Dynamical analysis,circuit realization,and application in pseudorandom number generators of a fractional-order laser chaotic system

A new five-dimensional fractional-order laser chaotic system (FOLCS) is constructed by incorporating complex variables and fractional calculus into a Lorentz-Haken-type laser system. Dynamical behavior of the system, circuit realization and application in pseudorandom number generators are studied. Many types of multi-stable states are discovered in the system. Interestingly, there are two types of state transition phenomena in the system, one is the chaotic state degenerates to a periodical state, and the other is the intermittent chaotic oscillation. In addition, the complexity of the system when two parameters change simultaneously is measured by the spectral entropy algorithm. Moreover, a digital circuit is design and the chaotic oscillation behaviors of the system are verified on this circuit. Finally, a pseudo-random sequence generator is designed using the FOLCS, and the statistical characteristics of the generated pseudo-random sequence are tested with the NIST-800-22. This study enriches the research on the dynamics and applications of FOLCS.     

近紫外光激发的单一全发射荧光粉的发光性能(英文)

利用传统的高温固相法合成了2MgO·Al2O3·P2O5掺Eu,Tb3+,Mn2+系列荧光粉,并研究了它们的发光性能。荧光粉2MgO0.95·Al2O3·P2O5∶0.02Eu,0.02Tb,0.01Mn在近紫外光区具有很强的吸收。在近紫外光激发下,样品发射谱中包含明显的红光、绿光、蓝光3种发射。其CIE色度坐标(0.35,0.25)接近白光区域,在近紫外发光二极管方面有潜在的应用前景。     

粉尘质量浓度的光纤光栅传感测量技术

粉尘质量浓度是粉尘爆炸的关键因素，针对目前对本质安全、可实时监测预警的粉尘质量浓度测量技术的迫切需求，提出一种基于光纤光栅和光纤准直器的新型测量技术，在阐述其测量理论的基础上，搭建测量和实验装置实物。对200、300和400目这3种粒径规格的小麦粉尘分别开展实验测量，结果表明:所提出的测量技术的光功率输出和粉尘质量浓度呈线性关系；并与标准的称重法得到的粉尘质量浓度开展对比，验证了光纤光栅测量技术的有效性。     

Welding-packaged accelerometer based on metal-coated FBG

A fiber Bragg grating-based accelerometer with a fully metalized package is presented. Magnetron sputtering and electroplating techneques are successively adopted to metalize bare SiO 2 fiber with a single Bragg grating. Laser welding techneque is adopted to fix the metal-coated fiber on the sensor component to obtain a fully metallized package without adhesives. Vibration test results demonstrate that the accelerometer has a flat frequency response over a 1-kHz bandwidth, with a resonance frequency of 3.6 kHz, wide linear measurement range of up to 8 g, and sensitivity of 1.7 pm/g .     

EFPI-FBG hybrid sensor for simultaneous measurement of high temperature and large strain

We report an extrinsic Fabry–Perot interferometer-fiber Bragg grating(EFPI-FBG) hybrid sensor in this letter. The interferometric cavity of the proposed hybrid sensor is composed of a glass capillary tube, a section of single-mode fiber, and a section of single-mode metal fiber with one FBG. The FBG processed by high-temperature annealing is used to measure temperature, whereas the fiber EFPI is adopted for strain measurement. One of the two aligned fibers is free along the axial direction, which is different from the traditional structure that both the fibers are fixed to glass capillary tube. Experimental results show that the sensor can measure high temperature and large strain simultaneously. The measuring range of temperature and strain for the hybrid sensor is up to 500 °C and 10,000 με, respectively. Effective temperature compensation of the hybrid sensor is realized, too.     

Hybrid fiber Bragg grating sensor for vibration and temperature monitoring of a train bearing

We report a fiber Bragg grating(FBG)-based sensor for the simultaneous measurement of a train bearing's vibration and temperature. A pre-stretched optical fiber with an FBG and a mass is designed for axial vibration sensing. Another multiplexed FBG is embedded in a selected copper-based alloy with a high thermal expansion to detect temperature. Experiments show that the sensor possesses a high resonant frequency of 970 Hz, an acceleration sensitivity of 27.28 pm/g, and a high temperature sensitivity of 35.165 pm/℃. A resonant excitation test is also carried out that demonstrates the robustness and reliability of the sensor.     

聚乙二醇相转移催化作用下Darzens酯缩合

环氧酸酯缩合作用通常在无水条件下进行^[1],不能在应用氢氧化钠水溶液的相转移催化条件下进行。因为卤代酸酯在此情况下发生水解。M.Makosza在无水碳酸钾和18-冠醚-6的两相体系中合成了2-苯基环氧酸乙酯,b.p.99-109℃/0.5mmHg产率72%^[2]。     

超细ZnFe2O4纳米晶与蛋白质的相互作用

水热法制备了超细ZnFe₂O₄纳米晶,并通过高分辨透射电镜(HRTEM)、XRD和EDX技术对其进行了表征。以牛血清白蛋白(Bovine Serum Albumin,BSA)和牛血红蛋白(Hemoglobin)为模式蛋白,研究了纳米晶在不同pH条件下对蛋白质分子的吸附及其与ζ电势的关系。通过动态光散射(Dynamic Light Scattering,DLS)和傅立叶变换红外光谱(Fourier Transform Infrared,FTIR)技术分别研究了纳米晶吸附蛋白后流体力学直径的变化以及蛋白质构象的变化。结果表明,ZnFe₂O₄纳米晶对牛血红蛋白的吸附符合静电吸附的规律,而对BSA的吸附则不符合静电吸附的规律。纳米晶吸附牛血红蛋白后主要以单体和三聚体的形式存在,仅存在少量的团聚体,而吸附BSA后完全以团聚体的形式存在。FTIR光谱则显示纳米晶对牛血红蛋白构象的影响大于对BSA构象的影响。在合适的pH条件下,纳米晶对BSA及牛血红蛋白的吸附容量均超过380mg·g^-1,有望应用于蛋白质的高效分离。     

神经保护剂3β,5α,6β-雄甾三醇原料药中3种非对映异构体的分离与含量测定

建立了分离与测定3β,5α,6β-雄甾三醇(YC-6)原料药中3种非对映异构体的气相色谱方法。进行了分离条件的优化及方法学验证。研究结果表明:该方法可对YC-6与各非对映异构体进行分离,专属性良好(分离度≥1.5),精密度高(RSD≤2.0%);YC-6在6.0~30.0 mg/L质量浓度范围内线性关系良好。测定了非对映异构体的响应因子(1.59,1.32和1.41),并采用加校正因子的主成分自身对照内标法以峰面积计算各非对映异构体的含量。该方法操作简便,结果准确,可用于YC-6原料中各非对映异构体的分离及含量测定。     

CoFe_2O_4纳米晶与牛血清白蛋白和牛血红蛋白的相互作用:吸附、纳米晶的团聚及蛋白构象的变化(英文)

水热制备了约10 nm的CoFe2O4纳米晶,通过Zeta电势、动态光散射(Dynamic Light Scattering,DLS)和傅立叶变换红外光谱(FTIR)技术研究了纳米晶与牛血清白蛋白(Bovine Serum Albumin,BSA)和牛血红蛋白(Hemoglobin)的相互作用。纳米晶对BSA和血红蛋白都有很强的吸附,其中对血红蛋白的吸附符合静电吸附的规律,而对BSA的吸附则不符合静电吸附的规律。在pH=5.5和7.0时纳米晶对BSA和血红蛋白的吸附容量分别达到237.9 mg·g-1和256.9 mg·g-1。DLS结果表明蛋白质能够导致纳米晶团聚。吸附BSA或血红蛋白后,纳米晶的DLS粒径由51 nm分别增大到472 nm和114 nm。CoFe2O4纳米晶还导致了蛋白质FTIR谱发生明显变化。BSA和血红蛋白的酰胺I带由于纳米晶的作用分别减少了4 cm-1和6 cm-1。