Tbx 4 and Tbx 5 gene expression associated with appendage development and its relationship with the absence of the pelvic fin in Pampus argenteus

The Tbx family is first known through the study of their functions in the body and limbs,and its members Tbx4 and Tbx5 genes are important factors in determining the characteristics of the appendages.Pampus argenteus is one of the important economical marine fishes widely distributed in offshore areas.Therefore,it is necessary to study the role of Tbx family genes in the deletion of pelvic fin in P.argenteus.In this study,we cloned Tbx4 and Tbx5 cDNA sequence of P.argenteus(GenBank:MH709128 and MH712458).The Western blot and real time PCR were used to detect the expressions of Tbx4 and Tbx5 in different developmental stages and tissues of P.argenteus.In addition,whole-mount in-situ hybridization was used to study the localization of Tbx4 and Tbx5 genes in different developmental stages of P.argenteus.Results show that the translation of Tbx4 mRNA was inhibited during the critical period of pelvic fin development.Among different tissues,Tbx4 protein levels were the lowest in the abdominal epithelium,and even lower than that in the pectoral fin,suggesting that the protein expression was also inhibited in the abdominal epithelium of adult P.argenteus.Therefore,the results indicated that upstream genes regulation led to the key stage-specific and low expression of Tbx4 during pelvic fin development and in the abdominal epithelium.

Semi-analytical investigation of heat transfer in a porous convective radiative moving longitudinal fin exposed to magnetic field in the presence of a shape-dependent trihybrid nanofluid

The thermal examination of a non-integer-ordered mobile fin with a magnetism in the presence of a trihybrid nanofluid(Fe_3O_4-Au-Zn-blood) is carried out. Three types of nanoparticles, each having a different shape, are considered. These shapes include spherical(Fe_3O_4), cylindrical(Au), and platelet(Zn) configurations. The combination approach is utilized to evaluate the physical and thermal characteristics of the trihybrid and hybrid nanofluids, excluding the thermal conductivity and dynamic viscosity. These two properties are inferred by means of the interpolation method based on the volume fraction of nanoparticles. The governing equation is transformed into a dimensionless form, and the Adomian decomposition Sumudu transform method(ADSTM) is adopted to solve the conundrum of a moving fin immersed in a trihybrid nanofluid. The obtained results agree well with those numerical simulation results, indicating that this research is reliable. The influence of diverse factors on the thermal overview for varying noninteger values of γ is analyzed and presented in graphical representations. Furthermore, the fluctuations in the heat transfer concerning the pertinent parameters are studied. The results show that the heat flux in the presence of the combination of spherical, cylindrical, and platelet nanoparticles is higher than that in the presence of the combination of only spherical and cylindrical nanoparticles. The temperature at the fin tip increases by 0.705 759% when the value of the Peclet number increases by 400%, while decreases by 11.825 13% when the value of the Hartman number increases by 400%.

Heat dissipation enhancement method for finned heat sink for AGV motor driver's IGBT module

With the widespread use of high-power and highly integrated insulated gate bipolar transistor(IGBT),their cooling methods have become challenging.This paper proposes a liquid cooling scheme for heavy-duty automated guided vehicle(AGV)motor driver in port environment,and improves heat dissipation by analyzing and optimizing the core component of finned heat sink.Firstly,the temperature distribution of the initial scheme is studied by using Fluent software,and the heat transfer characteristics of the finned heat sink are obtained through numerical analysis.Secondly,an orthogonal test is designed and combined with the response surface methodology to optimize the structural parameters of the finned heat sink,resulting in a 14.57%increase in the heat dissipation effect.Finally,the effectiveness of heat dissipation enhancement is verified.This work provides valuable insights into improving the heat dissipation of IGBT modules and heat sinks,and provides guidance for their future applications.

基于FINS协议的计算机与PLC以太网通信

FINS协议用于OMRON的CompoBus/D、Controller Link、Ethernet等网络以及网络之间的通信。简要介绍了FINS协议,研究了基于FINS协议实现上位机和PLC以太网通信的方法。PLC选用OMRON CP1H型机,上位机采用Visual C++6.0编程,调用FINS指令向PLC发送命令,与PLC进行信息交换。给出部分程序代码。该方法可为进一步开发PLC监控系统提供了有价值的参考。

14 nm pFinFET 器件抗单粒子辐射的加固方法

为探究先进互补金属氧化物半导体(CMOS)工艺在空间应用中的可靠性问题,研究14 nm工艺下P型沟道鳍式场效应晶体管(pFinFET)器件中的抗单粒子瞬态(SET)加固策略。通过在器件中插入平行于鳍方向的重掺杂N型沟槽(Ntie)和P型沟槽(Ptie)来减缓SET的影响。三维TCAD仿真结果表明:加固之后器件的抗SET特性和沟槽本身的偏置条件相关。当重掺杂沟槽处于零偏状态时,抗辐射加固的性能最好,SET脉冲宽度降低程度可达40%左右;然而,当处于反偏状态时,由于特殊的电荷收集过程的存在,使得SET脉冲幅度反而会明显增大,脉冲宽度减小程度并不明显。此外,还研究沟槽面积、间距及掺杂浓度对pFinFET中的SET脉冲宽度的影响,得到提高抗SET效果的加固方法。

纳米FinFET的单粒子瞬态与Fin结构的相关性研究

工艺差异引起的Fin结构变化会造成纳米FinFET器件呈现不同的电学特性,使器件的单粒子瞬态效应(SET)复杂化。基于电学特性校准的14 nm SOI标准型FinFET器件,构建了弹头型、三角型、阶梯型、半圆型及底部椭圆型等5种结构,分析了SET的表征量与Fin结构参数间的相关性,并利用灰色理论,研究了它们之间的内在关联性。结果表明,器件的收集电荷量、沉积电荷量与Fin的截面积显著相关;SET电流峰值、电子-空穴对产生率峰值及双极放大系数同时依赖于Fin的截面积和等效沟道宽度,且对等效沟道宽度的依赖性更强。

Effect of periodic heat transfer on the transient thermal behavior of a convective-radiative fully wet porous moving trapezoidal fin

A moving trapezoidal profiled convective-radiative porous longitudinal fin wetted in a single-phase fluid is considered in the current article.The periodic variation in the fin base temperature is taken into account along with the temperature sensitive thermal conductivity and convective heat transfer coefficients.The modeled problem,which is resolved into a non-linear partial differential equation(PDE),is made dimensionless and solved by employing the finite difference method(FDM).The results are displayed through graphs and discussed.The effects of amplitude,frequency of oscillation,wet nature,Peclet number,and other relevant quantities on the distribution of temperature through the fin length and with the dimensionless time are investigated.It is deciphered that the periodic heat transfer gives rise to the wavy nature of the fin thermal profile against time.The analysis is beneficial in the design of fin structures for applications like solar collectors,space/airborne applications,and refrigeration industries.

基于拓扑优化的车用功率模块Pin-Fin设计方法

集成Pin-Fin散热器可以降低功率模块的结-流热阻,是车用电机控制器热管理的发展趋势。然而,传统参数设计方法无法定量表征Pin-Fin的形貌结构,设计自由度低、设计效果欠佳,难以实现Pin-Fin的热-流协同设计。基于变密度拓扑优化方法,该文提出一种Pin-Fin形貌结构的设计方法,建立Pin-Fin设计的变密度拓扑优化模型,分析模型参数对优化结果和收敛性的影响规律,形成以结-流热阻和冷却液压降为目标的协同优化方法,探索Pin-Fin结构的热-流耦合规律和强化换热方法,得到最优的Pin-Fin散热器形貌结构,搭建变流器实验平台和车用电机控制器样机,对标商业化圆形Pin-Fin结构,以及三角形、菱形和水滴形等其他形貌结构,计及母线电压、负荷电流和冷却液流量的影响,实验结果验证了所提模型方法的可行性和有效性。实验结果表明:基于拓扑优化方法设计的Pin-Fin结构,与传统结构相比可以降低12%的结-流热阻,消除了多芯片结温差异的80%,为车用功率模块和电机控制器研究提供新的思路。

Effect of temperature on heavy ion-induced single event transient on 16-nm FinFET inverter chains

The variations of single event transient(SET)pulse width of high-LET heavy ion irradiation in 16-nm-thick bulk silicon fin field-effect transistor(Fin FET)inverter chains with different driven strengths are measured at different temperatures.Three-dimensional(3D)technology computer-aided design simulations are carried out to study the SET pulse width and saturation current varying with temperature.Experimental and simulation results indicate that the increase in temperature will enhance the parasitic bipolar effect of bulk Fin FET technology,resulting in the increase of SET pulse width.On the other hand,the increase of inverter driven strength will change the layout topology,which has a complex influence on the SET temperature effects of Fin FET inverter chains.The experimental and simulation results show that the device with the strongest driven strength has the least dependence on temperature.

Finned Zn-MFI zeolite encapsulated noble metal nanoparticle catalysts for the oxidative dehydrogenation of propane with carbon dioxide

Oxidative dehydrogenation of propane with carbon dioxide(CO_(2)-ODP)characterizes the tandem dehydrogenation of propane to propylene with the reduction of the greenhouse gas of CO_(2)to valuable CO.However,the existing catalyst is limited due to the poor activity and stability,which hinders its industrialization.Herein,we design the finned Zn-MFI zeolite encapsulated noble metal nanoparticles(NPs)as bifunctional catalysts(NPs@Zn-MFI)for CO_(2)-ODP.Characterization results reveal that the Zn2+species are coordinated with the MFI zeolite matrix as isolated cations and the NPs of Pt,Rh,or Rh Pt are highly dispersed in the zeolite crystals.The isolated Zn2+cations are very effective for activating the propane and the small NPs are favorable for activating the CO_(2),which synergistically promote the selective transformation of propane and CO_(2)to propylene and CO.As a result,the optimal 0.25%Rh0.50%Pt@Zn-MFI catalyst shows the best propylene yield,satisfactory CO_(2)conversion,and long-term stability.Moreover,considering the tunable synergetic effects between the isolated cations and NPs,the developed approach offers a general guideline to design more efficient CO_(2)-ODP catalysts,which is validated by the improved performance of the bifunctional catalysts via simply substituting Sn4+cations for Zn2+cations in the MFI zeolite matrix.

First Recorded Account of a White Shark Agonistic Pectoral Fin Depression Behavior at Guadalupe Island, Mexico

An agonistic display by a white shark was observed and photographed during a cage dive at Guadalupe Island in November 2015. Exhibiting exaggerated pectoral fin depression, agonistic behaviors have been previously observed and described in several shark species. This account may be the first record of a white shark in close proximity to a caged diver, exhibiting strong pectoral fin depression significantly dipped, in the mid-agonistic display. Such displays should be considered as aggressive and potentially life-threatening by those using the ocean for recreational or professional purposes.

FinFET芯片TEM样品制备及避免窗帘效应方法

制备高质量纳米尺度芯片透射电子显微镜(TEM)样品对于探索半导体器件结构设计、材料分布与芯片性能之间的关系具有重要的意义。使用聚焦离子束(FIB)/扫描电子显微镜(SEM)双束系统制备14 nm鳍式场效应晶体管(FinFET)截面TEM样品,制备过程中从技术角度提出了两种自下而上制样方案来抑制窗帘效应。为扩大样品的可表征视场范围,在避免样品弯曲的前提下,提出了一种薄片提取方法。结果表明,离子束流越大,窗帘效应越严重,自下而上方法能有效规避窗帘效应;离子束电压30 kV时采用清洗截面(CCS)模式、5 kV/2 kV时采用矩形模式,样品台倾斜补偿角度为1.5°~3.5°,进行交叉减薄,且最终铣削长度控制在1μm时减薄效果最好;新的薄片提取方法改变了样品的铣削方向,在避免窗帘效应破坏感兴趣结构和样品弯曲的前提下,将样品的可表征视场范围扩大了5倍。研究结果对优化TEM样品制备方法以及芯片失效分析提供了参考。

Localized Theoretical Analysis of Thermal Performance of Individually Finned Heat Pipe Heat Exchanger for Air Conditioning with Freon R404A as Working Fluid

This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat exchangers with individually finned heat pipes. The fundamental parameters used for performance analysis were the number of fins per heat pipe, the number of heat pipes, the inlet temperatures, and the flow rates of hot and cold fluids. The heat exchanger under analysis uses Freon 404A as a working fluid in an air conditioning system for cooling in the Evaporator and energy recovery in the Condenser. The theoretical model is localized and applied individually to the Evaporator, Condenser, and heat exchanger regions. The results obtained through the simulation are compared with experimental results that use a global approach for the heat exchanger. The thermal quantities obtained through the theoretical model in the mentioned regions are air velocity, Nusselt number, thermal effectiveness, heat transfer rate, and outlet temperature. The comparisons made with global experimental results are in excellent agreement, demonstrating that the localized theoretical approach developed is consistent and can be used as a comprehensive analysis tool for heat exchangers using heat pipes.

Localized Theoretical Analysis of Thermal Performance of Individually Finned Heat Pipe Heat Exchanger for Air Conditioning with Freon R404A as Working Fluid

This work contributes to the improvement of energy-saving in air conditioning systems. The objective is to apply the thermal efficiency of heat exchangers for localized determination of the thermal performance of heat exchangers with individually finned heat pipes. The fundamental parameters used for performance analysis were the number of fins per heat pipe, the number of heat pipes, the inlet temperatures, and the flow rates of hot and cold fluids. The heat exchanger under analysis uses Freon 404A as a working fluid in an air conditioning system for cooling in the Evaporator and energy recovery in the Condenser. The theoretical model is localized and applied individually to the Evaporator, Condenser, and heat exchanger regions. The results obtained through the simulation are compared with experimental results that use a global approach for the heat exchanger. The thermal quantities obtained through the theoretical model in the mentioned regions are air velocity, Nusselt number, thermal effectiveness, heat transfer rate, and outlet temperature. The comparisons made with global experimental results are in excellent agreement, demonstrating that the localized theoretical approach developed is consistent and can be used as a comprehensive analysis tool for heat exchangers using heat pipes.

保温时间对钛合金板翅式换热器真空钎焊过程温度场及残余应力的影响

钛合金板翅式换热器成品率较低、残余应力较大,该文针对钛合金板翅结构真空钎焊过程开展热-固耦合建模与仿真研究,阐述了钎焊过程温度均匀性及残余应力分布特征,探明保温时间对钛合金板翅式换热器真空钎焊过程温度场及残余应力的影响机理.结果表明,板翅结构两侧温度较高,中部温度较低,延长保温时间可有效改善板翅结构的温度均匀性.残余应力均主要集中于翅片上表面与隔板背侧中部,在钎缝及夹持点处存在明显的应力集中现象,保温时间越长翅片钎缝的残余应力越小.模拟得到钛合金板翅式换热器真空钎焊中残余应力与试验结果相吻合,相对误差为5.3%,验证了该模型的准确性.

仿生正形尾鳍结构微通道流动与传热特性数值研究及结构优化

基于鱼类尾鳍在流动过程中的重要作用,仿生设计并建立了正形尾鳍结构微通道物理模型,研究了仿生尾鳍肋间距对微通道综合传热性能的影响,提取了尾鳍结构凹陷长轴相对长度Dt/Wch、决定尾鳍结构最大宽度的bt/Wch以及决定尾鳍结构最大高度的张角αt三个结构参数,数值分析了结构参数对仿生微通道平均摩擦因数、平均Nusselt数、综合性能因子以及热阻和泵功的影响规律;并通过均匀试验分析回归拟合和遗传算法多目标优化得到了正形尾鳍结构参数的最优解。结果表明,综合性能因子随着仿生肋间距的增大而减小,当间距为4 mm时,正形尾鳍结构微通道的综合性能因子变化范围为1.74~1.89,综合传热性能明显优于矩形光滑通道;随着Dt/Wch的增加、bt/Wch的减小或αt的增加,尾鳍结构微通道的综合传热性能提升,其中凹陷长轴相对长度Dt/Wch和高度张角αt影响较大。结构参数为Dt/Wch=0.476、bt/Wch=0.135、αt=146.96°时,微通道性能有较大提升。

含强化肋的PCM相变储热与传热特性数值研究

为了有效提升PCM相变储热器的性能,本文采用多种金属翅片对相变过程进行强化,并采用焓-多孔介质模型对相变储热过程进行了数值模拟,分析了不同金属材料和不同基体孔隙率对相变储热及传热特性的影响.研究结果表明,采用金属泡沫强化翅片能够增强导热和对流效应,优化流场对流涡分布,储热器相变储热时间大大缩短,耗时仅为无翅片工况的16.8%;采用铜金属泡沫翅片的储能效率略优于铝金属泡沫翅片,储热时间缩短3.47%;强化翅片孔隙率对储热性能影响较弱,孔隙率为0.4时最优,孔隙率为0.6时次之,孔隙率为0.8时最差.

尾翼控制小型超空泡航行体运动稳定性分析

为探究可偏转尾翼对小型超空泡航行体运动状态的影响,建立了具备尾翼控制功能的小型超空泡航行体非线性动力学模型,对航行体动力学系统进行仿真计算,根据Lyapunov指数谱和相轨图对系统稳定性进行判定,运用非线性动力学方法,对不同尾翼反馈增益下的稳定系统、周期振荡系统以及混沌系统进行分析,得到了速度衰减情况下无动力小型超空泡航行体保持稳定运动的反馈增益参数区间,结果表明,无动力小型超空泡航行体可以通过调整尾翼的反馈增益参数进行姿态控制并实现稳定运动。

换热翅片几何量数字化测量技术研究及在智能制造中的应用

为解决换热翅片开窗角度的数字化测量问题,研究了面向换热器智能制造产线的翅片几何量参数测量装置。该装置采用激光轮廓传感器进行非接触测量,对获取的多组原始轮廓数据进行数据剔除和取均值预处理,将处理后的数据逐点求导以识别兴趣测量区域,在各兴趣测量区域采用定长逐点步进的方式进行最小二乘拟合运算,选取最优拟合线段进行夹角计算,可自动实现对翅片8个开窗角度及3个长度参数的测量,设计了基于JSON的数据交互格式实现与制造执行系统的数据对接。实验结果表明:装置角度测量最大允许误差(MPE)为±0.5°,具备数字化测量及数据交互能力,测量精度满足企业质控需求。

基于液压控制技术的船舶自动应急抗倾覆装置设计

船舶在航行过程中受到波浪影响容易发生倾覆事故,对人员安全造成极大威胁。本文在研究Conolly船舶横摇模型的基础上,提出一种基于液压控制技术的船舶自动应急抗倾覆装置的设计方案,使用减摇鳍来降低船舶的横摇幅度,并通过DSP控制器+Conolly船舶横摇模型的闭环控制方案实现船舶自动应急抗倾覆的目的。通过升力传感器、行程反馈和角度反馈的信号,然后计算出最优的控制信号发送给液压缸并驱动减摇鳍,产生与船舶横摇方向相反的力矩,系统能够动态响应海况变化和船舶运动,对自动应急抗倾覆装置进行仿真,结果表明,系统具有较好的适应性和实时性。