New kind of Hermite-Gaussian-like optical vortex generated by cross phase

We propose a new kind of optical vortex called the Hermite-Gaussian-like optical vortex(HGOV)inspired by the cross phase(CP).Theoretically,we investigate how the CP is decoupled from the phase of a cylindrical lens.We also investigate the propagation characteristics of an HGOV,which has a Hermite-Gaussian-like intensity distribution but still retains the orbital angular momentum.F urthermore,we derive the Fresnel diffraction integral of an HGOV and study the purity at infinity.Besides,we show a novel function of the self-measurement of the HGOV.Finally,we show that we can change the relative positions of singularities and the direction of an HGOV precisely,which facilitates applications in optical micro manipulation.

Device Length Dependency of Cross Gain Modulation and Cross Phase Modulation in Semiconductor Optical Amplifier

The cross gain modulation, the cross phase modulation and their recovery time in the SOAs with the various lengths were experimentally investigated. It was found that these values strongly depended on the device length.

Effects of walk-off on cross-phase modulation induced modulation instability in an optical fibre with high-order dispersion

This paper investigates the effects of walk-off among optical pulses on cross-phase modulation induced modulation instability in the normal dispersion region of an optical fibre with high-order dispersion. The results indicate that, in the case of high-order dispersion, the walk-off effect takes on new characteristics and will influence considerably the shape, position and especially the number of the spectral regions of the gain spectra of modulation instability. Not only the group-velocity mismatch, but also the difference of the third-order dispersion of two optical waves will alter the gain spectra of modulation instability but in different ways. Depending on the values of the walk-off parameters, the number of the spectral regions may increase from two to at most four, and the spectral shape and position may change too.

Cross-phase modulation instability in optical fibres with exponential saturable nonlinearity and high-order dispersion

Utilizing the linear-stability analysis, this paper analytically investigates and calculates the condition and gain spectra of cross-phase modulation instability in optical fibres in the ease of exponential saturable nonlinearity and high-order dispersion. The results show that, the modulation instability characteristics here are similar to those of conventional saturable nonlinearity and Kerr nonlinearity. That is to say, when the fourth-order dispersion has the same sign as that of the second-order one, a new gain spectral region called the second one which is far away from the zero point may appear. The existence of the exponential saturable nonlinearity will make the spectral width as well as the peak gain of every spectral region increase with the input powers before decrease. Namely, for every spectral regime, this may lead to a unique value of peak gain and spectral width for two different input powers. In comparison with the case of conventional saturable nonlinearity, however, when the other parameters are the same, the variations of the spectral width and the peak gain with the input powers will be faster in case of exponential saturable nonlinearity.

Low Noise Phase CMOS Quadrature VCO with Superharmonic Coupling Using Cross-Couple Pair

This paper aims to introduce a quadrature VCO (voltage control oscillator) which applies superharmonic coupling. The presented quadrature VCO is suitable to be used, both with 2 × subharmonic mixers, as well as 4×subharmonic mixers. It would be impossible to avoid the presence of harmonics in CMOS VCO circuits. These harmonics are in general, undesirable signals which tend to accompany the desired fundamental signal. There are common-mode nodes (similar to those in the two source nodes in a cross-coupled VCO) in deferential VCO at which higher-order harmonics are present while the fundamental is absent in essence. We can make use of these second-order harmonics which are present at the common-mode nodes of two VCO in order to implement a quadrature connection between the fundamental outputs. The technique through which this is done is called superharmonic coupling. This CMOS quadrature VCO which applies active superharmonic coupling puts an excellent performance in show, with an output power –0.942 dBm for fundamental and –9.751 dBm for subharmonic, phase noise –107.2 dBc/Hz for fundamental and –114.8 dBc/Hz at a 1MHz offset. All of circuit applied are designed and simulated by ADS, 2008.

Linearized Phase Detector Zero Crossing DPLL Performance Evaluation in Faded Mobile Channels

Zero Crossing Digital Phase Locked Loop with Arc Sine block (AS-ZCDPLL) is used to linearize the phase difference detection, and enhance the loop performance. The loop has faster acquisition, less steady state phase error, and wider locking range compared to the conventional ZCDPLL. This work presents a Zero Crossing Digital Phase Locked Loop with Arc Sine block (ZCDPLL-AS). The performance of the loop is analyzed under mobile faded channel conditions. The mobile channel is assumed to be two path fading channel corrupted by additive white Gaussian noise (AWGM). It is shown that for a constant filter gain, the frequency spread has no effect on the steady state phase error variance when the loop is subjected to a phase step. For a frequency step and under the same conditions, the effect on phase error is minimal.

Predicting Net Cross-Shore Total Load Transport: A Phase-Averaging, Quasi-Steady Approach Incorporating Undertow Contribution

Wave shapes that induce velocity skewness and acceleration asymmetry are usually responsible for onshore sediment transport, whereas undertow and bottom slope effect normally contribute to offshore sediment transport. By incorporating these counteracting driving forces in a phase-averaged manner, the theoretically-based quasi-steady formula of Wang （2007） is modified to predict the magnitude and direction of net cross-shore total load transport under the coaction of wave and current. The predictions show an excellent agreement with the measurement data on medium and fine sand collected by Dohmen-Janssen and Hanes （2002） and Schretlen （2012） in a full-scale wave flume at the Coastal Research Centre in Hannover, Germany. The modified formula can predict the net onshore transport of fine sand in sheet flows. In particular, it can predict the net offshore transport of medium sand in rippled beds through enlarged bed roughness, as well as the net offshore transport of fine-to-coarse sand in sheet flows with the aid of a new criterion to judge the occurrence of net offshore transport.

两桥臂交叉解耦不平衡控制策略研究

由于非不平衡控制策略中没有考虑线电压和相电流的相角差,造成三相电网的有功、无功电流无法完全补偿。为了解决这一问题,根据电压电流相角差,推导出单相补偿器中无功参考补偿电流与负载电流的关系,提出一种两桥臂交叉解耦不平衡控制策略,利用多变量滤波器和交叉解耦双复系数滤波器优化锁相环,精确锁定三相不平衡电网的电压频率和相位,对2个单相背靠背变换器的无功电流分别控制,进而利用两桥臂变换器补偿三相不平衡无功。实验结果验证了所提两桥臂交叉解耦不平衡控制策略,可抑制三相有功不平衡及补偿三相不平衡无功,将三相电流的不平衡度从150.0%降低至2.6%,三相电网功率因数从0.257提升至0.997,减少了三相无功补偿器的开关管个数。

血小板自身抗体在血小板输注无效中的临床意义

目的观察血小板自身抗体与同种抗体对血小板交叉配型难易程度及输注效果的影响。方法选择2021年7月—2023年9月在本实验室完成血小板抗体鉴定的106例血小板输注无效(PTR)患者,根据血小板抗体类型将患者分为两组,20例自身抗体阳性患者为观察组,86例同种抗体阳性患者为对照组。比较两组患者配型相合次数百分率、配型相合供者百分率、输注交叉配型相合血小板及随机血小板的24 h血小板计数增加指数(CCI)值及输注有效率的差异,并对观察组自身抗体变化情况进行追踪。结果观察组的配型相合次数百分率及配型相合供者百分率均高于对照组(P<0.05)。观察组患者输注交叉配型相合血小板与随机血小板的24 h CCI值及输注有效率均无显著性差异(P>0.05),对照组患者输注交叉配型相合血小板的24 h CCI值及输注有效率均高于输注随机血小板(P<0.001),对照组患者输注交叉配型相合血小板后24 h CCI值及输注有效率比观察组高(P<0.05),对照组和观察组输注随机血小板后24 h CCI值及输注有效率无显著性差异(P>0.05)。观察组多数患者的自身抗体强度呈下降趋势。结论血小板自身抗体对血小板交叉配型难易程度及输注效果的影响比同种抗体小。血小板自身抗体强度随时间推移呈现逐渐下降乃至消失的规律。在临床实践中,对于自身抗体患者的治疗,应当首先查找病因,并进行针对性治疗,如果需要输注血小板,可以选择输注随机血小板。

药物临床研究阶段申办者和生产场地变更研究六:临床研究阶段申办者和生产场地跨境变更的风险分析

目的:通过对临床研究阶段申办者、生产场地发生跨境变更时的风险变化进行分析,为申办者和生产场地的跨境变更管理提供参考。方法:基于申办者和生产场地不同组合情形的初始风险评价结果和采取风险管控措施后的风险再评价结果,比较分析不同组合情形之间发生变更时变更前后的“风险指数水平”变化。结果与结论:基于初始风险评价结果,有两种变更情形的风险指数水平在变更后较变更前降低;基于风险再评价结果,有四种变更情形的风险指数水平在变更后较变更前降低。

Flow patterns and their transition characteristics of the air-water two-phase flow in a horizontal pipe with a sudden-changed cross-section area

Flow patterns in upstream and downstream straight tubes of sudden-changed areas in a horizontal straight pipe were experimentally examined. Both sudden-expansion cross-section (SECS) and sudden-contraction cross-section (SCCS) were investigated. The flow pattern maps upstream and downstream were delineated and compared with those in straight tubes with uniform cross-sections. The effects of the SECS and SCCS on flow patterns were discussed and analyzed. Furthermore, flow pattern transition mechanisms resulting in occurrences of different flow patterns were simply discussed and some transition criteria for the flow pattern transitions were deduced by using the non-dimensionlized analysis method.

基于多光子叠加态的交叉相位调制耦合参数测量

继纠缠之后,粒子间相互作用已成为量子增强的重要资源.在不利用纠缠资源的前提下,已有研究工作利用单光子叠加态与相干态的相互作用实现了精度为海森堡极限的参数测量,然而海森堡极限并不是这个相互作用模型的测量精度极限.为了得到更高的测量精度,将单光子叠加态替换为多光子叠加态,在弱测量框架下对信号光量子态进行后选择与量子态筛选.将单光子叠加态替换为多光子叠加态,能为测量结果带来全方位提升.提出基于多光子叠加态的交叉相位调制耦合参数测量的物理方案,该物理方案具有搭建难度低及操作简单的优点.

激光外差探测阵列互相关相干累积法

针对粗糙目标导致本振光与信号光波前失配这一技术难题,提出一种基于序列移位与互相关的用于检测微弱外差信号的相干累积法。该方法利用阵列探测器的阵列信号进行互相关运算,将外差信号频谱幅值作为目标函数,快速准确地估计最佳序列偏移量和计算相位调整量,搭建了一套基于高速摄像机阵列探测器的光外差探测系统。仿真分析和实验结果表明,该方法应用于主动光外差探测领域时对相位补偿的精确度更高,信号处理时间可提高到毫秒量级。

在远程三方之间建立高保真的量子通信信道

量子通信是利用量子力学原理,把微观的物质特性运用到通信技术上,在高速传输和高可靠保密通信等方面具有显著优势,成为当今通信技术领域的研究热点之一。量子通信系统的中心环节就是远程各方之间建立稳定、可靠、安全的量子信道。本方案基于弱交叉克尔非线性的量子非破坏(QND)光子数解析检测、交叉相位调制(XPM)技术和线性光学元件以及单比特旋转操作可高保真地制备出远程三粒子纠缠Greenberger-Horne-Zeilinger(GHZ)态,从而作为实现远程三方之间量子通信的信道。当前方案远程制备出来的GHZ态总成功率理论上是确定性的,而保真度原则上近似接近单位1。然而,在实际远距离量子通信过程中,难免会受到环境噪声的影响,从而导致保真度的降低。本方案通过以牺牲成功概率为代价,实现远程三方之间直接建立高保真度的GHZ态的纠缠共享。使用基本线性光学元件,在仅引入弱的交叉克尔非线性,且不需要额外添加辅助光子的情况下,就可以获取高保真度的GHZ纯态,证实了本方案在实际应用中具有简便性、可实现性以及资源利用率高的显著优势。

煤系沥青包覆再生石墨微观构造及电化学性能

石墨负极材料易在石墨层间与电解液发生共嵌入导致石墨层膨胀、粉化脱落,严重影响石墨负极材料的循环稳定性。利用沥青对石墨负极进行包覆,形成不定型碳层包覆的“核壳”结构,可减少石墨层的膨胀脱落,提高石墨负极材料的电化学性能。以中温煤焦油沥青为原料,通过空气氧化和聚合交联制备得到高结焦值、高软化点的包覆沥青。通过液相包覆方法,考察了对再生石墨负极的包覆性能。采用X射线衍射(XRD)、拉曼光谱(Raman)、氮气吸附、扫描电镜(SEM)和透射电镜(TEM)等方法分析了再生石墨包覆形貌与界面微观结构变化,并对材料电化学性能进行了测试。结果表明,沥青包覆可有效完善再生石墨微观构造。随着沥青包覆量的增加,石墨表面缺陷减少,比表面积和孔容降低;炭化后包覆界面形成不定型碳层,包覆界面无序度随沥青包覆量的增加而升高。不定型碳包覆层的形成显著提高了石墨负极性能,包覆12%沥青的再生石墨比容量达到450 mA·h/g,相比未包覆石墨提升140 mA·h/g;沥青包覆石墨负极首次库伦效率增加11.5%,并且循环稳定性获得改善;在5 A·h下比容量提高至285 mA·h/g,相比未包覆再生石墨提高242.8 mA·h/g,倍率性能突出。

交叉迁移联合肌电生物反馈干预对亚急性期脑卒中患者腕背伸功能的影响

目的:观察交叉迁移联合肌电生物反馈干预对亚急性期脑卒中患者腕背伸功能的影响。方法:将45例亚急性期脑卒中患者随机分为交叉迁移组、肌电生物反馈组、联合组,每组各15例。3组患者均接受常规康复训练,交叉迁移组在此基础上进行交叉迁移治疗,肌电生物反馈组在此基础上进行肌电生物反馈治疗,联合组在此基础上进行交叉迁移联合肌电生物反馈治疗。以上每组治疗需持续6周,并于治疗前、治疗后采用主动关节活动度(active joint range of motion,AROM)、徒手肌力评定(manual muscle test,MMT)、上肢Fugl-Meyer评分(FMA-UE)、改良Barthel指数(modified Barthel index,MBI)对患者腕背伸功能、上肢运动功能及日常生活活动能力进行评定。结果:治疗前,3组患者的FMA-UE评分、腕背伸AROM及肌力评分、MBI评分比较均无显著性差异(P>0.05)。治疗6周后,3组患者的FMA-UE评分、腕背伸AROM及肌力评分、MBI评分与治疗前相比均明显提高(P<0.05)。其中,联合组与交叉迁移组、肌电生物反馈组相比,除MBI评分比较无显著性差异(P>0.05)外,其他指标评分比较均有显著性差异(P<0.05),而交叉迁移组和肌电生物反馈组各项指标评分比较均无显著性差异(P>0.05)。结论:交叉迁移联合肌电生物反馈干预在改善亚急性期脑卒中患者腕背伸功能、上肢运动功能及日常生活活动能力方面优于单一的交叉迁移或肌电生物反馈疗法。

视听工作记忆的相位同步与跨频耦合研究

为了深入了解视听工作记忆中的神经机制和节律耦合规律,采集了视听工作记忆任务脑电数据,通过时频分析确定关键节律及核心电极,并使用多变量模式分析确定关键时间段。theta相位同步在记忆呈现期至关重要,其中额颞叶同步参与听觉记忆,额顶叶同步参与视觉记忆,而theta和alpha的跨频耦合只在特定记忆模态的相关脑区有显著增强。工作记忆任务相关脑区通过远端theta同步协调中央执行功能,alpha同步协调记忆存储缓冲功能,theta-alpha耦合整合不同模态功能间的信息,揭示了视听模态工作记忆的部分神经机制。

基于冲突相位组的自动驾驶交叉口行人过街控制方法

【目的】在无信号控制的自动驾驶环境下,自动驾驶车辆的通行轨迹将与过街行人产生大量冲突,如何利用交通控制手段使行人安全通过交叉口,并避免对自动驾驶车辆的通行造成较大的干扰,是亟待解决的关键问题。【方法】本文提出一种基于冲突相位组的自动驾驶交叉口行人过街控制方法,将到达交叉口的车辆流向分为4个冲突相位组,在各相位组内单独分配通行时间,基于冲突相位组对自动驾驶车辆和行人过街的通行时间进行建模;在穿插式通行模式的基础上,使用行人信号灯保障行人过街需求,建立考虑行人二次过街的自动驾驶交叉口交通控制模型。模型以交叉口各流向需求量与实际交通量乘积之和最大为目标,以各流向允许车辆通行的时间比例和行人信号灯状态为决策变量,综合考虑交通流量、行人和车辆通行权等约束,建立混合整数线性规划模型(mixed-integer linear program,MILP),该控制模型可为各流向的车辆和行人分配通行权。【结果】本文模型的车均延误较定时控制方案的降低26.74%,较单次过街模型的降低11.53%,人均延误较定时控制方案的降低51.66%,较单次过街模型的降低36.20%。这表明本文模型能有效提升交叉口的通行效率。【结论】本文模型能根据自动驾驶车辆和行人的通行需求,对交叉口时空通行权进行分配,有效保障行人过街安全。

基于几何相位的高透射型太赫兹超表面设计

文中提出一种基于几何相位的透射型超表面,通过对超表面单元结构的设计和排布实现了对入射圆极化波的波前任意操控和太赫兹涡旋波的产生。该超表面单元由典型的“三明治”型结构,即金属-介质-金属结构组成,顶层和底层金属图案均是由“C”型和矩形组成。利用几何相位原理,在工作频点下通过旋转金属结构对其相位进行调控,同时交叉极化透射幅度较高(>0.9)。通过对单元结构进行旋转编码,可以形成用于产生异常偏折现象、不同拓扑荷数涡旋光束的编码超表面。仿真结果表明,在0.63 THz处,设计的编码超表面能够对电磁波进行良好的调控,产生折射角为±50.1°和30°的异常折射现象,拓扑荷数l=±1两种模态的涡旋波束,在激光雷达和太赫兹大容量通信等领域具有潜在的应用价值。

一种大功率圆极化交叉对称阵子天线

为了满足大功率反射面天线的馈源设计要求,文章设计了一种大功率圆极化交叉对称阵子天线,其工作频率在1.19GHz~1.285GHz,天线整体由交叉对称阵子和开槽线巴伦组成。通过开槽线巴伦实现平衡-非平衡馈电。为了实现圆极化,通过改变对称阵子结构,在对称阵子臂相邻90°处增添一对阵子臂,形成交叉对称阵子,并通过调整阵子臂的长度,使其实现90°自相移结构,并最终实现圆极化,由于天线整体均为金属,使得天线可以承受更高的功率。该天线在1.19GHz~1.285GHz频带内电压驻波比(votage standing wave ratio,VSWR)<1.5,圆极化轴比<3dB,实测结果表明,实测和仿真结果基本一致,天线在该频段内实现了较好的圆极化特性。