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以柠檬酸、乙二胺和乙酸锌为前体,采用一步水热法制备了一种稳定的、高荧光量子产率的水溶性锌掺杂碳量子点(Zn-CQDs)。通过透射电子显微镜(TEM)、X射线衍射(XRD)、傅立叶红外光谱(FTIR)、紫外-可见吸收光谱(UV-Vis)、荧光光谱对Zn-CQDs的结构和光学性能进行了表征。研究表明,Cu~(2+)对Zn-CQDs的荧光产生猝灭,体系的荧光信号处于"关闭"状态,还原型谷胱甘肽(GSH)的存在,使Zn-CQDs-Cu~(2+)体系的荧光得以恢复,体系的荧光信号处于"打开"状态。由此构建了"关-开"型荧光探针用于谷胱甘肽(GSH)的选择性、高灵敏检测。探究了反应p H值和反应时间对荧光恢复体系的影响,同时考察了果蔬中常见的有机小分子和离子对Zn-CQDs-Cu~(2+)体系荧光强度的影响,在最佳实验条件下,GSH浓度在0. 05~80μmol/L内与Zn-CQDs荧光恢复率呈线性关系,检出限达63 nmol/L。将该探针用于果蔬中GSH的检测,样品的加标回收率为98. 6%~101%,相对标准偏差为1. 8%~3. 1%,结果令人满意。 相似文献
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A thin radar-infrared stealth-compatible structure:Design,fabrication,and characterization 下载免费PDF全文
A thin radar-infrared stealth-compatible structure with reflectivity below -10 dB in the whole radar X wave band and infrared emissivity less than 0.3 in the infrared region of 8μm-14 μm is reported. The designed stealth-compatible structure consists of metallic frequency selective surface (MFSS), resistive frequency selective surface (RFSS), and metal backing from the top down, and it is only 2. l-mm thick. The MFSS is made up of some divided low infrared emissivity metal copper films, and the RFSS consists of a capacitive array of square resistive patches. They are placed close together, working as an admittance sheet because of a mutual influence between them, and the equivalent admittance sheet greatly reduces the thickness of the whole structure. The proposed stealth-compatible structure is verified both by simulations and by experimental results. These results indicate that our proposed stealth-compatible structure has potential applications in stealth fields. 相似文献
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徐敏 何康林 张子平 王贻芳 边渐鸣 曹国富 曹学香 陈申见 邓子艳 傅成栋 高原宁 韩磊 韩少卿 何苗 胡继峰 胡小为 黄彬 黄性涛 贾卢魁 季晓斌 李海波 李卫东 梁羽铁 刘春秀 刘怀民 刘颖 刘勇 罗涛 吕绮雯 马秋梅 马想 冒亚军 毛泽普 莫晓虎 宁飞鹏 平荣刚 邱进发 宋文博 孙胜森 孙晓东 孙永昭 田浩来 王纪科 王亮亮 文硕频 伍灵慧 吴智 谢宇广 言杰 严亮 姚剑 苑长征 袁野 张长春 张建勇 张雷 张学尧 张瑶 郑阳恒 朱永生 邹佳恒 《中国物理 C》2009,33(6):428-435
This paper focuses mainly on the vertex reconstruction of resonance particles with a relatively long lifetime such as Ks^0, A, as well as on lifetime measurements using a 3-dimensional fit. The kinematic constraints between the production and decay vertices and the decay vertex fitting algorithm based on the least squares method are both presented. Reconstruction efficiencies including experimental resolutions are discussed. The results and systematic errors are calculated based on a Monte Carlo simulation. 相似文献
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梁羽铁 刘坤 尤郑昀 冒亚军 李卫东 边渐鸣 曹国富 曹学香 陈申见 邓子艳 傅成栋 高原宁 韩磊 韩少卿 何康林 何苗 胡继峰 胡小为 黄彬 黄性涛 贾卢魁 季晓斌 李海波 刘北江 刘春秀 刘怀民 刘颖 刘勇 罗涛 吕绮雯 马秋梅 马想 毛泽普 莫晓虎 宁飞鹏 平荣刚 邱进发 宋文博 孙胜森 孙晓东 孙永昭 田浩来 王纪科 王亮亮 文硕频 伍灵慧 吴智 谢宇广 徐敏 言杰 严亮 姚剑 苑长征 袁野 张长春 张建勇 张雷 张学尧 张瑶 郑阳恒 朱永生 邹佳恒 《中国物理 C》2009,33(8):666-672
The reconstruction algorithm for BESⅢ Muon Counter, MucRecAlg, is developed with the objectoriented language C++ in BESⅢ offine software environment. MucRecAlg consists of the following functions:to find track seeds either from extrapolation of tracks in the main drift chamber or from the fired strips in muon counter, to select fired strips associated to the candidate tracks, to fit the candidate tracks with a linear or quadratic function and to calculate other parameters of the tracks for muon identification. Monte Carlo samples are generated to check the performance of the reconstruction package, such as reconstruction effciency, muon remaining rate and pion rejection rate, etc. The preliminary results show that the pion rejection rate is around 3%—4% while the muon remaining rate is better than 90% in 0.4—1.6 GeV/c momentum region, which meets the requirement as shown in the design report. 相似文献
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The total dose radiation response of pseudo-MOS transistors fabricated in hardened and unhardened FD (fully-depleted) SIMOX (Separation by Implanted Oxygen) SOI (Silicon-on-insulator) wafers is presented. At 1 Mrad(Si) radiation dose, the threshold voltage shift of the pseudo-MOS transistor is reduced from -115.5 to -1.9 V by the hardening procedure. The centroid location of the net positive charge trapped in BOX, the hole-trap density and the hole capture fraction of BOX are also shown. The results suggest that hardened FD SIMOX SOI wafers can perform well in a radiation environment. 相似文献
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弹性连接旋转柔性梁动力学分析 总被引:2,自引:0,他引:2
采用Chebyshev 谱方法对考虑根部连接弹性的平面内旋转柔性梁动力学特性进行研究. 基于Gauss-Lobatto 节点与Chebyshev 多项式方法对柔性梁变形场进行离散,通过投影矩阵法施加固定及弹性连接边界条件. 利用Chebyshev 谱方法获得了系统固有频率和模态振型数值解,通过与有限元方法及加权残余法的比较,验证了方法的有效性. 分析了弹性连接刚度、角速度比率、系统径长比及梁的长细比等参数对系统固有频率及模态振型的影响. 研究发现:由于系统弯曲模态、拉伸模态的频率随各参数的变化规律不一致,将出现频率转向与振型转换现象;随着弹性连接刚度、角速度比率及系统径长比的增大,低阶弯曲模态频率增大并超过高阶拉伸模态频率,随着梁的长细比的增大,低阶拉伸模态频率增大并超过高阶弯曲模态频率. 相似文献
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言杰 孙胜森 李澄 何康林 安琪 边渐鸣 曹国富 曹学香 陈宏芳 邓子艳 封常青 傅成栋 何苗 衡月昆 黄彬 郭建华 贾卢魁 季晓斌 李卫东 梁羽铁 刘春秀 刘怀民 刘树彬 刘曙东 刘勇 罗涛 马秋梅 马想 毛泽普 莫晓虎 邱进发 邵明 孙晓东 孙勇杰 孙永昭 孙志嘉 田浩来 王纪科 文硕频 吴金杰 伍灵慧 吴智 谢宇广 徐敏 严亮 杨桂安 袁野 张长春 张建勇 张瑶 赵川 赵雷 朱永生 邹佳恒 《中国物理 C》2010,34(3):368-373
The principle of the method for the BESIII TOF calibration using cosmic ray data without magnetic field are reported in this paper. After applying calibration constants, the single-end readout time resolution could reach about 150 ps, and the time resolution for one layer is achieved to be about 110 ps. The paper also described the extraction scheme for the event start time of cosmic events. 相似文献
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贾卢魁 毛泽普 李卫东 曹国富 曹学香 邓子艳 何康林 刘春燕 刘怀民 刘秋光 马秋梅 马想 邱进发 田浩来 王纪科 伍灵慧 袁野 臧石磊 张长春 张雷 张瑶 朱凯 邹佳恒 《中国物理 C》2010,34(12):1866-1873
In order to overcome the difficulty brought by the circling charged tracks with transverse momentum less than 120 MeV in the BESⅢ Main Drift Chamber (MDC), a specialized method called TCurlFinder was developed. This tracking method focuses on the charged track reconstruction under 120 MeV and possesses a special mechanism to reject background noise hits. The performance of the package has been carefully checked and tuned by both Monte Carlo data and real data. The study shows that this tracking method could obviously enhance the reconstruction efficiency in the low transverse momentum region, providing physics analysis with more and reliable data. 相似文献
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设计了一套以R134a为冷媒的微槽道两相流循环散热系统,用于冷却高发热密度的服务器CPU,实测综合传热系数1000~1200 W/(m^2·℃)。冷却水既可以由制冷机提供,也可以由蒸发冷却装置提供.搭建了实验测试平台,系统地测试和对比了该系统在不同CPU负荷和冷却水供水温度工况下的散热性能.测试结果表明,通过饱和温度为25~30℃的R134a两相流相变传热,可将散热热流密度为3 W/cm^2量级、总散热量在50~150 W量级的CPU本体温度稳定控制在50~60℃。根据实测数据,在不同气候条件下,该系统应用于大型数据中心全年理论能效比可以达到10以上,远高于常规机房空调。该系统具有换热能力强、体积小、能效高、冷源温度高、适用性广、节能潜力大等优点,具有可观的经济效益和社会效益。 相似文献