The endless molecular topology endows cyclic polymers with fascinating physical properties and applications. As a powerful strategy for the preparation of well-defined cyclic polymers, the current ...ring-closure methods have an inherent disadvantage of low production efficiency under the classic batch reaction conditions due to the requirement of ultralow reaction concentration for ring-closing linear polymer precursors. Assisted by the continuous-flow technique, we developed an efficient and practical way to ingeniously solve this essential problem and successfully produce cyclic polymers on a large scale by a light-induced ring-closure method for the first time. In addition, due to the large surface-to-volume ratio of the flow reactor, the continuous-flow technique provides the light-induced ring-closing reaction with more uniform light irradiation and transmission, resulting in a significantly increased reaction efficiency compared to that from the classic batch reaction conditions.
Scalable preparation of cyclic polymers by the ring-closure strategy was achieved for the first time by virtue of the combination of a light-induced ring-closure method and the continuous-flow technique.
基于偏振特性的海洋溢油油种识别研究 LI Yingchao, 李英超; LIU Jianan, 刘嘉楠; SHI Haodong, 史浩东
Guang zi xue bao = Acta photonica sinica,
2021, Letnik:
50, Številka:
7
Journal Article
In this paper, an AC-DC multi-port traction power supply system with power electronic transformer is put forward. Based on this structure, the system control method is proposed to realize energy ...optimization and system stabilization. The system control method is proposed to divide the system state and utilize DC bus voltage information, aiming at achieving optimal energy utilization and system stability. The system consists of PV (photovoltaic) source DC system, wind energy communication system, energy storage module, regenerative braking module, DC micro-grid power supply module and local load, which can run in grid or island mode. The system is divided into five working modes, which are the main control DC bus voltage of PV source DC system under balanced state, the main control of island operation energy storage module, the main control of regenerative braking module, and the main control and communication of regenerative braking module in grid mode. The control methods of the PV interface converter, the grid side interface converter and the energy storage interface converter are respectively given. The simulation and the test results proof the usefulness of the proposed method.
The core technique of unmanned vehicle systems is the autonomous maneuvering decision, which not only determines the applications of unmanned vehicles but also is the critical technique many ...countries are competing to develop. Reinforcement Learning (RL) is the potential design method for autonomous maneuvering decision-making systems. Nevertheless, in the face of complex decision-making tasks, it is still challenging to master the optimal policy due to the low learning efficiency caused by the complex environment, high dimensional state, and sparse reward. Inspired by the human learning process from simple to complex, we propose a novel progressive deep RL algorithm for policy optimization in unmanned autonomous decision-making systems in this paper. The proposed algorithm divides the training of the autonomous maneuvering decision into a sequence of curricula with learning tasks from simple to complex. Finally, through the self-play stage, the iterative optimization of the policy is realized. Furthermore, the confrontation environment with two unmanned vehicles with obstacles is analyzed and modeled. Finally, the simulation leads to the one-to-one adversarial tasks demonstrate the effectiveness and applicability of the proposed design algorithm.
Effect of solution rate on electrospinning Ying Yang; Zhidong Jia; Jianan Liu ...
2007 Annual Report - Conference on Electrical Insulation and Dielectric Phenomena,
2007-Oct.
Conference Proceeding
The electrostatic force from the electric field and the Coulomb force between charges are key forces to overcome the surface tension and viscoelastic force. In this paper, we report the results of a ...systematic investigation of the effect of variation of the solution rate on the electrospinning of poly (ethylene oxide) water solution. The effect of solution rate on E range on the nozzle, the effect of solution rate on jet path, the effect of solution rate on limited fiber diameter were discussed. In our experiments, the smallest mean fiber diameter was produced at 1 ml/h, 40 cm and 35 kV. It was found that the limited fiber diameter was not decided by solution rate but decided by the electric force per unit mass and volatilization.
Avian researchers and the poultry industry have experienced a massive loss of genetic resources due to the high cost of maintaining live flocks. Cryobanking of germplasm is economical and ensures ...long-term availability of genetic resources. Cryopreservation and transplantation of avian gonadal tissue allow effective preservation and recovery of female germplasm and provide an alternative to semen cryobanking. A vitrification protocol including dimethyl sulphoxide, ethylene glycol and sucrose as cryoprotective agents and the use of acupuncture needles to facilitate tissue handling has been successful in preserving Japanese quail ovarian tissue. Its effectiveness in preserving testicular tissue is unknown and an efficient storage system is needed.
The vitrification protocol was first adapted to a 0.5-ml straw system and used to cryopreserve quail ovarian tissue, which showed no significant impairment of viability or vascularization compared to fresh tissue after in ovo culture. This system was then replaced by a simpler 2-ml straw system and applied to quail testicular and ovarian tissue. Normal morphology of testicular tissue was observed after in ovo culture and live offspring were produced by intramagnal insemination of the extrusion retrieved from allotransplants of cryopreserved testicular tissue. Donor-derived offspring were also efficiently produced from cryopreserved and allotransplanted ovarian tissue.
Gonadal transplantation is critical to functional recovery of cryopreserved tissue but can be limited by tissue rejection. Donor thymic tissue was implanted into recipient embryos and gonadal tissue from the same donor was transplanted ectopically to the recipient after hatching. Transplant viability and histology was examined. Thymic implantation may improve survival of the allogeneic gonadal transplants in chickens but not the xenotransplants from quail to chickens. Investigations of avian ovarian transplantation have led to intriguing additional observations. Donor-derived offspring were produced from transplanted adult quail ovarian tissue, although delayed age at first egg and reduced reproductive longevity were observed with the transplants. As well, offspring with chimeric plumage coloration were produced from cryopreserved and transplanted chicken ovarian tissue, indicating chimeric folliculogenesis.
This dissertation provides a model of cryobanking avian gonadal tissue using a simple vitrification method, and suggests future directions in improving transplantation tolerance and using gonadal transplantation in avian research.
