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971.
We fabricated nano-carbon (NC) doped MgB2 bulks using an in situ process in order to improve the critical current density (Jc) under a high magnetic field and evaluated the correlated effects of the doped carbon content and sintering temperature on the phase formation, microstructure and critical properties. MgB2−xCx bulks with x = 0 and 0.05 were fabricated by pressing the powder into pellets and sintering at 800 °C, 900 °C, or 1000 °C for 30 min.We observed that NC was an effective dopant for MgB2 and that part of it was incorporated into the MgB2 while the other part remained (undoped), which reduced the grain size. The actual C content was estimated to be 68–90% of the nominal content. The NC doped samples exhibited lower Tc values and better Jc(B) behavior than the undoped samples. The doped sample sintered at 900 °C showed the highest Jc value due to its high doping level, small amount of second phase, and fine grains. On the other hand, the Jc was decreased at a sintering temperature of 1000 °C as a result of the formation of MgB4 phase.  相似文献   
972.
Abstact  A scintillating fiber-optic dosimeter has many advantages such as real-time readout, high-resolution measurement, water-equivalence and no corrections for temperature, pressure and humidity. Organic scintillator which has water or tissue equivalent characteristics is very important to measure absorbed dose, dose rate and dose distributions exactly without any corrections and due to its small size, the sensitive volume enables accurate dose measurements in regions of high dose gradients with high spatial resolution. In this study, a scintillating fiber-optic dosimeter with an organic scintillator is fabricated to measure high-energy photon beam from a clinical linear accelerator. And we have measured linear responses of a fiber-optic dosimeter according to dose rates and monitor units of a clinical linear accelerator. Also, a percent depth dose curve for 6MV photon beam with different field sizes are obtained.  相似文献   
973.
974.
Epidemiological studies have suggested an association between pesticide exposure and Parkinson''s disease. In this study, we examined the neurotoxicity of an organochlorine pesticide, heptachlor, in vitro and in vivo. In cultured SH-SY5Y cells, heptachlor induced mitochondria-mediated apoptosis. When injected into mice intraperitoneally on a subchronic schedule, heptachlor induced selective loss of dopaminergic neurons in the substantia nigra pars compacta. In addition, the heptachlor injection induced gliosis of microglia and astrocytes selectively in the ventral midbrain area. When the general locomotor activities were monitored by open field test, the heptachlor injection did not induce any gross motor dysfunction. However, the compound induced Parkinsonism-like movement deficits when assessed by a gait and a pole test. These results suggest that heptachlor can induce Parkinson''s disease-related neurotoxicities in vivo.  相似文献   
975.
976.
This work shows that a hollow and microporous metal-free N,N′-phenylenebis(salicylideneimine) (salphen) network (H-MSN) can be engineered by Sonogashira coupling of [tetraiodo{di(Zn-salphen)}] building blocks with 1,4-diethynylbenzene in the presence of silica templates and by successive Zn and silica etching. Iron(III) ions could be incorporated into the H-MSN to form hollow and microporous Fe–disalphen networks (H-MFeSN) with enhanced microporosity and surface area. The H-MFeSN showed efficient catalytic performance and recyclability in the CO2 conversion to cyclic carbonates.  相似文献   
977.
Gold nanorod‐attached PEGylated graphene‐oxide (AuNR‐PEG‐GO) nanocomposites were tested for a photothermal platform both in vitro and in vivo. Cytotoxicity of AuNR was reduced after encapsulation with PEG‐GO along with the removal of cetyltrimethylammonium bromide (CTAB) from AuNR by HCl treatment. Cellular internalization of the CTAB‐eliminated AuNR‐PEG‐GO nanocomposites was examined using dark‐field microscopy (DFM), confocal Raman microscopy and transmission electron microscopy (TEM). To determine the photothermal effect of the AuNR‐PEG‐GO nanocomposites, A431 epidermoid carcinoma cells were irradiated with Xe‐lamp light (60 W cm?2) for 5 min after treatment with the AuNR‐PEG‐GO nanocomposites for 24 h. Cell viability significantly decreased by ~40% when the AuNR‐PEG‐GO‐encapsulated nanocomposites were irradiated with light as compared with the cells treated with only the AuNR‐PEG‐GO nanocomposites without any illumination. In vivo tumor experiments also indicated that HCl‐treated AuNR‐PEG‐GO nanocomposites might efficiently reduce tumor volumes via photothermal processes. Our graphene and AuNR nanocomposites will be useful for an effective photothermal therapy.  相似文献   
978.
979.
980.
We report a poly(ethylene glycol)‐poly(L ‐alanine)‐azobenzene‐poly(L ‐alanine)‐poly(ethylene glycol) (PEG‐PA‐Z‐PA‐PEG) as a temperature and light sensitive polymer. The poly(ethylene glycol)‐poly(L ‐alanine) diblock copolymers with a flexible‐rigid block structure were coupled by an azobenzene group that undergoes a reversible configurational change between “trans” and “cis” upon exposure to UV and vis light. The single azobenzene molecule embedded in the middle of a block copolymer with a flexible (shell)‐rigid (core) structure significantly affected molecular assembly, micelle size, polypeptide secondary structure, and sol‐to‐gel transition temperature of the polymer aqueous solution, depending on its exposure to UV or vis light. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012  相似文献   
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