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A passive residual heat removal heat exchanger (PRHR HX) was used as the research object, and an experimental device with heat conduction oil as the heat source was set up to complete the experimental study of the outside tube saturation boiling. The improved Wilson diagram method was used to calculate the experimental data, and the heat transfer law of the outside tube boiling of smooth tube and finned tube was obtained. Compared with the two types of tubes, the intensification rate of smooth tube was 1.07, and that of finned tube was 2.39, and the finned tube was 2.23 times that of smooth tube. According to the intensification rate, the Nu modification of the heat transfer coefficient of the two tubes was further obtained.

This study discussed the development and evolution of Chinese royal gardens from the initial generation period (Zhou, Qin and Han dynasties) to the late mature period (middle Qing Dynasty to the late Qing Dynasty). Through the specific analysis of the typical royal gardens in different periods, the development and changes of the gardening skills and overall layout of the royal gardens in each period were obtained, and the development characteristics of the whole historical period of the Chinese royal gardens were summarized. [ABSTRACT FROM AUTHOR]

Two C–C bridged Ni(II) complexes bearing β‐keto‐9‐fluorenyliminato ligands with electron‐withdrawing groups (─CF3), Ni{PhC(O)CHC[N(9‐fluorenyl)]CF2}2 (Ni1) and Ni{CF3C(O)CHC[N(9‐fluorenyl)]Ph}2 (Ni2), were synthesized by metal coordination reaction and different in situ bonding mechanisms. The C–C bridged bonds of Ni1 were formed by in situ intramolecular trifluoromethyl and 9‐fluorenyl carbon–carbon cross‐coupling reaction and those of Ni2 were formed by in situ intramolecular 9‐fluorenyl carbon–carbon radical coupling reaction mechanism. The obtained complexes were characterized using 1H NMR spectroscopy and elemental analyses. The crystal and molecular structures of Ni1 and Ni2 with C–C bridged configuration were determined using X‐ray diffraction. Ni1 and Ni2 were used as catalysts for norbornene (NB) polymerization after activation with B(C6F5)3 and the catalytic activities reached 106 gpolymer molNi−1 h−1. The copolymerization of NB and styrene catalyzed by the Ni1/B(C6F5)3 system showed high activity (105 gpolymer molNi−1 h−1) and the catalytic activities decreased with increasing feed content of styrene. All vinyl‐type copolymers exhibited high molecular weight (104 g mol−1), narrow molecular weight distribution (Mw/Mn = 1.71–2.80), high styrene insertion ratios (11.13–50.81%) and high thermal stability (Td > 380°C) and could be made into thin films with high transparency in the visible region (400–800 nm). Novel C–C bridged Ni(II) complexes bearing β‐keto‐9‐fluorenyliminato ligands with electron‐withdrawing groups were synthesized by metal coordination and different in situ intramolecular bonding mechanisms, and applied in the (co)polymerization of norbornene and styrene. The copolymers were obtained with high styrene monomer content, and exhibited high thermal stability, narrow molecular weight distribution and high transparency in the visible region. [ABSTRACT FROM AUTHOR]