摘要：Near-infrared Ⅱ(NIR-Ⅱ)fluorescent nanoprobes hold great potential for biomedical *** the relationship between surface properties of NIR-Ⅱ nanoprobes and their biological behaviors is particularly important for future probe design and their performance *** the rapid development of NIR-Ⅱ nanoprobes,the distinct role of surface chirality on their biological fates has rarely been ***,chiral NIR-Ⅱ fluorescent Ag_(2)S quantum dots(QDs)are synthesized to investigate the relationship between their chirality and biological functions at both in vitro and in vivo levels.D-/L-Ag_(2)S QDs exhibit significant differences on their interactions with serum proteins,which further affect the cellular *** a result,D-Ag_(2)S QDs can be internalized with higher efficiency(over 2-fold)than that of L-Ag_(2)S ***,in vivo studies reveal that the chirality determines the primary localization of these chiral QDs,where a more efficient renal elimination of D-Ag_(2)S QDs was observed than that of L-Ag_(2)S ***,D-Ag_(2)S QDs show preferential accumulation in tumor region than that of L-Ag_(2)S QDs in orthotopic kidney tumor model,which points out a new avenue of enhancing targeting capabilities of nanoprobes by engineering their surface chirality.

摘要：Learning from nature photosynthesis,the development of efficient artificial catalysts for water oxidation is an ongoing ***,a lamellar cobalt oxide(CoO),black phosphorus(BP)and reduced graphene oxide(RGO)hybrid electrocatalyst is *** domains are anchored on RGO and coated with CoO via P–O *** widespread P–O bond network constitutes the proton acceptor and forms a proton exit channel,akin to the use of Asp61 in Photosystem II(PSII).The innermost kernel layer RGO serves as the current collector and forms an electron exit channel,mimicking the function of Tyr161 for charge *** outermost encapsulation CoO layer acts as water oxidation catalyst(WOC).These biology‐inspired features endow an outstanding OER performance of the hybrid material with a low overpotential of 206 mV at a current density of 10 mA cm^(-2).This work provides a new design guide for OER electrocatalysts through constructing two specialized channels for proton and electron transfer.

摘要：The poor oxygen evolution reaction(OER)activity of two-dimensional(2 D)transition metal carbides(MXenes)is a major obstacle to their application in highperformance water splitting and fuel cells due to the high energy barriers for the absorption of ***,we demonstrate that the lattice oxygen of M_(n)X_(n-1)O_(2)MXenes can be activated by 0 D graphene quantum dots(GQDs),thereby activating the OER via the lattice-oxygen oxidation mechanism(LOM)instead of the conventional adsorbate evolving *** pH-dependent OER activity of M_(n)X_(n-1)O_(2)@GQDs and ^(18)O isotope-labelling experiments with time-of-flight secondary-ion mass spectrometry(TOF-SIMS)provide the direct evidence of ***,the activated lattice oxygen amount can be controlled by the *** as-prepared 0 D/2 D Ti_(3)C_(2)O_(2)@GQDs heterostructure delivers a highly reduced overpotential of 390 mV(bare Ti_(3)C_(2)O_(2):530 mV)at a benchmark current density of 10 mA cm^(-2).Through optimizing the thickness and the additional conductive substrate,the overpotential at 10 mA cm^(-2)decreases to 250 mV,while the Tafel slope is reduced to 39 mV dec^(-1);these values indicate the as-prepared heterostructure is superior to the state-of-the-art MXene-based OER *** work provides a new strategy to enhance the OER activity of M_(n)X_(n-1)O_(2)and extends the application of LOM from perovskite to MXenes.

摘要：The heating load simulation models of the residential buildings in Lhasa are established for enhancing the space organization’s adaptability to climate and radiation and improving its energy saving *** space organization items a e analyzed for both the existing buildings without insulation and new buildings with good *** items include orientation design,south a d north balcony design,the north and south partition wall’s position design,storey height design and window-wall ratio *** results show that orientation is the key design element for energy saving design,and adverse orientation can obviouslyincrease heating energy consumption;south and north balconies can reduce winter heating energy consumption;partition walls move to the north,which means that the south room’s big depth design leads to less heating energy consumption,but the effect is not inconspicuous;smaier storey height results in less heating *** the existing buildings,the window-wall ratio of south side has a balance point for energy saving design in the calculation *** the new buildings with good insulation,enlarging the south window-wal ratio can continuously reduce heating energy consumption,but the energy saving rate between models gets *** heating energy consumption comparison study between the common model and optimal space design model demonstrates that the energy saving design can significantly reduce heating energy consumption

摘要：Design of a giant magnetostrictive ultrasonic transducer for progressive sheet forming was presented.A dynamic analysis of the theoretically designed ultrasonic vibration system was carried out using the finite element method(FEM).In addition,simulations were performed to verify the theoretical ***,a magnetically conductive material was added between the giant magnetostrictive rod and the permanent ***,magnetic field simulations of the transducer were *** influence of the material thickness of the magnetically conductive material on uniformity of the induced magnetic field was ***,the impedance analysis and amplitude measurement were performed to compare the performance of transducers with and without the magnetically conductive *** experimental results show that the magnetic field uniformity is the highest when the magnetically conductive material has a thickness of about 1.6 *** output amplitude of the giant magnetostrictive transducer is improved by adding the magnetically conductive ***,the mechanical quality factor and impedance are reduced,while the transducer operates more stably.

摘要：柔性梁结构是水下航行器的常见部件,其模态振动传递会损害部件服役寿命和系统工作精度。常见的抑制梁振动的方法有吸振、阻尼和主动控制等。控制的难点在于低频抑振和拓宽有效抑制频带。而常见的抑振方法的应用需要获取准确的结构参数和激励参数,对于非完备参数条件系统的适用性不足。本文基于时变边界结构的能量传递特性,提出了一种针对模态振动抑制的时变边界方法。该方法可同时抑制多阶共振,而不必针对每阶振动特性进行额外设计。首先,建立时变边界梁的动力学模型,采用时域分段解析法计算时变边界梁的瞬态振动,并与有限元法的结果进行对比验证了该方法的正确性。然后,通过时变边界梁和固定边界梁的结果对比验证了时变边界方法对共振的抑制效果。最后,分析初始条件、阻尼、时变范围和时变频率等参数对时变边界方法抑振效果的影响,发现阻尼可消耗由模态振动分散至其他频域的能量,时变边界所对应的谐振频率变化范围越大时,对共振峰值的抑振性能越好,并由此得到了时变位置优化区域。

摘要：本文提出了一种考虑几何非线性的三维连续体结构显式拓扑优化方法.采用移动可变形孔洞(MMV)方法描述结构,具有设计变量少、可与CAD系统无缝集成的优点.此外,由于结构拓扑描述模型与有限元分析模型之间解耦,在有限元分析中可以直接删除孔洞区域的冗余自由度,从根本上解决有限变形拓扑优化因弱单元引起的收敛性问题,同时显著提高了有限元分析的计算效率.数值算例验证了该方法的有效性,结果表明:(1)无论单工况还是多工况载荷作用下,几何非线性对三维结构的最优拓扑构型均具有显著影响;(2)优化后的几何非线性结构可以充分利用大位移和小应变来降低结构柔顺度;(3)几何非线性拓扑优化应评估优化设计的临界失稳荷载,以保证结构服役的安全性.

摘要：Constructed by selecting appropriate building blocks,covalent organic frameworks(COFs)can be endowed with a variety of specific ***,we successfully synthesized an imine‐linked H_(2)PReBpy‐COF with the CO_(2) reduction catalyst[ReI(bpy)(CO)_(3)Cl]and the porphyrin photosensitizer as the monomeric building *** light‐harvesting properties of the porphyrin itself,augmented by the extendedπ‐conjugated planar structure of 2D COF,enable H_(2)PReBpy‐COF the excellent light‐harvesting capability,efficient charge separation,and fast interfacial charge *** addition,a large amount of uniformly distributed[ReI(bpy)(CO)_(3)Cl]units offer H_(2)PReBpy‐COF an excellent activity toward photocatalytic CO_(2) reduction with moderate selectivity and *** study demonstrated a proof of concept in which the advantages of COFs and functional monomers are rationally integrated for photocatalytic solar fuel conversion.

摘要：CoFe_(2)O_(4)has been widely used for electromagnetic wave absorption owing to its high Snoek limit,high anisotropy,and suitable saturation magnetization;however,its inherent shortcomings,including low dielectric loss,high density,and magnetic agglomeration,limit its application as an ideal *** study investigated a microstructure regulation strategy to mitigate the inherent disadvantages of pristine CoFe_(2)O_(4)synthesized via a sol–gel auto-combustion method.A series of CoFe_(2)O_(4)foams(S0.5,S1.0,and S1.5,corresponding to foams with citric acid(CA)-to-Fe(NO_(3))_(3)·9H_(2)O molar ratios of 0.5,1.0,and 1.5,respectively)with two-dimensional(2D)curved surfaces were obtained through the adjustment of CA-to-Fe^(3+)ratio,and the electromagnetic parameters were adjusted through morphology *** to the appropriate impedance matching and conductance loss provided by moderate complex permittivity,the effective absorption bandwidth(EAB)of S0.5 was as high as 7.3 GHz,exceeding those of most CoFe_(2)O_(4)-based ***,the EAB of S1.5 reached 5.0 GHz(8.9–13.9 GHz),covering most of the X band,owing to the intense polarization provided by lattice defects and the heterogeneous *** three-dimensional(3D)foam structure circumvented the high density and magnetic agglomeration issues of CoFe_(2)O_(4)nanoparticles,and the good conductivity of 2D curved surfaces could effectively elevate the complex permittivity to ameliorate the dielectric loss of pure CoFe_(2)O_(4).This study provides a novel idea for the theoretical design and practical production of lightweight and broadband pure ferrites.

摘要：二维范德瓦尔斯异质结构广泛应用于光电化学(PEC)型光电探测器、水分解和太阳能电池等光电器件中.其中,Ⅰ型异质结构对于设计新型光电器件至关重要,然而其能带排列对光电响应的影响尚不清楚.本文利用两步物理气相沉积法构建了Ⅰ型SnSe_(2)/ZnS异质结构,并通过紫外光电子能谱和X射线光电子能谱进行了验证.基于Ⅰ型SnSe_(2)/ZnS异质结构的光电化学探测器在紫外可见范围内具有良好的光响应、高稳定性和高灵敏度.SnSe_(2)/ZnS的光响应可达172.60μA W^(-1),分别是单一ZnS和SnSe_(2)样品的7.4和2.0倍.并且,SnSe_(2)/ZnS异质结构具有较高的光电催化分解水活性,在2 h内总产氢量可达81.25μmol ***_(2)/ZnS异质结优异的光电探测和水分解性能主要源于其更高的光利用率和高效电荷传输的协同作用.本工作为通过构建Ⅰ型异质结构来提高光电响应并设计高性能光电探测器和水分解等光电器件提供了一种新方法.