产品模型数据交换标准STEP研究

在设计和制造中,许多系统过去常常要处理技术产品数据。每个系统有它自己的数据格式,所以相同的信息必然在多个系统中多次存储,这会导致了信息的冗余和错误。STEP是一个广泛使用的ISO标准(ISO10303),描述了表示和交换数字产品信息的方式。研究了STEP的标准体系结构,并研究不同应用对象的STEP和STEP未来的发展趋势。

Controllable step-flow growth of GaN on patterned freestanding substrate

A new kind of step-flow growth mode is proposed,which adopts sidewall as step source on patterned GaN substrate.The terrace width of steps originated from the sidewall was found to change with the growth temperature and ammonia flux.The growth mechanism is explained and simulated based on step motion model.This work helps better understand the behaviors of step advancement and puts forward a method of precisely modulating atomic steps.

阿尔茨海默病细胞模型中β淀粉样蛋白介导ERK信号通路的STEP_(61)负性调控

背景:研究表明纹状体富集的酪氨酸磷酸酶61(striatal-enriched phosphatase,STEP_(61))在突触可塑性方面发挥重要作用。STEP位于后突触末端,影响突触增强的形成,可能的机制是使关键性信号蛋白如MAPK激酶ERK1/2去磷酸化并失活。目的:探讨STEP_(61)负性调控阿尔茨海默病细胞模型中β淀粉样蛋白介导的ERK信号通路的机制。方法:实验分3组,正常组为C57BL/6小鼠原代皮质神经元细胞;阿尔茨海默病细胞模型组是利用1μmol/L凝聚态的β淀粉样蛋白1-42加入皮质神经元细胞中1 h作为阿尔茨海默病细胞模型;β淀粉样蛋白1-42+RNAi组为在阿尔茨海默病细胞模型基础上,利用sRNAi技术制作STEP_(61)基因沉默组。应用Western Blot技术检测STEP_(61)的RNAi对ERK信号通路的影响。结果与结论:Western blot结果显示,阿尔茨海默病细胞模型组与正常组相比STEP_(61)蛋白表达增加了223%(P<0.05),使磷酸化STEP_(61)的比例减少到(75.6±4.6)%(P<0.05)。β淀粉样蛋白1-42+RNAi组STEP_(61)磷酸化的比例与阿尔茨海默病细胞模型组相比差异无显著性意义。同时阿尔茨海默病细胞模型组pE RK1/2的蛋白表达量较对照组减少(P<0.05),而β淀粉样蛋白1-42+RNAi组p ERK1/2的蛋白表达量较阿尔茨海默病细胞模型组显著增加(P<0.05)。结果说明:在阿尔茨海默细胞模型中证实了STEP_(61)调控β淀粉样蛋白介导的ERKs活性,并且很可能是通过脱磷酸化使他们失活而实现的。

基于TeamSTEPPS理论的案例情景教学法在急诊护理团队培训中的应用

急诊科具有危重患者多,突发状况多,医疗风险高等特点,目前国内大多数医院急诊科护士以团队形式开展工作,但临床工作中易出现职责分工不明确、配合不协调、组织抢救混乱等问题^([1])。团队培训是增强团队优质高效协作的重要途径^([2]),为进一步提升急诊护理团队协作,保障患者安全,本次研究将前期基于提高医疗质量和患者安全的团队策略与工具(team strategies and tools to enhance performance and patient safety,TeamSTEPPS)理论构建的急诊护理团队培训方案^([3])进行临床应用,取得了较好的效果。现报道如下。

"Five steps four quadrants" modularized en bloc dissection technique for accessing hepatic hilum lymph nodes in laparoscopic pancreaticoduodenectomy

BACKGROUND Although en bloc dissection of hepatic hilum lymph nodes has many advantages in radical tumor treatment,the feasibility and safety of this approach for laparo-scopic pancreaticoduodenectomy(LPD)require further clinical evaluation and investigation.AIM To explore the application value of the"five steps four quadrants"modularized en bloc dissection technique for accessing hepatic hilum lymph nodes in LPD patients.METHODS A total of 52 patients who underwent LPD via the"five steps four quadrants"modularized en bloc dissection technique for hepatic hilum lymph nodes from April 2021 to July 2023 in our department were analyzed retrospectively.The patients'body mass index(BMI),preoperative laboratory indices,intraoperative variables and postoperative complications were recorded.The relationships between preoperative data and intraoperative lymph node dissection time and blood loss were also analyzed.RESULTS Among the 52 patients,36 were males and 16 were females,and the average age was 62.2±11.0 years.There were 26 patients with pancreatic head cancer,16 patients with periampullary cancer,and 10 patients with distal bile duct cancer.The BMI was 22.3±3.3 kg/m²,and the median total bilirubin(TBIL)concentration was 57.7(16.0-155.7)µmol/L.All patients successfully underwent the"five steps four quadrants"modularized en bloc dissection technique without lymph node clearance-related complications such as postoperative bleeding or lymphatic leakage.Correlation analysis revealed significant associations between preoperative BMI(r=0.3581,P=0.0091),TBIL level(r=0.2988,P=0.0341),prothrombin time(r=0.3018,P=0.0297)and lymph node dissection time.Moreover,dissection time was significantly correlated with intraoperative blood loss(r=0.7744,P<0.0001).Further stratified analysis demonstrated that patients with a preoperative BMI≥21.9 kg/m²and a TIBL concentration≥57.7μmol/L had significantly longer lymph node dissection times(both P<0.05).CONCLUSION The"five steps four quadrants"modularized en bloc dissection technique for accessing the hepatic hilum lymph node is safe and feasible for LPD.This technique is expected to improve the efficiency of hepatic hilum lymph node dissection and shorten the learning curve;thus,it is worthy of further clinical promotion and application.

谐波驱动系统Back-stepping滑模控制研究

针对谐波传动系统动力学模型中存在的柔性变形、摩擦和运动误差等非线性因素。为了提高系统的传动精度,针对系统非线性刚度和静态误差因素进行了建模,并提出了一种Back-stepping滑模控制方法。利用Lyapunov稳定性理论,证明了闭环系统的误差是一致有界的。仿真结果表明,与PID控制相比,采用Back-stepping滑模控制,系统传动误差曲线峰峰值减小66.63%;负载端角速率误差曲线峰峰值减小77.35%。Back-stepping滑模控制能有效地补偿系统传动误差,抑制其负载端的速度波动,提高了系统的传动精度。

Performance improvement in stepped solar still modified by sponge layer

In this paper,the experimental investigation on the performance improvement of conventional stepped solar still is conducted.The steps are covered by the porous material to improve the performance of the conventional device and increase the evaporation rate.All the parameters,including the temperature on the glass surface,the water temperature inside the evaporation zone,and the amount of water produced in both conventional and modified stepped solar stills are measured and compared.The efficiency of two devices and their exergy efficiency have been calculated.Finally,the economic analysis of both devices has been done to check the economic feasibility of the modified device.The amount of freshwater generated during one day was 2244.4 and 3076.2 mL/m^(2),respectively for the conventional and modified stepped solar stills.As a result,the amount of water produced in one day by modified stepped solar still is 35.5% more than the conventional one.Also,the costs for the conventional and modified stepped solar stills have been calculated as 0.0359 and 0.029$/(L·m^(-2)),respectively.

Half-integer Shapiro steps in MgB_(2) focused He ion beam Josephson junctions

Half-integer microwave induced steps(Shapiro steps)have been observed in many different Josephson junction systems,which have attracted a lot of attention because they signify the deviation of current phase relation(CPR)and uncover many unconventional physical properties.In this article,we first report the discovery of half-integer Shapiro steps in MgB_(2)focused He ion beam(He-FIB)Josephson junctions.The half-integer steps'dependence on microwave frequency,temperature,microwave power,and magnetic field is also analyzed.We find that the existence of half-integer steps can be controlled by the magnetic field periodically,which is similar to that of high temperature superconductor(HTS)grain boundary junctions,and the similarity of the microstructures between gain boundary junctions and He-FIB junctions is discussed.As a consequence,we mainly attribute the physical origin of half-integer steps in MgB_(2)He-FIB junctions to the model that a He-FIB junction is analogous to a parallel junctions'array.Our results show that He-FIB technology is a promising platform for researching CPR in junctions made of different superconductors.

Transfer matrix method for free and forced vibrations of multi-level functionally graded material stepped beams with different boundary conditions

Functionally graded materials(FGMs)are a novel class of composite materials that have attracted significant attention in the field of engineering due to their unique mechanical properties.This study aims to explore the dynamic behaviors of an FGM stepped beam with different boundary conditions based on an efficient solving method.Under the assumptions of the Euler-Bernoulli beam theory,the governing differential equations of an individual FGM beam are derived with Hamilton’s principle and decoupled via the separation-of-variable approach.Then,the free and forced vibrations of the FGM stepped beam are solved with the transfer matrix method(TMM).Two models,i.e.,a three-level FGM stepped beam and a five-level FGM stepped beam,are considered,and their natural frequencies and mode shapes are presented.To demonstrate the validity of the method in this paper,the simulation results by ABAQUS are also given.On this basis,the detailed parametric analyses on the frequencies and dynamic responses of the three-level FGM stepped beam are carried out.The results show the accuracy and efficiency of the TMM.

Stability analysis of intermittently jointed rock slopes based on the stepped failure mode

In practical engineering,due to the noncontinuity characteristics of joints in rock slopes,in addition to plane failure,stepped sliding failure may occur for intermittently jointed rock slopes.Especially for intermittently bedding jointed rock slopes,the correlation and difference in strength parameters between joints and rock bridges,along with the various failure modes and intermittency of rock bridges,contribute to the complexity of stepped failure modes and the unpredictability of failure regions.Based on the upper-bound limit analysis method and multi-sliders step-path failure mode,considering the shear and tensile failure of rock bridges and the weakened relationship between the strength parameters of rock bridges and jointed surfaces,by introducing the modified M-C failure criterion and the formula for calculating the energy consumption of tensile failure of rock bridges,two failure mechanisms are constructed to obtain the safety factor(F_(s))of intermittently jointed rock slopes.The sequential quadratic programming method is used to obtain the optimal upper-bound solution for F_(s).The influence of multiple key parameters(slope height H,horizontal distance L,Slope angleβ,shear strength parameters of the rock bridgeφr and cr,Dimensionless parameter u,weakening coefficients of the internal friction angle and cohesion between the rock bridges and joint surfaces Kφand Kc)on the stability analysis of intermittently jointed rock slopes under the shear failure mode of rock bridges as well as under the tensile failure mode is also explored.The reliability of the failure mechanisms is verified by comparative analysis with theoretical results,numerical results,and landslide cases,and the variation rules of F_(s)with each key parameter are obtained.The results show that F_(s) varies linearly withφr and cr of the rock bridge and with K_(φ)and K_(c),whereas F_(s)changes nonlinearly with H and L.In particular,with the increase in Kφand Kc,Fs increases by approximately 52.78%and 171.02%on average,respectively.For rock bridge tensile failure,F_(s) shows a nonlinearly positive correlation withφr,cr,Kφand Kc.In particular,with the increase in Kφand Kc,Fs increases by approximately 13%and 61.69%on average,respectively.Fs decreases rapidly with increasing slope gradientβand decreasing dimensionless parameterμ.When Kφand Kc are both less than 1.0,the stepped sliding surface occurs more easily than the plane failure surface,especially in the case of tensile failure of the rock bridge.In addition,rock slopes with higher strength parameters,taller heights,and greater weakening coefficients are prone to rock bridge tension failure with lower Fs,and more attention should be given to the occurrence of such accidents in actual engineering.

基于STEP-NC的CNC集成技术研究

目的提供描述产品整个生命周期信息的统一数据模型,实现整个制造过程中产品信息的标准化,解决实现基于STEP-NC的CNC(计算机数字控制)制造技术集成问题.方法分析了STEP-NC的数据模型和程序结构,给出了STEP-NC程序文件的基本结构和STEPAP238文件的生成方法.结果生成符合STEP-NC的数控加工程序(AP238文件),从零件的几何模型(由CAD系统输出)中识别出需进行机械加工的制造特征.采用UG软件,实现了零件的设计、工艺规划和生成STEP-NC文件一体化,即实现了CAD/CAM的集成.结论STEP-NC程序在统一的数据模型基础上建立产品信息,保证了数据信息的集成和共享,促进了数控技术智能化、网络化和集成化的发展.

A novel dynamic step size LMS optimization scheme for interference reducing in FBMC-QAM

Filter bank multicarrier quadrature amplitude modulation(FBMC-QAM)will encounter inter-ference and noise during the process of channel transmission.In order to suppress the interference in the communication system,channel equalization is carried out at the receiver.Given that the con-ventional least mean square(LMS)equilibrium algorithm usually suffer from drawbacks such as the inability to converge quickly in large step sizes and poor stability in small step sizes when searching for optimal weights,in this paper,a design scheme for adaptive equalization with dynamic step size LMS optimization is proposed,which can further improve the convergence and error stability of the algorithm by calling the Sigmoid function and introducing three new parameters to control the range of step size values,adjust the steepness of step size,and reduce steady-state errors in small step sta-ges.Theoretical analysis and simulation results demonstrate that compared with the conventional LMS algorithm and the neural network-based residual deep neural network(Res-DNN)algorithm,the adopted dynamic step size LMS optimization scheme can not only obtain faster convergence speed,but also get smaller error values in the signal recovery process,thereby achieving better bit error rate(BER)performance.

STEP-NC——新一代机床控制器

STEP -NC是新近提出的采用STEP规范的数控机床数据接口标准。STEP -NC控制器将不再使用G、M代码来编程 ,而使用STEP标准的三维产品数据模型加上工艺和刀具信息直接产生加工程序。本文介绍了STEP -NC的基本概念、研究概况 。

面向开放环境的集成化STEP工具集GS-STEP的设计与实现

GS- STEP是一个面向开放环境的 STEP信息集成工具集 .为适应开放式 CIMS环境对信息集成的柔性需求 ,采用了系统独立性、协议无关性和层次化、模块化的开发策略 .这些策略使 GS- STEP能够方便地应用于各种CAx系统 ,也使其各功能部件可作为独立的软件包或开发平台分别实现商品化 ,从而体现“即插即用”思想与可扩充性原则 .该软件作为信息集成平台已成功地应用于 CIMS集成环境 GS- ICCC.文中从开发策略、系统结构、数据流和功能组织等角度阐述了 GS- STEP的设计与实现 .

基于STEP-NC的CNC系统中插补技术研究

STEP-NC是一个新的数控编程接口,基于STEP-NC的CNC系统是未来数控技术发展方向之一。在该系统中不但具有直线和圆弧插补功能,而且还具有样条曲线插补功能。开发了一个统一的基于NURBS样条曲线插补的通用插补器,推导出一个简洁的NURBS几何数据预处理算法,详细论述了基于等弧长的插补技术和插补原理。最后,通过仿真和实例加工验证了上述算法的有效性和可靠性。

一种基于STEP-NC的智能化CNC体系结构的研究

提出了一种基于STEP-NC的智能化STEP-CNC系统体系结构, 并详细介绍了其功能组成和系统特点, 最后给出了系统的实现方法。

Contribution to the Full 3D Finite Element Modelling of a Hybrid Stepping Motor with and without Current in the Coils

The paper presents our contribution to the full 3D finite element modelling of a hybrid stepping motor using COMSOL Multiphysics software. This type of four-phase motor has a permanent magnet interposed between the two identical and coaxial half stators. The calculation of the field with or without current in the windings (respectively with or without permanent magnet) is done using a mixed formulation with strong coupling. In addition, the local high saturation of the ferromagnetic material and the radial and axial components of the magnetic flux are taken into account. The results obtained make it possible to clearly observe, as a function of the intensity of the bus current or the remanent induction, the saturation zones, the lines, the orientations and the magnetic flux densities. 3D finite element modelling provide more accurate numerical data on the magnetic field through multiphysics analysis. This analysis considers the actual operating conditions and leads to the design of an optimized machine structure, with or without current in the windings and/or permanent magnet.

基于STEP-NC的网络化制造系统实现框架

为了解决在网络化制造中企业内部与企业间存在着大量异构信息,将STEP-NC与网络化制造相结合,企业内部产品信息统一使用STEP格式。设计了基于STEP-NC的网络化协同制造系统的基本框架,讨论了EXPRESS与XML的映射机制和方法,开发了STEP/XML映射模块,在此基础上结合MAS技术建立多个通过XML语言交换信息的Agent模型。

以智慧启迪“完美贴合”的未来--对话雅视集团及STEPPER品牌高层

在追求舒适、精准的配戴体验之路上,从业者精进技艺、别出心裁,提出了多种创造性的解决方案,只为向完美更进一步。第三十五届中国国际眼镜业展览会上,雅视集团及旗下深圳司徕柏(光学)有限公司带来了STEPPER品牌的最新战略动向--STEPPER VISIONCARE,以及全新的AMOS(雅姆斯)智能系统,为行业呈现了其对极致舒适和精准视力保护的愿景。

TWO-STEP TRICK TO HACK INTO CELLS

In the microscopic world of viruses and human cells,a high-stakes game of lock-picking is constantly unfolding.In a recent study published in Cell on July 3,researchers from Fudan University,ShanghaiTech University,and the Institute of Biophysics(IBP)under the Chinese Academy of Sciences cracked the code on how one particular coronavirus,HCoV-HKU1,manages to sneak its way into our cells using a cunning two-step approach(doi:10.1016/j.cell.2024.06.016).