火焰原子吸收光谱测定葡萄糖酸锌口服液中锌含量

“火焰原子吸收光谱”是本科生仪器分析实验教学中的重要实验之一。原子吸收光谱用于实际样品中某一特定元素的定量测定,具有测定准确度高、精密度高和选择性好等优点。葡萄糖酸锌口服液是生活中常见的口服补锌类非处方药,通过本科生自主实验,建立火焰原子吸收实验方法,测定葡萄糖酸锌口服液中锌含量,方法简便、易于操作。通过该自主实验,培养学生利用课堂所学理论知识解决实际问题的能力,实现“学以致用,用以促学”的育人目标。

输电线路发生单相接地短路后采样周期对测距精度的影响

本文分析了输电线路三相系统发生单相接地短路故障时工频测距的基本原理。选用PSCAD/EMTDC仿真软件搭建输电线路分布参数模型,针对输电线路发生单相接地短路故障进行仿真,使用傅立叶算法对故障周期进行提取并计算电压电流工频量,利用基于工频分量的单端故障测距原理进行故障测距。分析利用傅立叶算法在提取电压电流工频量时选取不同采样周期对测距精度的影响。借助福建霞浦小沙110 KV大京风电线发生单相接地短路故障时,录波器采集到的实时故障数据,验证采样周期对测距结果的影响。对利用工频量进行故障测距时采样周期的选取有一定的借鉴意义。

Gate-tunable high-performance broadband phototransistor array of two-dimensional PtSe_(2) on SOI

Two-dimensional(2D)layered materials have attracted extensive research interest in the field of high-performance photodetection due to their high carrier mobility,tunable bandgap,stability,other excellent properties.Herein,we propose a gate-tunable,high-performance,self-driving,wide detection range phototransistor based on a 2D PtSe_(2)on silicon-oninsulator(SOI).Benefiting from the strong built-in electric field of the PtSe_(2)/Si heterostructure,the phototransistor has a fast response time(rise/fall time)of 36.7/32.6μs.The PtSe_(2)/Si phototransistor exhibits excellent photodetection performance over a broad spectral range from ultraviolet to near-infrared,including a responsivity of 1.07 A/W and a specific detectivity of 6.60×10^(9)Jones under 808 nm illumination at zero gate voltage.The responsivity and specific detectivity of PtSe_(2)/Si phototransistor at 5 V gate voltage are increased to 13.85 A/W and 1.90×10^(10) Jones under 808 nm illumination.Furthermore,the fabricated PtSe_(2)/Si phototransistor array shows excellent uniformity,reproducibility,long-term stability in terms of photoresponse performance with negligible variation between pixel cells.The architecture of present PtSe_(2)/Si on SOI platform paves a new way of a general strategy to realize high-performance photodetectors by combining the advantages of both 2D materials and conventional semiconductors which is compatible with current Si-complementary metal oxide semiconductor(CMOS)process.

具有超薄Al_(2)O_(3)钝化层的高性能近红外PtSe_(2)/n-Ge异质结光电探测器

二维(2D)材料正被广泛用于宽带响应光电探测器(PD).然而,基于2D材料的宽带响应PD通常对红外波长的响应较差.在此,我们报告了垂直PtSe_(2)/超薄Al_(2)O_(3)/Ge PD在近红外照明下的优异光响应性能.我们直接硒化沉积在Al_(2)O_(3)/Ge上的Pt膜以形成PtSe_(2)层.超薄Al_(2)O_(3)钝化层起到表面改性的作用,有效地削弱了光生载流子的复合.在1550 nm的光照下,我们的PtSe_(2)/超薄Al_(2)O_(3)/Ge PD的工作面积为50μm×50μm,并在零偏压下获得了4.09 A W^(-1)、32.6/18.9μs的大响应度和快速上升/下降时间.在-5 V的外加电压下,PtSe_(2)/超薄Al_(2)O_(3)/Ge PD的响应度和响应速度分别高达38.18 A W^(-1)和9.6/7.7μs.我们发现器件的工作面积对光响应特性有很大的影响.此外,我们证明PtSe_(2)/超薄Al_(2)O_(3)/Ge PD阵列在室温下显示出了优异的紫外、可见光和红外成像能力.我们的研究表明,PtSe_(2)/超薄Al_(2)O_(3)/Ge异质结在设计具有优异近红外响应性能的新兴宽带光电子器件方面具有巨大的应用前景.

High performance IEICO-4F/WSe_(2)heterojunction photodetector based on photoluminescence quenching behavior

Heterostructure is the basic building block for functional optoelectronic devices.Heterostructures consisting of two-dimensional(2D)transition metal dichalcogenides(TMDs)and organic semiconductors are currently attracting great interest for highperformance optoelectronics.However,how to design heterostructure for highly efficient optoelectronic devices remains a big challenge.Here we design high-performance organic semiconductor/WSe_(2)heterostructure photodetectors by tailoring the charge transfer effect between 2,2ʹ-((2Z,2ʹZ)-(((4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydros-indaceno[1,2-b:5,6-bʹ]dithiophene-2,7-diyl)bis(4-((2-ethylhexyl)oxy)thiophene-5,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(IEICO-4F)organic semiconductors with various thicknesses and monolayer WSe_(2).With the increase of IEICO-4F layer thickness,the photoluminescence(PL)characteristics of WSe_(2)could be completely quenched due to the charge transfer from the lowest unoccupied molecular orbital(LUMO)level of IEICO-4F to the conduction band minimum(CBM)of WSe_(2).Benefiting from the exquisite charge transfer behavior,the IEICO-4F/WSe_(2)heterojunction photodetector with optimized 6.0-nm thick IEICO-4F shows high performance including the responsivity of 8.32 A/W and specific detectivity of 4.65×10^(11)Jones at incident light of 808 nm.This work demonstrates a simple approach based on PL characteristics to design high-performance IEICO-4F/WSe_(2)heterojunction,thus paving the way for the development of excellent optoelectronic devices based on organic/TMD heterostructures.

Monolithic integration of nanorod arrays on microfluidic chips for fast and sensitive one-step immunoassays

Here,we present integrated nanorod arrays on microfluidic chips for fast and sensitive flow-through immunoassays of physiologically relevant macromolecules.Dense arrays of Au nanorods are easily fabricated through one-step oblique angle deposition,which eliminates the requirement of advanced lithography methods.We report the utility of this plasmonic structure to improve the detection limit of the cardiac troponin I(cTnI)assay by over 6x 105-fold,reaching down to 33.9fg mL^(-1)(-1.4fM) compared with an identical assay on glass substrates.Through monolithic integration with microfluidic elements,the device enables a flow-through assay for quantitative detection of cTnI in the serum with a detection sensitivity of 6.9 pg mL^(-1)(-0.3 pM)in<6 min,which was 4000 times lower than conventional glass devices.This ultrasensitive detection arises from the large surface area for antibody conjugation and metal-enhanced fluorescent signals through plasmonic nanostructures.Moreover,due to the parallel arrangement of flow paths,simultaneous detection of multiple cancer biomarkers,including prostate-specific antigen and carcinoembryonic antigen,has been fulfilled with increased signal-to-background ratios.Given the high performance of this assay,together with its simple fabrication process that is compatible with standard mass manufacturing techniques,we expect that the prepared integrated nanorod device can bring on-site point-of-care diagnosis closer to reality.

Enhanced Photocatalytic Performance of Surface-Modified TiO_(2) Nanofibers with Rhodizonic Acid

The improvement of the photocatalytic performance of TiO_(2) nanofibers(NFs),prepared by electrospinning,is achieved by surface modification with the rhodizonic acid(RhA).The condensation reaction between hydroxyl groups from TiO_(2) NFs and RhA is accompanied by the red-shift of optical absorption due to interfacial charge transfer(ICT)complex formation.Crystal structure,morphology,and optical properties of unmodified and surface-modified TiO_(2) NFs were analyzed.The photocatalytic performance of prepared samples has been examined through degradation of organic dye methylene blue.Superior photocatalytic activity of surface-modified TiO_(2) NFs with RhA is attributed to their enhanced optical properties,i.e.,the ability to harvest the photon energy in the visible spectral range.