Current optimization-based control of dual three-phase PMSM for low-frequency temperature swing reduction

In this paper,a control scheme based on current optimization is proposed for dual three-phase permanent-magnet synchronous motor(DTP-PMSM)drive to reduce the low-frequency temperature swing.The reduction of temperature swing can be equivalent to reducing maximum instantaneous phase copper loss in this paper.First,a two-level optimization aiming at minimizing maximum instantaneous phase copper loss at each electrical angle is proposed.Then,the optimization is transformed to a singlelevel optimization by introducing the auxiliary variable for easy solving.Considering that singleobjective optimization trades a great total copper loss for a small reduction of maximum phase copper loss,the optimization considering both instantaneous total copper loss and maximum phase copper loss is proposed,which has the same performance of temperature swing reduction but with lower total loss.In this way,the proposed control scheme can reduce maximum junction temperature by 11%.Both simulation and experimental results are presented to prove the effectiveness and superiority of the proposed control scheme for low-frequency temperature swing reduction.

TRIP980钢的组织性能调控与动态本构模型

设计了一种相变诱导塑性(TRIP)钢,研究了贝氏体等温温度对力学性能和微观组织的影响。针对最优工艺,研究了10^(-4)~10^(3) s^(-1)应变速率范围内的动态力学性能,构建并修正了动态本构数学模型。结果表明:当贝氏体等温温度为380℃时,实验钢具有最优的静态力学性能(应变速率10^(-3)s^(-1)),屈服强度达到705 MPa,抗拉强度达到1005 MPa,伸长率为16%,强塑积达到了1.6 GPa·%。应变速率的变化对实验钢的硬化行为和TRIP效应的发生有明显的影响。当应变速率达到10^(3) s^(-1)时,屈服强度和抗拉强度分别达到了815和1145 MPa,分别提高了12.4%和13.9%。经A4系数修正后的动态本构数学模型表明,R值和eAARE的平均值分别达到0.9895和27.5%,具有较精确的预测精度。

Deciphering engineering principle of three-phase interface for advanced gas-involved electrochemical reactions

As an alternative to conventional energy conversion and storage reactions,gas-involved electrochemical reactions,including the carbon dioxide reduction reaction(CO_(2)RR),nitrogen reduction reaction(NRR)and hydrogen evolution reaction(HER),have become an emerging research direction and have gained increasing attention due to their advantages of environmental friendliness and sustainability.Various studies have been designed to accelerate sluggish kinetics but with limited results.Most of them promote the reaction by modulating the intrinsic properties of the catalyst,ignoring the synergistic effect of the reaction as a whole.Due to the introduction of gas,traditional liquid-solid two-phase reactions are no longer applicable to future research.Since gas-involved electrochemical reactions mostly occur at the junctions of gaseous reactants,liquid electrolytes and solid catalysts,the focus of future research on reaction kinetics should gradually shift to three-phase reaction interfaces.In this review,we briefly introduce the formation and constraints of the three-phase interface and propose three criteria to judge its merit,namely,the active site,mass diffusion and electron mass transfer.Subsequently,a series of modulation methods and relevant works are discussed in detail from the three improvement directions of‘exposing more active sites,promoting mass diffusion and accelerating electron transfer’.Definitively,we provide farsighted insights into the understanding and research of three-phase interfaces in the future and point out the possible development direction of future regulatory methods,hoping that this review can broaden the future applications of the three-phase interface,including but not limited to gas-involved electrochemical reactions.

Electrical characteristics of new three-phase traction power supply system for rail transit

A novel three-phase traction power supply system is proposed to eliminate the adverse effects caused by electric phase separation in catenary and accomplish a unifying manner of traction power supply for rail transit.With the application of two-stage three-phase continuous power supply structure,the electrical characteristics exhibit new features differing from the existing traction system.In this work,the principle for voltage levels determining two-stage network is dissected in accordance with the requirements of traction network and electric locomotive.The equivalent model of three-phase traction system is built for deducing the formula of current distribution and voltage losses.Based on the chain network model of the traction network,a simulation model is established to analyze the electrical characteristics such as traction current distribution,voltage losses,system equivalent impedance,voltage distribution,voltage unbalance and regenerative energy utilization.In a few words,quite a lot traction current of about 99%is undertaken by long-section cable network.The proportion of system voltage losses is small attributed to the two-stage three-phase power supply structure,and the voltage unbal-ance caused by impedance asymmetry of traction network is less than 1‰.In addition,the utilization rate of regenerative energy for locomotive achieves a significant promotion of over 97%.

Speed Regulation Method Using Genetic Algorithm for Dual Three-phase Permanent Magnet Synchronous Motors

Dual three-phase Permanent Magnet Synchronous Motor(DTP-PMSM)is a nonlinear,strongly coupled,high-order multivariable system.In today’s application scenarios,it is difficult for traditional PI controllers to meet the requirements of fast response,high accuracy and good robustness.In order to improve the performance of DTP-PMSM speed regulation system,a control strategy of PI controller based on genetic algorithm is proposed.Firstly,the basic mathematical model of DTP-PMSM is established,and the PI parameters of DTP-PMSM speed regulation system are optimized by genetic algorithm,and the modeling and simulation experiments of DTP-PMSM control system are carried out by MATLAB/SIMULINK.The simulation results show that,compared with the traditional PI control,the proposed algorithm significantly improves the performance of the control system,and the speed output overshoot of the GA-PI speed control system is smaller.The anti-interference ability is stronger,and the torque and double three-phase current output fluctuations are smaller.

TRIP13通过同源重组通路提高肺腺癌细胞的放射抗性

背景与目的放疗是非小细胞肺癌(non-small cell lung cancer,NSCLC)最常用的治疗手段之一。然而,一部分肿瘤细胞对放射线的不敏感是放疗疗效差、患者预后不良的重要原因之一,探究放射抵抗背后的深层机制是解决这一临床难题的关键。本研究旨在寻找与肺腺癌(lungadenocarcinoma,LUAD)放射抵抗相关的分子,初步经数据库筛选锁定甲状腺素受体结合因子13(thyroid hormone receptor interactor 13,TRIP13)为主要研究对象,并探索TRIP13是否与LUAD的放射抵抗有关及具体机制,以期为临床接受放疗的LUAD患者的联合治疗提供理论依据和潜在靶点。方法选取基因表达综合数据库(Gene Expression Omnibus,GEO)中的GSE18842、GSE19188和GSE33532共3个数据集,借助R 4.1.3软件分别筛选3个数据集中差异表达的基因(|logFC|>1.5,P<0.05),之后使用Venn diagram找出在3个数据集中共有的差异表达基因。随后,借助STRING在线工具和Cytoscape软件,对筛选出来的差异基因进行蛋白质相互作用分析和模块分析,借助Kaplan-Meier Plotter数据库对各基因进行生存预后分析,并确定TRIP13基因作为后续主要研究分子。随后,采用亚致死性剂量照射法对人LUAD细胞系H292进行多次X射线照射,以构建具有放射抗性的细胞系H292DR。采用细胞计数试剂盒-8(cell counting kit-8,CCK-8)实验和克隆形成实验验证H292DR细胞的放射抗性能力。Western blot检测H292细胞和H292DR细胞中TRIP13蛋白的表达水平。使用小干扰RNA(small interfering RNA,siRNA)沉默H292DR细胞中TRIP 13蛋白的表达并进行Western blot检测。观察TRIP13沉默后H292DR细胞的克隆形成能力和迁移能力,随后检测共济失调-毛细血管扩张突变(ataxia telangiectasia mutated,ATM)蛋白等与同源重组密切相关的蛋白的表达水平变化。结果经多个GEO数据集筛选、外部数据集的验证以及生存分析发现,TRIP13在LUAD中高表达,并与接受过放疗的LUAD患者的不良预后有关;并且,TRIP13基因富集分析(gene set enrichment analysis,GSEA)的结果提示,TRIP13可能通过促进放疗后的同源重组修复而与LUAD放射抵抗有密切关联。经实验检测发现,TRIP13的表达在H292DR中上调,而沉默TRIP13后能够增加H292DR细胞对放射线的敏感性。结论TRIP13与接受放疗后的LUAD患者的预后不良有关,可能是通过促进同源重组修复途径来介导LUAD细胞对放射线的抵抗。

Optimization of Control Loops and Operating Parameters for Three-Phase Separators Used in Oilfield Central Processing Facilities

In this study,the Stokes formula is used to analyze the separation effect of three-phase separators used in a Oilfield Central Processing Facility.The considered main influencing factors include(but are not limited to)the typical size of oil and water droplets,the residence time and temperature of fluid and the dosage of demulsifier.Using the“Specification for Oil and Gas Separators”as a basis,the control loops and operating parameters of each separator are optimized Considering the Halfaya Oilfield as a testbed,it is shown that the proposed approach can lead to good results in the production stage.

Purification of Moringa oleifera Leaves Protease by Three-Phase Partitioning and Investigation of Its Potential Antibacterial Activity

One of plant-based products for dental care is plant-based proteolytic enzymes which are principally proteases. In order not to damage the protein and bioactive content, an efficient method should be employed for their purifications. As such, three-phase partitioning (TPP) was used to purify protease from moringa (Moringa oleifera). TPP is an emerging, promising, non-chromatographic and economical technology which is simple, quick, efficient and often one-step process for the separation and purification of bioactive molecules from natural sources. It involves the addition of salt (ammonium sulphate) to the crude extract followed by the addition of an organic solvent (butanol). The protein appears as an interfacial precipitate between upper organic solvent and lower aqueous phases. The various conditions such as ammonium sulphate, ratio of crude extract to t-butanol and pH which are required for attaining efficient purification of the protease fractions were optimized. Under optimized conditions, it was seen that, 35% of ammonium sulphate saturation with 1:0.75 ratio of crude extract to t-butanol at pH 7 gave 4.94-fold purification with 96.20% activity yield of protease in the middle phase of the TPP system. The purified enzyme from Moringa oleifera has no antimicrobial effect on the pathogenic bacteria tested. However, this purified enzyme, can be considered as a promising agent, cheap, and safe source which is suitable for using in various industries.

Vibration characteristics of sandwich plates with an auxetic honeycomb core and laminated three-phase skin layers under blast load

In this article,vibration characteristics of sandwich plates with an auxetic honeycomb core and laminated three-phase skin layers subjected to blast load are studied.Higher-order ES-MITC3 element based on higher-order shear deformation theory(HSDT)to achieve the governing equations.The sandwich plates with the ultra-light feature of the auxetic honeycomb core layer(negative Poisson’s ratio)and reinforced by two laminated three-phase skin layers.The obtained results in our work are compared with other previously published to confirm accuracy and reliability.In addition,the effects of parameters such as geometrical and material parameters on the vibration characteristics of sandwich plates with an auxetic honeycomb core and laminated three-phase skin layers are fully investigated.

Enhancing ammonia production rates from electrochemical nitrogen reduction by engineering three-phase boundary with phosphorus-activated Cu catalysts

Electrochemical N_(2) reduction reaction(eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N_(2) molecules and the limited supply of N_(2) to the catalyst due to its low solubility in aqueous electrolytes.Herein,we propose phosphorus-activated Cu electrocatalysts to generate electron-deficient Cu sites on the catalyst surface to promote the adsorption of N_(2) molecules.The eNRR system is further modified using a gas diffusion electrode(GDE) coated with polytetrafluoroethylene(PTFE) to form an effective three-phase boundary of liquid water-gas N_(2)-solid catalyst to facilitate easy access of N_(2) to the catalytic sites.As a result,the new catalyst in the flow-type cell records a Faradaic efficiency of 13.15% and an NH_(3) production rate of 7.69 μg h^(-1) cm^(-2) at-0.2 V_(RHE),which represent 3.56 and 59.2 times increases from those obtained with a pristine Cu electrode in a typical electrolytic cell.This work represents a successful demonstration of dual modification strategies;catalyst modification and N_(2) supplying system engineering,and the results would provide a useful platform for further developments of electrocatalysts and reaction systems.

Automatic measurement of three-phase contact angles in pore throats based on digital images

With the help of digital image processing technology, an automatic measurement method for the three-phase contact angles in the pore throats of the microfluidic model was established using the microfluidic water flooding experiment videos as the data source. The results of the new method were verified through comparing with the manual measurement data.On this basis, the dynamic changes of the three-phase contact angles under flow conditions were clarified by the contact angles probability density curve and mean value change curve. The results show that, for water-wetting rocks, the mean value of the contact angles is acute angle during the early stage of the water flooding process, and it increases with the displacement time and becomes obtuse angle in the middle-late stage of displacement as the dominant force of oil phase gradually changes from viscous force to capillary force. The droplet flow in the remaining oil occurs in the central part of the pore throats, without three-phase contact angle. The contact angles for the porous flow and the columnar flow change slightly during the displacement and present as obtuse angles in view of mean values, which makes the remaining oil poorly movable and thus hard to be recovered. The mean value of the contact angle for the cluster flow tends to increase in the flooding process, which makes the remaining oil more difficult to be recovered. The contact angles for the membrane flow are mainly obtuse angles and reach the highest mean value in the late stage of displacement, which makes the remaining oil most difficult to be recovered. After displacement, the remaining oils under different flow regimes are just subjected to capillary force, with obtuse contact angles, and the wettability of the pore throat walls in the microfluidic model tends to be oil-wet under the action of crude oil.

Application of CD34 expression combined with three-phase dynamic contrast-enhanced computed tomography scanning in preoperative staging of gastric cancer

BACKGROUND Accurate preoperative staging of gastric cancer(GC),a common malignant tumor worldwide,is critical for appropriate treatment plans and prognosis.Dynamic three-phase enhanced computed tomography(CT)scanning for preoperative staging of GC has limitations in evaluating tumor angiogenesis.CD34,a marker on vascular endothelial cell surfaces,is promising in evaluating tumor angiogenesis.We explored the value of their combination for preoperative staging of GC to improve the efficacy and prognosis of patients with GC.Medical records of 106 patients with GC treated at the First People's Hospital of Lianyungang between February 2021 and January 2023 were retrospectively studied.All patients underwent three-phase dynamic contrast-enhanced CT scanning before surgery,and CD34 was detected in gastroscopic biopsy specimens.Using surgical and pathological results as the gold standard,the diagnostic results of three-phase dynamic contrast-enhanced CT scanning at different T and N stages were analyzed,and the expression of CD34-marked microvessel density(MVD)at different T and N stages was determined.The specificity and sensitivity of three-phase dynamic contrast-enhanced CT and CD34 in T and N staging were calculated;those of the combined diagnosis of the two were evaluated in parallel.Independent factors affecting lymph node metastasis were analyzed using multiple logistic regression.RESULTS The accuracy of three-phase dynamic contrast-enhanced CT scanning in diagnosing stages T1,T2,T3 and T4 were 68.00%,75.00%,79.41%,and 73.68%,respectively,and for diagnosing stages N0,N1,N2,and N3 were 75.68%,74.07%,85.00%,and 77.27%,respectively.CD34-marked MVD expression increased with increasing T and N stages.Specificity and sensitivity of three-phase dynamic contrast-enhanced CT in T staging were 86.79%and 88.68%;for N staging,89.06%and 92.86%;for CD34 in T staging,64.15%and 88.68%;and for CD34 in N staging,84.38%and 78.57%,respectively.Specificity and sensitivity of joint diagnosis in T staging were 55.68%and 98.72%,and N staging were 75.15%and 98.47%,respectively,with the area under the curve for diagnosis improving accordingly.According to multivariate analysis,a longer tumor diameter,higher pathological T stage,lower differ-entiation degree,and higher expression of CD34-marked MVD were independent risk factors for lymph node metastasis in patients with GC.CONCLUSION With high accuracy in preoperatively determining the invasion depth and lymph node metastasis of GC,CD34 expression and three-phase dynamic contrast-enhanced CT can provide a reliable basis for surgical resection.

基于TRIP效应的复相钢的组织特征及强塑性机制

采用扫描电镜(SEM)、电子背散射衍射(EBSD)技术和透射电镜(TEM)对复相钢的微观形貌进行表征,并研究了其基于相变诱导塑性(TRIP)效应的强塑性机制。结果表明,将退火温度设定在单相奥氏体区和(γ+α)两相临界区,由于微观形貌特征的不同致使试验钢的力学性能有着显著的区别。退火温度(915℃)在单相奥氏体区时,微观组织由27%先共析铁素体、56%块状贝氏体以及分布于晶界处的17%残留奥氏体组成;组织中的先共析铁素体,其塑性优于再结晶铁素体,更有利于发挥协调变形作用,通过缓解应力对残留奥氏体的作用而有效发挥其TRIP效应;同时均匀分布于晶界处纵横比>2.0的块状残留奥氏体,在变形过程中由于受到相界面及块状硬质相贝氏体的阻碍,TRIP效应的贡献较大且可在整个应变阶段持续地发生。在晶粒尺寸、组织形貌、晶体学结构、V(C,N)析出和位错塞积,以及TRIP效应的共同作用下,915℃退火后复相钢的综合力学性能最优,屈服强度和抗拉强度分别为756和1135 MPa,强塑积可达到26.446 GPa·%,同时具有优良的伸长率和扩孔性能,分别为23.3%和56%。

Microstructure and mechanical properties of a cast TRIP-assisted multiphase stainless steel

Stainless steels are used in a wide range of complex environments due to their excellent corrosion resistance.Multiphase stainless steels can offer an excellent combination of strength,toughness and corrosion resistance due to the coexistence of different microstructures.The microstructure and mechanical properties of a novel cast multiphase stainless steel,composed of martensite,ferrite,and austenite,were investigated following appropriate heat treatment processes:solution treatment at 1,050℃ for 0.5 h followed by water quenching to room temperature,and aging treatment at 500℃ for 4 h followed by water quenching to room temperature.Results show reversed austenite is formed by diffusion of Ni element during aging process,and the enrichment of Ni atoms directly determines the mechanical stability of austenite.The austenite with a lower Ni content undergoes a martensitic transformation during plastic deformation.The tensile strength of the specimen exceeds 1,100 MPa and the elongation exceeds 24%after solid solution,and further increases to 1,247 MPa and 25%after aging treatment.This enhancement is due to the TRIP effect of austenite and the precipitation of the nanoscale G-phase pinning dislocations in ferrite and martensite.

TRIP13促进子宫内膜癌增殖、迁移和侵袭的影响及作用机制

目的:探讨甲状腺激素受体因子13(Thyroid hormone receptor interactor 13,TRIP13)对子宫内膜癌(Endometrial carcinoma,EC)增殖、迁移和侵袭的影响及调控机制。方法:分析TRIP13在子宫内膜癌中的表达模式;通过慢病毒敲减和质粒过表达调控子宫内膜癌细胞中TRIP13的表达量;通过CCK-8、Transwell迁移及侵袭实验观察TRIP13对子宫内膜癌细胞增殖、迁移及侵袭能力的影响;通过Western blot技术检测TRIP13表达水平的变化,并研究其对PI3K/Akt信号通路蛋白的影响。结果:癌症基因组图谱(The Cancer Genome Atlas,TCGA)分析发现,子宫内膜癌组织中TRIP13的表达水平显著高于正常子宫内膜组织(P<0.05);TRIP13的高表达与子宫内膜癌患者的低生存率呈显著正相关(P<0.05)。TRIP13过表达可促进子宫内膜癌细胞的增殖、迁移及侵袭能力(P<0.05),并上调p-PI3K、p-Akt的表达(P<0.05),而下调TRIP13后则可逆转上述结果。结论:TRIP13通过调控PI3K/Akt信号通路促进子宫内膜癌细胞的增殖、迁移和侵袭。

从TRIPS到CPTPP:著作权国际保护标准的提高及对中国的启示

随着后TRIPS时代的到来,TRIPS所建立的著作权国际保护体系显得难以适应快速发展的经济与科技环境。因此,各国开始以自由贸易协定的模式探索著作权国际保护新标准,比如签订CPTPP。文章通过对CPTPP与TRIPS文本的研究对比,认为CPTPP著作权国际保护标准较TRIPS有了大幅提升,扩大了复制权、向公众传播权的保护范围和权利主体范围,延长了权利保护期限,缩减了著作权的限制与例外空间,增加了损害赔偿数额,加强了执法力度和知识产权救济措施。2021年,我国正式申请加入CPTPP,为能顺利对接国际著作权保护规则,文章具体分析了国内著作权法律制度与国际规则的差异,并提出了应对之策。

TRIPS-Plus扩张背景下发展中国家知识产权国际保护的因应策略

TRIPS-Plus扩张消减了针对发展中国家的弹性条款和差别待遇,加重了发展中国家的知识产权实施成本,侵蚀了发展中国家争取的知识产权国际规则变革成果。包括中国在内的发展中国家应当从“随势而动”到“谋势而为”,主动成为知识产权国际规则的制定者。借鉴发达国家体制转换策略,探索自贸协定内知识产权保护的新体例。一方面,重视“南南联合”,构建新型TRIPS-Plus规则,保护发展中国家的传统资源;另一方面,正视“南北博弈”,积极设置鼓励性条款,协调南北矛盾,重构知识产权国际保护新规则,推动知识产权国际规则向更加公正合理的方向发展。

CPTPP超TRIPS边境措施的新挑战与应对——基于发展中国家的视角

CPTPP知识产权超TRIPS边境措施减损了TRIPS灵活性,增加了边境执法的不确定性,弱化了TRIPS保障性条款,破坏系统性制衡机制。在超TRIPS边境措施的条约义务与国家经济发展的现实需求之间寻求新的平衡,是发展中国家成员面临的新挑战。发展中国家成员应寻求有利于发展中国家的解释和执法空间,充分利用CPTPP关于特定公共健康谅解条款和原则性条款,对CPTPP超TRIPS边境措施进行合理解释,达到“选择性适应”。加入CPTPP符合中国的长远利益,中国在推进执法严格化的同时,应充分利用CPTPP的灵活性,推动知识产权边境执法制度向着更加公平和正义的方向发展。

一种半耦合韧性断裂准则及其在TRIP780中的应用

为研究高强钢板材在冷成形下的损伤演化与韧性断裂行为,将DF2012韧性断裂准则修正为初始损伤判据,同时参考连续损伤力学理论引入损伤变量D以衡量材料的累积损伤,并将其耦合到塑性模型中,构建了一种半耦合韧性断裂准则。以TRIP780高强钢板为研究对象,针对不同应力状态设计了6种形状的试样,借助电阻损伤测量法与DIC数字图像法进行了力学性能试验并测定初始损伤位移。采用非相关流动准则(NAFR)的Drucker各向异性屈服函数和Swift-Voce硬化模型准确描述了材料的塑性变形过程,然后分别利用试验模拟混合法和逆向工程法对初始损伤模型和损伤演化参数进行了标定。使用Fortran语言将构建的本构模型与损伤演化模型编译为VUMAT子程序并嵌入ABAQUS/Explicit模块中进行断裂模拟预测,并与未耦合损伤模型进行比较。结果表明:构建的半耦合韧性断裂准则能够准确描述TRIP780板材在不同应力状态下变形后期的损伤诱导软化行为,预测的断裂位移最大相对误差仅为1.31%。相较于常用的非耦合断裂模型,所提模型针对具有软化效应的高强钢表现出明显的优越性,适合用于高强钢板冷冲压成形的破裂预测中。

基于“TRIP”教育理念的文旅融合人才培养体系的构建与实践

本文在TRIP教学理念指导下,指出当前文旅融合人才培养面临的主要问题,通过对文旅融合人才培养目标、培养模式、课程体系、评价体系四个方面构建文旅融合人才培养体系。