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CdS quantum dots (QDs) have been synthesized on a large scale, based on the direct thermolysis of one single-source precursor, (Me(4)N)(4)[S(4)Cd(10)(SPh)(16)], in hexadecylamine (HDA). Transmission electron microscopy (TEM) observations show that the CdS QDs are well-defined, nearly spherical particles. The clear lattice fringes in high-resolution TEM (HRTEM) images confirm the crystalline nature of the QDs. The broad diffraction in the x-ray diffraction (XRD) pattern and diffuse diffraction rings of the selected-area electron diffraction (SAED) pattern are typical of nanomeric-size particles and indicative of the hexagonal phase of CdS QDs. The absorption spectra confirm quantum confinement of CdS QDs. The synthesis process for CdS QDs was investigated by ultraviolet-visible (UV-vis) absorption spectroscopy. The results demonstrate that the nucleation and growth stages were separated automatically in a homogeneous system.

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Abstract. Current robotic prototypes mainly harvest fruit clusters by gripping and cutting the main rachis. However, severe cluster vibration and fruit falling may occur during speedy harvesting. Determining the characteristics of this vibration and falling is important to achieve optimal control in robotic harvesting. Therefore, a virtual grip-and-cut model of cluster picking was developed, and corresponding cluster vibration and fruit falling simulations were performed for robotic harvesting. Multi-property finite element modeling of the main rachis was based on measurements of the rachis compression, shearing, and bending properties. A simulation model of cluster vibration was then built and combined with an end-effector model to obtain a virtual model of grip-and-cut cluster picking. The 3D vibration simulation model of a fruit cluster coupled with the grip-and-cut end-effector model effectively characterized the complex vibration in multilevel and multicomponent fruit clusters with individual diversity of the components’ properties. With the virtual model for cluster picking, dynamic interactive simulation can be realized of the fruit cluster and the grip-and-cut end-effector. Experiments verified that the average deviation of the average swing angle and fruit falling ratio were 6.09% and 8.71%, respectively. Furthermore, the finger-rachis deviation and grip-and-cut speed had a significant influence on the swing angle and fruit falling ratio. The 3D vibration simulation model of a fruit cluster and the virtual model of cluster picking are useful tools for virtual analysis and design of robotic harvesters. Keywords: Falling, Fruit cluster, Harvesting, Robot, Simulation, Vibration.

Based on the theory of paradox cognition, a relationship model among paradox cognition, industrial green production, and enterprise performance has been constructed, which mainly focuses on a study on whether the paradox cognition can have positive influences on the green production behavior of industrial enterprises, and then further promote the improvement of enterprises' economic benefits. The author wrote this thesis on the basis of results obtained from 305 sample surveys and verified the direct and indirect influence relationships among variables in the model with structural equation path coefficient and mediation effect. The empirical results show that: firstly, paradox cognition has a positive and significant impact on the industrial green production behavior. The higher the level of paradox cognition, the more likely the enterprises are to implement the industrial green production behavior. Secondly, paradox cognition can improve the potential performance of enterprises by affecting "green product provision", "green production management", and "green production technology", and then indirectly improve the financial performance of enterprises.