Yingying Zhang  Chris J. Sheehan  Junyi Zhai  Guifu Zou  Hongmei Luo  Jie Xiong  Y. T. Zhu  Q. X. Jia 《Advanced materials (Deerfield Beach, Fla.)》2010,22(28):3027-3031

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Chris E. SveenYujun Shi 《Thin solid films》2011,519(14):4447-4450

The effect of filament temperature and deposition time on the formation of tungsten silicide upon exposure to the SiH₄ gas in a hot wire chemical vapor deposition process was studied using the techniques of cross-sectional scanning electron microscopy and Auger electron spectroscopy. At a relatively low temperature of 1500 °C, the decomposition of WSi₂ phase and the diffusion of Si towards the silicide/W interface produce a thick W₅Si₃ layer. The diffusional nature leads to a parabolic rate law for silicide growth. An exponential decrease of silicide thickness with temperature between 1600 and 2000 °C illustrates the dominance of Si evaporation at higher temperatures (T ≥ 1600 °C) over the silicide formation.  相似文献   

    

Rajiv Giridharagopal  Guozheng Shao  Chris Groves  David S. Ginger 《Materials Today》2010,12(9):50-56

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Constantin Pistol  Vincent Mao  Viresh Thusu  Alvin R. Lebeck  Chris Dwyer 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(7)

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Schreiber S  Savla M  Pelekhov DV  Iscru DF  Selcu C  Hammel PC  Agarwal G 《Small (Weinheim an der Bergstrasse, Germany)》2008,4(2):270-278

The use of magnetic force microscopy (MFM) to detect probe-sample interactions from superparamagnetic nanoparticles in vitro in ambient atmospheric conditions is reported here. By using both magnetic and nonmagnetic probes in dynamic lift-mode imaging and by controlling the direction and magnitude of the external magnetic field applied to the samples, it is possible to detect and identify the presence of superparamagnetic nanoparticles. The experimental results shown here are in agreement with the estimated sensitivity of the MFM technique. The potential and challenges for localizing nanoscale magnetic domains in biological samples is discussed.  相似文献   

    

Owen CA  Notingher I  Hill R  Stevens M  Hench LL 《Journal of materials science. Materials in medicine》2006,17(11):1019-1023

This review summarises progress in Raman spectroscopy and its application in diagnostics, toxicological testing and tissue engineering. Applications of Raman spectroscopy in cell biology are in the early stages of development, however, recent publications have demonstrated its utilisation as a diagnostic and development tool with the key advantage that investigations of living cells can be performed non-invasively. Some of the research highlighted here demonstrates the ability of Raman spectroscopy to accurately characterise cancer cells and distinguish between similar cell types. Many groups have used Raman spectroscopy to study tissues, but recently increased effort has gone into single cell analysis of cell lines; the advantages being that cell lines offer ease of handling and increased reproducibility over tissue studies and primary cells. The main goals of bio-Raman spectroscopy at this stage are twofold. Firstly, the aim is to further develop the diagnostic ability of Raman spectroscopy so it can be implemented in a clinical environment, producing accurate and rapid diagnoses. Secondly, the aim is to optimise the technique as a research tool for the non-invasive real time investigation of cell/material interactions in the fields of tissue engineering and toxicology testing.  相似文献   

    

Xiaoyu Li  Thomas Scott  Shao Yang  Chris Cromer  Marla Dowell 《Journal of research of the National Institute of Standards and Technology》2004,109(4):429-434

We briefly explain the fundamentals of detector nonlinearity applicable to both electrical and optical nonlinearity measurements. We specifically discuss the attenuation method for optical nonlinearity measurement that the NIST system is based upon, and we review the possible sources of nonlinearity inherent to thermal detectors used with high-power lasers. We also describe, in detail, the NIST nonlinearity measurement system, in which detector responsivity can be measured at wavelengths of 1.06 µm and 10.6 µm, over a power range from 1 W to 1000 W. We present the data processing method used and show measurement results depicting both positive and negative nonlinear behavior. The expanded uncertainty of a typical NIST high-power laser detector calibration including nonlinearity characterization is about 1.3 %.  相似文献   

    

Irwin CR  McCullough KC  Jones DS 《Journal of materials science. Materials in medicine》2003,14(10):825-832

This study describes the formulation, physicochemical and mucoadhesive properties and in in vitro/in vivo release of chlorhexidine from mucoadhesive, polymeric compacts, designed for application within the oral cavity. Compacts were prepared by direct compression of mixtures containing 100 mg sodium carboxymethylcellulose (NaCMC), 25 mg hydroxyethylcellulose (HEC)/75 mg polyacrylic acid (PAA) and 75 mg HEC/25 mg PAA. The mechanical and mucoadhesive properties of the drug-loaded compacts were examined using a texture analyzer in compression and tension modes, respectively. Evaluation of mucoadhesion was performed using a mucin-coated gauze substrate. In vitro release of chlorhexidine was performed under sink conditions (phosphate buffered saline, pH 7.0, 37 °C) using a Caleva 7ST dissolution apparatus. Salivary chlorhexidine levels were determined following intra-oral placement of drug-containing formulations. Quantification of the mass of chlorhexidine released both in vitro and in vivo was performed using HPLC with ultraviolet detection. Furthermore, the in vivo acceptability of the various polymeric compacts was assessed in volunteers using standard questionnaires. Compacts composed of HEC/PAA exhibited greater in vivo retention than those composed of NaCMC. Compacts composed of 25 mg PAA and 75 mg HEC displayed greatest patient acceptability. Introduction of chlorhexidine into these compacts did not significantly compromise either the work required for compact fracture or the in vitro mucoadhesion. Controlled release of chlorhexidine from these compacts was observed both in vitro and in vivo, the concentration of chlorhexidine in saliva exceeding the minimum inhibitory concentration of the common oral pathogens over the study period. In light of the patient acceptability and in vivo performance, it is suggested that the compact composed of 25 mg PAA/75 mg HEC containing 10 mg chlorhexidine offers considerable promise for use as an antimicrobial agent in the oral cavity.  相似文献   

    

Bradley  Brendan P.; Gossop  Michael; Brewin  Chris R.; Phillips  Grania; Green  Lynette 《Canadian Metallurgical Quarterly》1992,60(3):470

Investigated whether attributions of opiate addicts would predict both their ability to abstain from future use and their reactions to abstinence violations. Measures of generalized beliefs about responsibility for positive and negative outcomes and specific attributions about relapse episodes were elicited from 80 addicts at the time of admission for inpatient detoxification and treatment. Addicts who at admission attributed to themselves greater responsibility for negative outcomes and who attributed relapse episodes to more personally controllable factors were subsequently (at 6-mo follow-up) more likely either to be completely abstinent or to contain the effects of temporary lapses into opiate use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

  总被引：6，自引：0，他引：6  

Miao XS  Metcalfe CD 《Analytical chemistry》2003,75(15):3731-3738

A quantitative method is described for solid-phase extraction (SPE) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous analysis of carbamazepine and its five metabolites, 10,11-dihydro-10,11-epoxycarbamazepine, 10,11-dihydro-10,11-dihydroxycarbamazepine, 2-hydroxycarbamazepine, 3-hydroxycarbamazepine, and 10,11-dihydro-10-hydroxycarbamazepine. An SPE procedure was used to concentrate target compounds from aqueous samples collected from sewage treatment plant (STP) wastewater and surface water. Extracts were analyzed using electrospray LC-MS/MS with time-scheduled selected reaction monitoring. The recoveries of the analytes were 83.6-102.2% from untreated sewage (influent), 90.6-103.5% from treated sewage (effluent), and 95.7-102.9% from surface water samples. The instrumental detection limits were 0.8-4.8 pg for the analytes. Matrix effects were investigated for the analytes in HPLC-grade water, surface water, and STP influent and effluent. Ion suppression increased for analytes in order of surface water to STP effluent to STP influent, but no ion suppression was observed for analytes in HPLC-grade water. The developed method was validated by analysis of environmental aqueous samples: STP influent and effluent and surface water. Carbamazepine and all five metabolites were detected in STP influent and effluent samples. Only carbamazepine and 10,11-dihydro-10,11-dihydroxycarbamazepine were detected in the surface water sample. Notably, 10,11-dihydro-10,11-dihydroxycarbamazepine was detected at approximately 3 times higher concentrations than the parent drug, carbamazepine, in all of the aqueous samples. To our knowledge, this is the first report on the simultaneous determination of carbamazepine and its metabolites in environmental samples.  相似文献