基于能路的综合能源系统安全域稳态建模与求解

安全域是综合能源系统(IES)安全分析的重要手段,但异质能源遵循不同的物理传输过程与数学表征方式,给综合能源系统安全域(IES-SR)的统一建模与求解带来了困难。为此,考虑异质能源传输特征的差异性与网络特征的相似性,提出了多能源耦合系统的基于能路的安全域模型,在稳态建模层面上实现了电-气IES-SR的数学形式统一。首先,给出了电-气IES-SR的基础概念;其次,介绍了异质能源统一建模方法的能路模型,其异质能源网络方程在数学形式上具有一致性;进而,在能路基础上建立了IES-SR模型,实现了电力系统安全域、天然气系统安全域和IES-SR模型的数学形式统一;再次,提出了高维IES-SR安全边界拟合求解方法;最后,采用8节点测试算例和23节点实际算例进行了验证。与现有研究对比表明,文中首次得到了高维安全域的完整解析式,采用线性化方法同时提高了求解效率。所提模型易于扩展至其他类型的能源系统,并为后续考虑动态特性的IES-SR建模奠定了基础。

综合能源系统分析的统一能路理论(二):水路与热路

供热网络是综合能源系统的重要组成部分。作为系列论文的第二部分,该文以供热网络为对象,基于质量守恒方程和动量守恒方程推导了水路模型,基于能量守恒方程推导了热路模型,并通过傅里叶变换和二端口等值实现了模型向代数方程的化简,最后基于水路模型与热路模型刻画了供热网络的支路特性与拓扑约束,并由此导出了水力网络方程和热力网络方程。此外,根据供热网络的水力运行特点,完成了动态水路向稳态水路的退化并提出了修正解法。算例结果表明了水路与热路方法分析供热网络的有效性。与传统分析方法相比,热路方法可以描述时域中连续的热力动态过程,在满足计算精度的同时,显著降低了网络分析的计算复杂度。

综合能源系统分析的统一能路理论(一):气路

综合能源系统已成为国内外研究的热点与前沿,为实现不同能源网络研究的学科融合,基于电路理论中"场"到"路"的推演方法论,提出统一能路理论。作为系列论文的第一部分,该文以天然气网络为对象,基于质量守恒与动量守恒方程推导了分布参数的时域气路模型,利用傅里叶变换将气路映射至频域并通过二端口等值得到集总参数模型,实现了气路模型从偏微分方程向代数方程的简化。最后基于气路模型导出了天然气网络的网络矩阵和网络方程,与电力网络的网络矩阵和网络方程在数学形式上具有高度的统一性,从而奠定了气、电2种异质能流统一分析的理论基础。相比传统分析方法,气路方法具有更低的计算复杂度,算例结果表明其在计算效率上有显著优势。

综合能源系统分析的统一能路理论(三):稳态与动态潮流计算

潮流计算作为能源网络分析的基础性应用,在各能源网络已形成成熟但不统一的计算模型与方法。为促进不同能源网络研究的学科融合,该文基于统一能路理论,针对天然气网络与供热网络,提出了相适应的潮流计算方法。在此基础上,补充了基值修正的迭代方法以提高潮流计算的精度,并应用了"边值–初值"等效的方法以在动态潮流计算中隐式地给定初始条件。基于统一能路的潮流计算方法不仅统一了不同能源网络的潮流计算,还统一了同一能源网络内的稳态潮流计算与动态潮流计算,奠定了多异质能流在多时间尺度上统一分析的应用基础。此外,相较以有限差分方法为代表的传统动态潮流计算方法,文中所提出的方法在计算性能上实现了显著的提升。

综合能源系统分析的统一能路理论(四):天然气网动态状态估计

天然气网是综合能源系统的重要组成部分,为实现其能量管理,需要利用状态估计技术获取实时、可靠、一致、完整的网络状态信息。然而,实际天然气网络的流量、压力调节较为频繁,现有的稳态状态估计模型无法考虑网络的动态过程。该文基于统一能路理论中的气路模型,首次建立了天然气网络的动态状态估计模型,将管道中复杂的时域偏微分方程转化为了易于优化求解的频域线性代数方程,进一步测试了模型在状态估计精度和坏数据辨识方面的性能。算例表明,所建立的模型可有效过滤量测噪声和坏数据,补齐系统缺失量测,准确估计天然气网络的动态过程。

综合能源系统分析的统一能路理论(五):电–热–气耦合系统优化调度

多能流系统耦合调度相比独立调度可以有效降低运行成本,提高可再生能源消纳,目前已经成为一大研究热点。但是,现有的研究大多采用稳态的热网和天然气网模型,这一方面忽略动态特性中蕴含的调度灵活性,另一方面还可能导致调度结果不准确,引发安全问题。该文基于统一能路理论,建立一种新的电–热–气耦合多能流系统优化调度模型,将描述热网和天然气网络动态的复杂偏微分方程转化为线性复代数方程,易于优化求解。此外,统一能路模型是基于偏微分方程的解析解推导的,具有高精度。算例表明,文中建立的优化调度模型可以利用热网和天然气网的动态特性来提高调度灵活性,降低系统运行成本。相比已有方法,文中建立的优化调度模型具有求解速度快、模型精度高的优点。

Mechanical response and dilatancy characteristics of deep marble under different stress paths:A sight from energy dissipation

Dilatancy is a fundamental volumetric growth behavior observed during loading and serves as a key index to comprehending the intricate nonlinear behavior and constitutive equation structure of rock.This study focuses on Jinping marble obtained from the Jinping Underground Laboratory in China at a depth of 2400 m.Various uniaxial and triaxial tests at different strain rates,along with constant confining pressure tests and reduced confining pressure tests under different confining pressures were conducted to analyze the mechanical response and dilatancy characteristics of the marble under four stress paths.Subsequently,a new empirical dilatancy coefficient is proposed based on the energy dissipation method.The results show that brittle failure characteristics of marble under uniaxial compression are more obvious with the strain rate increasing,and plastic failure characteristics of marble under triaxial compression are gradually strengthened.Furthermore,compared to the constant confining pressure,the volume expansion is relatively lower under unloading condition.The energy dissipation is closely linked to the process of dilatancy,with a rapid increase of dissipated energy coinciding with the beginning of dilatancy.A new empirical dilatancy coefficient is defined according to the change trend of energy dissipation rate curve,of which change trend is consistent with the actual dilatancy response in marble under different stress paths.The existing empirical and theoretical dilatancy models are analyzed,which shows that the empirical dilatancy coefficient based on the energy background is more universal.

SI-INSPIRED ENERGY AWARE QoS ROUTING TREE FOR WSN

A heuristic theoretical optimal routing algorithm （TORA） is presented to achieve the data-gathering structure of location-aided quality of service （QoS） in wireless sensor networks （WSNs）. The construction of TORA is based on a kind of swarm intelligence （SI） mechanism, i. e. , ant colony optimization. Firstly, the ener- gy-efficient weight is designed based on flow distribution to divide WSNs into different functional regions, so the routing selection can self-adapt asymmetric power configurations with lower latency. Then, the designs of the novel heuristic factor and the pheromone updating rule can endow ant-like agents with the ability of detecting the local networks energy status and approaching the theoretical optimal tree, thus improving the adaptability and en- ergy-efficiency in route building. Simulation results show that compared with some classic routing algorithms, TORA can further minimize the total communication energy cost and enhance the QoS performance with low-de- lay effect under the data-gathering condition.

Characterizing uncertainty in pavement performance prediction

Taking variability and uncertainty involved in performance prediction into account, in order to make the prediction reliable and meaningful, a distribution-based method is developed to predict future PSI. This method, which is based on the AASHTO pavement performance model, treats predictor variables as random variables with certain probability distributions and obtains the distribution of future PSI through the method of Monte-Carlo simulation. A computer program PERFORM using Monte Carlo simulation is developed to implement the numerical computation. Simulation results based on pavement and traffic parameters show that traffic, surface layer material property, and initial pavement performance are the most significant factors affecting pavement performance. Once the distribution of future PSI is determined, statistics such as the mean and the variance of future PSI are readily available.

Adaptive and distance-driven power control scheme in mobile ad hoc networks

In order to save the energy and reduce the latency of the end-to-end transmission in mobile ad hoc networks an adaptive and distance-driven power control ADPC scheme is proposed by means of distance research in random geometrics. Through mathematical proof the optimal number of relay nodes and the optimal location of each node for data transmission can be obtained when a distance is given.In the ADPC first the source node computes the optimal number and the sites of the relay nodes between the source and the destination nodes.Then it searches feasible relay nodes around the optimal virtual relay-sites and selects one link with the minimal total transmission energy consumption for data transmission.Simulation results show that the ADPC can reduce both the energy dissipation and the end-to-end latency of the transmission.

Experimental study of pavement performance of basalt fiber-modified asphalt mixture

To discuss the pavement performance of basalt fiber-modified asphalt mixtures,the optimum dosages of asphalt and fibers are studied by the Marshall test and the rutting test.The results demonstrate that the optimum dosages of asphalt and fibers are 4.63% and 0.3%,respectively.Then the pavement performances of basalt（polyester,xylogen）fiber-modified asphalt mixtures are investigated through high temperature stability tests,water stability tests and low temperature crack resistance tests.It indicates that the pavement performances of the fiber-modified asphalt mixtures such as rutting dynamic stability,freezing splitting tensile strength,low temperature crack resistance and so on are improved compared with control asphalt mixture.The results show that the pavement performances of asphalt mixtures can be improved by fiber-modifiers.Besides,the improvement effects of basalt fiber are superior to polyester fiber and xylogen fiber.

Capacity model of on-rampmerging section of urban expressway

To establish the empirical capacity model of an on- ramp merging section, the Erlang distribution is first selected to define the time headway distribution, and then the gap acceptance theory is applied to develop the basic capacity model of the on-ramp merging section. Since not all the time headways on the shoulder lane can be made full use of by on- ramp vehicles, a modified capacity model is developed, which takes the usage probability of time headway into consideration. Then, a model of capacity discount coefficient ~： is developed. Finally, based on the modified capacity model and the model of capacity discount coefficient, an empirical merge capacity model which contains the shoulder lane volume, critical gap, and the distance from nose to merging point, is constructed. Results show that, compared with other models, the proposed model is more reasonable since it takes merging section geometry into consideration, and it is easy to apply. The merge capacity varies with the shoulder lane volume, the critical gap, the distance between the nose and the merging point, and the design velocity of the shoulder lane and ramp.

Energy conversion of rocks in process of unloading confining pressure under different unloading paths

Based on energy theory and tests of rocks with initial confining pressures of 10, 20 and 30 MPa under different unloading paths, the processes of strain energy conversion were investigated. The absorbing strain energy for axial compression, the dissipating strain energy for plastic deformation and cracks propagation, the expending strain energy for circumferential deformation, and the storing and releasing elastic strain energy were considered. Unloading paths included the condition of fixing axial pressure and unloading axial pressure, increasing axial pressure and unloading confining pressure, as well as unloading axial pressure and confining pressure simultaneously. Results show that expending strain energy for circumferential deformation has mainly evolved from absorbing strain energy for axial compression in three unloading paths during unloading processes. Dissipating strain energy is significantly increased only near the peak point. The effect of initial confining pressure on strain energy is significantly higher than that of unloading path. The strain energy is linearly increased with increasing initial confining pressure. The unloading path and initial confining pressure also have great influence on the energy dissipation. The conversion rate of strain energy in three paths is increased with increasing initial confining pressure, and the effect of initial confining pressure on conversion rate of strain energy is related with the unloading paths.

Design and Realization of Simple Intelligent Robotic Lawn Mower Based on Arduino Mega2560

Robotic lawn mowers available in markets are much more complicated with high cost, hence, a new robot is designed in the research. In detail, the control system is made up of Arduino Mega2560 and 11 sensors and the robot works with four wheels （two front and back wheels） driven by an electric motor. Furthermore, the platform of lawn-mowing is designed semicircle, equipped with three small high- speed and low-power electric motors; the cutting distance is determined by width of motherboard. In addition, the hardware of the system is made up of circuit control and working machines, of which the former includes a single chip unit, a wireless remote control, a sensor unit, an infrared array module, a driving module of electric motor, a display unit and a power source; the latter includes a mowing platform and a sensor window. In addition, the related software is programmed using C language and modular programming involving PWM program, Hall sensor program, liquid-crys- tal display, tilt program, supersonic sounding program, infrared obstacle-avoidance program, parking program, and remote control program. After hardware was adjust- ed, the robotic lawn mower was tested for multiple times in a standard lawn, and a satisfied effect was achieved.

Design of dense gap-graded friction course mixture

The design procedure of a dense gap-graded friction course（DGGFC） with coarse aggregate void filling method is presented. Testing results show that a DGGFC mixture possesses a dense stone-matrix structure, good stability and almost the same texture depth as stone matrix asphalt （SMA）. It also has a coarse and even surface after paving and has no separation during construction. It is durable and impermeable. It balances and improves the inherent inconsistency of asphalt mixture between the large texture depth for skid resistance and the impermeability for durability. The actual application in the Nanning-Liuzhou Expressway also shows that the performance of the DGGFC is as excellent as that of SMA, while the DGGFC mixture is cheaper than SMA. The DGGFC mixture is good for wearing course of pavement. Further research on DGGFC can be helpful for improving the surface skid resistance, prolonging the life-span period and reducing the construction costs of asphalt pavement.

Visual object-oriented application for lane following on intelligent highway system

A visual object-oriented software for lane following on intelligent highway system (IHS) is proposed. According to object-oriented theory, 3 typical user services of self-check, transfer of human driving and automatic running and abnormal information input from the sensors are chosen out. In addition, the functions of real-time display, information exchanging interface, determination and operation interweaving in the 3 user services are separated into 5 object-oriented classes. Moreover, the 5 classes are organized in the visual development environment. At last, experimental result proves the validity and reliability of the control application.

A New Type of Power Clock for DSCRL Adiabatic Circuit

An asymmetry power clock,4 phase power clock supplying the power to the DSCRL(dual swing charge recovery logic) adiabatic circuit is presented.It is much simpler than the 6 phase power clock,symmetry power clock,used in the DSCRL adiabatic circuit.Although the 4 phase power clock is simpler,the DSCRL adiabatic circuit still shows good performance and high efficiency of energy transfer and recovery.This conclusion has been proved by the result of the HSPICE simulation using the 0 6μm CMOS technology.

Power consumption in a field emission panel

The power consumption and electric field distribution in a field emission display （FED） panel is optimized with a novel pixel structure. A circuit model is proposed to estimate the total power consumption in an FED panel which is composed of anode energy consumption, energy loss due to the leakage current and the energy dissipated in the parasitic capacitances. Moreover, the parasitic capacitances play a vital part in the power consumption and driving performance. In order to lower the parasitic capacitances, multiple dielectric layers are used as the gate electrode. Due to different etching speeds, a novel pixel structure is formed. As a result, the power consumption of an FED panel is reduced by 28% in a full white picture, and the electron beam performance is also better than that of the conventional structure.

Integrated circuit for single channel neural signal regeneration

Based on the 4-channel neural signal regeneration system which is realized by using discrete devices and successfully used for in-vivo experiments on rats and rabbits, a single channel neural signal regeneration integrated circuit （IC）is designed and realized in CSMC ＇ s 0. 6 μm CMOS （ complementary metal-oxide-semiconductor transistor ） technology. The IC consists of a neural signal detection circuit with an adjustable gain, a buffer, and a function electrical stimulation （FES） circuit. The neural signal regenerating IC occupies a die area of 1.42 mm × 1.34 mm. Under a dual supply voltage of ±2. 5 V, the DC power consumption is less than 10 mW. The on-wafer measurement results are as follows： the output resistor is 118 ml）, the 3 dB bandwidth is greater than 30 kHz, and the gain can be variable from 50 to 90 dB. The circuit is used for in-vivo experiments on the rat＇ s sciatic nerve as well as on the spinal cord with the cuff type electrode array and the twin-needle electrode. The neural signal is successfully regenerated both on a rat＇ s sciatic nerve bundle and on the spinal cord.

A Novel High-Voltage Detector Integrated into SPIC by Using FFLR

A novel high voltage detector that can be integrated into SPIC (Smart Power IC) is proposed.The structure is designed on the basis of normal junction terminal technique of FFLR (Floating Field Limiting Rings) system.The field limiting ring as a voltage divider,is used to optimize the surface field.The voltage of main junction increases from 0 to a high value,while the utmost ring is designed to vary within a small range,which can be handled by using low voltage logic circuits.An example of 400V rings system is analyzed and simulated for this structure.The results prove that the high voltage detector can detect high voltage in SPIC.The structure can be integrated into SPIC.Besides,it is compatible with CMOS or BCD(Bipolar CMOS Dmos) technology,without any additional processes required.