摘要：采用白果浆为原料进行喷雾干燥工艺研究。以进气温度、风量、出气温度、进料质量分数为影响因素,设计了L16(45)的正交试验,对干燥白果粉末性能(含水量(MC)、色差(CD)、平均粒径(MPS)、蛋白质质量分数(wp))进行了分析。结果表明:出口气体温度对白果粉末的MC和wp有显著影响,进料质量分数对白果粉末的MPS有显著影响,进口气体对白果粉末的wp有一定影响。得出白果喷雾干燥制粉的最佳工艺条件为:进气温度190℃,风量120 m3/h,出气温度110℃,进料质量分数10%。在此条件下得到的粉末质量特性:含水量5.20%(质量分数),色差19.76,平均粒径22.0μm,wp 9.83%,均达到最佳质量范围。

摘要：CD8+T细胞主要通过T细胞表面受体(T cell recep tor,TCR)识别并与Ⅰ型主要组织性复合物提呈的抗原(pMHC-Ⅰ)相互作用[1]。TCR对刺激型抗原的识别在CD8+T细胞毒性和适应性免疫中发挥着关键作用。许多证据表明机械力可以延长TCR与刺激性pMHC作用的键合时间(bond lifetime)形成抗原特异性逆锁键(catch bond)[2],并且这种逆锁键对抗原识别非常重要。然而,机械力调控TCR抗原识别的具体结构机制仍不清楚。通过分子动力学模拟、单分子生物膜力学探针、磁镊、T细胞活化实验和动物模型对此问题展开了系统的研究[4]。发现作用在TCR-pMHC-Ⅰ复合体上的拉力可以作用在TCR-pMHC-Ⅰ复合体上的拉力可以打破MHC-I分子内部α1-α2和β2结构域间的相互作用,导致α1-α2结构域旋转并发生构象变化。力诱导的MHC-I构象变化可以进一步别构地调节TCR与刺激性抗原肽及α1-α2结构域的构象及相互作用,诱导产生新的氢键,增强TCR-pMHC-Ⅰ之间的键合时间,但并不能增强TCR与抑制性pMHC-Ⅰ之间的作用。当用点突变阻断这些新形成的氢键,或者α1-α2和β2结构域被二硫键锁住时,最佳力诱导的TCR-pMHC-Ⅰ作用的键合时间明显缩短并且T细胞的活化受到抑制。另外,在人TCR和HLA-A2相互作用中发现了类似机制,并且与肿瘤相关的HLA-A2点突变[3]可以通过限制HLA-A2α1--α2和β2结构域之间的构象打开减弱TCR对肿瘤抗原的识别及T细胞的功能。研究结果表明,机械力诱导的MHC-I构象变化对TCR抗原识别和T细胞活化非常重要,进一步地阐明了机械力调控TCR抗原识别机制,为临床肿瘤的免疫治疗和药物设计提供了新思路和新靶点。

摘要：The Giant Radio Array for Neutrino Detection(GRAND)is a planned large-scale observatory of ultra-high-energy(UHE)cosmic particles,with energies exceeding 10~8 Ge *** goal is to solve the long-standing mystery of the origin of UHE cosmic *** do this,GRAND will detect an unprecedented number of UHE cosmic rays and search for the undiscovered UHE neutrinos and gamma rays associated to them with unmatched *** will use large arrays of antennas to detect the radio emission coming from extensive air showers initiated by UHE particles in the *** design is modular:20 separate,independent sub-arrays,each of 10000 radio antennas deployed over 10000 km^2.A staged construction plan will validate key detection techniques while achieving important science goals *** we present the science goals,detection strategy,preliminary design,performance goals,and construction plans for GRAND.

摘要：The orchards usually have rough terrain,dense tree canopy and *** is hard to use GNSS for autonomous navigation in orchard due to signal occlusion,multipath effect,and radio frequency *** achieve autonomous navigation in orchard,a visual navigation method based on multiple images at different shooting angles is proposed in this paper.A dynamic image capturing device is designed for camera installation and multiple images can be shot at different ***,the obtained orchard images are classified into sky and soil detection *** image is transformed to HSV space and initially segmented into sky,canopy and soil regions by median filtering and morphological ***,the sky and soil regions are extracted by the maximum connected region algorithm,and the region edges are detected and filtered by the Canny ***,the navigation line in the current frame is extracted by fitting the region coordinate *** the dynamic weighted filtering algorithm is used to extract the navigation line for the soil and sky detection stage,respectively,and the navigation line for the sky detection stage is mirrored to the soil ***,the Kalman filter algorithm is used to fuse and extract the final navigation *** test results on 200 images show that the accuracy of visual navigation path fitting is 95.5%,and single frame image processing costs 60 ms,which meets the real-time and robustness requirements of *** visual navigation experiments in Camellia oleifera orchard show that when the driving speed is 0.6 m/s,the maximum tracking offset of visual navigation in weed-free and weedy environments is 0.14 m and 0.24 m,respectively,and the RMSE is 30 mm and 55 mm,respectively.