摘要：Electrochemical reduction from nitrate into ammonia is a chance for nitrate removal from drinking water,while at higher concentrations,this 8-electron reduction process could even become relevant for energy storage,high conversions and low onset potentials ***,we report the synthesis and analysis of a NiFe_(2)O_(4)/C-MS hybrid system made by a molten-salt strategy where the Ni-Fe oxide spinel nanoparticles act as the active center for electrochemical nitrate(NO_(3)−)reduction reaction,while the microporous carbon serves as a conductive support to form a cohesive electrode *** NiFe_(2)O_(4)/C-MS catalyst achieves a maximum NH3 yield rate of 5.4 mg mgcat.^(−1)h^(−1)and Faradaic efficiency of 98%at−0.6 V versus reversible hydrogen *** NiFe_(2)O_(4)nanoparticles buried into microporous carbon,the onset potential decreases *** propose that this reduction originates from charge redistribution in NiFe_(2)O_(4)in the electronic heterojunction with carbon,while enhanced electrolyte diffusion in microporous carbon facilitates high conversion *** functional theory calculations clarify the low energy barrier on NiFe_(2)O_(4),highlighting the essential role of Ni in activating Fe *** COMSOL Multiphysics simulations demonstrate that the microporous curled carbon accelerates NO_(3)−transport and enhances adsorption on the reactive *** work offers insights for designing carbon-based nanocomposites for efficient nitrate reduction electrocatalysis.

摘要：Owing to the excellent redox reversibility and structural diversity,polytriphenylamine(PTPAn)has been regarded as one of the promising cathode candidates for sodium-ion ***,it still suffers from the bulk aggregation and low operating capacity in practical *** by the in-situ polymerization,leaf-like PTPAn nanosheets are uniformly introduced on the surface of carbon nanofibers(CNFs)to form the free-standing CNF@PTPAn composite ***,the formation mechanism of the leaf-on-branch structure of CNF@PTPAn composites is systematically explored,confirming that the controlling of oxidation rate and growth degree plays crucial roles in tuning the morphology and active material content of the composite *** by the capacity-cutting analysis,the effective coupling between the active PTPAn and conductive CNFs can provide fast electron/ion-shuttling channels and deepen the electrochemical reaction *** 50mAg^(-1),the capacity of the optimized CNF@PTPAn composite can reach 105mAh g^(-1),with a stable rate capability of 78mAh g^(-1)even at 400mAg^(-1)after 500 cycles in a half *** detailed kinetic analysis confirms that the ion-storage behaviors in the lowvoltage region can be tailored for the improved capacitive contribution and diffusion ***,the flexible CNF-based full cell with CNF@PTPAn as the cathode and CNFs as the anode exhibits a high energy density of 60Wh kg^(-1)at 938Wkg^(-1).Based on this,the rational design is expected to provide more possibilities to obtain advanced freestanding electrode systems.

摘要：Zinc-ion hybrid supercapacitors(ZHSs)are highly desirable for large-scale energy storage applications owing to the merits of high safety,low cost and ultra-long cycle *** poor rate performance of cathodes,however,severely hinders their ***,aqueous ZHSs with superior performance were fabricated by employing a series of ultrathin carbon nanobelts modified with B,N,O(CPTHBBx).The heteroatom doping can significantly modify the chemical behaviors of carbon frameworks,which could generate numerous active sites and accelerate the charge *** systematic investigation reveals that the B-N groups are active species for fast Zn-ion adsorption and *** a result,the best-performed CPTHB-B2 exhibits an excellent electrochemical performance as cathodes in ZHSs,delivering a high specific capacitance of 415.3 F g^(−1) at 0.5 A g^(−1),a record high capacitance retention of 81%when increasing the current densities from 0.5 to 100 A g^(−1),an outstanding energy density of 131.9 W h kg^(−1) and an exceptionally high power density of 42.1 kW kg^(−1).Our work provides a new cathode design for ultrafast charging Zn-ion storage devices.

摘要：实现碳氮循环是人类社会发展的迫切要求,也是催化领域的热门研究课题。在可再生能源的推动下,电催化技术引起了人们的广泛关注,且可以通过改变反应电压获得不同的目标产品。基于此,电催化技术被认为是缓解当前能源危机和环境问题的有效策略,对实现碳中和具有重要意义。其中,电催化CO_(2)还原反应(CO_(2)RR)和N_(2)还原反应(N_(2)RR)是一种有前途的小分子转化策略。然而,CO_(2)和N_(2)均为线性分子,其中C=O和N≡N键的高解离能导致了它们高的化学惰性。此外,最高占据分子轨道(HOMO)和最低未占分子轨道(LUMO)之间的巨大能量间隙使它们具有高的化学稳定性;且CO_(2)和N_(2)的低质子亲和力使它们难以被直接质子化。另一方面,由于CO_(2)RR和N_(2)RR与析氢反应(HER)具有相近的氧化还原电位,造成其与HER之间存在竞争性关系,这也是致使催化剂在CO_(2)RR和N_(2)RR转化效率低的重要影响因素。因此,CO_(2)RR和N_(2)RR仍然面临着过电位高及法拉第效率低等问题。为了克服这些瓶颈,人们为提升CO_(2)RR和N_(2)RR电催化剂性能做出了很多努力。众所周知,电催化过程发生在催化剂表面,主要涉及质量传递和电子转移等过程。由此可见,催化剂的性能与其质量和电子传输能力密切相关,而调控催化剂表面结构可以优化活性点的质量和电子转移行为。电催化剂的缺陷和界面工程可通过表面原子工程来实现电子结构调控,对于提高气体吸附能力、抑制HER、富集气体及稳定中间产物等具有重要意义。到目前为止,所报道的各种缺陷和复合电催化剂在提高CO_(2)RR和N_(2)RR催化性能等方面均表现出巨大的潜力。在此,我们综述了CO_(2)RR和N_(2)RR中催化剂缺陷工程及界面工程的最新进展;首先讨论了四种不同的缺陷(空位、高指数晶面、晶格应变和晶格无序)对CO_(2)RR和N_(2)RR性能的影响;然后,总结了界面工程在聚合物-无机复合材料催化剂中的重要作用,并给出了典型实例;最后,展望了原子级电催化剂工程的发展前景,提出了开发和设计高效CO_(2)RR和N_(2)RR电催化剂的未来发展方向。

摘要：针对转动支座的结构及工艺要求,选择背面的大平面作为分型面,铸件上的各成形小孔由动静模型芯对接而成;采用偏心侧浇道浇注系统,在金属液的末端均匀开设集渣包及排气槽。用三维软件PRO/E设计模具形状及结构,在二维软件CAD下出图。对该零件的压铸工艺进行了研究,从而提高产品的性能和成品率。

摘要：针对中国航天事业对国产化航天器设计软件的迫切需求,设计了航天器系统仿真软件SpaceSim。面向大规模航天系统仿真效率低,以及多领域先进载荷耦合仿真复杂、传统的时间驱动仿真框架难以满足时敏任务需求等难题,提出了基于GPU的大规模航天系统多领域建模与高效仿真方法,构建了基于时间和事件混合驱动的航天系统软件运行框架,并实现了与第三方软件的高性能联合仿真接口。SpaceSim可完成航天器设计、测试、发射、运控等全任务周期的仿真与验证,可广泛应用于教学科研及型号工程任务。

摘要：针对月球表层土壤的采样任务,设计了一种搭载于机械臂末端的采样器。基于离散元手段,利用Scott真实月壤微型三轴压缩试验数据,完成仿真散体颗粒特性参数匹配,开展了采样器铲取、挖取采样过程的仿真分析,获得作业过程采样器的动力学特性。此外,开发了采样器性能测试系统,针对不同模拟月壤对象进行了采样试验,测试获得了采样器采样能力随深度及月壤硬度的变化情况,得到采样器操作参数的可行区域。采样器能够实现铲取、挖取和封装容器转移多重任务,研究工作为中国未来的月面采样任务提供方案借鉴和技术支撑。

摘要：针对我国1.0 m以下薄煤层开采空间狭小,作业困难,资源丢弃严重及生产能力低,经济效益差等问题,通过理论分析、关键技术开发及现场验证,对制约1.0 m以下薄煤层无人智能化刨煤开采关键工艺技术进行了系统研究;提出了大功率刨煤机与窄矮型液压支架配套的开采技术方案,建立了包含煤层适刨性评价,“单向双切”刨煤工艺、关键设备和智能化控制系统研制以及安全保障措施等内容的1.0 m以下薄煤层综采技术模式;研制了适应煤厚1.0 m以下刨煤机工作面的系列关键装备,包括液压支架采用了大伸缩比立柱、可调节式推移空间、可伸缩式控制阀组、外露式阀锁和管路集成块式联结等新技术,刮板输送机采用嵌入式悬挂布置的轻便式电缆槽和可旋转式机头搭接装置;研究得出了刨深刨速与刨刀消耗量的变化关系,实现了刨深、刨速根据煤层厚度自适应实时调整;研发了综采工作面刨运机组首尾分源供电、同步集成控制技术,降低了采煤工作面供电电缆槽高度,便利了工作面设备、电缆检查和维护,避免推移刮板输送机、拉架对电缆造成伤害和系列电气故障,也降低了工人劳动强度,为实现极薄煤层开采提供了可能。该技术成果在铁煤集团大兴矿N_(1)E902工作面进行了成功应用,实现了智能化无人控制和安全高效生产,为类似条件下极薄煤层无人化开采提供了借鉴。

摘要：间歇性外斜视(IXT)是最常见的斜视类型,手术是其主要的治疗方法。近年随着斜视与小儿眼科领域快速发展,国内多家医疗机构已常规开展IXT手术,但是手术成功率不高,且随着术后时间延长逐渐下降。本文针对临床IXT手术治疗中存在的误区和问题,从准确把握IXT手术的时机、关注IXT手术前的评估、规范IXT手术的设计3个方面进行阐述,以期为临床工作提供指导意见,提高IXT手术的成功率。

摘要：基于离散元方法建立了考虑颗粒间扭转、弯曲力矩及等效引力作用的三维离散元月壤模型,利用三轴仿真试验标定模型细观参数,得到满足真实月壤宏观力学特性的仿真模型。对月壤钻取和整形过程进行了仿真设计,提出了"分层概率法",以每层月壤在运动过程中向邻层错动的概率评价层理保持特性。由仿真结果可知:月壤钻进取样过程中样品层理信息会遭到钻取和整形两次破坏,二者破坏程度相当,且越靠近表层层理信息破坏越严重。分层概率法可有效描述月壤钻取与整形过程月壤样品的层理信息破坏情况,分析结果可为月壤采样机构设计提供参考。