Study of High-Performance Chloroprene Sponge in Diving Suit Application
A diving-suit-used foam neoprene with high performance has been developed and its aging behaviors in QUV accelerated aging tank and temperature cyclic chamber were investigated. The results show that the tensile strength and tear strength of the material are decreased after 9d QUV accelerated aging due to the obvious cracks in the foaming cell. In temperature cycling the mechanical properties increased arising from cross linking reaction in the aging process. Besides, the chloride ion penetration resistance of the material was tested by dielectric flux intelligent tester, and the result shows that the material is of excellent chloride ion penetration resistance capability. The infiltration coefficient is 8.1×10-11cm2/s.
Experimental study on chloride ion permeability of Crumb Rubber Concrete
Crumb Rubber Concrete(CRC),also called Rubberized Concrete,is developed by replacing a portion of aggregates with shredded worn-out automobile tire particles in Portland cement concrete.The chloride ion penetration in CRC with different amount of rubber particles up to 100kg/m~3 in volume,is investigated by following the ASTM C 1202-97 method.The results show that the charge passed through CRC is typically in the order of 1000C,and is considered very low according to ASTM C 1202-97 standard.It is noticed that the charge decreases as the crumb rubber increased in CRC.
Recent progress in engineering near-infrared persistent luminescence nanoprobes for time-resolved biosensing/bioimaging
Persistent luminescence nanoprobes (PLNPs) can remain luminescent after ceasing excitation. Due to the ultra-long decay time of persistent luminescence (PersL), autofluorescence interference can be efficiently eliminated by collecting PersL signal after autofluorescence decays completely, thus the imaging contrast and sensing sensitivity can be significantly improved. Since near-infrared (NIR) light shows reduced scattering and absorption coefficient in penetrating biological organs or tissues, near-infrared persistent luminescence nanoprobes (NIR PLNPs) possess deep tissue penetration and offer a bright prospect in the areas of in vivo biosensing/bioimaging. In this review, we firstly summarize the design of different types of NIR PLNPs for biosensing/bioimaging, such as transition metal ions-doped NIR PLNPs, lanthanide ions-doped NIR PLNPs, organic molecules-based NIR PLNPs, and semiconducting polymer self-assembled NIR PLNPs. Notably, organic molecules-based NIR PLNPs and semiconductor self-assembled NIR PLNPs, for the first time, were introduced to the review of PLNPs. Secondly, the effects of different types of charge carriers on NIR PersL and luminescence decay of NIR PLNPs are significantly emphasized so as to build up an in-depth understanding of their luminescence mechanism. It includes the regulation of valence band and conduction band of different host materials, alteration of defect types, depth and concentration changes caused by ion doping, effective radiation transitions and energy transfer generated by different luminescence centers. Given the design and potential of NIR PLNPs as long-lived luminescent materials, the current challenges and future perspective in this rapidly growing field are also discussed.