A Venture Capital Portfolio Model Based on Considering the allocation of both Capital Investment and management input

Peng Fei,Zhang Wei-guo,Tang Hai-rong 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

The essence of Venture Capital is to nurture entrepreneurship and development by Capital support and consultive management services, which shows that venture capitalists" management support is of the same importance to the success of venture businesses as the capital support. The inputs of management and the investment of capital will together affect venture capitalists" specific choices of venture businesses. Assume that venture capitalists and venture entrepreneurs can reach an optimal contract, we put forward management input influence coefficient function, discussed its characters and constructed a general venture capital portfolio model and simplified model based on variance analysis by defining an management input impact factor and an expected profit function of a venture capital portfolio which is affected by the management input. A numerical example showed that optimize the allocation of funds and management input synthetically is very important for venture capital porfolio.

Research on Online Reviews Diagnosis’ Effects on Perceptual Information Symmetry

PengFei Qin,JinDan lyu,Yi Zhao ASCONS 2021 INTERNATIONAL JOURNAL OF EMERGING MULTIDISCIPLINAR Vol.5 No.2

Background/Objectives: In this thesis, an empirical study was conducted on consumers’ diagnosis on online reviews in the process of purchasing. Methods/Statistical analysis: In order to verify the viewpoint of this research, this study chooses consumers who have the experience of searching online reviews as the research object, collects data based on a questionnaire from 64 men and 61 women and uses Smart PLS to verify the structural model. Findings: The results of this research are as follows: first, the review diagnosticity sufficiency has positive (+) effects on perceptual information symmetry. Second, the diagnosis on positive online reviews has positive (+) effects on perceptual information symmetry. Third, the diagnosis on negative online reviews has positive (+) effects on perceptual information symmetry. Improvements/Applications: The implications of this study are verifies the effects of the diagnosis of commodities’ online reviews, diagnosis of positive and negative online reviews on consumers’ perceptual information symmetry.

Model Predictive Path Planning Based on Artificial Potential Field and Its Application to Autonomous Lane Change

Pengfei Lin,Woo Young Choi,Seung-Hi Lee,Chung Choo Chung 제어로봇시스템학회 2020 제어로봇시스템학회 국제학술대회 논문집 Vol.2020 No.10

In this paper, we propose a vehicle lane change system using model predictive path planning (MPPP) based on the artificial potential field (APF) for speeding vehicles. It is shown that APF has high performance in real-time obstacle avoidance. However, it remains unpractical for self-driving cars because the point model used for the APF ignores the lateral vehicle dynamics for the lane-keeping system. To resolve the problem, this paper introduces a novel curve-fitting method combined with the APF applied to plan a drivable path for autonomous vehicles in the lane change action. The proposed system was validated through MATLAB/Simulink with the empirical kinematic model. The simulation results indicate that the model predictive path planning algorithm is highly effective in high-speed lane change scenarios to avoid dynamic obstacle vehicles.

Numerical studies on cavitation behavior in impeller of centrifugal pump with different blade profiles

Pengfei Song,Yongxue Zhang,Cong Xu,Xin Zhou,Jinya Zhang 한국유체기계학회 2015 International journal of fluid machinery and syste Vol.8 No.2

To investigate the influence of blade profiles on cavitation behavior in impeller of centrifugal pump, a centrifugal pump with five different blade profiles impellers are studied numerically. The impellers with five different blade profiles (single arc, double arcs, triple arcs, logarithmic spiral and linear -variable angle spiral) were designed by the in-house hydraulic design code using geometric parameters of IS 150-125-125 centrifugal pump. The experiments of the centrifugal pump have been conducted to verify numerical simulation model. The numerical results show that the blade profile lines has a weak effect on cavitation inception near blade inlet edge position, however it has the key effect on the development of sheet cavitation in impeller, and also influences the distribution of sheet cavitation in impeller channels. A slight changing of blade setting angle will induce significant difference of cavitation in impeller. The sharp changing of impeller blade setting angle causes obvious cavitation region separation near the impeller inlet close to blade suction surface and much more flow loss. The centrifugal pump with blade profile of setting angle gently changing (logarithmic spiral) has the super cavitation performance, which means smaller critical cavitation number and lower vapor cavity volume fraction at the same conditions.

Microwave heating assisted synthesis of novel SnSe/g-C3N4 composites for effective photocatalytic H2 production

Pengfei Chen,Xiaoquan Dai,Pingxing Xing,Xinyue Zhao,Qingle Zhang,Shifeng Ge,Jianxiao Si,Leihong Zhao,Yiming He 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.80 No.-

Novel SnSe/g-C3N4 photocatalysts were one-step synthesized via a microwave heating assisted process in35 min with SnSe and melamine as precursors. The as-synthesized SnSe/g-C3N4 worked very well in H2evolution via photocatalysis. Under simulated sunlight, the best SnSe/g-C3N4 sample displayed a H2-production velocity of 1064 mmol g 1 h 1, which is 1.8 folds faster than that of neat g-C3N4. Similarpromotion effect was also observed under visible light. To reveal the nature behind the highphotoactivity, a thorough investigation was performed. XRD and XPS experiments proved the binaryconstitution of the composite. DRS experiment demonstrated that the addition of SnSe improved thephotoabsorption performance. N2-adsorption analysis showed that the SnSe/g-C3N4 photocatalystpresented similar surface area as g-C3N4. TEM experiments showed that some bulk SnSe werespontaneously decomposed to nanoparticles andfinely dispersed in g-C3N4 during the microwaveheating process. These SnSe nanoparticles were believed to be the active phase and constructed aheterojunction structure with g-C3N4, resulting in the enhanced charge separation. This conclusion wasconsidered as the key factor leading to the high H2-evolution performance and was further confirmed bythe PL, EIS, and PC experiments. The present work provides a feasible and rapid method for theconstruction of g-C3N4 based photocatalysts.

A simple method of correcting the parallel plate rim shear stress for non-Newtonian behavior

Pengfei Liu,Yang Wang,Yee-Kwong Leong,Seung Hyuk Kwon,최형진 한국유변학회 2020 Korea-Australia rheology journal Vol.32 No.2

In the rheological characterization of non-Newtonian fluids in a steady torsional shear flow using a parallelplate geometry, there is a need to correct the shear stress at the rim for non-Newtonian behavior. Solving the governing torsional flow equation inversely by Tikhonov regularization using experimental torque vs. rim shear rate data is the most scientific method for obtaining the model independent shear stress. In this short communication, a simple empirical method based on using the derivative of the polynomial fit to torque vs. rim shear rate to correct for the shear stress is presented. This method can be applied to any fluid behavior. The accuracy of this method was confirmed by the outstanding agreement of between the shear stress results of the two methods of polynomial and the inverse problem for magnetorheological fluids. The performance of other correction methods was also discussed.

Analyzing the Effects of VR&AR Industry on Regional Economic Development : Focused on Guangdong Province in China

PengFei Li,이운형 한국디자인트렌드학회 2019 한국디자인포럼 Vol.24 No.2

Background The virtual reality (VR&AR) industry has been a fast-growing industry in the world since 2015. As a key area in China's science and technology and entertainment industry, Guangdong Province, accelerating the development of virtual reality industry will be beneficial to the adjustment and optimization of Guangdong's economic and social structure. Guangdong's economic and social development is standing at a new historical starting point, from manufacturing to promotion to promote a new round of development. This paper will discuss the role of the virtual reality industry in the Guangdong economy and the development of the industry. Methods Based on previous research papers, government work reports, books and website materials at home and abroad, combined with the author's many years of work experience in the industry. This study aims to explore the impact of the virtual reality industry on the regional economy and the timing of the future virtual reality industry. Results Although the virtual reality (VR&AR) industry is still in its growth stage, Guangdong, as the bridgehead of the Chinese economy, still plays a pivotal role in the virtual reality field. The development of the industrial chain is complete, from hardware to software, from the beginning to the interactive technology, from online to offline experience stores, from large companies to small enterprises, in various industry sectors, forming a closed-loop business model. Conclusion The virtual reality will be prominent and significant in the overall pattern of regional economic development. It is also an important breakthrough for the development of science and technology culture industry. It will play a huge role in education, entertainment, service, medical care, industry and other fields in the future. Serve the people's livelihood and promote the construction of modern civilization.

Performance Analysis of Carbon Black/Carbon-Fiber Double-Layer Spacer Fabric/Epoxy Resin Composite Materials

Pengfei Zhang,Kaichang Kou,Zhifeng Deng,Guanglei Wu 한국섬유공학회 2019 Fibers and polymers Vol.20 No.4

In this paper, the carbon-fiber double-layer spacer fabric (CFDSF) was firstly introduced into epoxy resin (EP) forfabrication of CFDSF/EP composite materials. It is indicated that the introduction of CFDSF can significantly improve themechanical properties of EP. Meanwhile, the influence of the content of modified carbon black (CB) on the mechanical andelectrical properties of CB/CFDSF/EP composite materials was investigated. The results showed that the flexural strengthand impact strength of the CB/CFDSF/EP composite materials were improved as the modified CB content increased to 3 %. The bending and impact strengths were found to be 123.8 MPa and 15.88 kJ/m2, respectively, owing to a fracture mechanismtransition induced via the addition of modified CB. As the modified CB content increased from 6 % to 15 %, the bending andimpact strengths exhibited a decreasing trend and typical brittle features were evident in the composite. Further, the volumeresistance of the CB/CFDSF/EP composite materials also presented a decreasing trend.

Comparative analyses of a shield building subjected to a large commercial aircraft impact between decoupling method and coupling method

Pengfei Han,Jingbo Liu,Bigang Fei 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.1

Comparative analyses of a shield building subjected to a large commercial aircraft impact betweendecoupling method and coupling method are performed in this paper. The decoupling method isapplying impact force time-history curves on impact area of the shield building to study impact damageeffects on structure. The coupling method is using a model including aircraft and shield building toperform simulation of the entire impact process. Impact force time-history curves of the fuselage, wingand engine and their total impact force time-history curve are obtained by the entire aircraft normallyimpacting the rigid wall. Taking aircraft structure and impact progress into account some loading areasare determined to perform some comparative analyses between decoupling method and couplingmethod, the calculation results including displacement, plastic strain of concrete and stress of steel platein impact area are given. If the loading area is determined unreasonably, it will be difficult to assessimpact damage of impact area even though the accurate impact force of each part of aircraft obtainedalready. The coupling method presented at last in this paper can more reasonably evaluate the dynamicresponse of the shield building than the decoupling methods used in the current nuclear engineeringdesign

Experimental study on heat transfer characteristics of supercritical carbon dioxide natural circulation

Pengfei Wang,Peng Ding,Wenhuai Li,Rongshun Xie,Chengjie Duan,Gang Hong,Yaoli Zhang 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.3

An experimental study has been conducted to investigate the heat transfer characteristics of supercriticalcarbon dioxide (sCO2) uniformly heated in the horizontal circular smooth tube. The results illustratedthat there was a significant difference in heat transfer between the top wall and bottom wall due to thebuoyancy. Bulk flow acceleration cannot be negligible in the high heat flux region, which leads to heattransfer deterioration. A new heat transfer correlation is proposed, in which the buoyancy parameter andbulk flow acceleration have been taken into account. The new correlation and six classic correlations forsCO2 are examined in horizontal tubes. The comparison indicates that the new correlation has a betterperformance for sCO2 flowing through a horizontal heating tube under natural circulation conditions. Forexample, 94.9% of the calculated results using the new heat transfer correlation were within ±30% of theexperimental results while only 87.9% of that using the Jackson correlation (the best of the six) werewithin the same error bands.