非分段GaN HEMT EF2类功率放大器理论研究

目前,增强型氮化镓高电子迁移率晶体管(GaN HEMT)的仿真模型存在仿真时间长、复杂度高且收敛性不好等问题。为了解决GaN HEMT器件在电力电子电路中仿真收敛性和准确性差的问题,提出一种非分段的GaN HEMT SPICE模型。使用非分段连续方程对GaN HEMT器件的静态和动态特性进行建模;再对GaN HEMT的输出特性进行仿真,并与Si MOSFET的仿真结果进行对比。仿真结果表明,所提模型的收敛性较好,收敛速度快,有较高的准确性。另外,将此模型应用于EF2类功率放大器中,研究该模型对传输效率的影响。仿真结果进一步表明:该模型具有良好的收敛性;且当开关频率为10~20 MHz,输入功率为75 W时,输出功率可达73 W,传输效率为95%,这也证明了GaN HEMT器件可以提高EF2类功率放大器的传输效率。

绵羊肺炎支原体EF-Tu蛋白的原核表达及多克隆抗体制备

[目的]克隆绵羊肺炎支原体(Mycoplasma ovipneumoniae,Mo)EF-Tu基因,原核表达获得EF-Tu蛋白,制备抗EF-Tu蛋白的兔源多克隆抗体,为研究肺炎支原体EF-Tu蛋白的结构和功能奠定基础。[方法]采用重叠延伸PCR方法将pET-28a-EF-Tu质粒中EF-Tu基因中间的TGA密码子突变为TGG,并对测序结果与其他支原体参考株进行相似性比对和遗传进化分析,利用在线软件对其推测的蛋白序列进行生物信息学分析。将突变后的重组质粒转化大肠杆菌BL21(DE3)感受态细胞进行原核表达,经SDS-PAGE和Western blotting鉴定,利用镍柱亲和层析法纯化,以纯化的EF-Tu融合蛋白免疫家兔制备多克隆抗体,采用间接ELISA和Western blotting检测多克隆抗体效价及免疫反应性。[结果]试验成功突变了EF-Tu基因中TGA位点,并构建了融合表达His标签pET-28a-EF-Tu′原核表达载体。生物信息学分析表明,克隆的EF-Tu基因与绵羊肺炎支原体MoGH3-3菌株相似性最高,亲缘关系最近;编码387个氨基酸,无N-糖基化位点和跨膜区域,存在10个丝氨酸、20个苏氨酸、4个酪氨酸磷酸化位点,二级结构由无规则卷曲(35.14%)、α-螺旋(26.87%)、延伸链(26.87%)及β-转角(11.11%)构成。SDS-PAGE和Western blotting结果显示,目的蛋白大小约为43 ku,蛋白纯化浓度为0.615 g/L。ELISA和Western blotting结果显示,制备的多克隆抗体效价可达1∶128 000,能够特异性识别EF-Tu融合蛋白,具有良好的免疫反应性。[结论]本研究成功突变了EF-Tu基因的TGA密码子,原核表达并纯化获得EF-Tu融合蛋白,制备其多克隆抗体效价为1∶128 000,为后续研究肺炎支原体EF-Tu蛋白结构和生物学功能及其疫苗研发提供了试验基础。

Efficient H_(2)O_(2)Electrosynthesis and Its Electro-Fenton Application for Refractory Organics Degradation

Hydrogen peroxide(H_(2)O_(2))in situ electrosynthesis by O_(2)reduction reaction is a promising alternative to the conventional Fenton treatment of refractory wastewater.However,O_(2)mass transfer limitation,cathodic catalyst selectivity,and electron transfer in O_(2)reduction remain major engineering obstacles.Here,we have proposed a systematic solution for efficient H_(2)O_(2)generation and its electro-Fenton(EF)application for refractory organic degradation based on the fabrication of a novel ZrO_(2)/CMK-3/PTFE cathode,in which polytetrafluoroethylene(PTFE)acted as a hydrophobic modifier to strengthen the O_(2)mass transfer,ZrO_(2)was adopted as a hydrophilic modifier to enhance the electron transfer of O_(2)reduction,and mesoporous carbon CMK-3 was utilized as a catalyst substrate to provide catalytic active sites.Moreover,feasible mass transfer of O_(2)from the hydrophobic to the hydrophilic layer was designed to increase the contact between O_(2)and the reaction interface.The H_(2)O_(2)yield of the ZrO_(2)/CMK-3/PTFE cathode was significantly improved by approximately 7.56 times compared to that of the co nventional gas diffusion cathode under the same conditions.The H_(2)O_(2)generation rate and Faraday efficiency reached125.98 mg·cm^(-2)·h^(-1)(normalized to 5674.04 mmol·g^(-1)·h^(-1)by catalyst loading)and 78.24%at-1.3 V versus standard hydrogen electrode(current density of-252 mA·cm^(-2)),respectively.The high H_(2)O_(2)yield ensured that sufficient OH was produced for excellent EF performance,resulting in a degradation efficiency of over 96%for refractory organics.This study offers a novel engineering solution for the efficient treatment of refractory wastewater using EF technology based on in situ high-yield H_(2)O_(2)electrosynthesis.

C_(80EF)型通用敞车转向架基础制动装置孔位调整技术研究

文中简要介绍了C_(80EF)型通用敞车基础制动装置的结构。结合C_(80EF)型通用敞车基础制动装置运用检修实际,从转向架基础制动装置、ST2-250型闸瓦间隙调整器(简称“闸调器”,下同)关键参数等方面对轮瓦磨耗量的影响进行了详细分析,并得出了轮瓦磨耗量与支点、下拉杆及闸调器参数间的关系。根据C_(80EF)型通用敞车车轮磨耗调研数据,制定出适合该车型的转向架基础制动装置孔位调整规则,并适当验证了其分析的正确性。

Artificial Intelligence for Maximizing Agricultural Input Use Efficiency: Exploring Nutrient, Water and Weed Management Strategies

Agriculture plays a crucial role in the economy,and there is an increasing global emphasis on automating agri-cultural processes.With the tremendous increase in population,the demand for food and employment has also increased significantly.Agricultural methods traditionally used to meet these requirements are no longer ade-quate,requiring solutions to issues such as excessive herbicide use and the use of chemical fertilizers.Integration of technologies such as the Internet of Things,wireless communication,machine learning,artificial intelligence(AI),and deep learning shows promise in addressing these challenges.However,there is a lack of comprehensive documentation on the application and potential of AI in improving agricultural input efficiency.To address this gap,a desk research approach was used by utilizing peer-reviewed electronic databases like PubMed,Scopus,Goo-gle Scholar,Web of Science,and Science Direct for relevant articles.Out of 327 initially identified articles,180 were deemed pertinent,focusing primarily on AI’s potential in enhancing yield through better management of nutrients,water,and weeds.Taking into account researchfindings worldwide,we found that AI technologies could assist farmers by providing recommendations on the optimal nutrients to enhance soil quality and deter-mine the best time for irrigation or herbicide application.The present status of AI-driven automation in agricul-ture holds significant promise for optimizing agricultural input utilization and reducing resource waste,particularly in the context of three pillars of crop management,i.e.,nutrient,irrigation,and weed management.

高级别管线用焊丝EF3超低磷冶炼工艺实践

为实现高级别管线用超低P焊丝EF3的批量稳定生产,对脱P的热力学条件和动力学条件研究,明确脱P的条件。通过铁水脱P、100 t转炉脱P、钢包脱P配合扒渣、二次LF精炼防回P工艺,配合低P合金,实现了超低P焊丝EF3的稳定生产。控制铁水w[Si]≤0.15%,造高碱度(R=6)的炉渣,可同时脱P、脱S,实现铁水w[P]≤0.020%、铁水w[S]≤0.005%;转炉终点温度在1595~1610℃,终渣碱度4.0左右,终渣中w[FeO]在23.0%~26.0%,可实现转炉出钢w[P]≤0.008%;采用钢包脱P,可实现钢水w[P]≤0.004%;钢包脱磷后配合扒渣工艺,扒渣前后基本不回P,采用二次LF精炼防增P,配合低P合金,增P量极少;从而可实现中间包钢水w[P]≤0.005%。

基于EFE和IFE矩阵模型的永川茶产业发展策略

茶文化是我国重要的传统文化,促进茶产业发展是乡村振兴的重要工作内容。文章以重庆市永川区为例,通过EFE与IFE矩阵模型探索影响当地茶产业发展的关键因素,进而提出乡村振兴视角下适用于该地区的茶产业发展与提升策略。

2017-08-11内蒙赤峰EF4级山地多发龙卷灾调与成因分析

2017年8月11日下午,三个EF4级龙卷袭击了内蒙古自治区赤峰市的地形复杂地区,造成5人死亡,58人受伤。这是1961年以来中国有记录的最强山地龙卷事件。首先给出了此次龙卷过程的灾情调查结果,接下来分析了此次龙卷母体风暴-龙卷超级单体产生的天气背景、关键环境参数以及多普勒天气雷达观测特征。本次龙卷事件发生在东北冷涡东南象限的地面锋前和干线向湿侧发展处,CAPE(对流有效位能)值为1800 J/kg,0~6 km风垂直切变为12.9 m/s,0~1 km风垂直切变达到10.8 m/s;同时,0~1 km相对风暴螺旋度达到67.3 m^(2)/s^(2),接近美国龙卷发生环境的中位数,有利于超级单体龙卷的发生。现场灾害调查发现,灾害路径具有多涡旋和不连续的特点,可能与当地的复杂地形有关。基于多普勒天气雷达相对径向速度图识别出三个龙卷涡旋特征(TVS),TVS径向速度差最大达到38 m/s。三个龙卷及对应TVS出自同一个超级单体的同一个中气旋,其中两个TVS出现时间重叠。

基于EF-1α和β微管蛋白基因序列的棉花枯萎病菌遗传多样性和单倍型分析

【目的】通过分析棉花枯萎病菌的遗传多样性,探究新疆棉花枯萎病菌株的分群及其演化。【方法】2022年在新疆不同植棉区共分离出22株棉花枯萎病菌株,对延伸因子1α(elongation factor-1α,EF-1α)和β微管蛋白基因进行扩增、测序,并从美国国立生物技术信息中心(National Center for Biotechnology Information,NCBI)数据库获取36个棉花枯萎病菌株的相关基因序列信息。基于上述基因序列分别进行系统进化分析和单倍型分析。【结果】基于57条EF-1α基因序列的进化树分析表明,棉花枯萎病菌可分为3大群,第1大群包含来自新疆、河北和澳大利亚的共31个枯萎病菌株,该大群可分成4个亚群;第2大群包含25个枯萎病菌株,构成比较复杂,可分成3个亚群;第3大群仅包含美国菌株LA140。基于28条β微管蛋白基因序列的进化树分析表明,本次分离的新疆棉花枯萎病菌株与棉花枯萎病菌7号和8号生理小种不同。根据EF-1α基因序列构建的单倍型网络将棉花枯萎病菌株分为19个单倍型,新疆21个棉花枯萎病菌株归属于有共同起源的5种单倍型。【结论】本研究分离的新疆棉花枯萎病菌株与已报道的棉花枯萎病菌1~8号生理小种均不相同,但与河北菌株的亲缘关系较近。EF-1α单倍型分析表明,本研究中的所有棉花枯萎病菌均从1号生理小种演化而来。

N-doped carbon-coated Fe_(3)N composite as heterogeneous electro-Fenton catalyst for efficient degradation of organics

Herein,the application of a N-doped graphitic-carbon-coated iron nitride composite dispersed in a N-doped carbon framework(Fe_(3)N@NG/NC)is investigated as a heterogeneous electro-Fenton(HE-EF)catalyst for the efficient removal of organics.The simultaneous carbonization and ammonia etching of iron-based metal organic framework(Fe-MOF)materials yielded well-dispersed N-doped carbon-coated Fe_(3)N nanoparticles with a diameter of~70 nm.The Fe_(3)N and pyridinic N endowed the composite with high HE-EF activity for decomposing the electrogenerated H_(2)O_(2) to•OH.The Fe_(3)N@NG/NC exhibited outstanding HE-EF performance in removing various organic pollutants with low iron leaching.A removal rate of 97-100%could be obtained for rhodamine B(RhB),dimethyl phthalate,methylene blue,and orange Ⅱ in 120 min at a pH of 5.0.When the solution pH was set to 3.0,5.0,7.0,and 9.0,the removal rate of RhB reached 100%,96%,92%,and 81%,respectively,in 60 min at an optimum voltage of 0.0 V(vs.reversible hydrogen electrode(RHE)).Moreover,the concentration of leached iron was expected to be below 0.03 mg/L in a wide pH range of 3.0-9.0.In addition,the RhB removal efficiency remained as high as 90%after six cycles in the reusability experiments.This work highlights the MOF-derived Fe_(3)N composite as an efficient HE-EF catalyst and the corresponding catalytic mechanism,which facilitates its application in wastewater treatment.

Review of preferentially selective lithium extraction from spent lithium batteries: Principle and performance

Lithium,as the lightest and lowest potential metal,is an ideal "battery metal" and the core strategic metal of the new energy industry revolution.Recovering lithium from spent lithium batteries(LIBs)has become one of the significant approaches to obtaining lithium resources.At present,the lithium extraction being generally placed at the last step of the spent LIBs recovery process has puzzles such as high acid consumption,low Li recovery purity and low recovery efficiency.Selective lithium extraction at the first step of the recovery process can effectively solve those puzzles.Since lithium leaching is a non-spontaneous reaction requiring additional energy to achieve,it is found that these methods can be divided into five ways according to the different types of energy driving the reaction occurring:(ⅰ)electric energy driving lithium extraction;(ⅱ) chemical energy driving lithium extraction;(ⅲ) mechanical energy driving lithium extraction;(ⅳ) thermal energy driving lithium extraction;(ⅴ) other energy driving lithium extraction.Through the analysis of the principle,reaction process and results of recovering lithium methods can provide a few directions for scholars’ subsequent research.It is necessary to speed up the exploration of the principle of these methods.It is expected that this study could provide a reference for the research on the selective lithium extraction.

一种基于EF和CIFF的10 bit二阶噪声整形SAR ADC

设计了一种10 bit阶噪声整形的逐次逼近型模数转换器(NS-SAR ADC)。为了减小高精度SAR ADC中量化噪声的影响,该NS-SAR ADC采用了级联积分器前馈(CIFF)与误差反馈(EF)相结合的噪声整形方案。其中EF路径采用低增益动态放大器构成的无损积分架构,CIFF路径采用电压倍增的无源整形架构。它结合了CIFF与EF两种噪声整形架构的优点,具有更好的鲁棒性。电路采用TSMC 65 nm CMOS工艺设计,在电源电压为1.2 V、输入信号幅度为1 V、采样率为25 MHz的条件下,SNDR达到77.91 dB,带宽BW为1.5625 MHz,功耗为465μW。

南酸枣多糖的体外抗氧化、降血糖与降血脂作用

以南酸枣多糖体积分数40%乙醇沉淀组分CAP-40为研究对象,初步评价其体外抗氧化、降血糖与降血脂作用。分别利用高效液相凝胶渗透色谱及高效液相离子色谱测定CAP-40的分子量与单糖组成,同时测定其对DPPH·和ABTS+·的清除率,α-葡萄糖苷酶和α-淀粉酶的抑制率,甘氨胆酸钠和牛磺胆酸钠的结合率以及胰脂肪酶的抑制率。结果表明,CAP-40的洗脱曲线为单一对称峰,分子量约156206 Da,单糖主要由葡萄糖、半乳糖醛酸、半乳糖、阿拉伯糖、鼠李糖组成,摩尔百分比分别为40.8%、40.7%、9.3%、5.1%、2.0%。CAP-40浓度为1 mg/mL时,对DPPH·和ABTS^(+)·的清除率分别为(88.85±0.49)%和(87.13±1.63)%。浓度为16 mg/mL时,CAP-40对α-葡萄糖苷酶的抑制率为(71.28±2.34)%;在8 mg/mL处,对α-淀粉酶的抑制率为(72.29±4.85)%。此外,浓度为20 mg/mL时,CAP-40对胰脂肪酶的抑制率为(26.34±1.41)%;在5 mg/mL处,对甘氨胆酸钠和牛磺胆酸钠的结合率分别达到(31.87±4.53)%和(38.98±0.60)%。综上所述,南酸枣多糖CAP-40具有一定的体外抗氧化、降血糖与降血脂作用,为开发天然降糖、降脂功能食品提供理论依据,也为南酸枣资源的综合开发利用提供新的思路。

Investigating the Effects of Eichhornia Crassipes Biodiesel and Liquefied Petroleum Gas on the Performance and Emissions of a Dual-Fuel Engine

This study considers the effect of Eichhornia Crassipes Biodiesel(ECB)blends on the performances,combustion,and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode(DFM)and equipped with an Exhaust gas recirculation technique(EGR).In particular,a single-cylinder,four-stroke,water-cooled diesel engine was utilized and four modes of fuel operation were considered:mode I,the engine operated with an ordinary diesel fuel;mode II,the engine operated with the addition of 2.4 L/min of lique-fied petroleum gas(LPG)and 20%EGR;mode III,20%ECB with 2.4 L/min LPG and 20%EGR;mode IV,40%ECB with 2.4 L/min LPG and 20%EGR.The operation conditions were constant engine speed(1500 rpm),var-iation of load(25%,50%,75%,and 100%),full load,with a compression ratio of 18,and a time injection of 23°BTDC(Before top died center).With regard to engine emissions,carbon dioxide(CO_(2)),carbon monoxide(CO),hydrocarbons(UHC),and nitrogen oxide(NOX)were measured using a gas analyzer.The smoke opacity was measured using an OPABOX smoke meter.By comparing the results related to the different modes with mode I at full load,the BTE(Brake thermal efficiency)increased by 20.17%,11.45%,and 12.66%with modes II,III,and IV,respectively.In comparison to the results for mode II,the BTE decreased due to the combustion of ECB blends by 7.26%and 6.24%for mode III and mode IV,respectively,at full load.In comparison to mode II,the Brake specific energy consumption(BSEC)increased with the ECB substitution.With ECB blends,there is a noticeable decrease in the CO,CO_(2),and UHC emissions at a partial load.Furthermore,the 20%ECB has no effect on CO emissions at full load.For modes II and IV,the CO_(2)increased by 33.33%and 19%,respectively,while the UHC emissions were reduced by 14.49%for mode III and 26.08%for mode IV.The smoke of mode III was lower by 7.21%,but for mode IV,it was higher by 12.37%.In addition,with mode III and mode IV,the NOx emissions increased by 30.50%and 18.80%,respectively.

Energy Efficient Networks Using Ant Colony Optimization with Game Theory Clustering

Real-time applications based on Wireless Sensor Network(WSN)tech-nologies quickly lead to the growth of an intelligent environment.Sensor nodes play an essential role in distributing information from networking and its transfer to the sinks.The ability of dynamical technologies and related techniques to be aided by data collection and analysis across the Internet of Things(IoT)network is widely recognized.Sensor nodes are low-power devices with low power devices,storage,and quantitative processing capabilities.The existing system uses the Artificial Immune System-Particle Swarm Optimization method to mini-mize the energy and improve the network’s lifespan.In the proposed system,a hybrid Energy Efficient and Reliable Ant Colony Optimization(ACO)based on the Routing protocol(E-RARP)and game theory-based energy-efficient clus-tering algorithm(GEC)were used.E-RARP is a new Energy Efficient,and Reli-able ACO-based Routing Protocol for Wireless Sensor Networks.The suggested protocol provides communications dependability and high-quality channels of communication to improve energy.For wireless sensor networks,a game theo-ry-based energy-efficient clustering technique(GEC)is used,in which each sen-sor node is treated as a player on the team.The sensor node can choose beneficial methods for itself,determined by the length of idle playback time in the active phase,and then decide whether or not to rest.The proposed E-RARP-GEC improves the network’s lifetime and data transmission;it also takes a minimum amount of energy compared with the existing algorithms.

Cluster Head Selection and Multipath Routing Based Energy Efficient Wireless Sensor Network

The Wireless Sensor Network(WSN)is a network of Sensor Nodes(SN)which adopt radio signals for communication amongst themselves.There is an increase in the prominence of WSN adaptability to emerging applications like the Internet of Things(IoT)and Cyber-Physical Systems(CPS).Data secur-ity,detection of faults,management of energy,collection and distribution of data,network protocol,network coverage,mobility of nodes,and network heterogene-ity are some of the issues confronted by WSNs.There is not much published information on issues related to node mobility and management of energy at the time of aggregation of data.Towards the goal of boosting the mobility-based WSNs’network performance and energy,data aggregation protocols such as the presently-used Mobility Low-Energy Adaptive Clustering Hierarchy(LEACH-M)and Energy Efficient Heterogeneous Clustered(EEHC)scheme have been exam-ined in this work.A novel Artificial Bee Colony(ABC)algorithm is proposed in this work for effective election of CHs and multipath routing in WSNs so as to enable effective data transfer to the Base Station(BS)with least energy utilization.There is avoidance of the local optima problem at the time of solution space search in this proposed technique.Experimentations have been conducted on a large WSN network that has issues with mobility of nodes.

产融结合的同群效应研究——来自A股上市公司的经验证据

已有关于产融结合的研究较少从同群效应视角考察。本文基于中国沪、深两市A股2008—2020年非平衡面板数据,重点探究产融结合同群效应的存在合理性、产生机制及可能造成的经济后果。研究发现,产融结合分别在深度和广度两方面存在显著的同群效应,采用同群企业股票特质收益率作为工具变量及多项稳健性检验,结果依然成立。领导企业的产融结合同群效应表现为“竞争动机”,追随企业的产融结合同群效应是出于“信息动机”。产融结合同群效应能够降低企业面临的风险,但是会提高社会层面的整体风险水平。本研究拓展了同群效应及产融结合影响因素的研究边界,为政府部门完善有关经济政策、企业制定产融结合决策提供了理论依据与经验证据。

德国和西班牙对EFSA草甘膦裁决存在分歧

草甘膦是一种有争议但在欧盟使用最广泛的除草剂,7月初,欧盟食品安全局(EFSA)公布了其期待已久的草甘膦风险评估的主要结论。根据该机构的说法,当涉及到在植物保护中使用这种物质的潜在有害影响时,没有发现“严重关切的领域”。虽然该机构的评估是决定2023年12月以后欧盟范围内重新批准草甘膦的关键一步,但在如何看待EFSA的结论方面,并不是所有欧盟国家都持相同立场。

基于语段理论的存现句的核心结构与生成

基于在Chomsky近期所提出的“语段理论”尝试探讨自然语言中的存现句的生成机制。论证存现句的核心结构是一个以表“存在”义的功能语类轻动词Ex的投射。该轻动词Ex缺少外论元,因而不是语段。研究还发现,Ex的边缘特征EF在不同语言中呈现参数化差异,可以以此解释英汉存现结构之间的差异。

Ce(NO_(3))_(3)和CeO_(2)纳米粒子对APTES膜耐腐蚀性的影响

目的通过对铜箔进行硅烷化处理,增强铜箔的耐腐蚀性能。方法采用化学浸泡法在9μm电解铜箔表面制备γ-氨丙基三乙氧基硅烷偶联剂(APTES)硅烷膜层、Ce^(3+)/APTES膜层、CeO_(2)/APTES膜层和Ce^(3+)/CeO_(2)/APTES膜层,对改性硅烷膜试样与空白试样进行接触角对照实验,对硅烷表面润湿性进行表征。在3.5%(质量分数)NaCl溶液中,对空白样、单一硅烷膜层、Ce^(3+)/APTES硅烷膜层和Ce^(3+)/CeO_(2)/APTES硅烷膜层进行浸泡实验和电化学实验,研究改性膜层前后的耐腐蚀性能。通过扫描电子显微镜(SEM)观察膜层表面形貌,并利用傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)对纳米粒子结构进行分析,探讨改性膜层的钝化机理。结果Ce(NO_(3))_(3)/CeO_(2)/APTES复合膜层的接触角最大,接触角为106.6°,表现出最佳的疏水性。同时,其表面的腐蚀坑数量和面积最小。在盐水浸泡和电化学实验中,各试样的腐蚀电流密度随着浸泡时间的延长而上升,Ce^(3+)/CeO_(2)/APTES试样的腐蚀电位发生正移,具有较低的腐蚀电流密度,并且该试样具有最高的相角和最高的阻抗值,远高于Ce^(3+)/APTES试样。结论与单一硅烷膜层和仅分别添加Ce(NO_(3))_(3)、CeO_(2)2种缓蚀剂的膜层相比,Ce(NO_(3))_(3)/CeO_(2)/APTES复合膜层的防护效果有明显提升,且Ce^(3+)与CeO_(2)之间的协同作用大大提高了硅烷膜层的耐腐蚀性能。