Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2022-10-04
Abstract: Nanotechnology has provided considerable promise for the biological and medical fields, especially in the subjects of biological and medical imaging for the last two decades. Here, we outline different nanoparticles to contribute to biological and medical imaging disciplines. These concerned nanoparticles are soft nanoparticles, which are based on biomacromolecule/polymer or organic molecule components, hard nanoparticles that are derived from various inorganic components and hard-soft nanoparticles that are based on both inorganic components and biomacromolecule/polymer or organic molecule ones. We also discuss the imaging modalities in biology and medicine that various nanoparticles became involved in are: (1) optical imaging (OI), (2) computed tomography (CT), (3) magnetic resonance imaging (MRI), (4) ultrasonography (USG), (5) positron emission tomography (PET). We will also describe various nanoparticles to serve for one/some of those five modalities in biology and medicine imaging in this review paper.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2021-03-26
Abstract: Solar stills have attracted increasing attentions in recent years due to its ability of simple construction and eco-friendly. In this study, the weighted values of environment factors on evaporation efficiency are obtained by using a well-established machine learning algorithm, random forest. To test the advancement between random forest and mathematical data analysis, two traditional data science methods, pair wise plots and Pearson correlation analysis, were conducted for comparison. Experimental data used in analysis were collected from around 100 articles since 2014. The results indicated that thermal design was the most significant factor that contributes in high-efficiency solar evaporation. It will promote the studies on evaporation efficiency solar stills. "
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-05-09
Abstract: The Gd-Fe-Al amorphous/nanocrystalline composites were successfully designed and obtained with both high Curie temperature [T-c] and large magnetic entropy change [Delta S-M]. The Tc can be tuned from 172 to 280 K and refrigeration capacity [RC] has a val
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-05-07
Abstract:In this paper a kind of copper oxide material of copper–polyphenols complex nanoparticles (Cu–P NPs) were synthesized by Cinnamomum pedunculatum leaves extract, which have different morphology and appearance compared with usual copper oxides Cu2O and CuO. For better understanding about this material, the Cu–P NPs were characterized using scanning electron microscopy (SEM), X-ray absorption spectroscopy (XAS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). It was found that synthesized Cu–P NPs were amorphous with spherical particles ranged from 80 to 500 nm. XAS data analysis indicated that the synthesized Cu–P NPs has different molecular structure with Cu2O and CuO. It is assumed that the copper ions chelated with polyphenol molecule. The nanoparticles showed a clear anti Escherichia coli activity in this study, and may also be used in fields of semiconductor, ceramic, catalyst, and sensor. This synthesis approach provided a novel route to manufacture copper oxide nanomaterial.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-03-30
Abstract: Electrochemical performances of multi-walled carbon nanotubes (CNT)-SiCN composite have been investigated. The sample was synthesized by a simple ultrasonication assisted method combined with high-temperature pyrolysis and characterized by Fourier transfo
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-03-30
Abstract: Low-voltage (1.5 V) indium zinc oxide (IZO)-based electric-double-layer (EDL) thin-film transistors (TFTs) gated by nanogranular proton conducting SiO2 electrolyte films are fabricated on paper substrates. Both enhancement-mode and depletion-mode operatio
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-03-30
Abstract: Ozone treatment is a common way to functionalize commercial multi-walled carbon nanotubes (CNTs) with various oxygen functionalities like carboxyl, phenol and lactone groups, in order to enhance their textural properties and chemical activity. In order to
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-03-30
Abstract: Electrochemical performances of multi-walled carbon nanotubes (CNT)-SiCN composite have been investigated. The sample was synthesized by a simple ultrasonication assisted method combined with high-temperature pyrolysis and characterized by Fourier transfo
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-03-30
Abstract: Low-voltage (1.5 V) indium zinc oxide (IZO)-based electric-double-layer (EDL) thin-film transistors (TFTs) gated by nanogranular proton conducting SiO2 electrolyte films are fabricated on paper substrates. Both enhancement-mode and depletion-mode operatio
Peer Review Status:Awaiting Review
Subjects: Physics >> Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-02-23
Abstract:The hexagonal boron nitride (h-BN) nanosheets are synthesized by the liquid-phase exfoliation method and transferred onto the microfiber by optical deposition method. The h-BN-deposited microfiber exhibits dual-function, that is, saturable absorption and high-nonlinearity. To check the laser performance by using the proposed h-BN device, it is inserted into an erbium-doped fiber laser (EDFL). In experiment, we demonstrate a tunable, switchable dual-wavelength soliton pulse by properly adjusting the pump power and the polarization state in the EDFL. The dual-wavelength soliton laser has a pump threshold of 50 mW at 976 nm, pulse energy of up to 3.4 nJ, peak power of about 2.62 kW, and pulse duration of about 1.3 ps. Additionally, we also demonstrate switchable operation of single-wavelength soliton pulse located at 1531.5 and 1557.5 nm, respectively. Our finding unambiguously implies that apart from its fantastic electric and thermal property, h-BN nanosheets may also possess attractive optoelectronic property for nonlinear photonics, such as mode-locker, Q-switcher, optical limiter and so on.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-01-10
Abstract:Spongy graphene paper with inside foldable corrugated structure is fabricated by electrothermal reduction of the oxygen-containing groups inside RGO paper. Reversible macroscopical length contraction of the spongy graphene paper with strain of 2.4% under 10V voltage is exhibited, mostly attributed to the deformation of corrugated structures.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-01-10
Abstract:Bimorph actuators, consisting of two layers with asymmetric expansion and generating bending displacement, have been widely researched. Their actuation performances greatly rely on the differences of coefficient of thermal expansion (CTE) between the two material layers. Here, by introducing a spongy graphene (sG) paper with large negative CTE as well as highly electrical-to-thermal property, an electromechanical sG/PDMS bimorph actuator is designed and fabricated, showing ultra-large bending displacement output under the low voltage stimulation (curvature of about 1.2cm-1 under 10V voltage for 3s), high displacement-to-length ratio (~0.79), and vibration motion under AC voltage (up to 10Hz), which is much larger and faster than that of the other electromechanical bimorph actuators. Based on the sG/PDMS bimorph serving as the “finger”, a mechanical gripper is constructed to realize the fast manipulation of the objects under 0.1 Hz square wave voltage stimulation (0~8V). The designed bimorph actuator coupled with ultra-large bending displacement, low driven voltage, and ease fabrication, may open up substantial possibilities for the utilization of the electromechanical actuator in practical biomimetic device applications.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-01-10
Abstract:采用低温 AlN 成核层在 Si(111)衬底上用金属有机化学气相沉积(MOCVD)设备摘要:采用低温 AlN 成核层在 Si(111)衬底上用金属有机化学气相沉积(MOCVD)设备生长了 GaN 薄膜。采用高分辨 X 射线衍射、椭圆偏振光谱仪和原子力显微镜研究了 AlN成核层的厚度对 GaN 外延层的影响。对 AlN 的测试表明,AlN 的表面粗糙度随着厚度增加而变大。对 GaN 的测试表明,所有 GaN 样品在垂直方向处于压应变状态,并且随 AlN 厚度增加而略有减弱。GaN 的(0002) ω扫描的峰值半宽(FWHM)随着 AlN 成核层厚度增加而略有升高,GaN(10-12) ω扫描的峰值半宽随着厚度增加而有所下降。(10-12) ω扫描的峰值半宽与 GaN 的刃型穿透位错密度相关。说明 AlN 成核层的厚度较大时,会降低刃型穿透位错密度,并减弱 c 轴方向的压应变状态。
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2017-01-10
Abstract:摘要:在 Si(111)衬底上用金属有机化学气相沉积(MOCVD)设备生长了 AlN 和GaN 薄膜。采用高分辨 X 射线衍射、椭圆偏振光谱仪和原子力显微镜研究了AlN 缓冲层生长时的载气(H2)流量变化对 GaN 外延层的影响。椭圆偏振仪测试表明,相同生长时间内 AlN 的厚度随着 H2流量的增加而增加,即 H2流量增加会导致 AlN 的生长速率提高。原子力显微镜测试表明,随着 H2 流量的增加,AlN 表面粗糙度也呈上升趋势。对 GaN 的测试表明,随着 AlN 生长时的 H2流量增加,GaN 的(0002)和(10-12)的峰值半宽增加,即螺型穿透位错密度和刃型穿透位错密度增加。可能是由于 AlN 缓冲层厚度较大,导致 GaN 的晶体质量有所下降。实验表明,采用较低的 H2 流量生长 AlN 缓冲层可以控制 AlN 的生长速率,在一定程度上有助于提高 GaN 的晶体质量。
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2016-12-23
Abstract:A novel double gate AlGaN/GaN HEMT, in which an additional top-gate covers the adjacent regions of normal gate, was proposed and fabricated for the first time to compare the dynamic characteristics of AlGaN/GaN HEMTs with source field plate(SFP) and gate field plate(GFP). During the dynamic characterization, the device was configured in two operation modes, one is the source-field-plate mode (SFP-mode) with the top gate biased at 0V, another is the gate-field-plate mode (GFP-mode) with applying the gate pulse signal on the top gate at the same time. Compared to an AlGaN/GaN HEMT without field plates, both GFP and SFP much improve the dynamic performances. Compared to SFP, the GFP shows better dynamic performances with a ~34% reduction of switch-on delay time and ~6% reduction of dynamic on-resistance. By study of the dynamic characteristics with applying negative voltage on the top gate during off-state, the mechanism differences between GFP and SFP are discussed in detail.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2016-12-23
Abstract:AlGaN/GaN HEMT适合应用于高压大功率器件,但在高电压动态使用时,存在导通电阻增加的现象[1,2]。目前可以有效降低动态导通电阻的方法有:场板结构[3,4]和AlN介质层[5]等。本论文采用叠层双栅结构AlGaN/GaN HEMT器件,该器件在栅电极之上新增加了一个通过介质层(Si3N4)与栅电极相隔离并可以单独加信号控制的顶栅。在动态下工作时,顶栅电极的脉冲输入信号与栅电极的脉冲输入信号同步。在器件关态时,顶栅电极加0V偏置;在器件开态时,顶栅电极加正电压。顶栅在器件开态下所加正电压越大,器件的动态导通电阻越小。
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2016-12-22
Abstract:This paper presents a fabrication technology of enhancement-mode (E-mode) AlGaN/GaN metal insulator semiconductor high electron-mobility transistors (MIS-HEMTs) using 10 keV fluorine ion implantation. An 8 nm low pressure chemical vapor deposition (LPCVD) silicon nitride layer was deposited on the AlGaN as gate dielectric and energy-absorbing layer that slows down the high energy (10 keV) fluorine ions to reduce the implantation damage. The E-mode MIS-HEMTs exhibit a threshold voltage as high as 3.3 V with a maximum drain current over 200 mA/mm (250 mA/mm for depletion-mode (D-mode) MIS-HEMTs) and a high on/off current ratio of 109. Meanwhile, the E-mode MIS-HEMTs dynamic RON is only 1.53 times than the static RON after off-state VDS stress of 500 V.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2016-12-22
Abstract:An AlGaN/GaN metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs) on Si substrates was obtained with 18 nm Si3N4 grown by low pressure chemical vapor deposition (LPCVD) as gate insulator, The MIS-HEMTs show high Idss of 16.8 A@Vg=3 V, high breakdown voltage of 600 V and a low specific on-resistance of 2.3. The power device figure of merit V2BV/Ron=157MW·cm-2. Furthermore, the good insulation effects of LPCVD-Si3N4 were also demonstrated by the low gate leakage current of below Ig=154 nA@Vds=600 V and Vgs=-14 V. The high Idss, low specific on-resistance and high breakdown voltage show the potential and advantages of GaN MIS-HEMTs for power switching applications.
Peer Review Status:Awaiting Review
Subjects: Materials Science >> Nanoscience and Nanotechnology submitted time 2016-12-22
Abstract:以 AlGaN/GaN HEMT为代表的 GaN基功率晶体管由于具有宽带隙、高工作结温、高摘要:以 AlGaN/GaN HEMT为代表的 GaN基功率晶体管由于具有宽带隙、高工作结温、高击穿场强和高电子迁移率等优点,成为当前功率器件研究的热点。当 GaN 基功率晶体管应用到大功率开关电路中时,为了电路的设计简单和安全方面考虑,一般要求开关器件具有常关特性即需要器件为增强型器件。通过 Ar离子注入实现具有工艺简单、重复性好、稳定可控的优点。本实验通过调整 Ar 离子注入能量、剂量来研究 Ar 离子注入能否实现增强型HEMT器件,同时研究了 LP-SiNx作为能量阻挡层的效果。实验发现 Ar离子注入能实现增强型,但存在着饱和电流小的问题,退火能够修复损伤,一定程度上提高饱和电流。而采用LP-SiNx作为能量阻挡层,可以减小损伤,饱和电流相对提高,但存在着回滞的问题。作为增强型实现方法,Ar离子注入尚需进一步研究并改进。
Peer Review Status:Awaiting Review