Common Transceiver LIF⁃Lidar Based on Y⁃Type Optical Fiber for Marine Oil Spill Detection

This paper presents a novel laser⁃induced fluorescence(LIF)Lidar system for marine oil spilling detection.A bifurcated Y⁃type optical fiber and an optical collimating lens compose a coaxial configuration transceiver for this LIF⁃Lidar system.This LIF⁃Lidar system was further applied to measure the excitation spectra from floating oil slicks with different thicknesses on top of seawater at different distances.The system presents several advantages such as compact structure,stable optical path,and convenient operation,which offers a wide application prospect in ocean exploration.

Adhesive anastomosis for organ transplantation

The recent development of tough tissue adhesives has stimulated intense interests among material scientists and medical doctors.However,these adhesives have seldom been tested in clinically demanding surgeries.Here we demonstrate adhesive anastomosis in organ transplantation.Anastomosis is commonly conducted by dense sutures and takes a long time,during which all the vessels are occluded.Prolonged occlusion may damage organs and even cause death.We formulate a tough,biocompatible,bioabsorbable adhesive that can sustain tissue tension and pressurized flow.We expose the endothelial surface of vessels onto a gasket,press two endothelial surfaces to the adhesive using a pair of magnetic rings,and reopen the bloodstream immediately.The time for adhesive anastomosis is shortened compared to the time for sutured anastomosis.We have achieved adhesive anastomosis of a great vein in transplanting the liver of a pig.After the surgery,the adhesive is absorbed,the vein heals,and the pig lives for over one month.

The Interactive Impact of Trade Policy Uncertainty and Credit Constraint Heterogeneity on Firms' Export Margins: Theory and Empirics

This paper develops a simple trade model of heterogeneous firms, which incorporates the dual heterogeneity of credit constraints at the firm and industry levels and reveals the effects of the interaction mechanisms of trade policy uncertainty and credit constraint heterogeneity on exporters’ behaviour. The model confirms that the higher the level of industrial credit constraints, the greater the interaction of trade policy uncertainty and credit constraint heterogeneity, but firms with lower levels of credit constraints within a specific industry are more affected by this interaction. Then, based on the highly dis-aggregated trade data of China’s firms from 2000 to 2013, this paper provides empirical evidence for the main predictions and mechanisms of the theoretical model.