Abstract: Speech has been a natural and effective way of communication, widely used in the field of information-communication and human–machine interaction. In recent years, various algorithms have been used for achieving efficient communication. The main purpose of automatic speech recognition (ASR), one of the key technologies in this field, is to convert the analog signals of input speech into corresponding text digital signals. Further, ASR can be divided into two categories: one based on hidden Markov model (HMM) and the other based on end to end (E2E) models. Compared with the former, E2E models have a simple modeling process and an easy training model and thus, research is carried out in the direction of developing E2E models for effectively using in ASR. However, HMM-based speech recognition technologies have some disadvantages in terms of prediction error rate, generalization ability, and convergence speed. Therefore, recurrent neural network–transducer (RNN–T), a typical E2E acoustic model that can model the dependencies between the outputs and can be optimized jointly with a Language Model (LM), was proposed in this study. Further, a new acoustic model of DL–T based on DenseNet (dense convolutional network)–LSTM (long short-term memory)–Transducer, was proposed to solve the problems of a high prediction error rate and slow convergence speed in a RNN–T. First, a RNN–T was briefly introduced. Then, combining the merits of both DenseNet and LSTM, a novel acoustic model of DL–T, was proposed in this study. A DL–T can extract high-dimensional speech features and alleviate gradient problems and it has the advantages of low character error rate (CER) and fast convergence speed. Apart from that, a transfer learning method suitable for a DL–T was also proposed. Finally, a DL–T was researched in speech recognition based on the Aishell–1 dataset for validating the abovementioned methods. The experimental results show that the relative CER of DL–T is reduced by 12.52% compared with RNN–T, and the final CER is 10.34%, which also demonstrates a low CER and better convergence speed of the DL–T.
Abstract: Bearing steel is a significant material for producing basic components in many industrial sectors, such as automotive, high-speed trains, and aerospace. In most cases, the bearings belong to the safety-relevant parts of these structures, so that extensive quality control measures are applied to ensure the entire assembly’s reliability and safety. In the last century, the precise instruments’ bearings were almost dependent on imports, which cost a large fortune. In recent years, the production technique and the production quality of domestic bearing steels keep improving, and the cleanliness keeps increasing. The qualities of some superior domestic bearing steels have become close to foreign bearing steels with high quality. However, the stability still needs to be improved, especially in the aspects of calcium aluminate inclusions and the titanium content in steels. To understand the gaps between domestic and foreign bearing steels, the differences in metallurgical properties of high-fatigue-life bearing steels, such as the main impurity elements and the characteristics of main inclusions, were compared in this paper. Fatigue properties of bearing steels and factors that cause fatigue fracture under various metallurgical properties were also compared. The cleanliness status of domestic bearing steels and the gap with foreign high-quality bearing steels were summarized. There are two types of controlling strategies of the cleanliness for bearing steels: 1) controlling the total oxygen content strictly to get an extremely low total oxygen content; 2) controlling the size and type of oxide inclusions with a relatively low total oxygen content. On this basis, in order to further improve the efficiency of domestic steel bearings, the development of the smelting technology and the integration control system for domestic steel bearings were analyzed and sorted out. Besides, the development direction of further improving the quality and fatigue life of domestic bearing steel was discussed.
Abstract: Amorphous alloys due to their unique microstructures exhibit high hardness, high strength, high wear resistance, high corrosion resistance, and a series of excellent properties, such as magnetic properties, hydrogen storage properties, and superconductivity. They have found application as a new generation of thermal spray materials, which are of interest in the engineering field. Since the 1980s, the preparation and application of bulk amorphous alloys have gradually become a research hotspot. However, preparing bulk amorphous alloys is seriously difficult and they have limited applications, hindering the replacement of conventional alloys and their wide use in various industries. As alternatives, amorphous alloy coatings have recently garnered research interest because of their similar properties to the bulk, lower cost, and wider applications. They are usually prepared by thermal spraying, which has great industrial applications. This article first introduced the theoretical framework of amorphous alloys and then the two aspects of wear resistance and corrosion resistance, expounded the research progress on the properties of thermally sprayed amorphous alloy coatings in detail, and systematically summarized the essential connection and fundamental contradiction of the wear resistance and corrosion resistance of amorphous alloy coatings. Finally, the limitations of thermal spraying for preparing amorphous alloy coatings were pointed out. Three problems are raised: (1) The basic theory of amorphous alloys is still in its infancy; (2) There are few types of alloy systems for preparing thermally sprayed amorphous alloy coatings; (3) The thermal spraying technology for preparing amorphous alloy coatings needs to be developed. Aiming at the above three problems, future research directions on the properties of thermally sprayed amorphous alloy coatings were proposed.
Abstract: Compared with the widely used plain carbon steels, high-strength low-alloy steels exhibit high tensile strength, excellent fatigue performance, good plasticity, and toughness, and have attracted considerable attention in recent years. In the strengthening and toughening of high-strength low-alloy steels, the addition of carbide-forming and nitride-forming elements (i.e., Nb, V, and Ti) promotes the formation of nanosized precipitates. Nanosized precipitate in high-strength low-alloy steels plays a significant role in the microstructure optimization, which could maintain the high mechanical properties and excellent corrosion resistance of the steel matrix. With the advancement of characterization techniques and simulation methods in the atomic scale over the past few decades, the effect of nanosized precipitate on the corrosion behavior of high-strength low-alloy steels has become increasingly clear. Based on the obtained achievements in China and abroad, the existing morphology of nanosized precipitate and its influence on hydrogen diffusion, uniform corrosion, stress corrosion cracking, and hydrogen-induced damage were reviewed systematically in this study. Results show that the influence of nanosized precipitates on the corrosion behavior of high-strength low-alloy steels depends on its size, quantity, and status of crystal deposition. The fine and (semi-)coherent precipitate in the steel matrix can significantly improve not only the corrosion resistance by refining the microstructure (including the substructure) but also the resistance to hydrogen-induced damage by acting as an irreversible hydrogen-trapping site and strongly restraining hydrogen diffusion. However, incoherent precipitates with a large size would deteriorate the corrosion resistance because of the loss of microstructure optimization. Finally, this study forecasts the influence of nanosized precipitate on fatigue corrosion of high-strength low-alloy steels, which has not been investigated in previous studies. The optimization of the corrosion resistance of high-strength low-alloy steels can be achieved by controlling the nanosized precipitates. Clarifying the influence of nanosized precipitate on corrosion behavior would contribute significantly to the development of high-quality high-strength low-alloy steels.
Abstract: Superhydrophobicity in the surface is a phenomenon in which the contact angle between the water and the corresponding surface is greater than 150° and the rolling angle is less than 10°. A superhydrophobic surface exhibits unique properties and has a wide range of application prospects in the field of self-cleaning, anti-corrosion, anti-icing, oil-water separation, and antibacterial agents. In addition to its unique self-cleaning properties, it can play a distinctive role in the fields of building maintenance, anti-biological corrosion in ship bodies, medical antibacterial agents, etc. At present, low-surface-energy materials commonly used to construct superhydrophobic materials mainly include alkane compounds, organosilicon compounds, and fluorine-containing compounds. However, these materials generally have problems of high production costs, large environmental pollution, and complex preparation processes, which severely restrict the industrial production and application of superhydrophobic coatings. Graphene is a two-dimensional honeycomb-structured material formed by the covalent bonding of carbon atoms through sp2 hybrid orbitals. It is the basic unit of graphite, and it is the thinnest two-dimensional material found so far. As a class of materials with outstanding physical and chemical properties, graphene materials have always received extensive attention because of its high electrical conductivity, high thermal conductivity, high specific surface area, high light transmittance, and excellent mechanical properties. Therefore, graphene has been considered a promising material in aerospace, petrochemical, marine ships, and other fields. The construction of superhydrophobic surfaces based on graphene is a relatively new direction in the research of superhydrophobic surfaces at present. Although graphene-based superhydrophobic materials have shown excellent performance in the laboratory, they have not been used on a large scale in industrial production. In this paper, the principles of superhydrophobic surfaces were summarized, focusing on the research status of graphene-based super-hydrophobic materials preparation technology, including surface modification, deposition modification, laser induction, dip-coating method, and layer-by-layer self-assembly. The applications of graphene-based super-hydrophobic materials in the fields of self-cleaning, oil-water separation, anti-icing, corrosion resistance, and anti- bacterial agents were also introduced. Finally, this paper presents the prospective future research directions of graphene-based super-hydrophobic materials.
Abstract: As a metal-free photocatalyst with high catalytic performance, carbon nitride is non-toxic, harmless, and stable in the natural environment. Owing to its facile synthesis, stable physical and chemical properties, tunable structure, and suitable band gap, graphite-like carbon nitride (g-C3N4) plays an increasing role in the field of photocatalysis. It has attracted extensive attention in the fields of evolution of hydrogen and oxygen via water-splitting hydrolysis and in the degradation of organic pollutants. In particular, g-C3N4 is identified to have a high specific surface area (SSA) because of its special lamellar structure. Meanwhile, the abundant pores intrinsic in it are able to provide both transporting channels for photogenic carriers or reactive species and a large number of active sites for redox reactions. These merits endow it with high photoelectrical properties. The preparation methods of the pore structures of such catalyst include hard templates, soft templates, and non-template ones. The hard template method enables the preparation of regular pore structures but requires additional removal treatment. However, the soft templates can be decomposed during the high-temperature preparation of g-C3N4, which avoids the use of toxic reagents and consequently is harmless to the environment, and the template-free method does not involve any templates, which will simplify the experimental process from the aspect of sample preparation with reduced cost. In this paper, the advantages and disadvantages of various preparation methods were elaborated and compared based on the literature review in recent years. The developments and applications in the environmental and energy aspects were summarized by combining the commonly used modification methods, which provided the perceptions with respect to the development of metal-free g-C3N4-based photocatalysts in the future. Further, the photocatalytic mechanism was explained, and the four different precursors of g-C3N4 were compared. Finally, the ongoing outlook and perspectives will be covered in this review.
Abstract: As the final stage of intelligent vehicle, traffic accidents can be effectively reduced by automatic driving. However, neither the technology nor the regulations are mature for autonomous driving. The lane-keeping assist system is one of the important components of the advanced driver-assistance system. When driver fatigue or inattention is detected, the system can effectively prevent the vehicle departure from the lane. Information such as vehicle status, driver status, and external environment can be used by the lane-keeping assist system based on human–machine dynamic cooperative control, thereby smoothly changing the driving rights between the driver and the automatic controller. The system can keep the vehicle in the lane while complying with the driver's intention, thereby ensuring vehicle safety and driver comfort. The research status and future development suggestions on lane-departure decision models, dynamic allocation of driving rights, and performance evaluation were analyzed in this paper. Regarding lane-departure decision models, different decision models considering the driver's state should be developed. The decision model can be established as an adaptive adjustment model and also should allow the manual adjustment of the preset parameters according to the driver’s preferences and the external driving environment. Concerning the allocation of driving rights, a more reasonable dynamic allocation of driving rights should be explored, and intelligent optimization algorithms or control models should be designed. Regarding performance evaluation indicators, evaluation indicators related to the reduction of human–machine conflict and the amount of control effort should be added. A scientific and complete subjective evaluation system should be developed. Future studies on lane-keeping assist system based on human–machine cooperative control should deeply integrate driver factors, issue real-time warnings and active intervention, and perform complete testing and evaluation of the system.
Abstract: Under heavy rainfall, the pore air pressure in the unsaturated zone of a dump hinders rainwater infiltration in loose soil, which further affects the safety and stability of the dump. However, traditional analysis methods often regard pore air pressure as atmospheric pressure and ignore its impact on dump safety. Relying on the high bench dump project of a copper mine in Jiangxi, basing on the field test and survey results and combing with the horizontal slice of a typical dump profile, the seepage law and safety stability of a high bench dump with traditional methods while considering the pore air pressure were analyzed. Moreover, the influence of pore air pressure on a wet front, pore water pressure, and slope safety factors of high bench dump under heavy rainfall conditions were discussed. The research results show that pore air pressure at the initial stage of rainfall infiltration is not significant, and pore air pressure does not have a direct impact on the stability of the high bench dump. However, as the rainfall continues, the effect of the pore air pressure begins to appear, reducing the infiltration rate of the high bench dump. Further, the downward movement speed of the wetting front becomes slower, the pore water pressure rises slowly, and the influence of the heavy rainfall delays the stability of the high bench dump. In the middle of rainfall infiltration, the pore air pressure remains constant, the delay effect varies, and the penetration depth increases. In the late stage of rainfall infiltration, when the wetting front moves down to the critical plane of the layering, the pore air pressure balance is destroyed, continuing to increase to a new constant value, which increases the impact on the high bench dump. When the traditional method of wetting front and considering the pore air pressure of wetting front move down to the same depth, the safety factor of the high bench dump under the action of pore air pressure is obviously reduced. The research results provide a theoretical basis for long-term safe operation and disaster monitoring and early warning of high bench dump under heavy rainfall conditions.
Abstract: Iron ore sintering is a process in which iron ore powder, flux, iron-bearing dust, solid fuel (such as coke powder), and return fines are mixed in a certain proportion, granulated, and then processed into agglomerates by high-temperature generated by solid-fuel combustion, which is an important process prior to blast furnace ironmaking. The iron ore sintering process is an important emitter of atmospheric particles in which alkali metal elements in a sinter bed contribute to the formation of fine particles during combustion, aggravating particulate emissions. Using biomass materials such as charcoal to replace coke in the sintering process can significantly alleviate the emission of both greenhouse gases and pollutants. However, owing to the high content of alkali metals in biomass and their poor combustion characteristics, alkali-metal-related problems inevitably arise. In this study, a small sintering experiment was conducted in a volatilization condensation test facility and analyses were performed based on data obtained by X-ray fluorescence spectroscopy, scanning electron microscopy energy dispersive spectrometer, and inductively coupled plasma-atomic emission spectrometry followed by thermodynamic simulation. The purpose of these analyses was to investigate the laws associated with alkali metal migration and enrichment, removal rate of alkali metal elements, and influence of technological measures on removal process in iron ore sintering using charcoal and coke as fuel with iron-bearing dust added. The results show that K is easier to remove than Na, and the alkali compounds volatilized into a flue gas mainly contain KCl with small amount of NaCl. With the same fuel mass fraction the removal rate of alkali metal in the sintering process using charcoal as fuel is less than that using coke. As the alkali metal compounds in the downstream flue gas migrate, they collide with the raw material particles because of the inertial effect. In addition, owing to the low temperature of the raw materials in the low bed, alkali metal compounds tend to condense and deposit on the particles’ surface. During the sintering process, a large number of alkali metal compounds discharged into the waste gas are trapped and absorbed by the low bed, and the alkali metal chloride accumulated in the low bed promotes the removal of chloride from the alkali metal. With the addition of CaCl2, the removal rate of K and Na when using charcoal as fuel is higher than that using coke. Accordingly, the content of K and Na in sintering products with charcoal as fuel is lower than that using coke. The use of biomass as fuel in iron ore sintering in combination with chlorine removal process is feasible and has good prospects.
Abstract: Diluted magnetic semiconductors (DMSs) have attracted much attention in recent years due to their dual control of charge and spin degrees of freedom in carriers. Potential applications of DMSs include spin light-emitting diodes, spin field-effect transistors, magnetoresistance random access memory, and ultrafast optical switches. However, the Curie temperature (Tc) of most DMSs below ambient temperature limits the efficiency of these devices. Thus, the biggest challenge for developing DMS materials has been producing host materials that exhibit ferromagnetic behavior above ambient temperature. A series of theoretical simulations and experiments show that the Tc value of ZnO-based DMSs could satisfy this requirement. Incorporation of selective transition metal elements (e.g., Fe2+, Co2+, Ni2+, and Mn2+) has been confirmed as an effective way to enhance the magnetic properties of ZnO. In the present research, (In, Co) co-doped ZnO (ICZO) films were deposited by radio frequency sputtering at 100 ℃ on a glass substrate. The sputtering process was performed through In, Co, and ZnO co-sputtering. The presence of ICZO films has been adjusted by changing the target sputtering power. The variation of electric and magnetic properties of the film was studied with different In content. The composition, morphology, structure, electric and magnetic properties of films were characterized by field emission scanning electron microscopy, high-resolution transmission electron microscopy, atomic force microscopy, electron probe microanalyzer, X-ray diffractometer, Hall effect analysis, and vibrating sample magnetometer. The effect of carrier concentration on the magnetic properties of the film was analyzed extensively. These results show that, in the presence of In, the carrier concentration increases, thereby optimizing films’ conductivity. All the films present ferromagnetic behavior at room temperature. Besides, with an influence of bound magnetic polaron model and carrier-mediated exchange mechanisms on the film’s saturation magnetization, carrier-concentration dependent behavior can be expressed in three different regions.
Abstract: In this study, ultra-high-strength DH steels with different phase compositions were designed, their tensile strengths were greater than 1300 MPa, and the multiphase microstructures contained ferrite, martensite, retained austenite, and small amounts of carbides. The effects of different phase compositions on the mechanical properties and strain hardening behaviors of the ultra-high-strength DH steels were compared, and the mechanism of the retained austenite in the ultra-high-strength DH steels was comprehensively studied. The results show that with the increase in the volume fraction of martensite and retained austenite and decrease in the ferrite volume fraction, the yield strength and tensile strength increase, whereas, the elongation rate first increase and then decrease. The decrease in the soft-phase ferrite volume fraction and increase in the volume fraction of the hard martensite phase led to an increase in yield strength and tensile strength. Compared with tempered martensite, quenched martensite could improve the strength more significantly. The retained austenite transformed in the tensile process was the main cause of the change in elongation. The remarkable banded structure in the microstructure will cause a significant decrease in elongation after necking. The analysis of the strain hardening behavior show that the strain hardening rate decrease with the increase in the true strain. When the true strain was greater than 2%, the strain hardening rate of the steels followed the order: DH1 > DH2 > DH3; this trend was mainly influenced by the ferrite volume fraction. The strain hardening rate of DH2 was higher than those of DH1 and DH3 when the true strain was greater than 5.73%, which was mainly related to the more significant transformation-induced plasticity (TRIP) effect in the DH2. In addition to the retained austenite volume fraction, the carbon content in the retained austenite also had a significant effect on the TRIP effect. The high proportion of the hard-phase martensite, appropriate proportion of the soft-ductile-phase ferrite, and retained austenite contributed to the DH2 steel having the greatest tensile strength and elongation (13.17 GPa·%); moreover, the yield strength was 880 MPa, tensile strength was 1497 MPa, uniform elongation was 6.71%, total elongation was 8.8%, elongation after necking was 2.09%, and yield ratio was 0.59.
Abstract: PH13-8Mo is a precipitation-strengthened, martensitic stainless steel with ultra-high strength, and satisfactory toughness and plasticity. It is generally utilized in the fields of aviation and traditional energy because of its remarkable mechanical properties and corrosion resistance, as well as its stable performance in harsh service environments. Because of the wide applications of PH13-8Mo stainless steel and the complex corrosive environments it faces, its corrosion resistance is of great significance for deciding the lifetime and safety of aircrafts and ships. However, limited by factors, including a long outdoor exposure test cycle and a large professional experimental site required, only a few reports exist on the atmospheric corrosion behavior and mechanism of PH13-8Mo stainless steel, especially the influence of chemical pre-passivation on the steel still remains relatively uninvestigated. Therefore, the outdoor exposure tests of two samples of PH13-8Mo stainless steel, with and without nitric-acid-passivated film, respectively, were performed in a semi-rural atmospheric environment in Beijing for five years. The effect of the pre-passivation treatment on the corrosion behavior and mechanism of PH13-8Mo stainless steel was investigated by observing the surface morphology, using the mass loss method, analyzing the passivated film and corrosion products, testing the mechanical properties, and conducting fracture analyses. The results show that the pre-passivation treatment with nitric acid reduces the pitting corrosion and decreases the corrosion rate. The pre-passivation treatment with nitric acid delays the destruction of Cl? on the passivated film and also delays the nucleation of the pitting by increasing the hydroxide content and the atomic ratio of Cr/Fe of the passivated film, and it increases the surface Kelvin potential as well, further enhancing the protectiveness of the surface film. Additionally, the pre-passivation treatment with nitric acid reduces the loss in the mechanical properties after long-term exposure to the semi-rural atmospheric environment, although it has little effect on the fracture mode, and both the steel samples exhibit the typical morphologies of a ductile fracture.
Abstract: The layered characteristics of the material in the thickness direction of the metal laminate make it more prone to uneven plastic extension during the thinning, rolling, flattening, and straightening process, resulting in plate-shaped warpage defects and cause the plate-shaped warpage of the metal laminate. The behavior is significantly different from that of a homogeneous metal plate. In this paper, the classical elastic mechanics method was used to establish an analytical computational mechanical model for the warpage of the metal laminate, and the quantitative relationship between the uneven extension in the thickness direction and the warpage of the plate shape was obtained; the online and offline states of the metal laminate were established, respectively. The finite element numerical simulation model of warpage deformation validated the analytical computational mechanics model; based on this, it revealed the mechanical roots of the shape warping defects of metal laminates and the effect of various factors on the shape warpage defects of metal laminates. The influence law of evolution and the difference in warpage deformation between double-layer and three-layer structure laminates and homogeneous plates, as well as the difference in warpage deformation between copper/carbon steel laminates and stainless steel/carbon steel laminates, were compared. Studies have shown that the warpage height of the metal laminate is proportional to the elongation difference and thickness ratio, and it is inversely proportional to the thickness. The greater the difference between the shear modulus of the base layer and the cladding layer is, the larger the effect of the thickness ratio on the warpage deformation of the metal laminate will be. Based on the numerical model, simulation studies were conducted on the deformation behavior and regularity of the plate shape warping of the laminated plate under the ideal uniform distribution of the initial temperature and the stress relief annealing process, and it was compared with that of the homogeneous plate. Finally, a sample of the warped laminate was taken at an industrial production site, and the initial extension difference was reversed by measuring its bending deformation. The result verifies the accuracy of the analytical computational mechanical model.
Abstract: The reheat furnace, located between the continuous caster and the hot rolling mill, plays the role of buffer coordination zone, and is one of the most important production equipment in the hot rolling process. As reheat furnaces were the largest energy-consumer group in the hot rolling process, their schedule optimization was of great importance to achieve high production efficiency and reduce energy consumption. In this paper, a new reheat furnace production scheduling method with the target of minimum fuel consumption was proposed. First, the energy inputs and outputs from the reheat furnace were analyzed based on the first law of thermodynamics, then the equation for calculating of the fuel consumption was derived. Second, various production constraints were summarized to consider the actual characteristics of the dispatching plan in reheat furnaces, and the mathematical model of scheduling optimization was constructed with the minimum fuel consumption set as the optimization objective. The adaptive differential evolution algorithm and the tabu search algorithm were applied to obtain the optimal solution. The differential evolution algorithm could dynamically adjust the scaling factor and the crossover rate according to the change of the fitness function value of each generation of individuals, and this adaptive strategy could balance the ability of development and exploration of the algorithm. After the model was validated with actual production data, the feasibility and effectiveness of the algorithm were verified by nine groups of actual billet production cases. Furthermore, to explore the influencing factors of energy consumption of reheat furnace, two evaluation parameters, μ1 and μ2, were defined to quantify the matching degree of time series of the buffer waits and the heating processes to ideal production in reheat furnaces. According to the sensitivity analysis of the relationship between the fuel consumption and the two evaluation parameters, it was found that their sensitivity gradually decreased when the ratio of continuous casting billet arriving at the reheat furnace to hot rolling increased from 0.5 to 2.
Abstract: On analyzing the details of kinetic links of parts and structures of aircrafts, one can find few bad links. But fastener hole is the weakest link where abnormal stress is produced and initiation of crack occurs. The initial fatigue quality of aircraft wing flange fastener is the key parameter, which affects the durability of aircraft structure. The initial fatigue quality of structural details is usually characterized by the equivalent initial defect size (EIFS) and the time to crack initiation (TTCI). To evaluate the initial fatigue quality of aircraft wing flange fastener hole details, this paper first carried out fatigue tests at high-, medium- and low-stress levels on the BXXX aluminum alloy fastener hole specimens generally used in aircraft wing flange structures, and obtained three groups of (a?t) datasets about crack length a and fatigue life t through fracture interpretation and back stepping. On this basis, the EIFS governing equation was used to evaluate the EIFS value of each specimen, and it is found out that there is no significant difference in equivalent initial flaw size under different stress levels; TTCI distribution of structural details is obtained, and the economic life of specified stress level under 95% confidence level of fastener hole structural details was predicted, and compared with the design life; a structural detail equivalent to initial flaw size model under different exceedance probability P was proposed. Based on the given 5% crack exceedance probability, the general EIFS distribution of structural details was evaluated. The comprehensive evaluation results were obtained through the above triple evaluation of the initial fatigue quality of the fastener hole details: the general EIFS distribution and the EIFS value of each test piece are less than the allowable value, and the economic life is greater than the allowable value, so the original fatigue quality of the details of the fastening holes of the aircraft flange meets the stringent requirements.
Monthly, started in 1955 Supervising institution：Ministry of Education Sponsoring Institution：University of Science and Technology Beijing Editorial office：Editorial Department of Chinese Journal of Engineering Publisher：Science Press Chairperson：Ren-shu Yang Editor-in-Chief：Ai-xiang Wu ISSN 2095-9389CN 2095-9389
