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ON HYERS-ULAM STABILITY OF NONLINEAR DIFFERENTIAL EQUATIONS
Jinghao Huang,정순모,Yongjin Li 대한수학회 2015 대한수학회보 Vol.52 No.2
We investigate the stability of nonlinear differential equations of the form y(n)(x) = F(x, y(x), y′(x), . . . , y(n−1)(x)) with a Lipschitz condition by using a fixed point method. Moreover, a Hyers-Ulam constant of this differential equation is obtained.
ON HYERS-ULAM STABILITY OF NONLINEAR DIFFERENTIAL EQUATIONS
Huang, Jinghao,Jung, Soon-Mo,Li, Yongjin Korean Mathematical Society 2015 대한수학회보 Vol.52 No.2
We investigate the stability of nonlinear differential equations of the form $y^{(n)}(x)=F(x,y(x),y^{\prime}(x),{\cdots},y^{(n-1)}(x))$ with a Lipschitz condition by using a fixed point method. Moreover, a Hyers-Ulam constant of this differential equation is obtained.
Hyers-Ulam Stability of Pompeiu's Point
Huang, Jinghao,Li, Yongjin Department of Mathematics 2015 Kyungpook mathematical journal Vol.55 No.1
In this paper, we investigate the stability of Pompeiu's points in the sense of Hyers-Ulam.
Preparation and characterization of chars and activated carbons from wood wastes
Yan Qiangu,Li Jinghao,Cai Zhiyong 한국탄소학회 2021 Carbon Letters Vol.31 No.5
Preparation of activated carbons from wood waste including northern hardwood pins-fnes and wood dust was conducted and then compared through the following methods: physical pyrolysis and CO2 activation, vacuum pyrolysis and CO2 activation, CO2 gasifcation, and vacuum CO2 gasifcation processes. Experimental results show that chars and activated carbons with high surface area and pore volume are produced from wood waste through a vacuum CO2 pyrolysis/gasifcation process. The efects of operation variables of vacuum pyrolysis/gasifcation on the properties of chars and activated carbons were investigated to identify and optimize the temperature, heating time, and heating rate. The optimized vacuum CO2 gasifcation conditions were found to be a temperature of 800 °C, a heating rate of 20 °C/min, and a holding time of 2 h respectively. The prepared wood-chars and activated carbons were characterized by nitrogen physisorption, scanning electron microscopy (SEM). Fourier transform infrared (FTIR) spectra determined any changes in the surface functional groups produced during diferent preparation stages.
Ge Tian,Li Xiong,Wenhua Lin,Jinghao Han,Xiang-Yan Chen,Thomas Wai Hong Leung,Yannie Oi Yan Soo,Lawrence Ka Sing Wong 대한신경과학회 2016 Journal of Clinical Neurology Vol.12 No.3
Background and PurposezzExternal counterpulsation (ECP) is a noninvasive method used to enhance cerebral perfusion by elevating the blood pressure in ischemic stroke. However, the response of the beat-to-beat blood pressure variability (BPV) in ischemic stroke patients during ECP remains unknown. MethodszzWe enrolled recent ischemic stroke patients and healthy controls. Changes in the blood fow velocities in bilateral middle cerebral arteries and the continuous beat-to-beat blood pressure before, during, and afer ECP were monitored. Power spectral analysis revealed that the BPV included oscillations at very low frequency (VLF; <0.04 Hz), low frequency (LF; 0.04– 0.15 Hz), and high frequency (HF; 0.15–0.40 Hz), and the total power spectral density (TP; <0.40 Hz) and LF/HF ratio were calculated. ResultszzWe found that ECP signifcantly increased the systolic and diastolic blood pressures in both stroke patients and controls. ECP decreased markedly the systolic and diastolic BPVs at VLF and LF and the TP, and the diastolic BPV at HF when compared with baseline. Te decreases in diastolic and systolic BPV reached 37.56% and 23.20%, respectively, at VLF, 21.15% and 12.19% at LF, 8.76% and 16.59% at HF, and 31.92% and 23.62% for the total TP in stroke patients, which did not difer from those in healthy controls. Te change in fow velocity on the contralateral side was positively correlated with the total TP systolic BPV change induced by ECP (r=0.312, p=0.035). ConclusionszzECP reduces the beat-to-beat BPV when increasing the blood pressure and cerebral blood fow velocity in ischemic stroke patients. ECP might be able to improve the clinical outcome by decreasing the beat-to-beat BPV in stroke patients, and this should be explored further in future studies.
Sludge deep dewatering enhanced by zero-valent iron/peroxymonosulfate/walnut shell powder
Zhang Yanping,He Miaolin,Xue Xieping,Li Fen,Lv Ning,Dong Jinghao 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.8
To enhance sludge dewatering performance, Zero-valent iron/peroxymonosulfate/walnut shell powder was used to condition sludge at 55 °C and pH=3 (ZVI/PMS/WSP-T/pH), and the dewatering mechanism was also analyzed. The results showed that the capillary suction time (CST) and water content of sludge cake (Wc) were reduced to 6.8 s and 62.1%, respectively, and net sludge yield (YN) increased to 58.74kg/(m2·h) after being treated by ZVI/PMS/WSP-T/pH. The thermal and acid conditions could promote the corrosion of Fe2+ from ZVI and enhance PMS to produce more SO −· 4 and ·OH. The radicals combined with acid and thermal hydrolysis could efficiently reduce extracellular polymeric substances (EPS), especially tightly bound EPS (TB-EPS), destroy sludge floc and release bound water. The stripping off of EPS and neutralization of Fe3+, Fe2+ and H+ caused the zeta potential to increase to −0.91 mV The flocculation of cations and adsorption of WSP further increased the fractal dimension to 1.71. Moreover, the rigid and porosity structure of WSP increased sludge incompressibility and formed channels for water. Under the combined oxidation, acid/thermal hydrolysis, re-aggregation and skeleton builder functions, the sludge dewatering performance was greatly improved.