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COORDINATING PRICING AND INVENTORY DECISIONS IN A BOUNDED PRODUCTION SYSTEM WITH UNCERTAIN YIELD

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Journal of Systems Science and Systems Engineering 2010年第4期19卷 481-495页

作者： Juliang ZHANG yongjian li Minghui LAI Department of Logistics Management School of Economics and Management Beijing Jiaotong University Business School Nankai University Tianjin 300071 China

Most inventory researches assume that production level can fluctuate arbitrarily. However, large fluctuation of the production level in many firms may be much costly. This paper addresses the coordinating pricing and inventory control problem in a bounded production system with uncertain yield, in which the production level is constrained between a maximum and minimum level in each period and the price can be adjusted dynamically. We show that the optimal policy is the interval base-stock-list-price policy. Also, we study the impact of the production bounds and uncertainty of the yield on the production system. Numerical experiments are also performed to study the impact of parameters on the system.

关键词： Production system dynamic pricing inventory control uncertain yield

Friction between a single platelet and fibrinogen

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Friction 2024年第10期12卷 2344-2354页

作者： Yuhe WANG Yan li Shuguang ZHANG Haosheng CHEN yongjian li State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Key Laboratory of Agricultural Information Acquisition Technology Ministry of Agriculture and Rural AffairsChina Agricultural UniversityBeijing 100083China

Friction has been considered to mediate physiological activities of cells,however,the biological friction between a single cell and its ligand-bound surface has not been thoroughly ***,we established a friction model for single cells based on an atomic force microscopy(AFM)combined with an inverted fluorescence microscopy(IFM)to study the friction between a highly sensitive platelet and fibrinogen-coated *** study revealed that the friction between the platelet and fibrinogen-coated tip is mainly influenced by specific ligand–receptor ***,we modeled the biological friction,which consists of specific interaction,non-specific interaction,and mechanical ***,the results suggested that the velocity can also affect specific ligand–receptor interactions,resulting in the friction change and platelet adhesion to fibrinogen *** study built a friction model between a single cell and its ligand-bound surface and provided a potential method to study the biological friction by the combination of AFM and IFM.

关键词： friction single cell platelet fibrinogen atomic force microscopy(AFM)

Role of Dongchongxiacao (Cordyceps) in prevention of contrast-induced nephropathy in patients with stable angina pectoris

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Journal of Traditional Chinese Medicine 2013年第3期33卷 283-286页

作者： Kai Zhao yongjian li Hong Zhang Department of Cardiology Tianjin Nankai Hospital

OBJECTIVE： To study the preventative effects of Dongchongxiacao （Cordyceps） on contrast-induced nephropathy （CIN） in patients with stable angina pectoris （SAP）. METHODS： One-hundred and three SAP inpatients were divided randomly into two groups： basic treat- ment （n=51） and Dongchongxiacao （Cordyceps） treatment （n=52）; corbrin capsules （3 g; t.d.s.） were used 3 days before angioplasty and 3 days after an- gioplasty）. Serum creatinine （Scr） was assessed at the time of hospital admission and 1, 2, and 3 days after angioplasty. Values of kidney injury mole- cule-1 （KIM-1）, neutrophil gelatinase-associated li- pocalin （NGAL） and interleukin （IL） 18 in the kidney were detected before angioplasty and 1 day after angioplasty in the patients of both groups. The prevalence of CIN between the two groups was then compared. RESULTS： CIN occurred in 9 of 103 patients （8.74%）. The prevalence of CIN in the Dongchongxiacao （Cordyceps） treatment group was lower than that of the basic treatment group （5.77% vs 11.76%） but the difference was not significant （P〉0.05）. The post-procedure mean peak of Scr, post-procedure increase in Scr levels from baseline, and urine levelsof KIM-1, NGAL and IL18 after the procedure in the Dongchongxiacao （Corclyceps） treatment group were significantly lower than those in the basic treatment group （P〈0.05）. CONCLUSION： Prophylactic treatment with Dongchongxiacao （Cordyceps） in SAP patients who undergo coronary angiography or coronary inter- vention could prevent contrast-induced renal im- pairment.

关键词： Cordyceps sinensis, Angina pectoris Cre-atinine Contrast-induced nephropathy

Investigation on hydrodynamic lubrication of bearings in a left ventricular assisted device

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Friction 2020年第4期8卷 746-754页

作者： Xiaobing ZHENG yongjian li Haosheng CHEN Shengshou HU Jianye ZHOU State Key Laboratory of Cardiovascular Disease Fuwai HospitalNational Center for Cardiovascular DiseasesChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100037China State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China

Formations of clots were found inside the hydrodynamic bearings of the left ventricular assisted devices (LVADs) and caused tremendous risks to the long-term use of these devices. For the hydrodynamic bearings used in the LVAD, not only the lubrication status but also the motion of the blood cells in the bearing will take great effect on the performance of the device. Based on the analysis of the hydrodynamic pressures distribution and the flowing trajectory of red blood cells in the lubrication film, the bearing is designed in a region where enough hydrodynamic pressure is generated to float the rotor to reduce the wear, and the entrainment of red blood cells in the gap of the bearing can be prevented to avoid the formation of clots.

关键词： hydrodynamic lubrication journal bearing left ventricular assisted device clot

A microfluidic bleeding model to investigate the effects of blood flow shear on microvascular hemostasis

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Friction 2022年第1期10卷 128-141页

作者： Xiangyu HU Haosheng CHEN Jiang li Kuilin MENG Yuming WANG yongjian li State Key Laboratory of Tribology.Tsinghua University Beijing 100084China School of Mechanical Engineering.University of Science and Technology Beijing Beijing 100083China

Hemorrhage is the phenomenon of blood loss caused by vascular trauma or other pathological reasons,which is life-threatening in severe *** microhemorrhage is difficult to visually monitor and pre-treat in vivo,it is necessary to establish in vitro prediction methods to study the hemostasis mechanism in different physiological *** this study,a microfluidic bleeding model was developed to investigate the effect of blood flow shear on microvascular *** results indicated that the regulation of blood shear rate on platelet aggregation affected the growth and morphology of hemostatic thrombus,and finally regulated the process of *** in vitro model is significant to studies on hemostatic mechanisms,a reliable prediction of microhemorrhages,and an adjustment of the treatment scheme.

关键词： stasis fluid bleeding

Experimental study on the special shear thinning process of a kind of non-Newtonian fluid

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Science China(Technological Sciences) 2007年第2期50卷 138-143页

作者： CHEN HaoSheng CHEN DaRong WANG JiaDao li yongjian State Key Laboratory of Tribology Tsinghua UniversityBeijing 100084China

To study the effect of long chain molecule and surface active agent on non-Newtonian fluid properties, rheological experiments on two different fluids have been done. The first group of the fluid is the hydroxyethyl cellulose water solution, and the second is the water solution containing the mixture of dodecyl- triethyl ammonium bromide and lauryl sodium sulfate. With the increasing shear rate, shear thinning phenomenon appears in the first group of solution, and a spe- cial shear thickening-shear thinning phenomenon appears in the second group. It is considered that the special rheological phenomenon is caused by the difference between the aggregating and the departing speed of the colloidal particles formed in the fluid. The difference between the two speeds relates with the shear rate. The experiment results indicate that the rheological properties can be designed by choosing proper additives at a certain shear rate, and such a fluid with special vis- cosity variation should be included in the classification of the non-Newtonian fluid.

关键词： non-Newtonian fluid rheology shear thinning

Effect of Dongchongxiacao(Cordyceps) therapy on contrast-induced nephropathy in patients with type 2 diabetes and renal insufficiency undergoing coronary angiography

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Journal of Traditional Chinese Medicine 2015年第4期35卷 422-427页

作者： Zhao Kai li yongjian Gao Sheng lin Yu Department of Cardiology Tianjin Nankai Hospital

OBJECTIVE: To study the protective effects of Dongchongxiacao(Cordyceps)(DCXC) on contrast-induced nephropathy(CIN) in patients with type 2 diabetes and renal insufficiency undergoing coronary ***: A total of 120 patients with type 2 diabetes whose estimated glomerular filtration rate(e GFR) was ≤ 60 m L/minee grou·1.73 m2,were divided randomly into thrps,basic treatment group(n = 41),standard DCXC therapy group(n = 39,2-g corbrin capsules,3 times/d,3 days before and after angiography),and intensive DCXC therapy group(n = 40,3-g corbrin capsules,3 times/d,3 days before and after angiography). Serum creatinine(Scr)and e GFR were assessed at the time of admission to hospital,and on days 1,2 and 3 after angiography. Urine neutrophil-gelatinase-associated-lipocalin(NGAL),kidney injury molecule-1(KIM-1) and interleukin-18(IL-18) were measured before angiography and at day 1 after angiography for all patients. The primary end point was the prevalence of CIN. The secondary end point was a 25% or greater reduction in e ***: CIN occurred in 11 of 120 patients(9.17 %). The prevalence of CIN was lower in the DCXC treatment groups than in the basic treatment group(P < 0.05),with a more significant decrease in the prevalence of CIN in the intensive DCXC therapy group(P < 0.01). Compared with the basic treatment group,a lower proportion of patients in the DCXC treatment groups had an e GFR decrease of 25% or greater(P < 0.05); patients with an e GFR decrease of 25% or greater accounted for an even lower proportion in the intensive DCXC therapy group(P < 0.01). Within 1 day of the procedure,urine levels of KIM-1,NGAL and IL-18 in patients in the intensive DCXC therapy group were lower than those in the basic treatment group and standard therapy group(P < 0.05).CONCLUSION: DCXC treatment may protect against CIN in patients with type 2 diabetes and renal insufficiency undergoing coronary angiography,with intensive DCXC therapy being more effective.

关键词： Cordyceps sinensis Diabetes mellitus Type 2 Coronary angiography Contrast-induced nephropathy

Risk identification,future value and credit capitalization:Research on the theory and policy of poverty alleviation by internet finance

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China Finance and Economic Review 2016年第3期5卷 38-50页

作者： li yongjian Wang Chengqing National Academy of Economic Strategy of Chinese Academy of Social Sciences

Elimination of poverty is an important part to achieve a comprehensive well-off in China,and financial means and tools play an important role on *** paper tries to show the problems in current financial poverty alleviation practice,such as the lack of unified organization,high cost,poor sustainability,uncertain effects,etc.,and illustrates that internet finance,based on new information technologies which enable more comprehensive information collection of poverty population and employ future-oriented valuation method,can help the poor households accumulate credit capital and play a greater role in the process of poverty *** paper also puts forward some policy recommendations to support internet finance in poverty alleviation.

关键词： internet finance financial poverty alleviation poverty alleviation

A mass-conservative average flow model based on finite element method for complex textured surfaces

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Science China(Physics,Mechanics & Astronomy) 2013年第10期56卷 1909-1919页

作者： XIE Yi li yongjian SUO ShuangFu liU XiangFeng li JingHao WANG YuMing State Key Laboratory of Tribology Tsinghua University

A mass-conservative average flow model based on the finite element method(FEM) is introduced to predict the performances of textured surfaces applied in mechanical seals or thrust *** this model,the Jakobsson-Floberg-Olsson(JFO) boundary conditions are applied to the average flow model for ensuring the mass-conservative ***,the non-uniform triangular grid is utilized,which can deal with the problem of complex geometric *** adopting the modeling techniques,the model proposed here is capable of dealing with complex textured *** algorithm is proved correct by the numerical *** addition,the model is employed to gain further insight into the influences of the dimples with different shapes and orientations on smooth and rough surfaces on the load-carrying capacity.

关键词： mass-conservative average flow model complex textured surfaces JFO boundary conditions finite element method