Parameter Design of Current Double Closed Loop for T-Type Three-Level Grid-Connected Inverter

To reduce current harmonics caused by switching frequency,T-type grid-connected inverter topology with LCL filter is adopted.In view of the disadvantages of the slow response speed of the traditional current control and the failure to eliminate the influence of the LCL filter on the grid-connected current by using current PI control alone,a current double closed loop PI current tracking control is proposed.Through the theoretical analysis of the grid-connected inverter control principle,the grid-connected inverter control model is designed,and the transfer functionmodel of each control link is deduced,and the current loop PI regulator is designed at last.The simulation results show that the control strategy is feasible.

Laparoscopic pancreatic duct incision and stone removal and T-type tube drainage for pancreatic duct stone: A case report and review of literature

To study a more micro-invasive procedure for patients having pancreatic duct stones(PDS).Till now,there has been no report of laparoscopic pancreatic duct incision and stone removal and T-type tube drainage for PDS in the English literature.An 82-year-old man suffered from subxiphoid pain associated with a dilated pancreatic duct(7 mm)containing one stone,but without a mass in the head of the pancreas.Laparoscopic pancreatic duct incision,stone removal,and T-type tube drainage were successfully performed without intraoperative or postoperative complications.An uneventful operation was performed with laparoscopically completed procedures in 160 min.The intraoperative loss of blood was around 50 mL.After patient a discharge on day 11,complete relief from the subxiphoid pain was reported at a follow-up visit 15 mo later.Laparoscopic pancreatic duct incision with stone removal and T-type tube drainage is applicable in carefully selected patients and can be effectively and safely used for the treatment of the abdominal pain of chronic pancreatitis.

Resistance Characteristics of Hydraulic Oil through Isodiametric T-type Duct with Sharp Corners

Rational determination and reduction of local energy loss of oil flow at pipe junctions are of important significance to improve hydraulic pipeline＇s work efficiency, especially for complex hydraulic pipeline connected by isodiametric T-type ducts with sharp comers to get combined and divided flow. From this point of view, the formulae of resistance loss for combined flow and divided flow through isodiametric T-type duct with sharp comers as well as the correlations of resistance loss coefficients in the branches of the duct are derived using energy method. On this basis, resistance characteristics of hydraulic oil in the duct are obtained by numerical simulation of different flow modes, which are commonly applied in hydraulic pipelines, using computational fluid dynamics （CFD） method, and the reasons for the resistance loss are analyzed based on the pressure change mechanism in the flow field. A part of simulation results was validated with the reference data. The research shows that for combined flows the resistance loss of symmetrical is lower than that of unsymmetrical to obtain low speed in common branch, but to gain high speed is quite the contrary, for divided flows, the symmetrical is always a reasonable choice to reduce resistance loss. These conclusions can be applied to optimize the design of hydraulic pipeline.

Locking compression plate+T-type steel plate for postoperative weight bearing and functional recovery in complex tibial plateau fractures

Complex tibial plateau fractures can seriously affect quality of life and physical and mental health of patients.The anatomical relationship between the proximal tibial bone and soft tissue is complex,resulting in different types of tibial plateau fractures.Violent trauma can lead to displaced fracture,serious soft tissue injury,and potentially,dislocation of the knee joint.Therefore,tibial plateau fractures are extremely unstable.AIM To assess the use of locking compression plate(LCP)+T-type steel plate for postoperative weight bearing and functional recovery of complex tibial plateau fractures.METHODS Ninety-seven patients with complex tibial plateau fractures who underwent surgery at our hospital were selected for retrospective study.Forty-nine patients had been treated with LCP+T-type steel plate limited internal fixation(study group),and 48 patients with bilateral ordinary steel plate support(control group).The operation process index,postoperative rehabilitation related index,Rasmussen score of the knee joint,tibial plateau varus angle(TPA),tibial plateau retroversion angle(PA),and surgical complications of the two groups were compared.RESULTS The operation time and intraoperative bone graft volume in the study group were lower than those in the control group(P<0.05).There were no significant differences in surgical bleeding,anterior external incision length,postoperative drainage,hospital stay duration,and fracture healing time between the groups(P>0.05).There was no significant difference in the TPA and PA angle between the groups immediately and 18 mo after surgery(P>0.05).At 12 mo after surgery,the Rasmussen scale score was higher in the study group than in the control group(P<0.05).There was no significant difference in the Rasmussen scale score at 18 mo after surgery,and the radiology score at 12 and 18 mo after surgery,between the two groups(P>0.05).The postoperative complication rate in the study group(3.77%)was lower than that in the control group(15.09%;P<0.05).CONCLUSION LCP+T-type steel plate internal fixation has advantages in terms of minimizing trauma and enabling early postoperative functional exercise,promoting functional recovery and lower limb weight-bearing,and reducing postoperative complications.

Inhibitory actions of mibefradil on steroidogenesis in mouse Leydig cells： involvement of Ca^2＋ entry via the T-type Ca^2＋ channel

Intracellular cAMP and Ca^2＋ are involved in the regulation of steroidogenic activity in Leydig cells, which coordinate responses to luteinizing hormone （LH） and human ehorionic gonadotropin （hCG）. However, the identification of Ca^2＋ entry implicated in Leydig cell steroidogenesis is not well defined. The objective of this study was to identify the type of Ca^2＋ channel that affects Leydig cell steroidogenesis. In vitro steroidogenesis in the freshly dissociated Leydig cells of mice was induced by hCG incubation. The effects of mibefradil （a putative T-type Ca^2＋ channel blocker） on steroidogenesis were assessed using reverse transcription （RT）-polymerase chain reaction analysis for the steroidogenic acute regulatory protein （STAR） mRNA expression and testosterone production using radioimmunoassay. In the presence of 1.0 mmol L-1 extracellular Ca^2＋, hCG at 1 to 100 IU noticeably elevated both StAR mRNA level and testosterone secretion （P 〈 0.05）, and the stimulatory effects of hCG were markedly diminished by mibefradil in a dose-dependent manner （P 〈 0.05）. Moreover; the hCG-induced increase in testosterone production was completely removed when external Ca^2＋ was omitted, implying that Ca entry is needed for hCG-induced steroidogenesis. Furthermore, a patch-clamp study revealed the presence of mibefradil-sensitive Ca^24- currents seen at a concentration range that nearly paralleled those inhibiting steroidogenesis. Collectively, Our data provide evidence that hCG-stimulated steroidogenesis is mediated at least in part by Ca^2＋ entry carried out by the T-type Ca^2＋ channel in the Leydig cells of mice.

Ultra wideband CMOS digital T-type attenuator with low phase errors

A proposed inductive-phase-compensation ultra wideband CMOS digital T-type attenuator design based on an analysis of minimising phase errors is presented in this letter.In a standard CMOS technology,the proposed attenuator is analytically demonstrated to have low phase errors due to the inductive-phase-compensation network.A design equation is inferred and a wide-band 4dB attenuation bit digital attenuator with low phase errors is designed as a test vehicle for the proposed approach.

T-type calcium channel expression in cultured human neuroblastoma cells

Human neuroblastoma cells （SH-SY5Y） have similar structures and functions as neural cells and have been frequently used for cell culture studies of neural cell functions.Previous studies have revealed L-and N-type calcium channels in SH-SY5Y cells.However,the distribution of the low-voltage activated calcium channel （namely called T-type calcium channel,including Cav3.1,Cav3.2,and Cav3.3） in SH-SY5Y cells remains poorly understood.The present study detected mRNA and protein expres-sion of the T-type calcium channel （Cav3.1,Cav3.2,and Cav3.3） in cultured SH-SY5Y cells using real-time polymerase chain reaction （PCR） and western blot analysis.Results revealed mRNA and protein expression from all three T-type calcium channel subtypes in SH-SY5Y cells.Moreover,Cav3.1 was the predominant T-type calcium channel subtype in SH-SY5Y cells.

Actuating mechanism and design of a T-type linear ultrasonic motor

To take advantage of merits of higher output-power and efficiency of bolt-clamped transducer,a T-type linear ultrasonic motor was proposed in this paper.The proposed motor contained a horizontal transducer and a vertical transducer.The horizontal transducer included two exponential shape horns,and the vertical transducer contained one exponential shape horn.And the horns intersected at tip ends where a driving foot was located.The longitudinal vibrations of transducers were excited by the stretching vibration of PZT ceramics.Longitudinal vibrations were superimposed in the motor and generated elliptical trajectory at the driving foot.The actuating mechanism of the proposed motor was analyzed.The two working modals of the motor were gained with FEM.The resonant frequencies of two working modals were degenerated by adjusting the structural parameters.The motion trajectory of nodes on the driving foot was gained by transient analysis.The vibration amplitude of node on the driving foot indicates that the proposed motor has potential good output characteristics.The results verify the feasibility of the proposed design and provide instructions for the development of the new ultrasonic motor.

Design and Implementation of a Three-Phase Active T-Type NPC Inverter for Low-Voltage Microgrids

This paper presents the design and implementation of a 3 kVA three-phase active T-type neutral-point clamped (NPC) inverter with GaN power devices for low-voltage microgrids. The designed inverter is used in a battery-based energy system (BESS) for power conversion optimization in applications to low-voltage microgrids. A modular design method has been developed for the design and implementation of the AT-NPC inverter. Experimental verification has been carried out based on a 3-kW three-phase T-Type NPC grid-connected inverter. FPGA based digital control technique has been developed for the current control of the three-level three-phase grid inverter. A maximum efficiency of 98.49% has been achieved within a load range from 50% to 75%.

Macrophage migration inhibitory factor decreased T-type Ca^(2+) channel current through activating Src

Aims T-type Ca2+ current(ICaT)plays an important role in the pathogenesis of atrial fibrillation（AF）.The present study sought to investigate the role of Macrophage migration inhibitory factor（MIF）,a pleiotropic cytokine,in the regulation of T-type Ca2+ channel in atrium myocytes.Methods We used whole-cell voltage-clamp technique and biochemical assays to study the regulation and expression of ICa,T in mouse atrium myocytes（HL-1 cells）.Results Serum MIF concentrations was slightly increased in patients with AF compared to sinus rhythm（SR） controls.In cultured HL-1 cells, significant amounts of MIF were produced in response to hydrogen peroxide（H2O2）,but not AngiotensinⅡ（AngⅡ）. Mouse recombinant MIF（rMIF）（20 or 40 nM,24 h） suppressed peak ICa,T by-38%and-60%in a concentration-dependent manner,impaired the voltage-dependent activation of ICa,T,and down-regulated of TCC alG mRNA.Src inhibitors genistein and PPl significantly enhanced ICaT.The depression of ICa,T induced by rMIF could be reversed by genistein and PP1.Conclusions MIFis involved in the pathogenesis of AF,probably by decreasing ICa,T through impairment of the channel function and activation of c-Src kinases in atrium myocytes.

Calcium signaling and T-type calcium channels in cancer cell cycling

Regulation of intracellular calcium is an important signaling mechanism for cell proliferation in both normal and cancerous cells. In normal epithelial cells, free calcium concentration is essential for cells to enter and accomplish the S phase and the M phase of the cell cycle. In contrast, cancerous cells can pass these phases of the cell cycle with much lower cytoplasmic free calcium concentrations, indicating an alternative mechanism has developed for fulfilling the intracellular calcium requirement for an increased rate of DNA synthesis and mitosis of fast replicating cancerous cells. The detailed mechanism underlying the altered calcium loading pathway remains unclear; however, there is a growing body of evidence that suggests the T-type Ca2+ channel is abnormally expressed in cancerous cells and that blockade of these channels may reduce cell proliferation in addition to inducing apoptosis. Recent studies also show that the expression of T-type Ca2+ channels in breast cancer cells is proliferation state dependent, i.e. the channels are expressed at higher levels during the fast-replication period, and once the cells are in a non-proliferation state, expression of this channel isminimal. Therefore, selectively blocking calcium entry into cancerous cells may be a valuable approach for preventing tumor growth. Since T-type Ca2+ channels are not expressed in epithelial cells, selective T-type Ca2+ channel blockers may be useful in the treatment of certain types of cancers.

Evaluation of hollow fiber T-type zeolite membrane modules for ethanol dehydration

This work presents the design of hollow fiber T-type zeolite membrane modules with different geometric configurations. The module performances were evaluated by pervaporation dehydration of ethanol/water mixtures. Strong concentration polarization was found for the modules with big membrane bundles. The concentration polarization was enhanced at high temperature due to the higher water permeation flux. The increase of feed flow could improve water permeation flux for the membrane modules with small membrane bundle.Computational fluid dynamics was used to visualize the flow field distribution inside of the modules with different configurations. The membrane module with seven bundles exhibited highest separation efficiency due to the uniform distribution of flow rate. The packing density could be 10 times higher than that of the tubular membrane module. The hollow fiber membrane module exhibited good stability for ethanol dehydration.

希夏邦马峰地区始新世地壳加厚和隆升过程

中新世中期之前喜马拉雅山脉的隆升历史和深部动力机制,还存在极大的争议、缺乏基本的数据约束。喜马拉雅造山带核部高级变质岩的埋藏和折返过程可以约束地壳加厚和山脉隆升过程,但是现有的变质记录主要为渐新世晚期-中新世中期,始新世变质作用的分布范围、形成过程和地质意义仍然未被充分挖掘。本文首先厘定了希夏邦马峰(8027m)山体的基本岩石组成:下部为高喜马拉雅正/副片麻岩,上部为肉切村群变粒岩及贯入其中的淡色花岗岩席。进一步对1964年希夏邦马峰登山科考采集的眼球状片麻岩进行了变质作用相平衡模拟和独居石微区原位U-Th-Pb定年,确定了始新世变质记录的P-T-t演化轨迹:M1阶段中P/T型变质压力峰期,条件为~1.0GPa、~740℃(~22℃/km),变质年龄为~37Ma;后近等温降压至M2阶段低P/T型变质温度峰期,条件为0.5~0.4GPa、~760℃(45~57℃/km),变质年龄为~25Ma;在~18Ma左右冷却至固相线以下。希夏邦马峰~37Ma的中P/T型变质和地壳加厚事件与北喜马拉雅穹隆、高喜马拉雅主体、前陆飞来峰等地区的记录一致(40~37Ma,20~25℃/km),表明印度-亚洲初始碰撞约20Myr后中上地壳被堆叠埋藏至>33km以下,发生了广泛的整体性加厚和深熔作用。该事件与喜马拉雅内陆残留海最终退却的时间吻合,是喜马拉雅山脉初始隆升的诱因。喜马拉雅山脉不是晚新生代以来隆升的,而是经历了自始新世中期以来的长期地壳堆叠和隆升过程。

脓毒症合并2型糖尿病患者单核细胞人白细胞DR抗原的表达水平分析

目的观察2型糖尿病(T2DM)对脓毒症患者外周血单核细胞表面人白细胞DR抗原(HLA-DR)表达水平的影响。方法选取首都医科大学附属北京朝阳医院2021年3月至2022年2月收治的65例脓毒症合并T2DM(脓毒症合并T2DM组)、67例脓毒症未合并T2DM(脓毒症组)、60例T2DM患者(T2DM组)作为研究对象,以45例同期本院健康体检志愿者作为健康对照组。收集受试者性别、年龄、既往史、糖化血红蛋白(HbAlc)、人院时血糖、白细胞计数(WBC)淋巴细胞计数(LYM)超敏C-反应蛋白(hs-CRP)、主要感染部位,人院24h内进行序贯器官衰竭评分(SOFA)。采用流式细胞术检测外周血HLA-DR+CD14^(+)细胞表达百分比及平均荧光强度(MFI);并随访28d,观察T2DM对脓毒症患者28d预后的影响,比较不同预后患者HLA-DR^(+)CD14^(+)水平的差异。结果T2DM组HLA-DR^(+)CD14^(+)细胞表达百分比和MFI均明显低于健康对照组[HLA-DR^(+)CD14^(+)细胞表达百分比:87.72%(76.18%,93.64%)比94.86%(92.91%,95.70%),HLA-DR^(+)CD14^(+)MFI:10.80(8.45,14.45)比12.40(1.45,15.28)],脓毒症合并T2DM组和脓毒症组HLA-DRCD14^(+)细胞表达百分比和MFI均较健康对照组及T2DM组进一步降低[HLA-DR^(+)CD14^(+)细胞表达百分比:70.78%(42.22%,84.73%)、68.95%(44.95%,87.00%)比94.86%(92.91%,95.70%)、87.72%(76.18%,93.64%),HLA-DR^(+)CD14^(+)MFI:5.50(3.81,9.20)、5.29(3.35,9.59)比12.40(1.45,15.28)、10.80(8.45,14.45),均P<0.05]。脓毒症组和毒症合并T2DM组两组HLA-DR^(+)CD14^(+)细胞表达百分比和MFI、SOFA评分、28d病死率比较差异均无统计学意义(均P>0.05)。脓毒症组和脓毒症合并T2DM组死亡者的年龄明显大于生存者[岁:脓毒症组为68(60,74)比61(52,69),脓毒症合并T2DM组为66(64,73)比60(53,68),均P<0.05],SOFA评分明显高于生存者[分:脓毒症组为14(11,16)比8(5,11),脓毒症合并T2DM组为12(9,16)比8(6,11),均P<0.05],死亡组的HLA-DR^(+)CD14^(+)百分比和HLA-DR^(+)CD14^(+)MFI均明显低于生存组[HLA-DR^(+)CD14^(+)细胞表达百分比:脓毒症组为44.94%(28.01%,64.45%)比77.14%(47.41%,88.35%),脓毒症合并T2DM组为40.68%(34.83%,66.64%)比73.46%(58.44%,85.31%);HLA-DR^(+)CD14^(+)MFI:脓毒症组为3.92(2.30,5.44)比7.07(3.39,10.55),脓毒症合并T2DM组为3.90(3.34,6.04)比6.81(4.41,9.32),均P<0.05]。相关性分析显示:T2DM组、脓毒症组和脓毒症合并T2DM组HLA-DR^(+)CD14^(+)细胞表达百分比与hs-CRP均呈负相关(r值分别为-0.448、-0.628、-0.457,均P<0.001),MFI与hs-CRP亦呈负相关(r值分别为-0.289、-0.540、-0.323,均P<0.05)。脓毒症组和脓毒症合并T2DM组的HLA-DR^(+)CD14^(+)百分比与SOFA评分均呈负相关(r值分别为-0.520、-0.558,均P<0.001),MFI与SOFA评分也均呈负相关(r值分别为-0.327、-0.482,均P<0.01)。结论仑HLA-DR^(+)CD14^(+)水平在T2DM和脓毒症时均下降,但当脓毒症合并T2DM时,HLA-DR+CD14^(+)水平未发现进一步下降。

基于漏纵波模式的高频宽带低插损滤波器设计

采用常规的瑞利声表面波设计低插损、大带宽的高频声表滤波器,难以满足设计要求。该文设计了一种基于多层膜结构的漏纵波(LLSAW)的高频宽带低损耗声表面波(SAW)滤波器。确定了激发LLSAW的波导结构,建立器件的二维理论模型;研究了电极各项参数对杂散的影响,在此基础上对电极参数进行了优化设计。研究发现,将串联谐振器的反射栅对数设置为6时,可有效抑制通带内的杂散。设计了镜像T型及镜像π型LLSAW结构滤波器,并进行性能比较分析。结果表明,镜像T型结构更能抑制杂散响应,设计的镜像T型结构LLSAW滤波器的中心频率为3545 MHz,插入损耗为-1.416 dB,-3 dB带宽为274 MHz,带外抑制大于-30 dB。

一种液压挖掘机最优能耗的轨迹规划方法

为了降低液压挖掘机的运动能量消耗,实现各关节的合理有效作业,提出了基于T型速度曲线的关节插值方法,以实现液压挖掘机最优能耗轨迹规划。该方法将各关节的速度设定为匀加速、匀速和匀减速的形式以保证液压挖掘机在作业过程中的平稳性,以关节角度、角速度和角加速度为约束条件,利用改进的自适应遗传算法优化求解各关节的匀加(减)速和匀速运动时间,获得了各关节最优运动曲线,实现了液压挖掘机最优能耗轨迹规划。对基于T型速度曲线的插值规划方法进行仿真实验,并在相同条件下与四次多项式插值结果进行了对比。结果表明,该方法规划的轨迹能耗低,避免了各关节产生不必要的运动,有效减少了摩擦损耗,使得挖掘机可平稳、低能耗地完成作业。

On asymptotics of t-type regression estimation in multiple linear model

We consider a robust estimator (t-type regression estimator) of multiple linear regression model by maximizing marginal likelihood of a scaled t-type error t-distribution.The marginal likelihood can also be applied to the de-correlated response when the withinsubject correlation can be consistently estimated from an initial estimate of the model based on the independent working assumption. This paper shows that such a t-type estimator is consistent.

Formaldehyde increases intracellular calcium concentration in primary cultured hippocampal neurons partly through NMDA receptors and T-type calcium channels

Objective Formaldehyde at high concentrations is a contributor to air pollution. It is also an endogenous metabolic product in cells, and when beyond physiological concentrations, has pathological effects on neurons. Formaldehyde induces mis-folding and aggregation of neuronal tau protein, hippocampal neuronal apoptosis, cognitive impairment and loss of memory functions, as well as excitation of peripheral nociceptive neurons in cancer pain models. Intracellular calcium （[Ca2＋]i） is an important intracellular messenger, and plays a key role in many pathological processes. The present study aimed to investigate the effect of formaldehyde on [Ca2＋]i and the possible involvement of N-methyl-D-aspartate receptors （NMDARs） and T-type Ca2＋ channels on the cell membrane. Methods Using primary cultured hippocampal neurons as a model, changes of [Ca2＋]i in the presence of formaldehyde at a low concentration were detected by confocal laser scanning microscopy. Results Formaldehyde at 1 mmol/L approximately doubled [Ca2＋]i. （2R）-amino-5-phosphonopentanoate （AP5, 25 μmol/L, an NMDAR antagonist） and mibefradil （MIB, 1 μmol/L, a T-type Ca2＋ channel blocker）, given 5 min after formaldehyde perfusion, each partly inhibited the formaldehyde-induced increase of [Ca：＋]i, and this inhibitory effect was reinforced by combined application of AP5 and MIB. When applied 3 min before formaldehyde perfusion, AP5 （even at 50μmol/L） did not inhibit the formaldehyde-induced increase of [Ca2＋]i, but MIB （1 μmol/L） significantly inhibited this increase by 70%. Conclusion These results suggest that formaldehyde at a low concentration increases [Ca2＋]i in cultured hippocampal neurons; NMDARs and T-type Ca2＋ channels may be involved in this process.

某电厂低压加热器管板与壳体T型焊接接头开裂失效分析

某电厂低压加热器服役5年后,管板和壳体的T型焊缝部位发生严重开裂;通过宏观检查、断口形貌分析、金相组织分析、能谱分析(EDS)、化学成分分析和硬度检测等检验检测,对焊缝开裂原因进行了分析。分析表明:由于焊接热影响区(HAZ)存在对碱应力腐蚀开裂敏感的淬硬马氏体组织,且焊接接头未进行消应力热处理,在碱性环境中,管板焊接热影响区发生了碱脆,支裂纹在焊缝中扩展穿透造成设备失效。对T型焊接接头失效的原因进行分析,对类似场合换热器设计、制造和使用具有借鉴意义。

T形地连墙码头结构计算

针对T形地连墙结构受力影响因素复杂的问题,结合工程实例,利用STAAD软件采用竖向弹性地基梁法对码头结构进行分析。研究不同模型单元划分精度、地连墙入土深度以及回填料m值选取对地连墙结构内力的影响,结果表明:随模型单元划分精度的提高,地连墙结构海侧弯矩增大,陆侧弯矩减小,锚碇墙结构弯矩变化规律与之相反,最终两者内力趋于稳定;在踢脚稳定的前提下,随地连墙底端入土深度的增加,墙体结构海侧弯矩减小、陆侧弯矩增大、位移减小;随m取值变大,锚碇墙海侧弯矩增大、陆侧弯矩减小,且敏感度较高。研究结论可为T形地连墙码头结构的设计提供参考。