Table of Content

28 February 2014, Volume 48 Issue 02 Previous Issue    Next Issue

Bilogical Science

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Functional Analysis of Lincomycin Transporter Gene lmrC in Streptomyces Lincolnensis LC-G XU Jingjing1,WU Hang1,MENG Sitong2,LIU Ruihua3 HUANG Xunduan1,ZHANG Buchang1,BAI Linquan2 2014, 48 (02):  159-163.  Abstract ( 1298 )   Save To investigate the role of  lincomycin transporter LmrC in lincomycin biosynthesis, lmrC was deleted in a lincomycin high-yielding strain LC-G by homologous recombination. HPLC analysis and resistance assay indicated that lincomycin production and self-resistance in XJJ7, and the lmrC mutant were decreased by 55% and 50%, respectively. Quantitative real-time polymerase chain reaction(PCR) analysis showed that the transcriptional levels of structure genes lmbA and lmbR were drastically reduced, whereas the expression of a regulatory gene lmbU did not change in XJJ7. Moreover, overexpression of lmrC in LCG could not increase the lincomycin yield and the expression of lmbA, lmbR and lmbU as well. However, the resistance to lincomycin was improved in the lmrCoverexpressed strain. Therefore, lmrC was proved to be involved in lincomycin biosynthesis by affecting the transcription of structure genes and confer lincomycin resistance to Streptomyces lincolnensis.  References | Related Articles | Metrics

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Visual Prosthetic System Modeling and Visual Information Processing XIA Penga，HU Jiea，QI Jina，CHAI Xinyub，PENG Yinhonga 2014, 48 (02):  164-167.  Abstract ( 907 )   Save The conflict between the complex scene images of objective world and a limited array of micro-motor stimulation is a problem for visual prosthesis. Starting from the needs of visual information a visual prosthetic device modeling and visual information research was conducted. The visual prosthetic eye movement device was as a biological, mechanical, electronic integrated model, and  the psychophysical experiment  was conducted to assess the work. The results reflect the visual effects and minimum visual information needs.   References | Related Articles | Metrics

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Rectal Perception Function Rebuilding Based on Support  Vector Machine Optimized by Particle Swarm Optimization JIANG Enyu1,2,ZAN Peng1,ZHU Xiaojin1,SHAO Yong1 2014, 48 (02):  168-172.  Abstract ( 860 )   Save Particle swarm optimization (PSO) optimized support vector machine (SVM) based rectal perception function rebuilding method was proposed for rectal perception loss caused by anal incontinence. By analyzing human rectum characteristics, highamplitude propagated contractions (HAPC) in rectal contractions were used to indicate an urge to defecate. Rectal pressure feature was extracted using wavelet packet analysis, taking normalized of wavelet packet coefficients mean and energy as feature vector. Rectal perception prediction model was trained based on SVM whose parameters are optimized by PSO. Then the trained model was used to predict the urge to defecate. And the prediction accuracy of the optimized and nonoptimized SVM with different kernel functions was compared. Experimental results show that the proposed method is effective in rebuilding patients’ rectal perception function.   References | Related Articles | Metrics

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Jacobian Matrix and Kinematic Dexterity Analysis of Human Upper Limb Motion LI Jianfeng1,YUAN Shuzheng1,FAN Jinhong1,TAO Chunjing2,MA Chunmin1,JI Run2 2014, 48 (02):  173-180.  Abstract ( 1224 )   Save In order to understand the kinematic characteristics and manipulation ability of human upper limb, a kinematic model of the right upper limb was built according to limb’s anatomical structure analysis and upper limb motion description method proposed by the International Society of Biomechanics. In this model, the motions of sternoclavicular joint, glenohumeral joint as well as elbow joint were involved, and the motions of acromioclavicular joint and scapulothoraci joint were equivalently replaced by the motion of shoulder gridle. Based on the motion coupling of upper limb joints, the Jacobian matrix describing the velocity relationship between limb joints and limb wrist point was derived, and the kinematic dexterity of the right upper limb moving in coronal plane, sagittal plane and horizontal plane were analyzed. The results show that the number of independent joint parameters which impact wrist point movement is less than that of the natural axes of the upper limb, and the velocity Jacobian matrix has three different structures corresponding to the value region changing of elevation angle; When the upper limb moves in these three special planes, the dexterity index values of extension configurations of the upper limb are smaller than those of inflexion configurations, and human upper limb obtains better kinematic dexterity.   References | Related Articles | Metrics

Bilogical Science

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Design and Evaluation of a Novel Unloading Knee Brace XU Mingfeng,ZHU Liangfan,ZHOU Wenxuan,LUO Yun 2014, 48 (02):  181-186.  Abstract ( 749 )   Save A novel way to reduce internal knee force was proposed by pulling the knee when it is extending after analyzing the current working principle of knee brace, and a concrete design with detailed kinematic and mechanical analysis was put forward. Then its effect on people was evaluated generally by the experiment which built the relationships between pressures, shears force and skin deformation range of thigh and proved the effectiveness of the mechanism. Key words： References | Related Articles | Metrics

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Design of Tissue Compression Cavity Unit with Negative Stiffness  for Shape Variable Prosthesis Socket   GAN Yun，LI Xiang，SANG Yuanjun，WANG Minghui，LUO Yun 2014, 48 (02):  187-192.  Abstract ( 873 )   Save Aimed at the contradiction between the function transit and safety of functional prosthesis，a timeshared load-bearing interface with shape variable socket for functional prosthesis was proposed, which can solve the problems resulted from longtime overload, such as ischemic tissue necrosis. Compression cavity units with negative stiffness were designed to clamp the soft tissue of the body by making the cavity unit to contract. Negative stiffness of variable cavity unit makes it easier to adjust the tightness of soft tissue compression and provides the socket with the function of overload protection. The experiment has proved that the design is feasible.   References | Related Articles | Metrics

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In Vivo Research of Performance and Biocompatibility of an Artificial Anal Sphincter KE Lei1,YAN Guozheng1,LIU Zhiqiang1,YAN Sheng1,WANG Zhiwu1,WANG Yongbing2 2014, 48 (02):  193-198.  Abstract ( 964 )   Save To evaluate the biocompatibility and performance of the optimized artificial anal sphincter system, an in vivo experiment was designed. Blood was collected from the Beagle dogs’ jugular vein on days 1 and 4; at weeks 1, 2, 4 and 5, postoperatively. Biochemical parameters including total protein, albumin, total bilirubin, aspartate aminotransferase, blood urea nitrogen, creatinine, and Creactive protein were examined. The total bilirubin levels remained within the normal range, and the time courses of aspartate aminotransferase of the two Beagle dogs were within the baseline levels after 2 weeks of implantation, demonstrating no liver function complications. The blood urea nitrogen and creatinine levels remained within the normal range, indicating no renal function complications. The total protein and albumin fluctuated within the normal range throughout the duration of this study. The level of Creactive protein did not increase and no infection and inflammation were found. The experimental data indicated that the artificial anal sphincter system demonstrated no adverse influence on blood serum chemistry and exhibited an effective system performance.   References | Related Articles | Metrics

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Electrochemically Synthesized PANI-MnO2 Coatings and Their Effect on Interface Properties of Neural Microelectrode ZHANG Wenguang,WU Dongdong，LI Zhengwei,LUO Yun 2014, 48 (02):  199-204.  Abstract ( 804 )   Save In this paper, a simple and low-cost method for improving the performance of neural microelectrodes was reported. The electrochemical polymerization of conducting polymer PANI and PANI-MnO2 were performed to modify the surface of the microelectrode sites, and the morphology and electrical properties of the coated microelectrodes were investigated to analysize the influence of MnO2 doping on the PANI coating. The result showed that the surface morphology of the PANI coating was improved by MnO2 doping. Compared to the electrode with PANI, the charge injection capacity of the electrode with PANI-MnO2 increased by about 7 fold and the impedance decreased to the original 1/6 (@ 1 kHz). The electrical properties was more stable and excellent with PANI-MnO2 coating. References | Related Articles | Metrics

Atomic Energy Technology

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Impacts of Tube Support Plate on Flow and Heat Transfer Characteristics of Steam Generator   YANG Yuanlong1,2,SUN Baozhi2，ZHANG Guolei2，ZHANG Peng2 2014, 48 (02):  205-209.  Abstract ( 926 )   Save Based on the similarity principle, a three-dimensional “unit pipe” physical model of a steam generator coupled quatrefoil tube support plate was established. A numerical study of the impacts of tube support plate on steam generator flow and heat transfer characteristics was performed by using the fluidsolid coupled methodology and thermal phase change model based on boundary conditions where the secondary side fluid run into the hot leg and cold leg by a distribution ratio of 4∶1. Simulation results show that balanced boiling distributions in the hot leg and cold leg are obtained and the calculated steam quality of the outlet agrees well with the operating parameter of the steam generator at the Daya Bay Nuclear Power Plant. Due to the smaller area of the flow crosssection of the tube support plate, the secondary fluid velocity, surface heat transfer coefficient and steam quality sharply increases and then decreases in the support regions, respectively. The recirculation behavior appears at the top of the support plate, which increases the possibility of deposit of particles and tube corrosion. This numerical simulation methodology can provide technical support for the optimization of the structural design of steam generator tube support plate. References | Related Articles | Metrics

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Abnormal Parameter Reconstruction for Marine Nuclear Power Plant Based on MultiSignal Coupling WANG Xiaolong,CAI Qi,CHEN Yuqing 2014, 48 (02):  210-213.  Abstract ( 1036 )   Save Because of the harsh environment of operating conditions of marine nuclear power plant, some parameters was often lost due to failures of measuring instrument and measurement of transmission channel, which influenced the operator’s judgement about the running states of the system and further jeopardize the operation safety of the system. Therefore, this paper put forward a reconstruction method based on multisignal coupling. This method reconstructed the lost signals with a reconstruction data model designed according to the strong coupling of important parameter and the running historical data of nuclear power plant by the method of artificial intelligence and data statistics. Tests show that this method can reconstruct the lost signal fast and efficiently in normal operation transient conditions of nuclear power plant, and is fit for being used online.   References | Related Articles | Metrics

Aeronautics & Astronautics

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Flow Control on High-Lift Devices ZHOU Tao，LI Yalin，CHEN Yingchun 2014, 48 (02):  215-221.  Abstract ( 971 )   Save In this paper, many kinds of flow control is introduced from the working principle, lift enhancing efficiency and the application. The flow control includes vortex generators on flap, spoiler deflection, ZHU’s flap, self-activated movable flap, zero mass actuation, plasma actuators, dynamical lift enhancing, and so on. The analysis results indicate that, these flow control technique has great potential for improving the lift enhancing efficiency of civil aircraft.   References | Related Articles | Metrics

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Design and Optimization of Boundary Layer Suction Configurations Within a Highly-Loaded Diffusion Stator YU Rui，QIANG Xiaoqing，TENG Jinfang，DU Zhaohui 2014, 48 (02):  222-228.  Abstract ( 686 )   Save The design and optimization of 2D and 3D boundary layer suction (BLS) configurations within a highly-loaded diffusion stator was conducted in this paper by using numerical simulations. A detailed analysis was done based on flow mechanism to reveal the reason for reducing flow separation and improving compressor performance by BLS method. The numerical results show that the best BLS position is located at the region a little backward from the separation point in 2D cascade. Further discussion on 3D BLS shows that the combination of blade suction slots along the whole span and slots along streamline at the hub-suction side region achieves the best effect. This compound BLS configuration can effectively control the strong 3D separation flow at the hub-suction side region, which improves the flow condition and leads to a better stage performance. Key words： References | Related Articles | Metrics

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Relative Navigation for Spacecraft Formation Based on Simplified Divided Difference Filter LI Wei,LIU Meihong,DUAN Dengping 2014, 48 (02):  229-233.  Abstract ( 159 )   Save A simplified version of the nonlinear divided difference filter (DDF) algorithm based on Stirling’s interpolation formula called simplified divided difference filter (SDDF) was applied to relative navigation for spacecraft formation, using a limited divided difference items of the Taylor’s expansions as an approximation to the real nonlinear system equations. Numerical simulation results indicate that the SDDF filter algorithm has the obvious advantages than that of the EKF, including the higher navigation precision, faster convergence and better stability; the accuracy improvement of the SDDF compared with the EKF are 79% and 52% for relative position and velocity. This algorithm can be applied to relative navigation for spacecraft formation flying and is worthy of application. Key words： References | Related Articles | Metrics

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Dry and Wet Modal Analysis and Evaluation of Influencing Factors for Flexible Airship Envelop CHEN Yufeng,CHEN Wujun,HE Yanli,ZHANG Daxu 2014, 48 (02):  234-238.  Abstract ( 162 )   Save In order to grasp the unconstrained modal characteristics of the flexible airship envelop, the natural vibration performance was investigated thoroughly for a 25 m long stratospheric demonstration airship. The flexible airship envelop features is a freefloating inflatable membrane structure. Based on the mechanical nature of pneumaticstressed membrane structures, the deformed equilibrium shape and stress were computed from the initial geometry configuration, subjected the inflated air pressure through nonlinear structural analysis. The block Lanczos method was employed for modal analysis. The main influencing factors were evaluated thoroughly for modal behavior, including shell element and membrane element, pressure, geometry size, weld seam, nonuniform distributed mass and the added atmosphere mass. The numerical models of membrane and shell element have close natural frequency and identical modal shape. The airadded mass, pressure and geometry size are the key factors to govern the modal performance. This paper can provide reference for structural engineering design of stratospheric airship.   References | Related Articles | Metrics

Mathematical sciences and chemical

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Droplet Dynamics on Surfaces with Non-Uniform Wettability GONG Shuai,CHENG Ping 2014, 48 (02):  239-244.  Abstract ( 78 )   Save Three-dimensional droplet dynamics on surfaces with non-uniform wettability were investigated based on an improved lattice Boltzmann method (LBM) for multiphase flows. Both the accuracy and numerical stability were improved in this model. Droplet spreading and movement on surfaces with non-uniform wettability was analyzed. The mechanism of droplet movement and splitting under the action of wettability gradient was illustrated based on the analysis of velocity field during the droplet splitting process. References | Related Articles | Metrics

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Detached Eddy Simulation of Electromagnetic Control of Three-Dimensional Flow Around a Circular Cylinder YIN Jifu,YOU Yunxiang,LI Wei,HU Tianqun 2014, 48 (02):  244-251.  Abstract ( 168 )   Save The distribution of the electromagnetic force around a cylinder covered by electromagnetic actuators was obtained by solving the Maxwell equation system, and such an electromagnetic force was added to the momentum equation of the flow governing equation system. The detached eddy simulation (DES) method was adopted to simulate and analyze the flow characteristics around a circular cylinder and its lift/drag characteristics in a weakly conductive fluid at Reynolds number Re=3 900. Results show that the electromagnetic force can increase the fluid kinetic energy near the cylinder wall, delay flow separation and weaken the flow threedimensional effect, as well as the jet phenomenon produces after the electromagnetic force parameter reaches some certain critical value. Moreover, the total and pressure difference drags decrease with the increase of the electromagnetic force parameter; however the friction increases, and the electromagnetic force can significantly reduce the lift fluctuation amplitudes.   References | Related Articles | Metrics

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Two-Degree-of-Freedom Flow-Induced Vibration of an Isolated Cylinder Structure in Planar Shear Flow TU Jiahuang，ZHOU Dai，MA Jin，LU Jiabao 2014, 48 (02):  252-259.  Abstract ( 92 )   Save Based on the four-step semi-implicit Characteristic-Based-Split (CBS) stabilized fluid finite element method, the flow-induced vibration of an elastically supported cylinder with two degrees of freedom in 2D planar shear flow was numerically studied. Besides, the effects of some key parameters, such as natural frequency ratio(r), shear ratio(k) and reduced velocity(ur), on vibration response of the cylinder and fluid field around it were analyzed. The results show that the lock-in range and resonant region of the cylinder broaden as k increases. The reduced velocity has a great impact on the maximum vibration amplitude of the cylinder: the amplitude is larger in the lock-in range; however, it becomes small in  other cases. It is found that, in the resonant region, the orbital trajectory of the cylinder shows an 8-shaped figure at a larger r, whereas it transfers from the 8-shaped figure motion to a raindrop motion with the increase of k at the lower r. The vortex shedding patterns are 2S and P+S in the shear flow.   References | Related Articles | Metrics

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Force Analysis of Liquid Droplets on Micro-Grooved Surfaces with Air Flow HUANG Suhe,HU Haibao,CHEN Libin,SONG Dong 2014, 48 (02):  260-264.  Abstract ( 83 )   Save The dynamics of a liquid droplet driven by an air flow and displaced on the micro-grooved surface was investigated, and a force balance model in terms of dynamic contact angle was obtained. Two terms of θ(α) and r (α) were improved in the calculation of capillary force. The term θ(α) was expressed by a piecewise function while term r (α) was deduced by the equation of elliptical contact line. The drag force was simplified by importing the no-slip boundary condition. Then the model was tested in a wind tunnel experimentally. The test results turned out to be consistent with the experimental results, which proved that the force balance model was rational and effective. References | Related Articles | Metrics

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Method of Numerical General Solution for Inverse Line Heat Source Problem in Steady State JIANG Lanfanga,LIU Hongb，CHAI Guozhongb,YANG Youdonga，ZHU Jionglinb 2014, 48 (02):  265-270.  Abstract ( 173 )   Save A method for identification of source terms for inverse heat conduction problems in steady state  was presented. Based on finite element numerical solution, an explicit formula for numerical general solution was constructed, which satisfied the heat conduction governing equations and boundary condition, taking the intensity of heat source as the variable with discrete form. The method converted the heat conduction inverse problem to multivariables limit problem, which made the identification of intensity of heat source easy. The basic computational formula was derived, the mathematics modeling problem of identification of intensity of heat source for inverse heat conduction problems was discussed and  error analysis was conducted. Taking the heat source design of mould heating plate as an example, the correctness and practicability of the algorithm was validated, which is of importance for further investigation of identification of space of heat source and multidimensional source terms for inverse heat conduction problems.   References | Related Articles | Metrics

Mechanical instrumentation engineering

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Dynamic Behavior of a Rotating Shaft Immersed in a Fluid Annulus CHENG Dea,YAO Zhenqianga,b,XUE Yaboa,SHEN Honga,b 2014, 48 (02):  271-276.  Abstract ( 120 )   Save To investigate the influence of annular flow on the dynamic behavior of the rotor, partial differential equations are established to describe the flow in the annulus according to the continuum theory and momentum theorem. The linear perturbation method was used to separate the steadystate part and the dynamic part of the flow field pressure in the annulus. The expression of the dynamic force generated by the annular flow was calculated. A test rig was built to validate the theoretical model. The dynamic model of the dry rotor in the test rig was established using the finite element method. The modal frequency of the rotor tested in the test rig was used to determine the contact stiffness of the flange in the rotor, and then the theoretical model was demarcated. The dynamic force of the annular flow can be expressed by combination of the mass matrix, damping matrix and stiffness matrix. The dry rotor model integrated with the dynamic force becomes the wet rotor model. The variation of the modal frequency and system damping of the wet rotor corresponding to the rotor speed were calculated. The theoretical results were validated by experimental results. The research shows that the annular flow can reduce the modal frequency and can induce the instability of the rotor in some speed domain. References | Related Articles | Metrics

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Combined Incentive Mechanism Based on Trade Credit in a Supply Chain with Reordering Opportunities ZENG Shunqiu1,2,LUO Jianwen2 2014, 48 (02):  277-281.  Abstract ( 117 )   Save Based on a twolevel supply chain with reordering opportunities under advertising dependent random demand, this paper compared the supply chain members’ optimal policies between centralized and decentralized decision-making systems. The comparsion shows that it is very difficult for a single advertising subsidy mechanism to realize perfect coordination of the decentralized supply chain. Therefore, through the combined incentive mechanism which consists of trade credit and advertising subsidy, the manufacturer could induce the retailer to choose the optimal ordering quantity and advertising investment for the centralized system, and further achieve the Pareto improvement of the manufacturer’s and retailer’s expected profits. Finally, this paper proposed a numerical example to verify the main conclusions, and to illustrate the effect of adjusting the relevant parameter on optimal policies and the splitting of expected profits of supply chain.   References | Related Articles | Metrics

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Premiums and Discounts on ETFs and Their Volatilities in Chinese Markets CAO Zhiguang 2014, 48 (02):  282-289.  Abstract ( 87 )   Save The discount behavior and volatility on exchange-traded funds (ETFs) trading in Chinese markets  were investigated from both theoretical and empirical perspectives. A theoretical model with heterogeneous beliefs and short-sale constraints was established to explain discounts on ETFs and their volatilities. The theoretical model conjures that ETFs in Chinese markets are more likely to trade at a discount relative to western developed markets and the volatility of an ETF is greater than that of its NAV. In addition, empirical results based on daily data from February, 2005 to December, 2012 validates the theory proposed. References | Related Articles | Metrics

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Dual-Channel Supply Chain Joint Inventory Model Under Stochastic Demand LIU Zheng1,XU Qi1，Tang Bingyong 1，ZHOU Min2 2014, 48 (02):  290-299.  Abstract ( 143 )   Save The competition and cooperation of dual-channel supply chain tend to increase the demand uncertainty. By consideration of random demand fluctuations, the base stock model and stock-out model of manufacturer and retailer under independent and joint inventory decision modes of two-stage dualchannel supply chain were explored. By simulation and comparison of the two models, the effect of stock-out cost, demand fluctuations on base stock level, existing stock level as well as other indicators were analyzed, and  two modes of inventory costs were studied. It is proved that the joint inventory strategy is superior to independent joint inventory strategy due to reduction of respective cost as well as overall supply chain cost. Therefore, the joint stock inventory strategy of dualchannel supply chain can share stock and coordinate stock level, reduce risk of stock-out and finally significantly minimize supply chain cost. References | Related Articles | Metrics

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Pricing Strategies of eWOM Virtual Communities LU Xiaojing,CHEN Hongmin 2014, 48 (02):  300-305.  Abstract ( 131 )   Save Based on theory of two-sided market, this paper discussed the impact of self network externalities and across network externalities between users of two sides on the pricing strategy of eWOM virtual communities. Additionally, the  quality of merchants was considered and explored. The results show that the of the  optimal price platform for consumers rises with the augment of  self network externalities of consumers and the percentage of merchants with high quality, and declines with the augment of across network externalities of consumers to merchants. The  optimal price of the platform for merchants rises with the augment of  across network externalities of machant to consumers. And the price elasticity of the demand of merchants with high quality is smaller than that of merchants with low quality.   References | Related Articles | Metrics

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Pricing and Ordering Strategies for Fresh Products with Different Quality Levels TIAN Zhongweia,DONG Mingb 2014, 48 (02):  306-311.  Abstract ( 130 )   Save Fresh products, which may deteriorate during the distribution process, are usually divided into different quality levels. The retailer faces two different selling strategies, i.e., separate selling strategy and mixed selling strategy. This paper studied the optimal pricing and ordering strategies for a retailer of fresh products under these two different selling strategies. Specifically, a two-period model was considered in this paper. Through numerical analysis, it explored the effects of market demand volatility, product quality difference and freshness keeping ratio on the retailer’s optimal decisions and profit under different selling strategies. References | Related Articles | Metrics

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Revenue-Sharing Contract Design in a Supply Chain Based on Capacity Investments   ZHU Chenhuia，DONG Mingb,LIU Shaoxuanb 2014, 48 (02):  312-316.  Abstract ( 128 )   Save Companies often face significant technical and financial risks when building new factories to expand capacity. Coordination of supply chain members in capacity investments can reduce risk. This paper considered a supply chain which consisted of one supplier and two manufacturers. One of the manufacturers provided capacity investment for the upstream supplier. In return, the supplier shared some portion of its revenue with the manufacturer. This paper studied the optimal contract designs under different modes of collaboration between the manufacturer and the supplier. It analyzed the effect of optimal contracts on optimal decisions of supply chain members and on their respective profits. It obtained several insights through numerical simulations which were useful in actual negotiation. References | Related Articles | Metrics