方程式科技

方程式文档文献分享平台

会员

我的主页

个人中心

退出登录

登录网站，可立即获得以下权益：

 收藏有用内容

 阅读优质知识

 进行评论互动

 分享有用知识

立即登录

已收录 + 条文献

热门标签

{{ item.oftenContent }}

关于公司

{{ tab.name }}

进出口正对型腔体冷却板对锂离子电池的散热效果

Duetoitshighthermalsensitivity,apowerlithium-ionbatteryforvehiclesrequiresanefficientcoolingsystemtoensuresafetyandgoodperformance.Excellentheatdissipationcapacityenablestheliquidcoldplatecoolingsystemtohavebetterapplicationprospects.However,allexistingcoldplatesimprovetheircoolingcapacitybyincreasingthecomplexityoftheirstructure.Therefore,directlyoppositeinletandoutletcavitycoldplatecoolingsystemswithsimplestructuresareestablished.Twokindsofcavitycoldplates(ModelIandModelL)withdifferentinletandoutletpositionsareanalyzedusingthenumericalsimulationmethod.Theeffectsofinletandoutletsizes,coolantmassflowrate(qm),andinletandoutletpositionsonthetemperaturefieldaswellasthecoldplatepressuredroparestudied.Accordingtotheresults,maximumtemperaturesofbatteriesappearatfourcornersofcavitycoldplates,whicharelowerthan35?°C.ThecoolingcapacityandtemperatureuniformityofModelIcoolingsystemsarebetterthanthoseofModelL.However,theheatdissipationcapacityofModelLismoresensitivetoqmthanthatofModelI.PressuredropofModelLissmaller.Thismethodmeetstheheatdissipationofvehiclepouchlithium-ionbatteries.

无线传感器网络中的数据收集

SnO 2 @MWCNT 纳米复合材料作为钠离子电池的高容量负极材料

WereportthesynthesisandcharacterizationofSnO2@multiwalledcarbonnanotubes(MWCNTs)nanocompositeasahighcapacityanodematerialforsodium-ionbattery.SnO2@MWCNTnanocompositewassynthesizedbyasolvothermalmethod.SEMandTEManalysesshowtheuniformdistributionofSnO2nanoparticlesoncarbonnanotubes.WhenappliedasanodematerialsinNa-ionbatteries,SnO2@MWCNTnanocompositeexhibitedahighsodiumstoragecapacityof839 mAh g?#xA0;1inthefirstcycle.SnO2@MWCNTnanocompositealsodemonstratedmuchbettercyclingperformancethanthatofbareSnO2nanoparticlesandbareMWCNTs.Furthermore,thenanocompositeelectrodealsoshowedagoodcyclabilityandanenhancedCoulombicefficiencyoncycling.

频率和荧光灯

为什么摩擦焊接已经获得认可

用于无人机自动着陆的稳健的基于视觉的跑道检测和跟踪算法

This work presents a novel real-time algorithm for runway detection and tracking applied to the automatic takeoff and landing of Unmanned Aerial Vehicles (UAVs). The algorithm is based on a combination of segmentation based region competition and the minimization of a specific energy function to detect and identify the runway edges from streaming video data. The resulting video-based runway position estimates are updated using a Kalman Filter (KF), which can integrate other sensory information such as position and attitude angle estimates to allow a more robust tracking of the runway under turbulence. We illustrate the performance of the proposed lane detection and tracking scheme on various experimental UAV flights conducted by the Saudi Aerospace Research Center (KACST). Results show an accurate tracking of the runway edges during the landing phase, under various lighting conditions, and suggest that such positional estimates would greatly improve the positional accuracy of the UAV during takeoff and landing phases. The robustness of the proposed algorithm is further validated using Hardware in the Loop (HIL) simulations with diverse takeoff and landing videos generated using a commercial flight simulator.

用于高性能双离子有机对称电池的具有双极和双氧化还原活性中心的共轭微孔聚合物

Redox-activeconjugatedmicroporouspolymers(RCMPs)havereceivedremarkableinterestinelectrochemicalenergy-storagesystemsinviewoftheirporousstructureandtunableredoxnature.ThisworkpresentsaneffectivestrategytoconstructRCMPswithbipolaranddoubleredox-activecentersbyintegratingcopper(II)tetraaminephthalocyanine(CuTAPc)and1,4,5,8-naphthalenetetracarboxylicdianhydride(NTCDA)unitsintotheRCMPs(CuPcNA-CMP).Asexpected,CuPcNA-CMPhaspotentialapplicationinthehalfcellsofdual-ionbatteries(lithiumbasedDIBs,LDIBs),asymmetricDIBs(graphitebasedDIBs,ADIBs),andsymmetricDIBs(allorganicDIBs,SDIBs).Amongthem,LDIBsshowahighreversiblecapacity(202.4mAhg?1at0.2Ag?1)andexcellentratecapability(86.1mAhg?1at5Ag?1).AndADIBsalsoshowahighreversiblecapacity(245.3mAhg?1at0.1Ag?1),longcyclestabilitywithcapacityretentionof89%after500cycles,andgoodrateperformance(125.1mAhg?1at5Ag?1).Inaddition,SDIBsshowhighinitialcharge/dischargecapacitiesof269.4/198.5mAhg?1at0.05Ag?1andahighcellvoltageof2.5V.Meanwhile,themechanismofCuPcNA-CMPonhostingbothanions(PF6?)andcations(Li+)isinvestigatedbydetailedexperimentalanalysisanddensityfunctionaltheorystudies.

菲律宾人的身体形象

X 空间中的超对称正则化路径集成测量

用于计算 NMR 屏蔽和间接自旋耦合常数的 Ab Initio 方法

关于Selberg积分一个主题的变分

In this paper we calculate some Generalized Selberg integrals. The answer is expressed in terms of $\Gamma$-functions. Integrals of this type serve as normalization constants or directly via undoing 2-D integrals for determination of structural constants of operator algebra.

新型5 V级锂离子电池正极材料Li 2/3 Ni 1/3 Mn 2/3 O 2 的合成及电化学性能

•O3-Li2/3Ni1/3Mn2/3O2issynthesizedbythermaltreatmentat500°C.•TheinitialdischargecapacityofLi2/3Ni1/3Mn2/3O2withthermaltreatmentat500°Cis257mAhg−1.•Thecharge/dischargeprofilesshowanovelhigh-potentialplateauregionat4.8V.

面部美容手术的争议

社会学与经济学 | 前瞻性

基于集群的MAC协议,用于在水下无线传感器网络中避免碰撞和TDMA调度

通过卫星和空天一体化网络中的速率分割多址接入支持物联网

To satisfy the explosive access demands of Internet-of-Things (IoT) devices, various kinds of multiple access techniques have received much attention. In this article, we investigate the multicast communication of a satellite and aerial-integrated network (SAIN) with rate-splitting multiple access (RSMA), where both satellite and unmanned aerial vehicle (UAV) components are controlled by network management center and operate in the same frequency band. Considering a content delivery scenario, the UAV subnetwork adopts the RSMA to support massive access of IoT devices (IoTDs) and achieve desired performances of interference suppression, spectral efficiency, and hardware complexity. We first formulate an optimization problem to maximize the sum rate of the considered system subject to the signal-interference-plus-noise-ratio requirements of IoTDs and per-antenna power constraints at the UAV and satellite. To solve this nonconvex optimization problem, we exploit the sequential convex approximation and the first-order Taylor expansion to convert the original optimization problem into a solvable one with the rank-one constraint, and then propose an iterative penalty function-based algorithm to solve it. Finally, simulation results verify that the proposed method can effectively suppress the mutual interference and improve the system sum rate compared to the benchmark schemes.

最大限度地提高电力储存的价值

Wedemonstrateasimplealgorithmforstorageprovidingarbitrageandreserve.Thiscalculatesthetimeprofileofstoragedispatchtogiveoptimalprofits.Ouralgorithm’scodeismadeavailableopensourcetothecommunity.Batteryelectricitystorageiscurrentlyuneconomicalwhenjustshiftingenergy.ProvidingreservecantripletherevenueforstorageintheBritishelectricitymarket.

考虑不确定因素的尾散尾无人驾驶飞行器强劲过渡轨轨迹优化

In this study, the robust transition trajectory optimization was conducted for tail-sitter UAVs. The correlated stochastic uncertainties are different from existing deterministic optimal transition studies and are considered for the first time. Simulation results show that the robustness of the derived transition trajectories is improved. In the future, we will study more complicated unknown uncertainties. In addition, the robust control law for the tail-sitter transition phases will also be studied.

对Li4Ti5O12作为锂离子电池阳极材料的兴奋剂策略进行审查

热解-酸洗法制备氧化铅/炭黑复合材料及其对铅酸蓄电池高速部分充电性能的影响

Newpyrolysis-picklingmethodwasdevelopedtomakePbO/carbonblack(CB)additive.Pyrolysis-picklingprocessingincreasesalkalinesurfacegroupsonCB.PbO/CBcompositescaneffectivelyinhibittheH2evolutioninnegativeplates.PbO/CBcompositeswithlowerPbOcontentincreaseHRPSoCcyclelifesignificantly.

使用凯恩方法的水下蛇形机器人的动态模型

“美国”

2013年《高级护理杂志》的扩展

基于单目视觉的小障碍物深度估计

In order to solve the problem of small obstacles avoidance in ultra-low altitude flying of unmanned aerial vehicles (UAVs), a depth estimation algorithm based on monocular visual for small tower obstacles is proposed by combining deep learning and traditional methods. With the advantage of convolutional neural networks to extract the salient features of the images, a lightweight and multi-level residual convolution neural network for obstacle segmentation is proposed. The cross-entropy loss function is optimized by adding the weight of the background and obstacles area. A method based on pairs of coplanar points is introduced to complete the depth estimation of a single frame image. Moreover, the recursive formula of sequence images depth results is derived, and a multi-frame voting optimization algorithm is proposed. Finally, the simulation results show that the proposed algorithm can effectively realize the fast segmentation and accurate depth estimation of the small tower obstacles in the sequence images.

基于学习的鲁棒安全传输可重构智能表面辅助毫米波无人机通信

In this letter, we study the robust and secure transmission in the millimeter-wave (mmWave) unmanned aerial vehicle (UAV) communication assisted by a reconfigurable intelligent surface (RIS) under imperfect channel state information (CSI). Specifically, the active beamforming of the UAV, the coefficients of the RIS elements and the UAV trajectory are jointly designed to maximize the sum secrecy rate of all legitimate users in the presence of multiple eavesdroppers. However, the CSI is coupled with the UAV trajectory, which results in complex constraints. Furthermore, the time-related issue caused by the outdated CSI also makes the formulated problem intractable to solve. To tackle these challenges, by leveraging the deep deterministic policy gradient (DDPG) framework, a novel and effective twin-DDPG deep reinforcement learning (TDDRL) algorithm is proposed. Simulation results demonstrate the effectiveness and robustness of the proposed algorithm, and the RIS can significantly improve the sum secrecy rate.

时域频率估计在无人机桨叶损伤故障诊断中的应用

In this paper, a novel time-domain frequency estimation approach is proposed based on the well-known Subspace Identification Method (SIM). Differing from the Fast Fourier Transformation (FFT) method, the nonlinear identification for frequency estimation is reformulated into the eigenvalue identification problem, which avoids the spectrum peak search. The recursive frequency estimation approach is proposed based on the updating/downdating of the Cholesky decomposition, where the extended observability matrix can be identified from a small matrix with lower computation cost. In addition, a gap metric-oriented performance indicator is proposed as a test statistic for fault detection as well as the evaluation of fault severity. The effectiveness of the proposed methods is verified for frequency estimation and fault diagnosis performance through numerical simulations and the experimental measurements from a laboratory unmanned aerial vehicle (UAV) rig with partial blade damage.

剑桥圣经大会

博物馆网站的可用性评估

L 1 为坚固的轨迹跟踪提供后退步 *

杰夫·谢尔(1935年-8211年)

进行有效的泰尔盖特训练

基于螺旋线的空中骨干网逼真3D群体移动模型

For search and rescue (SAR), the group unmanned aerial vehicle (GUAV) can rapidly cover the disaster area, and it can provide reliable connectivity to victim by aerial backbone network (ABN). However, existing 3D aerial mobility model (3D AMM) cannot capture unique features of GUAV in SAR, especially smooth 3D trajectory and collision avoidance. In this paper, we develop realistic 3D aerial group mobility model based on spiral line (3D SLGM) for SAR. Firstly, we review some related works. Then, we introduce the mechanism of 3D SLGM, such as Z-Or-SLGM and Z-Non-SLGM. Furthermore, we analyze some mathematical features of 3D SLGM. In addition, we investigate key mobility features of 3D SLGM. Finally, we evaluate the network performance under 3D SLGM. The result shows that 3D SLGM has smooth 3D trajectory and uniform distribution of spatial nodes in 3D space. With the collided rate of 0%, 3D SLGM merely takes about 1.4 minutes to cover 100% of the target area of 200 m*200 m. Besides, the network under 3D SLGM can approach the throughput of 0.45 Mb/s, the end-to-end delay of 3.2 ms and the loss packets rate of 0%. We believe that 3D SLGM, as a significant supplement of 3D AMM, can provide many helpful guidelines in the design and analysis of authentic ABN.

适用于高效率应用的射频功率放大器设计

In this paper a time domain waveform measurement system with active harmonic load-pull has been used to enhance the design cycle of RF power amplifiers (PAs). Wave-shaping (waveform engineering) techniques using Cardiff University's high power waveform measurement system have yielded optimum device conditions enabling a rapid PA realisation with a first-pass success. The resulting inverse class-F design, based on a 10W GaN HEMT device, is operating at 0.9GHz, and achieving 81.5 % drain efficiency in both the load-pull emulated state and also in the directly realised PA. The value of measured waveforms, and the ability to engineer optimum waveforms to a specific amplifier mode, is demonstrated in this study. % drain efficiency in both the load-pull emulated state and also in the directly realised PA. The value of measured waveforms, and the ability to engineer optimum waveforms to a specific amplifier mode, is demonstrated in this study.""""""

服务前小学教师的空气污染概念分析

太阳能光伏应用的并行功率处理拓扑

nefficientconvertertopologyforextractingmaximumpowerfromaphotovoltaicmoduleispresentedinthispaper.Theproposedtopologyisimplementedonastand-alonebatterychargingsystem.Areversedbuck-boostconverterenablingparallelpowerprocessing(PPP)withapowerswitchreferencedtothecommonreturnisthecoreofthechargingsystem.Small-signalanalysisoftheproposedchargingsystemiscarriedouttofacilitatethedesignofacompensatorformaximumpowerpoint(MPP)tracking.ThesimulationandexperimentalresultsconfirmthevalidityofthemodelandverifythehighefficientoperationwhiletrackingtheMPP.TheuseofthePPPwithsplitloadsisalsopresentedwhichwouldimprovetheconvertersize,efficiency,andstep-downdutyratio.

阻尼环境中的气泡碰撞与缺陷形成

Within the context of a first-order phase transition in the early Universe, we study the collision process for vacuum bubbles expanding in a plasma. The effects of the plasma are simulated by introducing a damping term in the equations of motion for a $U(1)$ global field. We find that Lorentz-contracted spherically symmetric domain walls adequately describe the overdamped motion of the bubbles in the thin wall approximation, and study the process of collision and phase equilibration both numerically and analytically. With an analytical model for the phase propagation in 1+1 dimensions, we prove that the phase waves generated in the bubble merging are reflected by the walls of the true vacuum cavity, giving rise to a long-lived oscillating state that delays the phase equilibration. The existence of such a state in the 3+1 dimensional model is then confirmed by numerical simulations, and the consequences for the formation of vortices in three-bubble collisions are considered.

为办公楼提供空调的太阳能驱动喷射式制冷系统模型

水力动力学湍流理论

α-Fe2O3/SnO2异质结构复合材料：一种用于锂离子电池的高稳定性阳极

α-Fe2O3microovalstructuredecoratedwithSnO2nanocrystalsarefabricatedbyhydro-thermalprocess.Thecompositeheterostructurehasauniformsizeof310?nminlengthand110?nminwidth,andSnO2shellthicknessis?10?nm.TheSnO2shellactsasaconductivelayertoofferfastpathwaysfortransportofelectronsandions.Whatismore,theSnO2layerservesasaninactivematrixforα-Fe2O3particles,avoidingagglomerationandkeepingstructuralintegrity.Benefitingfromthesmartdesign,thehierarchicalα-Fe2O3/SnO2compositeasanodeexhibitsahigherspecificcapacityandabetterrateperformancethanthoseofpristineα-Fe2O3structures.Thestabilityelectrochemicalperformanceofthehierarchicalcompositecanbeputdowntothecore-shellarchitecture,whichimprovestheconductivityandstabilityoftheelectrodes.Theheterostructuredesigninourworkprovidesapossibleapproachtosynthesishighstabilitymaterialsforelectrochemicalenergystorage.

H-Infnitiy 用于世界原油价格估算

层结构过渡金属二硫族化合物结晶度对钾离子电池性能的影响——以二硫化钼为例

Layer‐structuredtransitionmetaldichalcogenides(LS‐TMDs)arebeingheavilystudiedinK‐ionbatteries(KIBs)owingtotheirstructuraluniquenessandinterestingelectrochemicalmechanisms.Syntheticmethodsaredesignedprimarilyfocusingonhighcapacities.Theachievedperformanceisoftenthecollectiveresultsofseveralcontributingfactors.Itisimportanttodecouplethefactorsandunderstandtheirfunctionsindividually.Thisworkpresentsastudyfocusingonanindividualfactor,crystallinity,bytakingMoS2asademonstrator.Theperformanceoflowandhigh‐crystallizedMoS2iscomparedtoshowthefunctionofcrystallinityisdependentontheelectrochemicalmechanism.Lowercrystallinitycanalleviatediffusionallimitationin0.5–3.0V,whereintercalationreactiontakeschargeinstoringK‐ions.HighercrystallinitycanensurethestructuralstabilityoftheMoS2layersandpromotesurfacechargestoragein0.01–3.0V,whereconversionreactionmainlycontributes.Thelow‐crystallizedMoS2exhibitsanintercalationcapacity(118mAhg?1),goodcyclability(85%over100cycles),andgreatratecapability(41mAhg?1at2Ag?1),andthehigh‐crystallizedMoS2deliversahighcapacityof330mAhg?1at1Ag?1andretains161mAhg?1at20Ag?1,beingoneofthebestamongthereportedLS‐TMDsinKIBs.

迈向阿凡达无人机：用于空中操纵的人体无人机

This paper presents Avatar-Drone to advance aerial manipulation. The mobile-manipulating drone is a haptics-based human-in-the-loop platform. This is married to an immersive framework based on Unity and virtual (VR) and augmented (AR) reality. The net effect provides the operator a sense of presence and see, hear, and feel what the drone is doing in the work environment. Two scenarios involving package delivery illustrate efficacy of this marriage.

无人机机翼变形导致的气动弹性行为

为提高 LiFePO4 电池的电化学性能,对电极杂质制备进行全面努力

阅读流畅在儿童文本理解中的作用

在动态杂乱环境中由传感器网络导航的轮式移动机器人全球最短路径规划

一种多AUV合作导航方法

Cooperative navigation is one of the key methods for multiple autonomous underwater vehicles (AUVs) to obtain accurate positions when performing tasks underwater. In the realistic state-space model of the multi-AUV cooperative navigation system, where the system noise does not satisfy the additivity, it is necessary to augment the dimension of the state variables before nonlinear filtering. Aiming at the problem that the error of traditional algorithms increases linearly with the dimension of state-space, a cooperative navigation method based on Augmented Embedded Cubature Kalman filter (AECKF) algorithm is proposed. The experiment results show that the AECKF cooperative navigation algorithm has better positioning accuracy and stability than the traditional algorithm.

Dilute Interacting Bose 气体的过渡温度

英语加:双语教育的问题 | [无标题]

北安许可证申请程序。

点击上传

只能上传jpg/png文件，且不超过500kb