Small-signal analysis of a rectangular helix structure traveling-wave-tube

This paper investigates the properties of traveling wave-beam interaction in a rectangular helix traveling-wave-tube （TWT） for a solid sheet electron beam. The ＂hot＂ dispersion equation is obtained by means of the self-consistent field theory. The small signal analysis,which includes the effects of the beam parameters and slow-wave structure （SWS） parameters,is carried out by theoretical computation. The numerical results show that the bandwidth and the small-signal gain of the rectangular helix TWT increase as the beam current increases;and the beam voltage not obviously influences the small signal gain. Among different rectangular helix structures,the small-signal gain increases as the width of the rectangular helix SWS increases,however,the bandwidth decreases whether structure parameters a and L or ψ and L are fixed or not.In addition,a comparison of the small-signal gain of this structure with a conventional round helix is made.The presented analysis will be useful for the design of the TWT with a rectangular helix circuit.

The Triple Helix of innovation as a double game involving domestic and foreign actors

Purpose:The collaboration relationships between innovation actors at a geographic level may be considered as grouping two separate layers,the domestic and the foreign.At the level of each layer,the relationships and the actors involved constitute a Triple Helix game.The paper distinguished three levels of analysis:the global grouping together all actors,the domestic grouping together domestic actors,and the foreign related to only actors from partner countries.Design/methodology/approach:Bibliographic records data from the Web of Science for South Korea and West Africa breakdown per innovation actors and distinguishing domestic and international collaboration are analyzed with game theory.The core,the Shapley value,and the nucleolus are computed at the three levels to measure the synergy between actors.Findings:The synergy operates more in South Korea than in West Africa;the government is more present in West Africa than in South Korea;domestic actors create more synergy in South Korea,but foreign more in West Africa;South Korea can consume all the foreign synergy,which is not the case of West Africa.Research limitations:Research data are limited to publication records;techniques and methods used may be extended to other research outputs.Practical implications:West African governments should increase their investment in science,technology,and innovation to benefit more from the synergy their innovation actors contributed at the foreign level.However,the results of the current study may not be sufficient to prove that greater investment will yield benefits from foreign synergies.Originality/value:This paper uses game theory to assess innovation systems by computing the contribution of foreign actors to knowledge production at an area level.It proposes an indicator to this end.

Ferroelectricity induced by the absorption of water molecules on double helix SnIP

We study the ferroelectricity in a one-dimensional(1D)system composed of a double helix SnIP with absorbing water molecules.Our ab initio calculations reveal two factors that are critical to the electrical polarization.The first one is the orientation of polarized water molecules staying in the R2 region of SnIP.The second one is the displacement of I atom which roots from subtle interaction with absorbed water molecules.A reasonable scenario of polarization flipping is proposed in this study.In the scenario,the water molecule is rolling-up with keeping the magnitude of its electrical dipole and changing its direction,meanwhile,the displacement of I atoms is also reversed.Highly tunable polarization can be achieved by applying strain,with 26.5%of polarization enhancement by applying tensile strain,with only 4%degradation is observed with 4%compressive strain.Finally,the direct band gap is also found to be correlated with strain.

A novel slotted helix slow-wave structure for high power Ka-band traveling-wave tubes

A novel slotted helix slow-wave structure （SWS） is proposed to develop a high power, wide-bandwidth, and high reliability millimeter-wave traveling-wave tube （TWT）. This novel structure, which has higher heat capacity than a conven- tional helix SWS, evolves from conventional helix SWS with three parallel rows of rectangular slots made in the outside of the helix tape. In this paper, the electromagnetic characteristics and the beam-wave interaction of this novel structure operating in the Ka-band are investigated. From our calculations, when the designed beam voltage and beam current are set to be 18.45 kV and 0.2 A, respectively, this novel circuit can produce over 700-W average output power in a frequency range from 27.5 GHz to 32.5 GHz, and the corresponding conversion efficiency values vary from 19% to 21.3%, and the maximum output power is 787 W at 30 GHz.

Middle or low water pressure direct spiral double helix converging nozzle structure optimization and flow field analysis

In order to solve the problem of using new nozzle is proposed in fire rescue robot. middle or low water pressure to form fine water mist, a Existing water mist nozzles are basically used for high pressure and in large size, complex structure and poor low pressure atomization effect in comparison with requirement of snake-like fire rescue robots. On the basis of comprehensive typical spray noz- zles, a direct spiral double helix converging nozzle （DSDHCN） is proposed, which has the advanta- ges of small volume, light weight, simple structure, and convenient installation. To make the spray nozzle have good performance, and meet the requirements of more efficient fire extinguishing, a nu- merical study is carried out to analyze the internal and external full flow field of nozzle. A gas-liquid two-phase flow is applied to simulate the external full flow field of nozzle with VOF model in fluent software. The simulation results show the real situation of water flow out of the atomization nozzle and the water jet trajectory. Some simulations about middle or low water pressure direct spiral double he- lix converging optimized nozzle have been done in 30bar pressure. The simulation results show that the optimized nozzle structure not only makes the spray droplets have a good cone angle, but also have a sufficient axial velocity,which proves the structure rationality of the proposed optimized nozzle.

A three-dimensional time-dependent theory for helix traveling wave tubes in beam-wave interaction

This paper presents a three-dimensional time-dependent nonlinear theory of helix traveling wave tubes for beam- wave interaction. The radio frequency electromagnetic fields are represented as the superposition of azimuthally sym- metric waves in a vacuum sheath helix. Coupling impedance is introduced to the electromagnetic field equations＇ stimulating sources, which makes the theory easier and more flexible to realize. The space charge fields are calculated by electron beam space-charge waves expressed as the superposition solutions of Helmholtz equations. The focusing forces due to either a solenoidal field or a periodic permanent magnetic field is also included. The dynamical equations of electrons are Lorentz equations associating with electromagnetic fields, focusing fields and space-charge fields. The numerically simulated results of a tube are presented.

THE COUPLING IMPEDANCE OF VANE-LOADED TAPE HELIX SLOW-WAVE STRUCTURE

Based on the actual vane-loaded tape helix slow wave structure, a new theoretical analytic model for calculating coupling impedance is proposed by Chen Qingyou, et al.(1999)with calculated values of dispersion in good agreement with measured ones. In this paper, it is continued to use this model to calculate the coupling impedance of such a structure, and analyze the effects of the propagation power within vane gaps and the helix gap on the coupling impedance.As a result, the theoretical values are found to be in good agreement with the measured ones,with the maximum difference less than ±18%.

Innovative Teaching Research on Literary Theory and Criticism

As a core compulsory course for English majors majoring in teacher education,Literary Theory and Criticism plays an important role in enhancing text understanding,cultivating critical thinking,and shaping correct values in the future development of students.Influenced by traditional teaching ideas,students have many difficulties when learning this course,such as insufficient theoretical understanding,inadequate ability improvement,and not enough investment in course learning.In response to the above issues,this course focuses closely on the fundamental task of“cultivating virtue and nurturing people”,relying on modern information technology and introducing research methods of digital humanities.This course uses“7C”teaching mode under the“three-level integration”,in which“teaching”and“education”are carried out synchronously,and“teacher”and“student”are developed together,in order to greatly enhance students’learning participation and course satisfaction.

Helix-like structure formation of a semi-flexible chain confined in a cylinder channel

Molecular dynamics method is used to study the conformation behavior of a semi-flexible polymer chain confined in a cylinder channel.A novel helix-like structure is found to form during the simulation.Moreover,the detailed characteristic parameters and formation probability of these helix-like structures under moderate conditions are investigated.We find that the structure is not a perfect helix,but a bundle of elliptical turns.In addition,we conduct a statistical analysis for the chain monomer distribution along the radial direction.This research contributes to our understanding of the microscopic conformation of polymer chains in confined environments filled with a solvent.

Theoretical research on the performance of a practical helix travelling wave tube

On the basis of a rigorous field theory, two different physical models of attenuator and sever have been proposed. One is named High attenuation （HATT） model in which both attenuator and sever are considered as a unified attenuator, but the sever is regarded as an area of very high loss; the other is called Sever and attenuator （SATT） model in which the sever is modelled as a drift area in which the electric and magnetic fields both vanish. A complex function is derived and potential sinking effect is also considered. Thus, a set of more practical self-consistent equations of nonlinear beam-wave interaction is formulated. Simulations are carried out under the conditions of the two different physical models, and the simulation results are compared with the experimental data. The results show that in the case of single signal drive, the unknown second harmonic should be included for predicting the saturated output power. It is also evident that the SATT model and the HATT model predict the same physical nature, whereas the results predicted by the HATT model are much closer to the experimental data than those obtained from the SATT model. Therefore, these results provide a strong theoretical basis for designing broadband and high gain helix travelling wave tubes.

Beyond a Quartic Polynomial Modeling of the DNA Double-Helix Genetic Code

By combination of finite number theory and quantum information, the complete quantum information in the DNA genetic code has been made likely by Planat et al. (2020). In the present contribution a varied quartic polynomial contrasting the polynomial used by Planat et al. is proposed that considered apart from the golden mean also the fifth power of this dominant number of nature to adapt the code information. The suggested polynomial is denoted as g(x) = x4 - x3 - (4 - ϕ2 )x2 + (4 – ϕ2)x + 1, where is the golden mean. Its roots are changed to more golden mean based ones in comparison to the Planat polynomial. The new coefficients 4 – ϕ2 instead of 4 would implement the fifth power of the golden mean indirectly applying . As an outlook, it should be emphesized that the connection between genetic code and resonance code of the DNA may lead us to a full understanding of how nature stores and processes compacted information and what indeed is consciousness linking everything with each other suggestedly mediated by all-pervasive dark constituents of matter respectively energy. The number-theoretical approach to DNA coding leads to the question about the helical structure of the electron.

Design and motion control analysis of double helix wall climbing robot

For the detection environment of complex walls such as high-rise buildings,a double helix wall climbing robot(DHWCR)with strong adsorption force and good stability is designed and developed,which uses symmetrical propellers to provide adsorption force.The symmetrical driving structure can provide smooth thrust for the DHWCR,so that the robot can be absorbed to the wall surface with different roughness.A left and right control frame with multiple degrees of freedom is designed,which can adjust the fixed position of the brushless propeller motor in the front and back directions,realize the continuous adjustable thrust direction of the robot,and improve the flexibility of the robot movement.Using the front wheel steering mechanism with universal joint,the steering control of the DHWCR is realized by differential control.In the vertical to ground transition,the front and rear brushless motors can provide the pull up and oblique thrust,so that the DHWCR can smoothly transition to the vertical wall.The motion performance and adaptability of the DHWCR in the horizontal ground and vertical wall environment are tested.The results show that the DHWCR can switch motion between the horizontal ground and vertical wall,and can stably adsorb on the vertical wall with flexible attitude control.The DHWCR can move at a fast speed.The speed on the horizontal ground is higher than that on the vertical wall,which verifies the feasibility and reliability of the DHWCR moving stably on the vertical wall.

协同创新理论下交互式智能包装三螺旋耦合机制的实证研究

目的运用三螺旋理论分析交互式智能包装设计中科学、艺术与技术内核的协同创新,扩大耦合界面,提升三螺旋内部进化动力,为智能包装设计的可持续创新设计提供新的思路和方向。方法结合模糊层次分析法(F-AHP),构建交互式智能包装三螺旋耦合机制研究模型,论证“科-艺-技”三方在保持各自形成生态循环、情感循环与反馈循环后,通过“指导-藻饰-支撑”三螺旋相互促进,实现交互式智能包装设计的创新模式。结论通过三螺旋耦合机制对交互式智能包装三元驱动力的探析,将“万物物联”“多元共生”“性能跨越”三轴协同的跨界融合,有机整合了科学、艺术与技术三方优势在互补、融合驱动与交叉创新后形成的场力,对交互式智能包装设计的创新具有指导作用,并在此基础上提出对应的设计原则与设计策略,为智能包装智慧设计研究效用的最大化提供理论依据和实践指导。

教育数字化可持续发展的UGBS机制——从何处来?向何处去?

文章从历史哲学和政治哲学的高度出发,认为教育信息化是教育领域的“工业革命”,目标是实现作为“信息型”实践的教育从劳动密集型向技术密集型的制度转型,UGBS机制的产生在这一进程中有其逻辑必然性且揭示了这一转型独特的动力学机制。对此,文章提出了UGBS概念化这一理论命题,即明确四大行动主体及其交互关系。基于“大学—产业—政府”三螺旋结构这一概念框架,结合中国教育信息化发展历史对UGBS机制的产生与发展进行了回顾与阐释,实现了历史与逻辑的统一。文章从系统论和生态学视角出发,尝试对教育数字化进程中“UGBS机制究竟向何处去”这一问题进行了回答,提出教育变革的历史轨迹正从“布朗运动”向“莱维飞行”切换,UGBS机制未来需要应对教育创新之“莱维飞行”中潜藏的风险,教育数字化让教育生态系统进化始终处于混沌边缘,UGBS机制中蕴涵着教育数字化可持续发展的密码,在破解UGBS基因组密码的同时要谨防其发生负面的基因突变。

基于双螺旋式加热器的柔性MEMS流量传感器

针对传统流量传感器的量程限制,提出了一种基于双螺旋结构加热器的柔性基底微机电系统(MEMS)热式流量传感器。在基底上打出均匀通孔阵列以降低热传导损耗,两对测温电阻对称分布在加热器两侧,以获得较宽量程,在微小流量与大流量下均表现出较高灵敏度。采用基于惠斯通电桥的检测电路实现输出电压的测量,同时保持加热器与环境温度恒定温差200 K,对电阻自热进行补偿。传感器工作温度-100~400℃,量程为0~60 m/s;低流速下灵敏度约为12.75 V/(m·s^(-1)),分辨率可达0.001 mm/s,高流速下灵敏度约为1.4 mV/(m·s^(-1)),功耗低至1.3 mW。

基于多源数据和改进链路预测的新能源汽车技术机会研究

[研究目的]在绿色低碳发展的背景下,旨在识别新能源汽车领域的技术机会,为未来新能源汽车的技术研发与商业化方向提供借鉴参考,助力新能源汽车的发展。[研究方法]搜集反映新能源汽车领域基础研究、应用研究和商业化的多源数据,采用三螺旋模型,将基于改进链路预测方法得到的预测结果“节点链”进行融合对比分析,得到最终细化的新能源汽车技术机会。[研究结论]验证了基于多源数据融合思想和改进链路预测的方法识别新能源汽车技术机会的可行性。研究结果表明:新能源汽车未来技术机会主要集中在动态无线充电技术、磁悬浮技术与自动驾驶技术的结合;通过碳化硅材料等改进的驱动技术;通过光催化等改进的电池技术;制氢与车载储氢等。

科研诚信管理体系重构研究

科研诚信是科研管理方、科技主体在组织开展科学研究时所必须遵循的道德准则。文章基于我国科研诚信管理体系建设发展历程,从科研失信现状出发,探讨科研失信的成因与修复,梳理科研诚信治理现状,找出科研诚信治理困境,并结合合作治理理论、协同治理理论和“三螺旋”理论,提出了基于概念重构的科研方、管理方和监督方的科研诚信管理体系,以期为科研诚信监督和管理提供有益的借鉴和参考。

基于三螺旋理论的外贸类职教集团多方协同育人机制研究

职教集团作为当代职业教育中推进产教融合的重要模式,受到各个院校的重视,全国各地也在积极推进职教集团化办学。但历经30年的职教集团化办学,在发展中也遇到了种种问题,包括资金投入不足、组织松散、规章制度建设不完善等等。这些,都制约着今后职教集团的进一步发展以及集团整体育人质量的提升。本文以三螺旋理论为依据,通过分析全国,尤其是四川省职教集团的发展现状以及在协同育人中存在的问题,对于构建职教集团的多方协同育人机制提出了意见和建议,希望为四川省职业教育的发展提供有意义的借鉴。

中国共产党推进中华民族共同体意识成长的历史进程与基本经验

中华民族共同体意识是在客观历史进程与主观人为建构相互耦合的“双螺旋结构”中得以生成发展的。中国共产党自成立以来就有意识地推进中华民族共同体意识成长,成为引领这项事业发展的核心力量。运用文本分析、历史分析和规范分析方法梳理百余年来中国共产党推进中华民族共同体意识成长进程,可以将其划分为五个阶段,分别是建党到新中国成立时期从“自在”到“自觉”的初步探索、新中国成立到社会主义改造基本完成时期从“自觉”到“自为”的逐渐成熟、全面建设社会主义时期的曲折与徘徊、社会主义建设新时期的复苏与加速,以及新时代以来在“自为”之路全方位、多维度的成长与迈进。百余年来中国共产党推进中华民族共同体意识成长经验表明:必须坚持党的领导;中华民族愿意接受并坚决拥护党的领导。这是中国共产党推进中华民族共同体意识成长不断走向胜利的首要前提和根本原因。