Recent Advances in Visible-Light-Driven Photoelectrochemical Water Splitting: Catalyst Nanostructures and Reaction Systems

Photoelectrochemical(PEC) water splitting using solar energy has attracted great attention for generation of renewable hydrogen with less carbon footprint, while there are enormous challenges that still remain for improving solar energy water splitting efficiency, due to limited light harvesting, energy loss associated to fast recombination of photogenerated charge carriers, as well as electrode degradation. This overview focuses on the recent development about catalyst nanomaterials and nanostructures in different PEC water splitting systems. As photoanode, Au nanoparticle-decorated TiO_2 nanowire electrodes exhibited enhanced photoactivity in both the UV and the visible regions due to surface plasmon resonance of Au and showed the largest photocurrent generation of up to 710 nm. Pt/Cd S/CGSe electrodes were developed as photocathode. With the role of p–n heterojunction, the photoelectrode showed high stability and evolved hydrogen continuously for more than 10 days. Further, in the Z-scheme system(Bi_2S_3/TNA as photoanode and Pt/Si PVC as photocathode at the same time), a self-bias(open-circuit voltage Voc= 0.766 V) was formed between two photoelectrodes, which could facilitate photogenerated charge transfers and enhance the photoelectrochemical performance, and which might provide new hints for PEC water splitting. Meanwhile, the existing problems and prospective solutions have also been reviewed.

Preparation and promising optoelectronic applications of lead halide perovskite patterned structures:A review

Lead halide perovskites have received considerable attention from researchers over the past several years due to their superior optical and optoelectronic properties,because of which they can be a versatile platform for fundamental science research and applications.Patterned structures based on lead halide perovskites have much more novel properties compared with their more commonly seen bulk-,micro-,and nano-crystals,such as improvement in antireflection,light-scattering effects,and light absorption,as a result of their adjustability of spatial distributions.However,there are many challenges yet to be resolved in this field,such as insufficient patterned resolution,imperfect crystal quality,complicated preparation process,and so on.To pave the way to solve these problems,we provide a systematic presentation of current methods for fabricating lead halide perovskite patterned structures,including thermal imprint,use of etching films,two-step vapor-phase growth,template-confined solution growth,and seed-assisted growth.Furthermore,the advantages and disadvantages of these methods are elaborated in detail.In addition,thanks to the extraordinary properties of lead halide perovskite patterned structures,a variety of potential applications in optics and optoelectronics of these structures are described.Lastly,we put forward existing challenges and prospects in this exciting field.

Trajectory Tracking of Quadrotor Aerial Robot Using Improved Dynamic Inversion Method

This paper presents trajectory tracking control works concerning quadrotor aerial robot with rigid cross structure. The quadrotor consists of four propellers which are two paired clockwise rotate and anticlockwise rotate. A nonlinear dynamic model of the quadrotor is provided, and a controller based on the improved dynamic inverse is synthesized for the purpose of stabilization and trajectory tracking. The proposed control strategy has been tested in simulation that can balance the deviation of model inaccuracy well.

Progress in the Pathogenesis and Treatment of Heart Failure with Preserved Ejection Fraction

Heart failure with preserved ejection fraction(HFpEF)is a special and common clinical heart failure with left ventricular diastolic dysfunction.It has attracted much attention at home and abroad in recent years because of its high heterogeneity and complex pathogenesis.Compared with heart failure with reduced ejection fraction(HFrEF),HFpEF has complex clinical manifestations,many complications,limited clinical treatment,and poor prognosis.In recent years,the research on the pathogenesis and treatment of HFpEF has made certain progress,but there are no specific guidelines for clinical practice.By combing the latest research at home and abroad,the pathogenesis and treatment of HFpEF are systematically reviewed in order to provide a relevant basis for reference its clinical treatment.

迁地保护:从植物活体保存到种子库

随着全球气候变化的加剧和人为活动影响愈加频繁,很多植物物种的栖息地快速缩小,生物多样性面临前所未有的危机。中国是世界上植物多样性最丰富的国家之一,根据生态环境部与中国科学院2023年5月22日联合发布的《中国生物多样性红色名录》,我国有高等植物39,330多种,其中约10%的物种受到威胁。

Thinner 2D α-MoO_(3) makes setting up memristors easier

Two-dimensional(2D)metal oxide α-MoO_(3) shows great potentials because of its very high dielectric constant,air stability and anisotropic phonon polaritons.However,a method to produce ultrathin single crystallineα-MoO_(3) with high transferability for functional device architecture is lacking.Herein,we report on the controllable synthesis of ultrathinα-MoO_(3) single crystals via chemical vapor deposition(CVD)assisted by plasma pretreatment.We also carried out systematic computational work to explicate the mechanism for the slantly-oriented growth of thin nanosheets on plasma-pretreated substrate.The method possesses certain universality to synthesize other ultrathin oxide materials,such as Bi_(2)O_(3) and Sb_(2)O_(3) nanosheets.As-grownα-MoO_(3) presents a high dielectric constant(≈40),ultrathin thickness(≈3 nm)and high transferability.Memristors withα-MoO_(3) as the functional layers show excellent performance featuring high on/off ratio of approximately 104,much lower set voltage around 0.5 V,and highly repetitive voltage sweep endurance.The power consumption of MoO_(3) memristors is significantly reduced,resulted from reduced thickness of the MoO_(3) nanosheets.Single crystal ultrathinα-MoO_(3) shows great potentials in post-Moore memristor and the synthesis of CVD assisted by plasma pretreatment approach points to a new route for materials growth.

《国家重点保护野生植物名录》调整的必要性、原则和程序

我国是世界上植物多样性最丰富的国家之一, 1999年发布的《国家重点保护野生植物名录》(下称《名录》(第一批))明确了国家重点保护野生植物的范围,为依法强化保护、规范无序开发利用、提高公众保护意识奠定了基础。20多年来,我国野生植物多样性保护形势发生了很大变化,需要对《名录》进行调整。2018年,国家林业和草原局、农业农村部启动《名录》调整工作,物种的遴选遵循了5条基本原则和4条补充性原则,这些原则主要涉及中国珍稀濒危物种,具有重要经济、文化、科研、生态等价值物种的入选以及部分物种的排除。经国务院批准,2021年9月7日,国家林业和草原局、农业农村部发布了调整后的《名录》,包括真菌类、藻类、苔藓、石松类和蕨类植物、裸子植物和被子植物,共计约1,101种(455种和40类)野生植物列入其中。本文简要介绍了《名录》调整的必要性、原则和程序及调整后的情况。

Nanoparticle-immersed paper imprinting mass spectrometry imaging reveals uptake and translocation mechanism of pesticides in plants

Design and discovery of carrier-mediated modified pesticides are vital for reducing pesticide dosage and increasing utilization,yet it remains a great challenge due to limited insights into plant translocation mechanisms.Nanostructure/nanoparticle assisted laser desorption/ionization strategy has established itself as a preferential analytical tool for biological tissue analysis,whereas potential applications in plant sciences are hindered with regard to the inability to slice plant leaves and petals.Herein,we report gold nanoparticle(AuNP)-immersed paper imprinting mass spectrometry imaging(MSI)for the spatiotemporal visualization of pesticide translocation in plant leaves.This approach plays a dual role in preserving spatial information and improving ionization efficiency for pesticides regardless of imaging artifacts due to homogenous AuNP deposition.Using this MSI platform,we proposed the elaborate plant translocation mechanism of agrochemicals for the first time,which is currently poorly understood.The dynamic processes of carrier-mediated pesticides can be clearly visualized,including crossing of plasma membranes by transporters,translocation downward in stems through the phloem,diffusion to the xylem and,conversely,accumulation at margins of the treated leaves.Moreover,this AuNP-assisted paper imprinting method could be highly compatible with laser-based MSI instruments,expediting researches across a broad range of fields,especially in nanomaterial development and life sciences.

Catalytic activity of porous manganese oxides for benzene oxidation improved via citric acid solution combustion synthesis

Various manganese oxides(MnOx) prepared via citric acid solution combustion synthesis were applied for catalytic oxidation of benzene. The results showed the ratios of citric acid/manganese nitrate in synthesizing process positively affected the physicochemical properties of MnOx, e.g., BET(Brunauer-Emmett-Teller) surface area, porous structure, reducibility and so on, which were in close relationship with their catalytic performance. Of all the catalysts, the sample prepared at a citric acid/manganese nitrate ratio of 2:1(C2M1) displayed the best catalytic activity with T(90)(the temperature when 90% of benzene was catalytically oxidized) of 212 ℃. Further investigation showed that C2M1 was Mn2O3 with abundant nano-pores, the largest surface area and the proper ratio of surface Mn^4+/Mn^3+, resulting in preferable low-temperature reducibility and abundant surface active adsorbed oxygen species. The analysis results of the in-situ Fourier transform infrared spectroscopy(in-situ FTIR) revealed that the benzene was successively oxidized to phenolate, o-benzoquinone, small molecules(such as maleates, acetates, and vinyl), and finally transformed to CO2 and H2O.

MicroRNA Signaling Pathway Network in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma （PDAC） is considered to be the most lethal and aggressive malignancy with high mortality and poor prognosis. Their responses to current mnltimodal therapeutic regimens are limited. It is urgently needed to identify the molecular mechanism underlying pancreatic oncogenesis. Twelve core signaling cascades have been established critical in PDAC tumorigenesis by governing a wide variety of cellular processes. MicroRNAs （miRNAs） are aberrantly expressed in different types of tumors and play pivotal roles as post-transcriptional regulators of gene expression, Here, we will describe how miRNAs regulate different signaling pathways that contribute to pancreatic oncogenesis and progression,

Performance of steel bridge deck pavement structure with ultra high performance concrete based on resin bonding

This research investigated a pavement system on steel bridge decks that use epoxy resin(EP)bonded ultra-high performance concrete(UHPC).Through FEM analysis and static and dynamic bending fatigue tests of the composite structure,the influences of the interface of the pavement layer,reinforcement,and different paving materials on the structural performance were compared and analyzed.The results show that the resin bonded UHPC pavement structure can reduce the weld strain in the steel plate by about 32%and the relative deflection between ribs by about 52%under standard axial load conditions compared to traditional pavements.The EP bonding layer can nearly double the drawing strength of the pavement interface from 1.3 MPa,and improve the bending resistance of the UHPC structure on steel bridge decks by about 50%;the bending resistance of reinforced UHPC structures is twice that of unreinforced UHPC structure,and the dynamic deflection of the UHPC pavement structure increases exponentially with increasing fatigue load.The fatigue life is about 1.2×10^(7) cycles under a fixed force of 9 kN and a dynamic deflection of 0.35 mm,which meets the requirements for fatigue performance of pavements on steel bridge decks under traffic conditions of large flow and heavy load.

Effect of superabsorbent polymer on mechanical properties of cement stabilized base and its mechanism

Superabsorbent polymers(SAPs)are cross-linked polymers that can absorb and retain large amounts of water.In recent years,a growing interest was seen in applying SAPs in concrete to improve its performance due to its efficiency in mitigating shrinkage.This paper presents findings in a study on effect of SAPs on performance of cement-treated base(CTB),using the experience of internal curing of concrete.CTB specimens with and without SAPs were prepared and tested in the laboratory.Tests conducted include mechanical property testing,dry shrinkage testing,differential thermal analysis,mercury intrusion porosimetry and scanning electron microscope testing.It was found that 7-day and 28-day unconfined compressive strength of CTB specimens with SAPs was higher than regular CTB specimens.28d compressive strength of CTB specimens with SAPs made by Static pressure method was 5.87 MPa,which is 27%higher than that of regular CTB specimens.Drying shrinkage of CTB specimens with SAPs was decreased by 52.5%comparing with regular CTB specimens.Through the microstructure analysis it was found that CTB specimens with SAPs could produce more hydration products,which is also the reason for the strength improvement.

Radiation model of a xenon flash lamp in a laser amplifier pump cavity

Understanding the radiation model of a flash lamp is essential for the reflector design of a laser amplifier. Reflector design often involves several simplifying assumptions, like a point or Lambertian source; either of these assumptions may lead to significant errors in the output distribution. In practice, source non-idealities usually result in sacrificing the amplifier's gain coefficient. We propose a novel test technique for attaining the xenon flash lamp absolute spectral intensity at various angles of view, and then accurately predict radiation distributions and generate the reflector shape. It is shown that due to the absorption of emitted radiation by the lamp itself, the behavior of the radiation model at various wavelengths is different. Numerical results of xenon plasma absorption coefficient were compared with the measured data. A reasonable agreement was obtained for the absorption coefficient parameters. Thus, this work provides a useful analytical tool for the engineering design of laser amplifier reflectors using xenon flash lamps as pumps.

The spatial distribution of threats to plant species with extremely small populations

Many biological conservationists take actions to conserve plant species with extremely small populations （PSESP） in China; however, there have been few studies on the spatial distribution of threats to PSESP. Hence, we selected distribution data of PSESP and made a map of the spatial distribution of threats to PSESP in China. First, we used the weight assignment method to evaluate the threat risk to PSESP at both country and county scales. Second, we used a geographic information system to map the spatial distribution of threats to PSESP, and explored the threat factors based on linear regression analysis. Finally, we suggested some effective conservation options. We found that the PSESP with high values of protection, such as the plants with high scientific research values and ornamental plants, were threatened by over-exploitation and utilization, habitat fragmentation, and a small sized wild population in broad-leaved forests and bush fallows. We also identified some risk hotspots for PSESP in China. Regions with low elevation should be given priority for ex- and in-situ conservation. Moreover, climate change should be considered for conservation of PSESP. To avoid intensive over-exploitation or utilization and habitat fragmentation, in-situ conservation should be practiced in regions with high temperatures and low temperature seasonality, particularly in the high risk hotspots for PSESP that we proposed. Ex-situ conservation should be applied in these same regions, and over-exploitation and utilization of natural resources should be prevented. It is our goal to apply the concept of PSESP to the global scale in the future.

Effect of alumina and zirconia as binders on the activity of Fe-BEA for NH3-SCR of NO

Fe-BEA catalysts are active for the NH3-SCR of NO. For industrial application, a binder should be added to the Fe-BEA catalysts to make them tightly adhere to the monoliths. The addition of alumina and zirconia as binders to the Fe-BEA led to a different effect on NO conversion. The catalytic activity of the mixed samples was evaluated by the temperature programmed procedure in a flow-reactor sys!em, and themechaism was. analyzedvia SEM, BET, andXPS. Itwas found that larger ironparticles were tbrmed by the migration orparent tron pamcles in the Fe-BEA catalyst with alumina. This led to the increase of Fe3＋ magnitude and iron cluster, enhancing the abilities of NO oxidation and storage. Accordingly, the SCR activity increased slightly in low temperature but decreased sharply in high temperature. For the Fe-BEA with zirconia sample, NO oxidation and storage abilities decreased due to the less iron clusters. The increase of Fe ＋ magnitude resulted in higher catalytic oxidation ability, which gave rise to little change in the SCR activity compared with the Fe-BEA.

RE-NiO_(x)(RE=Ce,Y,La)composite oxides coupled plasma catalysis for benzene oxidation and by-product ozone removal

Plasma-coupled catalysis is a promising volatile organic co mpounds(VOCs) removal technology because of its interactional principles of plasma decomposition and catalytic oxidation.However,the problem of harmful by-products is still in trouble.A series of rare earth doped RE-NiO_(x)(RE=Ce,Y,La) composite oxides were synthesized by metal organic frameworks(MOFs)-derived method for coupled plasma oxidation of benzene and by-product ozone removal.Compared with plasma alone,the 1%La-NiO_(x)catalyst shows the best enhancement of 50% for benzene conversion with complete removal of a maximum of 800 ppm ozone.The energy consumption for 90% benzene removal efficiency(η90%) is also reduced from 3600 to 1200 J/L.Characterization re sults of RE-NiO_(x) catalysts indicate that the doping of La causes interaction and synergistic effect between La and Ni,and the surface oxygen and lattice oxygen with defects play crucial roles in benzene oxidation and ozone decomposition,respectively.In addition,the decomposition mechanism of benzene and ozone under plasma is proposed.Plasma is responsible for the indiscriminate bond breaking in benzene and oxygen to form a variety of organic intermediates and ozone,while the La-NiO_(x) catalyst selectively oxidizes the intermediates to CO_(x)/H2O and decomposes the ozone into oxygen.

Explicitly Reconstructing RAMI-V Scenes for Accurate 3-Dimensional Radiative Transfer Simulation Using the LESS Model

Radiative transfer(RT)simulation based on reconstructed 3-dimensional(3D)vegetation scenarios can promote the validation and development of various retrieval algorithms to monitor the growing states of vegetation in large-scale,multi-angular,and multi-sensor ways.The radiation transfer model intercomparison(RAMI)has made great contributions to providing abstract and actual 3D vegetation scenarios,and to the benchmarking of RT models under developed evaluation systems.To date,RAMI has been updated to the fifth phase(RAMI-V).In this study,we try to implement explicit conversion from all the RAMI-V scenes to generic structural models in the Wavefront OBJ format.These reconstructed scenes are applied in the LESS RT model to probe the ability of its RT solvers to simulate all sorts of remote sensing observations and radiative budget,including the bidirectional reflectance factor(BRF),albedo,fraction of photosynthetically active radiation absorbed by vegetation,and threshold hemispherical photograph(THP).BRF simulations fully explain angle effects as well as variation and robustness of the normalized difference vegetation index.Energy conservation is well validated between simulated absorption and albedo.The gap fraction derived from THP is analyzed in directional and total situations.In addition,this paper guides us how to simplify basic geometries and tune the illumination resolution(0.02 is optimal)to balance the simulation accuracy and efficiency.The generic structural models and reliable simulation results can be referenced by other RT models and retrieval algorithms.