Microstructure and mechanical properties of hot pressed WC matrix composites toughened by commercial Al2O3 and ?-Al2O3 particulates

Haixia Qu 한양대학교 세라믹연구소 2013 Journal of Ceramic Processing Research Vol.14 No.3

Tungsten carbide (WC) matrix composites toughened by commercial alumina (Al2O3) composed of boehmite (AlOOH), χ- Al2O3 and amorphous Al2O3 (WA1) and α-Al2O3 (WA2), respectively, were prepared by high energy ball milling and the following hot pressing, respectively. The microstructure and mechanical properties of WA1 and WA2 were characterized and compared. The results showed that the content of ditungsten carbide (W2C) in the sintered WA1 composites was much smaller than that of WA2 because the phase transformation of the commercial Al2O3 in WA1 suppressed the decarburization of WC; The Vickers hardness and fracture toughness of WA1 were higher than that of WA2 due to the smaller WC grain size and Al2O3 particulate size resulted from the phase transformation of the commercial Al2O3 in WA1. The lower density and worse particulate/matrix interfacial combining conditions of WA1 compared with that of WA2, resulting from the phase transformation of the commercial Al2O3, were responsible for its lowered flexural strength.

Seismic Performance of Encased Steel Plate-Reinforced Gangue Concrete Composite Shear Walls

Haixia Zhang,He Liu,Guochang Li,Xin Ning 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.7

In this paper, a new type of shear wall, referred to as encased steel plate-reinforced gangue concrete composite shear wall, is proposed. To investigate the seismic performance of the shear wall, one of the specimens was subjected to monotonic loading, and the remaining 5 specimens were tested under reversed cyclic loading. The failure mode, hysteretic and skeleton curve, strength degeneration, stiffness degeneration, ductility and energy dissipation capacity of these specimens were compared and analyzed. In addition, finite element models were also established and verified using the test results. Furthermore, the effects of the height-towidth ratio and the axial compression ratio on the seismic behavior of the composite wall were explored. The experimental and numerical results indicate that the specimen has a large load-carrying capacity, excellent ductility and energy dissipation capacity, little strength degradation and minimal stiffness degradation. Moreover, the results also show that the method of welded stiffened short reinforcement on the surface of the steel plate can significantly improve the bond interaction between the steel plate and gangue concrete to maintain the overall work performance of gangue concrete and steel as well as the load bearing capacity of the specimen.

Structure properties and electrical mechanisms of Si(001)/SiO2 interface with varying Si layer thickness in nano-scale transistor

Haixia Li,Aiming Ji,Canyan Zhu,Ling-Feng Mao 한국물리학회 2018 Current Applied Physics Vol.18 No.9

To illustrate the impacts of stress/strain effect on nano-scale transistor, a theoretical investigation of stress/strain and transition region of interface are presented in this paper. It is found that the residual stress changes from −1.8098 to 0.3159 GPa with Si layer thickness increasing. At the same time, SiSi average bond length reduces from 2.397Å to 2.355 Å and finally approaches to 2.352 Å (the bond length of ideal silicon crystal). The further calculations demonstrate that the above mentioned changes also decrease surface potential. And the relative decrease in the surface potential becomes larger with the applied gate voltage decreasing especially when it is less than 1.5 V. Moreover, when the doping concentration is 1 × 1019cm−3, the threshold voltage and subthreshold swing (SS) reduce from 2.9 V to 2 V and 551mV/dec to 198mV/dec respectively. It implies that we can get a better device performance by growing appropriate thickness of silicon.

Comparative Studies on Structure-Property Relationships of the Polyimide Films Derived from the Dianhydride Containing Alicyclic cis-Ethylenic Double Bond

Haixia Qi,Qingmin Liu,Anran Zhang,Feng Liu,Ning Zhang 한국고분자학회 2019 Macromolecular Research Vol.27 No.7

An ester dianhydride bearing alicyclic cis-ethylenic double bond, bicyclo [2.2.1]hept-5-ene-2, 3-diylbis(methylene)bis(1, 3-dioxo-1, 3-dihydroisobenzofuran- 5-carboxylate) (BHEM) and its hydrogenated analogue bicyclo[2.2.1]heptane-2, 3- diylbis(methylene)bis(1, 3-dioxo-1, 3-dihydroisobenzofuran-5-carboxylate) (BHSM) were synthesized and polymerized with three aromatic diamines, respectively, to prepare two analogous series of polyimide (PI) films. Comparative studies were carried out to elucidate how the unsaturated bicylo[2.2.1]heptenyl structure and the saturated bicyclo[2.2.1]heptyl structure in polymer main chain influence the properties of the PI films. The structural characteristics of the two analogous alicyclic structures including reactivity, bulkiness, configuration, polarity were found to impact the solubility, hydrophobicity, surface morphology, and the thermal, optical and dynamic dielectric properties of PI films. The aggregation state of both series of PI films was analyzed by wide-angle X-ray scattering (WAXD) and computed tomography (CT) fluorescence, which reveals the structural characteristics differences between unsaturated alicyclic containing cis-ethylenic double bond with planar sp2 hybrid configuration and saturated alicyclic with wholly tetrahedral sp3 hybrid configuration. It indicates that the thermally crosslinkable alicyclic cis-ethylenic double bonds in BHEM incline to induce a closer polarized chain packing via inter-chain π-π complex, while the wholly tetrahedral sp3 configuration of the bulkier saturated alicyclic in BHSM inhibits the chain aggregation in the PI film and leads to greater chain mobility.

A New BISON-like Construction Block Cipher: DBISON

Haixia Zhao,Yongzhuang Wei,Zhenghong Liu 한국인터넷정보학회 2022 KSII Transactions on Internet and Information Syst Vol.16 No.5

At EUROCRYPT 2019, a new block cipher algorithm called BISON was proposed by Canteaut et al. which uses a novel structure named as Whitened Swap−Or−Not (WSN). Unlike the traditional wide trail strategy, the differential and linear properties of this algorithm can be easily determined. However, the encryption speed of the BISON algorithm is quite low due to a large number of iterative rounds needed to ensure certain security margins. Commonly, denoting by n is the data block length, this design requires 3n encryption rounds. Moreover, the block size n of BISON is always odd, which is not convenient for operations performed on a byte level. In order to overcome these issues, we propose a new block cipher, named DBISON, which more efficiently employs the ideas of double layers typical to the BISON-like construction. More precisely, DBISON divides the input into two parts of size n/2 bits and performs the round computations in parallel, which leads to an increased encryption speed. In particular, the data block length n of DBISON can be even, which gives certain additional implementation benefits over BISON. Furthermore, the resistance of DBISON against differential and linear attacks is also investigated. It is shown the maximal differential probability (MDP) is 1/2n-1 for n encryption rounds and that the maximal linear probability (MLP) is strictly less than 1/2n-1 when (n/2+3) iterative encryption rounds are used. These estimates are very close to the ideal values when n is close to 256.

Study on ultra-high sensitivity piezoelectric effect of GaN micro/nano columns

Haixia Zhang,Xiaodong Hu,Hua Zong,Jianbo Fu 나노기술연구협의회 2019 Nano Convergence Vol.6 No.33

High-quality GaN micro/nano columns were prepared with self-organized catalytic-free method. Young’s modulus of GaN nanocolumns were measured under both compressive stress and tensile stress. It was found that the Young’s modulus decreases with the increasing of nanocolumn diameter due to the increase of face defect density. Furthermore, we measured the piezoelectric properties and found that there was a 1000-fold current increase under a strain of 1% with a fixed bias voltage of 10 mV. Based on the Schottky Barrier Diode model, we modified it with the effect of polarization charge, image charge and interface state to analyze the experiment results which reveals that the strong piezopolarization effect plays an important role in this phenomenon. Therefore, the GaN nanocolumns has a great prospect to be applied in high-efficiency nanogenerators and high-sensitivity nanosensors.

Rheinic acid ameliorates radiation‑induced acute enteritis in rats through PPAR‑γ/NF‑κB

Haixia Sha,Yu Gu,Weixing Shen,Li Zhang,Fei Qian,Yudong Zhao,Haixiao Li,Ting Zhang,Weimin Lu 한국유전학회 2019 Genes & Genomics Vol.41 No.8

Background Acute radiation enteritis (ARE), a common complication of intestinal caused by abdominal and pelvic radiation therapy. Rheinic acid is a major active ingredient derived from Rhubarb. Rhubarb could suppress inflammation, tumor, fibrosis oxidative damage. However, RA as the main active component and extract monomer of Rhubarb, the pharmacological activity and the underlying molecular mechanism on various diseases has not yet been revealed. Objective To determine the potential role of rheinic acid (RA) in ameliorating inflammation of rats with acute radiation enteritis (ARE), and explore the underlying mechanism. Methods ARE rat model was established by irradiated with single-dose 10 Gy X-rays at a rate of 0.62 Gy/min to the abdomen. The rats were executed after orally administered with Rheinic acid 7 days and used in the subsequent experiments. Body weight, fecal characteristics and bloody of rats were used to assess the disease activity index. Histological analysis of the jejunum and colon were evaluated using H&E staining. The pro-inflammatory cytokines levels were measured by immunohistochemistry and ELISA. The levels of nitric oxide (NO), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) were also determined. The mRNA and protein expression were examined by real-time polymerase chain reaction (qRT-PCR) and western blot, respectively. Results Rheinic acid promoted intestinal functional recovery, and ameliorated intestinal damage and bloody stool in ARE rats. Rheinic acid strongly decreased the levels of tumor necrosis factor-α, interleukin-1, interleukin-6, NO, and MDA, whereas increased levels of anti-oxidants, SOD and GSH. Moreover, the expression of apoptosis-related proteins, cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase (PARP), were decreased with RA treatment. Further study indicated that PPAR-γ was activated and thereby NF-κB and p38 MAPK signaling pathway were suppressed after rheinic acid treatment. Conclusion Rheinic acid could ameliorate acute radiation enteritis and the underlying molecular mechanism is, at least partially, through PPAR-γ/NF-κB and p38 MAPK/JNK pathways.

Green synthesis of gold nanoparticles using Acorus calamus leaf extract and study on their anti-alzheimer potential

Haixia Peng,Shuzhen Zhang,Qiaolian Chai,Zhongchang Hua 한국생물공학회 2024 Biotechnology and Bioprocess Engineering Vol.29 No.1

Nowadays, the fabrication and characterization of plant extract-based gold nanoparticles (AuNPs) as well as their anticancer activities have gained signifi cant attention. Acorus calamus is a typical Chinese medicinal herb that has been utilized since a period of thousand years for treating rheumatism, asthma, tracheitis, etc. In the current study, the reaction parameters are optimized for managing the size of NPs as categorized by the high-resolution transmission electron microscopy. Various characterization methods such as X-ray diff raction, UV-visible spectroscopy and Fourier-transform infrared spectroscopy were carried out to confi rm the fabrication of AuNPs mediated by the leaf extract of A. calamus. Further, the neuroprotective potential of fabricated AuNPs was studied by evaluating the cholinesterase inhibitory activity and antioxidant potential. The nanogold aqueous extracts exhibited the highest antioxidant and anti-acetyl cholinesterase activity, confi rming that AuNPs can cross the blood-brain barrier and raise the level of acetyl cholinesterase, at the same time reduces the oxidative stress levels. The obtained results concluded their important potential for development of anti-Alzheimer drug having antioxidant and anticholinesterase activity against oxidative stress.

Effect of magmatic hydrothermal on gas reservoir formation in Permian-Lower Triassic source rocks in Huangqiao Area, South China

Haixia Ge,Zhihuan Zhang 한국자원공학회 2016 Geosystem engineering Vol.19 No.6

The main source rocks for gas reservoirs in Huangqiao area of Lower Yangtze region in south China are Permian-Lower Triassic marine strata with high maturity, including carbonate and clastic rocks. A series of geochemical experiments have been carried out in order to reveal the forming mechanism of large gas reservoirs. Geochemical characteristics of crude oils show the source kitchen, which contributes to the large gas reservoir formation, has changed from kerogen cracking to oil cracking. Based on the results of geological evidences, abnormal distribution of vitrinite reflectance, and fluid inclusion characteristics, magmatic hydrothermal is believed to be existed in Huangqiao area. The magmatic hydrothermal changes the source kitchen in two ways. First, the source rock evolution is accelerated by thermal provided by magmatic hydrothermal. Second, it provides hydrogen in the water contained in magmatic hydrothermal to improve liquid hydrocarbons transforming into gases. Thus, the magmatic hydrothermal might considered to be an important factor forming large-scale gas reservoirs in South China.

Nanostructured Lithium Nickel Manganese Oxides for Lithium-Ion Batteries

Deng, Haixia,Belharouak, Ilias,Cook, Russel E.,Wu, Huiming,Sun, Yang-Kook,Amine, Khalil The Electrochemical Society 2010 Journal of the Electrochemical Society Vol.157 No.4