Magnetic sensitivity technology based on microwave modulation of solid state spin system NV center

In view of the low resolution and accuracy of traditional magnetometer,a method of microwave frequency modulation technology based on nitrogen-vacancy(NV)center in diamond for magnetic detection was proposed.The magnetometer studied can reduce the frequency noise of system and improve the magnetic sensitivity by microwave frequency modulation.Firstly,ESR spectra by sweeping the microwave frequency was obtained.Further,the microwave frequency modulated was gained through the mixed high-frequency sinusoidal modulation signal generated by signal generator.In addition,the frequency through the lock-in amplifier was locked,and the signal which was proportional to the first derivative of the spectrum was obtained.The experimental results show that the sensitivity of magnetic field detection can reach 17.628 nT/Hz based on microwave frequency modulation technology.The method realizes high resolution and sensitivity for magnetic field detection.

Fabrication of 32 Gb/s Electroabsorption Modulated Distributed Feedback Lasers by Selective Area Growth Technology

A 32 Gb/s monolithically integrated electroabsorption modulated laser is fabricated by selective area growth technology. The threshold current of the device is below 13mA. The output power exceeds 10mW at 0V bias when the injection current of the distributed feedback laser is 100mA at 25℃. The side mode suppression ratio is over 50 dB. A 32Gb/s eye diagram is measured with a 3.SVpp nonreturn-to-zero pseudorandom modulation signal at -2.3 V bias. A clearly opening eyediagram with a dynamic extinction ratio of 8.01 dB is obtained.

A new tracking error detection method using amplitude difference detection for signal waveform modulation multi-level discs

The sub-land/sub-pit affects the characteristic of the tracking error signal which is generated by the conventional differential phase detection （DPD） method in the signal waveform modulation multi-level （SWML） read-only disc. To solve this problem, this paper proposes a new tracking error detection method using amplitude difference. Based on the diffraction theory, the amplitude difference is proportional to the tracking error and is feasible to be used for obtaining the off-track information. The experimental system of the amplitude difference detection method is developed. The experimental results show that the tracking error signal derived from the new method has better performance in uniformity and signal-to-noise ratio than that derived from the conventional DPD method in the SWML read-only disc.

Controlling the light wavefront through a scattering medium based on direct digital frequency synthesis technology

Phase modulation is a crucial step when the frequency-based wavefront optimization technique is exploited to measure the optical transmission matrix(TM) of a scattering medium. We report a simple but powerful method, direct digital frequency synthesis(DDS) technology to modulate the phase front of the laser and measure the TM. By judiciously modulating the phase front of a He–Ne laser beam, we experimentally generate a high quality focus at any targeted location through a 2 mm thick 120 grit ground glass diffuser, which is commercially used in laser display and laser holographic display for improving brightness uniformity and reducing speckle. The signal to noise ratio(SNR) of the clear round focus is 50 and the size is about 44 μm. Our study will open up new avenues for enhancing light energy delivery to the optical engine in laser TV to lower the power consumption, phase compensation to reduce the speckle noise, and controlling the lasing threshold in random lasers.

Intrusion Detection System with Remote Signalling for Vehicles Using an Arduino Controller and Radio-Frequency Technology

Malicious activities or policy violations have been a concern for the past years. For example, many people have been victims of robbery on vehicles. A conceptual diagram of an Intrusion Detection System (IDS) [1] [2] for vehicles with remote signaling using an Arduino controller and radio-frequency technology is proposed in this paper. To address malicious activities on vehicles, two aspects are considered here, namely: notifier and detector. Firstly, an object-oriented C module that puts on and off a controller (installed inside the vehicle) and an anti-theft electronic editing that powered using an alternator and supported by a back-up battery are implemented. Secondly, a magnetic intrusion sensor, controlled by a proximity detector using radio-frequency technology, has been installed on each vehicle door. To enable IDS, a user needs to activate the monitoring system when leaving their vehicle. This is done using a remote system. In case the user does not activate the monitoring system while leaving the vehicle, a 5-meter-proximity detector will automatically lock the system and set off the monitoring system whenever the user is outside the detection zone. The detection zone is a 5-meter radius area centered at the controller. Here, monitoring consists of geolocating any intruders within the detection zone. This means, if any of the vehicle doors is opened while the system is still locked, the controller will activate the vehicle alarm for a few seconds, thereafter send an SMS notification to the owner. The system automatically unlocks as soon as the proximity detector is within the detection zone. The contribution of this paper, as compared to other similar work, is to reinforce the electronic implementation of IDS.

Chinese Telemetry Technology under Fast Development

The history of the development of Chinese telemetry is introduced in the paper. The new telemetry ground station and the new onboard space telemetry system, with the idea of systematic design and the specification, are described.

Modulation Index Estimation of Frequency and Phase Modulated Signals

Modulation index estimation is important in the demodulation and recognition of Angle Modulation (AM) signals which include Frequency Modulation (FM) and Phase Modulation (PM) signals. In this paper, we firstly analyzed the AM signals with baseband modulation types, such as monotone, PSK, FSK, in the time and frequency domain. Then, we established a unified mathematical representation for the AM signals. Finally, we derived a blind estimation algorithm for the modulation index without using any prior knowledge. Simulation results verify the capabilities of the proposed algorithm.

A KIND OF PAPR REDUCTION METHOD BASED ON PRUNING WPM AND PTS TECHNOLOGY

Wavelet packet multicarrier system gains widespread concern because of its better resistance performance to Inter-Symbol Interference (ISI) and Inter-Carrier Interference (ICI), as well as the higher spectrum efficiency. However, multicarrier system has a high Peak to Average Power Ratio (PAPR), which will lead to many problems such as lower system performance. In order to solve the problem, a kind of PAPR reduction method based on pruning Wavelet Packet Modulation (WPM) and Partial Transmit Sequences (PTS) technology is proposed in this paper, through proper pruning of the full-tree structure of wavelet packet modulation in the PTS technology to reduce the number of nodes in the system, and finally improve the reduction effect of PAPR. Simulation results show that when Complementary Cumulative Distribution Function (CCDF) is 10 -3 , PTS based on pruning WPM compared with PTS technique and pruning technique has improved about 1 dB and 1.5 dB, which will not affect the system's Bit Error Rate (BER) performance in the wavelet packet multicarrier system.

Research on Feature Extraction of Composite Pseudocode Phase Modulation-Carrier Frequency Modulation Signal Based on PWD Transform

The identification features of composite pseudocode phase modulation and carry frequency modulation signal include pseudocode and modulation frequency. In this paper,PWD is used to extract these features. First,the feature of pseudocode is extracted using the amplitude output of PWD and the correlation filter technology. Then the feature of frequency modulation is extracted by way of PWD analysis on the signal processed by anti-phase operation according to the extracted feature of pseudo code,i.e. position information of changed abruptly point of phase. The simulation result shows that both the features of frequency modulation and phase change position caused by the pseudocode phase modulation can be extracted effectively for SNR=3 dB.

一种L波段300W GaN脉冲功率模块

随着第三代半导体GaN器件技术的不断发展,GaN高电子迁移率晶体管(HEMT)在电子系统中逐步得到了广泛应用。研制了一款小型化L波段300 W GaN脉冲功率模块。研发了满足高压脉冲工作条件的GaN HEMT芯片,采用负载牵引技术进行了器件大信号阻抗参数提取,并以此为基础设计了小型化匹配网络进行阻抗变换。基于高压驱动芯片和开关器件芯片设计了小型化高压脉冲调制电路。测试结果表明,在工作频率990~1130 MHz、工作电压50 V、脉冲宽度100μs、占空比10%下,功率模块脉冲输出功率大于300 W,功率附加效率大于53%,功率增益大于38 dB。功率模块尺寸为30 mm×30 mm×8 mm。

基于半导体桥和含能材料的信息储存介质自毁模块研究

针对高安全等级信息储存介质硬件层面的防护,开展了基于半导体桥(SCB)和含能材料的低驱动能量自毁模块的研究.建立了SCB等离子体发火、能量传递、含能材料点火的数学模型并完成了理论计算,利用COMSOL搭建SCB多物理场仿真模型并校核其性能,搭建了试验平台并进行SCB与含能材料发火性能测试的试验.仿真和试验结果表明:含能自毁模块具有优良的发火性能,能在5 V充电电压的激励下,起爆SCB桥区并使桥区温度能在18μs内达到2700 K,从而激发0.43 mg叠氮化铜在50μs内起爆产生爆轰波.含能自毁模块能够完成能量的传递并摧毁目标信息储存介质,有效避免信息储存介质关键信息被窃取,保证了信息储存介质的安全性.

光伏组件技术进步的“干中学”与“研中学”效应研究

光伏产业是我国具有全球竞争优势的战略性新兴产业,推动其高质量发展是实现“3060”双碳目标的重要手段之一。采用双因素学习曲线模型,参照索罗余值法测度从2015—2020年光伏组件技术进步的“干中学”效应和“研中学”效应。其中,由“干中学”效应导致的光伏组件成本下降约为0.85元/瓦,贡献率为42.40%;由“研中学”效应导致的成本下降约为1.07元/瓦,贡献率为57.60%。进一步对光伏组件“干中学”效应和“研中学”效应的驱动因素进行研究。“干中学”效应方面,从供给侧和需求侧两个维度采用文献分析法讨论了驱动光伏组件产量增加的因素;“研中学”效应方面,采用知识生产函数分析研发资本投入和人力投入对光伏组件技术进步速度的影响。结果表明,光伏组件研发资本投入存在边际报酬递减的现象,而研发人力投入的边际报酬是递增的。在此基础上,分析研究结果的政策启示。

基于薄膜铌酸锂的微波光子雷达芯片

微波光子雷达拥有分辨率高、处理速度快、同时多波段、多功能等优势,在航天系统中具有广阔的应用前景。为了满足航天应用对雷达系统体积、质量和功耗的严格要求,集成化已经成为微波光子雷达的重要发展方向。介绍了一款基于薄膜铌酸锂的微波光子雷达芯片,利用该芯片实现了雷达发射信号倍频产生和回波信号去斜接收,并对距离天线不同位置的目标进行了测距实验,得到的测量距离与实际距离基本相同,两者之间的误差小于4 mm。

基于Style 3D针织运动装虚拟设计与应用

基于Style 3D虚拟服装试衣软件,通过对虚拟试衣技术现状的分析,以针织运动装作为虚拟试衣对象,从四个部分进行展开,包含人体建模,版片的三维排布与缝合,运动装面料仿真与试穿效果展示,以及驳样改款与模块组合。借助于三维面料扫描技术获取面料材质纹理和相关辅料配件,进一步丰富针织运动装的装饰效果。3D快速驳样改款和虚拟展示能有效地优化设计过程,针织运动装模块组合模拟应用适应快时尚节奏下改款搭配的需求,根据现有版型快速驳样改款亦是对传统设计与展示模式的一种突破。

Reviewer Locator模块在科技期刊中的应用实践与发展前景——以《中国肺癌杂志》为例

科技期刊作为科技传播的重要力量,其对重要科研成果的发布速度影响着科学技术的传播效力,而编辑工作效率直接决定稿件发表周期,提高编辑工作效率是科技期刊发展的推进器。为此,从同行评议审稿人储备和遴选方面入手,重点阐述如何准确高效地多维度遴选优质审稿人,归纳并探析Reviewer Locator模块在科技期刊办刊工作中的实际应用经验,助力出版业实现质量更好、效率更高的发展。

嵌入式机房多功能模块智能监控系统设计

为充分提高大型机房智能化运维能力,及时排除各种异常情况,实现高精度、低功耗的系统设计目标;提出基于嵌入式的机房多功能模块智能监控系统设计方法;设计针对机房空间的传感信号采集层、数据传输层、后台监控层的多层系统架构;硬件结构设计了用户登录模块、传感器运行模块、数据记录模块和监控显示模块,4个功能模块在多层架构下工作;软件部分通过数据传输程序连接终端设备与云计算中心,利用数据处理程序完成功能模块参数设置,完成嵌入式机房运行数据自动监控,针对系统的功耗问题,设计了微结构级功耗模型,降低系统功耗;实验结果表明:所设计系统容错率在80%以上,数据采集精度高,当浓度超过100 ppm时,自动对烟雾超标情况启动报警装置;可以实时响应接入设备,及时获取预警信息,功耗低,平均响应时间均在2.8 s以下,实现嵌入式机房自动智能监控。

基于人工智能技术的计算机网络在线教学平台设计

为提高在线教学的效率和质量,文中基于人工智能技术设计了计算机网络在线教学平台。首先,设计了平台的总体框架,包括平台管理、教师、学生等模块以及集成性的人工智能模块,其中人工智能模块涵盖智能学习资源推荐系统、自动评分系统和个性化学习路径规划模块。同时,对用户界面的设计进行了细致的探讨。在系统测试部分,对平台进行了全面的性能测试。结果表明,该平台在提高教学互动性、个性化学习体验及教学资源利用率方面表现出色,验证了其在现代教育中的应用价值和潜力。文中不仅为在线教育提供了一种新的智能化解决方案,也为教育技术的未来发展提供了重要的理论和实践参考。

基于项目+模块的模拟电子技术研究性教学建构

模拟电子技术是电类专业一门重要的专业基础必修课,具有工程性、实践性强等特点。在课时少、内容多且知识难的教学现状下,课程组以项目为依托、以模块为载体,深入剖析当前教学中的痛点,立足于“OBE”理念和“新工科”建设标准,以产教融合、科教融合和立德树人为纲转变教学中心,以“两性一度”为领重构课程教学内容、创新教学方法和教学组织形式,以工程专业认证为导向建构多元化教学体系和课程考核形式,注重课程目标达成情况和持续改进。深挖课程典型思政案例,无缝嵌入,隐形育人。通过上述举措,将抽象的知识形象化、复杂理论简单化、虚拟仿真实践化,实现“知识+能力+思政”的全面育人。

南海深水FPSO模块支墩设计与分析

针对中国南海海况恶劣,浮式生产储卸油装置(Floating Production Storage and Offloading,FPSO)在南海服役多年后,少数支墩由于建造工艺出现裂纹问题,以南海某深水FPSO为研究对象,对常用箱式支墩形式进行改进优化设计。运用有限元方法对箱式模块支墩和改进后的丰字形模块支墩与十字交叉带裙边支墩进行评估,对不同支墩形式进行强度分析、变形分析和疲劳分析,并对不同支墩的工艺进行综合对比,结合工程实践和有限元计算,给出支墩推荐设计方案。结果表明,优化后的十字交叉带裙边支墩结构强度和疲劳均优于箱式支墩,同时还具有便于加工组装的特点,最终选定十字交叉带裙边支墩方案。

水声通信及网络技术综述

水声通信(UAC)及网络技术在海洋环境监测、商业领域和军事领域等诸多方面发挥着重要作用,关心海洋、认识海洋、经略海洋离不开水声通信及网络技术的发展。该文对水声通信技术和水声通信网络(UACN)进行综述,首先回顾了水声通信技术和水声通信网络的发展,总结了水声信道的特点。然后,对于水声通信技术中的非相干调制技术、相干调制技术以及以应用需求为导向的新型通信技术进行陈述。随后,对于水声通信网络中数据链路层媒介接入控制协议、网络层的路由协议和跨层设计进行分类探讨。最后,对目前水声通信及网络技术的不足进行总结,并且对未来水声通信及网络技术的发展进行展望。