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991.
GuangGen?ZengEmail author JingQuan?Zhang Bing?Li Wei?Li LiLi?Wu WenWu?Wang LiangHuan?Feng 《中国科学:技术科学(英文版)》2015,58(5):876-880
In this paper, the effects of different CdCl2 annealing methods, including vapor annealing and dip-coating annealing, on the performance of CdS/CdTe polycrystalline thin-film solar cells are studied. After annealing, the samples are lightly etched with 1% bromine in methanol to remove surface oxides. Both annealing methods give CdTe polycrystalline thin films with good crystallinity and complete structure. For solar cells containing the annealed CdTe films, cell efficiency first increases and then decreases as the concentration of CdCl2 solution used for dip-coating annealing increases, and the optimized CdCl2 concentration is 12%. The uniformity of the performance of all cells is analyzed by calculating the relative standard deviation for each parameter. The uniformity of cell performance can be improved dramatically by dip-coating annealing instead of vapor annealing. Most notably, an appropriate concentration of CdCl2 (12%) acts as a protective layer that is conducive to realizing uniform high-performance CdS/CdTe solar cells. According to the location of depletion regions, the CdTe films treated by dip-coating annealing show a relatively low doping concentration, except for the sample treated with a CdCl2 concentration of 6%, which is consistent with the changes of short-circuit current density of the cells. It is believed that these results can be applied to the large-scale production of CdTe polycrystalline thin-film solar cells. 相似文献
992.
Jae-Sang?ParkEmail author Young?Jung?Kee 《Journal of Mechanical Science and Technology》2015,29(8):3153-3163
This paper conducts the aeromechanics study using the two different rotorcraft computational structural dynamics (CSD) codes, CAMRAD II and DYMORE II, for the rotor in low-speed descending flight. The three test cases of the HART (Higher-harmonic control aeroacoustic rotor test) I -baseline, minimum noise, and minimum vibration- are considered in this study of the blade-vortex interaction (BVI) airloads, rotor trim, blade elastic deformations, and blade structural loads. The two prediction results are compared to each other for a code-to-code comparison study as well as to the measured data. Although CAMRAD II and DYMORE II use different theories and models, most of the prediction results are similar to each other and compared fairly well with the wind tunnel test data. For all the three test cases, the two rotorcraft CSD analyses show good prediction on the fluctuations of the section normal force (M2Cn) due to BVI, but both over-predict the trimmed collective pitch angle. The blade elastic deformations, such as flap deflection and elastic torsion deformation at the tip, are reasonably predicted by both rotorcraft CSD analyses. But, the CAMRAD II result using the multiple-trailer wake model with consolidation is slightly better than the DYMORE II prediction with the single wake panel model particularly for the elastic torsion deformation in the baseline case. In addition, CAMRAD II and DYMORE II both correlate reasonably the blade structural loads, such as flap bending, lead-lag bending, and torsion moments, with the measured data; however, the CAMRAD II results are moderately better than the DYMORE II predictions. 相似文献
993.
Nisha Sheth Carl Greenley Raul Bermejo John C. Mauro Carlo G. Pantano Seong H. Kim 《Journal of the American Ceramic Society》2021,104(9):4550-4558
Water or acid soaking surface treatments have been shown to increase the mechanical strength of soda-lime silicate (SLS) glasses. This increase in strength has traditionally been attributed to effects related to residual stress or changes in fracture resistance. In this work, we report experimental data that cannot be explained based on the existing knowledge of glass surface mechanics. In dry environments, annealed and acid-leached SLS surfaces have comparable crack initiation stress and fracture stress as measured by Hertzian indentation and biaxial bending tests, respectively. Yet, in the presence of humidity, acid-leached surfaces have higher failure stress than the annealed surfaces. This apparent enhancement in the crack resistance of the acid-leached surface of SLS glass in humid environments supports the hypothesis that acid-leached surface chemistry can lower the transport kinetics of molecular water to critical flaws. 相似文献
994.
Huy Minh Dao Amit Raviraj Pillai Rishi Thakkar Sanjiv Parajuli Esteban Urena-Benavides Seongbong Jo 《应用聚合物科学杂志》2021,138(2):49665
Light-sensitive drug delivery systems are considered ideal for applications in the biomedical fields for their ability to release the payload in an on-demand spatiotemporal controlled manner through the manipulation of the light source. Among the broad radiation spectrum, near infrared (NIR) light is considered advantageous compared to UV and visible light, due to its inherently lower photodamage to normal tissues and deeper penetration to lesion areas. In this study, we report a successful synthesis of a polymer capable of undergoing partial degradation upon irradiation with NIR light by conjugating 10-N-carbamoyl linkage methylene blue (MB) moiety, a NIR photocleavable ligand, with polyethylene glycol (PEG). Through effective coupling of MB, a hydrophobic moiety, to the hydrophilic PEG molecule, an amphiphilic polymer was synthesized, as demonstrated by a lowered surface tension (55 mN/m at 0.1% wt/vol). Subsequently, photo-induced reversal of surface activity associated with self-assembled structure disruption, was displayed by surface tension measurements, size distribution analysis, and burst release profile of paclitaxel (PTX) from polymeric micelles upon the exposure to NIR irradiation. 相似文献
995.
Jae-Chul?LeeEmail author Jae-Hyeok?Shim Ho-In?Lee 《Metals and Materials International》2003,9(4):369-373
In an ASZ/A384 Al composite, the interfacial reaction was observed to take place between the SiO2 binder layer and Mg within the matrix to form MgAl2O4 at the interface. Formation of MgAl2O4 at the interface between ASZ short fibers and the Al matrix alloy is believed to enhance the interfacial bonding strength,
resulting in improved composite strength. However, the interfacial reaction in the ASZ/A384 Al proceeds at the expense of
Mg in the matrix, resulting in a composite devoid of Mg bearing precipitates such as Al2CuMg and Mg2Si. 相似文献
996.
Weichang Xue Amit Bandyopadhyay Susmita Bose Chuanxian Ding K.M.C. Cheung 《Surface & coatings technology》2007,201(8):4685-4693
The use of strontium-containing hydroxyapatite (Sr-HA) as a biomaterial has been reported recently. In vitro and in vivo studies have shown that Sr-HA promotes osteoblast response and stimulates new bone formation. In order to extend its usage to major load-bearing applications, such as artificial hip replacement, it has been proposed that the material could be used in the form of a coating on implant surfaces. This paper reports a preliminary study of biocompatibility of plasma sprayed Sr-HA coatings on a metallic substrate. Coatings of Sr-HA containing 10 mol% Sr2+ was produced on titanium alloy substrates. The coating exhibited good bonding with the substrate. The bioactivity of Sr-HA coating was evaluated in vitro by immersion in simulated body fluid (SBF). After immersion in SBF, Sr-HA coating exhibited great ability to induce apatite precipitation on its surface. The possible effects of cell-materials interactions of Sr-HA coating were examined by culturing osteoprecursor cells (OPC1) on coating surfaces. The effect of Sr-HA was also compared to a hydroxyapatite (HA) coating, which is widely used in orthopedics and dentistry. The results indicated that Sr-HA coating had good biocompatibility with human osteoblasts. OPC1 cells survived and proliferated well on the surface of coating. Sr-HA coating promoted OPC1 cells attachment, and more local contacts were produced on the surface. The presence of Sr stimulated OPC1 cell differentiation and ALP expression. No deleterious effect on ECM formation and mineralization was found with Sr-HA coating. The results indicated that Sr-HA coating had good mechanical properties and bioactivity in vitro. 相似文献
997.
Chan-Ik?Park Han-Cheol?ChoeEmail author Chae-Heon?Chung 《Metals and Materials International》2004,10(6):549-553
Regardless of the type of performed restoration, in most cases, a screw connection is employed between the abutment and implant.
For this reason, implant screw loosening has remained a problem in restorative practices. The purpose of this study was to
compare the surface of coated/plated screws with titanium and gold alloy screws and to evaluate the physical properties of
coated/plated material after scratch tests via FE-SEM (field emission scanning electron microscopy) investigation. GoldTite,
titanium screws provided by 3i (Implant Innovation, USA) and TorqTite, titanium screws by Steri-Oss (Nobel Biocare, USA) and
gold screws and titanium screws by AVANA (Osstem Implant, Korea) were selected for this study. The surface, crest, and root
of the abutment screws were observed by FE-SEM. A micro-diamond needle was also prepared for the scratch test. Each abutment
screw was fixed, and a scratch on the surface of the head region was made at constant load and thereafter the fine trace was
observed with FE-SEM. The surface of GoldTite was smoother than that of other screws and it also had abundant ductility and
malleability compared with titanium and gold screws. The scratch tests also revealed that teflon particles were exfoliated
easily in the screw coated with teflon. The titanium screw had rough surface and low ductility. The clinical use of gold-plated
screws is recommended as a means of preventing screw loosening. 相似文献
998.
A single stable adatom on a {110}-type plane of a tungsten tip is created via field-evaporation in a field-ion microscope
(FIM) operating at room temperature. This single adatom has sufficient surface mobility at room temperature and migrates,
in one-dimension, along a <111>-type direction toward an edge of a {110}-type plane, due to the existence of an electric field
gradient. The plane edge has a higher local electric field than its center, since it has a higher local geometric curvature.
This result implies that the stable position of a single adatom during a scan of a scanning tunneling microscope (STM) tip
on a surface is at the edge and not at the center of a {110}-type plane at room temperature. Therefore, the electron wave
function of a tip is not symmetric and this fact should be taken into account in a careful analysis of STM images. Also a
tip with a dislocation emerging at a {110}-type plane is suggested as an improved STM tip configuration, as the step at the
surface, created by the intersection of the dislocation with it, is a perpetual source of single adatoms. 相似文献
999.
Solidus temperatures of the B2 NiAl phase have been determined by high-temperature differential thermal analysis for binary
melt compositions NixAl100−x
(45<x<57) and for ternary alloys FeyNi50−yAl50 (0≤y≤50). It was shown that the melting temperature of the stoichiometric Ni50Al50 phase is 1681 °C, which is 43 K higher than some literature data. The solidus line at the Ni-rich side of the Ni-Al phase
diagram exhibits a steeper slope than that reported previously. Substituting Fe for Ni, the decrease of solidus temperature
along the isoplethal section with 50 at.% Al of the ternary Ni-Fe-Al phase diagram exhibits a steep initial slope of −13 K/at.%
Fe for small Fe-fractions, which changes into a nearly linear decrease with an average slope of −8.5 K/at.% Fe. 相似文献
1000.
Poly(N-methylaniline) (PNMA) coatings have been electropolymerized on 304 stainless steel alloy by potentiodynamic, galvanostatic and potentiostatic synthesis techniques from aqueous solutions of 0.1 M N-methylaniline (NMA) and 0.3 M oxalic acid. Characterization of PNMA coatings was carried out by cyclic voltammetry, UV-Vis and FTIR spectroscopy techniques. Corrosion behavior of PNMA coated stainless steel electrodes was investigated using linear anodic potentiodynamic polarization, Tafel test, chronoamperometry and electrochemical impedance spectroscopy (EIS) techniques in 0.5 M aqueous HCl solutions. Corrosion test results showed that PNMA coatings possessed protection to uncoated stainless steel against corrosion. 相似文献