Optimization-based mode selection scheme for OAM millimeter wave system in the off-axis misalignment case

Millimeter-wave transmission combined with Orbital Angular Momentum(OAM)has the advantage of reducing the loss of beam power and increasing the system capacity.However,to fulfill this advantage,the antennas at the transmitter and receiver must be parallel and coaxial;otherwise,the accuracy of mode detection at the receiver can be seriously influenced.In this paper,we design an OAM millimeter-wave communication system for overcoming the above limitation.Specifically,the first contribution is that the power distribution between different OAM modes and the capacity of the system with different mode sets are analytically derived for performance analysis.The second contribution lies in that a novel mode selection scheme is proposed to reduce the total interference between different modes.Numerical results show that system performance is less affected by the offset when the mode set with smaller modes or larger intervals is selected.

Collision off-axis position dependence of relativistic nonlinear Thomson inverse scattering of an excited electron in a tightly focused circular polarized laser pulse

This paper presents a novel view of the impact of electron collision off-axis positions on the dynamic properties and relativistic nonlinear Thomson inverse scattering of excited electrons within tightly focused, circularly polarized laser pulses of varying intensities. We examine the effects of the transverse ponderomotive force, specifically how the deviation angle and speed of electron motion are affected by the initial off-axis position of the electron and the peak amplitude of the laser pulse. When the laser pulse intensity is low, an increase in the electron's initial off-axis distance results in reduced spatial radiation power, improved collimation, super-continuum phenomena generation, red-shifting of the spectrum's harmonic peak, and significant symmetry in the radiation radial direction. However, in contradiction to conventional understandings,when the laser pulse intensity is relatively high, the properties of the relativistic nonlinear Thomson inverse scattering of the electron deviate from the central axis, changing direction in opposition to the aforementioned effects. After reaching a peak, these properties then shift again, aligning with the previous direction. The complex interplay of these effects suggests a greater nuance and intricacy in the relationship between laser pulse intensity, electron position, and scattering properties than previously thought.

Prediction of mechanical properties for deep drawing steel by deep learning

At present,iron and steel enterprises mainly use“after spot test ward”to control final product quality.However,it is impossible to realize on-line quality predetermining for all products by this traditional approach,hence claims and returns often occur,resulting in major eco-nomic losses of enterprises.In order to realize the on-line quality predetermining for steel products during manufacturing process,the predic-tion models of mechanical properties based on deep learning have been proposed in this work.First,the mechanical properties of deep drawing steels were predicted by using LSTM(long short team memory),GRU(gated recurrent unit)network,and GPR(Gaussian process regression)model,and prediction accuracy and learning efficiency for different models were also discussed.Then,on-line re-learning methods for transfer learning models and model parameters were proposed.The experimental results show that not only the prediction accuracy of optimized trans-fer learning models has been improved,but also predetermining time was shortened to meet real time requirements of on-line property prede-termining.The industrial production data of interstitial-free(IF)steel was used to demonstrate that R2 value of GRU model in training stage reaches more than 0.99,and R2 value in testing stage is more than 0.96.

Simultaneous detection of CH_(4)and CO_(2)through dual modulation off-axis integrated cavity output spectroscopy

This study established a novel method for the simultaneous detection of two-component gases.Radio frequency(RF)white noise disturbance laser current and wavelength modulation were simultaneously used to improve the off-axis integrated cavity output spectroscopy technique,and a high-precision dual modulation OA-ICOS(RF-WM-OA-ICOS)system was established.The two laser beams were coupled into one laser beam that was applied incident to the cavity of RF-WM-OA-ICOS system.The second harmonic signals of CH_(4)and CO_(2)gas simultaneously appeared in the rising or falling edge of a triangular wave.This method was used to measure CH_(4)and CO_(2)with different concentrations.The results indicated that the proposed system has high stability and can accurately and simultaneously measure the concentrations of CH_(4)and CO_(2),with an optimal integration time of 220 s.The minimum detection limit was 10 ppb for CH_(4)and 1.5 ppm for CO_(2).The corresponding noise equivalent absorption sensitivity values were calculated as 2.67×10^(-13)cm^(-1)·Hz^(-1/2)and 5.18×10^(-11)cm^(-1)·Hz^(-1/2),respectively.The proposed dual-component gas simultaneous detection method can also be used for high-precision simultaneous detection of other gases.Therefore,this study may serve as a reference for developing portable multicomponent gas analyzers.

Characteristic Analysis of Off-Axis Meta-Lens

Meta-lens are a new type of planar optical element that can flexibly manipulate the phase, polarization and amplitude of the beam, and are currently receiving a great deal of attention as they are easier to process and manufacture. Off-axis meta-lens are a special type of meta-lens with a certain degree of dispersion that can be used as a beam-splitting element, providing a unique and feasible way to realize micro-miniature instruments. We analyze the effects of different numerical apertures and off-axis angles on the spectral resolution, focusing efficiency and simulation results of off-axis meta-lens to provide ideas for subsequent research and application of off-axis meta-lens. A number of off-axis meta-lens with parameters NA = 0.408 α = 13°, NA = 0.18 α = 13° and NA = 0.408 α = 20° were simulated through Lumerical software. The results show that the off-axis angle is related to the resolution;the larger the angle, the better the spectral resolution but the lower the focusing efficiency;when the numerical aperture is smaller, the smaller the coverage of the phase distribution, which will lead to a larger deviation between simulation and theory. The designer needs to balance the numerical aperture, off-axis angle and other parameters reasonably according to the requirements in order to achieve the desired effect. The findings of this study have important reference values for the theoretical analysis of off-axis meta-lens and the design of parameters in practical applications. .

Tianmen textile machinery:Independently developed the drawing frame equipment

Hubei Tianmen Textile Machinery Co.,Ltd.is a well-known enterprise and key high-tech enterprise in China textile industry.The company's leading product,drawing frame,has completely independent intellectual property rights,among which TM 11 is well received by users and has a high market share in China.

Research on the Reform of the Course“Reading of Concrete Structure Plan and Construction Drawings”Under the Background of“Promoting Teaching and Learning Through Competitions”

The inherent teaching approach can no longer meet the demands of society.In this paper,current issues within the teaching landscape of architectural engineering technology in higher vocational colleges as well as the policies and teaching demands that formed the basis of this model were analyzed.The study shows the importance of the implementation of the teaching model“promoting teaching and learning through competitions.”This model puts emphasis on the curriculum and teaching resources,while also integrating the teaching process and evaluation with competition.These efforts aim to drive education reform in order to better align with the objectives of vocational education personnel training,while also acting as a reference for similar courses.

基于Visio Drawing Control控件的图形化潮流计算软件开发

针对VC,Delphi等工具开发电力系统分析计算软件图形可视化的缺陷,提出并研究了一种基于VisioDrawing Control图形控件,利用VC进行二次开发的图形化电力系统潮流计算软件开发的技术,研究了基于该控件的图形化建模方法及电网拓扑结构的自动识别,开发了实用的电力系统图形化潮流计算软件.实践表明,基于Visio Drawing Control的二次开发技术为图形化电力系统潮流计算软件的开发提供了新的有效的途径.

工程图协同审议与存档管理系统VHDrawings的设计与实现

工程设计单位的审图工作是一个需要多人参与、多次往复的过程。用传统的方法传递设计图与修改意见,速度慢且易出错,限制了工程设计单位工作效率的提高。该文介绍了一个计算机辅助的工程图协同审议与存档管理系统VHDrawings的设计与实现。着重讨论了协同审图工作流的管理以及工程图自动识别技术在图档管理中的应用。为设计单位提高工作效率、优化管理流程提供了一种参考。

eDrawings在《工程制图》多媒体课件中的应用

分析了在《工程制图》多媒体课件中使用AutoCAD和SolidWorks两种软件时存在的不足,阐述了eDrawings在课件中的应用优势。论述了CAD二维图形和SolidWorks三维模型转换成eDrawings文件的方法、常见问题、问题产生的原因和解决方法。给出了应用实例。

海外项目shop drawing的理解

通过对海外项目shop drawing(细化图)的理解,阐述了shop drawing的定义以及绘制shop drawing过程中需要注意的问题。通过实例分析,为同类型国际港口工程中细化设计提供参考和借鉴。

运用Pro/E Drawing参数设置功能生成压缩机零部件标准工程图

作为机械三维参数化设计软件的佼佼者,Pro/E以其卓越的设计、分析和运动仿真等功能为企业新产品的开发带来了巨大的效益,但对企业来说新产品开发的最终目标是加工与生产。因此进一步开发研究使用Pro/E Drawing模块的各种功能,为企业定制出符合国标要求的零部件工程图,具有巨大的应用前景。

Short-term effects of drawing water for connectivity of rivers and lakes on zooplankton community structure

During 28-29, September 2005, water was drawn from Hanjiang River and Houguan Lake to the Yangzi River via Sanjiao Lake and Nantaizi Lake in Wuhan in order to provide favorable conditions for ecosystem restoration. To evaluate the feasibility and validity of drawing water as a means of ecosystem restoration, zooplankton populations were studied 3 times （before, immediately after finishing and a month after drawing water） at seven locations from 27 Sept. 2005 to 2 Nov. 2005. Water quality in the lakes was mostly improved and zooplankton species richness decreased as soon as drawing water had finished but increased a month after drawing water. Zooplankton density and biomass was reduced in the lakes by drawing water but was increased at the entrance to Sanjiao Lake because of landform geometry change. Before drawing water, most species in Sanjiao Lake e.g., Brachionus sp. and Keratella sp. were tolerant of contamination. After drawing water oligotrophic-prone species such as Lecane ludwigii and Gastropus stylifer emerged. We conclude that drawing water could be important for improving water quality and favour ecosystem restoration. Dilution of nutrient concentrations may be an important role in the effect.

EFFECTS OF SPECIFIED BLANK SIZE ON BODY WRINKLING DURING HYDRODYNAMIC DEEP DRAWING OF TAPERED RECTANGULAR BOX

In this paper, the forming features of tapered rectangular box during hydrodynamic deep drawing are studied by means of FEM.The effect rules of square blank corner corner amount on body wrinkling are recognized and corresponding methods are discussed. At last, the results of FEM are verified by experi- ment.

A LOOP DRAWBEAD RESTRAINING FORCE MODEL IN SHEET METAL DEEP DRAWING PROCESS

In sheet metal forming, drawbeads are often used to control uneven material flow which may cause defects such as wrinkles, fracture, surface distortion and springback. Appropriate setting and adjusting the drawbead force is one of the most important pa- rameters in sheet metal forming process control. This paper derives the model of loop drawbead restraining force (DBRF) using plastic forming theory, and gives the min imum blankholding force. Experiments are carried out to verify the proposed DBRF model. The good agreement between the calculated values and experiments data justi- fies the proposed loop drawbead restraining force model.

RESEARCH ON THE EVALUATION METHOD OF FRICTION AND LUBRICATION IN DEEP DRAWING

The deformation characteristic of bland in deep drawing is discussed. It is pointed out that the friction and lubrication conditions in for drawing are different from that in mechanical motion or machine work or other plastic process. The common test methods in laboratories are analyzed. It shows that though all those test methods can test the friction coefficient, the probe test method is most suitable for the research of friction and lubrication and the process in deep drawing, for this method is identical with the actual work condition either from the test principle or deformation status of the blank. Last the successful application in the deep drawing simulator newly developed the the probe method are intro- duced in detail.

EFFECTS OF HIGH-DENSITY CURRENT PULSES ON WORK HARDENING BEHAVIORS OF AUSTENITE STAINLESS STEEL IN WIRE-DRAWING DEFORMATION

The influence of high-density pulsing current on the work-hardening behaviour of H0Cr17Ni6Mn3 and 1Cr18Ni9 stainless steels in wire-drawing deformation processes has been studied. It was found that the drawing stress and the work-hardening rate of wires were significantly reduced by applying current pulses in drawing process. The work-hardening behavior of the multi-courses drawing deformation can be well described by Hollomon formula σ=κΕn. With the application of current pulses in drawing deformation, the work-hardening exponents of H0Cr17Ni6Mn3 steel wires and 1Cr18Ni9 stainless steel wires were reduced by 33% and 45%, respectively, and their work-hardening coefficients were reduced by 41% and 47%, respectively. It was also found that the work-hardening coefficient of wires was reduced with the increment of the frequency of current pulses, while the work-hardening exponents of both steels were insensitive to the pulsing frequency.

Subsurface macro-inclusions and solidified hook character in aluminum-killed deep-drawing steel slabs

Subsurface macro-inclusions and hooks are detrimental to the surface quality of deep-drawing steel sheets. However, little is known about the relationship between macro-inclusions and hooks. Thus, in this work, two ultralow carbon （ULC） steel slabs and two low carbon （LC） aluminum-killed steel slabs were sampled to study the relationship between hooks and subsurface macro-inclusions, which were detected on the cross-sections of steel samples with an area of 56058 mm2 using an automated scanning electron microscopy/energy-disper-sive X-ray spectroscopy system. Results show that subsurface inclusions larger than 200 μm were almost entrapped by hook structures, whereas the location of other inclusions smaller than 200μm had no obvious dependence on the location of solidified hooks. Furthermore, the number density （ND） of subsurface inclusions larger than 200μm decreased from 0.02 to 0 cm-2 in ULC steel as the mean hook depth decreased from 1.57 to 1.01 mm. Similar trends were also observed in LC steel. In addition, the detected inclusions larger than 200μm were concentrated in the region near the slab center （3/8 width-5/8 width）, where hook depths were also larger than those at any other locations. Therefore, minimizing the hook depth is an effective way to reduce inclusion-induced sliver defects in deep-drawing steels.

High-Performance Solid-State Supercapacitors Fabricated by Pencil Drawing and Polypyrrole Depositing on Paper Substrate

A solid-state powerful supercapacitor(SC) is fabricated with a substrate of Xerox paper. Its current collector based on a foldable electronic circuit is developed by simply pencil drawing. Thin graphite sheets on paper provide effective channels for electron transmission with a low resistance of 95 X sq-1. The conductive organic material of polypyrrole coated on thin graphite sheets acts as the electrode material of the device. The as-fabricated SC exhibits a high specific capacitance of 52.9 F cm-3at a scan rate of 1 m V s-1. An energy storage unit fabricated by three full-charged series SCs can drive a commercial light-emitting diode robustly. This work demonstrated a simple, versatile and costeffective method for paper-based devices.

谈国际港口工程中Shop Drawing的绘制

通过对巴基斯坦卡拉奇卡西姆港已实施的国际集装箱码头施工总承包项目现场施工图ShopDrawing的绘制,总结了绘制ShopDrawing的前提条件以及在图纸绘制过程中需要注意的事项,为同类型国际港口工程中细化设计提供了一些参考和借鉴。