方程式科技

方程式科技专属文献库

已收录 + 条文献

热门标签

{{ item.oftenContent }}

关于公司

{{item.text}}

{{ tab.name }}

何等的灾难!

外文数据库

圣多美和普林西比圣多美德

外文数据库

二维场论中的费米诺零模式

外文数据库

气泡成核势的重建

We calculate analytically the bubble nucleation rate in a model of first order inflation which is able to produce large scale structure. The computation includes the first-order departure from the thin-wall limit, the explicit derivation of the pre-exponential factor, and the gravitational correction. The resulting bubble spectrum is then compared with constraints from the large scale structure and the microwave background. We show that there are models which pass all the constraints and produce bubble-like perturbations of interesting size. Furthermore, we show that it is in principle possible to reconstruct completely the inflationary two-field potential from observations.

外文数据库

基于改进曲线边界生成的无人水面车辆路径规划

外文数据库

在保持铁硼数对称的正则化中违反铁硼数量

外文数据库

自由软件的替代方案:免费软件,开源软件和图书馆

外文数据库

来自南部非洲的两种新型大猩猩(Acari:Macrochelidae)

外文数据库

关于自由教育

外文数据库

在体育教育教师教育中以案例为基础的学习的前期教师观点

外文数据库

威斯敏斯特歌手

外文数据库

爱丽丝·莱蒙德

外文数据库

自动水下车辆轨迹跟踪

This article investigates the practical prescribed-time trajectory tracking control problem for AUVs with parametric uncertainties under tracking error constraints and velocity constraints. A settling time regulator is combined to construct the performance function, with which we build a new adaptive fault-tolerant control scheme upon the transferred error, ensuring that the tracking error converges to an adjustably small residual set within the prescribed time with a continuous control action. Furthermore, with the specific velocity transformation techniques, the problem of velocity constraints is transformed into the boundedness of new variables, thus the feasibility conditions are eliminated, and the requirements of constrained boundary functions are relaxed. Theoretical analysis shows that the proposed control method is an effective way to achieve pre-given tracking precision within the prescribed time, while avoiding the issue of explosion of complexity. The prescribed time is independent of system initial conditions and other parameters, and the tracking error will converge asymptotically. Simulation results further demonstrate the effectiveness of the proposed approach.

外文数据库

罗斯运营:16年经验

外文数据库

金属有机骨架燃烧：具有优异锂离子电池负极性能的 NiO 纳米颗粒的一锅法

NiOnanoparticleswithaverageparticlessizeof30nmaresynthesizedusingaone-potmetal-organicframework-combustion(MOF-C)technique,foruseasananodematerialinrechargeablelithiumionbatteries(LIBs).Thestructuralandelectronicpropertiesofthesenanoparticlesarestudiedusingvarioustechniques,includingpowderX-raydiffraction(PXRD),transmissionelectronmicroscopy(TEM),scanningelectronmicroscopy(SEM),X-rayphotoelectronspectroscopy(XPS),andN2adsorption/desorptionstudies.Theas-synthesizedNiOnanoparticlessustainedreversiblestablecapacitiesof748and410mAh/gatappliedcurrentdensitiesof500and1000mA/g,respectively,after100cycles.Furthermore,theanodedisplaysanotableratecapability,achievingastablecapacityof?200mAh/gatahighcurrentdensityof10A/g.TheseresultsindicatethatthesizeoftheNiOnanoparticlesandtheirhighsurfaceareainfluencetheirelectrochemicalproperties.Specifically,thiscombustionstrategyisclearlyfavorableforimprovingthecyclabilityandratecapabilityofvariousmetaloxidesinrechargeablebatteryelectrodes.

外文数据库

基于TS算法的多异构无人机多任务规划

The model research of multiple task (multi-task) mission planning is useful to improve the combat effectiveness of unmanned aerial vehicle (UAV). Specifically, UAV mission planning is mainly to find a way to optimize resource allocation and to maximize the role of UAV. By combining the characteristics of the task of UAV, analyzing the operational principles and the basic tactical planning flow of UAV, a multi-UAV and multi-task mission planning model with time window is built in this paper. Then, an improved Taboo Search algorithm is proposed for the proposed model. Simulation results demonstrate the feasibility, effectiveness and practical significance of the proposed algorithm for the heterogeneous multi-UAV and multi-task tactical mission planning.

外文数据库

以混合内插线性规划为基础,对无人驾驶航空器进行地雷探测的 " 袖珍 " 阶段最佳地雷探测最佳最佳政策

An optimization problem is formulated to maximize the coverage of the detection area for a fixed wing unmanned aerial vehicle (UAV), which performs a landmine detection mission. The UAV has mine detection devices including magnetic field sensors and chemical sensors. Due to the characteristics of the detection sensors, the UAV should fly at a certain altitude above the ground while following the terrain to perform accurate mine detection. Also, the UAV is required to maintain the pitch angle around the trim value when changing the altitude. Consequently, the altitude change rate of the UAV is limited during the mission. To maximize the mine detection capability within the limit, in this study, the entire flight interval is divided into the intervals on which the mines can be detected accurately and the intervals on which accurate detection is not possible. Logical variables are introduced to indicate the satisfaction of the requirements for accurate detection. Constraints on the logical variables are transformed into a set of linear inequalities containing continuous variables and binary integer variables. Finally, the optimization problem is formulated as a mixed-integer linear programming problem. The effectiveness of the proposed method is demonstrated through numerical simulation.

外文数据库

肛门皮肤标签切除,决定或不决定?

外文数据库

副标题:你无意识的头脑如何规则你的举止。

外文数据库

自然之心 | 联合国教育、科学及文化组织(教科文组织)

外文数据库

职业主义的悖论:重新思考美国军民关系。

外文数据库

使用莱曼α有效不透明的红色移位演化作为暗物质模型的探针

外文数据库

关于一个极大共轭函数的弱型（1,1）不等式

In a celebrated paper, Burkholder, Gundy, and Silverstein used Brownian motion to derive a maximal function characterization of H^p spaces for 0 p infinity. In this paper, we show that their method extends to higher dimensions and yields a dimension-free weak type (1,1) estimate for a conjugate function on the N-dimensional torus.

外文数据库

600细胞的关键非颜色证明贝尔理论

外文数据库

氮掺杂石墨烯和原子层沉积超薄Al2 O3涂层锚定的多孔Fe2 O3纳米棒用于长寿命锂离子电池阳极

Porousironoxide(Fe2O3)nanorodsanchoredonnitrogen-dopedgraphenesheets(NGr)weresynthesizedbyaone-stephydrothermalroute.Afterasimplemicrowavetreatment,theironoxideandgraphenecomposite(NGr-I-M)exhibitsexcellentelectrochemicalperformancesasananodeforlithiumionbattery(LIB).Ahighreversiblecapacityof1016 mAh g−1canbereachedat0.1 A g−1.WhenNGr-I-Melectrodewasfurthercoatedby2ALDcyclesofultrathinAl2O3film,thefirstcycleCoulombicefficiency(CE),rateperformanceandcyclingstabilityofthecoatedelectrodecanbegreatlyimproved.Astablecapacityof508 mAh g−1canbeachievedat2 A g−1for200cycles,andanimpressivecapacityof249 mAh g−1at20 A g−1canbemaintainedwithoutcapacityfadingfor2000cycles.Theexcellentelectrochemicalperformancecanbeattributedtothesynergyofporousironoxidestructures,nitrogen-dopedgrapheneframework,andultrathinAl2O3filmcoating.Theseresultshighlighttheimportanceofarationaldesignofelectrodematerialsimprovingionicandelectrontransports,andpotentialofusingALDultrathincoatingstomitigatecapacityfadingforultrafastandlong-lifebatteryelectrodes.

外文数据库

基于滤波器的干扰观测器和欧拉拉格朗日系统自适应控制及其在四旋翼无人机上的应用

In this paper, a filter-based control scheme is developed for Euler-Lagrange systems with unknown parameter and external disturbance. Two controllers are proposed under the filtering framework, namely the adaptive controller and the disturbance observer-based controller, respectively. A set of low-pass filters are employed in the control design to derive useful filter outputs, which can provide the design freedom for the parameter estimator or the disturbance observer. For the adaptive controller, a certainty equivalent adaptive law is designed in such way that dominates the cross term between the estimation error and the filtered regression matrix to achieve better performance compared with classical estimators. For the disturbance observer-based controller, a high-gain disturbance observer is constructed for the lumped uncertainty with an arbitrary order for users to determine. Experimental results are presented to verify the effectiveness of the proposed schemes on a quadrotor UAV in several cases.

外文数据库

基于基因算法的蒸汽改革器优化策略

外文数据库

由冠状盖泽站点的磁性揭示的循环太阳活动区域喷气机的触发机制

外文数据库

权威途径：无人机地面控制站的智能自适应自动化

Defence Research and Development Canada has conducted a number of human factors analysis tasks and experiments to support the Canadian Armed Force’s acquisition of an unmanned aircraft system for domestic and international operations. Experiments were run on a simulation-based UAS mission experimentation testbed. Results promoted the design and development of an intelligent adaptive interface called Authority Pathway that assists crew members with maintaining situational awareness and to adhere to rules of engagement when targeting. The Authority Pathway uses intelligent adaptive automation technology to adapt to dynamically changing mission goals, provide a variety of views for different users, and allow for varying levels of automation to be consistent with future requirements. Advantages and disadvantages of the Authority Pathway are discussed.

外文数据库

碳纳米管上生长的Sn-C键合锚定SnSe纳米粒子用于高性能锂离子电池阳极

BuildingChemicalbondsisaneffectivestrategytoobtainexcellentperformanceofelectrodematerials.Herein,wereportSnSenanoparticlesgrowthoncarbonnanotubes(SnSe-CNTs)compositewithstrongSnCbondingforhighperformanceLIBsanode.Thecompositeelectrodeexhibitshighreversiblecapacityof772mAhg?1after200?cyclesatacurrentdensityof200?mA?g?1.Evenunderhighercurrentdensityof1Ag?1,thecapacityofcompositeelectrodestillmaintains323mAhg?1after1000?cycles,thecapacityretentionrateisashighas69.5%.ItisfoundthatstrongelectroniccouplingbetweenSnSenanoparticlesandcarbonnanotubesconducivetotherapidtransmissionofelectron/ion,facilitatingthereversibleconversionreactionbetweenSnandLi2SetoformSnSe.Meanwhile,SnCbondingsignificantlyimprovedstructuralstabilityofSnSenanoparticlesgrowthoncarbonnanotubescompositeselectrode.Theseencouragingresultsofchemicalbondingprovidenewopportunitiesfordesigningadvancedelectrodematerials.

外文数据库

硫官能化MXenes在锂离子电池应用中的评价

ThesurfaceterminationofMXenesgreatlydeterminestheelectrochemicalpropertiesandionkineticsontheirsurfaces.Sofar,hydroxyl-,oxygen-,andfluorine-terminatedMXeneshavebeenwidelys...

外文数据库

高z辐射星系周围前景星系的统计过剩

K-band imaging of a sample of 21 radiogalaxies with z \sim 1.5 reveals the existence of a statistical association of foreground galaxies with the positions of the radiosources. The excess is detected within a 1' radius at a high significance level (99.8%). K-band light is a good tracer of stellar mass, so this result indicates the existence of an association between foreground mass perturbations and background radiosources, as expected from the magnification bias effect, and confirms previous results obtained for other high-z radio-loud AGN.

外文数据库

超重/肥胖和西澳大利亚土著和非土著妇女妊娠糖尿病的其他预测因素

外文数据库

安德罗帕斯:目前的概念

外文数据库

英格兰和威尔士的农民(书评)

外文数据库

关于进一步限制进攻性战略武器的基本原则

外文数据库

面向电池退化最小化的多储能插电式混合动力客车能量管理策略

Thepotentialofreducingfuelconsumption,harmfulemissionandcostbenefitforplug-inelectrichybridbusesdependedlargelyonthepowermanagementstrategyforspecifichybridelectricpowertrainconfiguration,especiallyforthosewithcompoundenergystoragesystem.Hybridenergystoragesysteminthisresearchcomprisehighenergylithiumironphosphatebatteriesandsuper-capacitors,therefore,thekeyofimprovingthelifecyclecost-benefitistoextendthecyclelifeforlithiumbattery.Thispaperpresentsanoptimalcontrolstrategyfortheserial-parallelplug-inhybridelectricbusesbasedonthelithiumbatterydegradationmodeltominimizelifecycleoperatingcost.Toderivethegloballyoptimalstrategy,analgorithmbasedontwo-dimensionalPontryagin'sminimumprincipleisproposed.Withtheoptimalstrategy,thebatterydegradationissignificantlyreduced,andthetotalcostisreducedby21.7%comparedwithaplug-inhybridelectricbuswithsingletypeenergystorage.Furtherembodiestheadvantagesofhybridenergystoragesystemsandoptimizationalgorithms.

外文数据库

风车山 - 东方还是西方?

外文数据库

红外图像中刀具的自动检测- IEEE会议出版物

外文数据库

俄罗斯 - 乌克兰冲突对全球粮食安全的影响

外文数据库

在斐波那契 k 号上

外文数据库

微电网应用中基于模糊的锂离子电池充放电控制器

Thisarticlepresentsthefuzzy-basedcharging–dischargingcontroltechniqueoflithium-ionbatterystorageinmicrogridapplication.Consideringavailablepower,loaddemand,andbatterystate-of-charge(SOC),theproposedfuzzy-basedschemeenablesthestoragetochargeordischargewithinthesafeoperatingregion.Variouscontrollingtechniqueshavebeenimplementedtoevaluateandcontrolthebatteryperformance,whichhasthelimitationofcontrollingoverchargingoroverdischarging,complexityincontrol,andlongerchargingtime.Besides,afuzzycontrollerislesscomplexandfaster,asitobviatestheextrasensingcomponents,requiresnoadditionaldeepdischargingandoverchargingprotection,andeasytoimplementduetotheabsenceofmathematicalcalculation.Thenumericalsimulationswiththeloaddemandandthegenerationsdemonstratetheeffectivenessoftheproposedcharging–dischargingcontrollerstrategy.Theefficacyoftheproposedcontrolleristestedundercertainloadvariationsforreal-timeapplication.Theobtainedexperimentalresultshowsthatthedevelopedmodelcancontrolthebatterycharging–dischargingefficiently.Moreover,itisalsoseenfromtheoutputthatthebatterySOCdoesnotgobeyondthelimitoftherespectivesafebatteryoperatingregion(20%–80%).Thus,themaincontributionofthisresearchistodevelopanimprovedfuzzymodeland,thus,implementthesystemforreal-timeapplicationtocontrolthecharging–dischargingofthebattery.

外文数据库

支持矢量机在意大利埃特纳火山震荡分类中的应用

外文数据库

原位X射线吸收光谱实验和第一性原理计算表征锂硫电池初始放电过程中醚基电解质中存在的多硫化物自由基

Thepresenceandroleofpolysulfideradicalsintheelectrochemicalprocessesoflithiumsulfur(Li–S)batteriesiscurrentlybeingdebated.Here,first-principlesinterpretationsofmeasuredX-rayabsorptionspectra(XAS)ofLi–Scellsareleveragedwithanether-basedelectrolyte.Unambiguousevidenceisfoundforsignificantquantitiesofpolysulfideradicalspecies(LiS3,LiS4,andLiS5),includingthetrisulfurradicalanionS3−,presentafterinitialdischargetothefirstdischargeplateau,asevidencedbyalowenergyshoulderintheSK-edgeXASbelow2469eV.ThisfeatureisnotpresentintheXASofcellsatincreaseddepthofdischarge,which,byouranalysis,exhibitincreasingconcentrationsofprogressivelyshorterpolysulfidedianions.Throughacombinationoffirst-principlesmoleculardynamicsandassociatedinterpretationofinsituXASofLi–Scells,atomiclevelinsightsintothechemistriesareprovidedthatunderlietheoperationandstabilityofthesebatteries.

外文数据库

电纺 SnSe/C 纳米纤维作为锂离子和钠离子电池的无粘合剂阳极

Thedesignofelectrodeswithsuperiormechanicalflexibilityisthekeytodevelopingenergystoragedeviceswithmechanicaldurabilityandexcellentelectrochemicalperformance.Herein,aflexibleSnSe/Cnanofibermembraneissuccessfullysynthesizedbyelectrospinningtechnologyandsubsequentcalcination.Fromthemacroscopicview,theSnSe/Cnanofibermembranecantolerateabendingangleof180°withoutanybreakage,indicatingitssuperiormechanicalflexibility.Fromthemicroscopicview,SnSenanoparticlesareuniformlydistributedalongthecarbonnanofiberframework.Thecarbonnanofiberframeworkservesnotonlyasaconductivematrixthatimprovestheelectricalconductivityofthecomposite,butalsoasabuffermaterialthatalleviatesthevolumeexpansionduringelectrochemicalreaction.ThesemeritsendowexcellentelectrochemicalperformancetoSnSe/Cnanofiberswhenusedasabinder-freeandcurrentcollector-freeanodeforlithium/sodiumionbatteries.TheSnSe/Cnanofiberanodedeliversastabledischargecapacityof405mAhg?1at1000?mA?g?1after500cyclesinlithiumionbatteryand290mAhg?1at200?mA?g?1after200cyclesinsodiumionbattery.TheseresultsdemonstratethattheSnSe/Cnanofiberisapromisinganodematerialforflexiblelithium-ionandsodium-ionbatteries."

外文数据库

1984年,美国纽约州立大学法学硕士。 | 拉罗克,自然之光,科学建筑的丹斯·德·哈马因

外文数据库

Lactobacillus Rhamnos 2166的基因组序列草案

外文数据库

废锰锌干电池转化为有效的纳米吸附剂去除有害金属

AnoveltechniquewassuccessfullydevelopedformanufacturingMn-Znferritenano-particlesbyaciddissolutionandferriteprocesses.Thepowdersofwastedrybatteries(PWDBs)wereusedasstartingrawmaterialsbecausetheMnandZncontentinsidethePWDBsispotentiallyhigh.OurdatashowedthatthemostabundantelementsinsidePWDBsaremanganese(41.0%),oxygen(40.6%),zinc(15.3%),andcarbon(3.1%).ItwasfoundthatproperreductantwascriticalfordissolutionwhereFeSO4isessentialforspinelferriteformation.SynthesizedMn-Znferriteparticlesreachedtheirsaturationmagnetizationat63.8 emu/gandweresuccessfullyappliedforAs,Cd,andPbremovalinaqueoussolution.UndertheconditionsofMn-Znferrite0.005 g,volume10 mL,temperature27 °C,andcontacttime1 h,As,Cd,andPbremovalcouldreach99.9,99.7,and99.8%,respectively.WedemonstrateanovelmethodthatcanbeappliedfortransformingWDBsintoresourcematerials.ThisnotonlyreducestheamountofWDBs,butalsosupportstheconceptofwaste-batteryreusablegreen-energypolicy.

外文数据库

还原氧化石墨烯作为包裹在硅/多孔碳纳米纤维上的双功能增强剂，用于高性能锂离子电池阳极

Silicon/porouscarbonnanofiberswrappedbyreducedgrapheneoxide(Si/P-CNFs@rGO)areinnovativelysynthesizedviaaconvenientpreparationprocessconsistingofasimpleelectrospinningmethodfollowedbyacarbonizationprocessandasequentelectrodeposition.Experimentalresultsshowthatsiliconnanoparticles(SiNPs)areanchoredonthecarbonfiberwithrGOtightlywrappedonthefibersurface.ThisrGOprotectivelayeractingasadual-functionalenhancercouldnotonlyaccommodatethevolumeexpansionofSibutalsoenhancetheelectricalconductivity,leadingtoanimprovedelectrochemicalperformance.Theas-obtainedSi/P-CNFs@rGOelectrodeexhibitsanexcellentperformance,withahighreversiblecapacityof1851.3?mAh?g?1atacurrentdensityof0.2?A?g?1withalmostnocapacityfadingupto50thcycle,ahighreversiblecapacityof1217.8?mAh?g?1withanexcellentcoulombicefficiency(CE)of99.0%at0.53?A?g?1after300cycles,andahighdischargespecificcapacityof421.5?mAh?g?1evenatahighcurrentdensityof4?A?g?1.

外文数据库

Schur模的Borel-Weil定理

We present a generalization of the classical Schur modules of $GL(N)$ exhibiting the same interplay among algebra, geometry, and combinatorics. A generalized Young diagram $D$ is an arbitrary finite subset of $\NN \times \NN$. For each $D$, we define the Schur module $S_D$ of $GL(N)$. We introduce a projective variety $\FF_D$ and a line bundle $\LL_D$, and describe the Schur module in terms of sections of $\LL_D$. For diagrams with the ``northeast'' property, $$(i_1,j_1),\ (i_2, j_2) \in D \to (\min(i_1,i_2),\max(j_1,j_2)) \in D ,$$ which includes the skew diagrams, we resolve the singularities of $\FD$ and show analogs of Bott's and Kempf's vanishing theorems. Finally, we apply the Atiyah-Bott Fixed Point Theorem to establish a Weyl-type character formula of the form: $$ {\Char}_{S_D}(x) = \sum_t {x^{\wt(t)} \over \prod_{i,j} (1-x_i x_j^{-1})^{d_{ij}(t)}} \ ,$$ where $t$ runs over certain standard tableaux of $D$. Our results are valid over fields of arbitrary characteristic.

外文数据库

点击上传

只能上传jpg/png文件，且不超过500kb