Tetradentate Cyclometalated Platinum(II) Complexes for Efficient and Stable Organic Light-Emitting Diodes

As one of the most important phosphorescent emitters, tetradentate cyclometalated platinum(II) complexes have attracted much attention in recent years, because of the high luminescent efficiency, emission spectra, and color tuned easily, especially for the development of high-efficient deep-blue and “pure” blue emitters and single-doped white organic light-emitting diodes (OLEDs). Also, some platinum(II)-based OLEDs exhibited superior operational stability, indicating their potentials in full-color display and solid-state lighting applications. In this chapter, we will introduce the recent advances of the tetradentate cyclometalated platinum(II) complexes, including pyrazole, N-heterocyclic carbene, imidazole and pyridine-based complexes, molecular design, photophysical properties, and some of their device performances

Observation of non-contact Casimir friction

Quantum mechanics predicts the occurrence of random electromagnetic field fluctuations, or virtual photons, in vacuum. The exchange of virtual photons between two bodies in relative motion could lead to non-contact quantum vacuum friction or Casimir friction. Despite its theoretical significance, the non-contact Casimir frictional force has not been observed and its theoretical predictions have varied widely. In this work, we report the first measurement of the non-contact Casimir frictional force between two moving bodies. By employing two mechanical oscillators with resonant frequencies far lower than those in Lorentz models of electrons in dielectric materials, we have amplified the Casimir frictional force at low relative velocities by several orders of magnitude. We directly measure the non-contact Casimir frictional force between the two oscillators and show its linear dependence on velocity, proving the dissipative nature of Casimir friction. This advancement marks a pivotal contribution to the field of dissipative quantum electrodynamics and enhances our understanding of friction at the nanoscale

A Spatiotemporal Reallocation Method for Energy Management in Edge Data Centres

Edge data centres (EDCs) have been widely developed in these years to supply delay-sensitive computing services, which impose prohibitive increasing electricity costs for EDC operators. This paper develops a new spatiotemporal reallocation (STR) method for energy management in EDCs. This method uses spare resources, including servers and energy storage systems (ESSs) within EDCs to reduce energy costs based on both spatial and temporal features of spare resources. This solution: 1) reallocates flexible workload between EDCs within one cluster; and 2) coordinates electricity load of data processing, ESSs and distributed energy resources (DERs) within one EDC cluster to gain benefits from flexible electricity tariffs. In addition, this paper the first time develops a Bit-Watt transformation to simplify the STR method and represent the relation between data workload and electricity consumption of EDCs. The case studies justified the developed STR method delivers satisfied costs reduction with robustness. The STR method fully utilized both spatial and temporal features of spare resources in EDCs to gain benefits from 1) the varying electricity tariffs, and 2) maximumly consuming the DER generation

A Spatiotemporal Reallocation Method for Energy Management in Edge Data Centres

Edge data centres (EDCs) have been widely developed in these years to supply delay-sensitive computing services, which impose prohibitive increasing electricity costs for EDC operators. This paper develops a new spatiotemporal reallocation (STR) method for energy management in EDCs. This method uses spare resources, including servers and energy storage systems (ESSs) within EDCs to reduce energy costs based on both spatial and temporal features of spare resources. This solution: 1) reallocates flexible workload between EDCs within one cluster; and 2) coordinates electricity load of data processing, ESSs and distributed energy resources (DERs) within one EDC cluster to gain benefits from flexible electricity tariffs. In addition, this paper the first time develops a Bit-Watt transformation to simplify the STR method and represent the relation between data workload and electricity consumption of EDCs. The case studies justified the developed STR method delivers satisfied costs reduction with robustness. The STR method fully utilized both spatial and temporal features of spare resources in EDCs to gain benefits from 1) the varying electricity tariffs, and 2) maximumly consuming the DER generation

Influence of crosswind on heller natural draft dry cooling tower and improvement measures

With the risk of water resources increasingly heavier and the need of the inland development of the nuclear power, dry cooling tower in power plant with its excellent water conservation characteristics, gets more and more attentions from the countries all over the world, especially in coal-rich but water-short areas. There are mainly three dry cooling tower forms: the air-cooled condenser(ACC), the natural draft dry cooling tower with surface type condenser(Harman system) and the natural draft dry cooling tower with jet condenser(Heller system).The radiator of Heller dry cooling tower is fixed up vertically all around the tower. Its heat transfer performance is greatly affected by environmental conditions, especially the crosswinds. The study of the effects of the crosswinds to the flow and heat transfer performance is essential to the design and optimization of the air cooling tower. Hence, the effects of the crosswinds to the flow and heat transfer performance of the air cooling system are investigated by a hot state model experimental platform. A new method adding air leading plates all around the tower to eliminate or ease the adverse effect of the crosswinds is put forward. The results show that the cooling tower flow field and temperature field are in symmetry without crosswinds. The flow and heat transfer performance of Heller air cooling system in different locations will encounter varying degrees of influence under crosswinds. The total air flow rate and the total heat transfer rate are also influenced. Under high crosswinds, airflow from windward side will oppress that from tower side and leeside. Flow a round circular cylinder is also formed. At this time, radial wind speed and effective into tower wind speed are small in tower side and leeside, heat transfer effect is poorer. The worst parts of flow and heat are mainly in the tower side. The influence mechanisms of environmental crosswinds and the certainty of heat transfer deterioration parts point out the direction for the further precautions. Adding air leading plates all around the tower is a very effective windproof measure which can improve the operating conditions greatly, change negative effect to positive effect.Papers presented at the 13th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Portoroz, Slovenia on 17-19 July 2017 .International centre for heat and mass transfer.American society of thermal and fluids engineers