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FLOW ANALYSIS AND THEORETICAL DESIGN OF DIESEL ENGINE EXHAUST PORT
Fushui Liu,Yang Xu,Jingmin Rui,Zhongjie Shi,Yikai Li 한국자동차공학회 2020 International journal of automotive technology Vol.21 No.1
Exhaust port is an important part of a diesel engine which affects the combustion and emission. It is important to have a good design for exhaust port. In this paper, the calculation formula of the optimal area ratio (Kopt) of outlet and inlet of exhaust port was derived. The formula shows that Kopt is only determined by relative pressure difference (RPD). Then influence of the area ratio (K) of outlet and inlet on flow capacity of exhaust port and the trend of Kopt with relative pressure difference were studied numerically to verify the validity and applicability of the formula. The numerical results shows that the mass flow rate increases first and then keeps constant with the increase of K at the same RPD. Kopt exists and decreases first and then keeps constant with the increase of RPD. The numerical trend is consistent with theoretical trend and the errors between maximum mass flow rates of numerical results and actual mass flow rates at theoretical optimal area ratios are all less than 5 % meeting engineering accuracy. It is indicated that the derived formula is correct and applicable. When an exhaust port is designed, the outlet area can be estimated by this formula.
WEI Zhendong,DU Jingmin,LIAO Lihui,Yang Gang,LI Baoren 유공압건설기계학회 2015 유공압건설기계학회 학술대회논문집 Vol.2015 No.10
According to theory of phononic crystals (PCs), a ship hydraulic pipeline isolator with one-dimensional periodic composite structure is designed, which is composed of metal and rubber. The vibration of ship hydraulic pipeline can be suppressed by the band gaps (BGs) of the isolator. The band structure and frequency response function (FRF) of the isolator is figured out by the finite element method (FEM). To obtain the best frequency ranges and width of the BGs, the influences of various material, lattice constant and fineness ratio are considered, and the best structure parameters were also obtained. The results revealed that the isolator has axial vibration BGs with frequencies from 400 Hz to 10000 Hz, and the maximum vibration attenuation is up to 150 dB. The research provides a new technical method to control vibration of ship hydraulic pipeline.
Qianwen Xie,Xueyin Chen,Jingmin Xiao,Shaonan Liu,Lihong Yang,Jing Chen,Jiaqi Lai,Rui Lan,Yi Chen,Haifang Yang,Xinfeng Guo 한국한의학연구원 2020 Integrative Medicine Research Vol.9 No.4
Background: The evidence of Acupuncture combined with speech rehabilitation training for post-stroke dysarthria is insufficient and there is no consensus on its efficacy. Methods: We searched seven Chinese and English medicine databases for randomized controlled trials (RCTs) from their inception to November 2019. The primary outcome measure was the clinical response rate, assessed with the Frenchay Dysarthria Assessment (FDA) tool. We assessed risk of bias using the Cochrane risk-of-bias tool. We used GRADE to assess the certainty of evidence (CoE). Results: Thirty studies were included in this systematic review, 23 of which were pooled in meta-analysis. Acupuncture combined with speech rehabilitation training is likely beneficial for was response rate (n = 1685; RR = 1.37; 95% CI [1.29, 1.46], P < 0.01, I2 = 34%; 17 studies, low CoE) compared to speech rehabilitation treatment alone. Conclusion: The combination of acupuncture and speech rehabilitation training may improve total response rate of stroke patients with dysarthria. However, more RCTs with rigorous study design and validated outcome measures are needed to confirm the evidence.
Wu Yaran,Cai Lei,Xie Xingzi,Yang Shuying,Shi Qing,Jia Hongzhe,Gu Xuqiang,Deng Jingmin,Shi Mingzhao,Chen Qiuping,Cao Shaoqian,Cai Shuangfeng 한국응용생명화학회 2022 Applied Biological Chemistry (Appl Biol Chem) Vol.65 No.2
Resistant starch could be degraded by the fermentation of colonic microorganisms in the large intestine of mammals, but not in the small intestine. In this study, we established a novel strategy by using resistant starch as an endogenous marker to determine the glucose absorption of the small intestine of laboratory animals. By optimization of the classical enzymatic method of starch measurement, the demand for the sample weight was reduced by 90%. Moreover, the amount of resistant starch in normal feed was detectable without any extra addition. The value of small intestine glucose absorption of mice was similar when using resistant starch and titanium dioxide as inert markers. The fermentation of resistant starch by intestinal microorganisms in the small intestine was demonstrated not disturbing the detection of glucose absorption significantly. Artificial sweeteners exposed ICR mice showed different glucose absorption which indicated, first, resistant starch can be used as a novel endogenous marker in the small intestine of small animals; second, although glucose tolerance did not change in mice after short-term exposure to artificial sweeteners, there were significant changes in glucose absorption associated with it; third, the short-term exposure resulted in no significant change in glucose tolerance.