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排序方式: 共有169条查询结果,搜索用时 31 毫秒
91.
Kim MJ Jang DH Lee YI Jung HS Lee HJ Choa YH 《Journal of nanoscience and nanotechnology》2011,11(1):889-893
Phospholipid vesicles encapsulating magnetic nanoparticles (liposome complexes) have been prepared for targeting a drug to a specific organ using a magnetic force, as well as for local hyperthermia therapy. Liposome complexes are also an ideal platform for use as contrast agents of magnetic resonance imaging (MRI). We describe the preparation and characterization of liposomes containing magnetite. These liposomes were obtained by thin film hydration method and Fe3O4 nanoparticles were synthesized by coprecipitation method. They were characterized by an electrophoretic light scattering spectrophotometer, the liposome complexes were subsequently coated using chitosan. We have further investigated the ability of the above formulation for drug delivery and MRI applications. We are specifically interested in evaluating our liposome complexes for drug therapy; hence, we selected paclitaxel for the combination study. The amount of paclitaxel was measured at 227 nm using a UV-Vis spectrophotometer. Cytotoxicity of liposome complexes was treated with the various concentrations of paclitaxel in PC3 cell lines. The structure and properties of liposome complexes were analyzed by FT-IR, XRD and VSM. The particle size was analyzed by TEM and DLS. 相似文献
92.
Sang-Bok Lee Sung-Jin Hong Jin-Woo Yi Sang-Kwan Lee Yong-Ho Choa Jin-Bong Kim 《Metals and Materials International》2012,18(1):165-170
In order to develop electromagnetic (EM) wave absorbing materials in the giga-hertz (GHz) frequency range, Fe nanofibers have
been prepared by multi-nozzle electrospinning process (ESP) and heat treatments. The effects of applied voltage and feed rate
on the morphology of electrospun PVP/Fe salt nanofibers have been studied in the electrospinning process. The average diameter
and the standard deviation of electrospun nanofibers tend to decrease with the increase of the applied voltage and the decrease
of the feed rate, respectively. Through the heat treatments of calcination and H2 reduction, as-spun PVP/Fe salt has been stepwise transformed into Fe2O3, Fe3O4, and Fe phases. To evaluate the EM characteristic of the prepared Fe nanofibers, epoxy matrix composites containing Fe nanofibers
of 10 and 30 wt% have been fabricated. The Fe nanofibers have improved the EM characteristics of composites as compared to
those of nano-sized metallic particles. 相似文献
93.
Combustion of flaky aluminum with crystallohydrates containing bounded water was studied. It was found that quasi-homogeneous mixtures of Al and crystallohydrate of sodium sulphate Na2SO4·10H2O or chromium potassium alums CrK(SO4)2·12H2O were able for easy ignition and stable combustion was realized. For sodium sulphate the burning rate was measured in a broad pressure range. The area of pressures and compositions where the stable combustion occurred was found. 相似文献
94.
SiO2 coated γ-Fe2O3 nanocomposite powder has been successfully synthesized by chemical vapor condensation process and its feasibility on hyperthermic application was investigated in this study. The power loss of SiO2 coated γ-Fe2O3 nanocomposite powder which means the magnetic heating effect under alternative magnetic field was much higher than the single phase γ-Fe2O3 nano powder due to the very fine size under 20 nm and well dispersion in biologically compatible SiO2 matrix. The superparamagnetism and hyperthermic property of SiO2 coated γ-Fe2O3 nanocomposite powder were discussed in terms of microstructural development in this study. 相似文献
95.
Koch T.L. Koren U. Gnall R.P. Choa F.S. Hernandez-Gil F. Burrus C.A. Young M.G. Oron M. Miller B.I. 《Electronics letters》1989,25(24):1621-1623
Describes the fabrication and performance of the first integrated heterodyne receiver capable of actual heterodyne data reception. Integrating a continuously tunable 1.5 mu m MQW-DBR laser with a single-mode directional coupler/switch and zero-bias MQW waveguide photodetectors, the authors have achieved error-free reception of FSK-modulated pseudorandom digital code at 105 Mbit/s.<> 相似文献
96.
As the gap between the head and disk decreases and the sensitivity of recording transducers increases, the head and disk are more likely to come in contact, which may damage the recording transducer during start/stop and flying cases. One important effect associated with the intermittent head-disk contacts is the tribocharge/tribocurrent phenomenon. In this study, tribocharge and tribocurrent generation during a pico-slider/disk interaction were measured by using an electrometer. These triboelectrical properties were compared with friction force and acoustic emission signals. The electrical potential difference between the slider and the disk was caused by mechanical interactions between them. The tribocharge was generated during the slider-disk interaction and its saturation charge level was about 1 V. The tribocharge build-up level was independent of the slider-disk interaction time. However, the tribocharge decayed when there was no interaction between the slider and the disk. The decay of tribocharge was inversely proportional to the square root of time. Tribocurrent generation coincided with tribocharge generation. The tribocurrent was also independent of the slider-disk interaction time. The current level measured in this study may not reach the electrostatic discharge (ESD) damage level, but it can induce the dissociation of lubricant.This work was supported by KOSEF (Korea Science and Engineering Foundation; Grant No. R01-2003-000-10142-0) and CISD (Center for Information and Storage Device; Grant No. R11-1997-042-12001-0). 相似文献
97.
Chen-Chia Wang Trivedi S.B. Feng Jin Khurgin J. Temple D. Hommerich U. Gad E. Fow-Sen Choa Yu-Sung Wu Corder A. 《Lightwave Technology, Journal of》2001,19(5):666-672
A new coherent optical detection technique employing coherent frequency-domain reflectometry and a novel optical frequency sensor is demonstrated for high-precision optical path-length measurements. Using pulsed laser sources, an improvement of more than two orders of magnitude in spatial resolution over conventional optical coherent frequency domain reflectometry techniques is demonstrated. Varying degrees of spatial resolution ranging from several centimeters to a few hundred nanometers are achieved. High-precision distance measurement with long baseline is also presented 相似文献
98.
Fabrication process and electrical behavior of novel pressure-sensitive composites 总被引:10,自引:0,他引:10
A novel route was developed to fabricate a new pressure-sensitive composite by dispersing homogeneously conductive carbon particles in an insulating silicone rubber matrix. The composites showed a gradual change in electrical resistivity with applied pressure within percolation threshold region at a constant temperature. This type of gradual fall of resistivity with applied pressure is very important to fabricate pressure sensors. Various amounts of carbon particles were dispersed in a rubber matrix to understand the effect of volume fraction of conductive filler with applying external pressure on resistivity. A quantitative general effective media (GEM) theory was used to understand the resistivity of carbon–rubber composites system over a large range of volume fraction of carbon with applied pressure. The use of two different sizes of silicon rubber particles showed a significant effect in gradual fall of resistivity with applied pressure in the narrow range of percolation threshold. However, a large variation in resistivity from 1st measuring to 10th measuring was observed. A significant improvement in successive measuring of resistivity variation from 1st measuring to 10th measuring was observed when composites were fabricated in hexane solvent media. Finally, nano-sized Al2O3 was dispersed to control the resistivity variation upon successive measurement and to improve the mechanical properties of the composites. The material was suggested to use as unique materials as pressure sensors in practical applications mainly for robots. 相似文献
99.
Chemical constituents in particulate emissions from an integrated iron and steel facility 总被引:3,自引:0,他引:3
Tsai JH Lin KH Chen CY Ding JY Choa CG Chiang HL 《Journal of hazardous materials》2007,147(1-2):111-119
Particle emissions from four integrated iron and steel plant processes, i.e., coke making, sintering, cold forming, and hot forming, were investigated in this study. Particle compositions of 21 element species, 11 ionic species, elemental carbon (EC), organic carbon (OC) and 16 polyaromatic hydrocarbons (PAHs) were analyzed to create "fingerprints" of the particles emitted from various processes in an integrated iron and steel plant. Results indicated that element compositions (0.11-0.42 g/g), water-soluble ions (0.34-0.52 g/g), elemental carbon (0.008-0.14 g/g), organic carbon (0.02-0.06 g/g) and PAHs (0.52-6.2 mg/g) contributed to the particle mass. In general, sulfur had a higher mass contribution than the other elements, which resulted from the use of coal, flux, heavy oil, and many recycled materials in the iron and steel plant. The particle mass contribution of potassium and chlorine in the sinter plant was higher than in other processes; this may be attributed to the lower boiling point and volatility of potassium. In addition, many recycled materials were fed into the sinter plant, causing a high concentration of potassium and chlorine in the particle phase. Eight PAH compounds were analyzed in the four processes. The carcinogenic compound Benzo(a)pyrene (BaP) was detectable only in the sintering process. 相似文献
100.
Ah-Ra Lyu Tae-Hwan Kim Sun-Ae Shin Eung-Hyub Kim Yang Yu Akanksha Gajbhiye Hyuk-Chan Kwon A Reum Je Yang Hoon Huh Min Jung Park Yong-Ho Park 《International journal of molecular sciences》2021,22(16)
Although previous studies continuously report an increased risk of hearing loss in diabetes patients, the impact of the disease on the inner ear remains unexplored. Herein, we examine the pathophysiology of diabetes-associated hearing impairment and cochlear synaptopathy in a mouse model of diabetes. Male B6.BKS(D)-Leprdb/J (db/db, diabetes) and heterozygote (db/+, control) mice were assigned into each experimental group (control vs. diabetes) based on the genotype and tested for hearing sensitivity every week from 6 weeks of age. Each cochlea was collected for histological and biological assays at 14 weeks of age. The diabetic mice exerted impaired hearing and a reduction in cochlear blood flow and C-terminal-binding protein 2 (CtBP2, a presynaptic ribbon marker) expression. Ultrastructural images revealed severely damaged mitochondria from diabetic cochlea accompanied by a reduction in Cytochrome c oxidase subunit 4 (COX4) and CR6-interacting factor 1 (CRIF1). The diabetic mice presented significantly decreased levels of platelet endothelial cell adhesion molecule (PECAM-1), B-cell lymphoma 2 (BCL-2), and procaspase-9, but not procaspase-8. Importantly, significant changes were not found in necroptotic programmed cell death markers (receptor-interacting serine/threonine-protein kinase 1, RIPK1; RIPK3; and mixed lineage kinase domain-like pseudokinase, MLKL) between the groups. Taken together, diabetic hearing loss is accompanied by synaptopathy, microangiopathy, damage to the mitochondrial structure/function, and activation of the intrinsic apoptosis pathway. Our results imply that mitochondrial dysfunction is deeply involved in diabetic hearing loss, and further suggests the potential benefits of therapeutic strategies targeting mitochondria. 相似文献