCs in HfO2 matrix. Frequency dependent electrical properties of HfO2/Ge-NCs in HfO2/HfO2 sandwich structures have been studied. An anticlockwise hysteresis in the capacitance–voltage characteristics suggests electron
injection and trapping in embedded Ge NCs. The role of interface states and deep traps in the devices has been thoroughly
examined and has been shown to be negligible on the overall device performance. 相似文献
928.
A selective, sensitive and high‐throughput liquid chromatography–tandem mass spectrometry bioanalytical method has been developed for the estimation of cycloserine in human plasma, employing cytosine as the internal standard. The extraction of the analyte was facilitated by solid‐phase extraction using 100 μL of human plasma. The separation was carried out on a BDS Hypersil C18 (150 × 4.6 mm, 5 μm) column using a mixture of 0.2% formic acid in HPLC‐grade water, methanol and acetonitrile (70:15:15, v/v/v) as mobile phase at a flow rate of 1.0 mL/min. The method was linear over the range of 0.20–20 μg/mL with r2 > 0.99. Complete validation of the method was performed as per US Food and Drug Administration guidelines and the results met acceptance criteria. Applying the present method, the clinical pharmacokinetics of cycloserine following oral administration of 250 mg cycloserine was studied under fasting conditions. Assay reproducibility was also verified by incurred sample reanalysis. 相似文献
929.
An organocatalyzed highly regioselective synthesis of substituted tetrahydrobenzofuran-4-ones based on the ring opening followed by cyclization of epoxides with enamines of 1,3-cyclohexanediones in a domino fashion is described. It is a high yielding (74–93%) synthetic protocol tolerant to a wide range of substrates. Ambient temperature, organocatalytic approach, atom-economy, and formation of water as the only by-product are some of the attractive features of the present methodology. 相似文献
930.
Kaliyaperumal Ashokkumar Muthusamy Murugan M. K. Dhanya Surya Raj D. Kamaraj 《Natural product research》2020,34(13):1919-1922
AbstractElettaria cardamomum (L.) Maton prestigiously called as Indian cardamom and is mostly cultivated in south India at higher altitudes ranging from 900 to 1400 msl. The chemical composition of dry capsules essential oil of the four distinct varieties was chemo-profiled by gas chromatography-mass spectrometry (GC-MS). Results revealed a higher concentration of major monoterpene 1, 8-Cineole ranging between 28.94% and 34.91% in PV 1 and PV 2 varieties respectively. Other monoterpenes like α-Pinene, Sabinene, Linalool, α-Terpineol and Nerol were present considerable quantities in all of the four cardamom varieties. Two sesquiterpenic constituents namely, ç-Elemene and 1,6,10-dodecatrien-3-ol (Nerolidol) were identified in all varieties. Three ester constituents were also obtained in PV 1 in which α-Terpinyl acetate (26.68%) exhibited as a major ester constituent followed by Ocimenyl acetate (0.80%) and E5-Dodecenyl acetate (0.30%). This is the first published report on the phytochemical concentration of recent varieties of Indian cardamom. 相似文献