双流县深化农村产权制度改革的思考和建议

双流县深化农村产权制度改革的核心是赋予农民更多财产权利,内容是在坚持"确权固化、长久不变"前提下,深入推进确权颁证,畅通流转渠道,创新产权融资,自主开发集体建设用地。难点是建立农村产权流转和融资的规则,重点修改或完善城乡统一的土地产权登记制度,建立城乡统一的建设用地使用权制度,建立健全农村产权融资管理办法和配套的风险防范实施机制。规范的农村产权制度必将激发农村产权权能,保障农民财产效能价值的最大化,推进城乡建设用地同等入市,实现农村产权的市场化和资本化。

Direct computing methods for turn flows in traffic assignment

Two methods based on a slight modification of the regular traffic assignmentalgorithms are proposed to directly compute turn flows instead of estimating them from link flows orobtaining them by expanding the networks. The first one is designed on the path-turn incidencerelationship, and it is similar to the computational procedure of link flows. It applies to thetraffic assignment algorithms that can provide detailed path structures. The second utilizes thelink-turn incidence relationship and the conservation of flow on links, a law deriving from thisrelationship. It is actually an improved version of Dial's logit assignment algorithm. The proposedapproaches can avoid the shortcomings both of the estimation methods, e. g. Furness's model andFrator's model, and of the network-expanding method in precision, stability and computation scale.Finally, they are validated by numerical examples.

ReTweeting Analysis and Prediction in Microblogs: An Epidemic Inspired Approach

Microblogs currently play an important role in social communication. Hot topics currently being tweeted can quickly become popular within a very short time as a result of retweeting. Gaining an understanding of the retweeting behavior is desirable for a number of tasks such as topic detection, personalized message recommendation, and fake information monitoring and prevention. Interestingly, the propagation of tweets bears some similarity to the spread of infectious diseases. We present a method to model the tweets' spread behavior in microblogs based on the classic Susceptible-Infectious-Susceptible (SIS) epidemic model that was developed in the medical field for the spread of infectious diseases. On the basis of this model, future retweeting trends can be predicted. Our experiments on data obtained from the Chinese micro-blogging website Sina Weibo show that the proposed model has lower predictive error compared to the four commonly used prediction methods.

Sediment Movement in Periodic Alternating Current

The present paper summarizes the results of previous studies, including the structure and principle of the rotary ring flume for researching the fine sediment movement, the mechanism of the flume, method of eliminating the influence of the centrifugal force and sediment movement experiments with periodic alternating current. Also included are the experiment-based relationship among sediment concentration, bed shear stress and silt carrying capacity, a proposed erosion-deposition function and bed erosion-deposition calculation together with the results of verification.

Optimization of lane assignment for signalized T-intersection based on VISSIM

In order to improve the performance of the signalized intersection,an unconventional scheme tandem design(TD)is proposed.A simulation experiment is conducted to evaluate the capacity and delay under the unconventional scheme and two conventional lane assignment schemes.First,the VISSIM is employed as microsimulation to obtain the delay of different designs at signalized T-intersections under different conditions of traffic flow and turning proportion.Secondly,a method based on discriminant analysis(DA)is proposed to determine the best design scheme using the flow and turning proportion as inputs.Finally,a case study in Changsha city,China is used to demonstrate the efficiency and accuracy of these findings.The results indicate that the traffic flow and turning proportion are the crucial factors in scheme selection of lane assignment.Different from the previous research,the TD has better performance over various traffic flow levels.Furthermore,a proper proportion of left turns makes TD an outstanding option,which can reduce the delay and decrease the average number of stops and queue length significantly.However,the proportion should not be too high or too low.The research results can help practitioners obtain a quantitative view of appropriate design schemes at signalized intersections when trying to relieve traffic congestion according to different traffic conditions.

College English： Issues and concerns regarding grammar

The new syllabus sets the standards for college English comprehension, particularly emphasizing the students＇ need for listening and speaking. Additionally, the traditional ＂grammar-translation＂ approach has been criticized and become overlooked, while its counterpart, the ＂communicative approach＂, has become increasingly popular. The result is that ＂language communication＂ is being emphasized rather than ＂basic language core theories＂ incorporating grammar rules and this might not be totally advisable. The author analyses the present educational situation pertaining to college English education and recommends responsive strategies and an improved response towards the need for grammar education.

Interannual variability in the North Pacific meridional overturning circulation

We analyzed the temporal and spatial variation, and interannual variability of the North Pacific meridional overturning circulation using an empirical orthogonal function method, and calculated mass transport using Simple Ocean Data Assimilation Data from 1958-2008. The meridional streamfunction field in the North Pacific tilts N-S; the Tropical Cell （TC）, Subtropical Cell （STC）, and Deep Tropical Cell （DTC） may be in phase on an annual time scale; the TC and the STC are out of phase on an interannual time scale, but the interannual variability of the DTC is complex. The TC and STC interannual variability is associated with ENSO （El Nifio-Southem Oscillation）. The TC northward, southward, upward, and downward transports all weaken in E1 Nifios and strengthen in La Nifias. The STC northward and southward transports are out of phase, while the STC northward and downward transports are in phase. Sea-surface water that reaches the middle latitude and is subducted may not completely return to the vopics. The zonal wind anomalies over the central North Pacific, which control Ekman transport, and the east-west slope of the sea level may be major factors causing the TC northward and southward transport interannual variability and the STC northward and southward transports on the interannual time scale. The DTC northward and southward transports decrease during strong E1 Nifios and increase during strong La Nifias. DTC upward and downward transports are not strongly correlated with the Nifio-3 index and may not be completely controlled by ENSO.

A novel design of power management integrated circuit with 90 plus efficiency used in AC/DC converter

Recently, resonant AC/DC converter has been accepted by the industry. However, the efficiency will be decreased at light load. So, a novel topology with critical controlling mode combined with resonant ones is proposed in this paper. The new topology can correspond to a 90 plus percent of power converting. So,a novel topology of an state of art integrated circuit, which can be used as power management circuit, has been designed based on the above new topology. A simulator which is specifically suitable for the power controller has been founded in this work and it has been used for the simulation of the novel architecture and the proposed integrated circuit.

Design of a novel 50kW fast charger for electric vehicles

A novel 50 kW fast charger was proposed for electric vehicles. The proposed fast charger is divided into two main sections an AC-DC converter performing a PFC function and a DC-DC converter performing a charging function. A transformer including leakage inductances was used in the AC-DC converter in order to obtain isolation and inductance. A series-connection topology was used in the DC-DC converter between the DC-bus and outlet. This topology enables high power conversion efficiency up to 95% for the DC-DC converter. In order to reduce the impact of the 50 kW charging on the AC grid, the proposed fast charger system includes a buffering battery unit between the two main power conversion units. This leads to reductions in the power installation costs of power companies and to improvements in the power quality were verified through simulations and experimental results. on the AC grid. The performances of the proposed fast charger system

Fabrication of automatic switch for AC-DC completely automated measurement system at NIS

A fast automatic AC-DC switch is designed and fabricated mainly by a microcontroller and three double poles single throw reed relays.This new switch is introduced to establish a fully automated system for AC-DC measurements through ACDC transfer standards for the first time at the National Institute for standards(N IS)in Egypt.The implemented circuit of theautomatic AC-DC switch and its protection are presented in details.An AC voltage source is calibrated against DC voltagesource by using the demonstrated automatic switch as an application The calibrated voltage ranges are2V,6V,20V and60V as examples.The uncertainty budget is also evaluated for the calibrated values.

High-Performance AC-DC Power Electronic Converter Generator for Hybrid-Solar Vehicles

This paper describes the principles of operation and the physical model of an advanced AC-DC converter generator （with the electronic converter acting as an AC-DC rectifier with reverse-conducting MOSFETs （metal-oxide semiconductor field-effect transistors） as fast-electronic switches with a relatively low ON-state voltage drop） for HSVs. An AC-DC converter, when seen as an AC-DC rectifier, can be used in many fields, e.g., for multi-functional AC-DC/DC-AC convener generator^starter and conventional DC-AC convener motors and AC-DC converter generators or generator sets, welding machines, etc. The paper also describes a novel AC-DC convener, with reverse-conducting transistors and without the use of optoelectronic separation （which does not require a separate power supply）, which may be easily realized in IC （integrated-circuit） technology. Computer simulation allows for waveform evaluation for timing analysis of all components of the AC-DC-converter＇s physical model, both during normal operation as well as in some states of emergency. The paper also presents the results of bench experimental studies where the MOSFETs were used as fast-electronic switches with a relatively low ON-state voltage drop. For experimental studies, a novel AC-DC converter has been put together on the Mitsubishi FM600TU-3A module. The AC-DC converter with reverse-conducting transistors in a double-way connection has a lot of advantages compared to the conventional AC-DC convener acting as a diode rectifier, such as higher energy efficiency and greater reliability resulting from the lower temperature of electronic switches.

Optimization of Operational Parameters in a Three Phase AC / DC Reactive Power Compensator

AC / DC converter is a kind of devices applicable to reactive power compensation. Three parameters including losses, Total Harmonic Distortion （THD） and compensation capacity have important role in designing procedure that these parameters are affected by the firing angle. Consideration trade of between these parameters can cause be selected suitable firing angle for optimal working of the compensator. In this paper is defined an objective function which includes the above parameters. This objective function is optimized through appropriate weighting factor for any parameters and the optimal firing angle will be obtained. So, the mention parameters can be selected optimally.

Experimental Performance Assessment of Multi-Phase Alternators Supplying Multiple AC/DC Power Converters

DC distribution networks are often employed in isolated power systems like in marine and aeronautical applications. An interesting alternative to DC machines for the supply of DC grids is constituted by a three-phase alternator feeding an AC/DC rectifier. In this paper, alternative solutions are investigated where the AC alternator is equipped with more （iV） three-phase windings and feeds the DC load through more （N） cascade-connected rectifiers. The advantages of this solution with respect to the conventional three-phase topology are highlighted along with their dependence on the number （N） of the alternator windings. For this purpose, test results are reported and discussed on a prototype generator whose stator coils can be differently connected to obtained one, two, three or four windings. The major benefits （in terms of DC output current quality and field current ripple） are found when passing from the three-phase solution to the dual winding topology; conversely, relatively little advantage is gained by increasing the number of stator windings above two.

北仑区深化农村股份经济合作社改革的研究

浙江省宁波市北仑区自2002年开展村经济合作社股份合作制改革以来,通过近十年努力,于2010年底基本完成了股份合作社改革。近年来,随着城市化进程的推进,城市的规模和外延不断扩大,原城郊农村逐步纳入到城市建成区规划,成为典型"城中村",目前区内一部分村已经完成了整体拆迁并实施了撤村建居,农村股份经济合作社的存在、发展方式面临着新的挑战和选择。

A novel control strategy for load converter of DC isolated distribution system under unbalanced loading conditions

A novel control strategy for the load converter supplying the unbalanced AC load in a DC isolated distribution system is presented. The control algorithm results in balanced and sinusoidal load voltages under unbalanced AC loading. The unbalanced load is characterized in the d-q-0 rotating coordinate based on symmetrical sequence components. Also, the mathematical model of the load converter in both a-b-c and d-q-0 coordinates is derived by using the average large signal model. Then, two control strategies for the load converter are presented. The first one uses the conventional d-q-0 controller to ensure the voltage and current regulation. The second one is a newly proposed control strategy based on the decomposition of the voltage and current into in-stantaneous positive, negative, and zero sequences. These three sequences are controlled independently in their own reference frames as DC signals. The performance of the load converter using these two control strategies is compared. Simulation results show the validity and capability of the newly proposed control strategy.

Limited ecological risk of insect-resistance transgene flow from cultivated rice to its wild ancestor based on life-cycle fitness assessment

Ecological impact caused by transgene flow from genetically engineered （GE） crops to their wild rela- tives is largely determined by the fitness effect brought by a transgene. To estimate such impact is critical for the eco- logical risk assessment prior to the commercialization of GE crops. We produced F1 and F2 hybrid descendants from crosses of two insect-resistant GE rice lines （Bt, Bt/CpT1） and their non-GE rice parent with a wild rice （Oryza ruff- pogon） population to estimate the transgenic fitness. Insect damages and life-cycle fitness of GE and non-GE crop- wild hybrid descendants as well as their wild parent were examined in a common-garden experiment. No significant differences in insect damages were observed between the wild rice parent and GE hybrid descendants under high- insect pressure. The wild parent showed significantly greater relative survival-regeneration ratios than its GE and non-GE hybrid descendants under both high- and low-in- sect pressure. However, more seeds were produced in GE hybrid descendants than their non-GE counterparts under high-insect pressure. Given that the introduction of Bt and Bt/CpT1 transgenes did not provide greater insect resistance to crop-wild hybrid descendants than their wild parent, we predict that transgene flow from GE insect-resistant rice to wild rice populations may not cause considerable ecolog- ical risks.

A new cellular automaton model for traffic flow considering realistic turn signal effect

In real traffic,any vehicle must give lane-changing signal(i.e.the turn signal) before changing lanes;at this time,the vehicles behind the lane-changing vehicle will be hindered and may form "plugs" due to the turn signal effect.However,few studies focus on exploring the effect.In this paper,the turn signal effect was taken into account by proposing a new symmetric two-lane cellular automaton(T-STCA) model,and the new model was set to compare with the STCA,H-STCA and A-STCA models.Numerical results show that using the T-STCA model to describe lane-changing or overtaking,the process appeared in several consecutive time steps;while using the other three models,the process appeared only in one time step.In addition,the T-STCA model could describe the mixed traffic flow more realistically and the turn signal effect could help the plugs to dissolve more quickly.

Thermal Performance of a Single-row Fin-and-tube Heat Exchanger

Experiments were carried out to study the heat transfer characteristics of a single-row aluminum fin-and-tube crossflow heat exchanger with an emphasis in the regime of low flow rate of the in-tube fluid. The Chilton-Colburn analogy, in conjunction with the least-squares power-law technique, was used to correlate experimental data. Both air- and water-side heat transfer correlations were developed in the form of the Nusselt numbers as a function of Reynolds and Prandtl numbers. The experimental observations are quantitatively compared to the predictions of correlations available in the published literature. Different transfer mechanisms were found to be operative in the ranges of water-side Reynolds numbers based on the hydraulic diameter. In a range of Reynolds number from 1,200 to 6,000, the water-side thermal resistance accounts for less than ten percent of the overall thermal resistance. The dominant thermal resistance is always on the air-side. On the other hand, the thermal resistance of water-side is nearly equal to that of air-side in a Reynolds number range from 500 to 1,200.

Virtual speed sensors based algorithm for expressway traffic state estimation

The accurate estimation of expressway traffic state can provide decision-making for both travelers and traffic managers. The speed is one of the most representative parameter of the traffic state. So the expressway speed spatial distribution can be taken as the expressway traffic state equivalent. In this paper, an algorithm based on virtual speed sensors (VSS) is presented to estimate the expressway traffic state (the speed spatial distribution). To gain the spatial distribution of expressway traffic state, virtual speed sensors are defined between adjacent traffic flow sensors. Then, the speed data extracted from traffic flow sensors in time series are mapped to space series to design virtual speed sensors. Then the speed of virtual speed sensors can be calculated with the weight matrix which is related with the speed of virtual speed sensors and the speed data extracted from traffic flow sensors and the speed data extracted from traffic flow sensors in time series. Finally, the expressway traffic state (the speed spatial distribution) can be gained. The acquisition of average travel speed of the expressway is taken for application of this traffic state estimation algorithm. One typical expressway in Beijing is adopted for the experiment analysis. The results prove that this traffic state estimation approach based on VSS is feasible and can achieve a high accuracy.