Chinese Physics B
·
2024
·
IF 1.5
Shiyue He,Ruoshui Liu,Xujie Liu,Xianping Ye,Lichen Wang,Baogen Shen
Saturation magnetization, magneto-crystalline anisotropy field and dielectric properties are closely related to microwave devices applied at different frequencies. For regulating the magnetic and dielectric properties of W-type barium ferrites, single-phase BaMe2Fe16O27 (Me = Fe, Mn, Zn, Ni, Co) with different Me ions were synthesized by the high-temperature solid-state method. The saturation magnetization (Ms) range from 47.77 emu/g to 95.34 emu/g and the magnetic anisotropy field (Ha) range from 10700.60 Oe to 13739.57 Oe, depending on the type of cation substitution in the hexagonal lattice. The dielectric permittivity and dielectric loss decrease with increasing frequency of the AC electric field in the low-frequency region, while they almost remain constant in the high-frequency region. The characteristics of easy regulation and preparation make it a potential candidate for use in microwave device applications.
研究领域:
材料科学
·
磁学
·
电子学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Run Zheng,Baolong Wang,Kai Shi,Di Sha,Xiangling Ji
The emulsion separation of oily wastewater is always a challenge topic in both fundamental research and practical application. In this paper, polyvinyl alcohol formaldehyde composite sponges (PVF/PVF) with hierarchical pore structure were established by physical absorption/chemical crosslinking and hydrophobic modification via introducing hydrophobic long alkyl chain. As a result, pore size was adjusted from 74.8 µm of pristine PVF to less than 20 µm of hydrophobic PVF, the water contact angle was 120° for final as-prepared sponges, i.e. size sieving and surface wettability could meet the need of emulsion separation. As-prepared sponges could separate W/O (water-in-oil) emulsion efficiently only under the action of gravity, with a maximum flux of 2.9 × 10 5 L m -2 h −1 bar −1 and separation efficiency nearly 100 %. More importantly, the as-prepared sponges displayed excellent reusability, which could be recovered by simply washing. These composite sponges, which were obtained by a simple method and low cost, could be easily scaled up in practical production process, providing an outstanding candidate material for efficient W/O emulsion separation.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2024
·
IF 12.7
Junjie Xu,Wei Sun,Xiang Xiong,Hongbo Zhang
Compared with the traditional C/C composites modified by ultra-high-temperature ceramics (C/C-UHTCs), those modified by metal/medium-entropy ceramics have excellent mechanical properties, thermophysical properties, and long-term ablation resistance. These composites have great potential towards improving the high-temperature resistance and service life of thermal protection systems for spacecraft. In this study, a new type of (Hf 0.5 Zr 0.3 Ti 0.2 )C–W–Cu cermet-modified C/C composites (C/C-(Hf 0.5 Zr 0.3 Ti 0.2 )C–W–Cu) was prepared at 1500 °C. Compared with C/C-UHTCs, the bending strength and fracture toughness of C/C-(Hf 0.5 Zr 0.3 Ti 0.2 )C–W–Cu increased by 70 % and 110 % to 364.25 MPa and 14.64 MPa m 1/2 , respectively. Due to the high thermal conductivity of Cu and W, the thermal conductivity of this new composite was 106 % higher than that of C/C-(Hf 0.5 Zr 0.3 Ti 0.2 )C (44.26 versus 21.53 W/m·K). Under a high heat flow of 4.18 MW/m 2 , this material exhibited very low mass and linear ablation rates (−0.163 mg/s and −0.193 μm/s, respectively). Active and passive protection occur during ablation due to the evaporative cooling of Cu, CuO, and WO 3 as well as a dense outer oxide layer that inhibits oxygen diffusion. The internal oxide layer forms a Hf-Zr-Ti-C-O framework mingled with Ti-rich Ti-Hf-Zr-C-O and an unoxidised W–Cu structure, effectively reducing the osmotic oxygen content. This work provides a new direction for developing thermal protection materials capable of long-term service in ultra-high-temperature environments.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2020
·Vol. 16
·期 48
·2005184
·
IF 11.459
Yong-Ke Li,Geng Zhang,He Huang,Wang-Ting Lu,Fei-Fei Cao,Zhi-Gang Shao
The development of efficient and stable noble-metal-free electrocatalysts for hydrogen evolution reaction (HER) in alkaline media is still a challenge. Herein, a hybrid material formed by the interconnection of Ni 17 W 3 intermetallic compound with metallic W is demonstrated for HER. The Ni 17 W 3 –W hybrid is prepared by the atmosphere- and thermal-induced phase-separation strategy from a single-phase precursor (NiWO 4 ), which gives Ni 17 W 3 –W hybrid abundant and tight interfaces. The theoretical calculation manifests that Ni 17 W 3 shows more optimized energetics for adsorbed H atom, while W has lower energy barrier for water dissociation, and the synergistic effect between them is believed to facilitate the HER kinetics. Moreover, Ni 17 W 3 presents a proper adsorption strength for both adsorbed OH and H, and thus Ni 17 W 3 may also act as a high HER catalyst by itself. As a result, the Ni 17 W 3 –W hybrid demonstrates high activity and durability for HER in liquid alkaline electrolyte; the electrolyzer assembled by Ni 17 W 3 –W hybrid and Ni–Fe-layered double hydroxide (LDH) as, respectively, the cathode and anode electrocatalysts presents superior performance to Pt/C–IrO 2 benchmark. In addition, the Ni 17 W 3 –W hybrid also works well in the water electrolyzer based on solid hydroxide exchange membrane. The present work provides a promising pathway to the design of high-performance electrocatalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2024
·
IF 3.9
Rui Sun,Hongtao Li,Yudan Zhang,Junyi Hua,Wenxin Xu,Kexin Li,Huiqin Guo,Liushui Yan,Shenglian Luo
In this paper, BiOBr@H 3 PW 12 O 40 @BiOI heterostructure with honeycomb-like morphology is successfully constructed for the first time by a simple one-step solvothermal strategy. The introduction of H 3 PW 12 O 40 effectively improves the specific surface area and photon trapping ability of BiOBr@BiOI heterostructure. More importantly, the W 5d electron orbital of H 3 PW 12 O 40 , as an electron bridge, effectively improves the transmission efficiency of photogenerated electrons in the BiOBr@BiOI heterostructure, thus making the BiOBr@H 3 PW 12 O 40 @BiOI heterostructure show excellent performance in the photocatalytic oxidation or reduction reaction. Based on the macro-thermodynamic model proposed in our previous work and the active species capture experiments, the photocatalytic oxidation or reduction mechanism by using as-prepared BiOBr@H 3 PW 12 O 40 @BiOI heterostructure is discussed in detail.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Junjie Xu,Wei Sun,Xiang Xiong,Hongbo Zhang,Lingkun Yang
Spacecraft thermal protection materials need to survive long-term exposure to oxygen-containing environments at 2400 °C. In this study, a high-density and low-porosity metal-ceramic-modified composite was prepared at a low temperature (1500 °C) in the presence of W and Cu using combined slurry brushing and reactive melt infiltration methods. An investigation of the composite formation mechanism and the effects of W and Cu indicated that W and ZrB 2 were formed via dissolution-precipitation and the external diffusion of C and B, respectively. The low reaction temperature and the metallic phases significantly improved the mechanical properties, thermophysical properties, and long-term ablation behaviours of C/C–ZrC–ZrB 2 –W–Cu. Compared to traditional C/C–ZrC, the flexural strength and fracture toughness of the composite increased by 71.56 % and 90.05 % to 345.95 MPa and 14.52 MPa m 1/2 , respectively, and the thermal conductivity increased by 174.93 % to 59.11 W/m·K. In addition, W and Cu effectively lowered the surface temperature by nearly 250 °C during 300 s ablation, and the mass and line ablation rates decreased to −0.272 mg/s and −0.247 μm/s, respectively.
研究领域:
材料科学
·
航天工程
✓ 已验证
产品关联
DOI
高影响因子
POWDER METALLURGY
·
2020
·
IF 1.793
Dongxue Liu,Qiqi Zhang,Longchao Zhuo,Yiheng Zhang,Yanlin Wang,Jintao Xu
In this paper, a combined processing method of mechanical alloying and infiltration was used to prepare the WCu-x wt-%SiC (x = 0.5, 1, 2, 3) composites. The microstructure, density, electrical conductivity and compressive behaviour of the composites were studied comparatively. First a decreasing and then an increasing particle growth trend was obtained, indicating that a small content of SiC below 1 wt-% was beneficial for particle refinement. Besides this, with the increase of the SiC content, both the density and electrical conductivity decreased gradually. Consistent with the particle–particle contiguity of the highest value of 0.404, the WCu-1 wt-%SiC composite showed the best compressive properties. Further electron backscattering diffraction results revealed that the ultrafine-grained SiC particles, which are distributed homogeneously in the composite with lower Schmid factor values would perturb the dislocation motion to make proliferation of more dislocations, exhibiting unordinary strain-hardening during deformation.
研究领域:
材料科学
·
金属学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2020
·
IF 5.162
Lei Wang,Yujie Li,Dong Xiang,Weimin Zhang,Xinpeng Bai
Lutein is a hydrophobic carotenoid with diverse bioactivities. For encapsulating the molecule in a novel method, we prepared two emulsions from xanthan and propylene glycol alginate at the ratios of 3:7 and 4:6. The instability index and particle size of the emulsions were determined using a stability analyzer and laser particle size analyzer. The influence of crystallization on the emulsions was observed under a polarizing microscope. The effects of centrifugal force and storage on the lutein emulsions were analyzed by measuring the changes in absorbance. The results showed that the emulsion fabricated by xanthan and propylene glycol alginate at the ratio of 4:6 was highly stable, and crystals were dispersed when xanthan and propylene glycol alginate existed. These results revealed that the hydrophobicity and absorption kinetics of emulsifiers would determine the stability of emulsion when the viscosity of emulsifiers reached a certain value, and the stability of emulsions would affect the stability of lutein in the emulsions.
研究领域:
食品科学
·
胶体科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
·
2023
·Vol. 107
·期 11
·3745-3761
·
IF 5
Xu Chenglong,Lin Wenxi,Chen Yunni,Gao Boliang,Zhang Zhibin,Zhu Du
Perylenequinones (PQs) are a class of natural polyketides used as photodynamic therapeutics. Heat stress (HS) is an important environmental factor affecting secondary metabolism of fungi. This study investigated the effects of HS treatment on PQs biosynthesis of Shiraia sp. Slf14(w) and the underlying molecular mechanism. After the optimization of HS treatment conditions, the total PQs amount reached 577 ± 34.56 mg/L, which was 20.89-fold improvement over the control. Also, HS treatment stimulated the formation of intracellular nitric oxide (NO). Genome-wide analysis of Shiraia sp. Slf14(w) revealed iNOSL and cNOSL encoding inducible and constitutive NOS-like proteins (iNOSL and cNOSL), respectively. Cloned iNOSL in Escherichia coli BL21 showed higher nitric oxide synthase (NOS) activity than cNOSL, and the expression level of iNOSL under HS treatment was observably higher than that of cNOSL , suggesting that iNOSL is more responsible for NO production in the HS-treated strain Slf14(w) and may play an important role in regulating PQs biosynthesis. Moreover, the putative biosynthetic gene clusters for PQs and genes encoding iNOSL and nitrate reductase (NR) in the HS-treated strain Slf14(w) were obviously upregulated. PQs biosynthesis and efflux stimulated by HS treatment were significantly inhibited upon the addition of NO scavenger, NOS inhibitor, and NR inhibitor, indicating that HS-induced NO, as a signaling molecule, triggered promoted PQs biosynthesis and efflux. Our results provide an effective strategy for PQs production and contribute to the understanding of heat shock signal transduction studies of other fungi.
Key points
• PQs titer of Shiraia sp. Slf14(w) was significantly enhanced by HS treatment . • HS-induced NO was first reported to participate in PQs biosynthetic regulation . • Novel inducible and constitutive NOS-like proteins (iNOSL and cNOSL) were obtained and their NOS activities were determined .
研究领域:
微生物学
·
分子生物学
·
药理学
·
生物技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF NUCLEAR MATERIALS
·
2021
·
IF 2.936
Gang Yao,Xue-Peng Liu,Zhi-Yuan Zhao,Zhi-Hao Zhao,Lai-Ma Luo,Ji-Gui Cheng,Xiang Zan,Qiu Xu,Yu-Cheng Wu
In this study, W-(Y 0.9 La 0.1 ) 2 O 3 composite powders are fabricated by means of a combination of wet chemical method and spark plasma sintering. We systematically study the sintering and densification behavior of W-(Y 0.9 La 0.1 ) 2 O 3 composite powders at different temperatures and pressures. The results indicate that ultrafine tungsten-based composites with a dispersed distribution of (Y 0.9 La 0.1 ) 2 O 3 particles can be achieved under optimized temperature and pressure conditions. The optimized pressure and sintering temperature for W-(Y 0.9 La 0.1 ) 2 O 3 composites are identified to be 75 MPa and 1600 °C, respectively. In addition, the surface damage behavior of W-(Y 0.9 La 0.1 ) 2 O 3 composites induced by the laser thermal shock and helium ion irradiation are also investigated. It is shown that the presence of holes greatly enlarges the helium retention during helium ion irradiation and promotes the melting caused by local overheating during laser thermal shock. We find that the fine-dispersed distribution of (Y 0.9 La 0.1 ) 2 O 3 particles in the tungsten-based composites can effectively improve the resistance of helium ion irradiation and laser thermal shock. We hope that these findings could provide some guidance and reference for the fabrication of large-sized tungsten-based materials in fusion engineering.
研究领域:
材料科学
·
核聚变工程
·
陶瓷学
·
复合材料
·
辐照损伤
✓ 已验证
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Qiuxiang Yao,Lei He,Duo Ma,Yong Zhang,Dan Zhang,Ming Sun
The naphthalene derivatives in coal tar naphthalene and anthracene oil fractions mostly contain short-chain alkyl groups. The enrichment of PAHs (polycyclic aromatic hydrocarbons, mainly including naphthalene, anthracene, and pyrene) by the dealkylation of PAHs-rich fraction in coal tar was assumed to obtain high-purity PAHs by distillation. Based on this strategy, using 2-methylnaphthalene as the model compound, and the influences of catalysts with different supports (SiO 2 , Al 2 O 3 , ZSM-5, Beta, and HY) and different active metal components (Ni, Co, Mo, and W) prepared by the equivalent-volume impregnation method on the hydro-dealkylation performance of 2-methylnaphthalene under different technological conditions (temperature, H 2 initial pressure and reaction time) were systematically investigated in a pressurized batch reactor. The experimental results show that the conversion rate of 2-methylnaphthalene is 81.23 % and the selectivity of naphthalene is 64.22 % under conditions of 480 °C, 2 MPa, 4 h, and 6 W-HY. Loading 0.8 wt% La on the 6 W-HY catalyst can improve the dispersion of active metal component W on the support, but it does not change the skeleton structure of the support. In addition, one-dimensional diffusion is the most probable reaction mechanism for 2-methylnaphthalene, and the evolution profiles of naphthalene can be reflected by the reaction mechanism with a reaction order of n = 4 using the model fitting method.
研究领域:
化学工程
·
催化
·
石油化学
✓ 已验证
产品关联
DOI
高影响因子
PROGRESS IN NUCLEAR ENERGY
·
2020
·
IF 1.508
Jie Wang,Tengfei Zheng,Yong Gao,Dengwang Wang,Wei Cui,Jiakun Fan,Zhiming You,Jing Zhang,Xin Du,Zhaopeng Qiao,Xudong Wang,Sheng Wang,Zhanglian Xu,Chaohui Wang
Due to the inevitable harmful effects of radiation when conducting reactor repair, the robots made of rigid materials have been developed to replace human engineers. Anti-irradiation reinforcement of electronic components is a key issue for robots operating in a radioactive environment. A pneumatic-actuator soft robot was initially proposed for use in this study, due to the advantages of using fewer electronic components that require shielding from gamma rays . This paper presents a novel gamma ray radiation-resistant deformable material for the manufacture of soft robots. Here, the robot partially made of the silicone/W-based composites has the advantages of flexibility and gamma ray shielding property, which provide a novel solution for the collection of the radioactive objects and the detection of the radioactive environmental parameters, such as the temperature. The gamma ray attenuation and tensile elongation properties of the silicone/W and silicone/W/Bi 2 O 3 composites were evaluated, and the surface morphology and lattice structures of the samples with the best radiation attenuation were investigated and analysed. The gamma ray shielding was experimentally assessed by using a 60 Co radioisotope. The test results demonstrated that the gamma transmittance of the silicone/W-based composite reached 0.64452, which was a decrease of approximately 30.0% when compared to pure silicone.
研究领域:
材料科学
·
核工程
·
机器人学
✓ 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）