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81.
In this work a glass ceramic substrate was processed by focusing a laser beam inside the said material. The crystal phase within the amorphous matrix provides mechanical properties to the glass ceramic substrate in such a way that dots can be patterned inside the fore-mentioned material without producing any cracks. These marks are made up of crystals, the growth of which has been induced by the laser beam. These inner structures can modify the optical, thermal and mechanical properties of the glass ceramic substrate.A Q-switched Nd:YAG laser at its fundamental wavelength of 1064 nm with pulsewidths in the nanosecond range has been used.Morphology, composition, microstructure, mechanical and thermal properties of the processed material are described. 相似文献
82.
ZnO and In2O3 films were prepared by thermal oxidation of vacuum deposited zinc and indium films, respectively onto the glass substrate at 30 C. The fabricated films have been irradiated with 100-MeV Ni7+ ions at different fluences ranging from 5×1011 to 5×1013 ions/cm2. The structural and gas sensing properties of pristine and irradiated films have been discussed. X-ray diffraction (XRD) pattern of pristine and irradiated films reveal that the films are polycrystalline in nature and crystallinity increases after irradiation. In this study, highly porous In2O3 nanorods evolved when being irradiated at a fluence of 5×1013 ions/cm2 while ZnO film shows decrease in number of nanowires. The ammonia sensing performance of the Ni7+ irradiated In2O3 films shows an improvement as compared to its pristine counterpart. 相似文献
83.
Sterilization of implants and other clinical accessories is an integral part of any medical application. Although many materials are used as implants, polyethylene stands unique owing to its versatility. Carbon nanotubes are being used as a filler material to enhance the properties of polyethylene. However, the role of multi walled carbon nanotubes (MWCNTs) as an effective antioxidant and radical scavenger in resisting the deteriorating effects of sterilization is yet to be studied in detail. The present work is aimed to investigate the mechanical properties and oxidation stability of irradiated high density polyethylene (HDPE) reinforced by MWCNTs with various concentrations such as 0.25%, 0.50%, 0.75% and 1.00 wt.%. The composites were exposed to 60Co source in air and irradiated at different dosage level starting from 25 to 100 kGy and then shelf aged for a period of 120 days prior to investigation. The loss in toughness, Young’s modulus and ultimate strength at 100 kGy for 1 wt.% MWCNTs composite were found to be 21.5%, 20.3% and 19.2%, respectively compared to that of unirradiated composite. FTIR and ESR studies confirmed the antioxidant and radical scavenging potentialities of MWCNTs with increased concentration and irradiation dosage. It was found that by the addition of 1 wt.% MWCNTs into virgin HDPE, the oxidation index of the composite at 100 kGy was decreased by 56.2%. It is concluded that the addition of MWCNTs into polyethylene not only limits the loss of mechanical properties but also improves its post irradiation oxidative stability. 相似文献
84.
85.
计及旁路二极管效应的太阳能模组性能评估 总被引:3,自引:1,他引:3
为避免功率失配损失,太阳能模组一般都配置旁路二极管,提供一个能量散逸的途径。基于这种配置提出一种新的太阳能模组性能评估算法。依据实际旁路区段配置建立网络方程,通过牛顿–拉夫逊非线性迭代方法实现拓扑求解,继而获得模组的整体性能。在用制造商标准测试数据验证了该评估算法的有效性后,进一步考察各种阴影场景下的模组整体性能,并给出全局最大功率点(maximal power point,MPP)位置随辐射强度变化时的定性结论。理论分析和仿真结果表明,由于多辐射强度导致功率多峰值的存在,常规最大功率点跟踪(maximal power point track,MPPT)算法可能会因为只能检测到MPPT伪极大值点而失效;而且,旁路二极管的合理配置对太阳能模组性能有很大影响。 相似文献
86.
AbstractA series of SnO2 nanocrystallines decorated g-C3N4 architectures were synthesized using a facile solvothermal method. The structural, morphological, and optical properties of the as-prepared nanocomposites were characterized in detail, indicating that SnO2 nanocrystallines with diameter ~ 4?nm were well-dispersed on the surface of g-C3N4. The photocatalytic activity of the composites was investigated by degrading rhodamine B (RhB) under visible light irradiation. The CNS2 heterostructure exhibits enhanced photocatalytic activity than bare SnO2 and g-C3N4. Kinetic study revealed a promising degradation rate constant of 0.0593?min?1 for the CNS2, which is 118 and 7 times higher than that of pure SnO2 and g-C3N4, respectively. What’s more, the CNS2 still retained the photocatalytic activity after three cycle measurements. The enhanced photocatalytic performances of the nanocomposite may be due to its large surface area (116.2 m2/g), appropriate ratio of SnO2/g-C3N4 and the compact structure of the junction between the SnO2 nanocrystallines and the g-C3N4, which inhibits the recombination of photogenerated electrons and holes. 相似文献
87.
Low‐Energy Electron Beam Induced Charging and Secondary Electron Emission Properties of FEP Film Used on Satellite Surfaces 下载免费PDF全文
Many kinds of insulating materials are used outside a spacecraft. They include FEP films, polyimide films, and so on, and are used as thermal control materials. These materials are exposed to a charged‐particle environment around the spacecraft. Thus then become charged due to charged particles, especially electrons. It has been pointed out that charging of these materials is likely to cause discharges on the surfaces. From this viewpoint, we investigated the charging potential characteristics of 127‐μm‐thick FEP film, a typical thermal control material, by exposing it to electron irradiation at various energies below 20 keV. In the dependence of the charging potential on the electron energy, we found that the electron energy at which no charge‐up occurs is about 2.7 keV. This appears to be the energy at the which secondary electron emission yield becomes unity. This indicates that electron irradiation of FEP film with energies lower than 2.7 keV induces positive charging. From the charge decay characteristics after electron irradiation, the volume resistivity of the film was also obtained as a function of the electric fields in the bulk of the FEP film. 相似文献
88.
《Advanced Powder Technology》2022,33(12):103859
Constructing heterojunction provides a promising tactic to improve the photocatalytic efficiency of catalysts. In this paper, hierarchical FeIn2S4/BiOBr heterostructure photocatalysts were prepared by facile two step methods and applied to effectively remove ciprofloxacin (CIP) and tetracycline (TC) under visible light. Compared to single catalyst, FeIn2S4/BiOBr hybrids display significantly improved photocatalytic activity. Among the series, 6 wt% FeIn2S4/BiOBr shows the optimal photocatalytic performance, where the degradation efficiencies of TC and CIP are 3.15 and 2.88 times greater than pure BiOBr, respectively. Such an improvement could arise from the S-scheme heterojunctions and unique hierarchical structures, which brings stronger light absorption, higher photoexcited charge separation efficiency and superior redox ability. Furthermore, 6 wt% FeIn2S4/BiOBr composite exhibits excellent stability and reusability. Radical capture experiments and EPR analyses uncover that O2–, h+ and OH are primarily reactive substances during photocatalytic removal of TC. The products of TC were detected by LC-MS analyses and possible decomposition paths are proposed. Eventually, a possible photodegradation mechanism over FeIn2S4/BiOBr S-scheme heterojunction is proposed. These findings supply new perspective for the simple synthesis of S-scheme photocatalysts with promising applications in environment remediation. 相似文献
89.
The near tip stress intensity factor KItip for an edge-crack in a Pb(ZrxTi1−x)O3 thin film was investigated by superposition of the applied stress intensity factor KIapp under a continuous laser irradiation and the shielding stress intensity factor ΔKI for 90° domain switching. Both KIapp and ΔKI were solved by the weight function method, and switching toughening was analyzed based on the small scale domain switching theory. Results show that KItip of the edge-crack in the thin film is significantly affected by the initial poling angle, and the edge-crack tip is toughened by the domain switching area with the increase of the initial poling angle. The methodology can predict the fracture toughening of Pb(ZrxTi1−x)O3 thin films quantitatively. 相似文献
90.
We model numerically the mechanical effects of UV induced photo-polymerization in elastomeric artificial lens. The elastomer
is originated upon cross-linking of a silicone matrix. UV irradiation of one side of the lens polymerizes selectively a photosensitive
macromer, causing local variations of its concentration. The subsequent diffusion of macromers from high concentration to
low concentration zones modifies the shape of the lens and thus its dioptric power. In vitro experiments on artificial lens
showed that the power change is dependent on UV exposure time, irradiation intensity and light pattern. With the aim to define
a numerical tool able to predict the dioptric power adjustment as a function of the UV irradiation parameters, we setup a
purely mechanic finite element model of the lens, adopting a hyperelastic material model embedded with eigen-deformations.
Numerical simulations of axis-symmetric irradiation closely reproduced the experimental results, in terms of both lens geometry
and dioptric power, for positive, negative and lock-in corrections. 相似文献