一种新型有机质子响应荧光分子的合成在实验教学中的设计与探索

本实验将最新的科研热点——有机发光材料引入实验教学,开发了基于一个荧光分子二甲氨基苯乙烯基苯并噁唑的合成实验,并考查了其质子响应性质。本实验反应温和易控,操作简单,现象明显,绿色环保,并且可以用于模块化教学,拆分成多个环节实验,适合不同学时的实验教学要求,既可培养学生的基本操作,又能激发学生的实验兴趣,锻炼学生的综合能力。

Single-molecule optoelectronic devices:physical mechanism and beyond

Single-molecule devices not only promise to provide an alternative strategy to break through the miniaturization and functionalization bottlenecks faced by traditional semiconductor devices,but also provide a reliable platform for exploration of the intrinsic properties of matters at the single-molecule level.Because the regulation of the electrical properties of single-molecule devices will be a key factor in enabling further advances in the development of molecular electronics,it is necessary to clarify the interactions between the charge transport occurring in the device and the external fields,particularly the optical field.This review mainly introduces the optoelectronic effects that are involved in single-molecule devices,including photoisomerization switching,photoconductance,plasmon-induced excitation,photovoltaic effect,and electroluminescence.We also summarize the optoelectronic mechanisms of single-molecule devices,with particular emphasis on the photoisomerization,photoexcitation,and photo-assisted tunneling processes.Finally,we focus the discussion on the opportunities and challenges arising in the single-molecule optoelectronics field and propose further possible breakthroughs.

Hydrogenation of zirconium film by implantation of hydrogen ions

In order to understand the dnve-in target in a D-D type neutron generator,it is essential to study the mechanism of the interaction between hydrogen ion beams and the hydrogenabsorbing metal film.The present research concerns the nucleation of hydride within zirconium film implanted with hydrogen ions.Doses of 30 keV hydrogen ions ranging from 4.30×10^（17） to1.43×10^（18） ions cm^（-2） were loaded into the zirconium film through the ion beam implantation technique.Features of the surface morphology and transformation of phase structures were investigated with scanning electron microscopy,atomic force microscopy and x-ray diffraction.Confirmation of the formation of 5 phase zirconium hydride in the implanted samples was first made by x-ray diffraction,and the different stages in the gradual nucleation and growth of zirconium hydride were then observed by atomic force microscope and scanning electron microscopy.

Pharmacokinetics of gene recombined angiogenesis inhibitor Kringle 5 in vivo using 131I specific markers and SPECT/CT

The previous pharmacokinetic methods can be only limited to drug analysis in vitro, which provide less information on the distribution and metabolismof drugs, and limit the interpretation and assessment of pharmacokinetics, the determination of metabolic principles, and evaluation of treatment effect. The objective of the study was to investigate the pharmacokinetic characteristics of gene recombination angiogenesis inhibitor Kringle 5 in vivo. The SPECT/CT and specific^(131)I-Kringle 5 marked by Iodogen method were both applied to explore the pharmacokinetic characteristics of^(131)I-Kringle 5 in vivo, and to investigate the dynamic distributions of^(131)I-Kringle 5 in target organs. Labeling recombinant angiogenesis inhibitor Kringle 5 using131 I with longer half-life and imaging in vivo using SPECT instead of PET,could overcome the limitations of previous methods. When the doses of^(131)I-Kringle 5 were 10.0, 7.5 and5.0 g/kg, respectively, the two-compartment open models can be determined within all the metabolic process in vivo. There were no significant differences in t1/2α, t1/2β, apparent volume of distribution and CL between those three levels. The ratio of AUC(0 1)among three different groups of 10.0, 7.5 and 5.0 g/kg was 2.56:1.44:1.0, which was close to the ratio(2:1.5:1.0). It could be clear that in the range of 5.0–10.0 g/kg, Kringle 5 was characterized by the first-order pharmacokinetics. Approximately 30 min after^(131)I-Kringle 5 was injected,^(131)I-Kringle 5 could be observed to concentrate in the heart, kidneys, liver and other organs by means of planar imaging and tomography. After 1 h of being injected, more radionuclide retained in the bladder, but not in intestinal. It could be concluded that^(131)I-Kringle 5 is mainly excreted through the kidneys. About 2 h after the injection of^(131)I-Kringle 5, the radionuclide in the heart, kidneys,liver and other organs was gradually reduced, while more radionuclide was concentrated in the bladder.The radionuclide was completely metabolized within 24 h, and the distribution of radioactivity in rats was similar to normal levels. In our study, the specific marker^(131)I-Kringle 5 and SPECT/CT were successfully used to explore pharmacokinetic characteristics of Kringle 5 in rats. The study could provide a new evaluation platform of the specific, in vivo and real-time functional imaging and pharmacokinetics for the clinical application of^(131)I-Kringle 5.

基于侧基多通道和对称性破缺效应的分子电导调控

化学取代是有效调节分子电导,产生多通道输运、量子干涉效应和其他机制的关键方法.但分子骨架和侧基之间存在复杂的相互作用,目前仍未被研究清楚.在本工作中,我们结合扫描隧道显微镜裂结实验技术和第一性原理计算方法,深入研究了具有不同σ和π侧基的分子电导.实验结果及理论分析表明,σ侧基的加入引起了分子前线轨道的对称性破缺并加剧了分子内散射,从而导致电导的降低.相反,π侧基引入了额外的电荷传输通道,实现了电荷传输的多通道效应,增加了分子的电导.这些发现为未来分子功能化和分子电子器件的设计提供了坚实的基础.

氮掺杂单层石墨烯上无中间层沉积高质量氮化镓

在石墨烯/氧化铝衬底上通过金属有机化学气相沉积法(MOCVD)范德华外延生长的氮化镓(GaN)可以减少由于氮化镓与衬底严重晶格失配产生的缺陷.然而,石墨烯表面缺少悬挂键导致氮化镓成核位点很少,因此,常利用薄层AlN或ZnO纳米壁作为中间层沉积于石墨烯上.在无缓冲层的氮掺杂石墨烯上,我们利用MOCVD法成功地直接获得低应力(0.023 GPa)和低螺位错密度(9.76×10^(7)cm^(-2))的高质量氮化镓晶体.第一性原理计算结果表明,与本征石墨烯相比,氮掺杂石墨烯表面对镓原子的吸附能力明显提高,这与氮化镓低温生长成核实验观察到的结果一致.在大多数情况下,氮化镓在经过氮原子预处理的单层石墨烯上倾向于形成C-Ga-N和N-Ga-N的成核位点.本研究证明了通过界面调控可在氮掺杂石墨烯上生长高质量的氮化镓薄膜,是一种有效的原子调控方法.本方法为新型半导体器件的工业发展提供了新思路.

Physics-based,data-driven approach for predicting natural ventilation of residential high-rise buildings

Natural ventilation is particularly important for residential high-rise buildings as it maintains indoor human comfort without incurring the energy demands that air-conditioning does.To improve a building’s natural ventilation,it is essential to develop models to understand the relationship between wind flow characteristics and the building's design.Significantly more effort is still needed for developing such reliable,accurate,and computationally economical models instead of currently the most popular physics-based models such as computational fluid dynamics(CFD)simulation.This paper,therefore,presents a novel model developed based on physics-based modelling and a data-driven approach to evaluate natural ventilation in residential high-rise buildings.The model first uses CFD to simulate wind pressures on the exterior surfaces of a high-rise building.Once the surface pressures have been obtained,multizone modelling is used to predict the air change per hour(ACH)for different flats in various configurations.Data-driven prediction models are then developed using data from the simulation and deep neural networks that are based on mean absolute error,mean absolute percentage error,and a fusion algorithm respectively.These data-driven models are used to predict the ACH of 25 flats.The results from multizone modelling and data-driven modelling are compared.The results imply a high accuracy of the data-driven prediction in comparison with physics-based models.The fusion algorithm-based neural network performs best,achieving 96%accuracy,which is the highest of all models tested.This study contributes a more efficient and robust method for predicting wind-induced natural ventilation.The findings describe the relationship between building design(e.g.,plan layout),distribution of surface pressure,and the resulting ACH,which serve to improve the practical design of sustainable buildings.

Hybridized 1T/2H-MoS_(2)/graphene fishnet tube for high-performance on-chip integrated micro-systems comprising supercapacitors and gas sensors

The emerging micro-nano-processing technologies have propelled significant advances in multifunctional systems that can perform multiple functions within a small volume through integration.Herein,we present an on-chip multifunctional system based on a 1T/2H-MoS_(2)/graphene fishnet tube,where a micro-supercapacitor and a gas sensor are integrated.A hybrid three-dimensional stereo nanostructure,including M0S_(2) nanosheets and graphene fishnet tubes,provides K^(+)ions with a short diffusion pathway and more active sites.Owing to the large layer spacing of IT-M0S_(2) promoting fast reversible diffusion,the on-chip micro-supercapacitor exhibits excellent electrochemical properties,including an areal capacitance of 0.1 F·cm^(-2)(1 mV·s^(-1)).The variation in the conductivity of 2H-MoS_(2) when ammonia molecules are adsorbed as derived from the first-principles calculations proves the Fermi level-changes theory.Driven by a micro-supercapacitor,the responsivity of the gas sensor can reach 55.7%at room temperature(27℃).The multifunctional system demonstrates the possibility of achieving a two-dimensional integrated system for wearable devices and wireless sensor networks in the future.

Integrating Au and ZnO nanoparticles onto graphene nanosheet for enhanced sonodynamic therapy

Sonodynamic therapy has attracted widespread attention for cancer treatment because of its noninvasiveness and high tissuepenetration ability.Generally,ultrasound irradiation of sonosensitizers produces separated electrons(e−)and holes(h+),which inhibits cancer by producing reactive oxygen species(ROS).However,the separated electrons(e−)and holes(h+)could easily recombine,lowering the yield of ROS and hindering the application of sonodynamic therapy(SDT).Herein,we present a highly efficient sonosensitizer system for enhanced sonodynamic therapy built on reduced graphene oxide(rGO)nanosheets,bridged ZnO and Au nanoparticles,coated with polyvinyl pyrrolidone(PVP).The ultrasound irradiation activates ZnO nanoparticles to generate separated electron–hole(e−–h+)pairs,and the rGO nanosheets facilitate electron transfer from ZnO to Au nanoparticles because of the narrow band gap of rGO,which could efficiently restrain the recombination of the e−–h+pairs,thereby significantly augmenting the production of ROS to kill cancer cells,such as U373MG,HeLa,and CT26 cells.Moreover,rGO nanosheets integrated with Au nanoparticles could catalyze the endogenous decomposition of H_(2)O_(2) into O_(2),which can alleviate hypoxic tumor microenvironment(TME).Therefore,the rational design of Au-rGO-ZnO@PVP nanomaterials can not only improve the efficiency of sonodynamic therapy,but also mitigate the hypoxic tumor microenvironment,which would provide a new perspective in the development of efficient sonosensitizers.

Graphene Oxide Assemblies for Sustainable Clean-Water Harvesting and Green-Electricity Generation

CONSPECTUS:The urgent problems of water scarcity and the energy crisis have given rise to the development of a range of sustainable technologies with the great advancement of nanotechnologies and advent of attractive nanomaterials.Graphene oxides(GO),a derivative of graphene with an atom-thin thickness and abundant oxygen-containing functional groups(such as−OH,−COOH),are water-soluble and can be assembled into a variety of structures(such as fiber,membrane,and foam)with great potential in environmental and energy-related fields.As a typical precursor of graphene,GO can be easily reduced to graphene by chemical or thermal treatments to demonstrate excellent photothermal properties as well as tunable thermal conduction,which is highly desirable for efficient solar-driven water evaporation.The intrinsic large specific area of GO nanosheets can provide enough sites for ions adsorption and its porous assemblies facilitate the transport of water.In addition,the abundant functional groups allow the spontaneous adsorption of water molecules from the ambient environment and give birth to movable ions(usually protons)under the solvation effect.Once a chemical gradient is formed on the component,a remarkable electricity is generated from the directional transport of protons.Thanks to the excellent chemical properties of GO nanosheets,a wide range of assemblies with 1D aligned fibers,2D layered membranes and 3D porous foam can be easily fabricated by wet-spinning,solution-filtration,and freezingdrying methods.The various GO assemblies are able to exhibit abundant functions with remarkable weaving capability for GO fibers,superior flexibility for GO membranes,and exceptional adsorption capacity for GO foams.In light of all the advantages,GO and its assemblies are remarkably promising in the fields of sustainable development to meet the pressing challenges of water and energy crisis.In this Account,we will discuss the progress of clean-water production and green-electricity generation technologies based on GO assemblies.The fundamental working mechanism,optimization strategies,and promising applications are explored with an emphasis on the materials development.We also discuss the functions of GO assemblies in the water and electricity generation process and present their limitations and possible solutions.Current challenges and promising directions for the development of clean-water production and green-electricity generation are also demonstrated for their realistic implementations.We anticipate that this Account would promote more efforts toward fundamental research on graphene functionalization and encourage a broad exploration on the application of graphene assemblies in clean-water production and electric power generation systems.