Molecular machines:from photoresponsive molecules to dynamic materials

Molecular machines are synthetic small molecules that could utilize their mechanical movement triggered by external stimuli to accomplish useful tasks. Since the development of molecular machines towards various applications, the efficiency and robustness of these systems are considered to be of great importance and still somehow very challenging. To some extent, the use of short wavelengths of harmful UV light, low photoefficiency (quantum yield of photoisomerization) as well as low PSD, are limiting the practical application of these photoresponsive systems. Thus, to realize high spatiotemporal control over dynamic properties with large windows of non-invasive operation, the design of new molecular tools in addition to boosting the performance of established molecular motors and switches is a vital challenge to improve the next generation of molecular machines. This dissertation is focused on two of photoresponsive molecular machines, i.e., molecular motors and switches, by taking advantage of their unique properties to control specific functions. The first three research chapters (chapter 2 to chapter 4) are mainly devoted to boosting the performance of light-driven molecular motors and switches by molecular engineering, while the following four chapters are dedicated to controlling molecular motion of light-responsive switches in porous solids or supramolecular systems

Editorial

The journal of Satellite Oceanography and Meteorology (SOM) was launched in 2016 for inspiring and disseminating research papers on theory, science, technology and applications of satellite remote sensing data of the ocean, atmosphere and climate. We welcome research papers in areas of (a) original research results from satellite observations of the regional and global ocean and atmosphere, (b) calibration/validation and research related to future satellite missions, and (c) new satellite-derived products and climate records constructed from satellite observations. We also welcome high-quality research papers in broad research areas including but not limiting to (i) oceanography and marine science; (ii) meteorology and atmospheric science; (iii) air-sea, physical-biological and physical-chemical interactions, and (iv) studies of the Earth’s climate system

Editorial

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Inaugural Editorial

The Satellite Oceanography and Meteorology (SOM) was launched in 2016, in response to the growing use of remotely sensed satellite data in understanding and identifying important processes and phenomena occurring in the atmosphere and ocean. The SOM provides space for oceanographers, meteorologists, hydrologists and climatologists to publish their research papers on theory, science, technology and applications of satellite remote sensing data of the ocean, atmosphere and climate

Enlightening dynamic functions in molecular systems by intrinsically chiral light-driven molecular motors

Chirality is a fundamental property which plays a major role in chemistry, physics, biological systems and materials science. Chiroptical artificial molecular motors (AMMs) are a class of molecules which can convert light energy input into mechanical work, and they hold great potential in the transformation from simple molecules to dynamic systems and responsive materials. Taking distinct advantages of the intrinsic chirality in these structures and the unique opportunity to modulate the chirality on demand, chiral AMMs have been designed for the development of light-responsive dynamic processes including switchable asymmetric catalysis, chiral self-assembly, stereoselective recognition, transmission of chirality, control of spin selectivity and biosystems as well as integration of unidirectional motion with specific mechanical functions. This review focuses on the recently developed strategies for chirality-led applications by the class of intrinsically chiral AMMs. Finally, some limitations in current design and challenges associated with recent systems are discussed and perspectives towards promising candidates for responsive and smart molecular systems and future applications are presented.</p

Storm-induced changes in pCO2 at the sea surface over the northern South China Sea during Typhoon Wutip

In situ oceanographic measurements were made before and after the passage of Typhoon Wutip in September 2013 over the northern South China Sea. The surface geostrophic circulation over this region inferred from satellite altimetry data features a large‐size anticyclonic eddy, a small‐size cyclonic eddy, and smaller‐size eddies during this period. Significant typhoon‐induced changes occurred in the partial pressure of CO2 at the sea surface (pCO2sea) during Wutip. Before the passage of Wutip, pCO2sea was about 392.92 ± 1.83, 390.31 ± 0.50, and 393.04 ± 4.31 μatm over the cyclonic eddy water, the anticyclonic eddy water, and areas outside two eddies, respectively. The entire study region showed a carbon source (1.31 ± 0.46 mmol CO2 m?2 d?1) before Wutip. In the cyclonic eddy water after Wutip, high sea surface salinity (SSS), low sea surface temperature (SST), and high pCO2sea (413.05 ± 7.56 μatm) made this area to be a carbon source (3.30 ± 0.75 mmol CO2 m?2 d?1). In the anticyclonic eddy water after Wutip, both the SSS and SST were lower, pCO2sea was also lower (383.03 ± 3.72 μatm), and this area became a carbon sink (-0.11 ± 0.55 mmol CO2 m?2 d?1), in comparison with the pretyphoon conditions. The typhoon‐induced air‐sea CO2 flux reached about 0.03 mmol CO2 m?2 d?1. Noticeable spatial variations in pCO2sea were affected mainly by the typhoon‐induced mixing/upwelling and vertical stratifications. This study suggests that the local air‐sea CO2 flux in the study region was affected significantly by oceanographic conditions during the typhoon

Editorial-The 6th International Workshop on Modeling the Ocean (IWMO 2014)

The 6th International Workshop on Modeling the Ocean (IWMO 2014) was held on June 23–27, 2014, at Dalhousie University in Halifax, Nova Scotia, Canada. After three meetings in Asia (Oey et al. 2010, 2013a, b) and one in Europe (Berntsen et al. 2014), the IWMO returned to North America for the second time (since IWMO 2010 in the USA; Ezer et al. 2011). Readers are referred to https://www.dal.ca/sites/iwmo. html for more information on IWMO 2014 and http://www. ccpo.odu.edu/POMWEB /meetings.htm for information on the past meetings and future planned meetings

Motorized Photomodulator:Making A Non-photoresponsive Supramolecular Gel Switchable by Light

Introducing photo-responsive molecules offers an attractive approach for remote and selective control and dynamic manipulation of material properties. However, it remains highly challenging how to use a minimal amount of photo-responsive units to optically modulate materials that are inherently inert to light irradiation. Here we show that the application of a light-driven rotary molecular motor as a "motorized photo-modulator" to endow a typical H-bond-based gel system with the ability to respond to light irradiation creating a reversible sol-gel transition. The key molecular design feature is the introduction of a minimal amount (1 mol%) of molecular motor into the supramolecular network as a photo-switchable non-covalent crosslinker. Advantage is taken of the subtle interplay of the large geometry change during photo-isomerization of the molecular motor guest and the dynamic nature of a supramolecular gel host system. As a result, a tiny amount of molecular motors is enough to switch the mechanical modulus of the entire supramolecular systems. This study proves the concept of designing photo-responsive materials with minimum use of non-covalent light-absorbing units.</p