A Novel Square-wave Pulse Rotation Modulation Strategy for Modular Multilevel Converters

悬浮直流电容电压的均衡问题是模块组合多电平变换器（modular multilevel converter,MMC）的关键问题之一。提出一种可实现MMC直流电容电压平衡的方波脉冲循环调制（square-wave pulse rotation modulation,SWPRM）策略,在保证合成的阶梯波输出波形不变的前提下,根据MMC的拓扑结构和工作原理,对传统方波脉冲列进行脉冲优化,并按照一定的次序和切换周期进行循环和判断反相调整,获得的循环方波脉冲列作为最终驱动脉冲用于实现对MMC的控制。实验结果表明,采用提出的方波脉冲循环调制策略无需任何电容电压控制措施,在较低开关频率下,实现了MMC各功率单元间有功能量的平均分配和直流电容电压的均衡。

Satellite Rotation Modulation Measurement System Based on Ultrasonic Motor

Rotation modulation technique is generally used to improve the performance of aviation and marine inertial navigation system.Considering of the performance requirements from current aerospace to MEMS micro-nano inertial device,this paper proposedrotary inertial device modulation technology application methods on the satellite.Firstly,taking the advantage ofultrasonic motor,like high resolution,fast response,electromagnetic compatibility,a lowmagnetic,high-precision and appropriate for use on satellite ultrasonic motor modulation turntable was developed.Then,through theoretical modeling and simulations,the rotation modulation technology was verified to improvethe precise of satellite attitude measurementeffectively,equivalent toimprove the accuracy of MEMS gyro over an order of magnitude.This work helpsachieve the application of rotation modulation technology in aerospace and acceleratethe promotion of the MEMS gyro in satellite attitude measurement.

Combined distal tibial rotational osteotomy and proximal growth plate modulation for treatment of infantile Blount's disease

Infantile Blount's disease is a condition that causes genu varum and internal tibial torsion. Treatment options include observation, orthotics, corrective osteotomy, elevation of the medial tibial plateau, resection of a physeal bar, lateral hemi-epiphysiodesis, and guided growth of the proximal tibial physis. Each of these treatment options has its disadvantages. Treating the coronal deformity alone(genu varum) will result in persistence of the internal tibial torsion(the axial deformity). In this report, we describe the combination of lateral growth modulation and distal tibial external rotation osteotomy to correct all the elements of the disease. This has not been described before for treatment of Blount's disease. Both coronal and axial deformities were corrected in this patient. We propose this combination(rather than the lateral growth modulation alone) as the method of treatment for early stages of Blount's disease as it corrects both elements of the disease and in the same time avoids the complications of proximal tibial osteotomy.

ROTATION CONSTELLATION FOR DIFFERENTIAL UNITARY SPACE-TIME MODULATION

A new constellation which is the multiplication of the rotation matrix and the diagonal matrix ac- cording to the number of transmitters is proposed to increase the diversity product, the key property to the performance of the differential unitary space-time modulation. Analyses and the simulation results show that the proposed constellation performs better and 2dB or more coding gain can be achieved over the traditional cyclic constellation.

A tightly coupled rotational SINS/CNS integrated navigation method for aircraft

Strapdown inertial navigation system(SINS)/celestial navigation system(CNS)integrated navigation is widely used to achieve long-time and high-precision autonomous navigation for aircraft.In general,SINS/CNS integrated navigation can be divided into two integrated modes:loosely coupled integrated navigation and tightly coupled integrated navigation.Because the loosely coupled SINS/CNS integrated system is only available in the condition of at least three stars,the latter one is becoming a research hotspot.One major challenge of SINS/CNS integrated navigation is obtaining a high-precision horizon reference.To solve this problem,an innovative tightly coupled rotational SINS/CNS integrated navigation method is proposed.In this method,the rotational SINS error equation in the navigation frame is used as the state model,and the starlight vector and star altitude are used as measurements.Semi-physical simulations are conducted to test the performance of this integrated method.Results show that this tightly coupled rotational SINS/CNS method has the best navigation accuracy compared with SINS,rotational SINS,and traditional tightly coupled SINS/CNS integrated navigation method.

Modified Omega-K algorithm for processing helicopter-borne frequency modulated continuous waveform rotating synthetic aperture radar data

With appropriate geometry configuration, helicopter- borne rotating synthetic aperture radar （ROSAR） can break through the limitations of monostatic synthetic aperture radar （SAR） on forward-looking imaging. With this capability, ROSAR has extensive potential applications, such as self-navigation and self-landing. Moreover, it has many advantages if combined with the frequency modulated continuous wave （FMCW） technology. A novel geometric configuration and an imaging algorithm for helicopter-borne FMCW-ROSAR are proposed. Firstly, by per- forming the equivalent phase center principle, the separated trans- mitting and receiving antenna system is equalized to the case of system configuration with antenna for both transmitting and receiving signals. Based on this, the accurate two-dimensional spectrum is obtained and the Doppler frequency shift effect in- duced by the continuous motion of the platform during the long pulse duration is compensated. Next, the impacts of the velocity approximation error on the imaging algorithm are analyzed in de- tail, and the system parameters selection and resolution analysis are presented. The well-focused SAR image is then obtained by using the improved Omega-K algorithm incorporating the accurate compensation method for the velocity approximation error. FJnally, correctness of the analysis and effectiveness of the proposed al- gorithm are demonstrated through simulation results.

Robust and high-speed rotation control in optical tweezers by using polarization synthesis based on heterodyne interference

The rotation control of particles in optical tweezers is often subject to the spin or orbit angular momentum induced optical torque,which is susceptible to the mechanical and morphological properties of individual particle.Here we report on a robust and high-speed rotation control in optical tweezers by using a novel linear polarization synthesis based on optical heterodyne interference between two circularly polarized lights with opposite handedness.The synthesized linear polarization can be rotated in a hopping-free scheme at arbitrary speed determined electronically by the heterodyne frequency between two laser fields.The experimental demonstration of a trapped vaterite particle in water shows that the precisely controlled rotation frequency of 300 Hz can be achieved.The proposed method will find promising applications in optically driven micro-gears,fluidic pumps and rotational micro-rheology.

Continuous rotation north-finding algorithm based on constrained adaptive Kalman filter

As an orientation measurement system,north-finder has been playing a significant role in both military and civilian fields of orientation and control.In this paper,to deal with drawbacks in the conventional north-finding systems,a dynamic strategy based on continuous rotation modulation to measure the rotational angular velocity of the earth is proposed.By modeling the dynamic error,optimizing the process constraint and estimating dynamic noise,a method combining delay compensation and hardware adjustment,and a constrained adaptive Kalman filter(CAKF)algorithm are designed for the north-finding strategy.According to simulation and experiments,the proposed algorithm can achieve the high-precision north-finding with robust and anti-noise performance.

An all-optical buffer based on polarization rotation in an EAM

A theoretical model of the refractive index changes of the TE and TM modes in an electro-absorption modulator （EAM） is deduced. The photon absorption and refractive index changes are analyzed numerically. The influence of pump intensity on the phase difference between the TE and TM modes is studied. The polarization rotation effect is obtained in the EAM, and a novel all-optical fiber loop buffer is designed.

Modeling of the influences of multiple modulated electron cyclotron current drive on NTMs in rotating plasma

In this work, physical models of neoclassical tearing modes （NTMs） including bootstrap current and multiple modulated electron cyclotron current drive model are applied. Based on the specific physical problems during the suppression of NTMs by driven current, this work compares the efficiency of continuous and modulated driven currents, and simulates the physical processes of multiple modulated driven currents on suppressing rotating magnetic island. It is found that when island rotates along the poloidal direction, the suppression ability of continuous driven current can be massively reduced due to current deposition outside the island separatrix and reverse deposition direction at the X point, which can be avoided by current drive modulation. Multiple current drive has a better suppressing effect than single current drive. This work gives realistic numerical simulations by optimizing the model and parameters based on the experiments, which could provide references for successful suppression of NTMs in future advanced tokamak such as international thermonuclear experimental reactor.

ANALYSIS OF UN-COINCIDE COORDINATE ERROR IN SINGLE-AXIS ROTATING FIBER OPTIC STRAP-DOWN INERTIAL NAVIGATION SYSTEM

The un-coincide coordinate error in the single-axis rotating fiber optic strap-down inertial navigation system（SINS） is analyzed. Firstly, a rotating modulation technology is presented for SINS. The method provides the enhanced property of SINS when using the same-leveled inertial measurement units. Then, the rotating struc- ture modification is derived and augmented to resolve the un-modulated error-accumulated problem. As the insuf- ficient machine processing, the horizontal and the vertical errors on the machine surface are inevitable, and the in- volved coordinates are difficult to get the exact coincident. So, two major kinds of coordinate situation are stud- ied. The equivalent error models on gyro and acceleration outputs are built for each situation, and the impact is analyzed for compensation. The part of attitude and position error models caused by the built angle-rate error is established to calculate the un-eoincident impact. Considering these conditions of different gyro accuracy and mo- tion states simultaneously, numerical simulations are implemented. Results indicate that the SINS modulation ac- curacy is seriously affected by the combined factors on gyro accuracy and motion conditions.

基于器件信息融合的双旋转惯导系统误差调制策略

目前,大型水面和水下载体一般安装两套旋转惯导系统(RINS),两套系统按相同的旋转调制策略独立运行,系统信息仅互为备份,缺乏有效融合。针对两台旋转惯导系统配置,开展基于器件信息深度融合的联合旋转调制策略研究,进一步提高系统精度。不改变单套系统结构和编排的前提下,优化经典的单轴4位置旋转方案,联合设计两套系统惯性测量单元(IMU)的旋转策略和转停时序,确保任一时刻有一台惯导处于转停状态,在时序上对转停状态下的惯性测量单元输出(陀螺仪和加速度计)信息进行融合,减小因惯性测量单元转动与刻度系数误差和安装误差的耦合效应。误差特性的理论分析验证了联合调制策略的优势。仿真结果表明:在典型误差作用下,采用联合旋转调制策略的系统定位误差,由单套旋转惯导系统精度的2.3 n mile/72 h提高到0.7 n mile/72 h。

旋转惯导姿态误差补偿方法分析

旋转惯导能够实现误差自补偿,从而提高系统导航精度。但旋转惯导中的旋转结构较为复杂,存在轴系的非正交误差、测角误差等,导致姿态输出随着旋转而发生波动,影响着惯导姿态解调输出的精度。针对惯导姿态误差补偿方法,选取4种常用的拟合补偿方法进行讨论,并结合实际采集数据,进行试验比对与分析,为后续工程应用提供参考。

光学陀螺旋转调制惯导系统及关键技术发展

面向长航时、高精度的自主导航技术需求,系统梳理光学陀螺旋转调制惯导系统的发展历程及关键技术现状具有重要的现实意义。首先,基于惯导系统误差特性,阐述了旋转调制技术的基本原理。其次,系统回顾和梳理欧美等西方国家旋转惯导系统发展历程,分析了系统发展演变后的技术逻辑,总结了我国旋转惯导系统的研制现状。最后,立足于提高系统自主导航精度,从旋转策略优化、误差标校、初始对准3个方面分析了旋转惯导系统需解决的关键技术及研究现状。在总结光学陀螺旋转调制惯导系统及关键技术发展基础上,针对后续旋转惯导系统研究提出了几点思考,为高精度自主导航技术研究提供参考。

AA3连续流动分析仪驱动马达带动转轴旋转模块设计及土壤中总氮测试

针对连续流动分析仪检测土壤中总氮时遇到的问题,研制了驱动马达带动转轴旋转模块.该模块可使混合的样品、试剂和空气保持在合适的温度区间进行中和反应,以利于后期利用连续流动分析仪在最优化条件下对样品进行检测分析,可将总氮的检出限从16.4µg/L降低至10.0µg/L,从而提高连续流动分析仪对样品的分析精度.

早期乳腺癌患者保乳术后行容积旋转调强放疗的剂量学参数与放射性肺炎的关系

目的探讨早期乳腺癌患者保乳术后行容积旋转调强放疗的剂量学参数与放射性肺炎(radiation pneumonitis,RP)的关系。方法选择2020年3月~2023年3月于本院住院治疗的140例保乳术后行容积旋转调强放疗的早期乳腺癌作为研究对象。根据放疗后是否发生RP将患者分为RP组(46例)和非RP组(94例)。所有患者中,1级RP有37例,2级RP有32例,3级RP有14例。比较两组患者的临床资料和剂量学参数。采用多元线性逐步回归肺功能指标与剂量学参数的相关性。采用多因素分析确定RP的独立风险预测因子。比较不同分级RP患者的基本资料及剂量学参数。采用广义混合效应模型分析剂量学参数与RP程度的关系。采用限制性立方样条模型分析剂量学参数与3级RP的剂量反应关系。结果两组患者在年龄、合并糖尿病、FEV1、MLD、患侧肺V_(5)、V_(10)、V_(20)和V30方面差异明显。年龄、糖尿病、FEV1、V_(5)和V_(20)均为影响患者RP发生的独立危险因素。3级RP患者年龄、合并糖尿病比例、FEV1<2 L比例、肺V_(5)和V_(20)明显升高(P<0.05)。广义混合效应模型结果显示,V_(5)和V_(20)与RP程度有关。限制性立方样条模型结果显示,V_(5)和V_(20)与3级RP的关联呈非线性的剂量反应关系(Pnon-linearity=0.426,0.537)。结论V_(5)和V_(20)是RP发生的独立危险因素,并且与患者RP程度具有一定相关性。临床应严格控制剂量-体积参数,以降低RP发生率。

复方斑蝥胶囊联合旋转容积调强技术对头颈部放疗生存期及血清XRCC1、XRCC3mRNA水平的影响

目的探究复方斑蝥胶囊联合旋转容积调强技术对头颈部放疗患者生存期及血清X线修复交错互补基因1(X-ray Repair Cross Complementing 1,XRCC1)、X线修复交错互补基因3(X-ray Repair Cross Complementing 3,XRCC3)信使核糖核酸(Messenger RNA,mRNA)水平的影响。方法选取2019年6月—2021年7月医院收治的头颈部肿瘤患者97例作为研究对象,根据治疗方法不同进行分组,对照组(48例)采用旋转容积调强技术结合放疗治疗,联合组(49例)在对照组基础上加用复方斑蝥胶囊治疗。观察比较临床疗效、中医证候积分、血清XRCC1及XRCC3mRNA水平、生存期、不良反应。结果联合组客观缓解率高于对照组(P<0.05),但疾病控制率与对照组比较差异无统计学意义(P>0.05)。联合组自汗、恶心呕吐、神疲乏力、食欲差、失眠、头晕眼花等得分低于对照组(P<0.05)。联合组血清XRCC1、XRCC3水平及外周血XRCC1、XRCC3 mRNA表达均低于对照组(P<0.05)。联合组无进展生存期和总生存期均高于对照组(P<0.05)。联合组不良反应发生率(34.69%,17/49)低于对照组不良反应发生率(72.92%,35/48)(P<0.05)。结论复方斑蝥胶囊联合旋转容积调强技术能改善头颈部放疗患者肿瘤客观缓解率,缓解临床症状,降低血清XRCC1、XRCC3mRNA水平,减少不良反应。

100 kHz弹光调制器多功能调制仿真

针对弹光调制器(photoelastic modulator,PEM)在超高速全偏振领域的测量问题,研究一种目标频率在100 kHz附近的圆型PEM,由弹光晶体和2个方位角相差45°的压电驱动器组成。通过理论计算弹光晶体谐振频率和压电驱动器振动频率,当二者频率达到一致时,PEM工作在谐振状态,此时PEM的调制效率达到最高。当PEM达到谐振状态并趋于稳定后,调节两压电驱动器驱动电压的幅值与相位,实现纯驻波模式和纯行波模式两种特殊调制,纯驻波模式可实现纯电控制下调制快轴的延迟量和方位角;纯行波模式可实现纯电控制下调制快轴以PEM谐振频率的半频速度高速旋转。最后,利用COMSOL有限元仿真模拟两种调制模式下PEM,验证两种调制状态下的PEM振型及其快轴方向,表明PEM可实现多功能弹光调制,为后续偏振测量提供理论支撑。

不同手术类型对乳腺癌放射治疗精确度的影响

目的研究乳腺癌改良的根治性乳房切除术(根治)、早期保乳手术(保乳)、假体植入3种手术类型对其放射治疗精确度的影响,为不同手术类型的患者制定个性化放疗方案。方法随机选择2023年2—7月就诊于厦门大学附属第一医院肿瘤放射治疗科行旋转调强治疗的乳腺癌放射治疗患者37例进行回顾性分析,其中乳腺根治患者13例,保乳患者11例,假体植入患者13例。每例患者除首次锥形束CT(Cone beam CT,CBCT)复位外,每5天在治疗前采集1次CBCT,并与定位图像进行配准,记录腹背(ventral-dorsal,VRT)、头脚(cranial-caudal,LNG)、左右(lateral,LAT)3个方向的误差值。共收集误差数据150组,其中根治61组,保乳38组,假体植入51组,并对误差进行分析。结果根治组在三维方向的摆位误差分别为:VRT[-1.80(-3.20,-0.20)]mm,LNG[-2.20(1.10,3.05)]mm,LAT[-3.30(-1.10,1.65)]mm,保乳组在三维方向的摆位误差分别为:VRT[-0.20(-1.03,1.03)]mm,LNG[1.40(-2.20,3.00)]mm,LAT[0.15(-3.05,2.90)]mm,假体植入组在三维方向的摆位误差分别为:VRT[-1.00(-3.00,0.70)]mm,LNG[-1.00(-3.00,1.80)]mm,LAT[0(-2.00,2.80)]mm,对3组数据进行K个独立样本的非参数检验和事后多重比较显示,根治组和保乳组在VRT方向比较,差异有统计学意义(P<0.05)。3组在LNG,LAT方向上比较,差异无统计学意义(P>0.05)。3组不同手术类型在三维方向上的计划靶区(planning target volume,PTV)边界分别为根治组(4.18,6.19,7.52 mm),保乳组(4.71,6.53,8.01mm),假体植入组(6.17,7.53,6.29 mm)。结论不同手术类型对乳腺癌放射治疗精确度影响不同,在VRT方向上根治组的摆位误差大于保乳组,可根据不同的手术类型个性化选择固定方式以提高患者的摆位精确度。除此之外,每个肿瘤中心可根据不同的手术类型计算适合自己中心的PTV外扩范围以给予临床医生建议。

基于双惯导协同的误差参数估计与融合算法

针对无外界参考信息的双惯导系统长期使用后系统参数发生变化导致导航精度降低,且系统间缺少信息融合的问题,提出了一种同等精度双惯导协同误差估计与信息融合算法。首先以两套旋转式惯导间相对速度误差与位置误差作为观测量,建立包含陀螺和加速度计零偏的导航误差模型。然后分析了不同转序下各状态量的可观测性,采用Kalman滤波对各参数进行有效估计,估计完成后对双惯导系统进行误差补偿及信息融合。仿真结果表明,所提算法对陀螺零偏估计精度优于0.002(°)/h,加速度计零偏估计精度优于4μg,在抑制误差发散的同时,提高了旋转式惯导导航精度。