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The ability to synchronize the satellite signals affects the navigation performance. Only after a procedure of acquisition, namely coarse synchronization, the data information needed to position can be extracted from the satellite signals. Conventional acquisition methods rely on extending the signal integration time to improve the correlation quality of the signal. However, extending the coherent integration time results in a large computational burden, which is unrealistic for civilian receivers. In this paper, we try to optimize the computational effort in the satellite navigation signal acquisition phase and propose an algorithm based on the mean value recognition convolutional neural network. The matrix with a high mean value is separated by the convolutional neural network, and then the Doppler shift and code phase from the matrix with a high mean value is introduced, which can effectively change the computation to 1/4338 of the original one. The trained model of the neural network can be embedded into the receiver directly, which has important engineering applications.

Background Spread through air space (STAS) is a novel invasive pattern of lung adenocarcinoma and is also a risk factor for recurrence and worse prognosis of lung adenocarcinoma. This study aimed to develop and validate a computed tomography (CT)-based logistic regression model to predict STAS in lung adenocarcinoma. Methods This retrospective study was approved by the institutional review board of two centers and included 578 patients (462 from center I and 116 from center II) with pathologically confirmed lung adenocarcinoma. STAS was identified from 90 center I patients (19.5%) and 28 center II patients (24.1%) from. The maximum diameter, nodule area, and area of solid components in part-solid nodules were measured. Twenty-one semantic characteristics were assessed. Univariate analysis was used to select CT characteristics, which were associated with STAS in the patient cohort of center I. Multivariable logistic regression was used to develop a CT characteristics-based model on those variables with statistical significance. The model was validated in the validation cohort and then tested in the external test cohort (patients from center II). The diagnostic performance of the model was measured by area under the curve (AUC) of receiver operating characteristic (ROC). Results At univariate analysis, age and 11 CT characteristics, including the maximum diameter of the tumor, the maximum area of the tumor, the area and ratio of the solid component, nodule type, pleural thickening, pleural retraction, mediastinal lymph node enlargement, vascular cluster sign, and lobulation, specula were found to be significantly associated with STAS. The optimal logistic regression model included age, maximum diameter and ratio of solid component with odds ratio (OR) value of 0.967 (95% CI: 0.944-0.988), 1.027 (95% CI: 1.008-1.046) and 5.14 (95% CI: 2.180-13.321), respectively. This model achieved an AUC of 0.801 (95% CI: 0.709-0.892) and 0.692 (95% CI: 0.518-0.866) in the validation cohort and the external test cohort, respectively. The difference was not statistically significant (P=0.280). Conclusions CT-based logistic regression machine learning model could preoperatively predict STAS in lung adenocarcinoma with excellent diagnosis performance, which could be supplementary to routine CT interpretation.

The transformation of liquid–solid interface induced by the steady magnetic field (SMF) in the directionally solidified Ni-10 wt pct Cr alloy was studied experimentally. At the moderate pulling rate (50 μm s−1), it could be observed that the interface morphology gradually transformed from planar to cellular shape with increasing the SMF intensity (0 T, 3 T, 6 T). However, the cellular interface at the high pulling rate (100 μm s−1) was not influenced by the SMF. 3D numerical simulations suggested that the transformation of interface morphology originated from the thermoelectric magnetic convection near the wavelike interface at the early stage of solidification. From the composition measurement, it was found that the formation of microsegregation at the moderate pulling rate was associated with the interface morphology. Under the 3 T SMF, the liquid–solid interface remained planar and the microsegregation level increased in comparison with that without the SMF. Under the 6 T SMF, the liquid–solid interface became cellular and the microsegregation level was reduced. The factors affecting microsegregation were evaluated. The effective partition coefficient was estimated based on composition data. It was revealed that the effective partition coefficient increased with the 6 T SMF due to the thermoelectric magnetic and magnetic damping effects within the cellular structure. Additionally, the solid diffusivity was measured using the diffusion couple technique. It was found that the interdiffusion coefficient of Cr decreased with increasing the SMF intensity. The modified Brody model was used to predict the microsegregation behavior in the SMF. The predicted results were in agreement with experimental observation. It could be concluded that the decrease in solid diffusivity enhanced the formation of microsegregation for the planar interface, whereas the increase in effective partition coefficient in the SMF was beneficial for alleviating the extent of microsegregation for the cellular interface.

The grain refinement of 2024 Al alloy inoculated with Al-5Ti-1B master alloy in a steady magnetic field (SMF) was investigated. It was shown that the degradation in grain refinement was enhanced and a cellular–dendritic transition of equiaxed primary α-Al grains occurred under the SMF. Employing a differential scanning calorimeter, the nucleation temperature of primary α-Al phase was found to decrease in the SMF, i.e., the undercooling was enhanced, and the kinetics of phase transformation was modified in the SMF. The enhanced degradation in grain refinement and increase in undercooling are attributed to the modified solid/liquid interfacial free energy and the delay of formation of critical nucleus due to the retarded migration rate of atoms in the liquid phase in the SMF. The cellular–dendritic transition of primary α-Al grains is ascribed to the modified constitutional undercooling at the solid/liquid interface, which results from the change in solute distribution by the damped convection and retarded diffusivity in the SMF. Additionally, the increase in growth dimension and the modified solid/liquid interfacial free energy under the SMF are also responsible for the enhanced constitutional undercooling and the cellular–dendritic transition.

Since the promulgation of the first school education regulations in the early 20th century, Chinese school aesthetic education has gone through its first century of history. Six stages of development have been formed in this century of vicissitudes, namely, the budding period, the starting period, the salvation movement period, the tortuous development period, the reconstruction period, and the modernization period of the new era. From a historical point of view, we can sort out and analyze the policies of school aesthetic education, and we can learn that Chinese school aesthetic education has always insisted on the direction of building socialism with Chinese characteristics, guided by the principles of Marxist aesthetics and the achievements of specific Chinese practice as the methodology, adhered to the direction of cultural development of socialism with Chinese characteristics, and aimed at cultivating qualified builders and successors for the comprehensive development of socialism with Chinese characteristics. Aesthetic education in Chinese schools places a prominent place on “establishing, cultivating and clarifying morality”, emphasizes the role of “beauty” in “goodness”, and follows the aesthetic guideline of “unity of beauty and goodness”. Art education and its practical activities are the main content of school aesthetic education. The formation mechanism, laws, and characteristics of the sustainable development of school aesthetic education in China are summarized from the perspective of the century-old school aesthetic education policy, which is of theoretical guidance for the study of the future development of school aesthetic education in China.

The effect of hot isostatic pressing on the tensile property of single crystal superalloys at elevated temperature is studied experimentally. The results show that the high temperature elongation of nickel based single crystal superalloys is obviously enhanced by hot isostatic pressing, while the yield strength is unchanged. Besides, it is found that the hot isostatic pressing causes the change of fracture surface. The enhancement of elongation and the change of fracture behavior are discussed.

The thermal and numerical simulation of the mould electromagnetic stirring (M-EMS) during continuous casting (CC) of the GCr15 bearing steel was performed. The thermal simulation apparatus ...

Experimental investigations on microsegregation during directional solidification of two Al–Cu alloys with and without a steady magnetic field (SMF) were carried out. The solidification morphologies and microsegregation behaviors were examined. The amount of non-equilibrium eutectics and the concentration versus solid fraction profiles were obtained. The results indicated that the amount of microsegregation was increased under an SMF when the solid/liquid interface was planar. For cellular and dendritic growth, however, the SMF alleviated the microsegregation level. The change of the factors affecting microsegregation under the SMF was analyzed. The reduction in solid diffusion coefficient in an SMF aggravated the microsegregation level, while the thermoelectric magnetic convection (TEMC) was found to have a positive effect. It was concluded that the change in microsegregation in different conditions might be attributed to the combined action of solid diffusion suppression and TEMC in mushy zone under an SMF. Based on Brody model, the microsegregation behavior in an SMF was predicted. The calculated results were in agreement with experiment observations.

The microsegregation behavior of the Al-4.5 wt%Cu alloy solidified at different cooling rates under the alternating magnetic field (AMF) was investigated. The experimental results showed that the amount of non-equilibrium eutectics in the interdendritic region decreased upon applying the AMF at the same cooling rate. The change in microsegregation could be explained quantificationally by the modifications of dendritic coarsening, solid-state back diffusion and convection in the AMF. The enhanced diffusivity in the solid owing to the AMF was beneficial for the improvement in microsegregation compared to the cases without an AMF. In contrast, the enhanced dendritic coarsening and forced convection in the AMF were found to aggravate the microsegregation level. Considering the contributions of the changes in above factors, an increase in solid diffusivity was found to be primarily responsible for the reduced microsegregation in the AMF. In addition, the microsegregation in the AMF was modeled using the analytical model developed by Voller. The calculated and experimental results were in reasonable agreement.

The effects of forced flows at different velocities on microstructure and solute distribution during the directional solidification of Sn-10 wt% Bi alloys under a simultaneous imposition of a transverse static magnetic field (TSMF) and an external direct current (DC) have been investigated experimentally and numerically. The experimental results show that the solid-liquid interface will gradually become sloping with the increase of the forced flow velocity when the thermoelectric magnetic convection (TEMC) dominates the forced flow at solidification front. However, the interface will gradually become planar as the flow velocity further increases when the electromagnetic convection (EMC) dominates the forced flow. Moreover, when the flow velocity gradually increases, the primary dendrite spacing decreases from 384 to 105 μm accordingly. The simulation results show that the solute distribution at the two sides of the sample can be significantly changed by the forced flow at solidification front. The rejected solute will be unidirectionally transported to one side of the sample along the TEMC (a low-velocity forced flow), thereby causing the formation of a sloping interface. However, the rejected solute will be returned back along the EMC (a higher-velocity force flow), which results in a planar interface. Furthermore, the solute content at the two sides of the sample under the forced flows at different velocities was measured. The results are in good agreement with the simulation results, which shows that the solute content difference between the two sides of the sample reaches the maximum when a 0.5 T TSMF is applied, while the solute content difference decreases to zero with a simultaneous application of a 0.5 T TSMF and a 1.6 × 105 A/m2 external DC.

The formation of the microstructures in the hypo- and hypereutectic Al Cu alloys in the steady magnetic field (SMF) was investigated using the conventional quenching technique. In comparison with quenched structures without the SMF, the additional bulky phases, i.e. θ-Al2Cu phase and the supersaturated α solid solution, were found to form in the Al-26 wt%Cu and Al-45 wt%Cu alloys quenched in the SMF, respectively. The temperature measurements showed that the maximum cooling rate of the quenched sample in the SMF was markedly higher than that without the SMF and thus a larger undercooling was obtained in the SMF. The microstructure formation in the SMF can be rationalized using the Al Al2Cu phase diagram with metastable extensions and the coupled growth zone.