Photophysics of metal-organic frameworks:A brief overview

Metal-organic frameworks(MOFs),which are self-assembled porous coordination materials,have garnered considerable attention in the fields of optoelectronics,photovoltaic,photochemistry,and photocatalysis due to their diverse structures and excellent tunability.However,the performance of MOF-based optoelectronic applications currently falls short of the industry benchmark.To enhance the performance of MOF materials,it is imperative to undertake comprehensive investigations aimed at gaining a deeper understanding of photophysics and sequentially optimizing properties related to photocarrier transport,recombination,interaction,and transfer.By utilizing femtosecond laser pulses to excite MOFs,time-resolved optical spectroscopy offers a means to observe and characterize these ultrafast microscopic processes.This approach adds the time coordinate as a novel dimension for comprehending the interaction between light and MOFs.Accordingly,this review provides a comprehensive overview of the recent advancements in the photophysics of MOFs and additionally outlines potential avenues for exploring the time domain in the investigation of MOFs.

An improved apparent permeability model considering full pore pressure range,variable intrinsic permeability and slippage coefficient

Although the slippage effect has been extensively studied,most of the previous studies focused on the impact of the slippage effect on apparent permeability within a low pore pressure range,resulting in the inability of matching the evolution of permeability in the remaining pressure range.In this paper,a new apparent permeability model that reveals the evolution of permeability under the combined action of effective stress and slippage in the full pore pressure range was proposed.In this model,both intrinsic permeability and slippage coefficient are stress dependent.Three experimental tests with pore pressure lower than 2 MPa and a test with pore pressure at about 10 MPa using cores from the same origin under constant confining stress and constant effective stress are conducted.By comparing experimental data and another apparent permeability model,we proved the fidelity of our newly developed model.Furthermore,the contribution factor of the slippage effect Rslip is used to determine the low pore pressure limit with significant slippage effect.Our results show that both narrow initial pore size and high effective stress increase the critical pore pressure.Finally,the evolutions of the slippage coefficient and the intrinsic permeability under different boundary conditions were analyzed.

Survey on Fertility of Tea Garden Soil in Meizhou Region

Survey on fertility of tea garden soil in Meizhou region indicates that tea garden soil has strong acidity; organic matter content remains at medium level; there is a severe lack of available content of nitrogen(N),phosphorus(P) and potassium(K); available calcium(Ca) and magnesium(Mg) content is also insufficient; available sulfur(S) is abundant. In the management of tea cultivation,it is recommended to supplement organic fertilizer,balance the application of NPK fertilizer,and adequately alleviate shortage of Ca and Mg element,to guarantee high and stable yield of tea.

Metal−Organic Framework-Based Ultrafast Logic Gates for High-Security Optical Encryption

Optical logic gates call for materials with giant optical nonlinearity to break the current performance bottleneck.Metal–organic frameworks(MOFs)provide an intriguing route to achieve superior optical nonlinearity benefitting from structural diversity and design flexibility.However,the potential of MOFs for optoelectronics has been largely overlooked and their applications in optical logic have not been exploited.Here,through temporally manipulating the nonlinear optical absorption process in porphyrin-based MOFs,we have successfully developed AND and XOR logic gates with an ultrafast speed approaching 1 THz and an on–off ratio above 90%.On this basis,all-optical information encryption is further demonstrated using transmittance as primary codes,which shows vast prospects in avoiding the disclosure of security information.To the best of our knowledge,this is the first exploration of MOFs for applications in ultrafast optical logic devices and information encryption.

LOX-less大麦麦芽对麦汁和啤酒风味稳定性的影响

本工作主要研究了LOX—less大麦麦芽对麦汁和啤酒质量的影响，尤其对啤酒风味稳定性的影响。研究中以AC Metcalfe麦芽作为对照，分别将其与LOX-less大麦麦芽应用于半工业规模（1000L）的酿造试验中,结果明确显示．与AC Metcalfe对照麦芽相比LOX—less麦芽具有较低的壬烯醛潜在性,尽管这两种麦芽的LOX活性已经处于相对较低水平。相同酿造条件下，LOX—less麦芽酿造的啤酒中反-2-壬烯醛（T2N）和1-戊基丁内酯的含量与AC Metcalfe对照麦芽酿制的啤酒相比更低，尤其是在啤酒老化（强制或自然）后．这也与一般风味描述的感官品评结果取得了良好的一致性，品评中LOX—lcss麦芽酿制的啤酒新鲜度得分高于对照麦芽，并在强制老化后更加明显。此外，LOX—less麦芽酿制的啤酒具有更好的泡沫稳定性，将近高出30S（N1BEM法测试），这些结果证实使用LOX—less大麦麦芽有益于提高啤酒的风味稳定性和泡沫稳定性.

All-optical control of exciton flow in a colloidal quantum well complex

Excitonics,an alternative to romising for processing information since semiconductor electronics is rapidly approaching the end of Moore’s law.Currently,the development of excitonic devices,where exciton flow is controlled,is mainly focused on electric-field modulation or exciton polaritons in high-Q cavities.Here,we show an alloptical strategy to manipulate the exciton flow in a binary colloidal quantum well complex through mediation of the Förster resonance energy transfer(FRET)by stimulated emission.In the spontaneous emission regime,FRET naturally occurs between a donor and an acceptor.In contrast,upon stronger excitation,the ultrafast consumption of excitons by stimulated emission effectively engineers the excitonic flow from the donors to the acceptors.Specifically,the acceptors’stimulated emission significantly accelerates the exciton flow,while the donors’stimulated emission almost stops this process.On this basis,a FRET-coupled rate equation model is derived to understand the controllable exciton flow using the density of the excited donors and the unexcited acceptors.The results will provide an effective alloptical route for realizing excitonic devices under room temperature operation.