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Aiming at the complex environment inside the oil-immersed transformer, a spherical detection robot is proposed according to the design requirements such as a fault detection. Taking the pendulum eccentric torque as the core, two drive mechanism schemes are proposed. Based on the advantages of Simscape parametric modeling, the Simscape physical model is established, and then the influence of different pendulum lengths on the upward and downward fluctuation amplitude and forward speed of spherical robots is analyzed by changing the radial position of the heavy hammer. At the same time, according to the simulation comparison and the bearing capacity of the instrument inside the spherical robot, the appropriate drive mechanism scheme is selected. Then, the dynamic model of the drive mechanism is constructed, and the rationality of the eccentric moment drive mechanism of the single pendulum is analyzed and verified. Finally, according to the special requirements of the structure and environment of the oil-immersed transformer, physical experiments are carried out to verify the optimization effect of the drive mechanism. The results show that in the face of different task environments, the swing length can be changed according to the demand to control the fluctuation amplitude and forward speed of the spherical robot, so that the fluctuation amplitude and forward speed of the robot are within the tolerance range of the internal instrument, and the fault detection is better carried out in the narrow area of the oil-immersed transformer, which provides a basis for the development of the experimental prototype of the spherical detection robot of the oil-immersed transformer later.

A 3-RPS parallel leveling mechanism based on the proportional integral (PI) robust sliding mode system is designed to solve the problem of data acquisition inaccuracy caused by vehicle tilting during the robot walking. Firstly, the configuration synthesis is carried out according to the spiral and inverse spiral theory. Then, the dynamic analysis and calculation of the 3-RPS leveling mechanism are carried out to construct its dynamic model. On this basis, the adaptive robust sliding mode algorithm is introduced to optimize and improve the PI controller to improve the stability and adaptive correction ability. The stability of the nonlinear control system is verified by Lyapunov function. Finally, the control error curve is obtained by Matlab/Simulink comparative simulation experiment. The simulation results show that the adaptive correction effect of the PI control system optimized by the robust sliding mode algorithm is remarkable, and the steady-state error of the control is greatly reduced. The research provides a basis for the development of physical prototype of 3-RPS parallel leveling mechanism.

Meta-iodobenzylguanidine (MIBG) is used as a chemical precursor of radioiodinated (123I or 131I) MIBG preparation. In order to control the quality of MIBG, in this study, Infrared identification of self-made MIBG was carried out, the physical and chemical properties of solubility, pH, melting point and drying weight loss were determined, the content of elemental impurities was determined by ICP-MS, the headspace gas chromatography of residual solvent was established, and the content and related substances were determined by HPLC were established. The results for multiple batches of MIBG analysis showed that they met the requirements for medicinal precursors, the infrared spectrum of MIBG was consistent with that of the reference substance, the pH was in the range of 4.0-6.0, the melting point was 167-170 ℃, and the drying weight loss was less than 0.3%; ethanol residue was less than 0.5%, the content of elemental impurities was lower than the control threshold, together with no related impurities detected, and the contents of MIBG were 98.0%-102.0%. The quality standard of MIBG established in this study provides and provided basis for the quality control of MIBG.

In this work, MgO-coated carbon nanotubes (MgO@CNTs) were synthesized via the co-deposition technique. The samples of MgO@CNTs were treated by using the high power ultrasonic vibration with a long time to verify their structural stability. Microstructure of the CNTs and MgO@CNTs was characterized by using the FI-IT spectra analysis, scanning electron microscope and transmission electron microscope. The experiment result reveals that the high power ultrasonic vibration and the long-time ultrasonic-treatment can easily cut off the CNTs, while the MgO nanoparticles are still tightly adsorbed on the surface of CNTs without removing away from the surface of CNTs by the ultrasonic vibration. It means that MgO@CNTs is a novel reinforcement for the Mg-based composite because the MgO nanoparticles and CNTs have formed a good interface bonding with high stability. Simultaneously, the stable interfacial bonding between MgO and CNTs is explained by the first- principle calculation.

BackgroundCopper[64Cu] chloride solution is commonly used as raw material for the preparation of radiopharmaceuticals, which can be used in PET imaging or as a paired nuclide for tumor theranostic. Quality control test of copper[64Cu] chloride solution for radiolabelling must be done before use, and the radiochemical purity test is the key item of quality control.PurposeThis study aims to establish a rapid and reliable method for radiochemical purity analysis of copper[64Cu] chloride solution, by screening the test conditions of stationary phase and mobile phase.MethodsiTLC-SG silica gel paper plate was used as the stationary phase, and the mixed solution of dichloromethane, acetonitrile, methanol and 0.05 mol∙L-1 HCl was used as the mobile phase. The reference solution was prepared by mixing the test solution with DTPA solution in equal volume. The test solution and the reference solution were loaded on the paper plate separately and developed using the mobile phase. The kinds of stationary phase, composition and proportion of the mobile phase were optimized.ResultsUnder the optimized conditions, the Rf of the test solution is greater than 0.9 and the Rf of the reference solution is less than 0.1, and the separation degree is greater than 1.0, which satisfies the system suitability of thin-layer chromatography (TLC).ConclusionsEstablished method in this study is simple, reliable and rapid for the detection of radiochemical purity of copper[64Cu] chloride solution, and complying with the technical requirements of European pharmacopoeia for the determination of radionuclide solution for radiolabelling.

Coronavirus disease 2019 (COVID-19) is now a major public health problem worldwide. Infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is extremely strong. The one major target of the virus is the lung, which leads to the deaths of respiratory distress syndrome and multiple organ failure. The kidney is also one of the main organs attacked by viruses, which directly damage the renal tubules through angiotensin converting enzyme-2 and cause cytokine storm, resulting in kidney damage and increasing the risk of death in the patients. Early investigation of risk factors for kidney injury, detection of kidney injury indicators, timely supporting treatment and renal replacement therapy for the existence of kidney injury patients are useful for reducing the mortality rate of COVID-19 patients.