Real Time Anomalous Trajectory Detection and Analysis

GPS-equipped taxis can be considered as pervasive sensors and the large-scale digital traces produced allow us to reveal many hidden facts about the city dynamics and human behaviors. In this paper we present a novel GPS-based taxi system which can detect ongoing anomalous passenger delivery behaviors leveraging our proposed iBOAT method. To achieve real time monitoring, we reduce the response time of iBOAT by more than five times with an inverted index mechanism adopted. We evaluate the effectiveness of the system with large scale real life taxi GPS records while serving 200,000 taxis. With this system, we obtain about 0.44 million anomalous trajectories out of 7.35 million taxi delivery trips, which correspond to 7600 taxis’ GPS records in one month time in the city of Hangzhou, China. Through further analysis of these anomalous trajectories, we observe that: (1) Over 60 % of the anomalous trajectories are “detours” that travel longer distances and time than normal trajectories; (2) The average trip length of drivers with high-detour tendency is 20 % longer than that of normal drivers; (3) The length of anomalous sub-trajectories is usually less than a third of the entire trip, and they tend to begin in the first two thirds of the journey; (4) Although longer distance results in a greater taxi fare, a higher tendency to take anomalous detours does not result in higher monthly revenue; and (5) Taxis with a higher income usually spend less time finding new passengers and deliver them in faster speed.     

Engineering Metal Nanoclusters for Targeted Therapeutics: From Targeting Strategies to Therapeutic Applications

Metal nanoclusters (NCs) have recently attracted great interest in biomedical applications due to their ultrasmall size, good biocompatibility, and unique molecule-like physical and chemical properties. Metal NCs can be rationally designed and integrated with various targeting moieties to achieve unique physicochemical properties and functions. For therapeutic applications, these multifunctional surface-modified NCs can provide distinctive advantages over native metal NCs, such as improved therapeutic effects and reduced side effects. In this review, the design principles of targeting strategies for metal NCs and their composites, including passive and active targeting, and physical and chemical targeting are first discussed. The authors then focus on the recent achievements in the application of metal NCs in targeted therapeutics, including chemotherapy, phototherapy, and radiotherapy. Finally, the authors’ perspectives on the challenges and opportunities of developing metal NCs in targeted therapeutics, further paving their way for potential clinical applications are provided.     

A study on the heat dissipation of high power multi-chip COB LEDs

In this study, the heat dissipation efficiencies of high power multi-chip COB (Chip-on-Board) LEDs with five different chip gaps were compared by assessing their junction temperature (T_j) and thermal resistance (R_th). Junction temperatures were measured using an IR camera and were also simulated by computational fluid dynamics (CFD) software. The effects of heat sinks with different surface areas, heat slugs made of different materials and different injection currents (different wattages) on high power LED junction temperatures are discussed. In addition, the optical characteristics of the LED, such as its lumens and luminous efficiency are evaluated. The experimental results show that a chip with a smaller gap has a higher junction temperature and more thermal resistance, and the junction temperature difference between the LEDs with the smallest and largest chip gaps is 3.12 °C. Optical performance analyses show that the LED with a larger chip gap has higher lumens and higher luminous efficiency. Thus, higher junction temperatures reduce the optical performance of high power LEDs.     

高速光接收机前端的研究

本文从理论上分析了并联电感和串联电感对ＰＩＮ－ＦＥＴ前瑞的作用，证明谐振电感可以有效地抑制ＦＥＴ热噪声的影响，在１．０～１．５ＧＨｚ频率范围内得到接近由量子散粒噪声决定的极限灵敏度。在实验上制作了ＧＨｚ级高速光接收机前端，并用微波网络分析仪测试了前端的频率响应。测试结果与理论分析基本相符。     

镍离子与丙酮、丁酮分子的气相反应

用一种结合激光解离和时间飞行质谱仪的方法去研究金属离子与有机分子的气相反应。研究了金属镍离子与丙酮和丁酮分子的气相反应，并讨论了其反应机理。     

LD端面泵浦Nd：YVO_4激光器及其高阶横模的工作特性

报道了ＬＤ端面泵浦Ｎｄ：ＹＶＯ_４激光器的实验结果，获得了２３．６％的光－光转换效率，相应的斜效率为２８．８％。特别对在泵浦光与腔模匹配欠佳时高阶横模的起振特性作了比较详细的实验研究和定性讨论。     

金属间化合物FeAl超塑性变形中小角度晶界的迁移

利用透射电子显微镜弱束成像技术金属间化合物ＦｅＡｌ超塑性变形后的位错组态，发现一种由「１００」位错和「０１０」位错构成的倾侧小角度晶界，该晶界做了一定的迁移运动而形成一系列台阶，本文讨论了该晶界的台阶形成机制及其对ＦｅＡｌ金属间化合物超塑性变形的贡献。     

Multisim12下的模拟电子线路仿真研究

电压串联负反馈电路在Multisim12进行电路仿真分析,探究了闭环和开环状态下的电压增益、输出阻抗、频率响应和非线性失真等的工作状况,经过Multisim12仿真波形和数据的分析计算,图像清晰,现象直观,结果精确的仿真效果,对电路工作状况研究有一定的借鉴价值.     

Cell Generator: A Self‐Sustaining Biohybrid System Based on Energy Harvesting from Engineered Cardiac Microtissues

Biohybrid soft robotic devices present unique advantages for designing biologically active machines that can dynamically sense and interact with complex bioelectrical signals. Here, a controllable cell‐based machine is developed that harvests energy from arrays of beating cardiomyocytes to generate electricity for biomedical microscale robotic applications. The “Cell Generator” device is based on an array of piezoelectric microcantilevers wrapped with 3D patterned cardiac cells. Spontaneous contraction of the engineered cardiac constructs provides the source of mechanical energy for electricity generation. It is demonstrated that a single “Cell Generator” unit with 40 cantilevers can output peak voltages of ≈70 mV, and a larger array of 540 cantilevers can directly generate a pulsed output as high as ≈1 V. When integrated with an electrical rectification and storage circuit, it is further shown that the “Cell Generator” can provide functional outputs and work as a self‐powered neural stimulator to evoke action potentials in cultured neuronal networks. This demonstration of “Cell Generator” technology provides an innovative perspective of exploiting live biological powering system on biomedical microscale robotic devices in the human body.