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Abstract Objectives Low‐dose computed tomography (LDCT) has emerged as a pivotal tool for detecting lung cancer among ever‐smokers. This study aims to evaluate the gender‐specific outcomes of LDCT screening within the Chinese never‐smoking population. Methods We conducted a single‐center, retrospective cohort study, which analyzed LDCT screening outcomes for 42,018 asymptomatic participants. Specifically, we focused on assessing gender‐specific differences in the prevalence of pulmonary nodules, and the incidence of lung cancer diagnosis among never‐smokers. Results Among the 42,018 eligible participants, 41.50% were females and 58.50% were males. Most participants were non‐smokers (77.57%), with a significantly higher proportion of non‐smokers among females than males (99.33% vs. 62.14%). Pulmonary nodules were identified in 2.66% of participants, with a higher prevalence in females (2.99%) than males (2.43%) (p

Accurate measuring magnetic induction intensity is important for some scientific research. In the paper, the conventional nuclear magnetic resonance (NMR) experiment under static magnetic field has been extended to longitudinal time-varying magnetic field (TVMF), and the time domain transient solution of the Bloch equations for spin nuclei exhibits the so-called non-steady state nuclear magnetic resonance (NSS-NMR) phenomenon. Based on the above effect and the precise gyromagnetic ratio of spin nucleus, a new magnetic field measurement method and corresponding experimental apparatus have been developed in longitudinal TVMF environment. The orthogonal dual-coil probe, radio frequency (RF) exciting and receiving hardware, key signal processing algorithms, host computer controlling and analysis software are deeply studied. In order to improve the signal-to-noise ratio of the NSS-NMR signal, the RF signal envelope shaping and the low-frequency pre-emphasis probe matching techniques are designed and verified by the invented circuit-field-nuclear multi-domain joint simulation subassembly (CFN-MDJS) which is integrated in the host computer software. Furthermore, the multi-tone RF excitation signal substituting the bandpass continuous spectrum signal for NSS-NMR experiment is also verified by the CFN-MDJS. The experimental results under longitudinal 50Hz TVMF environment has demonstrated the authentic existence of the NSS-NMR effect and simultaneously verified the effectiveness of the experimental scheme and signal processing algorithms proposed in the paper.

The development of high-speed aerial vehicles urgently requires high-performance integrated materials for ablation resistance, thermal insulation and oxidant protection under high temperature. The previously prepared carbon aerogel composites (C/CA), with ultra-high temperature thermal insulation properties, were impregnated with SiCO precursor sol and pyrolysed in nitrogen atmosphere at 1200°C. The impregnation/pyrolysis process was performed once, twice and thrice to obtain three different C/C-SiCO nanoporous ceramic composites. Further, TaSi2-MoSi2-borosilicate glass (TM-BG) coating or TaSi2-MoSi2-ZrB2-borosilicate glass (TMZBG) coating was prepared on the surface of the C/C-SiCO through slurry brushing combined with graphite powder embedded sintering process. By simulating the actual application environment through oxygen acetylene flame ablation test, the ablation resistance of the samples was studied and their oxidation mechanism was analysed. The results show that the ablation rate of the C/C-SiCO after 200 s ablation at 1600 °C decreases with the increase of the number of impregnation/pyrolysis steps and that the ablation resistance of the coating modified C/C-SiCO was significantly enhanced. The addition of ZrB2 to the coating improves the compatibility between the substrates and the coating, and the TMZ-BG coated sample has better ablation resistance. At high temperature, the borosilicate glass in the coating is in a viscous flow state. Meanwhile the SiO2 generated by the oxidation of other silicide raw materials forms a dense glass layer on the coating surface, which can be used as an oxygen barrier to provide better protection for the substrates. The coating-modified C/C-SiCO porous ceramic composites are expected to be used as a high-temperature ablation-resistant material for the thermal protection system of new aerospace vehicles.

To tackle the problem of difficult signal detection and carrier frequency synchronization faced by wireless communication among stations of the multistatic passive detection system in interference environments, an adaptive signal detection and carrier frequency offset (CFO) estimation method based on a virtual array is proposed in this paper. This is a data-aided method that utilizes a training sequence composed of three segments of sub-training sequences with different symbols. This method first uses spatial spectrum estimation to obtain the coarse frequency estimations of interference signals and CFO from virtual array signals constructed from the first two sub-training sequences. Then, beamforming is conducted accordingly on the virtual array signals constructed from the third sub-training sequence to suppress the in-band interferences and protrude the expected signal. Finally, improved performance of signal detection and CFO estimation is obtained with the beamformed signals. Simulation experiments show that a missed detection probability as low as 1 × 10−4, with a false detection probability of 1 × 10−3, can be obtained under a signal-to-interference ratio (SIR) of −10 dB and Eb/N0 of 1 dB. Moreover, the proposed method can also simultaneously achieve a CFO estimation error that is lower than 3%, with the condition of Eb/N0 being as low as −5 dB under different SIRs. Simulation results validate the proposed method and demonstrate the promising application prospects of the proposed method in networked passive detection scenarios.

How to enhance the desired signal with low signal-to-noise ratio (SNR) is a difficult problem in the estimation process of the direction-of-arrival (DOA) of the target scattering wave signal. In this paper, the feasibility of spatial spectrum estimation in the Range-Doppler (RD) domain is analyzed in principle, and the SNR gain expression of weak scattering wave signal is derived when constructing multi-snapshots virtual array data. On this basis, the mutual eigenvector singular value decomposition (MESVD) method based on RD domain mode excitation is proposed, which can robustly and effectively estimate the direction of the coherent weak signals. Simulation experiments verify that the RD domain spectral estimation method has the ability to simultaneously obtain the direction of multiple weak target scattering waves, and the direction-finding accuracy can reach the Cramer–Rao bound (CRB) of conventional spectral estimation method. The results of Monte Carlo experiments show that the root-mean-square-error (RMSE) of azimuth estimation of RD domain spatial spectrum estimation method is 5.76° lower than that of a conventional multiple signal classification (MUSIC) method. In addition, the practicability of the proposed method is demonstrated by comparing the DOA estimation results of a set of real data with Automatic Dependent Surveillance-Broadcast (ADS-B) data.

This paper analyzes the correlation between Civics teaching and student management in colleges and universities by establishing a multiple linear regression model to study the influence of Civics teaching on student management. Based on the questionnaire data, it analyzes the level of civics teaching and student management in 20 colleges and universities in City A. Based on the balanced panel data, it conducts benchmark regression analysis and dynamic panel analysis on the data of Civics education and student management and investigates the effect of the integration of college and university student management with the Civics teaching work. The results show that in the dynamic panel analysis, the estimated coefficients of the core explanatory variable of Civic and political education in each column are 0.028, 0.032, 0.033, 0.038, with positive significant coefficients, indicating that Civic and political education activities help to improve the level of management of students in regional colleges and universities. This study tests the positive influence of the integration of Civic and Political teaching work on student management and provides a certain reference value for colleges and universities to improve the level of student management.

In the fixed prosthesis process dental prosthesis treatment, the dentist needs to conceive the morphology of the tooth preparation and make numerous micro-adjustments by manual operation. This study aims to establish a digital design system for accurate designing of veneer preparation and study the trajectory planning of the robot-assisted preparation. According to the standard operation requirements, the projection line segmentation method based on point drawing is proposed for interactive selection to ensure the margin smoothness of the preparation area. The preparation depth is parameterized, and the foldback point correction method based on secondary segmentation is used for repairing the offset preparation area to ensure surface smoothness. The fenestration preparation model was obtained in the digital interactive design software. The model is divided into two feature areas which are interpolated by the B-spline curve and NURBS surface, respectively. The isoparametric curve method is used to plan the preparation trajectory. The experimental and theoretical values of the target feature points from the X, Y and Z coordinate directions were also calculated and analyzed. The experiment is carried out by the physical prototype of the tooth preparation robot. The maximum error of the feature points on the preparation are 0.180 mm, 0.104 mm and 0.142 mm in X, Y and Z directions, respectively. The confidence interval of the system error is stable within 0.30 mm. The error of the feature points verifies the feasibility of the digital interactive design system and the correctness of the trajectory planning of tooth veneer preparation. The system could have the potential to assist dentists in the precise design of the veneer preparation, improve the processing efficiency and ensure the effect of tooth veneer prosthesis.

C7H3AgCl2O3, monoclinic, P21/c (no. 14), a = 13.1492(5) Å, b = 3.72760(10) Å, c = 16.5625(6) Å, β = 92.1810(10)°, V = 811.22(5) Å3, Z = 4, R gt(F) = 0.0229, wR ref(F 2) = 0.0492, T = 301(2) K.

Compared with conventional monostatic or bistatic radar, multistatic radar has wider coverage, better performance of localization and higher tracking accuracy. However, the multistatic radar architecture poses challenges to the implementation for multitarget tracking in coping with highly uncertainty of data association for the fusion of multisource information. In this paper, the theoretically rigorous formulas for the multisource multi-Bernoulli (MeMBer) filter are derived by using the Finite set statistics (FISST) calculus built on the standard MeMBer filter. The multisource MeMBer filter propagates a set of MeMBer parameters approximately characterizing the multisource corrected posterior multitarget random finite set (RFS). Since the equations for the proposed filter multisource corrector are computationally intractable, we go further to develop an analytic Sequential Monte Carlo (SMC) implementation of multisource MeMBer recursion. The theoretical analysis and simulations show that the proposed filter performs well and accommodates nonlinear multistatic radar tracking scenario with a single transmitter and two receivers under the approximate conditions.

Mn-Ce catalysts modified by Mo were loaded on low-density porous ceramics (LDPC) for simultaneous denitrification and dust removal. The Mn-Ce-Mo catalyst on LDPC had nearly 99% NOx conversion efficiency from 120 °C to 200 °C and still maintained more than 90% NOx conversion efficiency when the filtration velocity reached to 4 m/min. Mn-Ce-Mo catalysts/LDPC not only exhibited excellent catalytic performance at low temperature, they also exhibited good resistance to H2O and SO2. The NOx conversion efficiency remained above 89% at 160 °C when the flue gas contained 100 ppm SO2 and 7 vol.% H2O. The analysis of NH3-TPD and XPS confirmed that Mn2Ce1Ox catalysts modified with Mo had the stronger surface acidity and more adsorbed oxygen, leading to higher NH3-SCR activity and better resistance to SO2 and H2O.

A novel approach to evaporate brine wastewater using a ceramic aeration membrane was proposed. A high-porosity ceramic membrane was selected as the aeration membrane and was modified with hydrophobic modifiers to avoid undesired surface wetting. The water contact angle of the ceramic aeration membrane reached 130° after hydrophobic modification. The hydrophobic ceramic aeration membrane showed excellent operational stability (up to 100 h), high salinity (25 wt.%) tolerance, and excellent regeneration performance. The evaporative rate reached 98 kg m−2 h−1, which could be restored by ultrasonic cleaning after the membrane fouling occurred. Furthermore, this novel approach shows great promise for practical applications toward a low cost of only 66 kW·h·m−3.

BACKGROUND The main types of copper deposits are porphyry and skarn types. Dacite porphyry is a rock type commonly developed in the porphyry Cu-Mo-Au system. The rock can be used as a marker clue for ore prospecting and ore-forming rock when there is well-developed hydrothermal alteration. The Dabaoshan deposit is currently the largest copper polymetallic deposit in the South China Block. Previous studies have shown that the dacite porphyry of the mining area is not only the ore-forming parent rock, but also a favorable ore-bearing wall rock. However, there are some debates about the relationship between dacite porphyry and mineralization in this mining area. With the breakthrough of prospecting for medium and large dacite porphyry ore bodies in recent years, the relationship between dacite porphyry and mineralization has once again become a concern. OBJECTIVES To understand the relationship between dacite porphyry alteration and mineralization of the Dabaoshan deposit. METHODS Based on field work and indoor analysis, X-ray fluorescence spectroscopy (XRF) and inductively coupled plasma-mass spectrometry (ICP-MS) were used to determine copper, tungsten, silicon, aluminum and calcium in Dabaoshan dacite porphyry samples. The isotope composition, metal element contents and alteration characteristics of the dacite porphyry in the mining area were used to discuss the relationship between alteration and prospecting direction. RESULTS The copper content ranged from 107 to 6909μg/g, which was consistent with the copper ore grade of 0.3%-0.5% in the mining area. The LOI and other geochemical indicators that can represent the degree of alteration were positively correlated with copper. Hydrothermal alteration was widely developed in dacite porphyry, including potassium, prophyliticition and quartz-sericitization from early to late stage. Among different stages of alterations, the copper content of quartz-sericitization was 2 to 5 times higher than other alteration types, indicating that quartz-sericitization was closely related to copper mineralization and was an important prospecting marker clue. CONCLUSIONS The deep alteration intensity of the dacite porphyry (below the 270m elevation) has not been weakened, suggesting a great prospecting potential. In addition, the contact zone between dacite porphyry and the Jurassic strata, and the xenoliths in the dacite porphyry are also important prospecting directions, which may host skarn-type copper-rich deposits.

Aiming at problem that opening of water plug-in gate valve in coal preparation plant needs manual adjustment and cannot achieve centralized control, a line laser assisted visual monitoring method for opening of water plug-in gate valve in coal preparation plant was proposed. Line laser is used as an auxiliary detection means to increase target detection characteristics and avoid influence of light changes on target detection, and video monitoring system is used to collect plug-in gate valve image. Template matching method is used to locate target in the image, adaptive threshold method is used to detect line laser projected on the gate, and then adjacent disconnected areas of the line laser on the gate are connected through morphological operations such as corrosion, expansion and so on. Meanwhile, Gaussian filtering method is adopted to remove image noise, so position and length of the line laser in the image are obtained to detect opening of plug-in gate valve. PLC centralized control system realizes closed-loop control of opening of plug-in gate valve by comparing the detected opening value and the set one. The experimental results show that the method can accurately locate plug-in gate valve under different background brightness conditions, and improve detection accuracy of opening of plug-in gate valve.

The measurement of a time-varying magnetic field is different from a constant magnetic field, due to its field intensity variation with time. Usually, the time-varying magnetic field measurement converts the solution of the magnetic induction intensity into the calculation of the induced electromotive force (EMF); then, the magnetic induction intensity is obtained by the time integration of the EMF, but the process is vulnerable to external interference. In this paper, a non-steady state nuclear magnetic resonance (NSS-NMR) scheme for the measurement of a time-varying magnetic field is proposed. In a time-varying magnetic field environment, an RF excitation signal with a certain frequency bandwidth is applied to excite the nuclear spin system. The NSS-NMR signal, which varies with time in the frequency range corresponding to the frequency bandwidth of the RF excitation, could finally be obtained after a series of processing of the probe output signal. During the NSS-NMR experiment, an orthogonal dual-coil probe is adopted to synchronously generate the RF excitation and induce the probe output signal. Moreover, a directional coupler that utilized in the experiment outputs a reference signal from the coupling port for the subsequent signal processing. The experimental results show that the weak NSS-NMR signal is indeed observed. The longitudinal time-varying magnetic field ranges from 0.576 T to 0.582 T, which is inverted by the Larmor precession relationship, have been successfully detected based on the so-called NSS-NMR effect.

C26H24N3O3SAg, monoclinic, P21/c (no. 14), a = 13.1936(9) Å, b = 11.0544(7) Å, c = 16.3653(9) Å, β = 99.214(6)°, V = 2356.0(3) Å3, Z = 4, Rgt(F) = 0.0495, wRref(F2) = 0.1080, T = 293(2) K.

C40H42Mo5N8O23P2, triclinic, P1̄ (no. 2), a = 10.9867(2) Å, b = 15.4753(3) Å, c = 15.5666(3) Å, α = 85.583(2)°, β = 81.294(2)°, γ = 84.844(2)°, V = 2600.18(9) Å3, Z = 2, Rgt(F) = 0.0208, wRref(F2) = 0.0485, T = 293(2) K.

C36H52Ag2N10O8S2, orthorhombic, Pna21 (no. 33), a = 11.7911(16) Å, b = 31.310(5) Å, c = 10.6883(11) Å, V = 3945.9(9) Å3, Z = 4, Rgt(F) = 0.0353, wRref(F2) = 0.0784, T = 293(2) K.

C44H44Ag2N6O8S2, triclinic, P1̄ (no. 2), a = 11.3967(5) Å, b = 12.6953(6) Å, c = 14.9539(7) Å, α = 80.903(4)°, β = 89.801(4)°, γ = 83.911(4)°, V = 2124.14(17) Å3, Z = 2, Rgt(F) = 0.0421, wRref(F2) = 0.1130, T = 293(2) K.

Pure and Ni-doped Zn1-xNixFe2O4 nanoparticles with different contents were successfully prepared via hydrothermal method. The influence of nickel doping concentration on the microstructure, morphology, optical and magnetic properties of Zn1-xNixFe2O4(x=0,0.1,0.3,0.5) nanocrystals were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction(SAED), X-ray energy dispersive spectroscopy(XEDS),ultraviolet-visible absorption spectrum(UV-Vis), Fourier transform infrared spectroscopy (FT-IR) and the vibrating sample magnetometer (VSM) and etc. The results show that all Zn1-xNixFe2O4 nanoparticles are with good crystallization,Ni2+ enters into ZnFe2O4 lattice in the form of replacing Zn2+,and generating cubic spinel structure ZnFe2O4. With the increase of Ni content, the crystalline size increases and the lattice constant shrinks. The morphology of the samples exhibits irregular ellipsoid with uniform particle size. The absorption peak position of FT-IR spectra does not change with the increase of Ni doping concentration. The energy band gap of Zn1-xNixFe2O4 nanocrystals increases with the increase of Ni doping concentration, and blue shift occurs compared with the corresponding bulk. Pure ZnFe2O4 nanocrystals exhibit super paramagnetic properties and the doped samples show obvious ferromagnetism at room temperature.

The maximum load of wing and fuselage increases sharply while flapping-wing micro air vehicles(FWMAVS) flutters at high frequencies, which seriously affect the flight performance and flight life. The mathematical models of wing lift, drag and inertial forces during the FWMAVs fluttering are established, based on the analysis of movement and force conditions of the wing. A multi-objective optimization model targeting at improving the distribution of loads in the time domain is then proposed and solved by using NSGA-Ⅱ algorithm in Matlab environment. After all the work, the Pareto optimal solution set of the hovering state is obtained. Comparison and analysis of the data show that after the optimization, the peaks of lift and inertial forces decline significantly and the load distribution is obviously improved.

C25H29Ag2N5O9S, monoclinic, P21/m (no. 11), a = 8.5437(16) Å, b = 17.852(4) Å, c = 9.3335(13) Å, β = 101.380(16)°, V = 1395.6(5) Å3, Z = 2, Rgt(F) = 0.0271, wRref(F2) = 0.0653, T = 293(2) K.

A simple and efficient method is explored for the synthesis of 2-hydroxyimino-2-phenylacetonitriles (2) and phthalimides (4), by using nitromethane as nitrogen donors. Both reactions are promoted by Cu(II) system with the participation of dioxygen as an oxidant. The scope of the method has been successfully demonstrated with a total of 51 examples. The flexible and diversified characteristics of reactions are introduced in terms of electronic effect, steric effect, position of substituted groups, and intramolecular charge transfer. Experimental studies suggest that the methyl nitrite could be a precursor in the path to the final products. A possible reaction mechanism is proposed, including the Cu(II)/O2-facilitated transformation of nitromethane to methyl nitrite, the base-induced formation of 2-hydroxyimino-2-phenylacetonitriles, and the base-dioxygen-promoted formation of phthalimides.

Triple perovskite has been recently developed for the intermediate temperature solid oxide fuel cell (IT-SOFC). The performance of Nd1.5Ba1.5CoFeMnO9−δ (NBCFM) cathodes for IT-SOFC is investigated in this work. The interfacial polarization resistance (RP) of NBCFM is 1.1273 Ω cm2~0.1587 Ω cm2 in the range of 700–800 °C, showing good electrochemical performance. The linear thermal expansion coefficient of NBCFM is 17.40 × 10−6 K−1 at 40–800 °C, which is significantly higher than that of the electrolyte. In order to further improve the electrochemical performance and reduce the thermal expansion coefficient (TEC) of NBCFM, Ce0.8Sm0.2O2−δ (SDC) is mixed with NBCFM to prepare an NBCFM-xSDC composite cathode (x = 0, 10, 20, 30, 40 wt.%). The thermal expansion coefficient decreases monotonically from 17.40 × 10−6 K−1 to 15.25 × 10−6 K−1. The surface oxygen exchange coefficient of NBCFM-xSDC at a given temperature increases from 10−4 to 10−3 cm s−1 over the po2 range from 0.01 to 0.09 atm, exhibiting fast surface exchange kinetics. The area specific resistance (ASR) of NBCFM-30%SDC is 0.06575 Ω cm2 at 800 °C, which is only 41% of the ASR value of NBCFM (0.15872 Ω cm2). The outstanding performance indicates the feasibility of NBCFM-30% SDC as an IT-SOFC cathode material. This study provides a promising strategy for designing high-performance composite cathodes for SOFCs based on triple perovskite structures.

The catalyst particles were removed from fluid catalytic cracking (FCC) slurry oil by two-step separation processing. FCC slurry oil was mixed with water and surfactant to make the lower viscosity emulsion. The catalyst particles were removed from the emulsion using the modified hydrophobic ceramic membrane (0.1 μ m) and then the water was filtered out from oil/water emulsion using an unmodified hydrophilic ceramic membrane (0.05 μ m) at room temperature. The separation efficiency of catalyst particles and emulsion reached 99.9% and the oil/water separation efficiency also reached 99.9%. FCC slurry oil was effectively purified at room temperature by a two-step treatment.

Abstract Water–sand flow triggered by rainfall is the dominant mechanism for instability and failure of sand slopes. To further analyze the stability state of sand on a slope under different rainfall conditions, the initiation conditions and flow characteristics of water–sand flows are studied. Based on the theory of equilibrium forces and hydrological dynamics, a 1:100-scale analog model is built and verified with field observation data. The results indicate three dynamic stabilization stages of the sand slope under different weather conditions: dry sand, wet sand, and water–sand flow. Water–sand flows are triggered easily under short duration and heavy rainfall conditions. The rainfall threshold required to initiate water–sand flow is 4.14 mm/h. Rainfall amount and duration required to initiate water–sand flow decrease with fine sand content increasing. A sand head that develops at the front of the water–sand flow results in a flow along the edge of the sand debris flow and a “tree root” flow morphology. Modeling results are consistent with theoretical analysis and field observations.

C7H8Ag2N3O4S, triclinic, P1‾$‾{1}$ (no. 2), a = 7.3758(3) Å, b = 8.7361(4) Å, c = 9.2906(4) Å, α = 112.877(4)°, β = 90.054(4)°, γ = 102.568(4)°, V = 535.90(4) Å3, Z = 2, Rgt(F) = 0.0235, wRref(F2) = 0.0600, T = 293(2) K.

C12H18O8N4S2Ag2, monoclinic, P21/c (no. 14), a = 10.7841(10) Å, b = 8.0140(5) Å, c = 11.7220(11) Å, β = 117.278(11)°, V = 900.40(16) Å3, Z = 2, Rgt(F) = 0.0279, wRref(F2) = 0.0627, T = 293(2) K.

Diluted magnetic semiconductors Zn1-xMnxS with different consistency (x=0.00, 0.02, 0.05, 0.07) were synthesized by hydrothermal method, and the effects of doping concentration Mn2+ on the microstructure and optical properties of ZnS nanorods were investigated. The crystal microstructure,morphology and optical properties of the products were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), corresponding selected-area electron diffraction (SAED), X-ray energy dispersive spectrometry (XEDS) and ultraviolet-visible spectrophotometer(UV-vis).The results show that all samples synthesized by this method possess wurtzite structure with good crystallization, no other impurity phase appears and generates single-phase Zn1-xMnxS nanocrystalline. The morphology of the samples is nanorods and well disperses. The doping element of Mn enters into the ZnS nanocrystals, Mn2+ replaces Zn2+, and the lattice constant decreases with the increase of Mn content. Meanwhile, the optical band gap increases and the blue shift occurs for the sample in the UV-vis spectra.

C12H30Ag2N4O11S2, monoclinic, I2/a (no. 15), a = 12.2643(8) Å, b = 7.1481(4) Å, c = 26.2858(16) Å, β = 93.119(6)°, V = 2301.0(2) Å3, Z = 4, Rgt(F) = 0.0186, wRref(F2) = 0.0462, T = 298(2) K.