摘要：Due to their high capacity,the P2-type layered oxide cathodes containing oxygen redox reaction processes have attracted wide attention for sodium-ion ***,these materials usually exhibit poor electro-chemical properties,resulting from irreversible oxygen redox reactions and phase transition processes at high voltages,and thus hinder their large-scale *** work reveals the mechanism for the significantly improved cycle stability and rate performance of Co/Ni-free Na_(0.7)5Li_(0.25-2/3x)CuxMn_(0.75-1/3x)O_(2)via Cu ***-situ XPS demonstrates that Cu doping reduces the amount of Mn^(3+)that triggers the Jahn-Teller effect during the *** addition,the electron enrichment of oxygen around Cu can alleviate the irreversible oxidation of oxygen,and thus suppressing the phase transition originates from the rapid weakening of the electrostatic repulsion between ***,in-situ XRD results verify that the Na_(0.7)5Li_(0.19)Cu_(0.09)Mn_(0.7)2O_(2)maintains the P2 phase structure during charging and discharging,resulting in a near-zero strain characteristic of 1.9%.Therefore,the optimized cathode delivers a high reversible capacity of 194.9 mAh g−1 at 0.1 C and excellent capacity retention of 88.6%after 100 cycles at 5 *** full cell paired with commercial hard carbon anode delivers energy density of 240 Wh kg−*** research provides an idea for designing a new type of intercalated cathode for sodium-ion batteries with low cost and high energy density.

摘要：目的比较5野调强放射治疗(5-field intensity modulated radiotherapy,5F-IMRT)、7野调强放射治疗(7-field intensity modulated radiotherapy,7F-IMRT)和容积旋转调强放射治疗(volumetric modulated arc therapy,VMAT)3种直肠癌术前放疗计划的靶区和危及器官剂量分布。分析各种放疗技术的特点,为临床放疗技术选择提供依据。方法顺序选取北京大学第三医院2016-03-01-2016-05-31收治的10例直肠癌术前放疗患者,分别设计5F-IMRT、7F-IMRT和VMAT计划。比较3组计划靶区和危及器官剂量分布。结果 VMAT的靶区适形性指数(conformity index,CI)优于5F-IMRT和7F-IMRT,7F-IMRT略优于5F-IMRT,CI分别为0.88、0.91和0.92;3种技术HI分别为1.08、1.06和1.08,VMAT比IMRT均匀性稍差,P<0.05。在危及器官剂量中,对于肠道和股骨头,VMAT都增加了低剂量区V_(10)、V_(20),但在中高剂量区V_(30),V_(40)和V_(50)上,受累体积减小;在膀胱剂量中,VMAT技术使得膀胱在低或高剂量受累体积上均低于其他两种技术,7F-IMRT中危及器官剂量介于VMAT和5F-IMRT之间。对于骨髓,VMAT技术30Gy以上体积比较5F-IMRT和7F-IMRT的体积降低,V_(30)(分别为14%、19%和17%)。结论对于直肠癌术前放疗患者,5F-IMRT、7F-IMRT和VMAT均可达到靶区处方剂量要求,靶区的剂量适形性和均匀性都有一定的差异。针对如膀胱、骨髓保护比较重要的患者可以采用VMAT技术减少高剂量的体积以减少放射性损伤,如放射性骨髓抑制;针对如肠道保护比较重要的患者可以选择IMRT技术,减少罹患腹泻等并发症的概率。

摘要：海面物联网在海洋观测、海域监测等应用中发挥着重要作用.复杂动态海洋环境造成海洋网络链路状态、链路质量的时变特征,且其给海面物联网带来了严峻挑战,为此,将物理层自适应数据速率、媒体访问控制(MAC)层载波侦听多址接入与网络层机会路由联合进行跨层设计,提出速率自适应海面物联网跨层传输协议,通过3次握手机制机会性选择最佳转发结点并基于动态信噪比实现传输速率实时自适应调整,旨在提高动态复杂海洋环境下海面物联网的稳健性.陆地和湖上试验结果表明,所提协议在数据包交付率、能耗与时延方面性能优异,可为复杂动态海洋环境中海面物联网数据的高效传输提供重要的技术途径.

摘要：Polyesters,as a class of high-performance and versatile polymer materials,often suffer from some drawbacks,such as hydrophobicity and brittleness due to their single structure ***,modifications have attracted much attention for enhancing their desirable properties,of which one efficient way is incorporating the aliphatic polyether segment into the main chain of the ***,this approach is of much challenge because the obtained polyesters are problematic in either low alternating degree or low molecular ***,we describe an efficient strategy to incorporate polyether fragment into polyester by developing a novel Co-Al based heterodinuclear complex for mediating the copolymerization of propylene oxide(PO)withε-caprolactone(CL).The tracking experiments reveal that PO and CL convert into the polymer chain throughout the polymerization ***,the linear increase in the molecular weight with conversion of CL indicates the controllable nature of the *** competition polymerization,offering the monomer reactivity ratios of rCL=0.96 and rPO=1.04,suggests that the tendency of self-propagation or incorporation of monomers is nearly ***,the obtained polymers with different ether contents exhibit tunable thermal properties with enhanced decomposition temperature for the polymer with higher ether *** newly developed heterodinuclear complex for new polymerization provides an idea to synthesize new functional polymeric materials.

摘要：泡菜在发酵过程中易受微生物污染,柠檬精油、香茅精油和肉豆蔻精油的复配精油有良好的抑菌效果,但精油的配比对其有很大的影响。因此,该研究以正交试验设计考察不同配比的复配精油对泡菜发酵过程中品质的影响,采用CRITIC客观赋权法确定各评价指标的权重系数,结合熵权-TOPSIS综合评价,筛选出最适宜在泡菜中使用的复配精油组合。研究结果表明,复配精油的最佳配比为柠檬精油0.05 g/kg、香茅精油0.15 g/kg、肉豆蔻精油0.15 g/kg。该研究可为泡菜的绿色加工提供参考。

摘要：通过对嘉兴市三塔里小区街道空间利用的调查研究,提出了改善旧居住区内街道尺度失衡状况、改善停车问题、利用废弃空间作为聚集空间等改造设计的对策建议,以期为今后旧居住区内街道空间的设计和改造提供有益参考。

摘要：针对现有仿蝴蝶扑翼飞行器自身重量大、飞行效率较低的问题,设计了一种通过舵机驱动的仿生蝴蝶飞行器。通过精简结构、增大迎面面积等措施,以获得更大的升阻比和平均气动升力,并采用有限元仿真分析对此加以验证。研究结果表明:该飞行器以20°仰角飞行时的平均气动升力最大,能够克服自身重力实现扑翼飞行,基本满足在低空、小扰动环境中的飞行需求。

摘要：光储直流级联系统中光伏与储能级联后接入直流母线,储能系统的加入显著提高了系统全局最大功率跟踪的工作范围。传统低压光伏发电系统通过功率优化器改变端口特性实现全局最大功率点跟踪(MPPT)、提高光伏组件对光能的转换效率,但在功率优化器输出电压范围一定时,系统全局MPPT工作范围较窄。面向于低压光伏发电系统,提出一种光储直流级联系统拓扑设计与控制策略,提高了系统全局最大功率工作范围,实现了储能与光伏的协调控制。实验分析证明了所提系统拓扑与控制策略的有效性。

摘要：基于AMESim仿真平台,结合工程实例(软管恒张力控制系统),以A4VG闭式泵和专用设计的比例恒压控制阀组为基础建立数学模型,对泵的变量控制机构及远程恒压控制调节原理进行仿真分析。在对系统进行仿真和实验的基础上,分析了远程比例溢流阀调定压力和实际工作压力之间的关系和配置不同的阻尼孔对系统调定压力的影响。该系统比泵出口直接加溢流阀调压的方案具有更小的发热量及更好的节能效果,对于该系统在特定工况下的使用起到了一定的启发作用。

摘要：新工科与“双碳”背景下,针对弹药工程与爆炸技术专业教学中面临的学生学习课程数目较多、生师比大、教师承担教学任务较重等现实问题,基于自身科研经历,以“废弃生物质基破岩型燃烧剂”为主线,综合“工程伦理”“推进剂与烟火”“热分析技术”“安全评价”四门专业课程之间的联系,从理念、配方设计、理论性能计算等方面开展了多课程的联动性教学过程设计,实际授课的教学效果良好。多课程的联动性教学方式能够提升学生学习的主动性,提升教师自身的教学能力,为提升专业的教学质量提供教学改革思路。