Qiongfang Zeng

The present study investigated the difference in transmittance of light carrying opposite spin angular momentum (SAM) and orbital angular momentum (OAM) through chlorella algal fluid with varying concentrations and thicknesses. Our results indicate that, under specific conditions, right-handed light sources exhibit higher transmittance in the algal fluid compared to left-handed light sources. Furthermore, we observed that light with OAM also demonstrated higher transmittance than other types of light sources, leading to faster cell density growth of Chlorella. Interestingly, we also discovered that light with OAM stimulates Chlorella to synthesize more proteins. These findings provide different insights for selecting appropriate light sources for large-scale algae cultivation, and may facilitate the realization of carbon peaking and carbon neutrality in the future.

Busy, complex railway stations that serve as origin and termination points for a significant proportion of trains are essential to regional railway networks. Resolving conflicts between arrival–departure operations and shunting operations of cross-line trains and originating or terminating passenger trains in the throat area is important for safety in these multidirectional stations. The main task of this paper is to study the train platforming problem, and we consider the integration of track and route allocation with shunting route allocation on the basis of the traditional TTP problem, so as to formulate a strong anti-interference track allocation plan for busy, complex railway stations. Therefore, in view of the complex characteristics of train operation in busy, complex railway stations, we extensively examine the technical operational characteristics of various trains in multidirectional stations, which are the key constraints of the model, and establish a mixed-integer linear programming model. This model aims to balance the buffer time for track occupation and optimize the routing and scheduling of trains in stations. Furthermore, an improved genetic algorithm is proposed to effectively implement the developed model. In the case study of Guangzhou Station, the occupation analysis after the optimization of the method in this paper indicates that the shunting operations significantly interfere with arrival–departure operations in throat areas. The optimization of buffer times and track utilization times resulted in notable reductions of 30.55% and 77.82%, respectively, in quadratic differences. These outcomes provide empirical evidence supporting the feasibility of the proposed model and algorithm for addressing train platforming problems, particularly in complex, multidirectional, and heavily trafficked railway stations.

Track failure at a railway station is a common disruption in the station area caused by abnormal weather or frequent use. This paper focuses on the real-time track reallocation problem to recover the affected track utilization plan and minimize the total train delays and passenger inconveniences. Train platforming operations in busy complex passenger stations are generally conducted according to fixed track utilization rules. In this paper, we presented a mixed-integer linear programming model for train platforming problems with constraints relevant to fixed track utilization rule and objectives of balanced usage of tracks. Furthermore, we proposed an improved genetic simulated annealing algorithm based on improved crossover and selection methods without breaking the fixed track utilization rule constraint. An experiment of Guanzhou East Station with fixed track utilization rules shows the effectiveness of the proposed model and algorithm. The model and algorithm provide efficient approaches for track reallocation problems based on fixed track utilization rules in busy complex passenger stations.

In this paper, we present a track-circuits-based model for robust train platforming problem (RTPP) at busy complex stations. First, we explicitly explained the operation process of different train types and fixed track utilization rule. Second, we propose a multicriterion scheduling model for RTPP with objectives of minimizing the weighted number of delayed trains, minimizing trains that break rules, and maximizing robustness based on sectional-release interlocking system. Third, we design a hybrid heuristic algorithm to solve the above model based on dispatching rules and present different new solution generation strategies to further optimize rule-based solutions. Performance of the new solution generation strategies and algorithm is evaluated based on a case study for Guangzhou East Station. To validate the effectiveness of robustness indicator, we compared its performance on delay propagation counteraction with a TPP model without robustness objective under the same perturbation scenario.

A polarimeter for optical rotation (OR) detection and optical active media measurement based on m=1 Zero-Order Liquid Crystal Polymer Vortex Half-Wave Retarder (LCPVR) and Digital Image Processing (DIP) was proposed in this letter. In this research, we demonstrate the principle of measuring optical rotation with LCPVR polarimeter system which is based on Jones vectors and matrices. Two opposing wedge-shaped dark areas will appear in the output image when the uniform distribution polarized light passes the LCPVR. DIP is used to find the darkest line in the opposing wedge-shaped dark areas, then the optical rotation angle is calculated, which is from −90 degree to +90 degree. The polarimeter is used to measure the concentration of sucrose solutions at the range of 1000-10000mg/dl L. We also present the fabricated method of LCPVR by Digital Micro-mirror Device (DMD) system, and the LCPVR will be low price in the fabricated processing. Compared with existed polarimeter, our polarimeter with LCPVR has simpler optical structure and less size. The key innovation of this system is that the optical rotation angle can be displayed with visualized image except digital. And the rotation angle is calculated by DIP without mechanical adjust a 1/4 wave plate, which lead to higher detection speed and stronger stability.

Differential pricing of trains with different departure times caters to the taste heterogeneity of the time-dependent (departure time) demand and then improves the ticket revenue of railway enterprises. This paper studies optimal differential pricing for intercity high-speed railway services. The distribution features of the passenger demand regarding departure times are analyzed, and the time-dependent demand is formulated; a passenger assignment method considering departure periods and capacity constraints is constructed to evaluate the prices by simulating the ticket-booking process. Based on these, an optimization model is constructed with the aim of maximizing the ticket revenue and the decision variables for pricing train legs. A modified direct search simulated annealing algorithm is designed to solve the optimization model, and three random generation methods of new solutions are developed to search the solution space efficiently. Experimental analysis containing dozens of trains is performed on Wuhan-Shenzhen high-speed railway in China, and price solutions with different elastic demand coefficients () are compared. The following results are found: (i) the optimization algorithm converges stably and efficiently and (ii) differentiation is shown in the price solutions, and the optimized ticket revenue is influenced greatly by , increasing by 7%–21%.