共查询到20条相似文献，搜索用时 97 毫秒
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利用熔融淬冷法制备了GeS2-Ga2S3-CdBr2体系硫卤玻璃,确定了它的玻璃形成区。利用x-射线衍射谱、拉曼光谱、综合热分析、紫外-可见-近红外透射光谱和红外吸收光谱等技术深入研究了GeS2-Ga2S3-CdBr2三元系玻璃的形成、结构与性能的关系。实验结果表明：GeS2-Ga2S3-CdBr2体系的玻璃转变温度在550K-700K之间,玻璃的△T值较高,H’值可达0.3。玻璃的红外截止边均在11μm左右,紫外截止边均在430-470nm范围内。通过对该玻璃体系的系统研究表明它是中红外光学器件的理想候选材料。 相似文献
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聚醚酰亚胺（PEI）是在聚酰亚胺链上引入醚键而形成的一类高聚物,通过设计的四步法进行了PIE聚合所需单体双酚A型二醚二酐（BPDEDA）的合成,并运用哈克转矩流变仪进行BPDEDA与间苯二胺的熔融聚合,所得PEI树脂与美国GE公司的Ultem4000树脂在红外光谱、13C核磁共振、DSC、TG图谱的比较上具有较好的一致性. 相似文献
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研究第三方网上支付理论的基础上,对三种典型的电子商务B2B、B2C、C2C的第三方网上支付进行了比较分析,总结了基于B2B、B2C、C2C的第三方网上支付系统模式及其存在的问题,最后规划了第三方协同网上支付的构建模式及其特性。 相似文献
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1临床资料 病例1,患者42岁,藏族,男性。因“怕冷2年,全身浮肿1年”入院。2年前无任何原因出现怕冷,且易疲乏,未曾引起患者重视。1年前出现浮肿,当时伴双侧腰部阵发性胀痛及恶心、呕吐,尿量少,曾到藏医院就诊,诊断为慢性肾炎、胆囊结石,予珍珠七十、青霉素、排石饮液等药物 相似文献
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吴英毅 《中国科学院研究生院学报》2008,25(5):585-591
HCMU是一种在Riemann面上带奇点的extremal度量．在面积和Calabi能量有界的情况下, HCMU的Gauss曲率是Riemann面上的连续函数．本文得到一个在球面上没有Gauss曲率鞍点的HCMU的明显表达式,并进一步证明了在球面或环面上HCMU的Gauss曲率光滑的充要条件是度量的所有奇点的角度都是整数． 相似文献
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Zhengwei Zhang Peng Chen Xiangdong Yang Yuan Liu Huifang Ma Jia Li Bei Zhao Jun Luo Xidong Duan Xiangfeng Duan 《国家科学评论(英文版)》2020,7(4):737
Monolayer transition metal dichalcogenides (TMDs) have attracted considerable attention as atomically thin semiconductors for the ultimate transistor scaling. For practical applications in integrated electronics, large monolayer single crystals are essential for ensuring consistent electronic properties and high device yield. The TMDs available today are generally obtained by mechanical exfoliation or chemical vapor deposition (CVD) growth, but are often of mixed layer thickness, limited single crystal domain size or have very slow growth rate. Scalable and rapid growth of large single crystals of monolayer TMDs requires maximization of lateral growth rate while completely suppressing the vertical growth, which represents a fundamental synthetic challenge and has motivated considerable efforts. Herein we report a modified CVD approach with controllable reverse flow for rapid growth of large domain single crystals of monolayer TMDs. With the use of reverse flow to precisely control the chemical vapor supply in the thermal CVD process, we can effectively prevent undesired nucleation before reaching optimum growth temperature and enable rapid nucleation and growth of monolayer TMD single crystals at a high temperature that is difficult to attain with use of a typical thermal CVD process. We show that monolayer single crystals of 450 μm lateral size can be prepared in 10 s, with the highest lateral growth rate up to 45 μm/s. Electronic characterization shows that the resulting monolayer WSe2 material exhibits excellent electronic properties with carrier mobility up to 90 cm2 V−1 s−1, comparable to that of the best exfoliated monolayers. Our study provides a robust pathway for rapid growth of high-quality TMD single crystals. 相似文献
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本文分析了基于现有DEA有效输出定义的DEA有效输出方法存在的不足，在此基础上提出了新的DEA有效输出的定义，并得到了预测DEA有效输出区间的方法。 相似文献
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利用分子动力学模拟方法,发现不同孔径的钻孔石墨烯对氢气和氮气有很好的分离性.当挖去了10个碳原子,孔径为0.3725 nm时,分离效率可以达到100%.由结果可以预见,钻孔石墨烯将会在气体分离和纯化方面有应用潜力. 相似文献
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SONG Jianlan 《中国科学院院刊(英文版)》2013,27(1):16-18
Ensuing previous breakthroughs in the field of iron-based superconductivity achieved by their colleagues at the Institute of Physics and the Beijing National Laboratory for Condensed Matter Physics under CAS, a group of physicists led by Prof. ZHENG Guoqing recently obtained unambiguous evidence for a microscopic coexistence of antiferromagnetic order and superconductivity in a 相似文献
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