COMBUSTION EXPLOSION AND SHOCK WAVES
·
2014
·Vol. 50
·期 6
·664-669
·
IF 0.486
Ao W.,Zhou J. H.,Yang W. J.,Liu J. Z.,Wang Y.,Cen K. F.
Ignition, combustion, and oxidation characteristics of mixtures of amorphous and crystalline boron powders are studied by using a laser ignition system and a thermogravimetric analyzer. Yellow, green, and white-glow flames are observed. When the weight ratio of the amorphous boron powder ( K ) is lower than 0.33, burning of the mixtures is found to be at the ignition stage, while the combustion stage gradually appears with increasing K . The emission spectrum intensity is weakened by 3/4 as K decreases from 1 to 0.75. No obvious emission spectrum is detected at K < 0.33. The ignition delay time is found to decrease significantly with increasing K , but it does not change much at K < 0.8. Mixtures with larger values of K have a lower peak temperature of differential thermal gravity and a greater weight gain and maximum reaction rate. The Satava-Sestak method is applied to study the kinetics of the oxidation reaction of the mixtures. The calculated apparent activation energy decreases from 297 to 191 kJ/mol as K increases from 0 to 1. For mixtures with K ranging from 0.23 to 0.75, the apparent activation energy mainly stays constant at a value of 280 kJ/mol.
研究领域:
材料科学
·
燃烧与热能工程
✓ 已验证
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-13
·
IF 14.7
Wu Yuhan,Zhao Yuying,Yuan Qixin,Sun Hao,Wang Ao,Sun Kang,Waterhouse Geoffrey I. N.,Wang Ziyun,Wu Jingjie,Jiang Jianchun,Fan Mengmeng
Carbon nanomaterials show outstanding promise as electrocatalysts for hydrogen peroxide (H 2 O 2 ) synthesis via the two-electron oxygen reduction reaction. However, carbon-based electrocatalysts that are capable of generating H 2 O 2 at industrial-level current densities (>300 mA cm −2 ) with high selectivity and long-term stability remain to be discovered. Herein, few-layer boron nanosheets are in-situ introduced into a porous carbon matrix, creating a metal-free electrocatalyst (B n -C) with H 2 O 2 production rates of industrial relevance in neutral or alkaline media. B n -C maintained > 95% Faradaic efficiency during a 140-hour test at 300 mA cm −2 and 0.1 V vs. RHE, and delivered a mass activity of 25.1 mol g catalyst −1 h −1 in 1.0 M Na 2 SO 4 using a flow cell. Theoretical simulations and experimental studies demonstrate that the superior catalytic performance originates from B atoms with adsorbed O atoms in the boron nanosheets. B n -C outperforms all metal-based and metal-free carbon catalysts reported to date for H 2 O 2 synthesis at industrial-level current densities.
研究领域:
材料科学
·
电化学
·
催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
·
2024
·
IF 6.7
Zi-Chun Fan,Zhuang Li,Xiang Bai,Xian-Yong Wei,Yierxiati Dilixiati,Qian-Qian Kong,Ji Zhao,Yong-Hui Feng,Zhi-Min Zong,Jun-Long Wang
The catalytic hydroconversion (CHC) of benzyloxybenzene (BOB) and oxydibenzene (ODB), two typical lignite-related model compounds (LRMCs) representing α-Ο-4 and 4-O-5 model linkages , have been investigated using uniformly dispersed Ni 15 /HY prepared by a three-step method. The cleavage of >CH-O- bridged bonds in BOB and partial hydrogenation of ODB are considered as a crucial first step, and the target reactions in this work are to produce complete hydrodeoxidized ring saturation products. Through the exploration of reaction mechanism, H + /H - and biatomic active hydrogen, as the main hydrogen species involved in the reaction, play an important role in the CHC of BOB and ODB. Herein, the synergic effect between the hydrogenation of nickel nanoparticles and the acidic function of Y -type zeolite improves the CHC performance, resulting in Ni 15 /HY displaying proficient catalytic activity and selectivity for the CHC of BOB and ODB. Under the optimal reaction conditions, BOB and ODB can be completely converted to cyclanes over Ni 15 /HY, and the main products are dicyclohexylmethane (57.6 %) and cyclohexane (92.4 %), respectively. The developed Ni 15 /HY can not only promote the hydroconversion of BOB and ODB to produce ring-saturated products, but also undergo the rearrangement reaction to produce two- or three-ring cyclanes, which is desirable to upgrade LRMCs to high-density hydrocarbon fuels .
研究领域:
化学工程
·
燃料化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
·
2024
·
IF 4.2
Jiandong Hao,Ling Li,Bin Zhang,Ningqiang Shi,Tingwei Yan,Jinchang Meng
We used dry-wet transfer to prepare boron nitride nanoribbons (BNNRs) film. The effects that the different BNNRs film areas by dry transfer, the different areas and thicknesses of BNNRs film by wet transfer on BNNRs deep ultraviolet (DUV) detector were investigated, respectively. There is an excellent capability of detection and sensing for dry transfer DUV detector. The photocurrent rises with the area of the film. The maximum photocurrent ( I phmax ) is 34 pA at 1.64 mW/cm 2 (0.3 × 0.7 cm 2 , 30 mg). Rise and fall time are around 0.38s/0.41s. The responsivity and detectivity are 0.23μA/W and 5.57 × 10 7 (0.41 mW/cm 2 , V bias = 10V). The direct transfer of the MCE filter membrane by wet transfer can control the size and thickness of the film. The I phmax becomes larger with the thickness of the BNNRs film ( I phmax : 171 pA). And the time response is about 0.73s/0.72s, the responsivity and detectivity are up to 0.71μA/W and 1.72 × 10 8 (0.41 mW/cm 2 , V bias = 10V). However, it does not have a better ability to sense the DUV light than dry transfer. Therefore, different transfer methods can be applied to various requirements. This provides a good prospect for the high-performance DUV detectors.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Chong Wan,Suhang Chen,Xinglong Liu,Yushu Xiong,Zhao Qin,Jianbin Li,Fengqi Zhao,Kangzhen Xu
To enhance energy release of boron-based metastable intermixed composites (MICs), a series of B-based MICs were constructed successfully by a facile one-step sol-freeze-drying (SFD) method, where copper oxide (CuO) was employed as oxidant. The structure, morphology, chemical state and specific surface area of B-based MICs were investigated by several characterization technologies, and their reactivity and combustion performance were further studied by various experimental tests. The results reveal that B and CuO nanoparticles are dispersed evenly on a nest network braided by the molecular interaction between polyvinyl pyrrolidone (PVP) and nitrocellulose (NC), and the constant volume combustion heat of B-based MICs even reaches 8956.6 ± 76.6 J·g −1 when PVP (1.25 wt%) and NC (5.0 wt%) were added into B/CuO, respectively. The heat value is about 1.7 times as big as pristine B/CuO (5345.5 ± 36.1 J·g −1 ) and approaches to that of raw B NPs (10335.5 ± 507.8 J·g −1 ). Moreover, the condensed phase residues of three composites were collected and confirmed to be Cu and Cu 2 O, while the smallest particle size distribution of product proves that the combustion of B/CuO/NC(NC: 5.0 wt%, PVP: 1.25 wt%) is most complete. So the unique nest network can eliminate particle aggregation, shorten the transfer distance of mass and heat and improve the “solid − solid” thermite reaction between B and CuO NPs. This work will provide a new strategy for promoting the application of boron.
研究领域:
材料科学
·
燃烧化学
✓ 已验证
产品关联
DOI
高影响因子
ACS ES&T Engineering
·
2024
·
IF 7.4
Yi Shen,Mingzheng Yang,Chao Zhu,Haizhong Zhang,Renlan Liu,Jun Wang,Qile Fang,Shuang Song,Baoliang Chen
The activation of peroxymonosulfate (PMS) to generate singlet oxygen (1O2) for the removal of emerging organic pollutants (EOPs) from complex aqueous environments has garnered widespread attention. However, the low efficiency and selectivity of current PMS activation for 1O2 generation result in suboptimal EOP degradation. To enhance the selectivity of PMS activation and promote the non-radical pathway, non-metal heteroatoms with varying electronegativities were introduced to disrupt the symmetrical coordination structure of Fe active sites in Fe single-atom catalysts. The results showed that, in the B-Fe1/GLCNs/PMS system, the pseudo-first-order kinetic rate for bisphenol A (BPA) degradation reached 4.435 min–1, which is 7.4 times higher than that of the unmodified control group. Experimental and theoretical calculations demonstrated that the doping of non-metal heteroatoms altered the electron density and distribution at the Fe active sites, thereby modulating the adsorption configuration of HSO5– and increasing the selectivity for PMS activation to generate 1O2. Additionally, the degradation of EOPs by 1O2 produced intermediate products with lower biological toxicity, and 1O2 demonstrated strong anti-interference capability. The change in HSO5– morphology improved the rate of 1O2 generation. This study provides deep insights into designing high-performance PMS activation catalysts via non-metal doping to regulate the electronic structure of active sites for a selective non-radical pathway.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2025
·
IF 4.6
Dongliang Chu,Weiguo Sun,Longsuo Guo,Xiaojun Yang
We obtained a series of B 6 O, B 4 C, ZrB 2 crystals at a pressure of 6 GPa and temperature of 1673–1973 K. These crystals were characterized by XRD and SEM. At a pressure of 6 GPa, the minimum synthesis temperature for B 6 O is 1673 K. The grain size of B 6 O in all the samples remained consistent at around 30–50 nm, with a uniform distribution in each sample. The bonding force between B 6 O grains is weak, and the B 6 O grain size remains relatively stable, showing minimal change with increasing temperature and time. In the sample synthesized at 1973 K, B 6 O icosahedra (multiply twinned particles, MTPs) with a diameter of 12 μm, B 4 C particles with a diameter of 25 μm, and flaky ZrB 2 were observed. We conducted theoretical calculations on B 6 O and B 4 C using density functional theory (DFT).
研究领域:
材料科学
·
无机非金属材料
·
高压物理
·
计算材料学
·
结构表征
✓ 已验证
产品关联
DOI
高影响因子
COMPOSITES PART B-ENGINEERING
·
2025
·
IF 14.2
Ningqiang Shi,Mingyang Wu,Zhijun Li,Jinchang Meng,Chuncheng Ban,Luochen Qu,Mingyu Zhang,Ling Li
Boron nitride nanotubes (BNNTs) offer remarkable potential for thermal management and optoelectronic applications due to their high aspect ratio, excellent thermal conductivity, electrical insulation, and mechanical strength. However, achieving high-quality, well-aligned BNNTs (ABNNTs) remains a critical challenge, largely due to limited understanding of their growth mechanism. Here, we develop a three-dimensional flow–force–thermal coupling model that reveals how gas convection and vertical temperature gradients synergistically drive the aligned growth of ABNNTs. We elucidate the essential roles of thermophoretic and shear forces in guiding nanotube orientation. Based on this insight, a synthesis strategy integrating computational fluid dynamics and thermo-solid coupling analysis is proposed and experimentally validated. The resulting ABNNTs exhibit high crystallinity, low defect density, and near-ideal BN stoichiometry. When applied as thermal interface materials (TIMs) in LED devices, ABNNTs reduce the core temperature by approximately 17.9 °C and enhance thermal dissipation efficiency by ∼20.7 %, outperforming disordered BNNTs and commercial TIMs. This work not only clarifies the fundamental mechanism underlying ABNNT alignment, but also establishes a rational design strategy for advanced thermally conductive materials and their integration into high-performance electronic systems.
研究领域:
材料科学
·
纳米科技
·
热管理
·
电子器件散热
·
功能材料
·
固态物理
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2025
·
IF 6.4
Zhen-Cheng Wu,Fang-Xu Tian,Rui Xiao,Mao-Yin Ran,Wenlong Liu,Wen-Tong Chen,Sheng-Ping Guo
The study of infrared nonlinear optical (NLO) materials with wide band gaps and high laser induced damage thresholds (LIDTs) is an urgent and challenging topic. Here, we report the NLO properties of CsRESiS4 (RE = Sm, Gd–Ho), which were synthesized by the reactive flux CsCl assisted RExOy–B–S routine. The structure of CsRESiS4, [CsS7] pentagonal bipyramids are orderly arranged to populate the interlayer space created by [RES7] monocapped triangular prisms consolidated [SiS4] tetrahedra. They all exhibit wide band gaps of 3.51–3.95 eV, high LIDTs of 3.6–5.5 × AGS, and NLO activity, with CsHoSiS4 possessing the largest band gap among rare-earth chalcogenides. The theoretical calculation results indicate that [RES7] monocapped triangular prisms are the main source of NLO activity and have a wide band gap. This work provides an effective case for exploring wide band gap infrared NLO materials.
研究领域:
材料科学
·
凝聚态物理
·
无机化学
·
光学材料
·
功能晶体
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Guoqing Wang,Pengxing Cui,Longfei Jiang,Lianghao Chen,Peter Tatarko,Fengjun Zhang,Xiaobing Zhou
In this study, a highly dense GdB 6 bulk ceramic material was fabricated using one-step in-situ reaction spark plasma sintering technology. The sample with a relative density of 96.7 % and a purity of 96.9 wt% was successfully obtained by sintering at 1800 °C for 30 min under a uniaxial pressure of 50 MPa. The Vickers hardness , elastic modulus and fracture toughness of the as-obtained GdB 6 bulk ceramics were 18.9 GPa, 209 GPa and 1.6 MPa·m 1/2 , respectively. The thermal conductivity of GdB 6 at room temperature was 28.68 W·m −1 ·K −1 , 70 % of which was mainly attributed to phonon vibration, while the remaining 30 % to the electrical thermal conductivity. In addition, the as-obtained GdB 6 ceramics showed no phase transformation after heat treatment at a relatively high temperature of 2100 °C for 20 min in Ar atmosphere. The highly covalent octahedral boron framework played a critical role in maintaining the phase stability of the GdB 6 crystal lattice . This suggested that GdB 6 ceramics could be used as potential ultra-high temperature ceramics for aerospace applications and high-power vacuum electronic devices operated at high temperatures.
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
Particuology
·
2024
·
IF 4.1
Chen Dong,Yi Wang,Kanghui Jia,Dan Song,Xiaolan Song,Chongwei An
Boron nanoparticles , with their remarkably high gravimetric and volumetric calorific values, emerge as the most promising fuel in energetic fields. However, challenges such as susceptibility to oxidation , high ignition temperature , and low combustion efficiency have constrained their further applications. In this study, we fabricated high explosives based nano-boron microspheres with uniform size using the electrostatic spray method, in which the boron nanoparticles and high explosives (CL-20 or PETN) are closely bonded together by fluorinated polymer (F 2602 ) and evenly distributed. The results indicated that the microspheres exhibited high sphericity and showed an enhanced antioxidant capability. The addition of high-energy explosives not only reduced the thermal oxidation temperature of nano-boron powder within the microspheres but also significantly enhanced the pressurization rate. Additionally, the microspheres with added high-energy explosives released more energy during the combustion process. Compared to physically mixed samples, electrostatically sprayed microspheres with a uniform microstructure still exhibited higher reactivity. Therefore, the design and synthesis of microspheres with controllable structures using the electrostatic spray method show promising application prospects.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2024
·
IF 4.3
Yonghui Yu,Jie Wei,Xianghui Yan,Yuhong Chen,Biao Zhang,Yujin Wang,Feng Ye,Limeng Liu
TaB 2 –SiC composites with 0–20 wt% SiC contents were prepared by reaction hot pressing using Ta, B and SiC powders as starting materials. Densification, constituent phases, microstructure and mechanical properties, namely Vickers hardness, fracture toughness and flexure strength, were evaluated by means of inspection of sintering shrinkage, density measurement, XRD, SEM, TEM, HRTEM, EDS, SAED, indentation and three-point bending tests. Phase formation, including dominant (TaB 2 , SiC) and minor (TaC, glassy SiO 2 ) phases, was checked by thermodynamic assessment relevant with Ta 2 O 5 and B 2 O 3 impurities introduced into the reaction system by the starting powders. The results showed that mixtures of Ta, B and SiC powders would initiate self-propagating combustion synthesis (SPCS) at about 900 °C; a transient hold at 800 °C for 1 h could suppress this reaction. Volatilization of B 2 O 3 impurity in association with local high temperature due to SPCS helped reduce the TaC and glassy SiO 2 minor phase formation. TaB 2 –SiC composites could reach 99 % relative densities with 3 wt% SiC addition and above. Compositions with <7.5 wt% SiC additions showed uniform dispersion of SiC particles at multi-TaB 2 grain junctions while compositions with higher SiC content revealed SiC segregation. Bending strength of 503 MPa and fracture toughness of 6.69 MPa⋅m 1/2 could be reached with 7.5–20 wt% SiC addition.
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
危险品化学品经营许可证（带存储）