Five New MVL Current Mode Differential Absolute Value Circuits Based on Carbon Nano-tube Field Effect Transistors(CNTFETs)

Carbon Nano-Tube Field Effect Transistors(CNTFETs) are being widely studied as possible successors to silicon MOSFETs.Using current mode has many advantages such as performing sum operation by means of a simple wired connection.Also,direction of the current can be used to exhibit the sign of digits.It is expected that the advantages of current mode approaches will become even more important with increased speed requirements and decreased supply voltage.In this paper,we present five new circuit designs for differential absolute value in current mode logic which have been simulated by CNTFET model.The considered base current for this model is 2 μA and supply voltage is 0.9 V.In all of our designs we used N-type CNTFET current mirrors which operate as truncated difference circuits.The operation of Differential Absolute Value circuit calculates the difference between two input currents and our circuit designs are operate in 8 logic levels.

A novel method to calculate the thrust of linear induction motor based on instantaneous current value

Because of the end effect, a linear induction motor （LIM） runs in an asymmetrical state even though the winding of each phase is symmetric. Based on the basic principle of the LIM, a new approach was proposed to calculate the thrust of the LIM using the instantaneous current value. A three-phase LIM model with 12 slots and a singlelayer winding was designed to validate this method. The experiments show that when the current is small, the calculated results basically agree with the experiments. The agreement becomes worse with the increase of the current because of the saturation of the primary iron core. The proposed formula is suitable when the iron core of the LIM primary is in an unsaturated state.

Temperature Stimulation of Effective Value of Density of the Current of Semiconductor Solar Cells

Influence of temperature on effective value of a current density of a semiconductor solar cell is investigated. New equations for explanation of dependence of photovoltaic characteristics of solar cell from temperature are received.

A method to calculate design tide levels on the basis of numerical model of tidal current and its application

In order to determine the design tide levels in the areas without measured tide level data, especially in the areas where it is difficult to measure tidal levels, a calculation method based on a numerical model of tidal current is proposed. The essentials of the method are described, and its application is illustrated with an example. The results of the application show that the design tide levels calculated by the method are close to those determined by long-time measured tide level data, and its calculation precision is high, so it is feasible to use the method to determine the design tide levels in the areas.

AUV-Aided Data Collection Considering Adaptive Ocean Currents for Underwater Wireless Sensor Networks

Autonomous underwater vehicle(AUV)-assisted data collection is an efficient approach to implementing smart ocean.However,the data collection in time-varying ocean currents is plagued by two critical issues:AUV yaw and sensor node movement.We propose an adaptive AUV-assisted data collection strategy for ocean currents to address these issues.First,we consider the energy consumption of an AUV in conjunction with the value of information(VoI)over the sensor nodes and formulate an optimization problem to maximize the VoI-energy ratio.The AUV yaw problem is then solved by deriving the AUV's reachable region in different ocean current environments and the optimal cruising direction to the target nodes.Finally,using the predicted VoI-energy ratio,we sequentially design a distributed path planning algorithm to select the next target node for AUV.The simulation results indicate that the proposed strategy can utilize ocean currents to aid AUV navigation,thereby reducing the AUV's energy consumption and ensuring timely data collection.

Selection and Application of Current Affairs and Politics Materials in Political Classroom Teaching in Senior High School

Based on the status quo of political education in high school,current affairs and politics materials are utilized as an example in this paper to analyze and discuss the value of the proper use of current affairs and politics materials in high school political classroom teaching.In addition,the paper also discusses the principles that should be adhered to in selecting materials for use in political classroom teaching.The purpose of this article is to provide guidelines to high school political subject teachers in selecting and applying the current affairs and politics materials reasonably.

全球价值链下我国制鞋业的现状及升级对策

随着制鞋行业竞争的加剧,国内行业越来越重视对市场的分析及研究。本文讨论了全球价值链背景下我国制鞋业的生产、出口及进口现状,分析我国制鞋业面临的压力,并提出针对性的措施,希望能够促进我国制鞋业的转型升级,成为经济增长的重要引擎,在全球价值链构建中发挥越来越大的作用。

小级差需求下基于故障首半波比较的快速电流保护

基于时间级差配合的梯级电流保护受限于出口线路保护动作时间,为缩短保护研判时间,提升配电网多级配合能力,提出一种小级差需求下基于故障首半波比较的快速电流保护方法。对传统电流保护动作时间进行分析,采用整定值构建模板曲线,与故障电流采样值进行多点动态比较,基于有效值爬坡效应及采样值越限效应构建新的保护启动判据、考虑保护算法延迟及干扰点的影响构建新的动作判据,综合加快电流保护判别速度。利用PSCAD/EMTDC软件仿真验证了所提方法在不同类型故障、不同故障时刻、负荷突增、干扰影响等工况下的有效性,结果表明所提方法的动作时间不超过10 ms,有利于小级差更加灵活和可靠的整定。

小黑豆中活性成分·营养价值与资源应用

黑豆为大豆属植物[Glycine max(L.)Merr]的种子,为我国资源分布很广的药食两用中药,陕北小黑豆为其栽培品种之一。黑豆主要含有异黄酮和花青素类成分,具有抗炎、抗氧化、降血糖、降血脂、抗癌、调节激素水平等多种药理作用。对1997—2022年国内外文献报道的黑豆化学成分及主要药理作用进行综述,分析陕北小黑豆种植栽培现状及药用黑豆存在的问题。提出陕北地区的环境更适合小黑豆的种植与进一步应完善该植物药材标准的观点。

面向学科建设的高校图书馆决策情报服务分析

随着时代的发展,新时期高校图书馆有着新的发展目标,需要在“双一流”的背景下,做好针对学科建设的决策情报服务工作,有效提高学校中的学科管理质量,使高校具有较高的竞争力。不过从参考的部分高校图书馆的决策情报服务工作看,多方因素干扰下,决策情报服务容易受到影响,如何有效落实决策情报服务工作,也成为当前高校图书馆运行中需要考虑的问题。为此,分析决策情报服务的价值、现状,最后提出对应的处理策略,以期满足高校的发展需要。

基于实测数据的地铁车站强电设备发热量影响因素分析

如果地铁车站强电设备管理用房的空调系统设计缺少可靠的设备发热量参数,不利于地铁空调系统的优化设计和节能减排。提出一种地铁车站强电设备管理用房空调设备发热量计算与分析方法,并在郑州地区4种地铁车站中进行应用,研究室内空气温度、地铁是否运营、设备额定功率和车站类型等因素对地铁强电设备管理用房设备发热量的影响。结果显示:室内气温虽然对设备外表面温度有较大影响,但是对设备外表面热流密度和设备发热量的影响较小。地铁运营期间的设备发热量大于非营运期间的设备发热量,设备发热量低于设备额定功率。

并网逆变器最优开关序列模型预测电流控制

传统的并网逆变器模型预测电流控制方法仅在控制周期内对电流波形进行单点预测,忽略了逆变器开关状态变化引起的输出电流纹波,为此提出一种改进的最优开关序列并网逆变器模型预测电流控制策略。首先,为减小开关切换次数、优化频谱分布,对空间电压矢量组合进行重新排列,设计6组开关序列,并根据开关序列提出基于无差拍的矢量持续时间计算方法。其次,在一个控制周期内设置8个电流预测点,以计算开关序列在控制周期内作用所产生的电流预测误差,并通过累加电流预测误差构造预测控制的价值函数,选择使价值函数最低的开关序列作为最优序列组合,提高并网电流波形质量。最后,通过实验验证所提策略在降低并网逆变器输出电流纹波方面的有效性。

闽南侨批蕴含的文化内涵、时代价值及实践理路

闽南侨批被誉为“世界记忆遗产”,它是闽南华侨情系故里、热爱祖国、爱拼敢赢的历史见证。通过阐述闽南侨批蕴含的亲缘文化、爱国主义精神与诚信文化等内涵,分析闽南侨批具有维护亲情关系,传承传统孝德文化;建设社会道德,彰显崇德向善理念;培育爱国精神,凝聚社会价值共识;维持国际关系,促进经济文化交流等方面的时代价值。提出以家庭教育为沃土传递侨批精神品格、以多元传播为牵引讲好侨批爱国故事、以保护机制为抓手发掘侨批历史价值、以外部环境为保障强化侨批文化交流、以数字技术为依托拓展侨批文化空间、以文艺作品为基点弘扬侨批文化精神等实践理路,发挥闽南侨批独具特色的时代价值。

我国医疗机构药学门诊开展现状调查

目的调查我国医疗机构药学门诊现状,为促进药学门诊发展提供经验和建议。方法采用问卷调查法,于2023年3-4月调查全国31个省(自治区、直辖市)医疗机构药学门诊的开展情况,对结果进行描述性分析,并对药学门诊服务量的影响因素进行回归分析。结果本次调研共发放问卷1368份,收回有效问卷1304份,问卷有效回收率为95.32%。有463家医疗机构开展了药学门诊,药学门诊开展率为35.51%(463/1304),其中三级、二级、一级及其他医疗机构药学门诊的开展率分别为52.80%、17.18%、5.88%。药学门诊开设频率为平均每周3.17 d,平均每家医疗机构有出诊药师5.99名,出诊药师中临床药师占绝大多数(88.68%,2459/2773)。受访医疗机构开设的药学门诊类别多样,包括联合门诊和药师独立门诊,以药师独立门诊中的药学专科/专病门诊为主,占药学门诊总数量的89.72%。药学门诊出诊药师的价值体现形式多样,其中对药学门诊收费的医疗机构占比为10.80%。受访医疗机构开展药学门诊的主要经验是重视学科建设和重视人才培养,面临的主要困难是补偿水平低和符合要求的人才严重不足。临床药师人数、药学门诊出诊药师人数、有额外补偿与药学门诊服务量呈显著正相关(P<0.05)。结论我国医疗机构药学门诊取得了较大发展,今后仍需进一步加强学科建设和人才培养,重视出诊药师的价值体现,以促进药学门诊健康发展。

基于光伏动态电流参考值的两级式光伏并网系统低电压穿越控制策略

随着光伏接入容量的不断提升,电网电压跌落时光伏脱网会影响系统稳定运行,因此光伏系统应具备低电压穿越(LVRT)能力。然而,目前常用的两级式光伏并网系统LVRT控制策略存在光伏动态响应慢及控制效果受限于光伏P–U特性曲线的数学模型精度等问题,且未考虑局部阴影条件下的适用性。基于此,提出一种基于光伏动态电流参考值的LVRT控制策略。首先,在建立两级式光伏并网系统及光伏电池P–U特性数学模型的基础上,分别对目前常用的基于定直流母线电压和基于光伏P–U特性曲线的LVRT控制的原理及不足进行了分析。其次,针对前级boost电路的控制构造了具有自适应收敛特性的光伏输出电流动态参考值以对光伏工作点进行直接调整。该策略无需对光伏P–U特性曲线数学模型进行求解,避免求解误差的同时加快了光伏动态响应速度。此外,在最大功率跟踪(MPPT)算法中引入故障解耦模块,在电网低电压故障期间对MPPT输出电压参考值进行锁定,避免MPPT无效运算带来的电压参考值偏移,使系统在故障结束时能以最快速度恢复至最大功率点。最后,通过仿真将所提策略与目前常用的基于定直流母线电压和基于光伏P–U特性曲线的LVRT控制策略在多种环境条件下进行对比。仿真结果表明:与定直流母线电压控制策略相比,所提策略下光伏动态响应快;与现有基于光伏P–U特性曲线的控制策略相比,所提策略不受P–U特性误差的影响,在辐照度变化尤其局部阴影条件下均能很好地实现低电压穿越。

Progress in inhomogeneity of critical current and index n value measurements on HTS tapes using contact-free method

The development of high temperature superconducting(HTS)tapes has recently made great progress,and Bi-based tapes(1 G) and YBCO coated conductor(2 G)are commercially fabricated with practical length.Application of HTS in electric power apparatuses made important achievement,various superconducting devices were demonstrated in grid,laying solid foundation for their commercialization.However,since their intrinsic microscopic defects such as weak-link,granularity,small second phase likely exist,critical current and index n value of the HTS tapes in practical length are impossible homogeneous,which have significant influences on safety,stability and efficiency of the HTS apparatuses.Therefore,critical current and index n value are two important parameters describing inhomogeneity of HTS tapes,thus two important indices for evaluating quality of practical long HTS tapes.This paper focuses on main progresses in inhomogeneity of critical current and index n value measurements on HTS tapes using contact-free methods.The statistical analytical methods evaluating the inhomogeneity of critical current and index n value are suggested.They can provide essential references for design and operation of HTS apparatuses.

BDD电极对苯酚降解氧化的试验研究

基于掺硼金刚石(BDD)电极的电化学高级氧化技术是解决难降解有机污染物的有效方法之一。通过热丝化学气相沉积法(Hot Filament CVD,HFCVD)结合动态掺硼工艺,在WC-Co衬底上成功合成了BDD薄膜。在此基础上,利用已制备的WC-Co/BDD电极,以苯酚为目标污染物,探究了不同电流密度、电解质浓度、pH值、苯酚初始浓度对其降解效率的影响。试验结果显示,在电流密度为0.03 A/cm^(2),电解质为1.5 g/L Na_(2)SO_(4)的条件下,无论是在酸性还是碱性环境中,对于质量浓度为1000 mg/L的苯酚溶液,3 h内COD的去除率均达到95%;对于质量浓度低于500 mg/L的苯酚溶液,其COD去除率在相同时间内均接近100%。基于WC-Co/BDD电极的电化学高级氧化技术对苯酚的矿化效果极为显著。

乙二胺作为电解锰新型pH调节剂

锰电解过程在(NH_(4))_(2)SO_(4)-MnSO_(4)体系进行时,需维持电解液pH值稳定在7.0~7.2。但阳极析氧反应使得长期电解条件下电解液pH值不断下降。生产上均使用氨水调节电解液pH值。但氨水易挥发,导致整个生产车间氨气味道刺鼻,影响身体健康。此外,持续加入氨水造成电解液中的氨不断累积膨胀,最终产生大量氨氮废水和氨氮锰渣。鉴于乙二胺与氨水的化学性质相似性,且具备更强的碱性及更低的挥发性,探索以乙二胺取代氨水作为pH值调节剂,以减少氨源的使用量、改善作业环境,探究乙二胺新体系电解锰的可行性。

基于电流值分析的三相逆变器开关管开路故障诊断方法

三相逆变器因能将电能从直流电源高效率地转换为频率和幅度灵活可变的交流电压,在现代工业和能源领域发挥着重要作用。为解决三相逆变器开关管开路故障对系统正常稳定运行造成严重影响问题,提出一种基于相电流值分析的三相逆变器单开关和双开关开路故障诊断方法。首先详尽分析了每个开关管发生开路故障后对相电流的输出值产生的影响。在开关管发生开路故障后,相电流的输出值的最大值不会超出额定幅值的1/3。重点分析了逆变器同侧的双开关同时发生开路故障的电流特性,总结成表,有效消除了以往基于电流的诊断方法中遇到的误诊问题。将每个开关管会被影响的电流波形作为故障检测波形,通过检测起始零点可以获得每个开关管对应的故障检测波形。然后通过统计每个故障检测波的采样值数量是否达到判定函数的条件来快速检测逆变器开关的开路故障。通过半实物仿真平台进行三相逆变器开路故障的实验,验证方法的有效性和准确性。实验展开了对不同类型的三相逆变器开关管开路故障的诊断,实验结果证明了方法能精确地位到不同类型的三相逆变器开路故障,同时也对负载变化的运行情况下的故障诊断表现出高鲁棒性。方法具有快速故障检测、精确定位故障、计算负担低的特点。