Gravity Wave Source Variations during the 2009 Stratospheric Sudden Warming

第2回極域科学シンポジウム/第35回極域宙空圏シンポジウム 11月15日（火） 国立極地研究所 2階大会議

Thermodynamic Modelling and Experimental Investigation of 3D Printed Inconel 718 Superalloy

In recent years, with the constant maturity of metal 3D printing technology, the additive manufacturing of IN718, nickel-base superalloy, has attracted very strong attention in the aerospace field. Additive manufacturing, especially the laser powder bed fusion (LPBF) of IN718, has several advantages over the conventionally manufactured IN718 (cast and wrought) because additive manufacturing is more time-saving with lower cost and a lower buy-to-fly ratio. However, 3D printed IN718 components still exhibit defects due to thermal gradient during printing. This thermal gradient affects the mechanical properties of printed parts to a large extent. Performing some special post-processing heat treatment could minimize this problem. However, only heat treatments designed for conventionally manufactured IN718 are currently applied to the printed material. Therefore, establishing and optimizing a thermodynamic database representing the 3D printed IN718 alloy is essential to effectively guide the heat treatment and obtain information on phase formation and transformation. In this work, firstly, a customized database was constructed by optimizing the phases presented in IN718, starting with the lower-order binary systems, followed by extrapolation to higher-order systems. The customized database is used to calculate the thermodynamic properties and predict phase formation in the IN718 alloy. Furthermore, to validate this database, experimental investigations, including differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), are done to determine the temperature of different phase transitions and the microstructure of the printed IN718 alloy. The modelling results obtained in the current work are more consistent with the current experimental results and the experimental results from the literature than the results obtained using two commercial databases

SOLUTION PROCESSABLE CARBON NANOTUBE DEVICES: FROM OPTOELECTRONICS TO BIOSENSING.

PhD ThesesSingle Walled Carbon nanotubes (SWCNTs) have attracted substantial attention due to their unique properties, such as one-dimensional architecture, excellent electrical properties, chemical stability for different modification and the easy integration into electronic circuits, which allows for the potential applications in field effect transistors, biosensors and optoelectronics. Despite these considerable achievements, it is still challenging to fabricate SWCNTs devices with low-cost processability and multipurpose capability. Herein, we propose facile, low cost, and solution processable strategies for the fabrication of SWCNT devices, which broaden the application of SWCNTs in different fields. In this work, DNA-wrapped SWCNTs were functionalised with specific and distinct aptamer sequences which were used as selective receptors to bio-analytes. These distinct SWCNT-aptamer hybrids were immobilised onto pre-patterned electrodes via dielectrophoresis (DEP) on the same chip into device configurations, forming multiplexed sensing devices. Multiplexed detection of three different analytes was successfully performed and real time detection was achieved in serum. Moreover, we reported the fabrication of protein-based biosensors, where the -lactamase binding proteins (BLIP2) were engineered with phenylazide handles at defined sites, which allowed us to control the orientations of BLIP attached to SWCNTs. Therefore, we can control the local electrostatic surface presented within the Debye length when TEM -lactamase was binding to BLIP2, thus modulating the conductance gating effect. The devices gave distinct responses depending on TEM presenting either negative or positive local charge patches. This indicates that local electrostatic properties act as the key driving force for electrostatic gating. iv Due to their nanoscale one dimensional (1D) architecture, we used SWCNTs as vector templates to fabricate devices with multiplexed metal wires. Since metal precursors were encapsulated inside the SWCNT templates, we were able to precisely control their size, shape and orientation via DEP. Multiscale characterization of the different fabrication steps revealed details of the structure and charge transfer between the material encapsulated and the carbon nanotube. Electrical measurements further demonstrated the successful fabrication of metal nanowire devices. Finally, we performed the separation of single chirality SWCNTs. By immobilised the separated (6,5), (7,5) and metallic tubes on the same chip, we demonstrated the fabrication of multiplexed single chirality SWCNT devices. Additionally, mixed chirality and single chirality SWCNTs were used to synthesize CdS-SWCNT hybrids for photodetection. The results showed that single chirality devices were more sensitive to green laser. Overall, we immobilised SWCNTs to fabricate nanoscale devices via a solution processable method. This makes the fabrication of devices processing multipurpose capability and easy processing possible, which is of importance for broadening the application of SWCNTs. We also demonstrated the applications of SWCNTs in electronics and biosensors. I hope our work can inspire others to develop SWCNT devices from theoretical research to practical applications

A Micropulse eye-safe all-fiber molecular backscatter coherent temperature lidar

In this paper, we analyze the performance of an all-fiber, micropulse, 1.5 μm coherent lidar for remote sensing of atmospheric temperature. The proposed system benefits from the recent advances in optics/electronics technology, especially an all-fiber image-reject homodyne receiver, where a high resolution spectrum in the baseband can be acquired. Due to the presence of a structured spectra resulting from the spontaneous Rayleigh-Brillouine scattering, associated with the relevant operating regimes, an accurate estimation of the temperature can be carried out. One of the main advantages of this system is the removal of the contaminating Mie backscatter signal by electronic filters at the baseband (before signal conditioning and amplification). The paper presents the basic concepts as well as a Monte-Carlo system simulation as the proof of concept

Lidar Observations of Elevated Temperatures in Bright Chemiluminescent Meteor Trails During the 1998 Leonid Shower

Seven persistent trails associated with bright fireballs were probed with a steerable Na wind/temperature lidar at Starfire Optical Range, NM during the 17/18 Nov peak of the 1998 Leonid meteor shower. These chemiluminescence trails were especially rich in Na. The average Na abundance within the trails was 52% of the background Na layer abundance, which suggests that the corresponding masses of the meteors were from 1 g up to 1 kg. CCD images show that the chemiluminescent emissions (including Na and OH) are confined to the walls of a tube, which expands with time by molecular diffusion. Lidar profiles within the trails show that the temperatures are highest at the edges of the tube where the airglow emissions are brightest. Approximately 3 min after ablation, temperatures at the tube walls are 20-50 K warmer than the tube core and background atmosphere. Neither chemical nor frictional heating provides a satisfactory explanation for the observations

Observations of Persistent Leonid Meteor Trails. 1. Advection of the Diamond Ring

From a single image of a persistent trail left by a -1.5 magnitude Leonid meteor on November 17, 1998, the relative winds between 92.5 and 98 km altitude are derived, where the altitudes are determined by a sodium lidar. These are converted to true winds 82 sec after the appearance of the meteor by fixing the winds at 98 km to match the results of following the trail with the lidar for twelve minutes. The image and winds reveal a fine example of the effects of a gravity wave having a vertical wavelenth of 5.50 ± 0.02 km, a horizontal wavelength of 2650 ± 60 kin, an intrinsic period of 19.5 ± 0.4 hours, and an observed period of 8.6 ± 0.1 hours. Effects of the gravity wave are still present in the wind field 70 rain later

Lidar observations of polar mesospheric clouds at South Pole: Seasonal variations

Polar mesospheric clouds (PMCs) were observed above the geographic South Pole by an Fe Boltzmann temperature lidar from 11 Dec 99 to 24 Feb 00. During this 76-day period 297 h of observations were made on 33 different days and PMCs were detected 66.5% of the time. The mean PMC peak backscatter ratio, peak volume backscatter coefficient, total backscatter coefficient, layer centroid altitude, and layer rms width are 50.59 q- 2.33, 2.70 q- 0.12x10 -9 m-•sr -•, 3.61 q- 0.22x10 -6 sr -•, 85.49 q- 0.09 km, and 0.71 q- 0.03 km, respectively. The PMCs are highest near summer solstice when upwelling over the pole is strongest. The altitudes are 2-4 km higher than that typically observed elsewhere, including the North Pole. After solstice the mean altitudes decreases by about 64 m/day as the upwelling weakens.Ope

Lidar Studies of Interannual, Seasonal, and Diurnal Variations of Polar Mesospheric Clouds at the South Pole

Polar mesospheric clouds (PMC) were observed by an Fe Boltzmann temperature lidar at the South Pole in the 1999–2000 and 2000–2001 austral summer seasons. We report the study of interannual, seasonal, and diurnal variations of PMC using more than 430 h of PMC data. The most significant differences between the two seasons are that in the 2000– 2001 season, the PMC mean total backscatter coefficient is 82% larger and the mean centroid altitude is 0.83 km lower than PMC in the 1999–2000 season. Clear seasonal trends in PMC altitudes were observed at the South Pole where maximum altitudes occurred around 10–20 days after summer solstice. Seasonal variations of PMC backscatter coefficient and occurrence probability show maxima around 25–40 days after summer solstice. Strong diurnal and semidiurnal variations in PMC backscatter coefficient and centroid altitude were observed at the South Pole with both in-phase and out-of-phase correlations during different years. A significant hemispheric difference in PMC altitudes was found, that the mean PMC altitude of 85.03 km at the South Pole is about 2–3 km higher than PMC in the northern hemisphere. Through comparisons with the NCAR Thermosphere-Ionosphere-Mesosphere-Electrodynamics General Circulation Model (TIME-GCM), the hemispheric difference in PMC altitude is attributed to the hemispheric differences in the altitudes of supersaturation region and in the upwelling vertical wind, which are mainly caused by different solar forcing in two hemispheres that the solar flux in January is 6% greater than the solar flux in July due to the Earth’s orbital eccentricity. Gravity wave forcing also contributes to these differences.Ope

Unstructured road extraction and roadside fruit recognition in grape orchards based on a synchronous detection algorithm

Accurate road extraction and recognition of roadside fruit in complex orchard environments are essential prerequisites for robotic fruit picking and walking behavioral decisions. In this study, a novel algorithm was proposed for unstructured road extraction and roadside fruit synchronous recognition, with wine grapes and nonstructural orchards as research objects. Initially, a preprocessing method tailored to field orchards was proposed to reduce the interference of adverse factors in the operating environment. The preprocessing method contained 4 parts: interception of regions of interest, bilateral filter, logarithmic space transformation and image enhancement based on the MSRCR algorithm. Subsequently, the analysis of the enhanced image enabled the optimization of the gray factor, and a road region extraction method based on dual-space fusion was proposed by color channel enhancement and gray factor optimization. Furthermore, the YOLO model suitable for grape cluster recognition in the wild environment was selected, and its parameters were optimized to enhance the recognition performance of the model for randomly distributed grapes. Finally, a fusion recognition framework was innovatively established, wherein the road extraction result was taken as input, and the optimized parameter YOLO model was utilized to identify roadside fruits, thus realizing synchronous road extraction and roadside fruit detection. Experimental results demonstrated that the proposed method based on the pretreatment could reduce the impact of interfering factors in complex orchard environments and enhance the quality of road extraction. Using the optimized YOLOv7 model, the precision, recall, mAP, and F1-score for roadside fruit cluster detection were 88.9%, 89.7%, 93.4%, and 89.3%, respectively, all of which were higher than those of the YOLOv5 model and were more suitable for roadside grape recognition. Compared to the identification results obtained by the grape detection algorithm alone, the proposed synchronous algorithm increased the number of fruit identifications by 23.84% and the detection speed by 14.33%. This research enhanced the perception ability of robots and provided a solid support for behavioral decision systems