Application performances of two greenhouses with new types of backwall in Yangling,China

In order to investigate the application performances of the solar greenhouses with new types of backwall(greenhouse W_(2),and greenhouse W_(3))and the ordinary clay brick backwall greenhouse(greenhouse W_(1)),and provide a theoretical basis for the construction of solar greenhouse in Yangling Demonstration Zone,Shaanxi,China,two greenhouses with different new types of backwall were designed.The backwall of one of them was built with lightweight aggregate concrete block(greenhouse W_(2))and that of the other one was assembled with a row of sand-filled cement pipes(greenhouse W_(3)).The tested greenhouses were constructed in Yangling Demonstration Zone.Based on the data collected on typical sunny and cloudy days,the indoor temperature,inside wall temperature,and the heat flow of the greenhouses with new types of backwall were compared with those detected in the ordinary clay brick backwall solar greenhouse,and the tested results were numerically simulated.According to the comparison of the physiological indicators of tomatoes planted in the greenhouses and the construction costs,the greenhouse type with the best practicability was found.The results indicated that:The average air temperature in greenhouses W_(1),W_(2),and W_(3)and outside was 15.1℃,15.9℃,17.3℃,and−0.4℃ on the night of a sunny day,and the air temperature in W_(3)was the highest.The average air temperature in greenhouses W_(1),W_(2),and W_(3)and outside were 9.5℃,13.3℃,11.0℃,and−5.5℃ on the night of a cloudy day,the air temperature in W_(2)was the highest.In the depth of 0-330 mm from the interface of the backwalls,the walls were obviously affected by the solar radiation,and the temperature changed greatly.The wall temperature on the sunny days exhibited an ascending order of W_(1),W_(2),W_(3),while on the cloudy days was in the ascending order of W_(1),W_(3),W_(2).The wall of W_(3)absorbed the most heat during the daytime and released the most heat at night on the sunny day,while W_(2)exhibited the second most heat absorption during the daytime,however,it exhibited the highest heat release at night on the cloudy day,which were almost equaled to its heat absorption.Tomatoes in W_(3)grew well and exhibited the highest yield,and this greenhouse had the lowest construction costs.Comprehensively considering the physiological indicators of tomatoes and the corresponding construction costs of greenhouses,W_(3)has the best application performance in Yangling Demonstration Zone.

Conductive hydrogels incorporating carbon nanoparticles:A review of synthesis,performance and applications

As one of the most rapidly expanding materials,hydrogels have gained increasing attention in a variety of fields due to their biocompatibility,degradability and hydrophilic properties,as well as their remarkable adhesion and stretchability to adapt to different surfaces.Hydrogels combined with carbon-based materials possess enhanced properties and new functionalities,in particular,conductive hydrogels have become a new area of research in the field of materials science.This review aims to provide a comprehensive overview and up-to-date examination of recent developments in the synthesis,properties and applications of conductive hydrogels incorporating several typical carbon nanoparticles such as carbon nanotubes,graphene,carbon dots and carbon nanofibers.We summarize key techniques and mechanisms for synthesizing various composite hydrogels with exceptional properties,and represented applications such as wearable sensors,temperature sensors,supercapacitors and human-computer interaction reported recently.The mechanical,electrical and sensing properties of carbon nanoparticles conductive hydrogels are thoroughly analyzed to disclose the role of carbon nanoparticles in these hydrogels and key factors in the microstructure.Finally,future development of conductive hydrogels based on carbon nanoparticles is discussed including the challenges and possible solutions in terms of microstructure optimization,mechanical and other properties,and promising applications in wearable electronics and multifunctional materials.

Graphene/phosphorene nano-heterojunction:facile synthesis, nonlinear optics, and ultrafast photonics applications with enhanced performance

Owing to its thickness-modulated direct energy band gap, relatively strong light–matter interaction, and unique nonlinear optical response at a long wavelength, few-layer black phosphorus, or phosphorene, becomes very attractive in ultrafast photonics applications. Herein, we synthesized a graphene/phosphorene nano-heterojunction using a liquid phase-stripping method. Tiny lattice distortions in graphene and phosphorene suggest the formation of a nano-heterojunction between graphene and phosphorene nanosheets. In addition, we systematically investigate their nonlinear optical responses at different wavelength regimes. Our experiments indicate that the combined advantages of ultrafast relaxation, broadband response in graphene, and the strong light–matter interaction in phosphorene can be combined together by nano-heterojunction. We have further fabricated two-dimensional(2D) nano-heterojunction based optical saturable absorbers and integrated them into an erbium-doped fiber laser to demonstrate the generation of a stable ultrashort pulse down to 148 fs. Our results indicate that a graphene/phosphorene nano-heterojunction can operate as a promising saturable absorber for ultrafast laser systems with ultrahigh pulse energy and ultranarrow pulse duration. We believe this work opens up a new approach to designing 2D heterointerfaces for applications in ultrafast photonics and other research.The fabrication of a 2D nano-heterojunction assembled from stacking different 2D materials, via this facile and scalable growth approach, paves the way for the formation and tuning of new 2D materials with desirable photonic properties and applications.

A Practical Approach to Representation of Real-time Building Control Applications in Simulation

Computer based automation and control systems are becoming increasingly important in smart sustainable buildings,often referred to as automated buildings(ABs),in order to automatically control,optimize and supervise a wide range of building performance applications over a network while minimizing energy consumption and associated green house gas emission.This technology generally refers to building automation and control systems(BACS)architecture.Instead of costly and time-consuming experiments,this paper focuses on development and design of a distributed dynamic simulation environment with the capability to represent BACS architecture in simulation by run-time coupling two or more different software tools over a network.This involves using distributed dynamic simulations as means to analyze the performance and enhance networked real-time control systems in ABs and improve the functions of real BACS technology.The application and capability of this new dynamic simulation environment are demonstrated by an experimental design,in this paper.

Container Cluster Scheduling Strategy Based on Delay Decision Under Multidimensional Constraints

With the rise of online applications such as machine learning,stream processing,and interactive data-intensive applications in shared clusters,container cluster scheduling in data centers is facing new challenges.In order to solve the problem that application performance and economic cost cannot be balanced in a container cluster deploying a hybrid application,this paper proposes a container cluster scheduling strategy based on delay decision under multi-dimensional constraints.Formal language-based application placement constraints were introduced,and a task reorder model was established based on delayed decision-making.The experiments show that this strategy improves application performance and cluster utilization.