二维有机-无机杂化钙钛矿非线性光学研究进展(特邀)

自从钙钛矿材料问世以来,有机-无机杂化钙钛矿材料在近数十年的时间得到了蓬勃发展。二维(2D)有机-无机杂化钙钛矿是由典型的无机八面体框架以及不同的有机阳离子构成,其具有本征的量子阱结构和有趣的光电特性,也因此在发光、传感器、调谐、光伏体系以及通讯设备等领域引起了人们的密切关注。低成本、可溶液法制备、以及可替换的有机阳离子等特性使二维杂化钙钛矿在光学和光子应用中具有灵活的层间距,层数和可变的晶格扭曲,从而实现可调节的框架以及在光学和光子学应用中的高调节度。尤其地,它们也表现出突出的二阶、三阶和高阶非线性光学特性,例如在激光脉冲激发下的二次谐波产生(SHG)、太赫兹、双光子吸收(2PA)和饱和吸收(SA)和三光子吸收(3PA)等。讨论了具有不同结构特点的二维杂化钙钛矿的构建,并重点介绍了这些二维杂化钙钛矿在线性和非线性光学领域地特性和应用。最后,对二维杂化钙钛矿的研究现状进行了评估,并对其未来发展进行了展望。

China's low-carbon transition for addressing climate change

This study discusses high-carbon characteristics, the unsustainability of China's development, and the fact that China needs to transform its development mode. China's low-carbon transition must include industry structure adjustment, energy saving and efficiency increases, energy structure improvement, carbon sink development, adaptation capability, and low-carbon pilot schemes.Low-carbon urbanization is a key measure in China's low-carbon transition. China's urbanization faces high-carbon risks. Thus, this study presents a roadmap for transforming urbanization into a low-carbon one. The transition to low-carbon urbanization is a common trend in the developing world. There is a lot of room for international cooperation.

Metamaterials: Reshape and Rethink

Metamaterials are composite materials whose material properties(acoustic, electrical, magnetic, or optical, etc.) are determined by their constitutive structural materials, especially the unit cells. The development of metamaterials continues to redefine the boundaries of materials science. In the field of electromagnetic research and beyond, these materials offer excellent design flexibility with their customized properties and their tunability under external stimuli. In this paper, we first provide a literature review of metamaterials with a focus on the technology and its evolution. We then discuss steps in the industrialization process and share our own experience.

A thermally tunable terahertz metamaterial absorber

A thermally tunable terahertz metamaterial absorber(MA) with InS b embedded in a metal-dielectric-metal structure is proposed. The transmission and tuning properties of the proposed metamaterial absorber are analyzed for the temperature ranging from 160 K to 350 K. The simulated results show that the maximum absorption of the absorber is nearly 99.8% at a full-width at half-maximum(FWHM) of 38 GHz, and the absorption frequency can be dynamically tuned from 0.82 THz to 1.02 THz.

Two Translations of Ji Yun＇s Close Scrutiny： the Translator, the Reader and the Settings of Translation

This article focuses on two English translations of Ji Yun＇s 纪昀 eigh- teenth-century collection of ＂stories of the strange,＂ Random Jottings at the Cottage of Close Scrutiny （Yuewei caotang biji 阅微草堂笔记）. The translation done by Leo Tak-hung Chan is set within the context of his 1998 sinological monograph, while David Pollard＇s recent translation, published in 2014, stands as an edited volume of translation oriented toward the general reader. Referring to textual and paratextual elements in these two translations, I hope to show how the ＂setting＂ of a translation modulates its tone and message, which in turn unfolds with the selection, style and overall structure of the translation. I also draw from an actual dialog between Leo Chan and David Pollard, which evolves around the various aspects in translating Ji Yun＇s work and the more general issues in sinology and translating Chinese literature. The dialog between the two translators of Ji Yun further illustrates the translators＇ approaches to the original text, their mediating efforts toward crosscultural readability and literary felicity and specifically, how the state of mind of a translator might come into play with the ＂flavor＂ of a translation.

Tuning crystal structure and magnetic property of dispersible FePt intermetallic nanoparticles

Dispersible FePt intermetallic nanopartides （NPs） with tunable composition were synthesized by thermal annealing of MgO coated A1-FePt （or A1-FePt-Fe304） NPs followed by an acid treatment to remove MgO. High-tem- perature annealing facilitates the conversion of FePt from disordered alloy to ordered intermetaUics. Under the protec- tion of MgO, the diffusion of Fe and Pt atoms was limited, making it possible for the atom reconstruction in the lattice to give discrete FePt intermetaUic NPs after a facile acid etching process. FePt intermetallic NPs formed face-centered cubic and face-centered tetragonal structures with their magnetic properties tuned by composition. The saturation magnetiza- tion was adjusted from 8 to 52 emu g^-1 by increasing the Fe concentration, while the coercivity reached a max/mum of 33 kOe when Fe concentration was 44%. After surface mod- ifications by hydrophilic or hydrophobic molecules containing thiol groups, FePt intermetallic NPs could be dissolved into water or hydrocarbon solvents. The hydrophilic L10-FePt in- termetallic NPs were applied as contrast agents for magnetic resonance imaging, showing a high transverse relaxivity of 328.6 mmo1^-1 L s^-l, which indicated the great potential of FePt intermetallic NPs as molecular probes for cancer diagnosis.

Dynamic metal patterns of wrinkles based on photosensitive layers

Regulating metal surfaces with micro-/nanoscale structures is of great significance for both material science and potential applications.However,the intrinsic properties of metals,such as fixed isotropic moduli and inflexible structures,in a sense present major limitations in developing next-generation smart patterned surfaces.In this work,a facile and general patterning strategy is proposed to endow insensitive metal surfaces with controllable spontaneous topologies and dynamic performance by exquisitely introducing an essential photosensitive interlayer.The arresting anthracene-containing photocrosslinking interlayer can selectively predetermine the anisotropic property of compliant bilayers without damaging metals’homogeneous properties,and realize a changeable stiff/soft layer.Furthermore,the mechanical transition mechanism of the self-adaptive wrinkling modes in metalbased trilayer systems is revealed to pave the pathway for regulating functional wrinkled metal surfaces.This photodriven metal patterning strategy can promote the development of brand-new methods for tuning the instability of multilayered materials,and be potentially applied in smart optical devices with dynamic reflectance,including light gratings and"magic"mirrors.

High-performance ultraviolet-visible tunable perovskite photodetector based on solar cell structure

An ultraviolet （UV）-visible tunable photodetec- tor based on ZnO nanorod arrays （NAs）/perovskite hetero- junction solar cell structures is presented, in which the ZnO NAs are prepared using the hydrothermal method and an- nealed in different atmospheres. Based on solar cell structure perovskite photodetectors, it exhibited highly repeatable and stable photoelectric response characteristics. In addition, the devices with ZnO NAs annealed in a vacuum showed a high responsivity of about 1014 cm Hz1/2 W-1 in the visible region, whereas the devices with ZnO NAs annealed in air exhib- Red good detectivity in the UV region, especially at around 350 nm. Furthermore, when the annealing atmosphere of the ZnO nanorods was changed from vacuum to air, the domi- nant detection region of the photodetectors was altered from the visible to the ultraviolet region. These results enable po- tential applications of the ZnO NAs/perovskite photodetec- tors in ultraviolet and visible regions.