基于声光信号的单站式闪电三维通道定位系统

目前基于雷声的三维定位系统多停留在实验阶段,从业务化运行的角度考虑,改进了单站式闪电三维定位系统的麦克风阵列,设计了定位算法,利用该系统采集了2014年夏季南京地区的部分闪电数据,并从计算耗时的角度对三维通道实时定位的可行性进行了研究。结果表明,基于声光信号的单站式闪电三维通道定位系统可重构闪电的三维通道;对连续的雷声信号进行分帧,帧长取0.03 s时,声源定位点可描绘出清晰的闪电主通道;采用分组保存和处理闪电声光信号的方法,可实现实时定位,当一组数据的保存时间为50 s时,计算耗时为46.507 s。

界面三维扩散通道与富锂锰基的协同效应研究

富锂锰基正极材料具有诸多优点,但是其低锂离子电导率和高扩散势垒严重影响其倍率性能。提出了快离子导体磷酸钛铝锂表面包覆改性策略,分析了富锂锰基正极材料与磷酸钛铝锂包覆层的协同效应。结果表明:在700℃煅烧5 h,包覆量为3%(质量分数)Li_(1.3)Ti_(1.7)Al_(0.3)(PO_(4))_(3)的Li-[Li_(0.2)Mn_(0.54)Ni_(0.13)Co_(0.13)]O_(2)具有最佳的性能,在100次循环后,放电比容量为226.5 mAh/g,保持率为89.7%。其优异的电化学性能可归因于包覆层提供三维锂离子扩散通道,减小了电极-电解液界面迁移阻抗。

基于声光信号的雷电通道三维定位算法研究

提出了一种利用雷电声光信号进行雷电三维通道定位方法。根据雷电现象发生时,流光每发展一步都会有对应的声光信号产生的原理,利用光信号极值之间的时间间隔,对相应的雷声信号进行不定长时间窗的分段,然后利用相关函数法和声光信号到达的时间差求出每段数据对应的声源三维坐标,最终获取雷电的三维通道。该方法克服了以往算法中利用定长时间窗对雷声信号进行分段带来的雷电通道定位误差。实验结果表明该方法具有一定的可行性。

三维立体定向下软通道穿刺置管引流术与小骨窗开颅治疗高血压脑出血的对比分析

目的对三维立体定向下软通道穿刺置管引流术治疗高血压脑出血与小骨窗开颅血肿清除术式治疗的效果进行对比探究。方法回顾性分析我院自2012年5月-2016年7月内住院接受治疗的高血压脑出血患者90例,根据手术方式不同分为观察组(45例)和对照组(45例),观察组行三维立体定向下软通道置管穿刺引流术治疗,对照组行小骨窗开颅血肿清除术,观察两组治疗效果以及总住院时间和治疗总费用。结果观察组SSS评分、ADL评分均较对照组优,差异显著,具有统计学意义(p<0.054);治疗3个月后,观察组病死率低于对照组,差异存在显著性(p<0.05);观察组总住院时间以及平均住院费用均优于对照组,有统计学差异(p<0.05)。结论在高血压脑出血临床治疗上应用三维立体软通道进行治疗,定位准确、血肿清除彻底,术后病死率降低,治疗费用低,值得基层医院推广应用。

三维多通道传感响应的二阶校正新策略及其新应用

二阶张量校正（Second—order tensorial calibration）是基于三维多通道传感等响应系统、能对复杂未知样中待测多组分进行直接快速同时定量分析的化学计量学策略和方法。它虽为单元校正、多元校正的拓展，但有独特的“二阶优势（Second—order advantage）”：它即使有未知干扰或基体共存，也能对未知样中待测多组分进行直接快速同时定量分析，且该策略具有简便、经济等优点。它与现代分析化学量测手段相结合，

多通道三维界面软件边缘模糊缺陷自动修复方法

针对传统方法修复时间慢的问题,提出多通道三维界面软件边缘模糊缺陷自动修复方法。采用正交缺陷分类方法识别边缘模糊缺陷,再提出混合交叉策略,使得搜索方向偏离适应度低的解,在此基础上,设计多通道三维界面软件边缘模糊缺陷自动修复流程,通过补丁生成、变异规则修改、编译、补丁应用和补丁验证等步骤,修复多通道三维界面软件边缘模糊缺陷。由此,完成多通道三维界面软件边缘模糊缺陷自动修复方法的设计。最后,进入实验部分,给出6个软件程序,测试2个方法的修复时间,实验结果表明,所提方法的平均确认时间在9.2 s左右,传统方法的平均确认时间在12.2 s左右,说明所提方法的修复时间更高,且符合设计需求。

一次上行闪电中先导二维和三维发展特征的差异

基于高时空分辨率的广州高建筑物雷电观测站双站(观测点1和观测点2)同步观测资料,对比分析2019年4月20日05:12(世界时)发生在广州塔上的一次上行闪电的先导二维和三维发展特征。分析表明:该上行闪电可三维重建的上行先导通道发展长度约为5.4 km,是对应两个观测点二维通道长度的1.5倍和1.38倍;由观测点1的高速摄像记录分析得到的上行先导二维发展速率变化范围为1.8×10^(4)~4.5×10^(5)m·s^(-1)(平均值为1.8×10^(5)m·s^(-1));对应的上行先导三维发展速率变化范围为3.8×10^(4)~7.2×10^(5)m·s^(-1)(平均值为2.8×10^(5)m·s^(-1));三维和二维发展速率之比变化范围为1~4.7,平均值为1.5;上行先导始发后10 ms内,三维与二维发展速率的变化趋势大致相同,均随高度增加而逐渐加快;10 ms后二维发展速率明显降低,平均值仅为10 ms内的42%,且随时间变化较小。而10 ms后的三维发展速率平均值为10 ms内的77%,随时间呈明显的不规则波动变化;先导通道与观测点间的距离以及通道发展方向与观测点视线方向的夹角是造成上行先导二维和三维发展速率差异的主要因素。

三维立体微流控芯片制作方法研究

目的通过对三维立体通道模具的制作进行研究,以制备能生产高效低价均一载药微液滴的三维立体微流控芯片。方法试验过程中对芯片模具基底材料,曝光时间、刻蚀时间对三维立体微流控芯片模具制作的影响,及聚二甲基硅氧烷(PDMS)的配方和固化温度对微流控芯片成型的影响进行了系统地研究,获得最优化工艺参数,制备出最适合于产生载药微液滴的微流控芯片。结果有机玻璃板综合性能最优,可作为芯片模具基底材料;刻蚀时间、曝光时间随通道厚度的增加而增长。对于层数较少的掩膜(如1、2层)最佳曝光时间为10、15 s。一般采用大于临界时间,使所需通道稍微过曝。以PDMS为材料注塑成型制备出理想的三维通道微流控芯片,并采用自动进样泵于各通道注入不同液相来高速制备尺寸可控的均一微液滴。结论该模具制备方法快速、价格低廉,克服了大多数三维微流控芯片模具制作工艺复杂、成本高昂等缺点,PDMS注塑成型技术操作简单,可满足快速生成粒径理想、尺寸均一化、重现性好的载药微液滴的要求。

MoS_(2)空心球/石墨烯气凝胶电极储锂性能研究

以氧化石墨烯(GO)悬浮液为原料,经凝胶、冷冻干燥,再经过热处理将GO还原为还原氧化石墨烯(rGO),采用自组装方法制备出三维石墨烯气凝胶(3D GA)。通过调节GO悬浮液的浓度可以调控3D GA的空间结构,通过改变热处理温度和时间可以控制3D GA的表面缺陷密度。在3D GA合成过程中MoS_(2)多孔纳米空心球(MoS_(2)-PHS)原位生长在3D GA框架表面制备了3D MoS_(2)/GA复合电极。MoS_(2)/GA复合电极在0.2 A·g-1电流密度下显示出1396 mAh·g-1初始放电比容量,在200次循环后仍然具有高达1162 mAh·g-1的可逆比容量,复合电极优异的电化学性能归结于其独特的三维通道石墨烯框架可以改善GA通道的电子传输,促进GA通道的锂离子扩散,缩短了扩散途径,GA稳定的结构可有效缓解循环过程中MoS_(2)体积变化引起的应力。

Quantum Secure Direct Communication by Using Three-Dimensional Hyperentanglement

We propose two schemes for realizing quantum secure direct communication (QSDC)by using a set ofordered two-photon three-dimensional hyperentangled states entangled in two degrees of freedom (DOFs)as quantuminformation channels.In the first scheme,the photons from Bob to Alice are transmitted only once.After insuring thesecurity of the quantum channels,Bob encodes the secret message on his photons.Then Alice performs single-photontwo-DOF Bell bases measurements on her photons.This scheme has better security than former QSDC protocols.In thesecond scheme,Bob transmits photons to Alice twice.After insuring the security of the quantum channels,Bob encodesthe secret message on his photons.Then Alice performs two-photon Bell bases measurements on each DOF.The schemehas more information capacity than former QSDC protocols.

Three-Dimensional Bursting Phenomena in Meander Channel

Experiments were conducted in a U-shaped open-channel flume with the intention of investigating the bursting phenomena in the meander channel. The experimental results of the secondary flow fields and the Reynolds shear stress distributions show that the velocity and velocity fluctuation in the transverse direction are not negligible. Moreover, the bursting process is investigated using the three-dimensional quadrant analysis, which is more accurate than using the traditional two-dimensional quadrant analysis for the meandering channel. It is obtained from the experimental results that the internal group of events occurs more frequently than the external group, particularly the internal ejection and internal sweep events. In addition, the transition probabilities of the movements, which are defined as the changes of events from the current situation to the next situation in a time series, show that the stable organizations of events are the most possible movements, whereas the cross organizations of events have the least possible movements.

Tracking Submicron Particles in Microchannel Flow by Microscopic Holography

Three-dimensional tracking of submicron particles in flows in a micro-channel was carried out using in-line holographic microscopy.A fixed single 0.5 μm fluorescent particle was identified and isolated from dust particles or overlapped particle pair using the laser induced fluorescent(LIF) method.Then in-line microscopic holograms of the fixed single particle were obtained at different positions on the optical axis,i.e.the defocus distances.The holograms of the single particle were used as the model templates with the known defocus distances.The particles in the in-line microscopic holograms of flow in the microchannel were then identified and located to obtain their two-dimensional positions.The defocus distances of those particles were determined by matching each hologram pattern to one of the model templates obtained in the single particle test.Finally the three-dimensional position and velocity of each particle were obtained.

Numerical analysis on thermal regime in double-loop channel inductor

In order to investigate the temperature distribution, a three-dimensional finite element model （FEM） was developed to simulate the temperature regime in the channels of double-loop inductor, and the simulated results were compared with experimental data from low load trials of a 400 kW inductor. The results of numerical simulations, such as the temperature and Joule heating rate, show reasonable correlation with experimental data. The results indicate that Joule heating rate and the temperature reach the maximum at the comers and the minimum at the centre of the cross-section area. The temperature difference between the inlet and outlet is in an inverse proportion to mass transport. Joule heating rate and the temperature are directly proportional to power frequency. It is concluded that mass transport and power frequency play a critical role in determining the temperature regime and Joule heating rate, the relative permeability of the magnetic core shows no significant influence on temperature regime and Joule heating rate, when the relative permeability varies from 5 000 to 10 000.

Assessment of Levator Hiatus by 3D Ultrasound Volume Contrast Imaging in Normal Nulliparas

The ability of 3D ultrasound volume contrast imaging in C-plane （VCI-C） in the assessment of female levator hiatus was analyzed in eighty normal nullipaxas. Interoperator variability in levator hiatus measurements was analyzed. The comparison of the axial image of magnetic resonance imaging （MRI） and C-plane image of volume contrast imaging （VCI） in thirty normal nulliparas was also done. It shows that VCI-C can clearly demonstrate the structure and accurately quantitates the size of the levator hiatus. It is reliable, convenient and without contraindication in assessment of female levator hiatus. The technology opens up entirely new modality for assessing female pelvic floor.

Controlled teleportation of an unknown 3D two-particle state via 3D partially entangled states

A scheme is presented to realize the controlled teleportation of an unknown three dimensional(3D) two-particle state by using a non-maximally entangled two-particle state and a non-maximally entangled three-particle state in the 3D space as the quantum channels,and one of the particles in the channels is used as the controlled particle.Analysis shows that when the quantum channels are of maximal entanglement,namely the channels are composed of a 3D Bell state and a 3D GHZ state,the total success probability of the controlled teleportation can reach 1.And this scheme can be expanded to control the teleportation of an unknown D-dimensional two-particle state.

Study on coupled 3D seepage and stress fields of the complex channel project

Seepage is a vital reason that may bring many adverse consequences such as subsidence,inclination and fracture to the channel,and is harmful to the safety and stability of the channel.Thus,a 3D visualization model is established for the engineering geological information of the research channel section by using NURBS-TIN-BRep hybrid data structure.Coupled with the VOF(volume of fluid)method,the N-S(Navier-Stokes)equations are applied to seepage simulation of the research channel section.Then the stability of the channel is studied coupled with the seepage simulation results,to comprehensively analyze the stress and displacement conditions of the channel under the impact of different factors such as seepage and underground goafs.The results of this study illustrate that the channel seepage has great influence on its stability,especially on the displacement field:it will lead to a significant sedimentation to the foundation.Therefore,during the practical construction,it is suggested that the certain part of the channel should be reinforced and effective seepage control measures should be taken.

Design and calibration of a new high-definition three-dimensional laparoscopic system

We present a high-definition （HD） 3D laparoscopic system including a dual channel optical system, two cameras, a camera control unit （CCU）, and an HD 3D monitor. This laparoscopic system is capable of outputting dual high-definition videos and providing vivid 3D images. A modified pinhole camera model is used for camera calibration and a new method of depth measurement to improve precision. The average error of depth measurement measured by experiment （about 1.13 mm） was small in proportion to the large range in distance of the system （10-150 mm）. The new method is applicable to any calibrated binocular vision system.

Heat transfer and flow characteristics in a channel with one corrugated wall

The present study numerically investigates the characteristics of three-dimensional turbulent flow and heat transfer in the channel with one corrugated wall heated with constant temperature by means of large eddy simulation.The corrugated wall is sinusoidal in the streamwise and spanwise directions.The Reynolds number in terms of bulk velocity and channel half-height is fixed at 2800 and the wave amplitude to wavelength ratio is varied in the rangeα/λ=0.01,0.02,0.04 in the streamwise direction andα/λ=0.01,0.02,0.04 in the spanwise direction.The results show that flow separation bubbles appear and near-wall streamwise vortices are generated with larger population in the upslope region of the bottom wall as wave amplitude increases.Compared with flat wall,the corrugated geometry increases the pressure coefficient and decreases the friction coefficient on the corrugated wall,and consequently increases the total drag coefficient owing to the increase of pressure coefficient,as expected,the heat transfer is higher.The waves in the spanwise direction converge the vortices into the trough along the streamwise direction and push them away from the bottom wall.Finally,thermal performance factor is defined and the effects of wave amplitude on the thermal performance are scrutinized.

Estimate of NO_X production in the lightning channel based on three-dimensional lightning locating system

Based on the VHF lightning locating system,a three-dimensional-space cell-gridded approach is used to extract the lighting channel and calculate the length of the channel.Through clustering of the located radiation sources and then extracting the lightning channel,it can accurately obtain the length of the channel.To validate the feasibility of the approach,a simulation experiment is designed,and it shows the length error is no more than 10%.The relationship between the NO production of per unit arc length and atmospheric pressure obtained in laboratory is applied to the NOX production of per unit flash length at different altitudes in this paper.The channel length and the NOX production of 11 negative cloud-to-ground flashes and 59 intracloud flashes in an isolated thunderstorm in the northeastern Qinghai-Tibet Plateau are calculated.The results show that the average channel lengths of per cloud-to-ground and intracloud flash are 28.9 and 22.3 km respectively;the average NOX productions of per cloud-to-ground and intracloud flash are 1.89×1025 and 0.42×1025 molecules,respectively.

3D Co(II, III) mixed-valence metal-organic framework affording field-induced slow magnetic relaxation

A 3D mixed-valence Co（Ⅲ）-Co（Ⅱ） compound [Co9（bta）10（Hbta）2（H2O）10]n·[22（H2O）]n （1） （H2bta=N,N-bis（1H-tetrazole-5- yl）-amine） was hydrothermally synthesized by reaction of Co（NO3）2·6H2O with H2bta·H2O. Compound 1 consists of three kinds of distorted-octahedral [CoⅡ（N4O2）] paramagnetic nodes which are separated by [CoⅢ（bta）2（Hbta）]2-/[CoⅢ（bta）3]3- dia- magnetic linkers to generate a 3D porous metal-organic framework （MOF） with alternative …Co（Ⅲ）…Co（II）… array and channels incorporating water molecules. Under an applied magnetic field of 4000 Oe, compound 1 exhibits slow relaxation of magnetization at low temperatures, giving AE/kB=30.O0 K and ι0=2.0×10^-8 s.