景德镇葫芦窑技术源流的考古学观察

葫芦窑是景德镇窑炉技术发展承上启下的重要阶段,梳理葫芦窑的技术源流对厘清景德镇窑炉技术发展的过程有重要意义。以往学界认为景德镇葫芦窑是龙窑与马蹄窑技术结合的产物,但通过分析葫芦窑的结构特征,并将其与龙窑、马蹄窑比较分析,可知景德镇葫芦窑是对景德镇宋元龙窑及其改良技术的继承,并未吸收马蹄窑半倒焰的核心技术。

试析鄱阳湖流域建筑谱系及其源流关系

文章利用历史地理学的方法来探讨区系划分和建筑谱系归类等问题,结果显示出鄱阳湖流域的建筑谱系是多文化混杂的,其中徽派民居与赣、浙匠系有着密切的联系;提出谱系研究除了营造技术层面,也应注重文化层面的特性。同时,文章分析了地理与文化传播等方面的关系,厘出赣系匠作的中心区域。

广东西樵山细石叶石核的开发策略

长期以来,细石叶技术的发展和传播是更新世末期到全新世初期文化传播、人群迁徙和生态适应研究领域探讨的重要课题。20世纪50年代,发现于广东西樵山石器制造场的大批细石叶技术产品,突破了传统意义上对细石叶技术流行、传播范围的认识。早期研究中不少学者就西樵山细石叶制品的形态特征、分布情况进行了介绍,随后鲜见后续研究,缺乏对技术内涵、石核开发策略的深入解析,亦未开展对其所指示的文化传播与人口迁徙问题的探讨。本文选取收藏于中山大学人类学博物馆的343件细石叶石核,通过对石料、毛坯类型、台面类型和数量、剥片面等多方位观察以及对相关技术数值的测量统计,建构西樵山细石叶石核开发策略的模式。这项工作总结了西樵山细石叶技术的特点,并与其他区域的细石叶技术进行对比,加深了对出现在亚热带地区的细石叶技术的认识,为尝试进一步讨论其可能的技术源流和指示人口迁徙与文化传播提供了基础。

A novel technology for control of variable speed pumped storage power plant

Variable speed pumped storage machines are used extensively in wind power plant and pumped storage power plant. This paper presents direct torque and flux control(DTFC) of a variable speed pumped storage power plant(VSPSP). By this method both torque and flux have been applied to control the VSPSP. The comparison between VSPSP's control strategies is studied. At the first, a wind turbine with the capacity 2.2 k W and DTFC control strategies simulated then a 250 MW VSPSP is simulated with all of its parts(including electrical, mechanical, hydraulic and its control system) by MATLAB software. In all of simulations, both converters including two-level voltage source converter(2LVSC) and three-level voltage source converter(3LVSC) are applied. The results of applying 2LVSC and 3LVSC are the rapid dynamic responses with better efficiency, reducing the total harmonic distortion(THD) and ripple of rotor torque and flux.

Application of multivariate statistical techniques in assessment of surface water quality in Second Songhua River basin,China

Multivariate statistical techniques,such as cluster analysis(CA),discriminant analysis(DA),principal component analysis(PCA) and factor analysis(FA),were applied to evaluate and interpret the surface water quality data sets of the Second Songhua River(SSHR) basin in China,obtained during two years(2012-2013) of monitoring of 10 physicochemical parameters at 15 different sites.The results showed that most of physicochemical parameters varied significantly among the sampling sites.Three significant groups,highly polluted(HP),moderately polluted(MP) and less polluted(LP),of sampling sites were obtained through Hierarchical agglomerative CA on the basis of similarity of water quality characteristics.DA identified p H,F,DO,NH3-N,COD and VPhs were the most important parameters contributing to spatial variations of surface water quality.However,DA did not give a considerable data reduction(40% reduction).PCA/FA resulted in three,three and four latent factors explaining 70%,62% and 71% of the total variance in water quality data sets of HP,MP and LP regions,respectively.FA revealed that the SSHR water chemistry was strongly affected by anthropogenic activities(point sources:industrial effluents and wastewater treatment plants;non-point sources:domestic sewage,livestock operations and agricultural activities) and natural processes(seasonal effect,and natural inputs).PCA/FA in the whole basin showed the best results for data reduction because it used only two parameters(about 80% reduction) as the most important parameters to explain 72% of the data variation.Thus,this work illustrated the utility of multivariate statistical techniques for analysis and interpretation of datasets and,in water quality assessment,identification of pollution sources/factors and understanding spatial variations in water quality for effective stream water quality management.

Energy Flows under the Sea--When Nature Inspires Technology

The central idea in this work is to read interconnection between technology and society in the field of the promotion of renewable energies. The challenges of energetic sector are the climate change, the increase of energetic mix and the improvement of a fair access to resources. Future sceneries indicate population＇s needs that must be satisfied with new systems and technologies. For this purpose ocean energies technologies are sure of a good future in the European and world energetic scene. In this work our attention is on the role of tidal currents and sea currents in line with large efforts in RD＆D systems （Research, Development and Demonstration）. We focus our studies about sea turbines with a brief reference to Kobold turbine which is a technology that is moored in the straits of Messina. Technologic innovation depends from several social factors which play an important role in the social construction process of the technology by SCOT approach （social construction of technology）.

Optimal Power Flow Solution Using Particle Swarm Optimization Technique with Global-Local Best Parameters

This paper proposes an efficient method for optimal power flow solution （OPF） using particle swarm optimization （PSO） technique. The objective of the proposed method is to find the steady state operation point in a power system which minimizes the fuel cost, while maintaining an acceptable system performance in terms of limits on generator power, line flow limits and voltage limits. In order to improvise the performance of the conventional PSO （cPSO）, the fine tuning parameters- the inertia weight and acceleration coefficients are formulated in terms of global-local best values of the objective function. These global-local best inertia weight （GLBestlW） and global-local best acceleration coefficient （GLBestAC） are incorporated into PSO in order to compute the optimal power flow solution. The proposed method has been tested on the standard IEEE 30 bus test system to prove its efficacy. The results are compared with those obtained through cPSO. It is observed that the proposed algorithm is computationally faster, in terms of the number of load flows executed and provides better results than the conventional heuristic techniques.

Measurment of gas-liquid two-phase slug flow with a Venturi meter based on blind source separation

We propose a novel flow measurement method for gas–liquid two-phase slug flow by using the blind source separation technique. The flow measurement model is established based on the fluctuation characteristics of differential pressure(DP) signals measured from a Venturi meter. It is demonstrated that DP signals of two-phase flow are a linear mixture of DP signals of single phase fluids. The measurement model is a combination of throttle relationship and blind source separation model. In addition, we estimate the mixture matrix using the independent component analysis(ICA) technique. The mixture matrix could be described using the variances of two DP signals acquired from two Venturi meters. The validity of the proposed model was tested in the gas–liquid twophase flow loop facility. Experimental results showed that for most slug flow the relative error is within 10%.We also find that the mixture matrix is beneficial to investigate the flow mechanism of gas–liquid two-phase flow.

Neural circuits and temporal plasticity in hindlimb representation of rat primary somatosensory cortex:revisited by multi-electrode array on brain slices

Objective The well-established planar multi-electrode array recording technique was used to investigate neural circuits and temporal plasticity in the hindlimb representation of the rat primary somatosensory cortex （S1 area） . Methods Freshly dissociated acute brain slices of rats were subject to constant perfusion with oxygenated artificial cerebrospinal fluid （95% O2 and 5% CO2） , and were mounted on a Med64 probe （64 electrodes, 8×8 array） for simultaneous multi-site electrophysiological recordings. Current sources and sinks across all the 64 electrodes were transformed into two-dimensional current source density images by bilinear interpolation at each point of the 64 electrodes. Results The local intracortical connection, which is involved in mediation of downward information flow across layers II-VI, was identified by electrical stimulation （ES） at layers II-III. The thalamocortical connection, which is mainly involved in mediation of upward information flow across layers II-IV, was also characterized by ES at layer IV. The thalamocortical afferent projections were likely to make more synaptic contacts with S1 neurons than the intracortical connections did. Moreover, the S1 area was shown to be more easily activated and more intensively innervated by the thalamocortical afferent projections than by the intracortical connections. Finally, bursting conditioning stimulus （CS） applied within layer IV of the S1 area could success-fully induce long-term potentiation （LTP） in 5 of the 6 slices （83.3%） , while the same CS application at layers II-III induced no LTP in any of the 6 tested slices. Conclusion The rat hindlimb representation of S1 area is likely to have at least 2 patterns of neural circuits on brain slices： one is the intracortical circuit （ICC） formed by interlaminar connections from layers II-III, and the other is the thalamocortical circuit （TCC） mediated by afferent connections from layer IV. Besides, ICC of the S1 area is spatially limited, with less plasticity, while TCC is spatially extensive and exhibits a better plasticity in response to somatosensory afferent stimulation. The present data provide a useful experimental model for further studying microcircuit properties in S1 cortex at the network level in vitro.