Influence of acceleration stage electrode voltage on the performance of double-stage Hall effect thruster with adjustable zero magnetic point

The configuration of electrode voltage and zero magnetic point position has a significant impact on the performance of the double-stage Hall effect thruster. A 2D-3V model is established based on the two-magnetic peak type double-stage Hall thruster configuration, and a particle-in-cell simulation is carried out to investigate the influences of both acceleration electrode voltage value and zero magnetic point position on the thruster discharge characteristics and performances.The results indicate that increasing the acceleration voltage leads to a larger potential drop in the acceleration stage, allowing ions to gain higher energy, while electrons are easily absorbed by the intermediate electrode, resulting in a decrease in the anode current and ionization rate. When the acceleration voltage reaches 500 V, the thrust and efficiency are maximized, resulting in a 15%increase in efficiency. After the acceleration voltage exceeds 500 V, a potential barrier forms within the channel, leading to a decrease in thruster efficiency. Further study shows that as the second zero magnetic point moves towards the outlet of the channel, more electrons easily traverse the zero magnetic field region, participating in the ionization. The increase in the ionization rate leads to a gradual enhancement in both thrust and efficiency.

A Cross-Sectional Study on the Impact of Operation Triple Zero (OTZ) Program on Viral Load Suppression amongst Members of the Adolescent Club in 68 Nigerian Army Reference Hospital Yaba Lagos, Nigeria

Background: In Nigeria, adolescents and young people (AYP) aged 10 - 24, comprise 22.3% of the population and with HIV prevalence of 3.5%. The AYP living with HIV enrolled at the 68 NARHY, Lagos reflects the national challenges with poor viral suppression. The OTZ program aligns with the UNAIDS 95-95-95 goals. It seeks to empower AYPLHIV to be in charge of their treatment and commit to triple zero outcomeszero missed appointments, zero missed drugs, and zero viral loads. The purpose of the study was to assess the impact of the OTZ program on viral load suppression among members of the adolescent club in 68 NARHY, Lagos. Method: A cross-sectional retrospective study to evaluate the impact of the OTZ program on the viral load of 53 AYP enrolled in the OTZ program between March 2019 to December 2019 was analyzed. The Percentage of viral load suppression before enrollment compared with 6 and 12 months after enrollment into the OTZ program. The AYP is grouped into 10 - 14, 15 - 19, and 20 - 24 years. Activities conducted were peer driven monthly meetings with the AYP during which the adolescents interacted on issues relating to improving their treatment outcomes, healthcare workers reviewed their clinical status, viral load result, provider peer counseling, and caregivers engagement to support adherence to medication and ARV refills. Results: Before OTZ, 81% aged 10 - 14 years, 75% aged 15 - 19 years, and 25% aged 20 - 24 years were virally suppressed (VL less than 1000 copies/ml). Six months after enrollment, 94% were virally suppressed95% aged 10 - 14 years, 96% aged 15 - 19 years, and 66% aged 20-24 years. Twelve months after enrollment, 96% of AYP were virally suppressed100% aged 10-14 years, 93% aged 15 - 19 years, and 100% aged 20 - 24 years. Males viral load (VL) suppression improved from 79% to 96% and 92%, while females VL suppression improved from 69% to 93% and 100% at 6 and 12 months respectively. Conclusion: The OTZ activities contributed to improved viral load suppression in the AYP of the facility.

NORMALITY AND THE NUMBER OF ZEROS

In this paper,we study normal families of meromorphic functions.By using the idea in[11],we obtain some normality criteria for families of meromorphic functions that concern the number of zeros of the differential polynomial,which extends the related result of Li,and Chen et al..An example is given to show that the hypothesis on the zeros of a(z)is necessary.

On Zero Dynamics and Controllable Cyber-Attacks in Cyber-Physical Systems and Dynamic Coding Schemes as Their Countermeasures

In this paper, we study stealthy cyber-attacks on actuators of cyber-physical systems(CPS), namely zero dynamics and controllable attacks. In particular, under certain assumptions, we investigate and propose conditions under which one can execute zero dynamics and controllable attacks in the CPS. The above conditions are derived based on the Markov parameters of the CPS and elements of the system observability matrix. Consequently, in addition to outlining the number of required actuators to be attacked, these conditions provide one with the minimum system knowledge needed to perform zero dynamics and controllable cyber-attacks. As a countermeasure against the above stealthy cyber-attacks, we develop a dynamic coding scheme that increases the minimum number of the CPS required actuators to carry out zero dynamics and controllable cyber-attacks to its maximum possible value. It is shown that if at least one secure input channel exists, the proposed dynamic coding scheme can prevent adversaries from executing the zero dynamics and controllable attacks even if they have complete knowledge of the coding system. Finally, two illustrative numerical case studies are provided to demonstrate the effectiveness and capabilities of our derived conditions and proposed methodologies.

Vector magnetometry in zero bias magnetic field using nitrogen-vacancy ensembles

The application of the vector magnetometry based on nitrogen-vacancy(NV)ensembles has been widely investigatedin multiple areas.It has the superiority of high sensitivity and high stability in ambient conditions with microscale spatialresolution.However,a bias magnetic field is necessary to fully separate the resonance lines of optically detected magneticresonance(ODMR)spectrum of NV ensembles.This brings disturbances in samples being detected and limits the rangeof application.Here,we demonstrate a method of vector magnetometry in zero bias magnetic field using NV ensembles.By utilizing the anisotropy property of fluorescence excited from NV centers,we analyzed the ODMR spectrum of NVensembles under various polarized angles of excitation laser in zero bias magnetic field with a quantitative numerical modeland reconstructed the magnetic field vector.The minimum magnetic field modulus that can be resolved accurately is downto~0.64 G theoretically depending on the ODMR spectral line width(1.8 MHz),and~2 G experimentally due to noisesin fluorescence signals and errors in calibration.By using 13C purified and low nitrogen concentration diamond combinedwith improving calibration of unknown parameters,the ODMR spectral line width can be further decreased below 0.5 MHz,corresponding to~0.18 G minimum resolvable magnetic field modulus.

Research on Data Tampering Prevention Method for ATC Network Based on Zero Trust

The traditional air traffic control information sharing data has weak security characteristics of personal privacy data and poor effect,which is easy to leads to the problem that the data is usurped.Starting from the application of the ATC(automatic train control)network,this paper focuses on the zero trust and zero trust access strategy and the tamper-proof method of information-sharing network data.Through the improvement of ATC’s zero trust physical layer authentication and network data distributed feature differentiation calculation,this paper reconstructs the personal privacy scope authentication structure and designs a tamper-proof method of ATC’s information sharing on the Internet.From the single management authority to the unified management of data units,the systematic algorithm improvement of shared network data tamper prevention method is realized,and RDTP(Reliable Data Transfer Protocol)is selected in the network data of information sharing resources to realize the effectiveness of tamper prevention of air traffic control data during transmission.The results show that this method can reasonably avoid the tampering of information sharing on the Internet,maintain the security factors of air traffic control information sharing on the Internet,and the Central Processing Unit(CPU)utilization rate is only 4.64%,which effectively increases the performance of air traffic control data comprehensive security protection system.

Algorithm for Visualization of Zero Divisor Graphs of the Ring ℤn Using MAPLE Coding

This research investigates the comparative efficacy of generating zero divisor graphs (ZDGs) of the ring of integers ℤn modulo n using MAPLE algorithm. Zero divisor graphs, pivotal in the study of ring theory, depict relationships between elements of a ring that multiply to zero. The paper explores the development and implementation of algorithms in MAPLE for constructing these ZDGs. The comparative study aims to discern the strengths, limitations, and computational efficiency of different MAPLE algorithms for creating zero divisor graphs offering insights for mathematicians, researchers, and computational enthusiasts involved in ring theory and mathematical computations.

From Standard Policy-Based Zero Trust to Absolute Zero Trust (AZT): A Quantum Leap to Q-Day Security

Cybercrime is projected to cost a whopping $23.8 Trillion by 2027. This is essentially because there’s no computer network that’s not vulnerable. Fool-proof cybersecurity of personal data in a connected computer is considered practically impossible. The advent of quantum computers (QC) will worsen cybersecurity. QC will be a boon for data-intensive industries by drastically reducing the computing time from years to minutes. But QC will render our current cryptography vulnerable to quantum attacks, breaking nearly all modern cryptographic systems. Before QCs with sufficient qubits arrive, we must be ready with quantum-safe strategies to protect our ICT infrastructures. Post-quantum cryptography (PQC) is being aggressively pursued worldwide as a defence from the potential Q-day threat. NIST (National Institute of Standards and Technology), in a rigorous process, tested 82 PQC schemes, 80 of which failed after the final round in 2022. Recently the remaining two PQCs were also cracked by a Swedish and a French team of cryptographers, placing NIST’s PQC standardization process in serious jeopardy. With all the NIST-evaluated PQCs failing, there’s an urgent need to explore alternate strategies. Although cybersecurity heavily relies on cryptography, recent evidence indicates that it can indeed transcend beyond encryption using Zero Vulnerability Computing (ZVC) technology. ZVC is an encryption-agnostic absolute zero trust (AZT) approach that can potentially render computers quantum resistant by banning all third-party permissions, a root cause of most vulnerabilities. Unachievable in legacy systems, AZT is pursued by an experienced consortium of European partners to build compact, solid-state devices that are robust, resilient, energy-efficient, and with zero attack surface, rendering them resistant to malware and future Q-Day threats.

On Zero Translation in News Discourse

In the context of globalization,zero translation words are more and more frequently used in news discourse.This article aims to explore the reasons for the frequent use of zero translation words in news discourse and their impact on news discourse from the perspectives of translation studies and journalism and communication studies.

基于MIKE ZERO 2020的郁江贵港河段一维水质模型

基于MIKE ZERO 2020软件中的HD水动力学模块和AD对流扩散模块,建立郁江贵港市河段的水文、水质信息耦合模型,对郁江贵港河段的水位、流量以及污染物在水体中迁移扩散衰减情况进行了模拟分析。根据郁江近年来的水文资料对模型进行率定并验证。将该模型应用于2023年6月21日~7月6日的洪水过程,结果表明,所建立的模型在率定和验证及应用期间模拟效果均表现良好,模拟精度高。充分证明该模型适用于模拟郁江贵港河段的水文、水质信息变化特征,为提高贵港市防洪、水情预报及水污染预测提供了重要的技术支撑。

A Critical Analysis of the Chinese Translation of“Zero Report”-Towards the Standardization of Terminology from the Perspective of Global Health Communication

The term“zero report,”an essential component of public health surveillance systems,is used to denote the reporting of zero cases of a specified disease during a given period.Its Chinese translation,“零报告”,has often been misinterpreted by the public as“no report”or“absence of report,”resulting in confusion and misinformation.This paper examines the linguistic and cultural factors contributing to this misinterpretation,exploring the semantic discrepancies between“zero”in English and“零”in Chinese.Using a mixed-methods approach that combines theoretical analysis and empirical survey data,the paper highlights the challenges of translating technical terminology across linguistic and cultural contexts.It also provides recommendations for improving the translation of“zero report”and other public health terms to ensure clear global communication.

虚拟桌面与零客户端在实验室管理中的研究应用——VMware Horizon View与Dell Wyse Zero Client的融合研究

我校计算机实验室至今仍在使用2006年开发的机房计费管理系统,此系统的刷卡终端安装于实验室外,常年运行在恶劣的户外环境中,因此故障频发,无法长时间正常运行。面对上述问题,我校教学环境部利用当前已趋于成熟的虚拟桌面技术,让机房计费管理系统的刷卡终端能够稳定地运行在恶劣的户外环境中,并且能够便利地对其进行管理和维护。

基于强化学习与Zero-DCE的图像增强方法

在深度学习技术不断演进的背景下,图像增强技术在图像处理领域备受瞩目。尽管传统的处理方法在改善图像质量方面有所成就,但对于高动态范围、高噪声、低对比度等复杂场景的图像处理需求,其效果通常难以令人满意。采用了创新性的图像增强方法,将图像分解为照明和反射两部分,以实现更为出色的增强效果。综合运用Retinex、Zero-DCE和强化学习技术,提升了图像质量和可视性,在处理复杂场景中展现了显著的效果。通过强化学习和组合损失函数,使得图像增强效果更显著。基于Retinex理论的实现方式进一步加强了整体算法的性能。此外,结合Zero-DCE的方法,通过深度曲线估计照明和反射两部分,有效区分了不同场景的图像增强需求。

光电系统中的自归零复合轴稳瞄系统

针对传统复合轴稳瞄系统子轴运动范围较小、易积分饱和导致系统失效的问题,提出自归零复合轴稳瞄系统。在剖析传统复合轴稳瞄系统子轴易积分饱和致系统失效原由的基础上,提出主轴据强度函数随动子轴的自归零复合轴稳瞄系统,通过直观展示、理论分析及数学仿真软件仿真其在避免子轴积分饱和及增强系统抗扰特性方面的可行性及优势,并搭建试验平台开展试验验证。测试结果表明,在低频段,自归零复合轴稳瞄系统可在保证子轴扰动抑制能力的同时,大幅度增强系统的主轴扰动抑制能力,使主轴误差维持在较小值,避免子轴限位饱和。由此表明自归零复合轴稳瞄系统的可行性,及其在避免子轴限位饱和、维持系统稳定性方面的优势。

基于动态相量的并联逆变器并网系统超高次谐波零序环流特性分析

为研究共交直流侧母线的并联逆变器并网系统中超高次谐波零序环流特征分量及边带分量的特性,通过分析各逆变器的开关状态研究系统中零序环流的流通路径,并建立零序环流等效电路;利用动态相量法建立计及逆变器间载波相位差的超高次谐波零序环流分析模型;以该模型为基础,分析并联逆变器并网系统的超高次谐波零序环流特征分量特性和边带分量特性。最后,通过仿真验证了理论分析的正确性。

基于注意力机制和能量函数的动作识别算法

针对零样本动作识别(ZSAR)算法的框架缺乏结构性指导的问题,以基于能量的模型(EBM)指导框架设计,提出基于注意力机制和能量函数的动作识别算法(ARAAE)。首先,为了得到EBM的输入,设计了光流加3D卷积(C3D)架构的组合以提取视觉特征,从而达到空间去冗余的效果;其次,将视觉Transformer(ViT)用于视觉特征的提取以减少时间冗余,同时利用ViT配合光流加C3D架构的组合以减少空间冗余,从而获得非冗余视觉空间;最后,为度量视觉空间和语义空间的相关性,实现能量评分评估机制,设计联合损失函数来进行优化实验。采用6个经典ZSAR算法及近年文献里的算法在两个数据集HMDB51和UCF101进行实验的结果表明:相较于CAGE(Coupling Adversarial Graph Embedding)、Bi-dir GAN(Bi-directional Generative Adversarial Network)和ETSAN(Energy-based Temporal Summarized Attentive Network)等算法,在平均分组的HMDB51数据集上,ARAAE平均识别准确率提升至(22.1±1.8)%,均明显优于对比算法;在平均分组的UCF101数据集上,ARAAE的平均识别准确率提升至(22.4±1.6)%,略优于对比算法;在以81/20为分割方式的UCF101数据集上,ARAAE的平均识别准确率提升至(40.2±2.6)%,均大于对比算法。可见,ARAAE在ZSAR中能有效提高识别性能。

基于UTXO模型区块链的众包物流可信身份认证模型

针对现有集中式众包物流平台中用户身份数据存储与管理存在的隐私泄露和篡改问题,提出一种基于UTXO模型区块链的众包物流可信身份认证模型.该模型包括利用区块链技术实现身份注册、身份验证、身份撤销及身份认证.针对链上存储用户隐私数据风险的问题,采用混合加解密方案对链上个人信息做安全存储与分享;针对平台认证用户身份的问题,采用可信身份凭证以零知识证明方式登录众包物流平台.对身份信息以及认证进行安全性分析,并将该方法与LIU方法、LI方法的安全性能进行了对比.在Python3.9环境下完成试验,进行了身份信息加密和零知识身份认证测试分析.结果表明该方案的认证时延和处理事务能力均优于现有的SHAO方案.

零序互感对距离保护的影响与自适应补偿方法

针对一起同塔双回线发生跨线接地故障时欠范围纵联距离保护拒动事件,本文分析同塔双回线单相接地故障与跨线接地故障的特征,以及零序互感对接地距离保护的影响,得出零序互感带来的附加阻抗是引起接地距离保护范围缩小并导致欠范围纵联距离保护拒动的根本原因。为避免零序互感对同塔双回线接地距离保护范围的影响,须对零序互感进行补偿,因此本文提出一种自适应补偿方法,通过引入邻线零序电流,结合本线零序电流方向和相电流方向,实现对零序互感的自适应补偿。最后,利用实时数字仿真系统对本文所提补偿方法进行评估,仿真结果证明了所提方法的有效性。

基于半桥三电平LLC谐振变换器的混合控制策略研究

半桥三电平LLC谐振变换器具有体积小、开关器件少、开关器件耐压高等优势,已逐渐应用于直流充电模块后级为动力电池充电。针对传统变频调制(PFM)策略与移相调制(PSM)策略无法实现宽输出电压范围的问题进行分析,提出一种宽增益范围的移相-变频(PSM-PFM)混合控制策略。通过搭建一台功率为600 W、输出电压为20~60 V的实验样机进行验证。实验结果表明,所提控制策略相比单一调制策略具有更宽的增益,进而可实现宽输出电压范围,能够为动力电池提供稳定、宽范围且可调的充电电压,并实现开关管零电压开通。

Zero-P颈椎前路融合治疗颈椎病8例临床观察

目的观察探讨Zero-P在颈椎病治疗颈椎前路融合的作用与效果。方法选取佛山市第一人民医院骨科收治的Zero-P前路融合治疗的颈椎病患者8例,进行临床资料分析。结果 8例平均术程2 h,平均出血量80 mL。术后3 d咽部吞咽疼痛2例,肩背痛3例,无1例产生吞咽异物感及吞咽困难,无1例出现颈前内植物并发症。平均椎间融合时间4个月。结论 Zero-P可独立应用于颈椎前路椎间融合固定术,其手术操作简便,术后病者咽喉异物感和吞咽困难显著降低,减少椎前植入物引致并发症。