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71.
Darius H. Torchinsky David Hsieh J.L. Luo Nuh Gedik 《Journal of Physics and Chemistry of Solids》2011,72(5):519-522
We report on band-dependent quasiparticle dynamics in the hole-doped Ba-122 pnictides measured by ultrafast pump-probe spectroscopy. In the superconducting state of the optimal and over hole-doped samples, we observe two distinct relaxation processes: a fast component whose decay rate increases linearly with excitation density and a slow component whose relaxation is independent of excitation strength. We argue that these two components reflect the recombination of quasiparticles in the two hole bands through intraband and interband processes. We also find that the thermal recombination rate of quasiparticles increases quadratically with temperature in all samples. The temperature and excitation density dependence of the decays indicates fully gapped hole bands and nodal or very anisotropic electron bands. 相似文献
72.
Numerical experiments with several variants of the original weighted essentially non‐oscillatory (WENO) schemes (J. Comput. Phys. 1996; 126 :202–228) including anti‐diffusive flux corrections, the mapped WENO scheme, and modified smoothness indicator are tested for the Euler equations. The TVD Runge–Kutta explicit time‐integrating scheme is adopted for unsteady flow computations and lower–upper symmetric‐Gauss–Seidel (LU‐SGS) implicit method is employed for the computation of steady‐state solutions. A numerical flux of the variant WENO scheme in flux limiter form is presented, which consists of first‐order and high‐order fluxes and allows for a more flexible choice of low‐order schemes. Computations of unsteady oblique shock wave diffraction over a wedge and steady transonic flows over NACA 0012 and RAE 2822 airfoils are presented to test and compare the methods. Various aspects of the variant WENO methods including contact discontinuity sharpening and steady‐state convergence rate are examined. By using the WENO scheme with anti‐diffusive flux corrections, the present solutions indicate that good convergence rate can be achieved and high‐order accuracy is maintained and contact discontinuities are sharpened markedly as compared with the original WENO schemes on the same meshes. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
73.
74.
In this paper, we develop a deterministic inventory model for deteriorating items with two warehouses by minimizing the net present value of the total cost. Deterioration rates of items in the two warehouses may be different. In addition, we allow for shortages and complete backlogging. We then prove that the optimal replenishment policy not only exists but also is unique under some condition. Further, the result reveals that the reorder interval based on the average total cost, if it exists, must be longer than that derived using net present value. Finally, we use Yang’s [H.L. Yang, European Journal of Operational Research 157 (2004) 344–356] numerical example to illustrate the model and conclude the paper with suggestions for possible future research. 相似文献
75.
Bi-Zen Hsieh Hung-Yi Chuang Liang Chao Ying-Jie Huang Po-Hao Tseng Tar-Hwa Hsieh Yu-Kai Han Ko-Shan Ho 《Polymer Degradation and Stability》2008,93(5):983-989
The first-order thermal transitions including side-chain melting, crystal-LC, biphasic chimney-like, and isotropic transitions of poly(n-undecyl isocyanate) (PUDIC) were investigated by varying its thermal history. After annealing at 140 °C for different periods of time, it leads to different degrees of backbiting degradation into n-undecyl isocyanurate trimer which behaves as a solvent for the rest non-degraded/rigid PUDIC to change into a lyotropic LC from thermotropic transition. Based on the degree of degradation, various amounts of trimers are present and the PUDIC demonstrates different types of thermal transitions found in DSC thermograms due to the variation of the non-degraded PUDIC concentration in solvent trimers. Finally, a phase diagram includes all types of crystallines, LC, and isotropic regions can be drawn according to the DSC thermograms. 相似文献
76.
77.
Tsai YH Hsieh YH Huang YB Chang JS Huang CT Wu PC 《Chemical & pharmaceutical bulletin》2010,58(11):1461-1465
The objective of this work was to develop a safe and effective delivery vehicle for topical treatment of gemcitabine. The physicochemical properties, drug release rate, drug level in plasma and bladder, and histological changes of tissue after drug administration were investigated. The electrical conductivity, mean size, and viscosity of drug-loaded microemulsions were 0.8-102.0 μS/cm, 116.8-322.5 nm, and 42.9-105.0 cps×103, respectively. Gemcitabine loaded microemulsions showed a slower and sustained release. After intravesical administration of aqueous control and microemulsions treated, the drug concentrations in plasma were 15.11 μg/ml and 2.81-12.82 μg/ml, respectively, and the accumulation in bladder were 18.27 μg and 9.12-64.16 μg, respectively. Microemulsions slightly decreased the systemic absorption and significantly enhanced the accumulation in bladder tissue. Moreover, the preliminary toxicity studies revealed no overt adverse histological changes or tissue irritation by the microemulsion application. Therefore, the microemulsions were suggested to be a promising drug carrier for intravesical chemotherapy. 相似文献
78.
A laser-based measurement system for evaluation of the scraping workpiece quality that can eliminate contact-induced measurement errors and increase measurement accuracy is proposed. The laser-based measurement system comprises a light-scattering-type triangulation laser, a computer numerical control (CNC) machine tool, and an analog-to-digital (A/D) card. The triangulation laser measures the depth of the scraping spots and the CNC machine tool locates their position. The 3D data of the scraping workpiece is then drawn using the least squares method. Cast iron and Turcite workpieces can be measured. Five parameters of the scraping workpiece, namely peak points per square inch, percentage of points, distribution of heights of points or depth of surroundings, edge shape of the grooves, and flatness, can be evaluated. The scanning rate and sampling rate of the laser-based measurement system are 100 mm/s and 10 KHz, respectively. In the future, an appliance machine based on the proposed system will be designed for the on-line detection of scraping workpieces. 相似文献
79.
Jeng-Jong Hwang Tzu-Chen Yen Bor-Tsung Hsieh Gann Ting 《Journal of Radioanalytical and Nuclear Chemistry》1999,241(3):581-587
The evaluation of the pharmacokinetics of pure, beta radiopharmaceuticals is not possible with scintigraphy. Both whole-body
autoradiography (WBAR) and Packard Instantimager, a device for rapid imaging, were used to study the whole body distribution
of γ- and β-emitting radionuclides (99mTc-MDP,99mTc-sulfur colloid, or188Re-HEDP), and results obtained from both methods were compared. The biodistribution of99mTc-MDP and188Re-HEDP were seen mainly in bones including skull, spine, and vertebrae of spine and cardiac and skeletal muscles. The99mTc-sulfur colloid localized in liver, bone marrow, and spleen. The resolution of WBAR is superior than that of Packard Instantimager.
However, the advantage of Packard Instantimager is that rapid imaging within few minutes is possible with it, while WBAR imaging
requires several hours to days. 相似文献
80.
Y Hsieh M Chintala H Mei J Agans J M Brisson K Ng W A Korfmacher 《Rapid communications in mass spectrometry : RCM》2001,15(24):2481-2487
A higher-throughput bioanalytical method based on fast-gradient (1 min run time) high-performance liquid chromatography (HPLC) coupled with tandem mass spectrometry (MS/MS) was developed for screen-type analyses of plasma samples from early drug discovery studies in support of exploratory pharmacodynamic studies. The HPLC system equipped with minibore column was interfaced with either atmospheric pressure chemical ionization (APCI) or electrospray (ESI) ionization techniques. The matrix ion suppression effect of both quantitative HPLC/MS/MS analyses was compared using the post-column infusion system. The use of the described methods provided advantages such as a shorter chromatographic region of ion suppression, less solvent consumption and shorter run times in comparison with standard analytical column HPLC/MS/MS methods. The analytical results obtained by both HPLC/MS/MS methods were in good agreement (within 15% of error) and displayed a good correlation with the pharmacodynamic outcome. 相似文献