Tracking a Screen and Detecting Its Rate of Change in 3-D Video Scenes of Multipurpose Halls

An automatic approach is presented to track a wide screen in a multipurpose hall video scene. Once the screen is located, this system also generates the temporal rate of change by using the edge detection based method. Our approach adopts a scene segmentation algorithm that explores visual features （texture） and depth information to perform efficient screen localization. The cropped region which refers to the wide screen undergoes salient visual cues extraction to retrieve the emphasized changes required in rate-of- change computation. In addition to video document indexing and retrieval, this work can improve the machine vision capability in the behavior analysis and pattern recognition.

Lorentz Force from a Current-Carrying Wire on a Charge in Motion under the Assumption of Neutrality in the Symmetrical Frame of Reference

It is commonly assumed that a wire conducting an electric current is neutral in the laboratory frame of reference (the rest frame of the lattice of positive ions). Some authors consider that the wire is neutral only in a symmetrical frame of reference, in which the velocities of electrons and protons have equal norm and opposite direction. In this paper, we discuss the Lorentz transformation between different frames of reference in the context of the special theory of relativity for a current-carrying conducting wire and a probe charge in motion with respect to the wire. A simple derivation of the Lorentz force in the laboratory frame of reference for the assumed neutrality in a symmetrical frame of reference is presented. We show that the Lorentz force calculated assuming neutrality in the symmetrical frame of reference and the one assuming neutrality in the laboratory frame of reference differ by a term corresponding to a change in the test charge speed of one half the drift velocity of the electrons.

不同茶树品种中黄酮苷含量的测定

本研究采用液相质谱技术分离、鉴定了茶叶中的12种黄酮苷类化合物,包括1种芹菜素苷、2种杨梅素苷、5种槲皮素苷和4种山奈酚苷。结合标准品及高效液相色谱系统,测定了8种不同茶树品种中黄酮苷类化合物的含量。结果显示,不同茶树品种中黄酮苷含量分布广泛,以槲皮苷为主。紫芽品种中12种黄酮苷含量最高,达6.12 mg/g;福建水仙品种中含量最低,仅2.31 mg/g,茶树品种间存在显著性差异(P<0.05)。

电化学法快速测定茶多酚含量的研究

基于电化学循环伏安法,讨论了3种低成本自制工作电极——银电极、碳糊电极和玻碳电极在茶多酚含量测定应用上的可行性。通过分析茶多酚在电极表面的氧化还原行为,发现所制银电极不适宜检测茶多酚,碳糊电极、玻碳电极的氧化电流峰值与茶多酚含量有良好的线性关系。所制玻碳电极测定绿茶茶样中的茶多酚含量的重复性和准确性较碳糊电极好。与国标方法相比,碳糊电极、玻碳电极检测茶多酚所需时间大大缩短。结果表明,电化学方法可应用于茶多酚含量的快速测定,从而为快速、低价、便捷检测茶多酚提供一条新思路。

新型3-CPS/RPPS机构的有限元建模及模态分析

对新型3-CPS/RPPS型六自由度机构进行有限元建模和模态分析,系统介绍了采用有限元法进行多自由度机构建模和进行模态分析的过程。介绍了新型3-CPS/RPPS机构的机构原理;探讨了采用有限元法进行多自由度机构相关机构分析的可行性;详细介绍了采用基于静凝聚理论的自由度释放法建立多自由度机构铰链的过程,并修改开源有限元程序CALFEM的3维梁单元实现了铰链的功能;基于MATLAB和CALFEM,对3-CPS/RPPS机构进行简化,建立了基于三维梁单元的有限元模型,进行了模态分析,给出了最低8阶固有频率和前4阶振型。最后探讨了有限元法在多自由度机构或并联机器人机构分析领域的应用前景。

Antibiotic-Loaded Resorbable Bone-Graft Substitute： A New Treatment for Osteomyelitis/Osteitis

Patients with osteomyelitis require lengthy antibiotic treatment, often only to see the inflammation flare up once antibiotics are suspended. Unfortunately, patients often discontinue the antibiotic treatment due to collateral effects. Patients with osteitis are often polymorbid patients with other severe diseases such as diabetes mellitus and polyneuropathy, arteriopathy or polyarthfitis with immunosuppression. The eight patients included in the study presented nine bones with osteomyelitis （macroscopically, bacteriologically, histologically or radiologically）. The diseased part of the bone was resected, a locally radical debridement was done and a biopsy for bacteriology and histology were taken. The residual bone was then drilled out and filled with antibiotic-loaded （gentamicin） resorbable bone-graft substitute under radiologic imaging control. In total, seven patients are currently without recurrent osteomyelitis with a mean follow-up of 5.77 months （2-11 months）. The Kaplan Meier curve shows 80% survival rate without recurrent osteomyelitis at 11 months. Only one patient suffering from Morbus Buerger had a relapse osteomyelitis after cutting off severing his foot while swimming in the sea. Antibiotic-loaded resorbable bone-graft substitute is easy to use, has in our hands few complications and low recurrence rate.

Characteristics of different charge transfer modes in upward flashes inferred from simultaneously measured currents and fields

The authors present an analysis of different charge transfer modes during upward negative flashes.The analysis includes a total number of 94 pulses that occurred during two upward negative flashes recorded at the Säntis Tower.The pulses included 59 mixed-mode(MM)initial continuous current(ICC)pulses,17 M-component-type ICC(M-ICC)pulses,8 returnstroke pulses,and 10 classical M-component(MC)pulses.It is found that the initial stage of the flash is responsible for the largest share of the total charge transferred to the ground.Simulation results for the electric fields associated with the considered charge transfer modes are presented and discussed.Return stroke(RS)and MM pulses were simulated adopting the MTLE model,while MCs and M-ICC pulses were simulated using the guided wave model of Rakov et al.The simulated results are shown to be in good agreement with simultaneous records of electric fields measured at a distance of 15 km from the Säntis Tower.The inferred velocities for MCs and M-ICC pulses range from 2.0×10^(7) to 9.0×10^(7) m/s,and the corresponding junction point heights range from 1.0 to 2.0 km.The inferred pulse velocities for RSs and MM pulses range from 1.3×10^(8) to 1.65×10^(8) m/s.The inferred current attenuation constants of the MTLE model obtained in this study range from 0.3 to 0.8 km,lower than the value of 2 km previously suggested for RSs in downward flashes.The obtained results support the assumption that the mode of charge transfer to the ground giving rise to MM pulses is similar to that of RSs.The results are also in support of the generally assumed similarity between M-ICC pulses and classical MCs.

A miniaturized system for measurement of the refractive index of sub-microliter liquid

This study introduced the research and development of a portable and miniaturized system for the measurement of the refractive index of sub-microliter liquid based on a microfluidic chip. A technical method of double-beam interference, was proposed for use in the measurement. Based on this, by using a laser diode as a light source,changes in the refractive index were calculated by utilizing a complementary metal–oxide–semiconductor to detect the movement of interference fringes of the liquid. Firstly, this study simulated the effects of influencing factors on the interference infringes of two Gaussian beams, such as their spot sizes, distance between two beam spots, and detection range. Secondly, this research introduced the system design and construction of the doublebeam interference method and analyzed the results of refractive index tests on sub-microliter aqueous glucose solutions with different concentrations. The measurement accuracy reached 10^(-4) refractive index units. This system has a compact structure and is rendered portable by using batteries for its power supply. The entire system is designed to be a double Z-shaped structure with a length of about 15 cm, a width of 5 cm, and a height of about 10 cm. It can be used to measure changes in the refractive index of sub-microliter to nanoliter liquids based on the use of a microfluidic chip.

Bayesian bootstrap quantile regression for probabilistic photovoltaic power forecasting

Photovoltaic(PV)systems are widely spread across MV and LV distribution systems and the penetration of PV generation is solidly growing.Because of the uncertain nature of the solar energy resource,PV power forecasting models are crucial in any energy management system for smart distribution networks.Although point forecasts can suit many scopes,probabilistic forecasts add further flexibility to an energy management system and are recommended to enable a wider range of decision making and optimization strategies.This paper proposes methodology towards probabilistic PV power forecasting based on a Bayesian bootstrap quantile regression model,in which a Bayesian bootstrap is applied to estimate the parameters of a quantile regression model.A novel procedure is presented to optimize the extraction of the predictive quantiles from the bootstrapped estimation of the related coefficients,raising the predictive ability of the final forecasts.Numerical experiments based on actual data quantify an enhancement of the performance of up to 2.2%when compared to relevant benchmarks.