稳定同位素标记化合物二氢吡啶-13C4的合成与表征

本文以同位素标记的乙酰乙酸乙酯-1,3-13C2为原料,经Hantzsch多组分缩合反应合成得到稳定性同位素标记的化合物二氢吡啶-13C4 (二乙基-1,4-二氢-2,6-二甲基-3,5-吡啶二羧酸酯-13C4),该化合物为新化合物,其结构经1HNMR、13CNMR和MS（ESI）表征。结果表明,所合成的目标产品,化学纯度大于99.0%,13C丰度为99.4% (atom 13C)。该化合物可作为食品安全领域检测用同位素内标试剂,具有重要的应用价值。     

Using well-plate microfluidic devices to conduct shear-based thrombosis assays

Shear stress plays a critical role in regulating platelet adhesion and thrombus formation at the site of vascular injury. As such, platelets are often examined in vitro under controlled shear flow conditions for their hemostatic and thrombotic functions. Common shear-based platelet analyses include the evaluation of genetic mutants, inhibitory or experimental compounds, matrix substrates, and the effects of different physiological and pathological shear forces. There are several laboratory instruments widely used for studying shear flow, including cone and plate viscometers and parallel plate perfusion chambers. These technologies vary widely in the types of samples, substrates, blood volumes, and throughput that are involved. Here, we describe a microfluidic system for platelet analysis under shear flow. We used the devices to study thrombus formation on collagen I and von Willebrand factor. The system was also used to investigate dose response to the antiplatelet compound, Abciximab, under shear flow conditions with an emphasis on maximizing the number of data points per single patient sample. The presented method confers multiple advantages over conventional approaches. These include the ability to assess up to 24 conditions simultaneously in real time, maintain identical physical conditions across experiments, and use extremely low donor volumes.     

氧气传感760 nm垂直腔面发射半导体激光器

在国内首次报道了氧气传感专用760 nm单模、波长可调谐的垂直腔面发射激光器 （Vertical Cavity Surface-Emitting Laser, VCSEL）,详细报道了760 nm VCSEL设计方法与器件制备结果。通过分析AlGaAs量子阱的增益特性,确定了量子阱组分及厚度参数,并设计了室温下增益峰与腔模失配为10 nm的VCSEL激光器结构,完成了VCSEL结构的器件制备。VCSEL激光器在工作温度25 °C时单模功率超过2 mW ,此时边模抑制比为28.1 dB,发散角全角为18.6°。随着工作电流增加,VCSEL激光器的发散角随之增加,然而激光远场光斑仍然为高斯形貌的圆形对称光斑。通过调节VCSEL激光器的工作温度与工作电流,实现了VCSEL单模激光波长从758.740 nm至764.200 nm的近线性连续调谐,VCSEL工作在15 ~ 35 °C时激光波长的电流调谐系数由1.120 nm/mA变至1.192 nm/mA; 温度调谐系数由0.072 nm/°C变至0.077 nm/°C。在两个氧气特征吸收波长附近,VCSEL激光的边模抑制比分别达到了32.6 dB与30.4 dB。     

A Unified Co-Processor Architecture for Matrix Decomposition

QR and LU decompositions are the most important matrix decomposition algorithms. Many studies work on accelerating these algorithms by FPGA or ASIC in a case by case style. In this paper, we propose a unified framework for the matrix decomposition algorithms, combining three QR decomposition algorithms and LU algorithm with pivoting into a unified linear array structure. The QR and LU decomposition algorithms exhibit the same two-level loop structure and the same data dependency. Utilizing the similarities in loop structure and data dependency of matrix decomposition, we unify a fine-grained algorithm for all four matrix decomposition algorithms. Furthermore, we present a unified co-processor structure with a scalable linear array of processing elements (PEs), in which four types of PEs are same in the structure of memory channels and PE connections, but the only difference exists in the internal structure of data path. Our unified co-processor, which is IEEE 32-bit floating-point precision, is implemented and mapped onto a Xilinx Virtex5 FPGA chip. Experimental results show that our co-processors can achieve speedup of 2.3 to 14.9 factors compared to a Pentium Dual CPU with double SSE threads.     

Analysis of the resequencing buffer in a homogeneous M/M/2 queue

The resequencing problem is encountered in many practical information systems such as distributed database and communication networks. In these systems customers, such as messages in a computer network, have to be delivered to users in their original order. Therefore, those customers which become out of order due to the randomness of the system are forced to wait in a resequencing buffer so that their delivered order can be guaranteed. The previous work on the resequencing problem mainly concentrated on the delay aspect. From both theoretical and practical viewpoints, however, the queue length characteristics of the resequencing buffer are also significant. We consider the queue length distribution of the resequencing buffer fed by a homogeneous M/M/2 queue. The exact analysis is carried out for the probability mass functions of the queue length in equilibrium and the maximal occupancy which corresponds to the queue length just before the departure instants of customers from the resequencing buffer.     

Structural, photophysical and photocatalytic properties of Bi2MTaO7 (M = La and Y)

Bi₂MTaO₇ (M = Y and La) were synthesized by solid-state reaction method and their structural and photocatalytic properties were investigated. The results indicated that these compounds crystallize in the pyrochlore-type structure, cubic system with space group Fd-3 m. In addition, the band gaps of Bi₂LaTaO₇ and Bi₂YTaO₇ were estimated to be about 2.17(3) and 2.22(7) eV, respectively. For the photocatalytic water splitting reaction, H₂ or O₂ evolution was observed from pure water respectively with Bi₂MTaO₇ (M = Y and La) as the photocatalysts under ultraviolet light irradiation. Photocatalytic degradation of aqueous methylene blue (MB) dye over these compounds was further investigated under visible light irradiation. Bi₂MTaO₇ (M = Y and La) showed markedly higher catalytic activity compared to P-25 for MB photocatalytic degradation under visible light irradiation. Complete removal of aqueous MB was observed after visible light irradiation for 190 min with Bi₂LaTaO₇ as the photocatalyst and for 200 min with Bi₂YTaO₇ as the photocatalyst. The decrease of the total organic carbon (TOC) and the formation of inorganic products, SO₄²⁻ and NO₃⁻, demonstrated the continuous mineralization of aqueous MB during the photocatalytic process.     

基于Raspberry Pi的家庭健康监测网关

随着人口老龄化和亚健康人群的增多,人们对健康监测服务的需求也不断增加.心率、血压、血糖等生理数据中包含了人体健康状况的重要病理信息,为接收和预处理这些生理数据,并完成对生理检测设备的集中管理和数据的自动采集,本文基于Raspberry Pi （树莓派）研究开发了一个家庭健康监测网关.该家庭健康监测网关,通过蓝牙通讯获取生理检测设备的数据,并进行存储或利用无线网络将其传输至服务器.最后,以监护对象的心电数据采集、传输及展示过程为例,对系统整体进行功能性测试.该网关为家庭健康监测提供了可行的方案,在减轻社会医疗压力方面具有重要意义.     

Optical,structural and photophysical properties of Ga2BiTaO7 compound

The Ga₂BiTaO₇ compound was synthesized by solid-state reaction method and characterized by powder X-ray diffraction method and the Rietveld structure refinement. This compound crystallizes in the pyrochlore-type structure, cubic system with space group Fd3m and the lattice parameter a = 10.4544(2) Angstrom. The band gap of the Ga₂BiTaO₇ compound was estimated to be about 2.47(1) eV. It shows strong optical absorption in the visible light region (λ > 420 nm). This indicates that the Ga₂BiTaO₇ compound has the ability to respond to wavelength of visible light region and has potential for splitting water into H₂ and O₂ under visible light irradiation. Photocatalytic degradation of methylene blue (MB) dye on the Ga₂BiTaO₇ compound was first investigated under ultraviolet light and visible light irradiation. MB was obviously degraded after visible light irradiation for 140 min with the photocatalyst at room temperature in air. The high activity has potential to be kept in a wide range of wavelength up to 505 nm.