二维材料复合光纤调制器件研究进展

随着通信技术的快速发展和广泛应用,光纤通信以其高容量和低损耗的优势,已成为现代信息通信的基础。在光纤通信系统中,光调制器是实现光信号调制的关键器件之一,通常基于块状晶体的电学和光电子学器件。然而,这类器件会影响光在高密度传输过程中的质量,限制了光纤通信实现高速和高容量性能的潜力。为了解决这个问题,研究人员一直致力于开发全光纤器件,可以在不中断光纤传输过程的情况下对光信号进行调制、放大和检测。近年来,设计和制造了许多具有不同结构的新型光纤。其中,二维材料在光调制领域引起了人们的广泛关注,因为它们具有可以增强光与物质之间相互作用的独特性质。基于二维材料复合光纤的光纤型调制器有望为光纤通信带来新的机遇。在本文中,我们将介绍将二维材料与不同结构的光纤进行复合的各种方法,例如光纤端面复合、孔内壁复合、拉锥复合和侧剖复合。这些方法可以有效地整合二维材料和光纤的优势,创造出具有高性能和功能性的新型光调制器。我们还将举例介绍一些基于二维材料复合光纤的光调制器,例如基于MoS_(2)的全光波长调制器、基于石墨烯的电光吸收调制器和基于MXene的热光相位调制器。这些器件可以通过利用二维材料的光学、电学或热学性质来调制光信号的波长、强度或相位。这些器件可以通过改变二维材料折射率的实部和虚部来实现对光信号的调制。此外,我们还将总结二维材料复合光纤调制器在不同领域(如全光、电光和热光)的调制原理、过程和应用。我们将与基于块状晶体器件的传统光调制器进行优缺点比较,并讨论它们在提高光纤通信系统性能和效率方面的潜力。最后,我们将讨论二维材料复合光纤领域所面临的机遇和挑战,并提出未来研究方向和发展前景。

Haze Control by Industrialization:A Win-win Mode of Ecological Civilization and Economic Development

Haze control is a difficult and arduous battle,and it is a major decision concerning the people's livelihood and national ecological civilization construction.Taking Heilongjiang Province as an example,this paper introduced a new idea for haze control.Haze in Heilongjiang Province was mainly resulted from straw burning.Market-oriented,large-scale,and industrialized haze control relying on science and technology is new opportunity and challenge for realizing ecological civilization and revitalizing the economy of Heilongjiang Province.

Membrane bioreactors for hospital wastewater treatment: recent advancements in membranes and processes

Discharged hospital wastewater contains various pathogenic microorganisms,antibiotic groups,toxic organic compounds,radioactive elements,and ionic pollutants.These contaminants harm the environment and human health causing the spread of disease.Thus,effective treatment of hospital wastewater is an urgent task for sustainable development.Membranes,with controllable porous and nonporous structures,have been rapidly developed for molecular separations.In particular,membrane bioreactor(MBR)technology demonstrated high removal efficiency toward organic compounds and low waste sludge production.To further enhance the separation efficiency and achieve material recovery from hospital waste streams,novel concepts of MBRs and their applications are rapidly evolved through hybridizing novel membranes(non hydrophilic ultrafiltration/microfiltration)into the MBR units(hybrid MBRs)or the MBR as a pretreatment step and integrating other membrane processes as subsequent secondary purification step(integrated MBR-membrane systems).However,there is a lack of reviews on the latest advancement in MBR technologies for hospital wastewater treatment,and analysis on its major challenges and future trends.This review started with an overview of main pollutants in common hospital wastewater,followed by an understanding on the key performance indicators/criteria in MBR membranes(i.e.,solute selectivity)and processes(e.g.,fouling).Then,an in-depth analysis was provided into the recent development of hybrid MBR and integrated MBR-membrane system concepts,and applications correlated with wastewater sources,with a particular focus on hospital wastewaters.It is anticipated that this review will shed light on the knowledge gaps in the field,highlighting the potential contribution of hybrid MBRs and integrated MBRmembrane systems toward global epidemic prevention.

植物促生芽孢杆菌中新型脂肪酸通过两组分调控系统OmpS/R和毒素转运蛋白介导的“嗜食同类”机制促进生物被膜的形成

当单细胞繁殖进入多细胞水平时,为了应对环境压力,细菌必须进化出维持其群体稳定的作用机制.“嗜食同类”是芽孢杆菌应对环境营养缺乏的一种策略,维持了芽孢杆菌的生存.作为芽孢杆菌的模式种群,枯草芽孢杆菌的“嗜食同类”行为已被广泛研究,但其他芽孢杆菌的“嗜食同类”机制仍然未知.生物被膜是一种被胞外基质包裹的多细胞群体,维持细菌在自然环境中的生存.本研究报道了由贝莱斯芽孢杆菌SQR9合成的新型次级代谢物杆菌酸(bacillunoic acids,BAs)介导的“嗜食同类”行为及机制,以及它对菌株SQR9生物被膜形成的促进作用.菌株SQR9细胞群体分化为两个亚群,一个亚群合成BAs并通过两组分调控系统OmpS-OmpR激活相应免疫基因bnaAB的表达,而不能合成BAs的亚群对该物质敏感.因而,群体中合成BAs的亚群通过该物质裂解部分不合成BAs的同类,由此释放的胞外DNA促进了生物被膜的形成.该研究结果阐明了菌株SQR9群体中的一些细胞如何牺牲自己,从而使群体中其它细胞有更好的机会在环境中存活下来.因此,菌株SQR9群体受益于“嗜食同类”系统.