2024

• Record 73 of
  
  Title:Studying the Effects and Competitive Mechanisms of YOYO-1 on the Binding Characteristics of DOX and DNA Molecules Based on Surface-Enhanced Raman Spectroscopy and Molecular Docking Techniques
  
  Author(s):Li, Yanjie; Li, Zhiwei; Yun, Penglun; Sun, Dan; Niu, Yong; Yao, Baoli; Wang, Kaige
  Source: INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES  Volume: 25  Issue: 7  DOI: 10.3390/ijms25073804  Published: 2024  
  Abstract:Revealing the interaction mechanisms between anticancer drugs and target DNA molecules at the single-molecule level is a hot research topic in the interdisciplinary fields of biophysical chemistry and pharmaceutical engineering. When fluorescence imaging technology is employed to carry out this kind of research, a knotty problem due to fluorescent dye molecules and drug molecules acting on a DNA molecule simultaneously is encountered. In this paper, based on self-made novel solid active substrates NpAA/(ZnO-ZnCl2)/AuNPs, we use a surface-enhanced Raman spectroscopy method, inverted fluorescence microscope technology, and a molecular docking method to investigate the action of the fluorescent dye YOYO-1 and the drug DOX on calf thymus DNA (ctDNA) molecules and the influencing effects and competitive relationships of YOYO-1 on the binding properties of the ctDNA-DOX complex. The interaction sites and modes of action between the YOYO-1 and the ctDNA-DOX complex are systematically examined, and the DOX with the ctDNA-YOYO-1 are compared, and the impact of YOYO-1 on the stability of the ctDNA-DOX complex and the competitive mechanism between DOX and YOYO-1 acting with DNA molecules are elucidated. This study has helpful experimental guidance and a theoretical foundation to expound the mechanism of interaction between drugs and biomolecules at the single-molecule level.
  Accession Number: 3804
  ISSN: 1661-6596
  eISSN: 1422-0067
• Record 74 of
  
  Title:Observation of the colliding process of plasma jets in the double-cone ignition scheme using an x-ray streak camera
  
  Author(s):Liu, Zhengdong; Wu, Fuyuan; Zhang, Yapeng; Yuan, Xiaohui; Zhang, Zhe; Xu, Xiangyan; Xue, Yanhua; Tian, Jinshou; Zhong, Jiayong; Zhang, Jie
  Source: PHYSICS OF PLASMAS  Volume: 31  Issue: 4  DOI: 10.1063/5.0188056  Published: 2024  
  Abstract:The double-cone ignition scheme is a novel approach with the potential to achieve a high gain fusion with a relatively smaller drive laser energy. To optimize the colliding process of the plasma jets formed by the CHCl/CD shells embedded in the gold cones, an x-ray streak camera was used to capture the spontaneous x-ray emission from the CHCl and CD plasma jets. High-density plasma jets with a velocity of 220 +/- 25 km/s are observed to collide and stagnate, forming an isochoric plasma with sharp ends. During the head-on colliding process, the self-emission intensity nonlinearly increases because of the rapid increase in the density and temperature of the plasma jets. The CD colliding plasma exhibited stronger self-emission due to its faster implosion process. These experimental findings effectively agree with the two-dimensional fluid simulations.
  Accession Number: 42704
  ISSN: 1070-664X
  eISSN: 1089-7674
• Record 75 of
  
  Title:Radiative Transfer Characteristics of the 1.27 μm O2 (a1 Δg) Airglow in Limb-Viewing
  
  Author(s):Wang Dao-qi; Wang Hou-mao; He Wei-wei; Hu Xiang-rui; Li Juan; Li Fa-quan; Wu Kui-jun
  Source: SPECTROSCOPY AND SPECTRAL ANALYSIS  Volume: 44  Issue: 4  DOI: 10.3964/j.issn.1000-0593(2024)04-1088-10  Published: 2024  
  Abstract:Because the 1.27 mu m O-2 (a(1) Delta(g)) airglow radiation has the advantages of strong radiation signal, large space span and weak self-absorption effect, it is an important target source for near-space atmospheric remote sensing. In addition, it has important scientific significance and application value, such as research on the dynamics and thermal characteristics of the middle and upper atmosphere, global greenhouse gas detection, and three-dimensional tomography of ozone concentration. Firstly, based on the photochemical model of O-2 (a(1) Delta(g)), the generation and annihilation mechanisms of O-2 (a(1) Delta(g)) airglow were studied. The volume emission rate profile of O-2 (a(1) Delta(g)) airglow was calculated on this basis. Based on the spectral intensity and Einstein coefficients given by HITRAN, two methods for calculating the spectral distribution of O-2 (a(1) Delta(g)) airglow were proposed. Using the latest molecular spectral parameters, photochemical reaction rate constant and F10.7 solar ultraviolet flux, combined with the volume emission rate profile information of O-2 (a(1) Delta(g)) airglow calculated by photochemical reaction model. The radiative transfer theoretical model of the 1.27 mu m O-2 (a(1) Delta(g)) airglow in limb-viewing was developed by using a line-by-line integration algorithm. The influence of the self-absorption effect on the spectral intensity of airglow radiation at different tangent heights is analyzed. Then, the O-2 (a(1) Delta(g)) airglow radiation spectrum of the target layer is obtained by processing the airglow radiation of the O-2 molecule near the infrared atmospheric band measured by scanning imaging absorption spectrometer for atmospheric chartography (SCIAMACHY) under the limb-viewing by onion peeling algorithm. Spectral integration algorithm is used to retrieve the volume emission rate profile of O-2 (a(1) Delta(g)) airglow. Finally, the reliability and rationality of the radiative transfer theoretical model of the 1.27 mu m O-2 (a(1) Delta(g)) airglow in limb-viewing is verified by comparing the radiation spectrum and the volume emission rate profile obtained from the theoretical calculation and retrieval of the SCIAMACHY instrument. Regarding the comparison results, factors that contribute to the limb radiation intensity and volume emission rate of O-2 (a(1) Delta(g)) airglow are analyzed. Analyses show that theoretical calculations agree with measured satellite results in the altitude region above 50 km. However, the deviation between the two increases gradually with the decrease of altitude because the satellite remote sensing in the middle and low altitude regions are seriously affected by the self-absorption effect and atmospheric scattering effect in limb-viewing. Additionally, compared with the spectral line intensity parameter given by the HITRAN database, the O-2 (a(1) Delta(g)) airglow limb radiation model based on Einstein coefficients is more consistent with the measured satellite results. Establishing the radiative transfer theoretical model of the 1. 27 mu m O-2 (a(1) Delta(g)) airglow in limb-viewing provides a theoretical foundation for atmospheric remote sensing in near space.
  Accession Number:
  ISSN: 1000-0593
  eISSN:
• Record 76 of
  
  Title:Fusion of Hyperspectral and Multispectral Images with Radiance Extreme Area Compensation
  
  Author(s):Wang, Yihao; Chen, Jianyu; Mou, Xuanqin; Chen, Tieqiao; Chen, Junyu; Liu, Jia; Feng, Xiangpeng; Li, Haiwei; Zhang, Geng; Wang, Shuang; Li, Siyuan; Liu, Yupeng
  Source: REMOTE SENSING  Volume: 16  Issue: 7  DOI: 10.3390/rs16071248  Published: 2024  
  Abstract:Although the fusion of multispectral (MS) and hyperspectral (HS) images in remote sensing has become relatively mature, and different types of fusion methods have their own characteristics in terms of fusion effect, data dependency, and computational efficiency, few studies have focused on the impact of radiance extreme areas, which widely exist in real remotely sensed scenes. To this end, this paper proposed a novel method called radiance extreme area compensation fusion (RECF). Based on the architecture of spectral unmixing fusion, our method uses the reconstruction of error map to construct local smoothing constraints during unmixing and utilizes the nearest-neighbor multispectral data to achieve optimal replacement compensation, thereby eliminating the impact of overexposed and underexposed areas in hyperspectral data on the fusion effect. We compared the RECF method with 11 previous published methods on three sets of airborne hyperspectral datasets and HJ2 satellite hyperspectral data and quantitatively evaluated them using 5 metrics, including PSNR and SAM. On the test dataset with extreme radiance interference, the proposed RECF method achieved well in the overall evaluation results; for instance, the PSNR metric reached 47.6076 and SAM reached 0.5964 on the Xiong'an dataset. In addition, the result shows that our method also achieved better visual effects on both simulation and real datasets.
  Accession Number: 1248
  ISSN:
  eISSN: 2072-4292
• Record 77 of
  
  Title:Modeling of 1.7 μm and 2.4 μm Dual-Wavelength Pumped 4.3 μm Dysprosium-Doped Chalcogenide Fiber Lasers
  
  Author(s):Xiao, Yang; Cui, Jian; Xiao, Xusheng; Xu, Yantao; Guo, Haitao
  Source: IEEE JOURNAL OF QUANTUM ELECTRONICS  Volume: 60  Issue: 2  DOI: 10.1109/JQE.2024.3350688  Published: 2024  
  Abstract:A novel 1.7 mu m and 2.4 mu m dual-wavelength pumping scheme for a 4.3 mu m dysprosium (Dy3+)-doped chalcogenide fiber laser was theoretically demonstrated. It was attributed to the 2.4 mu m excited stated absorption (ESA, H-6(13/2 -> )6 H(9/2 , )(6)F(11/2 )transition). Theoretically, when the two pumps were 5 W and 2 W, respectively, a laser power of 1.5 W with an remarkable efficiency of 30.2% was obtained from the home-made Dy3+:Ga0.8As34.2Sb5S60 glass fiber with a loss coefficient of 3 dB/m and a Dy3+ concentration of 3.67 x 10(25) ions/m3. Results indicated that the dual-wavelength pumping scheme based on the gain fiber provides a potential way to 4.3 mu m dysprosium-doped chalcogenide fiber lasers.
  Accession Number: 1600106
  ISSN: 0018-9197
  eISSN: 1558-1713
• Record 78 of
  
  Title:Inverse Calculation and Regularization Process for the Solar Aspect System (SAS) of HXI Payload on ASO-S Spacecraft
  
  Author(s):Yu, Ji-Rui; Ruan, Ping; Su, Yang; He, Ying-Hong; Tao, Jin-You; Zhang, Zhe; Guo, Song; Xue, Bin; Yang, Jian-Feng
  Source: RESEARCH IN ASTRONOMY AND ASTROPHYSICS  Volume: 24  Issue: 4  DOI: 10.1088/1674-4527/ad283b  Published: 2024  
  Abstract:For the ASO-S/HXI payload, the accuracy of the flare reconstruction is reliant on important factors such as the alignment of the dual grating and the precise measurement of observation orientation. To guarantee optimal functionality of the instrument throughout its life cycle, the Solar Aspect System (SAS) is imperative to ensure that measurements are accurate and reliable. This is achieved by capturing the target motion and utilizing a physical model-based inversion algorithm. However, the SAS optical system's inversion model is a typical ill-posed inverse problem due to its optical parameters, which results in small target sampling errors triggering unacceptable shifts in the solution. To enhance inversion accuracy and make it more robust against observation errors, we suggest dividing the inversion operation into two stages based on the SAS spot motion model. First, the as-rigid-as-possible (ARAP) transformation algorithm calculates the relative rotations and an intermediate variable between the substrates. Second, we solve an inversion linear equation for the relative translation of the substrates, the offset of the optical axes, and the observation orientation. To address the ill-posed challenge, the Tikhonov method grounded on the discrepancy criterion and the maximum a posteriori (MAP) method founded on the Bayesian framework are utilized. The simulation results exhibit that the ARAP method achieves a solution with a rotational error of roughly +/- 3.'' 5 (1/2-quantile); both regularization techniques are successful in enhancing the stability of the solution, the variance of error in the MAP method is even smaller-it achieves a translational error of approximately +/- 18 mu m (1/2-quantile) in comparison to the Tikhonov method's error of around +/- 24 mu m (1/2-quantile). Furthermore, the SAS practical application data indicates the method's usability in this study. Lastly, this paper discusses the intrinsic interconnections between the regularization methods. 35
  Accession Number: 45003
  ISSN: 1674-4527
  eISSN: 2397-6209
• Record 79 of
  
  Title:Analysis and simulation of the effect of large optical range difference of common path coherent-dispersion spectrometer on the detection of exoplanet radial velocities
  
  Author(s):Guan, Shouxin; Liu, Bin; Chen, Shasha; Wu, Yinhua; Wang, Feicheng; Wang, Shaofei; Liu, Xuebin; Wei, Ruyi
  Source: OPTICS COMMUNICATIONS  Volume: 561  Issue:   DOI: 10.1016/j.optcom.2024.130443  Published: 2024  
  Abstract:The Exoplanet Explorer common-path coherent-dispersion spectrometer (CODES) utilizes a unique combination of an asymmetric common path Sagnac interferometer and a low to medium resolution spectrometer. The ideal optical range difference (OPD) interval for CODES is OPD is an element of {15.06 mm, 19.45 mm}; however, the OPD of CODES is 64.3 mm to achieve better detection accuracy. Though they will increase the accuracy of detection, large OPDs outside of the ideal interval will also reduce the contrast of the interference fringes, making phase changes more hazy. This may also significantly affect the radial velocity inversion and reduce CODES's instrumental accuracy. This study creates an inverse tone mapping operator based on the photographic model and designs an inverse tone mapping algorithm called CODESCE. The outcomes of the experiments demonstrate that the tone mapping algorithm CODESCE in this work is appropriate for enhancing the contrast of interference fringe images with high OPD, and it can enhance the contrast of interference fringes by three orders of magnitude when OPD = 64.3 mm; the processed interference fringes are located in the range of interference fringe curves of the optimal OPD. By comparison with other current approaches, the suggested algorithm yields superior processing outcomes.
  Accession Number: 130443
  ISSN: 0030-4018
  eISSN: 1873-0310
• Record 80 of
  
  Title:High accuracy ranging for space debris with spaceborne single photon Lidar
  
  Author(s):Tian, Yuan; Hu, Xiaodong; Chen, Songmao; Zhao, Yixin; Zhang, Xuan; Wang, Dingjie; Xu, Weihao; Xie, Meilin; Hao, Wei; Su, Xiuqin
  Source: OPTICS EXPRESS  Volume: 32  Issue: 7  DOI: 10.1364/OE.519002  Published: 2024  
  Abstract:The increasing risk posed by space debris highlights the need for accurate localization techniques. Spaceborne single photon Lidar (SSPL) offers a promising solution, overcoming the limitations of traditional ground -based systems by providing expansive coverage and superior maneuverability without being hindered by weather, time, or geographic constraints. This study introduces a novel approach leveraging non -parametric Bayesian inference and the Dirichlet process mixture model (DPMM) to accurately determine the distance of space debris in low Earth orbit (LEO), where debris exhibits nonlinear, high dynamic motion characteristics. By integrating extended Kalman filtering (EKF) for range gating, our method captures the temporal distribution of reflected photons, employing Markov chain Monte Carlo (MCMC) for iterative solutions. Experimental outcomes demonstrate our method's superior accuracy over conventional statistical techniques, establishing a clear correlation between radial absolute velocity and ranging error, thus significantly enhancing monostatic space debris localization.
  Accession Number:
  ISSN: 1094-4087
  eISSN:
• Record 81 of
  
  Title:Enhancing the spatial resolution of time-of-flight based non-line-of-sight imaging via instrument response function deconvolution
  
  Author(s):Wang, Dingjie; Hao, Wei; Tian, Yuyuan; Xu, Weihao; Tian, Yuan; Cheng, Haihao; Chen, Songmao; Zhang, Ning; Zhu, Wenhua; Su, Xiuqin
  Source: OPTICS EXPRESS  Volume: 32  Issue: 7  DOI: 10.1364/OE.518767  Published: 2024  
  Abstract:Non-line-of-sight (NLOS) imaging retrieves the hidden scenes by utilizing the signals indirectly reflected by the relay wall. Benefiting from the picosecond-level timing accuracy, time-correlated single photon counting (TCSPC) based NLOS imaging can achieve theoretical spatial resolutions up to millimeter level. However, in practical applications, the total temporal resolution (also known as total time jitter, TTJ) of most current TCSPC systems exceeds hundreds of picoseconds due to the combined effects of multiple electronic devices, which restricts the underlying spatial resolution of NLOS imaging. In this paper, an instrument response function deconvolution (IRF-DC) method is proposed to overcome the constraints of a TCSPC system's TTJ on the spatial resolution of NLOS imaging. Specifically, we model the transient measurements as Poisson convolution process with the normalized IRF as convolution kernel, and solve the inverse problem with iterative deconvolution algorithm, which significantly improves the spatial resolution of NLOS imaging after reconstruction. Numerical simulations show that the IRF-DC facilitates light-cone transform and frequency-wavenumber migration solver to achieve successful reconstruction even when the system's TTJ reaches 1200 ps, which is equivalent to what was previously possible when TTJ was about 200 ps. In addition, the IRF-DC produces satisfactory reconstruction outcomes when the signal-to-noise ratio (SNR) is low. Furthermore, the effectiveness of the proposed method has also been experimentally verified. The proposed IRF-DC method is highly applicable and efficient, which may promote the development of high-resolution NLOS imaging.
  Accession Number:
  ISSN: 1094-4087
  eISSN:
• Record 82 of
  
  Title:Effect of atmospheric environment on the stability of secondary electron emission from magnesium oxide and alumina surfaces
  
  Author(s):Lian, Zhuoxi; Zhu, Xiangping; Wang, Dan; Meng, Xiangchen; He, Yongning
  Source: JOURNAL OF PHYSICS D-APPLIED PHYSICS  Volume: 57  Issue: 12  DOI: 10.1088/1361-6463/ad15c0  Published: 2024  
  Abstract:MgO and Al2O3 are two typical ceramics with high secondary electron yield (SEY) and are widely applied in electron multiplier devices as dynode coating. However, dynodes in multipliers are inevitably exposed to various environments, degenerating their SEY performance. To specify the influence of the atmospheric environment on SEY for MgO and Al2O3 ceramics, we conducted environmental stability experiments on MgO and Al2O3 nanofilms. By exposing the nanofilms fabricated by atomic layer deposition to air for certain durations, it was found that although the MgO film possessed high SEY, its SEY decreased significantly as the storage duration increased, specifically, its SEY peak value (delta m) decreased from 5.97 to 3.35 after 180 d. Whereas the SEY of the Al2O3 film changed very little with the storage duration extending, its delta m decreased from 4.01 to 3.70 after 180 d, indicating the Al2O3 film had good SEY environmental stability. To reveal the mechanism of SEY degradation, the modification analysis of surface composition was implemented. It was found that the surface of MgO film underwent degradation besides unavoidable contamination, generating Mg(OH)2 and MgCO3. Whereas, there is no chemical reaction occurred on the Al2O3 surface. Combining the advantages of high SEY of MgO and good environmental stability of Al2O3, several Al2O3/MgO double-layer nanofilms were prepared. The delta m value of 20 nm MgO nanofilms covered by 1 nm Al2O3, decreased from 4.90 to 4.56, with a reduction of only 6.94% after 180 d. The results showed that the Al2O3 film achieved effective protection of the MgO film. The SEY environmental stability of the double-layer structure was significantly improved, and the effect of thickness on SEY was theoretically interpreted. This work makes significant sense for understanding the influence of the environment on the SEY for MgO and Al2O3, which has potential applications in electron multipliers.
  Accession Number: 125302
  ISSN: 0022-3727
  eISSN: 1361-6463
• Record 83 of
  
  Title:Adaptive location method for film cooling holes based on the design intent of the turbine blade
  
  Author(s):Hou, Yaohua; Wang, Jing; Mei, Jiawei; Zhao, Hualong
  Source: INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY  Volume: 132  Issue: 3-4  DOI: 10.1007/s00170-024-13456-4  Published: 2024  
  Abstract:Due to the inevitable deviation of the casting process, the dimensional error of the turbine blade is introduced. As a result, the location datum of the film cooling holes is changed, which has an impact on the machining accuracy. The majority of pertinent studies concentrate on the rigid location approach for the entire blade, which results in a modest relative position error of the blade surface but still fails to give the exact position and axial direction of the film cooling holes of the deformed blade. In this paper, the entire deformation of the blade cross-section curve is divided into a number of deformation combinations of the mean line curve based on the construction method of the blade design intent. The exact location of the film cooling holes in the turbine blade with deviation is therefore efficiently solved by a flexible deformation of the blade that optimises the position and axial direction of the holes. The verification demonstrates that the novel method can significantly reduce both the contour deviation of the blade surface and the location issue of the film cooling holes. After machining experiments, the maximum position deviation of the holes is reduced by approximately 80% compared to the rigid location method of the entire blade, and the average value and standard deviation are also decreased by about 70%.
  Accession Number:
  ISSN: 0268-3768
  eISSN: 1433-3015
• Record 84 of
  
  Title:The role of eye movement signals in non-invasive brain-computer interface typing system
  
  Author(s):Liu, Xi; Hu, Bingliang; Si, Yang; Wang, Quan
  Source: MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING  Volume: 62  Issue: 7  DOI: 10.1007/s11517-024-03070-7  Published: 2024  
  Abstract:Brain-Computer Interfaces (BCIs) have shown great potential in providing communication and control for individuals with severe motor disabilities. However, traditional BCIs that rely on electroencephalography (EEG) signals suffer from low information transfer rates and high variability across users. Recently, eye movement signals have emerged as a promising alternative due to their high accuracy and robustness. Eye movement signals are the electrical or mechanical signals generated by the movements and behaviors of the eyes, serving to denote the diverse forms of eye movements, such as fixations, smooth pursuit, and other oculomotor activities like blinking. This article presents a review of recent studies on the development of BCI typing systems that incorporate eye movement signals. We first discuss the basic principles of BCI and the recent advancements in text entry. Then, we provide a comprehensive summary of the latest advancements in BCI typing systems that leverage eye movement signals. This includes an in-depth analysis of hybrid BCIs that are built upon the integration of electrooculography (EOG) and eye tracking technology, aiming to enhance the performance and functionality of the system. Moreover, we highlight the advantages and limitations of different approaches, as well as potential future directions. Overall, eye movement signals hold great potential for enhancing the usability and accessibility of BCI typing systems, and further research in this area could lead to more effective communication and control for individuals with motor disabilities.Graphical AbstractThis article delves into three pivotal components of the BCI typing system: data, algorithms, and interaction. The system leverages eye movement and EEG data as inputs, which are processed through algorithms for data fusion, feature extraction, and classification to yield output results. Furthermore, it facilitates real-time interaction by providing visual feedback via an efficient user interface.
  Accession Number:
  ISSN: 0140-0118
  eISSN: 1741-0444