Microwave-assisted synthesis and characterization of ZnO-nanorod arrays

High density ZnO-nanorod arrays(rod length 1.59μm)were successfully synthesized via a microwave-assisted solution-phase method using zinc chloride and ammonia solution as reactants.The influence of concentration of ammonia solution, work power,and microwave irradiation time on the morphology and size of final products was carefully investigated.The crystal structure,chemical composition and morphologies of final products were characterized using X-ray powder diffraction(XRD), scanning electron microscopy(SEM)and photoluminescence(PL).The as-synthesized ZnO is composed of single crystalline and possesses three photoluminescence emissions centered at 400,469 and 534.5 nm,respectively.

Deep brain implantable microelectrode arrays for detection and functional localization of the subthalamic nucleus in rats with Parkinson’s disease

The subthalamic nucleus(STN)is considered the best target for deep brain stimulation treatments of Parkinson’s disease(PD).It is difficult to localize the STN due to its small size and deep location.Multichannel microelectrode arrays(MEAs)can rapidly and precisely locate the STN,which is important for precise stimulation.In this paper,16-channel MEAs modified with multiwalled carbon nanotube/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(MWCNT/PEDOT:PSS)nanocomposites were designed and fabricated,and the accurate and rapid identification of the STN in PD rats was performed using detection sites distributed at different brain depths.These results showed that nuclei in 6-hydroxydopamine hydrobromide(6-OHDA)-lesioned brains discharged more intensely than those in unlesioned brains.In addition,the MEA simultaneously acquired neural signals from both the STN and the upper or lower boundary nuclei of the STN.Moreover,higher values of spike firing rate,spike amplitude,local field potential(LFP)power,and beta oscillations were detected in the STN of the 6-OHDA-lesioned brain,and may therefore be biomarkers of STN localization.Compared with the STNs of unlesioned brains,the power spectral density of spikes and LFPs synchronously decreased in the delta band and increased in the beta band of 6-OHDA-lesioned brains.This may be a cause of sleep and motor disorders associated with PD.Overall,this work describes a new cellular-level localization and detection method and provides a tool for future studies of deep brain nuclei.

A novel self-alignment method for high precision silicon diffraction microlens arrays preparation and its integration with infrared focal plane arrays

Silicon(Si)diffraction microlens arrays are usually used to integrating with infrared focal plane arrays(IRFPAs)to improve their performance.The errors of lithography are unavoidable in the process of the Si diffrac-tion microlens arrays preparation in the conventional engraving method.It has a serious impact on its performance and subsequent applications.In response to the problem of errors of Si diffraction microlens arrays in the conven-tional method,a novel self-alignment method for high precision Si diffraction microlens arrays preparation is pro-posed.The accuracy of the Si diffractive microlens arrays preparation is determined by the accuracy of the first li-thography mask in the novel self-alignment method.In the subsequent etching,the etched area will be protected by the mask layer and the sacrifice layer or the protective layer.The unprotection area is carved to effectively block the non-etching areas,accurately etch the etching area required,and solve the problem of errors.The high precision Si diffraction microlens arrays are obtained by the novel self-alignment method and the diffraction effi-ciency could reach 92.6%.After integrating with IRFPAs,the average blackbody responsity increased by 8.3%,and the average blackbody detectivity increased by 10.3%.It indicates that the Si diffraction microlens arrays can improve the filling factor and reduce crosstalk of IRFPAs through convergence,thereby improving the perfor-mance of the IRFPAs.The results are of great reference significance for improving their performance through opti-mizing the preparation level of micro nano devices.

Manipulating d-d orbital hybridization induced by Mo-doped Co_(9)S_(8) nanorod arrays for high-efficiency water electrolysis

Precisely refining the electronic structure of electrocatalysts represents a powerful approach to further optimize the electrocatalytic performance.Herein,we demonstrate an ingenious d-d orbital hybridization concept to construct Mo-doped Co_(9)S_(8) nanorod arrays aligned on carbon cloth(CC)substrate(abbreviated as Mo-Co_(9)S_(8)@CC hereafter)as a high-efficiency bifunctional electrocatalyst toward water electrolysis.It has experimentally and theoretically validated that the 4d-3d orbital coupling between Mo dopant and Co site can effectively optimize the H_(2)O activation energy and lower H^(*)adsorption energy barrier,thereby leading to enhanced hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)activities.Thanks to the unique electronic and geometrical advantages,the optimized Mo-Co_(9)S_(8)@CC with appropriate Mo content exhibits outstanding bifunctional performance in alkaline solution,with the overpotentials of 75 and 234 mV for the delivery of a current density of 10 mA cm^(-2),small Tafel slopes of 53.8 and 39.9 mV dec~(-1)and long-term stabilities for at least 32 and 30 h for HER and OER,respectively.More impressively,a water splitting electrolylzer assembled by the self-supported Mo-Co_(9)S_(8)@CC electrode requires a low cell voltage of 1.53 V at 10 mA cm^(-2)and shows excellent stability and splendid reversibility,demonstrating a huge potential for affordable and scalable electrochemical H_(2) production.The innovational orbital hybridization strategy for electronic regulation herein provides an inspirable avenue for developing progressive electrocatalysts toward new energy systems.

短周期密集台阵深部地壳结构探测研究进展

由于穿透能力强,天然地震接收函数成为壳幔结构探测中最为广泛使用的方法.随着人们对地球内部结构和动力学过程认识程度的提高,台间距相对较大的宽频带台阵已无法满足壳幔结构高分辨率探测的需求.短周期密集台阵采用频率较高的便携式数字地震仪,通过百米级台间距的密集观测,可在短时间内(1~2个月)获得大量地震数据.其优势主要表现在三个方面:(1)地壳内射线交叉覆盖好,有利于提高分辨率;(2)射线密集分布,通过相干叠加压制噪声,可实现高频接收函数的成像;(3)观测时间短,效率高.因此,短短几年内,短周期密集台阵已经成为地壳深部结构探测的常规手段之一.本文主要介绍短周期密集台阵深部地壳结构探测的由来,以及通过几个典型的探测实例,展示探测效果及其在不同构造域的应用.

Effect of KOH treatment on structural and photovoltaic properties of ZnO nanorod arrays

ZnO nanorod arrays （NRs） were synthesized on the fluorine-doped SnO2 transparent conductive glass （FTO） by a simple chemical bath deposition （CBD） method combined with alkali-etched method in potassium hydroxide （KOH） solution. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and current-voltage （I-V） curve were used to characterize the structure, morphologies and optoelectronic properties. The results demonstrated that ZnO NRs had wurtzite structures, the morphologies and photovoltaic properties of ZnO NRs were closely related to the concentration of KOH and etching time, well-aligned and uniformly distributed ZnO NRs were obtained after etching with 0.1 mol/L KOH for 1 h. ZnO NRs treated by KOH had been proved to have superior photovoltaic properties compared with high density ZnO NRs. When using ZnO NRs etched with 0.1 mol/L KOH for 1 h as the anode of solar cell, the conversion efficiency, short circuit current and open circuit voltage, compared with the unetched ZnO NRs, increased by 0.71%, 2.79 mA and 0.03 V, respectively.

Design and Characteristics of InGaAs/GaAs MQW SEED Arrays Structure

The influence of DBR in resonant cavity on the characteristics of the reflectivity of InGaAs/GaAs MQW SEED arrays has been discussed. InGaAs/GaAs acting as the active region of MQW SEED to gain 980nm work wavelergth has been introduced. A new resonant cavity structure of the InGaAs/GaAs MQW SEED arrays has been designed and analyzed. The MQW materials grown by MOCVD system have also been measured and analyzed with micro optical spot reflection spectra, PL measurement and X ray measurement. The results of measurement prove the good quality of the wafer and the accuracy of our design and analysis of the structure of the device.

Computation of strain and rotation tensor as well as their uncertainties for small arrays in spherical coordinate system

Based on Taylor series expansion and strain components expressions of elastic mechanics, we derive formulae of strain and rotation tensor for small arrays in spherical coordinates system. By linearization process of the formulae, we also derive expressions of strain components and Euler vector uncertainties respectively for subnets using the law of error propagation. Taking GPS velocity field in Sichuan-Yunnan area as an example, we compute dilation rate and maximum shear strain rate field using the above procedure, and their characteristics are preliminarily car- ried on. Limits of the strain model for small array are also discussed. We make detailed explanations on small array method and the choice of small arrays. How to set weights of GPS observations are further discussed. Moreover relationship between strain and radius of GPS subnets is also analyzed.

密集台阵主动源与被动源联合探测珠三角地壳结构

基于密集台阵的远震接收函数探测与人工地震测深使用相同的观测系统、观测仪器,人工地震测深的优势在于构建地壳上地幔精细速度结构模型,密集台阵接收函数成像的优势在于构建地壳几何结构模型,密集台阵主动源与被动源的联合探测方法可以有效地扩展和提升深部探测的成果和认识.本研究使用珠三角地区人工地震测深L1测线的连续数据,开展了被动源远震接收函数成像研究,联合人工地震测深获得的地壳P波速度结构模型,构建了L1测线下方的地壳几何结构模型以及地壳平均波速比分布,揭示了珠三角西岸的地壳结构和断裂带的特征,主要包括:(1)地壳厚度28~30 km,过吴川—四会断裂后向东南方向减薄;(2)地壳平均波速比在测线中部吴川—四会断裂附近为~1.73,两侧小于1.70;(3)中地壳内存在低速构造,横向上被恩平—开平断裂带分隔.基于上述结果认为珠三角地区的地壳经历过明显的减薄作用,偏低的地壳平均波速比和下地壳V_(P)说明主要由下地壳减薄导致,推测吴川—四会断裂和恩平—开平断裂深部向东倾斜,并深切至Moho面,断裂带的形成演化受控于区域岩石圈地幔的热隆作用以及东南向的伸展作用.基于密集台阵的主动源与被动源联合探测方法,能为认识精细的地壳上地幔结构特征提供多参数、多尺度的约束,对刻画界面属性、断裂延伸、流熔体分布等都有重要指示意义,在深部结构探测和矿产资源勘查等领域具有广阔的应用前景.

Octahedral Cu_2O-modified TiO_2 nanotube arrays for efficient photocatalytic reduction of CO_2

A photocatalyst composed of TiO 2 nanotube arrays（TNTs） and octahedral Cu2 O nanoparticles was fabricated,and its performance in the photocatalytic reduction of CO2 under visible and simulated solar irradiation was studied. The average nanotube diameter and length was 100 nm and 5 μm,respectively. The different amount of octahedral Cu2 O modified TNTs were obtained by varying electrochemical deposition time. TNTs modified with an optimized amount of Cu2 O nanoparticles exhibited high efficiency in the photocatalysis,and the predominant hydrocarbon product was methane. The methane yield increased with increasing Cu2 O content of the catalyst up to a certain deposition time,and decreased with further increase in Cu2 O deposition time. Insufficient deposition time（5 min） resulted in a small amount of Cu2 O nanoparticles on the TNTs,leading to the disadvantage of harvesting light. However,excess deposition time（45 min） gave rise to entire TNT surface being most covered with Cu2 O nanoparticles with large sizes,inconvenient for the transport of photo-generated carriers. The highest methane yield under simulated solar and visible light irradiation was observed for the catalysts prepared at a Cu2 O deposition time of 15 and 30 min respectively. The morphology,crystallization,photoresponse and electrochemical properties of the catalyst were characterized to understand the mechanism of its high photocatalytic activity. The TNT structure provided abundant active sites for the adsorption of reactants,and promoted the transport of photogenerated carriers that improved charge separation. Modifying the TNTs with octahedral Cu2 O nanoparticles promoted light absorption,and prevented the hydrocarbon product from oxidation. These factors provided the Cu2O-modified TNT photocatalyst with high efficiency in the reduction of CO2,without requiring co-catalysts or sacrificial agents.

骨组织工程中传统与仿生支架结构设计的差异

背景:多孔支架作为新骨生长的临时基质在骨修复过程中起着关键作用,其中多孔支架的结构设计是骨修复过程中的研究重点。目的:综述传统支架(规则、均匀的支架)和仿生支架(不规则、不均匀的支架)在骨组织工程研究领域的应用。方法:检索中国知网(CNKI)、维普、万方、Web of Science、Science Direct、PubMed、EI等数据库,选取2008年1月至2024年3月发表的文献,中文检索词为“骨组织工程,仿生支架,骨小梁,传统支架,骨修复,三周期极小曲面”,英文检索词为“bone tissue engineering,bionic scaffolds,bone trabeculae,traditional scaffolds,bone repair,TPMS”。最终纳入81篇文献进行综述。结果与结论:骨支架的结构设计是实现骨修复和骨再生的关键,骨组织工程中的支架技术已取得显著进展。传统的规则多孔支架因简单的制造流程和良好的机械性能被广泛应用,然而这类支架往往缺乏生物活性,难以模拟自然骨组织的复杂微环境,限制了其在促进细胞增殖和骨再生方面的能力。相反,仿生支架通过模拟自然骨组织的结构特征,提供了更适宜的生理微环境,促进了成骨细胞的增殖、分化及新骨的形成,为骨缺损有效治疗提供了新的思路。尽管仿生支架在理论上具有巨大的潜力,但在实际应用中仍面临诸多挑战,支架的生物相容性、生物活性及长期稳定性等因素仍需通过临床试验进行进一步验证。

基于光电对射阵列下谷物收获流量控制系统的设计

在谷物收获过程中,由于谷物的性质不同及收获机械的工作状态不同,谷物的流量往往会出现波动或过大过小的情况,直接影响谷物的收获效率和质量,甚至会导致收获机械的故障。因此,对谷物的流量进行准确的控制和调节是非常重要的。为此,设计了一种基于光电对射阵列的谷物收获流量控制系统,可通过使用光电对射阵列检测收获机的运动状态和收获物料的流量,进而控制收获机的速度和工作状态,以实现谷物的准确收获和控制流量。试验验证表明:系统具有较高的准确性和稳定性,能够有效地控制谷物的流量,提高收获效率和质量,具有广泛的应用前景。

Nanostructured ultrathin catalyst layer with ordered platinum nanotube arrays for polymer electrolyte membrane fuel cells

Fabrication of novel electrode architectures with nanostructured ultrathin catalyst layers is an effective strategy to improve catalyst utilization and enhance mass transport for polymer electrolyte membrane fuel cells (PEMFCs).Herein,we report the design and construction of a nanostructured ultrathin catalyst layer with ordered Pt nanotube arrays,which were obtained by a hard-template strategy based on ZnO,via hydrothermal synthesis and magnetron sputtering for PEMFC application.Because of the crystallographically preferential growth of Pt (111) facets,which was attributed to the structural effects of ZnO nanoarrays on the Pt nanotubes,the catalyst layers exhibit obviously higher electrochemical activity with remarkable enhancement of specific activity and mass transport compared with the state-of-the-art randomly distributed Pt/C catalyst layer.The PEMFC fabricated with the as-prepared catalyst layer composed of optimized Pt nanotubes with an average diameter of 90(±10) nm shows excellent performance with a peak power density of 6.0W/mgPt at 1 A/cm^2,which is 11.6%greater than that of the conventional Pt/C electrode.

THE INTERACTION BETWEEN SHOCK WAVES AND SOLID SPHERES ARRAYS IN A SHOCK TUBE

When a shock wave interacts with a group of solid spheres,non-linear aerodynamic behaviors come into effect.The complicated wave reflections such as the Mach reflection occur in the wave propagation process.The wave interactions with vortices behind each sphere's wake cause fluctuation in the pressure profiles of shock waves.This paper reports an experimental study for the aerodynamic processes involved in the interaction between shock waves and solid spheres.A schlieren photography was applied to visualize the various shock waves passing through solid spheres.Pressure measurements were performed along different downstream positions.The experiments were conducted in both rectangular and circular shock tubes.The data with respect to the effect of the sphere array, size,interval distance,incident Mach number,etc.,on the shock wave attenuation were obtained.

Short-wave infrared InGaAs photodetectors and focal plane arrays

In this article, unique spectral features of short-wave infrared band of 1 μm–3 μm, and various applications related to the photodetectors and focal plane arrays in this band, are introduced briefly. In addition, the different material systems for the devices in this band are outlined. Based on the background, the development of lattice-matched and wavelengthextended InGaAs photodetectors and focal plane arrays, including our continuous efforts in this field, are reviewed. These devices are concentrated on the applications in spectral sensing and imaging, exclusive of optical fiber communication.

Characterization of integrons and novel cassette arrays in bacteria from clinical isloates in China,2000-2014

Rapid dissemination of antibiotic resistance genes among bacterial isolates is an increasing problem in China. Integron, a conserved DNA sequence, which is carried on episomal genetic structures, plays a very important role in development of antibiotic resistance. This systematic analysis was based on MEDLINE and EMBASE databases. We summarized the distribution and proportion of different types of gene cassette arrays ofintegrons （including class 1, 2, 3 and atypical class 1 integron） from clinical bacteria isolates in China. Fifty-six literatures were included in this study. Most of the strains were Gram-negative bacteria （94.1%, 7,364/7,822） while only 5.9% strains were Gram- positive bacteria. Class 1 integrons were detected in 54.2% （3956/7295） Gram-negative strains, aadA2 was the most popular gene cassette array detected from 60 Gram-positive bacteria while dfrA 17-aadA5 were detected in 426 Gram- negative bacteria. This study identified 12 novel gene cassette arrays which have not been previously found in any species. All the novel gene cassette arrays were detected from Gram-negative bacteria. A regional characteristic of distribution of integrons was presented in this study. The results highlight a need for continuous surveillance of integrons and provide a guide for future research on integron-mediated bacteria resistance.

A Hybrid Electrode of Co_3O_4@PPy Core/Shell Nanosheet Arrays for High-Performance Supercapacitors

Herein, combining solverthermal route and electrodeposition, we grew unique hybrid nanosheet arrays consisting of Co_3O_4 nanosheet as a core, PPy as a shell. Benefiting from the PPy as conducting polymer improving an electron transport rate as well as synergistic effects from such a core/shell structure, a hybrid electrode made of the Co_3O_4@PPy core/shell nanosheet arrays exhibits a large areal capacitance of 2.11 F cm-2at the current density of 2 m A cm^(-2), a *4-fold enhancement compared with the pristine Co_3O_4electrode; furthermore, this hybrid electrode also displays good rate capability(*65 % retention of the initial capacitance from 2 to 20 m A cm^(-2)) and superior cycling performance(*85.5 % capacitance retention after 5000 cycles). In addition, the equivalent series resistance value of the Co_3O_4@PPy hybrid electrode(0.238 X) is significantly lower than that of the pristine Co_3O_4electrode(0.319 X). These results imply that the Co_3O_4@PPy hybrid composites have a potential for fabricating next-generation energy storage and conversion devices.

Directional construction of Cu2S branch arrays for advanced oxygen evolution reaction

Metal sulphide electrocatalyst is considered as one of the most promising low-cost candidates for oxygen evolution reaction(OER).In this work,we report a novel free-standing Cu2S branch array via a facile TiO2-induced electrodeposition-sulfurization method.Interestingly,cross-linked Cu2S nanoflake branch is strongly anchored on the TiO2 backbone forming high-quality Cu2S/TiO2/Cu2S core-branch arrays.The branch formation mechanism is also proposed.As compared to the pure Cu2S nanowire arrays,the asprepared Cu2S/TiO2/Cu2S core-branch arrays show much better alkaline OER performance with lower overpotential(284 mV at 10 mA cm^-2)and smaller Tafel slope(72 dec-1)as well as enhanced longterm durability mainly due to larger exposed area and more active electrocatalytic sites.Our work provides a new way for construction of advanced metal sulphide electrocatalysts for electrochemical energy conversion.

Hydrothermal growth of well-aligned TiO_2 nanorod arrays: Dependence of morphology upon hydrothermal reaction conditions

Well-aligned TiO2 nanorod arrays （TNAs） were prepared on pretreated quartz substrates via hydrothermal method.The effect of the different preparation conditions on the growth morphologies of TNAs was systematically investigated by X-ray diffraction （XRD） and field-emission scanning electron microscopy （FE-SEM）.The photocatalytic properties were tested by photodegradation of a methyl blue solution.It is demonstrated that the hydrothermal reaction conditions,such as precursor concentration,hydrothermal reaction temperature,and hydrothermal reaction times,can greatly affect the growth of TNAs.Controlling the preparation process,TNAs with 2 μm in length and 140-170 nm in diameter and well-aligned orientation have been successfully prepared.The photocatalytic experiment results indicate that TNAs have much better photocatalytic activity than TiO2 nanoparticles.

Electrochemical Preparation and Photoelectric Properties of Cu_2O-loaded TiO_2 Nanotube Arrays

TiO2 nanotube （TNT） arrays were fabricated by anodic oxidation of titanium foil in a fluoride- based solution, on which Cu20 particles were loaded via galvanostatic pulse electrodeposition in cupric acetate solutions in the absence of any other additives. The structure and optical properties of Cu2O-loaded TiO2 nanotube arrays （Cu2O-TNTs） were analyzed by scanning electron microscopy （SEM）, X-ray diffraction （XRD） and UV-Vis absorption, and the photoelectrochemical performance was measured using an electrochemical work station with a three-electrode configuration. The results show that the Cu2O particles distribute uniformly on the highly ordered anatase TiO2 nanotube arrays. The morphologies of Cu2O crystals change from branched, truncated octahedrons to dispersive single octahedrons with increasing deposition current densities. The Cu2O- TNTs exhibited remarkable visible light responses with obvious visible light absorption and greatly enhanced visible light photoelectrochemical performance. The I-V characteristics under visible light irradiation show a distinct plateau in the region between approximately -0.3 and 0 V, resulting in higher open-circuit voltages and larger short-circuit currents with increased Cu2O deposition.