摘要：为避免碟式太阳能热发电系统风激共振破坏问题,采用流体控制方程建立碟式太阳能热发电系统流场模型,并将计算得到的碟式太阳能热发电系统流场流速和压力再加载到聚光器前后表面,对碟式太阳能热发电系统流固耦合模态进行分析研究。研究结果表明:流固耦合场对碟式太阳能热发电系统模态振型的影响较小,而对碟式太阳能热发电系统的固有频率和最大变形量的影响较大,但其影响程度随模态阶数的递增而递减;与高度角β=0°时碟式太阳能热发电系统固有频率相比,高度角β=45°时碟式太阳能热发电系统固有频率均不同程度地减小,但最大变形量基本上保持不变;碟式太阳能热发电系统聚光器的上边缘以及4个悬臂梁靠近电机的部分最容易受到损坏,故应提高此部位的刚度。

摘要：Non-hermiticity presents a vast newly opened territory that harbors new physics and applications such as lasing and ***,only non-Hermitian systems with real eigenenergies are stable,and great efforts have been devoted in designing them through enforcing parity-time(PT)*** this work,we exploit a lesser-known dynamical mechanism for enforcing real-spectra,and develop a comprehensive and versatile approach for designing new classes of parent Hamiltonians with real *** design approach is based on a new electrostatics analogy for modifed non-Hermitian bulk-boundary correspondence,where electrostatic charge corresponds to density of states and electric felds correspond to complex spectral *** such,Hamiltonians of any desired spectra and state localization profle can be reverse-engineered,particularly those without any guiding symmetry *** recasting the diagonalization of non-Hermitian Hamiltonians as a Poisson boundary value problem,our electrostatics analogy also transcends the gain/loss-induced compounding of foating-point errors in traditional numerical methods,thereby allowing access to far larger system sizes.

摘要：Heteroatom-doped Pt-based nanocrystals have generated considerable interest and hold great prospects in heterocatalysis. However, engineering the superficial atomic configurations of these nanocrystals via in situ surface doping remains exceedingly challenging. Herein, we propose a onepot, in situ surface doping chemical synthesis protocol to prepare quatermetallic Pt Ni Co Rh dendritic nanocrystals as versatile and active catalysts for the electrooxidation of C_(1) fuels. Leveraging the selective coordination effect between ascorbic acid and Rh^(3+)ions, the doping of trace Rh atoms can be guided specifically at the near-surface of Pt Ni Co Rh nanocatalysts. Electrocatalytic tests indicate that Pt_(67)Ni_(16)Co_(16)Rh_(1) nanocrystals with in situ trace Rh-doped surface exhibit substantially enhanced activity, durability, and CO tolerance for the electrooxidation of methanol, formaldehyde, and formic acid. In situ Fourier transform infrared spectroscopy provides molecular-level insight into the exceptional performance of these nanocatalysts. The surface incorporation of anticorrosive Rh atoms enables the transfer of CO intermediates from the atop Pt sites to the bridged Rh–Pt surface sites,thereby facilitating the elimination of these poisoning species from the catalyst surface. This study presents an effective in situ surface doping strategy which can enable the design of more atom-economic heterocatalysts.

摘要：The present study reports investigations on rheological,mechanical,thermal,tribological and morphological properties of feedstock filaments prepared with polylactic acid-polyether ketone ketone-hydroxyapatite-chitosan(PLA-PEKK-HAp-CS)composite for 3D printing of functional *** study consists of a series of melt processing operations on melt flow index(MFI)setup as per ASTM D-1238 for melt flow certainty followed by fixation of reinforcement composition/proportion as 94%PEKK-4%HAp-2%CS(B)by mass in PLA matrix(A).The blending of reinforcement and preparation of feedstock filament for fused deposition modeling(FDM)set up has been performed on commercial twin screw extruder(TSE).The results of study suggest that feedstock filaments prepared with blend of 95%A-5%B(by mass)at 200℃processing temperature and 100 r/min rotational speed on TSE resulted into better tensile properties(35.9 MPa peak strength and 32.3 MPa break strength)with 6.24%surface porosity,42.67 nm surface roughness(R_(a))and acceptable heat capacity(2.14 J/g).However as regards to tribological behavior,the minimum wear of 316μm was observed for sample with poor tensile *** regards to crash application for scaffolds the maximum toughness of 1.16 MPa was observed for 85%A-15%B(by mass)at 200℃processing temperature and 150 r/min rotational speed on TSE.

摘要：Cocrystal has been discovered and studied for more than 170 years since 1844, while the applications to optoelectronics only begin in the last decade. Several general questions that chemists and materials scientists currently seek to answer are: can we design and control the molecular self-assembly and cocrystal growth, what’s the packing-property correlations, as well as how can we improve device parameters for real applications in industry. In this contribution, we review our and other groups’ recent advances in the cocrystal research field sequentially including:(1) nucleation and growth mechanisms for selective preparation of cocrystals with different donor/acceptor ratio and morphology;(2) charge transport and electronic devices, particularly field-effect transistor(FET) and photo-response device. We discuss the in-situ single crystal device fabrication method, ambipolar charge transport, and molecular packingcharge separation correlation;(3) photonic and optical property, focusing on optical waveguide, photonic logic computation, and nonlinear optics(NLO). We present unusual optical properties revealed by advanced instruments and general structure-function relations for future study. Importantly, the extensive investigations described herein yield in-depth and detailed understandings of molecular cocrystals,and show that such bi-component material systems together with the developed instrument measurement methodologies have the potential to initiate unconventional electronic and photonic science and technology.

摘要：在现代工业设计、人工智能、软件设计等领域,三维模型正展现强劲需求与活力,传统三维模型特征提取方法仅能提取模型表面特征,难以满足复杂模型特征提取需求,为提高三维模型的特征提取精度,基于光谱分析以及可见光传播特性,提出一种具有高区分度的三维模型特征提取方法。首先利用光散射系数、吸收系数、各向异性等光学特性参数,量化分析光在不同介质中透射、散射、反射概率,并确定最佳光谱模拟波段;其次采用Monte-Carlo法模拟光子束在三维模型中的传播历程,获得光子束传播轨迹的角度、距离、能量等多种统计量,计算不同统计量权重,经过统计分析后完成特征提取;然后在ESB国际通用三维模型库中,测试不同光子束数量、约束空间形状对特征提取效果影响,从而确定最佳模拟参数;最后使用多种特征提取方法与光传播模拟法进行特征提取效果比较,并采用查准率、查全率以及E测度评价指标对特征提取效果进行定量测试。实验结果表明,三维模型特征提取准确度对光传播约束空间形态较为敏感,光子传播的最佳约束空间为球体;三维特征提取效率随着光子束数量升高而降低,在保证特征提取精度的前提下,10000~25000区间是光子束模拟数量的最佳取值范围;基于光传播模拟的特征提取准确度高于小波变换、距离夹角以及D2分布方法,能够满足三维模型检索需求,更适合复杂三维模型的离线特征提取与应用。结合光谱分析与可见光传播特性的模型特征提取法拓宽了光谱分析的应用范围,能够提取出融合三维模型表面特性与内部形态的有效特征,为高精度特征提取技术研究注入新动力。

摘要：Transformation of lignin into high-value chemicals is hampered by the complexity of monomers obtained from lignin depolymerization. Here we report a strategy, composed of hy-dro-demethoxylation and de-alkylation reactions, that is able to chemically converge various lig-nin-derived phenolic monomers into phenol in a single-step. Using 2-methoxy-4-propylphenol as a model compound, Pt/C exhibited the best performance in hydro-demethoxylation reaction afford-ing 80% 4-propylphenol from 2-methoxy-4-propylphenol, while H-ZSM-5 was identified as the most suitable catalyst for de-alkylation, achieving 83% yield of phenol from 4-propylphenol. Since the two catalysts operate under compatible conditions, combining the two catalysts to simultane-ously promote both hydro-demethoxylation and de-alkylation reactions was achieved. Configura-tion of how to organize the catalysts is a critical parameter, where the physical mixture of the two was most effective, providing over 60% phenol from 2-methoxy-4-propylphenol in a single-step.

摘要：目的旨在调查泰国护理专业本科学生循证实践(evidence-based practice,EBP)水平的现状。方法采用横断面研究设计。于2021年1一3月选取泰国5所公立大学的470名三年级和四年级的护理本科学生进行调查。采用学生循证实践问卷(the Student Evidence-Based Practice Questiomnaire,S-EBPQ)进行调查。结果S-EBPQ总均分为(5.29+0.71)分,4个分量表均分从高到低分别为态度(5.50+0.93)分、分享和应用EBP(5.37±0.87)分、实践(5.18+0.84)分、检索和回顾证据(5.10+0.81)分。有较多的EBP学习经历、熟悉研究方法、对临床决策有信心、对实践有准备及通过查阅期刊获取实践证据的护理专业学生EBP水平较高(P<0.05)。结论本研究可以为提高护理专业本科生在临床环境中的EBP水平提供策略,并可以应用到现有的护理课程中。

摘要：本文研究了带有未知的时序趋势的序贯试验概率罐子模型，对于时序趋势构造了一种估计量，从而建立了一种广义的Ｆｒｉｅｄｍａｎ概率带子模型，并且在这种序贯试验模型下获得了强相合性、渐近正态性等极限定理，这些结果为临床试验设计的应用提供了一定的理论根据．

摘要：这份报纸为反复的学习控制(ILC ) 论述一种新反馈前馈控制配置与反馈设计，它由反馈和一个前馈控制部件组成。反馈积分控制器稳定系统，并且在操作，和前馈控制 ILC 期间起主导的作用补偿可重复的非线性 / 未知的变化时间的动力学和骚乱，从而提高性能独自由反馈控制完成了。作为这控制策略的最有利的点，没有作努力到前馈控制 / 反馈获得的 reconfigurate 或重新调律，前馈控制 ILC 和反馈控制能独立地或联合工作。与严密分析，建议学习控制计划沿着重复轴保证 asymptotic 得到集中。