Search

Based on the assembly and inspection process of projectiles and rockets, this paper studies and analyzes the inspection link and content setting of welding and assembly on the projectile. Combined with the characteristics of the components, it proposes three aspects: inspection of the components, inspection before power-on screening, and pre-delivery inspection after final assembly. The research results of this paper can effectively verify the state of the projectiles and rockets after welding and assembly and improve the assembly quality of the productss.

Internet of Energy (IoE) is an advanced form of energy system development. From theoretical exploration to engineering practice, top-level design and scientific IoE system planning is critical for realizing IoE, and a crucial guarantee for the successful implementation of large-scale IoE projects. In this paper, we study the theoretical basis of IoE planning, analyze, and summarize the main planning methods of conventional energy systems and IoE development planning, and provide IoE planning approaches based on “grid-information-value.” Finally, we elaborate the planning direction, concepts, and key points at all levels of the energy grid, information support, and value creation.

Due to the limitation of volume and weight, the missile body parameters of the micro tailless air-to-ground missile have a large range during flight, and the characteristics of the rolling channel are greatly different from those of conventional missiles, the stability control of the roll channel is greatly affected by the error of the actuator. Under the classic PID control, the HWIL simulation results show that the jitter of roll angle is obvious, and the anti-disturbance ability of the system is poor. Based on the classic PID, fuzzy control is introduced to optimize the design of rolling channel by using fuzzy online self-correcting PID control. The results of the hardware-in-the-loop simulation show that the jitter of roll angle is suppressed, which improves the characteristics of the roll channel and the control efficiency.

This paper, A model reference adaptive control method based Lyapunov stability theory is proposed, because it is difficult for the control of inclined channel of missile, due to large disturbance and the dramatic change of missile parameter during the flight. The core strategy is that the real system can be adjusted automatically and in real time to be consistent with the reference model as far as possible, when the output of the real system is different from that of the reference model, so that the real system can run in the best state, this control method can well adapt to the changes of control parameters and external environment. The rationality and validity of the method has been verified by mathematical simulation.

A key component of the differential diagnosis of isolated hyperbilirubinemia (HB) is distinguishing between hemolytic and non-hemolytic types. Routine hemolysis screening markers have unsatisfactory sensitivity and specificity. Erythrocyte (RBC) lifespan shortening, the gold standard marker of hemolysis, is seldomly measured due to the cumbersome and protracted nature of standard methods. A new Levitt’s CO breath test method may enable simple, rapid RBC lifespan measurement. In this pilot prospective diagnostic study, Levitt’s CO breath test was evaluated to discriminate hemolytic from non-hemolytic HB in adults. One hundred and thirty eligible non-smoking adult patients who were aged 18 or older, referred for chronic (>6 months) isolated HB or had a known diagnosis of isolated HB of a rare cause, were recruited, including 77 with non-hemolytic HB and 53 with hemolytic HB. ROC curve analysis was applied to determine the optimal cutoff for discriminating between hemolytic and non-hemolytic HB, and the performance was calculated. Results showed that the mean RBC lifespan in non-hemolytic HB (93 ± 26 d) was reduced (p = 0.001 vs. normal reference value of 126 d), but longer than that in hemolytic HB (36 ± 17 d; p = 0.001). RBC lifespans did not differ significantly between 26 patients with simple hemolytic HB (32 ± 14 d) and 27 patients with a Gilbert syndrome comorbidity (40 ± 18 d). ROC curve analysis revealed an optimal lifespan cutoff for discriminating between hemolytic and non-hemolytic HB of 60 d (AUC = 0.982), with a diagnostic accuracy of 95.4%, 94.3% sensitivity and 96.1% specificity respectively. These results indicate that Levitt’s CO breath test seems to be very sensitive and specific for detecting hemolysis in adult patients with chronic isolated HB, and could enable simple, rapid, and reliable differential diagnosis of isolated HB. A large-scale validation study of the method is warranted.

Measuring quasar distance through joint analysis of spectroastrometry and reverberation mapping observations is a new method for driving the development of cosmology. In this paper, we carry out detailed simulation and analysis to study the effect of four basic observational parameters (baseline length, exposure time, equivalent diameter and spectral resolution) on the data quality of differential phase curves (DPCs), and furthermore on the accuracy of distance measurement. In our simulation, we adopt an axisymmetrical disk model of a broad line region (BLR) to generate differential phase signals. We find that the differential phases and their Poisson errors could be amplified by extending the baseline, while the influence of optical path difference errors can be reduced during fitting the BLR model. Longer exposure time or larger equivalent diameter helps reduce the absolute Poisson error. Therefore, the relative error of DPCs could be reduced by increasing any of the above three parameters, then the accuracy of distance measurement could be improved. In contrast, the uncertainty of absolute angular distances (D A) could be improved with higher spectral resolution, although the relative error of DPCs would be amplified. We show how the uncertainty of distance measurement varies with the relative error of DPCs. For our specific set of model parameters, without considering more complicated structures and kinematics of BLRs in our simulation, it is found that the relative error of DPCs < 20% is a limit for accurate distance measurement. The relative error of DPCs has a lower limit (roughly 5%) and the uncertainty in distance measurement can be better than 2%.

Aiming at the problem that the equipment maintenance support system is difficult to describe with highly stylized mathematical model, a framework model of equipment maintenance support agent is constructed. The paper introduces the Agent modeling method, analyzes the structure and workflow of the equipment maintenance support system, and abstracts the Agent framework structure according to the equipment maintenance guarantee and the modeling characteristics of the Agent. The internal modules of each Agent are designed and the agents are designed. The task environment between them has been studied, and the designed structural model can provide reference for other similar studies.

Remanufacturing plays a significant effect on saving social resources, developing green economy and reducing enterprise cost. Aiming at a production scheduling problem in manufacturing/remanufacturing hybrid systems we investigated, a multi-objective optimal scheduling model is built. The goals of optimization are to minimize total equipment idle time, total delivery delay and total setup time which are consistent with actual needs of the enterprise. An improved NSGA-II is adopted to increase the population diversity and improve the search performance. The similarity degree S is employed to evaluate the diversity of population in this paper. Crossover and mutation operations are adjusted adaptively based on S. This algorithm is applied to an engine manufacturing enterprise compared with the original genetic algorithm. The analysis of experimental results shows that the way in this paper has certain superiority.

In order to reveal the influence of the viscosity of the transmission oil on the braking performance of the hydraulic retarder, the change law of the viscosity of the hydraulic retarder at different temperatures is analysed, and the influence of the viscosity of the working medium on its braking performance is analysed. The results show that: low-viscosity transmission oil can increase braking torque.

This paper takes 3 construction machinery as the research object, uses the portable emission measurer (PEMS) to test the emission in the actual operation of construction machinery. And analyzes the relationship between the operating characteristics of construction machinery and the characteristics of NOx emission and CO emission. The research results show that the NOx emission of construction machinery is positively correlated with power, and the NOx emission change rate is positively correlated with the mechanical power change rate. There is no obvious correlation between the CO emissions of construction machinery and power, and the change rate of CO emissions is positively correlated with the rate of mechanical power change.

Large-scale in situ observations are sorely lacking, leading to poor understanding of nationwide atmospheric turbulence over China. Nevertheless, high-resolution soundings have become available starting in 2011, providing a unique opportunity to investigate turbulence across China. Here, we calculated the mean turbulence dissipation rate (ϵ) from radiosonde measurements across China for the period 2011–2018 using Thorpe analysis. The atmospheric layers that had stronger turbulence indicated by larger ϵ generally came with larger Thorpe length but with smaller Brunt–Väisälä frequency. Overall, the clear-air ϵ in the free atmosphere exhibited large spatial variability with a ‘south-high north-low’ pattern. Large clear-air ϵ values were observed in both the lower stratosphere (LS) and upper troposphere (UT), especially over the Tibetan Plateau (TP) and its neighboring regions with complex terrain likely due to large-amplitude mountain waves. Particularly, less frequent but more intense clear-air turbulence was observed in both lower troposphere (LT) and UT over the TP, while more frequent, less intense clear-air turbulence was found in northern China. The all-sky turbulence considering the moist-saturation effects was much stronger in the troposphere, notably in southern China where convective clouds and precipitation oftentimes dominated. In the vertical direction, the altitude of peak clear-air ϵ in the troposphere was found to decrease poleward, broadly consistent with the meridional gradient of tropopause height in the Northern Hemisphere. A double-peak mode stood out for the profiles of clear-air ϵ at midlatitudes to the north of 30° N in winter: one peak was at altitudes of 15–18 km, and another at altitudes of 5–8 km. The strong shear instabilities around the westerly jet stream could account for the vertical bimodal structures. The seasonality of ϵ was also pronounced, reaching maxima in summer and minima in winter. Our results may help understand and avoid clear-air turbulence, as related to aviation safety among other issues.

Original packaging design of Western Hubei Tujia is a handmade household item of Tujia people, and it is also a packaging container used to store, protect, and transfer living materials. The original ecological packaging origin, modelling materials, patterns, and colours of the Tujia nationality in western Hubei were reconstructed and sorted out under the guidance of sustainable design principles, from the perspective of sustainable design exploration and sustainable design continuation. These local materials were combined, in order to examine and interpret the spiritual significance and material function of the handmade packaging container. The prospects of development brought by the integration of the original ecological packaging of the Tujia family and modern design are explored, so that it further injects new life and energy into sustainable designs. While reflecting the advantages of original ecological packaging shape, material and rich ethnic elements, it focuses on the continuation and innovation of sustainable design of the Tujia native food packaging, promotes the ecological concept, develops sustainable packaging, and provides a creative space for Tujia family packaging design ideas.

Investigation of aerosol effects on fog with long-term measurements has generally focused on fog occurrence frequency and intensity; here we examine the effects on fog lifetime, fog formation, and fog dissipation. From analysis of 52 years (1960–2011) of data collected at 404 stations in China, it is found that fog lifetime exhibits a clear increasing trend with time, and the increased lifetime is mainly attributable to delayed fog dissipation. Increased aerosol levels and global warming affect fog lifetime in opposite ways; increased aerosol levels serve to prolong fog lifetime by primarily delaying fog dissipation, whereas warming decreases fog lifetime by primarily delaying fog formation. The overall aerosol effect on fog lifetime in China is shown to predominate, especially in the highly polluted region of Eastern China. The observational findings are confirmed by a suite of WRF-Chem simulations that reveal the influences of both increased aerosol levels and temperatures through a complex chain of interactions among microphysical, dynamical, thermodynamic, and radiative processes.

The current economic and social development and changes in internal and external environments have brought severe challenges to the operation of power grid companies. By studying the input-output relationship of all factors in power grid companies, from the perspective of effectiveness, efficiency, and benefit, this paper constructs an input-output evaluation index system, introduces analytic hierarchy process and entropy method for weight calculation, uses weighted average method to construct input-output evaluation model, and conducts empirical research with relevant data and information in a certain area as an example. The research results can provide auxiliary decision-making support for the scientific and reasonable allocation of resources, and realize the clarity of input and output effects of power grid enterprises, scientific and rational investment arrangements, and lean business management.

The research on the potential purchase behavior of users can help merchants develop better marketing strategies. At present, many research methods of online purchasing behavior are based on simple rule prediction, and the prediction results are not satisfactory. We design a hybrid model of Gradient Boosting Decision Tree and logistic regression to accurately predict the purchase behavior of users, which combines the association characteristics between users and commodities. Firstly, clustering algorithm and association rules are used to solve the problem of data imbalance and mine more potential related features. This scheme not only improves the processing efficiency of large data, but also solves the problem of user cold start. Secondly, we construct a scalable tree enhancement system (XGBoost) to train the initial feature set, which is a strong classifier composed of several weak classifiers. A new training set combines the new features with the original features through feature reconstruction, and a hybrid machine learning system is constructed by logistic regression (LR) model. Finally, the LR model is trained by the new training set. Compared with the existing schemes, the integrated decision tree model can train more sample sets with less resources. The experimental results show that the accuracy of the hybrid model is better than single model, and the F1_score is higher.

In this paper, four typical compounds of odorants were selected as the research objects. The mathematical model hypothesis is established which based on the Weber-Fechner law, and then the relationship between the concentration of odor substances and the odor grade is verified to judge whether this law is applicable to the objective evaluation of vehicle interior odor. The results show that: the concentration of single odor substance and odor grade, the concentration of two kinds of odor substances and odor grade are in accordance with this law. It is proved that the relationship between odor substance concentration and odor grade conforms to the law to a certain extent, which provides an important theoretical basis for objective evaluation of vehicle interior odor and control vehicle environment to create an environmental and healthy vehicle.

At present, there are many methods for data dimensionality reduction, but most of the results of decomposition methods allow negative values. Obviously, these negative values have no physical meaning in practical problems. The non-negative matrix factorization method is a dimensionality reduction under the condition of ensuring non-negative values. This paper mainly uses a non-negative matrix factorization algorithm to perform dimensionality reduction representation and local feature extraction of data, and then classify. Experiments show that the algorithm in this paper is reasonable and effective.

Incorporation of impurities in CuAlO2 provides an opportunities to modulate its electronic and optical properties, which can be exploited for the applications of optoelectronic devices. Among the various elements doped of CuAlO2, research on the codoping magnesium (Mg) with nitrogen (N) which may be a promising way for fabricating p-type CuAlO2 is still limited. Here, the first-principles calculation based on density functional theory was used to investigate the electronic and optical properties of Mg-doped, N-doped and Mg–N codoped CuAlO2. Compared with the undoped CuAlO2, the lattice parameters a and c of the Mg–N codoped CuAlO2 become larger and smaller, respectively. The acceptor level induced by 2p state of N in N-doped CuAlO2 is very deep. The undoped and Mg-doped CuAlO2 has indirect band gap. Whether the deep acceptor level or the indirect band gap, it is unfavorable to p-type doping or light emission. Due to the hybridization of 3p state of Mg and 2p state of N on the top of the valence band, the Mg–N codoped CuAlO2 not only has a direct band gap, but also has a shallower acceptor level (about 0.24 eV above the top of the valence band). The optical properties of CuAlO2 changes obviously after Mg–N codoping in the area of low energy. These results suggest that the possibility of enhancing the hole concentration in CuAlO2 by Mg–N dual-acceptor codoping which will be beneficial to the application of CuAlO2 in optoelectronic devices.

Under the context of digital new media, the paper deals with the composition and dissemination of Chinese character images from three perspectives: the structure and communication of the character images, the presentation of character images and the modes of communication. Due to the computer technologies, Chinese characters could be presented on the screen with both pictures and sounds and become more intuitive and realistic. What’s more, the light effects and dynamic technique feature prominent in forming visual images of Chinese characters. In a word, the computer technologies help to realize the multi-dimensional and dynamic presentation of Chinese characters.

Porous medium square pipelines with pellet packed bed and cylindrical packed bed are employed to experimentally study the flow characteristics of water. Differences of flow characteristics between the pellet packed bed and cylindrical packed bed, as well as the circular pipe and the square pipe, are discussed by measuring the pipeline pressure drop under different flow rate, and the relationship between the pipe resistance coefficient and flow is analyzed. The results show that the pressure drop per unit length in the square pipe increases with the increase of flow rate and increases with the decrease of pellet diameter. The structure of large diameter pellet packed bed is more advantageous to form a relatively stable flow.

To compare the effects of different surface treatment methods on the surface characteristics of yttria-stabilized tetragonal zirconia (Y-TZP) and relevant shear bond strength (SBS) between zirconia and composite resin. Forty-eight Y-TZP ceramics were randomly divided into four groups based on the specific surface treatments: Group C (blank treatment), Group Sand (sandblasting with 80 μm Al2O3 particles), Group HF (etched with 40% hydrofluoric acid for 10 min), and Group H2SO4 (etched with hot sulfuric acid for 10 min). Surface characteristics of the treated specimens, including morphology, roughness, wettability, chemical composition and crystalline structure were analyzed. SBS was tested by bonding ceramics to resin cement in the same group. Kruskal-Wallis test followed by pair wise comparison was conducted for statistical processing. A significance level of α = 0.05 was set. Three kinds of surface structures with different widths and heights in roughness were obtained, including micron-scale pit/peak size by sandblasting, nano-scale pit/peak size by hydrofluoric acid etching and middle submicron-scale pit/peak size by hot sulfuric acid etching. By comparison, the specimens of Group HF showed the most favorable wettability, the highest SBS and the lowest phase transformation than those of other groups. Therefore, HF etching was considered as a promising surface treatment to promote resin–zirconia bonding without excessive surface damage. The height, width, frequency and regularity of roughness altogether affected the shear strength.

The solar computer simulation technology has been extensively applied in the fields of polymer curing test, solar cell detection and calibration, and satellite heat balance test, etc. The non-negative least-squares solution of the overdetermined equations based on the non-dominated sorting genetic algorithm (NSGA) to optimize the monochromatic light-emitting diode (LED) matching light source combination, replace some monochromatic LED with white LED to simulate the solar spectrum, and discuss several LED lights with different peak wavelengths that can be replaced by white LED. The simulation results suggest that in the range of 300 ∼ 1100 nm, as the monochromatic LED types replaced by white LED increase, the total number of LEDs used is reduced, and the spectral match decreases. When LEDs with three different peak wavelengths are replaced, the correlation index in the fitting based on the algorithm is 0.9035, where the number of LEDs can be reduced by 15.6%, and the simulation spectrum is basically consistent with the target one. The proposed method has a small spectral mismatch and can be used to distinguish two absorption valleys of the standard solar spectrum AM1.5 accurately.

In view of the lack of efficiency evaluation index system of intelligent weapon system and insufficient quantification and refinement of technical indexes, the research on the index system will be carried out from the perspective of completing the task of intelligent weapon system, and the verification index system will be established to realize the evaluation of weapon system efficiency, clarify the use background of intelligent weapon system, and analyze the strength composition of intelligent weapon system, Finally, Delphi method is used to build the effectiveness evaluation index system of the intelligent weapon system, which can be used as a reference for the comprehensive evaluation of the capability of the weapon system. CLC number: TJ02 Document identification code: A

The effect of Sr and cooling rate on the microstructure of Al-2.5%Mn alloy was studied by OM, SEM and XRD. The results showed that Sr not only refined the primary phase, but also refined eutectic microstructures. However, there was obvious delamination in the alloy. When the content of Sr was 0.2%–0.65%, the primary phase in the upper part of alloy changed from coarse needle and lath-shaped to fine block and needle-like. With the Sr content increased, the needle-like structure in the alloy tended to be more and longer, but the size of α-Al tended to be finer. At the bottom, there were many large massive phases, which were much more refined than the primary phase without Sr With the cooling rate increased, the primary phase was refined greatly and almost all of them transformed into eutectic microstructure. Besides, the delamination of microstructure disappeared.

In order to improve the accuracy of photovoltaic power output prediction, a photovoltaic power prediction method based on similar days and improved artificial bee colony support vector machine is proposed. Firstly, through calculating the Euclidean distance of history day and measured day meteorological factors to determine similar days. Secondly, select historical data of photovoltaic power output, temperature, humidity and daily radiation on the slope of similar days and temperature, humidity and daily radiation on the slope of test date as input variables of support vector machine. And we adopt the improved artificial bees colony to optimize kernel function parameters and the penalty factor of support vector machine. Finally get the output in each period of photovoltaic power prediction. The experimental results showed that the proposed method can effectively improve the prediction accuracy of photovoltaic power.

Recently, the large number of labels challenges the traditional multi-label classification methods in various application scenes. We introduce a framework of multi-label classification based on Boolean matrix decomposition for giving various multi-label classifiers the ability to predict labels in a high dimension label space. The BMD module in this framework satisfies two conditions of ‘the column use condition’ and exacts BMD, which can reduce the burden on training and predicting task of multi-label classifier to some extent, and the predicted result of multi-label classifier can be restored to original label space by simply Boolean multiplying with matrix. Experimental results on yeast datasets demonstrate that our framework can work particularly well on datasets with a large number of labels and obtain a better predicting accuracy. In summary, the methods discussed in this paper constitute important basic for utilizing more multi-label classifiers in high label dimension space, which is the main contribution of this paper.