Search

Ancient glass is extremely susceptible to weathering by the influence of the buried environment, resulting in a change in the proportion of glass components. In order to classify different kinds of glass, this paper uses k-means++ clustering method to analyze the classification law, and summarizes the major and minor chemical composition data of the cluster center, so as to establish a glass classification model. In order to identify unknown types of glass, this paper mixes the data of eight groups of unknown types of glass into the known data, outputs the types of eight groups of glass through cluster analysis, calculates the center distance of the lead barium glass group to the subclass of the type in these eight groups, and then divides the subclass, and at the same time divides the subclass of the high potassium glass in the eight groups.

To enhance the level of refined load decomposition of the power system and make full use of seasonal change information to improve the prediction performance further, this paper proposes a seasonal short-term load combination prediction model of the power system based on modal decomposition and feature fusion multi-algorithm hybrid neural network model, i.e., the characteristics of load components are analysed for different seasons, and the corresponding models are established respectively. Firstly, The ICEEMDAN (Improved complete ensemble EMD) method decomposes the four-season load, and a new sequence is obtained based on the RCMFE (refined composite multiscale fuzzy entropy) reconstruction of each decomposition component. Secondly, the correlation between different decomposition components and different features is measured using the mRMR (Max-Relevance and Min-Redundancy) method to filter out the subset of features with high correlation and low redundancy. Finally, the BiLSTM (Bi-directional Long Short-Term Memory) model based on the Bayesian optimisation algorithm is used to predict different components of different seasonal loads separately, and the predicted values are accumulated to obtain the final results. According to the experimental findings, the proposed method can successfully balance the issues of prediction accuracy and prediction time while having a higher level of prediction accuracy than the current prediction methods. It is confirmed that the proposed method can effectively address the load power variation brought on by seasonal differences in different regions.

In order to explore the influence of textured sawteeth on saw blades cutting and wear performance, linear micro textures perpendicular to the chip flow direction were fabricated on the rake face, main flank face and secondary flank face by laser machining, respectively. The cutting tests were carried out on sawing platform by different cutting speed, and the cutting forces, noise, temperatures, machined surface quality and sawteeth wear were studied. The results indicated that textures fabricated on the secondary flank face can effectively reduce friction with the machined surface and improve the surface quality, and the roughness Ra was decreased about 2.5% ~ 12.5% compared with traditional saw blade. The improvement of saw blades cutting performance by preparing micro textures on the main flank face was greater than the textures fabricated on the rake face. Due to the synergistic action of textures at different cutting faces, the cutting force, noise and temperature of saw blades with textures prepared on all cutting surfaces was the lowest. The main wear forms of sawteeth were tip wear, surface adhesion wear and oxidation wear. Although the derivative cutting phenomenon was occurred, the micro textures were not filled completely, it signified that the micro textures still played the role of stored cutting fluids, reduced contact area and formed lubrication film.

Introduction: Long-distance running is a typical physical endurance sport. The athletes’ fitness level plays a dominant and central role in the components of their competitive ability. Whether long-distance runners can win in fierce competition depends mainly on the endurance of their physical fitness. Objective: To analyze the physical training methods of long-distance runners and discuss the improvement of speed and strength of long-distance runners through physical training. Methods: This paper uses literature materials, expert interviews, and experimental methods to research the training practice of middle and long-distance runners in colleges and universities. The data collected comprised an experimental protocol performed on volunteer long-distance runners. The above research determined the effect of physical training on speed and strength in long-distance runners. Results: After the 12-week experimental intervention, the overall strength, flexibility, and flexibility of the long-distance runners were improved, and the data were statistically significant (P

Lubricant grease is a special material commonly used in the field of nuclear power plant. It is widely used in the sliding fit and press fit parts of bolts, studs and valves to prevent thread wear, seizing as well as stress corrosion cracking of fasteners during assembly, service and disassembly. In this paper, the performance of lubricant materials such as wear resistance and high temperature oxidation resistance under irradiation environment were studied. The results show that the lubricant grease does not change significantly and there is no grease stratification after irradiation with 0.1MGy integrated irradiation dose. However, after irradiation with 10MGy integrated irradiation dose, the irradiation has an obvious destructive effect on the oxidation resistance performance of the grease, and the grease appears obvious stratification. With the increase of irradiation dose, the thermal decomposition temperature first decreases and then increases. Under 0.1MGy irradiation dose, the thermal decomposition loss of the sample changes little, but at 10MGy irradiation dose, a large amount of mass loss occurred, up to more than 80%. The four-ball friction experiment shows that its extreme pressure resistance improves with the increase of irradiation dose, and the sintering load increases. These data provide technical guidance for the long-term reliability of nuclear power fastener materials in service.

Background The aim of our study was to investigate the clinical characteristics and pathogenesis of tumor-induced acute pancreatitis (AP), and to develop a reliable prediction model of the clinical features to guide the diagnosis and treatment. Methods Patients with AP between January 2013 and December 2021 were enrolled in the study and were subdivided into the tumor group and the non-tumor group. The tumor group was subdivided into three groups based on the primary sites. Characteristic parameters, laboratory and imaging results were compared between groups. Least absolute shrinkage and selection operator regression model, XGBoost and random forest model were used to select the predictors associated with tumor-induced AP. Logistic regression analysis was used to validate the performance of the selected predictors and a nomogram was established to provide individualized probability of a tumor origin for AP. Results A total amount of 8970 patients were admitted for AP during the study period, and 8637 AP patients were enrolled in the study. Of these, 100 cases (1.16%) were tumor-induced AP. The tumor group was significantly older than the non-tumor group (t = 6.050, p = 0.000). Mild AP was observed in 90 cases, moderate AP in 9 cases and severe AP in one case. Tumors respectively originated from distal bile duct (14 cases), ampulla (13 cases) and pancreas (73 cases). The median time from initial AP to tumor diagnosis was 8.57 weeks and the median number of episode was 2 in the tumor group, which significantly surpassed the non-tumor group (p = 0.000). Age, white blood cell count, percentage of neutrophils, pancreatic or bile duct dilation and recurrent attacks were selected independent predictors for tumor origin. A nomogram model based on these factors was established. Conclusion For patients with agnogenic AP, elderly man, recurrent attacks, pancreatic or bile duct dilatation and continuous no significant increase of inflammatory markers prompt to further screening of pancreatic biliary and ampulla.

Multi-view information fusion can provide more accurate, complete and reliable data descriptions for monitoring objects, effectively improve the limitations and unreliability of single-view data. Existing multi-view information fusion based on deep learning mostly focuses on the feature level and decision level, with large information loss, and does not distinguish the view weight in the fusion process. To this end, a multi-view data level information fusion model CAM_MCFCNN with view weight was proposed based on a channel attention mechanism and convolutional neural network. The model used the channel characteristics to implement multi-view information fusion at the data level stage, which made the fusion position and mode more natural and reduced the loss of information. A multi-channel fusion convolutional neural network was used for feature learning. In addition, the channel attention mechanism was used to learn the view weight, so that the algorithm could pay more attention to the views that contribute more to the fault identification task during the training process, and more reasonably integrate the information of different views. The proposed method was verified by the data of the planetary gearbox experimental platform. The multi-view data and single-view data were used as the input of the CAM_MCFCNN model and single-channel CNN model respectively for comparison. The average accuracy of CAM_MCFCNN on three constant-speed datasets reached 99.95%, 99.87% and 99.92%, which was an improvement of 0.95%, 2.25%, and 0.04%, compared with the single view with the highest diagnostic accuracy, respectively. When facing limited samples, CAM_MCFCNN had similar performance. Finally, compared with different multi-view information fusion algorithms, CAM_MCFCNN showed better stability and higher accuracy. The experimental results showed that the proposed method had better performance, higher diagnostic accuracy and was more reliable, compared with other methods.

Pickering emulsion is a new type of stable emulsion made by ultrafine solid particles instead of traditional surfactants as stabilizers, which has received widespread attention in recent years. The preparation methods of stator-rotor homogenization, high-pressure homogenization, and ultrasonic emulsification were compared with others in this work. The main factors affecting the stability of Pickering emulsion are the surface humidity of the solid particles, the polarity of the oil phase, and the oil–water ratio. These factors could affect the nature of the solid particles, the preparation process of Pickering emulsion, and the external environment. Consequently, the long-term stability of Pickering emulsion is still a challenge. The tribological investigations of Pickering emulsion were summarized, and the multifunctional Pickering emulsion shows superior prospects for tribological applications. Moreover, the latest development of Pickering emulsion offers a new strategy for smart lubrication in the near future.

Introduction: The formation and propagation of pulse waves are mainly accomplished by coordinating the heart and the vascular system. The contraction and relaxation of the heart are the sources of pulse waves. The aorta vibrates regularly as the heart contracts. This vibration propagates forward along the elastic blood vessel to form a pulse wave. The pulse wave contains very rich physiological and pathological information about the cardiovascular system. If there is a problem with the heart's structure, it can cause abnormal pulse waveforms. Objective: This article analyzes pulse waveform changes and blood flow during high-intensity interval training. It combines the test results to guide the exercise rehabilitation treatment of patients with chronic diseases. Methods: Pulse waves were collected from subjects under different exercise loads and the characteristics of pulse wave parameters under intermittent exercise were studied. Results: An athlete's pulse wave response is different in the case of high-intensity intermittent exercise. There are differences in the cardiovascular response of patients with different body weights. Conclusion: High-intensity interval training can improve the cardiovascular function of patients with chronic diseases and affect their pulse waveform. Level of evidence II; Therapeutic studies - investigation of treatment results. RESUMO Introdução: A formação e propagação de ondas dos batimentos cardíacos resultam principalmente da coordenação entre o coração e o sistema vascular. A contração e o relaxamento do coração produzem ondas de batimento cardíaco. A aorta vibra regularmente a medida em que o coração se contrai. A vibração se propaga no vaso sanguíneo elástico para formar uma onda de batimento cardíaco. Esta onda contém informações fisiológicas e patológicas muito ricas sobre o sistema cardiovascular. Se há algum problema com a estrutura cardíaca, ondas anormais podem resultar. Objetivo: Este estudo analisa as alterações em ondas de batimentos cardíacos e o fluxo sanguíneo durante treinos de intervalos de alta intensidade. Combina os resultados dos testes para orientar o tratamento de exercícios de reabilitação em pacientes com doenças crônicas. Métodos: Ondas de batimentos cardíacos foram coletadas de indivíduos praticando exercícios com cargas diferentes. As características dos parâmetros das ondas de batimento cardíaco relacionadas a exercícios intermitentes foram estudadas. Resultados: A resposta das ondas de batimentos de atletas é diferente em exercícios intermitentes de alta intensidade. Existem diferenças na resposta cardiovascular de pacientes com diferentes pesos corporais. Conclusão: O exercício de intervalos de alta intensidade pode melhorar a função cardiovascular de pacientes com doenças crônicas e afetar as ondas de batimentos cardíacos. Nível de evidência II; Estudos terapêuticos – investigação de resultados de tratamento. RESUMEN Introducción: La formación y propagación de ondas de los latidos cardíacos resultan principalmente de la coordinación entre el corazón y el sistema vascular. La contracción y el relajamiento del corazón producen ondas de latido cardíaco. La aorta vibra regularmente a la medida que el corazón se contrae. La vibración se propaga en el vaso sanguíneo elástico para formar una onda de latido cardíaco. Esta onda contiene informaciones fisiológicas y patológicas muy ricas sobre el sistema cardiovascular. Si hay algún problema con la estructura cardíaca, puede causar ondas anormales. Objetivo: Este estudio analiza las alteraciones en ondas de latidos cardíacos y el flujo sanguíneo durante entrenamientos de intervalos de alta intensidad. Combina los resultados de las pruebas para orientar el tratamiento de ejercicios de rehabilitación en pacientes con enfermedades crónicas. Métodos: Ondas de latidos cardíacos se recogieron de individuos practicando ejercicios con carga diferentes. Las características de los parámetros de las ondas de latido cardíaco relacionadas a ejercicios intermitentes se estudiaron. Resultados: La respuesta de las ondas de latidos de atletas es diferente en ejercicios intermitentes de alta intensidad. Existen diferencias en la respuesta cardiovascular de pacientes con diferentes pesos corporales. Conclusión: El ejercicio de intervalos de alta intensidad puede mejorar la función cardiovascular de pacientes con enfermedades crónicas y afectar las ondas de latidos cardíacos. Nivel de evidencia II; Estudios terapéuticos – investigación de resultados de tratamiento.

The Early Ordovician stromatolites in the study area are mainly exposed at the bottom and middle and lower parts of the Second Member of Nanjinguan Formation, the top of the Fourth Member of Nanjinguan Formation, the middle of the Second Member of Fenxiang Formation and the bottom of the First Member of Honghuayuan Formation. In order to find out the controlling factors of Lower Ordovician stromatolites development in the study area, the analysis data of carbon, oxygen isotope samples, macro element samples as well as their variation characteristics are studied and then combined them with previous research results, which is eventually beneficial for reaching the conclusion: sea level change is one of the main factors controlling the formation of stromatolites. There are five sea level change cycles in the Early Ordovician period. The analysis of sea level change and accommodation space variation characteristics show that when the growth rate of the accommodation space is approximately equal to that of carbonate, the circulation of seawater is well, and the amount of light and oxygen is sufficient, so that the cyanobacteria organism can be multiplied in large quantities. The growth and development provide favorable conditions, and favorable conditions are provided for the growth and development of stromatolites; The peak changes in CaO content and CaO/MgO ratio indicate that the formation period of stromatolites is arid climate environment with high water temperature and large evaporation. Prokaryote reproduction is suitable for the environments with high seawater cleanliness. When the amount of land-based debris injected into the sea increases, the turbidity of water will lead to a large number of deaths of algae microorganisms that form stromatolites, and the stromatolitic microbial mats cannot be preserved. In addition, the growth and predation of macro-organisms play a restrictive role in the development of stromatolite-forming micro-organisms blue-green algae. According to the actual situation of the development of the laminated rocks in the study area, what is the dominant function in the formation and decline of stromatolites between the evolution of metazoans and changing environments is discussed in the study.

In the pressent work, nanosized poly (N-isopropyl acrylamide) (PNIPAM) microgels were prepared and used as lubricant additives in bovine calf serum (BCS) for titanium alloy/ultra-high molecular weight polyethylene contact. The effects of sliding speed, load, and temperature on the lubrication behavior were studied on a pin-on-disc tribometer. The tribological results showed that the PNIPAM microgels can significantly improve the lubricity of BCS solution. The PNIPAM microgels exhibited notable temperature-sensitive lubrication characteristics. When the temperature was close to the low critical solution temperature of the PNIPAM microgels, the contact had the lowest friction coefficient due to the formation of a good lubricating layer with collapsed microgels and proteins. This discovery contributes to establishing a new strategy for friction-reduction and antiwear of titanium alloy artificial joint materials.