Iron ore sintering is a pre-treatment technology by which orefines are converted into porous and permeable sin-ters,which are the used in blast furnaces.This process can be adversely affected by air leakage phenomena ...Iron ore sintering is a pre-treatment technology by which orefines are converted into porous and permeable sin-ters,which are the used in blast furnaces.This process can be adversely affected by air leakage phenomena of various types.As experimental measurements are relatively difficult and often scarcely reliable,here a theoretical model based on typicalfluid-dynamic concepts and relationships is elaborated.Through the analysis of two extreme cases,namely,those in which leakage is due to a small hole or a full rupture,a generalized hole-bed mod-el is introduced,which for thefirst time also includes a complete bed permeability equation and can deal with different leakage position conditions.The results show that the model can evaluate the influence of leakage on the system at one time and be used to calculate theflowrate and pressure drop.Notably,the obtained results are within a 15%deviation with respect to available experiment values,used for comparison.展开更多
Bearing pitting,one of the common faults in mechanical systems,is a research hotspot in both academia and industry.Traditional fault diagnosis methods for bearings are based on manual experience with low diagnostic ef...Bearing pitting,one of the common faults in mechanical systems,is a research hotspot in both academia and industry.Traditional fault diagnosis methods for bearings are based on manual experience with low diagnostic efficiency.This study proposes a novel bearing fault diagnosis method based on deep separable convolution and spatial dropout regularization.Deep separable convolution extracts features from the raw bearing vibration signals,during which a 3×1 convolutional kernel with a one-step size selects effective features by adjusting its weights.The similarity pruning process of the channel convolution and point convolution can reduce the number of parameters and calculation quantities by evaluating the size of the weights and removing the feature maps of smaller weights.The spatial dropout regularization method focuses on bearing signal fault features,improving the independence between the bearing signal features and enhancing the robustness of the model.A batch normalization algorithm is added to the convolutional layer for gradient explosion control and network stability improvement.To validate the effectiveness of the proposed method,we collect raw vibration signals from bearings in eight different health states.The experimental results show that the proposed method can effectively distinguish different pitting faults in the bearings with a better accuracy than that of other typical deep learning methods.展开更多
Many ocean transportation hub systems consist of two container ports that share the container handling business in the area. The container flow passing through a port is the main measurement of the port's competitive...Many ocean transportation hub systems consist of two container ports that share the container handling business in the area. The container flow passing through a port is the main measurement of the port's competitiveness. In this paper we adopt a Hotelling model to study the container port competition in a so-called "dual gateway-port system". The system contains two ports and two terminals, one belonging to each port. The two governments in which the two ports are located compete on cargo fees and the two terminals determine service price and service quality. We study two models with different levels of competition between the terminals. In the ftrst model, the two terminals are owned by two different operators and in the second model, the two terminals are centralized under one operator. The second model exists in practice but is not well studied in the literature. We derive the cargo fee, terminal service price, and service quality equilibria for these two models. We investigate the competition outcome sensitivity with a numerical study. The numerical results reveal that governments prefer terminals to compete with each other. If the terminals do not have competitive advantages in their service quality, then terminal centralization brings more profits to the terminal operator than the competition case.展开更多
OBJECTIVE: To screen and summarize evaluation indexes for symptom changes in Chinese medicine(CM).METHODS: A case database was established based on information from subsequent patient visits from the case records of f...OBJECTIVE: To screen and summarize evaluation indexes for symptom changes in Chinese medicine(CM).METHODS: A case database was established based on information from subsequent patient visits from the case records of famous doctors since 1866.Symptom change descriptions in the database were regarded as research materials. The evaluation indexes of the symptom changes were screened and summarized.RESULTS: In total, 243 evaluation indexes for 256symptoms were summarized. Among them, common symptoms were frequency, quantity, degree,mobility, color, and correlation with fatigue.CONCLUSION: There are many aspects to evaluating the changes in a symptom. Some symptoms occur with other simultaneous symptoms. The alleviation or aggravation of simultaneous symptoms could reflect the corresponding changes in a symptom. The changes of inducing factors are important to judging changes in symptoms.展开更多
文摘Iron ore sintering is a pre-treatment technology by which orefines are converted into porous and permeable sin-ters,which are the used in blast furnaces.This process can be adversely affected by air leakage phenomena of various types.As experimental measurements are relatively difficult and often scarcely reliable,here a theoretical model based on typicalfluid-dynamic concepts and relationships is elaborated.Through the analysis of two extreme cases,namely,those in which leakage is due to a small hole or a full rupture,a generalized hole-bed mod-el is introduced,which for thefirst time also includes a complete bed permeability equation and can deal with different leakage position conditions.The results show that the model can evaluate the influence of leakage on the system at one time and be used to calculate theflowrate and pressure drop.Notably,the obtained results are within a 15%deviation with respect to available experiment values,used for comparison.
基金the National Key Research and Development Program of China (No. 2019YFB1704500)the State Ministry of Science and Technology Innovation Fund of China (No. 2018IM030200)+1 种基金the National Natural Foundation of China (No. U1708255)the China Scholarship Council (No. 201906080059)
文摘Bearing pitting,one of the common faults in mechanical systems,is a research hotspot in both academia and industry.Traditional fault diagnosis methods for bearings are based on manual experience with low diagnostic efficiency.This study proposes a novel bearing fault diagnosis method based on deep separable convolution and spatial dropout regularization.Deep separable convolution extracts features from the raw bearing vibration signals,during which a 3×1 convolutional kernel with a one-step size selects effective features by adjusting its weights.The similarity pruning process of the channel convolution and point convolution can reduce the number of parameters and calculation quantities by evaluating the size of the weights and removing the feature maps of smaller weights.The spatial dropout regularization method focuses on bearing signal fault features,improving the independence between the bearing signal features and enhancing the robustness of the model.A batch normalization algorithm is added to the convolutional layer for gradient explosion control and network stability improvement.To validate the effectiveness of the proposed method,we collect raw vibration signals from bearings in eight different health states.The experimental results show that the proposed method can effectively distinguish different pitting faults in the bearings with a better accuracy than that of other typical deep learning methods.
基金The authors appreciate the anonymous referees and the editor for their help to improve the quality of the paper. This paper was partially supported by the National Natural Science Foundation of China, NSFC Nos. 71001073, 71302109, 71471118, the Humanities and Social Sciences Foundation of Ministry of Education of China (No. 14YJC630096), the Distinguished University Young Scholar Program of Guangdong Province (No. Yq2013140), the Fundamental Research Funds for the Central Universities (No. 15JNQM028) and Natural Science Foundation of SZU (Grant Nos. 201422 and 827000074).
文摘Many ocean transportation hub systems consist of two container ports that share the container handling business in the area. The container flow passing through a port is the main measurement of the port's competitiveness. In this paper we adopt a Hotelling model to study the container port competition in a so-called "dual gateway-port system". The system contains two ports and two terminals, one belonging to each port. The two governments in which the two ports are located compete on cargo fees and the two terminals determine service price and service quality. We study two models with different levels of competition between the terminals. In the ftrst model, the two terminals are owned by two different operators and in the second model, the two terminals are centralized under one operator. The second model exists in practice but is not well studied in the literature. We derive the cargo fee, terminal service price, and service quality equilibria for these two models. We investigate the competition outcome sensitivity with a numerical study. The numerical results reveal that governments prefer terminals to compete with each other. If the terminals do not have competitive advantages in their service quality, then terminal centralization brings more profits to the terminal operator than the competition case.
基金Supported by the National Natural Science Foundation of China (the Diagnostic Points of General Syndrome Factors on the Symptomatic Units and their Clinical Characteristics,No.81001500)National Program of Science and Technology Development (the Research on Sweating Pattern Recognition of Chinese Medicine and the Development of High-Precision Detection Device,No.2012 BAI25B07)
文摘OBJECTIVE: To screen and summarize evaluation indexes for symptom changes in Chinese medicine(CM).METHODS: A case database was established based on information from subsequent patient visits from the case records of famous doctors since 1866.Symptom change descriptions in the database were regarded as research materials. The evaluation indexes of the symptom changes were screened and summarized.RESULTS: In total, 243 evaluation indexes for 256symptoms were summarized. Among them, common symptoms were frequency, quantity, degree,mobility, color, and correlation with fatigue.CONCLUSION: There are many aspects to evaluating the changes in a symptom. Some symptoms occur with other simultaneous symptoms. The alleviation or aggravation of simultaneous symptoms could reflect the corresponding changes in a symptom. The changes of inducing factors are important to judging changes in symptoms.