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1.
Nanocrystallized steel surface by micro-shot peening (MSP) were applied to carbon nanotube growth in this study. Micro-shot peening treatment severely deformed steel surface and nanocrystallized surface layer was formed by the plastic deformation. The grain sizes of the nanocrystallized layer were 10-30 nm after 300 s of MSP treatment. On the nanocrystallized surface, carbon nanotubes were formed with thermal chemical vapour deposition without catalysts. Before carbon nanotube growth, the nanocrystallized steel surface was reduced with H2/N2 gas at 600 °C. The carbon nanotube growth was performed at 600 °C with C2H2 gas carried by H2/N2 gas. The carbon nanotubes formed on the nano-structured surface was multi-walled carbon nanotube and the diameter was 10-20 nm. The reduction process before carbon nanotube growth was essential to form carbon nanotubes on the nanocrystallized surface with MSP. 相似文献
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A simple, inexpensive gas phase reaction termed as “nanocarving process” converts TiO2 grains into arrays of single crystal nanofibers by selective and anisotropic etching. This process is conducted by exposing dense polycrystalline TiO2 to a H2/N2 environment at 700 °C. The dimensions of nanofibers are around 20 nm in diameter and 1 μm in length. The preferred crystallographic orientation for the nanocarving process is the <001> direction. Nanoparticles composed of Fe and Ni were observed on the surface of TiO2 that formed nanofiber tips. Sintering parameters before the nanocarving treatment play a critical role in the formation of nanofibers. As sintering temperature and time increased, the rate of nanofiber generation decreased. Moreover, it was observed that by varying the heat treatment conditions, it is possible to create other structures like nanowhiskers and nanofilaments. Nanowhiskers were formed by reoxidation of nanofiber-formed TiO2 over 600 °C. Nano-filaments were generated by heat treating sintered TiO2 in N2-carrying water vapor at 700 °C. 相似文献
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We propose an estimation-theoretic approach to the inference of an incoherent 3D scattering density from 2D scattered speckle field measurements. The object density is derived from the covariance of the speckle field. The inference is performed by a constrained optimization technique inspired by compressive sensing theory. Experimental results demonstrate and verify the performance of our estimates. 相似文献
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Chang S Combs ZA Gupta MK Davis R Tsukruk VV 《ACS applied materials & interfaces》2010,2(11):3333-3339
We demonstrate the in situ growth of silver nanoparticles in porous alumina membranes (PAMs) for use as a surface-enhanced Raman scattering (SERS) detection substrate. This fabrication method is simple, cost-effective, and fast, while providing control over the size of silver nanoparticles through the entire length of the cylindrical nanopores with uniform particle density inside the pores unachievable by the traditional infiltration technique. The in situ growth of silver nanoparticles was conducted from electroless-deposited nanoscale seeds on the interior of the PAM and resulted in the formation of numerous hot spots, which facilitated significantly higher SERS enhancement for these substrates compared with previously reported porous substrates. 相似文献
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Kang IS Lee TY Yoo S Lee CW So HM Ahn CW 《Journal of nanoscience and nanotechnology》2012,12(4):3593-3596
An in-situ electrical conductivity measurement of thin films of tin oxide nanoclusters for nano-devices was performed during metal cluster deposition and subsequent oxidation. From the current observation, the percolation threshold and the oxidation process are suggested. During baking at 200 degrees C, tin nanoclusters were transformed into low-conductivity stannous oxide and then into high-conductivity stannic oxide. From electron micrographs, it is suggested that the baking procedure is responsible for changing the oxide state and/or the crystallinity of the individual nanoclusters rather than changing the morphology of the film. 相似文献
7.
Homogeneous 2D MoTe2 p–n Junctions and CMOS Inverters formed by Atomic‐Layer‐Deposition‐Induced Doping 下载免费PDF全文
June Yeong Lim Atiye Pezeshki Sehoon Oh Jin Sung Kim Young Tack Lee Sanghyuck Yu Do Kyung Hwang Gwan‐Hyoung Lee Hyoung Joon Choi Seongil Im 《Advanced materials (Deerfield Beach, Fla.)》2017,29(30)
Recently, α‐MoTe2, a 2D transition‐metal dichalcogenide (TMD), has shown outstanding properties, aiming at future electronic devices. Such TMD structures without surface dangling bonds make the 2D α‐MoTe2 a more favorable candidate than conventional 3D Si on the scale of a few nanometers. The bandgap of thin α‐MoTe2 appears close to that of Si and is quite smaller than those of other typical TMD semiconductors. Even though there have been a few attempts to control the charge‐carrier polarity of MoTe2, functional devices such as p–n junction or complementary metal–oxide–semiconductor (CMOS) inverters have not been reported. Here, we demonstrate a 2D CMOS inverter and p–n junction diode in a single α‐MoTe2 nanosheet by a straightforward selective doping technique. In a single α‐MoTe2 flake, an initially p‐doped channel is selectively converted to an n‐doped region with high electron mobility of 18 cm2 V?1 s?1 by atomic‐layer‐deposition‐induced H‐doping. The ultrathin CMOS inverter exhibits a high DC voltage gain of 29, an AC gain of 18 at 1 kHz, and a low static power consumption of a few nanowatts. The results show a great potential of α‐MoTe2 for future electronic devices based on 2D semiconducting materials. 相似文献
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Zwicker M. Vetro A. Sehoon Yea Matusik W. Pfister H. Durand F. 《Signal Processing Magazine, IEEE》2007,24(6):88-96
Multiview three-dimensional (3-D) displays offer viewing of high-resolution stereoscopic images from arbitrary positions without glasses. This article surveyed different approaches to develop signal processing algorithms for these displays. Such displays consist of view-dependent pixels that reveal a different color according to the viewing angle. Therefore, the left and right eye of an observer sees slightly different images on the screen. This leads to the perception of 3-D depth and parallax effects when the observer moves. Although the basic optical principles of multiview auto-stereoscopy have been known for over a century, only recently displays with increased resolution, or systems based on multiple projectors, have made this approach practical. 相似文献
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Han Sol Lee Sam Park June Yeong Lim Sanghyuck Yu Jongtae Ahn Do Kyung Hwang Yumin Sim Je‐Ho Lee Maeng‐Je Seong Sehoon Oh Hyoung Joon Choi Seongil Im 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(38)
Band‐like transport behavior of H‐doped transition metal dichalcogenide (TMD) channels in field effect transistors (FET) is studied by conducting low‐temperature electrical measurements, where MoTe2, WSe2, and MoS2 are chosen for channels. Doped with H atoms through atomic layer deposition, those channels show strong n‐type conduction and their mobility increases without losing on‐state current as the measurement temperature decreases. In contrast, the mobility of unintentionally (naturally) doped TMD FETs always drops at low temperatures whether they are p‐ or n‐type. Density functional theory calculations show that H‐doped MoTe2, WSe2, and MoS2 have Fermi levels above conduction band edge. It is thus concluded that the charge transport behavior in H‐doped TMD channels is metallic showing band‐like transport rather than thermal hopping. These results indicate that H‐doped TMD FETs are practically useful even at low‐temperature ranges. 相似文献
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Multifunctional Photonics Nanoparticles for Crossing the Blood–Brain Barrier and Effecting Optically Trackable Brain Theranostics 下载免费PDF全文
Ajay Singh Woong Kim Youngsun Kim Keunsoo Jeong Chi Soo Kang YoungSoo Kim Joonseok Koh Supriya D. Mahajan Paras N. Prasad Sehoon Kim 《Advanced functional materials》2016,26(39):7057-7066
Theranostic photonic nanoparticles (TPNs) that cross the blood–brain barrier (BBB) and efficiently deliver a therapeutic agent to treat brain diseases, simultaneously providing optical tracking of drug delivery and release, are introduced. These TPNs are constructed by physical encapsulation of visible and/or near‐infrared photonic molecules, in an ultrasmall micellar structure (<15 nm). Phytochemical curcumin is employed as a therapeutic as well as visible‐emitting photonic component. In vitro BBB model studies and animal imaging, as well as ex vivo examination, reveal that these TPNs are capable of transmigration across the BBB and subsequent accumulation near the orthotopic xenograft of glioblastoma multiforme (GBM) that is the most common and aggressive brain tumor whose vasculature retains permeability‐resistant properties. The intracranial delivery and release of curcumin can be visualized by imaging fluorescence produced by energy transfer from curcumin as the donor to the near‐infrared emitting dye, coloaded in TPN, where curcumin induced apoptosis of glioma cells. At an extremely low dose of TPN, a significant therapeutic outcome against GBM is demonstrated noninvasively by bioluminescence monitoring of time‐lapse proliferation of luciferase‐expressing U‐87 MG human GBM in the brain. This approach of TPN can be generally applied to a broad range of brain diseases. 相似文献