Advanced Materials Technologies
·
2024
·Vol. 9
·期 13
·2400073
·
IF 6.4
Yongcheng He,Haojun Liu,Jiajia Luo,Nuo Li,Zhishen Zhang,Jiulin Gan,Zhongmin Yang
Liquid crystal elastomer (LCE) photoactuators offer a versatile platform for executing complicated tasks through precisely controlled bending directions and amplitudes. Optical waveguides assist photoactuators to perform tasks unimpededly. While most existing optical waveguide actuators are limited to unidirectional bending, limiting their versatility. Here, a LCE actuator integrated with a tapered optical fiber with controllable bending directions and amplitudes is presented. The LCE actuator displays bending motions induced by uneven shrinkage due to the off-center fiber. The bending directions are parallel to the previous uniaxial alignment of the LCE film, which can be adjusted to an arbitrary angle with the tapered optical fiber. The LCE actuators exhibit adaptable bending directions at 0°, 45°, and 90°, representing the possible bending motions. The bending amplitudes are regulated by infrared laser power. A hook-like LCE actuator with 0° bending direction carried the handle of a basket. In addition, a 90° bending direction LCE actuator displays the shrinkage behavior, showing a special bending motion control. Moreover, a bionic hand, comprising five LCE actuators with various bending directions, exhibited diverse gestures with precise control. The controllable bending motions in optical waveguide actuators expand the promising applications in complicated scenarios, such as catheters or other medical devices.
研究领域:
材料科学
·
光学工程
·
仿生学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Weide Wang,Dongxu Yao,Hanqin Liang,Yongfeng Xia,Kaihui Zuo,Jinwei Yin,Yu-Ping Zeng
The effect of the GdH 2 on the shrinkage behavior, microstructure, thermal conductivity , and flexural strength was investigated. The pre-sintering enables the elimination of native SiO 2 and the simultaneous formation of Gd 2 O 3 . The N/O ratio in the liquid phase was increased because of the increasing Gd 2 O 3 /SiO 2 ratio, resulting in the restricted shrinkage during gas pressure sintering. The high N/O ratio in the liquid phase benefits not only the nucleation and growth of β-Si 3 N 4 but also the removal of lattice oxygen, leading to the increase of thermal conductivity . Although the replacement of Gd 2 O 3 by GdH 2 leads to enhanced flexural strength at low temperature, it tends to reduce the flexural strength at high temperature. This variation related largely to the exaggerated bimodal microstructure. This work signifies that GdH 2 is an effective sintering additive for obtaining Si 3 N 4 ceramics with both high flexural strength and high thermal conductivity.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yun Liu,Ruixiang Liu,Yuanhang Zheng,Jixue Zhao,Tianyi Sui,Xiaolei Li,Bin Lin
To investigate the mechanism of the influence of the sintering additive ratio on the microstructure evolution of silicon nitride (Si 3 N 4 ) ceramics, Si 3 N 4 ceramics were prepared by gas pressure sintering using different ratios of Y 2 O 3 /MgSiN 2 as additives. Varying the ratio of Y 2 O 3 /MgSiN 2 changed the composition of the liquid phase, thereby affecting the densification process and phase transformation rate of Si 3 N 4 ceramics, and ultimately changing their microstructure. The reduction in the Y 2 O 3 /MgSiN 2 ratio raised the N/O and Si/O ratios in the system, which increased the liquid phase viscosity. The Si 3 N 4 grain distribution varied from "normal to bimodal". In the case of increasing the proportion of MgSiN 2 and prolonging the sintering time, more of the glass phase evaporated, which reduced the content of the low thermal conductivity phase and increased the continuity of Si 3 N 4 /Si 3 N 4 . Therefore, Si 3 N 4 ceramics with 1 wt% Y 2 O 3 and 5 wt% MgSiN 2 exhibited excellent properties after sintering at 1900 °C for 12 h, with thermal conductivity, bending strength , and fracture toughness of 106.7 Wm −1 K −1 , 776 MPa, and 11.66 MPa m 1/2 , respectively.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Manufacturing Processes
·
2024
·
IF 6.1
Lingrong Xing,Mengya Cui,Zheng Zhou,Rongshi Xiao,Ting Huang
A bendable electrode is an essential component of flexible electronics. The resistance stability against deformation is highly desired for practice. In this work, a bendable Cu electrode is fabricated by femtosecond laser direct writing (FsLDW), involving photothermal reduction of Cu ions and deposition of Cu on polyethylene terephthalate (PET) substrate. A highly conductive Cu electrode with a sheet resistance of 0.56 Ω·sq −1 is obtained, which is improved by at least one order of magnitude over previous works. It is worth noting that the sheet resistance of the Cu electrode almost remains unchanged after 6000 downward bending cycles at a bending angle of 30° and shows a slight increase after 10 adhesion tests , demonstrating excellent bending stability and adhesive strength . The porous morphology of the deposited Cu may relieve bending stress, resulting in high deformation resistance . The temperature field simulation confirms sufficient heat accumulation during FsLDW for Cu ion reduction and PET surface melting, allowing for Cu embedding on the PET surface and improving adhesion between the Cu electrode and the substrate.
研究领域:
柔性电子学
·
材料科学
·
激光微加工
✓ 已验证
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2024
·
IF 1.8
Dian Zhang,Xuan Liu,Yijun Liu
Conventional aluminum nitride (AlN) ceramics exhibited insufficient mechanical properties expected from their potential applications in the presence of dynamic loads and intensive stresses caused by thermal shock. In this study, the mechanical properties of AlN ceramics were enhanced by toughening them using AlN whiskers (AlN w ) via gel casting followed by low-temperature sintering at 1650°C. The addition of AlN w simultaneously increased the bending strength, toughness and thermal conductivity of the AlN ceramics. The maximum values of the bending strength, toughness, and thermal conductivity of 9.0 wt% AlN w /AlN were 303.92 MPa, 3.92 MPa·m 1/2 and 186.53 W·m −1 ·K −1 , respectively, which were higher than those of the AlN ceramics by 39.93%, 61.31% and, 15.61%, respectively. The AlN w in AlN w /AlN ceramics tightly bonded with the ceramic matrix, leading to two characteristic toughening mechanisms in the ceramics: crack pinning and deflection at irregular grain boundaries caused by doped whiskers, as well as bridging and stress relaxation caused by whiskers incorporated with the grains. Moreover, the one-dimensional morphology of AlN w can provide a channel for quick photon transport, thereby enhancing the thermal conductivity of AlN w /AlN.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Zhouxi Tan,Mingkang Zhang,Shuai Zhao,Yihua Huang,Zhengren Huang
Low strength and poor performance of SiC–WC composite for seals, attributable to the use of a large amount of liquid phase sintering additives, limit the application prospects of these materials. This study focuses on preparing high-strength, high-toughness, and wear-resistant SiC–WC composite using a small amount of aluminum and carbon black as sintering additives. The results revealed that the specimen containing 50 wt% WC exhibited the maximum flexural strength and fracture toughness of 645.9 MPa and 7.49 Mpa m 1/2 , respectively. These improvements were attributed to the deoxidizing and solid-solution effects of Al and the reinforcing effect of the WC second phase. Moreover, the specific wear rate was measured at 8.06 × 10 −7 mm 3 N −1 m −1 , which was 56.9 % lower than that of monolithic SiC. Results from Raman spectral analysis provided evidence of the presence of W–O bonds on the wear surface, indicating that the SiO 2 film could be successfully replaced by a WO 3 film.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Liang Wang,Wei-Ming Guo,Peng-Fei Sheng,Li-Fu Lin,Xiao Zong,Shang-Hua Wu
A new type of non-oxide sintering additive of YH 2 was introduced for the fabrication of AlN ceramics with high thermal conductivity and flexural strength . The effects of YH 2 addition (0–5 wt%) on the phase composition, densification, microstructure, thermal conductivity and flexural strength of pressureless sintered AlN ceramics were investigated and compared with those Y 2 O 3 -added samples (1–5 wt%). The addition of 1 wt% YH 2 led to an in-situ reduction reaction with oxygen impurities, the formation of Y 2 O 3 and finally the formation of yttrium aluminate, which in turn improved densification and microstructure. A high flexural strength (408.69 ± 28.23 MPa) was achieved. The addition of 3 wt% YH 2 increased the average grain size and purified the lattice. All these effects are believed to help achieve a high thermal conductivity of 184.82 ± 1.75 W·m −1 ·K −1 . Although the thermal conductivity was close to the value of 3 wt% Y 2 O 3 -added sample, its strength was much increased to 381.53 ± 43.41 MPa. Meanwhile, it demonstrated a good combination of the thermal conductivity and flexural strength than the values reported in some literature. However, further increasing the YH 2 addition to 5 wt% resulted in a high N/O ratio that inhibited the densification behavior of AlN ceramics. The current study showed that AlN ceramics with excellent thermal and mechanical properties could be obtained by the introduction of a suitable YH 2 additive.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Tao Feng,Wanbo Hou,Mingde Tong,Hejun Li,Hongjiao Lin,Shifeng Wen
SiC nanowires (SiC nws ) modified SiC f /HfC-SiC composites were prepared by precursor infiltration and pyrolysis (PIP) and chemical vapor infiltration (CVI) methods. The microstructure, flexural strengths, impact and impact-ablation tests of the composites with and without SiC nws were investigated. The results showed that after introducing SiC nws , not only the retention rate of HfC ceramic produced by PIP was increased obviously, but also the fracture displacement of the modified composites was reduced due to the enhancement effect of SiC nws at interface between SiC fiber and matrix. After impact and impact-ablation, the strength retention of SiC nws modified composites was 91.6 % and 69.1 % respectively, higher than that of the composites without SiC nws (85.2 % and 54.8 %). As the impact resistance of the modified composites was improved by the pull-out and bridging of SiC nws , the ablation resistance of the impacted composites was enhanced as well.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Ning Sun,Tengpeng Wang,Yuhang Du,Xiaojun Ma,Wenkai Xin,Haochen Dang,Xuqiu Xie,Tao Wei,Qinggang Li
Si 3 N 4 ceramics pose a challenge when it comes to the preparation of light-curing pastes with high depth of cure, elevated solid content, and low viscosity. This challenge is primarily attributed to their inherent characteristics, including high absorbance, a high refractive index, and suboptimal sphericity. Consequently, the application of Si 3 N 4 ceramics in 3D printing remains a complex endeavor. To address the intricacies associated with 3D printing using Si 3 N 4 ceramics, our research focuses on the utilization of Tetramethylammonium Hydroxide (TMAH) for pH adjustment in Si 3 N 4 ceramics. This adjustment aims to enhance the stability, curing depth, and viscosity of the slurry. Subsequently, we employ this Si 3 N 4 light-curing slurry for 3D printing, followed by sintering the printed materials. The evaluation includes testing for porosity, density, and flexural strength of the samples. Notably, our efforts yield porous silicon nitride ceramics boasting an impressive density of 1.8299 g/cm 3 , porosity measuring 43.718%, and remarkable flexural strength amounting to 275 MPa.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 24
·6416-6422
·
IF 5.976
Taoping Wang,Mingtong Li,Hui Zhang,Yunyu Sun,Bin Dong
Smart actuators have recently been widely studied due to their potential applications in the fields of wearable devices, artificial muscles and microrobots. However, it is still challenging to develop smart actuators with a fast response time, large deformation, multi-stimuli response ability and programmable shape-changing capability. Here, we report a novel smart actuator, which consists of polypyrrole and agar. Due to the water absorbing ability, the photothermal effect and the protonation behavior originating from polypyrrole and agar, the resulting actuator is responsive to a variety of stimuli, including humidity, light, temperature, HCl and NH3 gas. In addition, the actuator exhibits fast responsiveness, controllable actuation and large bending. Interestingly, two external stimuli can be combined to activate the actuator, leading to continuous shape changes in a programmable fashion. Multi-stimuli responsive actuators have opened up great opportunities in a variety of applications. As a proof-of-concept, we have demonstrated their application as a walking device with cargo transportation and delivery capabilities.
研究领域:
材料科学
·
仿生学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF FOOD SCIENCE
·
2020
·Vol. 85
·期 1
·157-164
·
IF 2.479
Hwan Hee Yu,Ye Ji Song,Hyung-Seok Yu,Na-Kyoung Lee,Hyun-Dong Paik
Campylobacter species are known as biofilm-forming bacteria in food systems. The aim of this study was to evaluate the antimicrobial and antibiofilm effects of cinnamaldehyde against Campylobacter jejuni and Campylobacter coli isolated from chicken meat. The biofilm-forming C. jejuni and C. coli strains from chicken meat were investigated using minimum inhibitory concentration (MIC) and Campylobacter spp. characteristics. The MIC value was 31.25 µg/mL for the Campylobacter strains tested. Cinnamaldehyde had an inhibition and degradation effect on Campylobacter biofilms at concentrations > 15.63 µg/mL. Campylobacter strains treated with 15.63 µg/mL CA exhibited significantly decreased autoaggregation, motility, exopolysaccharide production, and soluble protein. In addition, Campylobacter biofilms formed on stainless steel were degraded following cinnamaldehyde treatment, as determined by scanning electron microscopy. Taken together, these results suggest that cinnamaldehyde constitutes a potential natural preservative against Campylobacter and a nontoxic biofilm remover that could be applied to control food poisoning in the poultry manufacturing-related food industry. Practical Application Cinnamaldehyde was able to effectively remove the biofilm of Campylobacter in the small crack of stainless steel. Cinnamaldehyde has a potential to replace the synthetic antimicrobial and/or antibiofilm agent as well as has a positive influence on consumer concern for the food safety issues of the poultry industries.
研究领域:
微生物学
·
食品安全
·
食品科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CERAMICS INTERNATIONAL
·
2013
·
IF 1.789
Chao Jiang,Dou Zhang,Xueping Gan,Rui Xie,Fuqiang Zhang,Kechao Zhou
A new processing technique was proposed for preparing aluminum nitride (AlN)/Hydantion interpenetrating network composites. The technique comprised gelcasting AlN green bodies, degreasing, and infiltrating Hydantion epoxy resin and hardener into the AlN skeleton under a vacuum condition. The effects of AlN contents on the viscosities of AlN slurries and the flexural strength , thermal conductivity , dielectric constant of the AlN/Hydantion composites were evaluated. The highest thermal conductivity and flexural strength of the AlN/Hydantion composites reached 3.56 W/mK and 101.3 MPa, respectively. The fracture surface of the composite revealed that an interpenetrating polymer network in the AlN ceramic skeleton was formed. The AlN/Hydantion composite exhibited the dielectric constant of 7.3 at 1 MHz.
研究领域:
材料科学
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）