鱼体中的肠道微生物菌群是一道天然的免疫屏障, 能抑制病原微生物的定居和增殖, 从而使鱼体免受病害侵袭。洞庭湖是重要鱼类及水生生物的栖息地和基因库, 其中鲤形目(Cypriniformes)和鲈形目(Perciformes)种类最多, 鲇形目(Siluriformes)种类相对较少。洞庭湖鱼类群落结构及生物多样性已引起广泛关注, 但生态系统还是受到了一定程度的破坏, 很少有研究将其肠道微生物群的特征作为改善洞庭湖生态系统的潜在因素。为了探测洞庭湖重要鱼类中的微生物群, 使用16S rRNA高通量测序表征了鲇形目、鲈形目和鲤形目中6种鱼［黄颡鱼(Pelteobagrus fulvidraco)、鳜鱼(Siniperca chuatsi)、鲫鱼(Carassius auratus)、翘嘴鱼(Culter alburnus)、草鱼(Ctenopharyngodom idella)、鲢鱼(Hypophthalmichthys molitrix)］的肠道细菌群落多样性、组成和潜在的功能。所有鱼类肠道样本中有5种优势菌门, 包括厚壁菌门(Fimicutes)、变形杆菌门(Proteobacteria)、梭杆菌门(Fusobacteriota)、放线菌门(Actinobacteriota)和蓝细菌门(Cyanobacteria)。鲤形目和鲈形目鱼类的细菌组成相似, 鲇形目中醋酸杆菌属(Cetobacterium)所占比例高, 而鲤形目中醋酸杆菌属和气单胞菌属(Aeromonas)所占比例均高。对这6种鱼类肠道微生物群的微生物群落的物种组成和功能进行预测, 发现鳜鱼肠道微生物菌群物种的丰富度最高, 并且代谢过程较为旺盛, 推测这可能与鲈形目的抗病能力和适应能力有关。深入了解鱼类肠道微生物菌群的多样性、组成与潜在功能, 不仅可以更好地对微生态制剂使用和其水质管理进行调控, 而且对鱼类的健康养殖具有重要的参考价值。

为优化制造工艺和提高生产效率，针对航天固体火箭发动机壳体用30Cr3超高强度钢进行激光焊接特性研究。在焊接过程中通过对匙孔和熔池的高速摄影进行实时观察，发现在所选激光功率范围内存在三种不同的焊接熔透模式，包括匙孔未穿透型熔透模式、匙孔临界穿透型熔透模式和匙孔稳定穿透型熔透模式。采用激光测振仪对熔池表面的波动幅度进行了定量测量，并讨论了不同熔透模式下焊接过程的动态稳定性。基于熔透模式的划分，分析了匙孔动态行为与焊接接头组织和力学性能之间的关系。结果表明，在匙孔临界穿透型熔透模式下焊缝组织晶粒大小不均且接头塑、韧性较差。比较三种焊接熔透模式，发现匙孔稳定穿透型熔透模式有助于获得致密、均匀且杂质少的焊缝组织，焊接接头具备最高的断后伸长率（22.8%）和最大的冲击吸收功（14.36 J）。

针对红外图像的边缘细节特征不清晰、整体对比度低等问题，提出一种结合单参数同态滤波和限制对比度的自适应直方图均衡的红外图像增强算法。首先，基于单参数的同态滤波对图像进行处理，研究一种单一参数的传递函数，使得同态滤波算法参数可控且不依赖于实验经验，同时明显增强红外图像的细节特征。然后，利用限制对比度的自适应直方图均衡化对红外图像进行动态范围调整，提高红外图像对比度。实验仿真结果表明，该算法可以明显增强图像细节特征、提高图像对比度，使红外图像更有利于后续观察。

针对传统的悬臂梁振动抑制系统建立动力学方程的复杂性和精确性不高等缺点, 该文提出利用多物理场耦合仿真软件搭建悬臂梁系统作为被控对象, 通过设计比例、积分、微分(PID)算法在Simulink中建立控制器模型, 对悬臂结构进行振动控制联合仿真。由于结构具有未知性,因而传统控制器PID参数的选取常需根据经验进行试凑来确定。通过提出遗传算法优化PID参数的模型, 从而实现参数在线优化实时控制压电悬臂梁振动, 仿真和实验均验证了该模型的有效性。此外还通过改变压电执行器在悬臂梁不同应力处的位置进行了振动抑制的仿真与实验。结果表明, 该算法模型具有很好的鲁棒性, 在不同位置处均可获得最佳的PID整定参数, 实现振动抑制最佳效果。

This work demonstrates a smartphone-based automated fluorescence analysis system (SAFAS) for point-of-care testing (POCT) of Hg(II). This system consists of three modules. The smartphone module is used to provide an excitation light source, and to collect and analyze fluorescent images. The dark box module is applied to integrate the desired optical elements and offers a dark environment. The cost of the integrated dark box mainly includes the upper cover, box body, lower bottom, fixture and some optical elements which is about $109. The chip module is used for fluorescence sensing, which is composed of an upper plate, bottom plate and cloth-based chip. Due to the integration of multiple smartphone functions, the SAFAS eliminates the need for additional power sources, light sources and analysis systems. The dark box and upper and bottom plates are made by 3D printer. The cloth-based chip (about $0.005 for each chip) is fabricated using the wax screen-printing technique, with no need for expensive and complex fabrication equipments. To our knowledge, the cloth-based microfluidic fluorescence detection method combined with smartphone functions is first reported. By using optimal conditions, the designed system can realize the quantitative detection of Hg(II), which has a linear range of 0.001–100μgmL?1 and a detection limit of 0.5ngmL?1. Additionally, the SAFAS has been successfully applied for detecting Hg(II) in actual water samples, with recoveries of 100.1%–111%, RSDs of 3.88%–9.74%, and fast detection time of about 1 min. Obviously, the proposed SAFAS has the advantages of high sensitivity, wide dynamic range, acceptable reproducibility, good stability and low cost. Therefore, it is believed that the presented SAFAS has great potential to perform the POCT of Hg(II) in different water samples.This work demonstrates a smartphone-based automated fluorescence analysis system (SAFAS) for point-of-care testing (POCT) of Hg(II). This system consists of three modules. The smartphone module is used to provide an excitation light source, and to collect and analyze fluorescent images. The dark box module is applied to integrate the desired optical elements and offers a dark environment. The cost of the integrated dark box mainly includes the upper cover, box body, lower bottom, fixture and some optical elements which is about $109. The chip module is used for fluorescence sensing, which is composed of an upper plate, bottom plate and cloth-based chip. Due to the integration of multiple smartphone functions, the SAFAS eliminates the need for additional power sources, light sources and analysis systems. The dark box and upper and bottom plates are made by 3D printer. The cloth-based chip (about $0.005 for each chip) is fabricated using the wax screen-printing technique, with no need for expensive and complex fabrication equipments. To our knowledge, the cloth-based microfluidic fluorescence detection method combined with smartphone functions is first reported. By using optimal conditions, the designed system can realize the quantitative detection of Hg(II), which has a linear range of 0.001–100μgmL?1 and a detection limit of 0.5ngmL?1. Additionally, the SAFAS has been successfully applied for detecting Hg(II) in actual water samples, with recoveries of 100.1%–111%, RSDs of 3.88%–9.74%, and fast detection time of about 1 min. Obviously, the proposed SAFAS has the advantages of high sensitivity, wide dynamic range, acceptable reproducibility, good stability and low cost. Therefore, it is believed that the presented SAFAS has great potential to perform the POCT of Hg(II) in different water samples.

为了减小原子重力仪的体积来提高其实用性，基于电光相位调制器的拉曼光是一个很有吸引力的方案。但是会因此产生额外的激光边带，对绝对重力测量带来很大影响。为了保证绝对重力测量准确度，针对贡献最大的拉曼光多余边带效应，通过理论模型与调制实验相结合的方式，实现其对重力测量影响的优化与评估。实验结果证明了多余边带效应评估方法的准确性，并将其不确定度评估至20 μGal。