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991.
为解决光导开关耐受场强的提高问题,研制了2种体结构光导开关,并进行了实验研究。两种开关均由半绝缘GaAs材料制成,一种尺寸为10.0 mm×10.0 mm×0.6 mm,电极位于10.0 mm×10.0 mm面上相对位置,电极直径6 mm;另一种尺寸为15.0 mm×15.0 mm×3.0 mm,8 mm直径电极位于15.0 mm×15.0 mm面上相对位置。测试了第1种开关在不同半高宽脉冲加载电压下的击穿电压,结果表明其最大耐受电压达7.6 kV,击穿电场127 kV/cm。对第2种结构测试了开关在直流加载条件下的暗态伏安特性并进行了触发实验,结果表明在15 kV工作电压下,其放电最大电流超过3.5 kA。 相似文献
992.
为评定光斑环围参量(包括环围功率和环围尺寸)阵列测试法的测量不确定度,给出了环围参量一般形式的定义和连续形式的计算表达式,归纳并比较了阵列测试法下光斑环围参量的3种常用计算方法,即近似环围功率法、准确环围功率法和等效环围尺寸法,给出了零阶近似下环围参量离散形式的计算表达式。根据不确定度传递律,推导了基于等效环围尺寸法的环围参量测量不确定度的一般表达式,讨论了常见简化条件下的环围参量测量不确定度表达式。建立了光斑环围参量计算及其不确定度评定的一套较完整的方法。以强度为高斯分布的光斑为例,得到了简化条件下的环围参量测量不确定度的解析表达式,并用数值模拟法验证了其正确性。 相似文献
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995.
Shi-Kuo Li Chuan-Hao Li Fang-Zhi Huang Yang Wang Yu-Hua Shen An-Jian Xie Qiong Wu 《Journal of nanoparticle research》2011,13(7):2865-2874
Uniform Cu2O hollow spheres fabricated by single-crystalline particles (smaller than 20 nm) are facile synthesized in ethylene glycol
(EG) solution by a simple solvothermal route without using pre-fabricated templates and reductive agents. EG in this protocol
is not only used as a solvent, complexing agent, and reducing agent, but also served as a structure-directing agent for the
formation of hollow structure. By control of reaction conditions, such as reaction time, temperature, and the anions, the
morphology and structure of the hollow spheres can be tuned. A coordination adsorption and oriented attachment and Ostwald
ripening mechanism is proposed for explaining the formation process of hollow Cu2O spheres in EG solution; and importantly, the hollow Cu2O spheres exhibit an excellent property for the electro-catalytic oxidization of ascorbic acid in acetic acid buffer solution.
Moreover, the hollow spherical Cu2O particles could be potentially applied in catalysis, sensor, and as model for fundamental research. 相似文献
996.
Xinyue Dai Yujie Xie Wei Feng Yu Chen 《Angewandte Chemie (International ed. in English)》2023,62(50):e202309160
Reactive X species (RXS), encompassing elements such as O, N, C, S, Se, Cl, Br, I, and H, play vital roles in cell biology and physiological function, impacting cellular signal transduction, metabolic regulation, and disease processes. The redox unbalance of RXS is firmly implicated in an assortment of physiological and pathological disorders, including cancer, diabetes, cardiovascular disease, and neurodegenerative diseases. However, the intricate nature and multifactorial dependence of RXS pose challenges in comprehending and precisely modulating their biological behavior. Nanomaterials with distinct characteristics and biofunctions offer promising avenues for generating or scavenging RXS to maintain redox homeostasis and advance disease therapy. This minireview provides a tutorial summary of the relevant chemistry and specific mechanisms governing different RXS, focusing on cellular metabolic regulation, stress responses, and the role of nanomedicine in RXS generation and elimination. The challenges associated with chemically regulating RXS for diverse disease treatments are further discussed along with the future prospects, aiming to facilitate the clinical translation of RXS-based nanomedicine and open new avenues for improved therapeutic interventions. 相似文献
997.
High power nano-LiMn2Oa cathode materials with high-rate pulse discharge capability for lithium-ion batteries* 下载免费PDF全文
Nano-LiMn2O4 cathode materials with nano-sized particles are synthesized via a citric acid assisted sol-gel route. The structure, the morphology and the electrochemical properties of the nano-LiMn204 are investigated. Compared with the micro-sized LiMn2O4, the nano-LiMn2O4 possesses a high initial capacity (120 mAh/g) at a discharge rate of 0.2 C (29.6 mA/g). The nano-LiMn2O4 also has a good high-rate discharge capability, retaining 91% of its capacity at a discharge rate of 10 C and 73~ at a discharge rate of 40 C. In particular, the nano-LiMn2O4 shows an excellent high-rate pulse discharge capability. The cut-off voltage at the end of 50-ms pulse discharge with a discharge rate of 80 C is above 3.40 V, and the voltage returns to over 4.10 V after the pulse discharge. These results show that the prepared nano-LiMn2O4 could be a potential cathode material for the power sources with the capability to deliver very high-rate pulse currents. 相似文献
998.
Hua Gong Jian Zhang Ding-Yuan Tang Guo-Qiang Xie Hui Huang Jan Ma 《Journal of nanoparticle research》2011,13(9):3853-3860
Well-dispersed Nd:Y2O3 powders with uniform particle size of about 60 nm were synthesized from freeze-dried precursors. Highly transparent 2 at.%
Nd:YAG ceramics were fabricated from the as-synthesized Nd:Y2O3 powders and commercial Al2O3 powders by vacuum sintering at 1,750 °C for 5 h. Phase evolution, microstructures, and spectroscopic properties of the Nd:YAG
transparent ceramics were investigated. Freeze-drying played an important role in the synthesis of high-quality Nd:Y2O3 nanosized powders, which were essential for the fabrication of highly transparent Nd:YAG ceramics. Optical transmittance
of a 3-mm thick sample reached 82% in the wavelength range of 200–900 nm. 5.23 W output power was obtained with 14.3 W diode
laser pumping, giving a slope efficiency of 36.5%. 相似文献
999.
Lin Su Chao Wang Yong-hao Yu Yong-ying Ren Ke-liang Xie Guo-lin Wang 《BMC neuroscience》2011,12(1):120
Background
Chronic neuropathic pain is an intractable pain with few effective treatments. Moderate cold stimulation can relieve pain, and this may be a novel train of thought for exploring new methods of analgesia. Transient receptor potential melastatin 8 (TRPM8) ion channel has been proposed to be an important molecular sensor for cold. Here we investigate the role of TRPM8 in the mechanism of chronic neuropathic pain using a rat model of chronic constriction injury (CCI) to the sciatic nerve.Results
Mechanical allodynia, cold and thermal hyperalgesia of CCI rats began on the 4th day following surgery and maintained at the peak during the period from the 10th to 14th day after operation. The level of TRPM8 protein in L5 dorsal root ganglion (DRG) ipsilateral to nerve injury was significantly increased on the 4th day after CCI, and reached the peak on the 10th day, and remained elevated on the 14th day following CCI. This time course of the alteration of TRPM8 expression was consistent with that of CCI-induced hyperalgesic response of the operated hind paw. Besides, activation of cold receptor TRPM8 of CCI rats by intrathecal application of menthol resulted in the inhibition of mechanical allodynia and thermal hyperalgesia and the enhancement of cold hyperalgesia. In contrast, downregulation of TRPM8 protein in ipsilateral L5 DRG of CCI rats by intrathecal TRPM8 antisense oligonucleotide attenuated cold hyperalgesia, but it had no effect on CCI-induced mechanical allodynia and thermal hyperalgesia.Conclusions
TRPM8 may play different roles in mechanical allodynia, cold and thermal hyperalgesia that develop after nerve injury, and it is a very promising research direction for the development of new therapies for chronic neuroapthic pain.1000.
Wenyu Ji Letian Zhang Mo Liu Jing Wang Guoqiang Liu Wenfa Xie Hanzhuang Zhang 《Current Applied Physics》2011,11(6):1410-1413
White top-emitting organic light-emitting devices (TEOLEDs) were fabricated on a glass substrate with metal/organic multilayer of (Ag/Alq3)2 (Alq3 is tris-(8-hydroxyquinoline) aluminum) as cathode. White TEOLEDs with high efficiency were obtained due to the microcavity effects. And the (Ag/Alq3)2 cathode, which adjusted the optical characteristics of the devices, played an important role. In addition, Alq3–Ag–Alq3 multilayer could work as a buffer layer, which would simplify the process of encapsulation for devices. We also calculated the electroluminescence spectrum of devices encapsulated with Al2O3 (150 nm) and Al2O3(75 nm)/ZrO2(75 nm). And the results indicated that the CIE coordinates is almost the same between with and without encapsulating. 相似文献