A FINITE DIFFERENCE SCHEME FOR RLW-BURGERS EQUATION

Zhao, Xiaohong,Li, Desheng,Shi, Deming Korean Society of Computational and Applied Mathem 2008 Journal of applied mathematics & informatics Vol.26 No.3-4

In this paper, a finite difference method for a Cauchy problem of RLW-Burgers equation was considered. Although the equation is not energy conservation, we have given its the energy conservative finite difference scheme with condition. Convergence and stability of the difference solution were proved. Numerical results demonstrate that the method is efficient and reliable.

A finite difference scheme for RLW-Burgers equation

Xiaohong Zhao,Desheng Li,Deming Shi 한국전산응용수학회 2008 Journal of applied mathematics & informatics Vol.26 No.3-4

In this paper, a finite difference method for a Cauchy problem of RLW-Burgers equation was considered. Although the equation is not energy conservation, we have given its the energy conservative finite difference scheme with condition. Convergence and stability of the difference solution were proved. Numerical results demonstrate that the method is efficient and reliable. In this paper, a finite difference method for a Cauchy problem of RLW-Burgers equation was considered. Although the equation is not energy conservation, we have given its the energy conservative finite difference scheme with condition. Convergence and stability of the difference solution were proved. Numerical results demonstrate that the method is efficient and reliable.

Research on the Microstructure Characteristic and Tensile Property of Laser‑MIG Hybrid Welded Joint for 5A06 Aluminum Alloy

Yanqiu Zhao,Xiaohong Zhan,Qiyu Gao,Shuai Chen,Yue Kang 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.3

Laser-metal inter gas (MIG) hybrid welding technique provides higher overall productivity over the traditional fusionwelding processes for joining medium-thick aluminum alloy. In this paper, laser-MIG hybrid welding experiment was performedby the TruDisk 12003 Laser and KUKA robot. The second fusion line, the laser-dominated region and laser-MIGhybrid-dominated region were introduced to this study to discuss the microstructure distribution. A three-dimensionalfinite element model was established by MSC. Marc to study the thermal field distribution of laser-MIG hybrid weldingprocess. It found that the temperature in the laser-MIG hybrid-dominated region was much higher than the laser-dominatedregion. The formation of the second fusion line in the welded joint is mainly owing to the different heat effect of laser-archybrid-dominated region and laser-dominated region. The crystalline size of equiaxed dendrite grains in the laser-MIGhybrid-dominated region is finer than the laser-dominated region. In addition, the tensile property was measured to dissectthe failure mechanism of the laser-MIG hybrid welding joints. The element content in fractured surface at the position ofdimple and pore wall were comprehensively analyzed. The element content of Mg and O in pore wall are higher than dimple. In the solidification process, the growth of equiaxed dendrite grains is in part hindered by the existence of coarse pores inthe laser-MIG hybrid-dominated region.

Triptolide inhibits ovarian cancer cell invasion by repression of matrix metalloproteinase 7 and 19 and upregulation of E-cadherin

Hongxi Zhao,Zhifu Yang,Xiaohong Wang,Xianzhi Zhang,Meng Wang,Yukun Wang,Qibing Mei,Zhipeng Wang 생화학분자생물학회 2012 Experimental and molecular medicine Vol.44 No.11

Triptolide, a compound extracted from the traditional Chinese medicine preparation of Tripterygium wilfordii Hook F., has been reported to have anti-inflammatory and anti-cancer activities. However, its effect on ovarian cancer invasion is unknown. We observed that MMP7 and MMP19 expression increased in ovarian cancer tissue. Triptolide treatment inhibited the migration and invasion of ovarian cancer cells SKOV3 and A2780 at the concentration of 15 nM. We also observed that triptolide suppressed MMP7 and MMP19 promoter activity in a dose-dependent manner,down-regulating the expressions of these promoters on mRNA and protein level. Moreover, triptolide enhanced E-cadherin expression in ovarian cancer cells. In vivo, triptolide inhibited tumor formation and metastasis in nude mice, and suppressed MMP7 and MMP19 expression; it also enhanced E-cadherin expression in tumor in a dose-dependent manner. Over expression of MMP7 and MMP19, or suppression of E-cadherin expression partially abolished the inhibitory effect of triptolide on invasion of ovarian cancer cells. To summarize, triptolide significantly inhibited the migration and invasion of ovarian cancer cells by suppression of MMP7 and MMP19 and up-regulation of E-cadherin expression. This study shows that triptolide is a good candidate for the treatment of ovarian cancer and reduction of metastasis.

An SVD-based SVM with Common-mode Voltage Reduction for Direct Matrix Converters

Quanxue Guan,Xiaohong Wang,Zhuoli Zhao,Lina Wang 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In this paper, a new space vector modulation (SVM) strategy is presented to reduce the output common-mode voltage (CMV) for direct matrix converters. This method modifies the traditional singular value decomposition modulation to enable the usage of switch vectors with 120? phase shift, then substitutes two of the corresponding switch states by an orientation switch state which connects every input to one output phase. Since those orientation switch states have zero CMV at the output side of matrix converters, by this mean, not only the peak value but also the voltage transitions of the CMV are decreased dramatically. Besides, the improvement of the modulation can be implemented by some minor modification in software, and thus not additional costs in hardware are needed. imulation results are shown to corroborate the effectiveness of the proposed method. Index Terms?Common-mode Voltage, Matrix Converters, Singular Value Decomposition, Space Vector Modulation

Influence of Laser Power on Grain Size and Tensile Strength of 5A90 Al–Li Alloy T-joint Fabricated by Dual Laser-Beam Bilateral Synchronous Welding

Shuai Chen,Xiaohong Zhan,Yanqiu Zhao,Youfa Wu,Dongtao Liu 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.6

Dual laser-beam bilateral synchronous welding is introduced to produce the 2.5 mm thick 5A90 Al–Li alloy T-joint. Thegrain morphology and grain size of weld metal (WM) in the T-joint are analyzed and calculated. The tensile experiment,scanning electron microscopy and energy disperse spectroscopy are respectively employed to study the tensile strength,fracture morphology and chemical composition of the T-joint. The results reveal that when the laser power is increased from2500 to 3000 W, the grain sizes of fine-grained layers and columnar dendrites near the fusion line are significantly reduced. Conversely, that of equiaxed dendrites at the WM center is not sensitive to the variety of laser power. Moreover, the degreeof elemental segregation in WM near the fusion line is also aggravated with the increasing of the laser power. The tensilestrength of the T-joint with the laser power of 2500 W is significantly higher than that with the laser power of 3000 W. Thetensile fracture locations are occurred in the weld toe with obvious pores, shear dimples and tear ridges, which are the typicalcharacteristics of ductile fracture. Besides, the chemical compositions of the second phase particles in the WM are moresensitive to than the variation of laser power compared with that of the matrix.

Modulating charge transport characteristics of bis-azaisoindigo-based D-A conjugated polymers through energy level regulation and side chain optimization

Huang, Kaiqiang,Zhao, Xue,Du, Yuchang,Kim, Sanghyo,Wang, Xiaohong,Lu, Hongbo,Cho, Kilwon,Zhang, Guobing,Qiu, Longzhen The Royal Society of Chemistry 2019 Journal of Materials Chemistry C Vol.7 No.25

<P>Six donor-acceptor (D-A) conjugated polymers, P1-P6, based on the novel electron acceptors bis-isoindigo (BIID) and bis-azaisoindigo (BAID), were designed and synthesized for solution-processed organic field-effect transistors with high-performance optical and electrical properties. Energy level regulation was achieved by incorporation of nitrogen and fluorine heteroatoms and side chain optimization to reduce side chain density and extend branching point positions. Both the hole (<I>μ</I>h) and electron mobilities (<I>μ</I>e) significantly increased from P1 to P6, and there was an obvious transition from hole-dominated ambipolar charge transport behavior to highly-balanced ambipolar behavior. Since aza-substitution strengthened the electron-deficient property of the acceptor units, the entire molecular skeleton of BAID-based polymers has a high electron affinity and a low-lying lowest unoccupied molecular orbital (LUMO) level according to ultraviolet photoelectron spectroscopy (UPS) and cyclic voltammetry (CV) measurements. The <I>μ</I>e of BAID-based polymers is an order of magnitude higher than that of BIID-based polymers. In addition, side chain optimization was shown to significantly influence intermolecular interactions and supramolecular self-assembly. The stepwise reduction of the π-π stacking distances of P1-P6 calculated by GIXRD curves supports this conclusion. Finally, in P6 (PBAID3-2FBT), a maximum absorption wavelength (<I>λ</I>max) was observed at 797 nm, a low optical band gap (<I>E</I>g) of 1.27 eV, a low LUMO level of −3.90 eV, and an average <I>μ</I>h and <I>μ</I>e of 1.31 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP>. This paper offers an available molecular design strategy to achieve highly-balanced and high-performance ambipolar charge carrier transport D-A conjugated polymers.</P>

Impact of enhanced recovery after surgery program for hungry bone syndrome in patients on maintenance hemodialysis undergoing parathyroidectomy for secondary hyperparathyroidism

Ling Wang*,Xiaohong Zhang*,Fengqi Hu,Hai Yuan,Zhao Gao,Li He,Shuang Zou 대한외과학회 2022 Annals of Surgical Treatment and Research(ASRT) Vol.103 No.5

Purpose: Hungry bone syndrome after parathyroidectomy is an important clinical problem in patients on maintenance hemodialysis. We examined the effect of an enhanced recovery after surgery (ERAS) program on the incidence of hungry bone syndrome after parathyroidectomy in this population. Methods: This single-institution, retrospective study analyzed 108 patients on hemodialysis who underwent parathyroidectomy for secondary hyperparathyroidism. Patients were classified into the pre-ERAS (n = 52) and post-ERAS (n = 56) groups. The ERAS program identified high-risk patients and enforced aggressive measures to normalize calcium levels following parathyroidectomy. Results: There was no significant difference in age, sex, body weight, presenting symptoms, preoperative calcium and alkaline phosphatase levels, postoperative intact parathyroid levels, postoperative calcium levels at 1 and 24 hours after parathyroidectomy, and 30-day readmission rates between the groups. The post-ERAS group had significantly higher levels of postoperative calcium at 48 and 72 hours after parathyroidectomy, but a lower incidence of hungry bone syndrome and shorter postoperative length of stay. Patients with hungry bone syndrome had higher preoperative levels of alkaline phosphatase and intact parathyroid, longer postoperative length of stay, and were less likely to have been part of the ERAS program. High preoperative alkaline phosphatase levels and absence of the ERAS program were independent risk factors for hungry bone syndrome after parathyroidectomy. Conclusion: The ERAS program reduced the incidence of hungry bone syndrome and shortened the postoperative length of stay in patients on maintenance hemodialysis who underwent parathyroidectomy for secondary hyperparathyroidism.

Bismuth stannate nanoparticles for enhancing fire safety of flexible polyvinyl chloride: Preparation, evaluation, and mechanism

Zhaodong Yuan,Xiaowei Zhao,Shuaiqiang Nie,Xiaohong Li,Zhijun Zhang,Zhiwei Li 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.122 No.-

To replace traditional toxic Sb2O3 flame retardants, Bi2Sn2O7 (BSO) nanoparticles were prepared by a coprecipitationmethod and used as flame retardants of flexible polyvinyl chloride (PVC) for the first time. Structural characterization revealed that as-prepared BSO nanoparticles had a cubic phase with an averagediameter of 20 nm. Under 3 wt% loading, the PVC/BSO composite gained a limiting oxygen index of29%, very close to 29.5% of PVC/Sb2O3. In particular, the PVC/BSO composites passed the UL-94V-0 rating,while PVC/Sb2O3 failed. The PVC/BSO composite also showed better heat and smoke suppression performancethan Sb2O3, with a 27.4% decrease in peak heat release rate and a 39.9% decrease in total smokeproduction, compared with the PVC matrix. The excellent performance is attributed to following two reasons:In the gas phase, similar to Sb, Bi can form BiCl3, which dilutes the combustion gas and captureshydroxyl radicals; In the condensed phase, Sn in BSO helps form more protective char residue with theleast pores and the highest degree graphitization. In addition, the tensile strength and elongation at breakof PVC/BSO were also slightly superior to those of PVC/Sb2O3. In conclusion, BSO nanoparticles will be apromising substitute for toxic Sb2O3 flame retardants.

Changes in Protein Phosphorylation during Salivary Gland Degeneration in Haemaphysalis longicornis

Qi Xiao,Yuhong Hu,Xiaohong Yang,Jianna Tang,Xiaoshuang Wang,Xiaomin Xue,Mengxue Li,Minjing Wang,Yinan Zhao,Jingze Liu,Hui Wang 대한기생충학ㆍ열대의학회 2020 The Korean Journal of Parasitology Vol.58 No.2

The ticks feed large amount of blood from their hosts and transmit pathogens to the victims. The salivary gland plays an important role in the blood feeding. When the female ticks are near engorgement, the salivary gland gradually loses its functions and begins to rapidly degenerate. In this study, data-independent acquisition quantitative proteomics was used to study changes in the phosphorylation modification of proteins during salivary gland degeneration in Haemaphysalis longicornis. In this quantitative study, 400 phosphorylated proteins and 850 phosphorylation modification sites were identified. Trough RNA interference experiments, we found that among the proteins with changes in phosphorylation, apoptosis-promoting Hippo protein played a role in salivary gland degeneration.