针对核医学发展需求,本研究提出将直线加速器机房改建为回旋加速器机房的解决方案。通过理论计算与MCNP(Monte Carlo N-particle transport code)模拟,评估原重混凝土机房(厚度1.2~2.6 m)对γ射线的屏蔽效能,并针对中子辐射提出内壁增...针对核医学发展需求,本研究提出将直线加速器机房改建为回旋加速器机房的解决方案。通过理论计算与MCNP(Monte Carlo N-particle transport code)模拟,评估原重混凝土机房(厚度1.2~2.6 m)对γ射线的屏蔽效能,并针对中子辐射提出内壁增设含硼聚乙烯(24~48 cm)的优化方案。结果表明:原有混凝土结构满足γ防护要求,选择屏蔽中子效率高、次生γ增量少的含硼聚乙烯,经模拟验证剂量率水平较低;采用聚乙烯慢化层与含硼聚乙烯(11%)吸收层组合,有效避免铁矿石骨料的中子活化风险;该方案施工难度低,成本可控,能够实现医疗设施高效再利用。本研究为同类改造提供技术参考,符合我国核医学高质量发展政策需求。展开更多
[Objective]This study aimed to improve the yield of bacteriocins from lactic acid bacteria by optimizing the fermentation process for production of bacteriocins from lactic acid bacteria.[Method]By single-factor analy...[Objective]This study aimed to improve the yield of bacteriocins from lactic acid bacteria by optimizing the fermentation process for production of bacteriocins from lactic acid bacteria.[Method]By single-factor analysis,fermentation temperature,seed age,inoculation volume,fermentation duration and fermentation media p H were optimized to determine the best fermentation process.The inhibitory zone of bacteriocins from lactic acid bacteria was analyzed with oxford cup method,based on which the fermentation process was evaluated.[Result]The optimal fermentation process was optimized：fermentation temperature 37℃,seed age 14 h,inoculation volume 2%,fermentation duration 48 h,fermentation media p H 5.0.[Conclusion]Under the optimized fermentation conditions,the yield of bacteriocins from lactic acid bacteria was improved significantly.展开更多
In order to reduce the cost of ABs-type hydrogen storage alloys, effects of substitution of Ce for La （A side） and Fe, Mn, Al for Ni （B side） on structural and electrochemical properties of （LaCe）;（NiFeMnAl）s ...In order to reduce the cost of ABs-type hydrogen storage alloys, effects of substitution of Ce for La （A side） and Fe, Mn, Al for Ni （B side） on structural and electrochemical properties of （LaCe）;（NiFeMnAl）s alloys were studied systematically. To make component uniform and operation easy, uniform design （UD） method was introduced into the study of composition optimization of Co-free Fe-containing ABs-type alloys for the first time. X-ray diffraction （XRD） results showed that the designed alloys were of single CaCus-type structure phase. The replacement of Fe had a severe effect on electrochemical capacity, and the substitution of Fe and A1 had a synergetic action among the unit cell volume, cycling stability and high rate discharge property. Interestingly, it was found that the hydrogen storage alloys with excessively high plateau pressure showed a tilted line in Nyquist plot instead of the semicircle, and the current decayed rapidly to near zero at the beginning of the step in constant potential step （CPS）, indicating that electrochemical impedance spectra （EIS） and CPS cannot accurately measure the electrochemical kinetics process of the hydrogen storage alloys with excessively high plateau pressure.展开更多
A fuzzy optimization model of storage space allocation is proposed,and a rolling-planning method is derived. The model takes the uncertainty of departure time of import containers and arrival time of export containers...A fuzzy optimization model of storage space allocation is proposed,and a rolling-planning method is derived. The model takes the uncertainty of departure time of import containers and arrival time of export containers into account. For each planning horizon,the problem is decomposed into two levels: the first level minimizes the unbalanced workloads among blocks using hybrid intelligence algorithm;based on block workloads allocated in the above level,the second level minimizes the number of blocks to which the same group of import containers are split. Numerical results show that the model reduces workload imbalance,and speeds up the vessel loading and discharging process.展开更多
In this paper, a numerical method for solving the optimal control （OC） problems is presented. The method is enlightened by the Chebyshev-Legendre （CL） method for solving the partial differential equations （PDEs）...In this paper, a numerical method for solving the optimal control （OC） problems is presented. The method is enlightened by the Chebyshev-Legendre （CL） method for solving the partial differential equations （PDEs）. The Legendre expansions are used to approximate both the control and the state functions. The constraints are discretized over the Chebyshev-Gauss-Lobatto （CGL） collocation points. A Legendre technique is used to approximate the integral involved in the performance index. The OC problem is changed into an equivalent nonlinear programming problem which is directly solved. The fast Legendre transform is employed to reduce the computation time. Several further illustrative examples demonstrate the efficiency of the proposed method.展开更多
Considering the interaction between the berth and the yard,this paper studies the collaborative optimization problem of berth allocation and yard storage from the point of the ships over a certain planning period.This...Considering the interaction between the berth and the yard,this paper studies the collaborative optimization problem of berth allocation and yard storage from the point of the ships over a certain planning period.This collaborative optimization problem is formulated as the integer programming,which aims at minimizing the total truck travel distance.And decision variables are the berthing positions for visiting ships and the storage positions for export containers.Meanwhile,this paper demonstrates the complexity of the problem in theory.And the hybrid tabu genetic algorithm is designed to solve the problem to obtain the optimal berth allocation position and export container storage position.For this algorithm,the rule is applied to generate the initial feasible solutions,and the crossover and mutation operation are simultaneously applied to optimize the initial solutions.Finally,this paper discusses two different scenes:the same berth scene and the same ship scene.The influence of two different scenes on truck travel distance is analyzed by different numerical examples.Numerical examples’results show that the collaborative optimization of berth allocation and yard storage can effectively shorten the truck travel distance and improve the efficiency of terminal operation,which provides the decision support for terminal operators.展开更多
文摘针对核医学发展需求,本研究提出将直线加速器机房改建为回旋加速器机房的解决方案。通过理论计算与MCNP(Monte Carlo N-particle transport code)模拟,评估原重混凝土机房(厚度1.2~2.6 m)对γ射线的屏蔽效能,并针对中子辐射提出内壁增设含硼聚乙烯(24~48 cm)的优化方案。结果表明:原有混凝土结构满足γ防护要求,选择屏蔽中子效率高、次生γ增量少的含硼聚乙烯,经模拟验证剂量率水平较低;采用聚乙烯慢化层与含硼聚乙烯(11%)吸收层组合,有效避免铁矿石骨料的中子活化风险;该方案施工难度低,成本可控,能够实现医疗设施高效再利用。本研究为同类改造提供技术参考,符合我国核医学高质量发展政策需求。
基金Supported by Research Project of Sichuan University of Science&Engineering(No.2011RC12,2014KY02)Scientific Research Foundation of the Education Department of Sichuan Province(No.15ZA0222)Research Project of Liquor-marking Biological Technology and Application of Key Laboratory of Sichuan Province(NJ2013-06)
文摘[Objective]This study aimed to improve the yield of bacteriocins from lactic acid bacteria by optimizing the fermentation process for production of bacteriocins from lactic acid bacteria.[Method]By single-factor analysis,fermentation temperature,seed age,inoculation volume,fermentation duration and fermentation media p H were optimized to determine the best fermentation process.The inhibitory zone of bacteriocins from lactic acid bacteria was analyzed with oxford cup method,based on which the fermentation process was evaluated.[Result]The optimal fermentation process was optimized：fermentation temperature 37℃,seed age 14 h,inoculation volume 2%,fermentation duration 48 h,fermentation media p H 5.0.[Conclusion]Under the optimized fermentation conditions,the yield of bacteriocins from lactic acid bacteria was improved significantly.
基金Project supported by the Guangdong-Ministry of Education (GD-MOE) Coordination Project of Industry Academic and Research (2008B090500274)Chengdu Key Technologies R&D Program (10GGYB897GX-023)
文摘In order to reduce the cost of ABs-type hydrogen storage alloys, effects of substitution of Ce for La （A side） and Fe, Mn, Al for Ni （B side） on structural and electrochemical properties of （LaCe）;（NiFeMnAl）s alloys were studied systematically. To make component uniform and operation easy, uniform design （UD） method was introduced into the study of composition optimization of Co-free Fe-containing ABs-type alloys for the first time. X-ray diffraction （XRD） results showed that the designed alloys were of single CaCus-type structure phase. The replacement of Fe had a severe effect on electrochemical capacity, and the substitution of Fe and A1 had a synergetic action among the unit cell volume, cycling stability and high rate discharge property. Interestingly, it was found that the hydrogen storage alloys with excessively high plateau pressure showed a tilted line in Nyquist plot instead of the semicircle, and the current decayed rapidly to near zero at the beginning of the step in constant potential step （CPS）, indicating that electrochemical impedance spectra （EIS） and CPS cannot accurately measure the electrochemical kinetics process of the hydrogen storage alloys with excessively high plateau pressure.
基金the Specialized Research Fund for the Doctoral Program of Higher Education (No. 200801411105)
文摘A fuzzy optimization model of storage space allocation is proposed,and a rolling-planning method is derived. The model takes the uncertainty of departure time of import containers and arrival time of export containers into account. For each planning horizon,the problem is decomposed into two levels: the first level minimizes the unbalanced workloads among blocks using hybrid intelligence algorithm;based on block workloads allocated in the above level,the second level minimizes the number of blocks to which the same group of import containers are split. Numerical results show that the model reduces workload imbalance,and speeds up the vessel loading and discharging process.
基金supported by the National Natural Science Foundation of China (Grant Nos.10471089,60874039)the Shanghai Leading Academic Discipline Project (Grant No.J50101)
文摘In this paper, a numerical method for solving the optimal control （OC） problems is presented. The method is enlightened by the Chebyshev-Legendre （CL） method for solving the partial differential equations （PDEs）. The Legendre expansions are used to approximate both the control and the state functions. The constraints are discretized over the Chebyshev-Gauss-Lobatto （CGL） collocation points. A Legendre technique is used to approximate the integral involved in the performance index. The OC problem is changed into an equivalent nonlinear programming problem which is directly solved. The fast Legendre transform is employed to reduce the computation time. Several further illustrative examples demonstrate the efficiency of the proposed method.
文摘Considering the interaction between the berth and the yard,this paper studies the collaborative optimization problem of berth allocation and yard storage from the point of the ships over a certain planning period.This collaborative optimization problem is formulated as the integer programming,which aims at minimizing the total truck travel distance.And decision variables are the berthing positions for visiting ships and the storage positions for export containers.Meanwhile,this paper demonstrates the complexity of the problem in theory.And the hybrid tabu genetic algorithm is designed to solve the problem to obtain the optimal berth allocation position and export container storage position.For this algorithm,the rule is applied to generate the initial feasible solutions,and the crossover and mutation operation are simultaneously applied to optimize the initial solutions.Finally,this paper discusses two different scenes:the same berth scene and the same ship scene.The influence of two different scenes on truck travel distance is analyzed by different numerical examples.Numerical examples’results show that the collaborative optimization of berth allocation and yard storage can effectively shorten the truck travel distance and improve the efficiency of terminal operation,which provides the decision support for terminal operators.
