Adaptive-Repetitive Visual-Servo Control of Low-Flying Aerial Robots via Uncalibrated High-Flying Cameras

This paper presents the design and implementation of an adaptive-repetitive visual-servo control system for a moving high-flying vehicle (HFV) with an uncalibrated camera to monitor, track, and precisely control the movements of a low-flying vehicle (LFV) or mobile ground robot. Applications of this control strategy include the use of high-flying unmanned aerial vehicles (UAVs) with computer vision for monitoring, controlling, and coordinating the movements of lower altitude agents in areas, for example, where GPS signals may be unreliable or nonexistent. When deployed, a remote operator of the HFV defines the desired trajectory for the LFV in the HFV’s camera frame. Due to the circular motion of the HFV, the resulting motion trajectory of the LFV in the image frame can be periodic in time, thus an adaptive-repetitive control system is exploited for regulation and/or trajectory tracking. The adaptive control law is able to handle uncertainties in the camera’s intrinsic and extrinsic parameters. The design and stability analysis of the closed-loop control system is presented, where Lyapunov stability is shown. Simulation and experimental results are presented to demonstrate the effectiveness of the method for controlling the movement of a low-flying quadcopter, demonstrating the capabilities of the visual-servo control system for localization (i.e.,, motion capturing) and trajectory tracking control. In fact, results show that the LFV can be commanded to hover in place as well as track a user-defined flower-shaped closed trajectory, while the HFV and camera system circulates above with constant angular velocity. On average, the proposed adaptive-repetitive visual-servo control system reduces the average RMS tracking error by over 77% in the image plane and over 71% in the world frame compared to using just the adaptive visual-servo control law.     

L3中心径迹室顶点位置分辨的改进

运用两种方法对L3中心任迹漂移室的顶点位置分辨进行了改进,一种是利用高能量分辨的电子和高动量分辨的μ子测量,限定轻子径迹的曲率半径,对径迹进行重新拟合;另一种是对中心径迹室每半边单元的径迹零位置位移进行校正.结合两种改进方法将轻子的顶点位置分辨由原来的137μm提高到60μm.     

Study on the mechanism of chiral recognition with molecularly imprinted polymers

This study aimed at elucidating the chiral recognition mechanism with molecularly imprinted polymers (MIPs) in aqueous environment. The system used ethylene glycol dimethacrylate (EGDMA), methacrylic acid (MAA), and 4-l-phenylalanylamino-pyridine (4-l-PheNHPy) as the cross-linking monomer, functional monomer and template, respectively, to assemble the imprinted polymer. A self-assembly mechanism, which includes the pre-organizing functional monomers around template before polymerization process, was proposed. This mechanism was supported by NMR titration test. Interactions between functional monomer and template were observed using UV-Vis spectroscopy of solutions of these components as well. These studies indicated a 1:2 molecular complex dominantly formed between 4-l-PheNHPy and MAA. Association constant was estimated to be 97,000 M⁻². Based on these results, a model mainly involving two-spot interaction was proposed evolving from our reported concept of exact placement of functional group. Ionic interaction between the primary amino group of 4-l-PheNHPy and carboxylic acid group inside the microcavity on MIPs was believed to play a predominate role in the enantioselectivity as supported by the observation of the relationship between the retention factor of 4-l-PheNHPy and the pH of mobile phase. While thermodynamic study at different pH revealed that, the interaction between the pyridyl group of 4-l-PheNHPy and the carboxylic acid group on the MIPs is also strong, implying that it also plays a profound role in determining the highly chiral selectivity of MIPs.     

8—取代香叶醇的简便合成方法

次氯酸可与二甲基取代的烯烃在二氯甲烷-水两相体系中反应生成烯丙基氯化物。这样的烯丙基氯化物既可进行官能团转化,又可进行碳—碳键形成反应。由次氯酸进行的烯氯化反应已用在某些天然物的合成中。     

傅里叶变换红外光声光谱在聚合物研究中应用——Ⅰ.苧麻结构

长期以来,纤维材料需要切成细微粉末才能测得红外光谱。1981年Teramae和Tana-ka采用傅里叶变换红外光声光谱(FTIR-PAS)获得棉花及尼龙纤维的红外光声光谱图,它与常规KBr制样得到的红外光谱图一致。该法不需要复杂制样,具有快速简便、无损样品的优点,所得的光谱图便于计算。其后,有人用此法研究了各种人造纤维和天然纤维性能     

大孔树脂脱除中药水煎液中铅、镉和铜的研究

为探讨D001、D113和D7513种大孔树脂对葛根、毛冬青、乌药和苦参4种中药水煎液中模拟超标的铅、铜和镉离子的脱除效果,将中药水提取液经浓硝酸消化后,采用原子吸收光谱法测定了中药水煎液经大孔树脂处理前后铅、铜和镉的质量浓度变化。结果表明,4种中药水煎液经3种大孔树脂处理后,铅、铜和镉含量都普遍降低。可认为D001、D113与D751都能够显著脱除4种中药水提取液中的铅、铜和镉,尤其对镉的脱除效果最好,对铜的脱除效果相对较差,但脱除率都在58.9%以上;大孔螯合树脂D751的脱除效果最好。     

Novel Poly(vinyl alcohol)/Chitosan/Modified Graphene Oxide Biocomposite for Wound Dressing Application

Rapid absorption of wound exudate and prevention of wound infection are prerequisites for wound dressing to accelerate wound healing. In this study, a novel kind of promising wound dressing is developed by incorporating polyhexamethylene guanidine (PHMG)‐modified graphene oxide (mGO) into the poly(vinyl alcohol)/chitosan (PVA/CS) matrix, conferring the dressing the required mechanical properties, higher water vapor transmission rate (WVTR), less swelling time, improved antibacterial activity, and more cell proliferation compared to the PVA/CS film crosslinked by genipin. In vivo experiments indicate that the PVA/CS/mGO composite film can accelerate wound healing via enhancement of the re‐epithelialization. PVA/CS/mGO composite film with 0.5 wt% mGO sheets displays the best wound healing properties, as manifested by the 50% higher antibacterial rate compared to GO and the wound healing rate of the mouse using this dressing is about 41% faster than the control group and 31% faster than the pure PVA/CS dressing. The underlying mechanism of the accelerated wound healing properties may be a result of the improved antibacterial ability to eradicate pathogenic bacteria on the wound area and maintain an appropriate moist aseptic wound healing environment to accelerate re‐epithelialization. These findings suggest that this novel composite PVA/CS/mGO film may have promising applications in wound dressing.     

NaCl对石灰石脱硫催化效果的理论分析

1引言NaCI对石灰石在流化床条件下脱硫的催化效果已有许多报导山。NaCI的作用表现在两方面：一是使锻烧生成的CaO具有较大的内孔尺寸，从而使CaO最终转换率提高；二是使反应速率加快。NaCI的这种功效被称催化为作用。对NaCI催化作用的基理解释，有各种假说，如生成CaO／NaCI共晶层，NaCI具有化学催化作用等，但这些假说都没有同时解释NaCI的两种催化效果。本文从气一固反应最关键的因素一吸收剂内孔结构着手来解释这种所谓‘催化”作用的原因所在。2多孔固体吸收剂内孔结构的渗透模型渗透模型是到目前为止对气体一多孔固体间反应…     

超高效液相色谱-三重四极杆质谱法同时测定美术颜料中33种游离态初级芳香胺

建立了超高效液相色谱-三重四极杆质谱法(UPLC-MS/MS)同时测定水粉画颜料、油画颜料、丙烯画颜料等美术颜料中33种初级芳香胺(PAAs)的检测方法。样品中的初级芳香胺用乙腈提取,经离心分离、氮吹浓缩后,以甲醇-水(1:9, v/v)定容至2 mL, 0.22 μm膜过滤后上机检测。采用BEH Phenyl柱(100 mm×2.1 mm, 1.7 μm),以含0.07%(v/v)甲酸的甲醇溶液-水(1:9, v/v)为流动相,梯度洗脱分离,UPLC-MS/MS多反应监测模式(MRM)检测,同位素内标法定量。方法优化了色谱分离条件、质谱碎裂电压、碰撞能量等,并考察了提取时间、提取溶剂、浓缩方式等对回收率的影响。33种初级芳香胺的方法检出限为5~50 μg/kg,定量限为15~150 μg/kg, 3种不同基质样品在3个添加水平的平均回收率为70.1%~115.8%,相对标准偏差(RSD)为2.1%~15%。本方法操作简便、快速、准确、灵敏度高,能满足相关测定的要求。