Activation of hematite photoanode synthesized at low temperature by W doping

1.Introduction Solar water splitting offers a promising approach for green hydrogen production[1].There are many ways to achieve solar water splitting,such as photocatalytic(PC)water splitting,photoelectrochemical(PEC)water splitting,and photovoltaicelectrocatalytic(PV-EC)water splitting[2].

Tip-induced directional charge separation on one-dimensional BiVO4 nanocones for asymmetric light absorption

One dimensional(1D)semiconductor is a class of extensively attractive materials for many emerging solar energy conversion technologies.However,it is still of shortage to assess the impact of 1D structural symmetry on spatial charge separation and understand its underlying mechanism.Here we take controllably-synthesized 1D BiVO_(4)nanocones and nanorods as prototypes to study the influence of 1D symmetry on charge separation.It is found that the asymmetric BiVO_(4)nanocones enable more effective charge separation compared with the symmetric nanorods.The unexpected spatial charge separation on the nanocones is mainly ascribed to uneven light absorption induced diffusion-controllable charge separation due to symmetry breaking of 1D nanostructure,as evidenced by spatial and temporal resolved spectroscopy.Moreover,the promotion effect of charge separation on the nanocones was quantitatively evaluated to be over 20 times higher than that in BiVO_(4)nanorods.This work gives the first demonstration of the influence of 1D structural symmetry on the charge separation behavior,providing new insights to design and fabricate semiconductor materials for efficient solar energy conversion.

Liquid-holdup regions research of novel reactive distillation column for C5 fraction separation

Recent advances in technologies of reactive distillation(RD) offer various design concepts for chemical processes.For separation of cracking C5 fraction, one of the main challenges is improving the conversion of cyclopentadiene(CPD) and the recovery of isoprene(IP). In the current work, a novel reactive distillation column with several liquid-holdup regions was designed, since it allows long residence time and provides flexibility for narrowing the efficiency gap between reaction and distillation. By use of Aspen Plus, a corresponding mathematic model was established and verified to be accurate. Following that, comprehensive studies were carried out for the design of liquid-holdup regions position. Details and principles about the separation performance with the liquid-holdup regions were revealed and optimized parameters were determined with 100 theoretical plates,feed position of 35 th plate, and four liquid-holdup regions at 25 th, 60 th, 75 th and 90 th plate. The designed RD column could well meet the technical requirement, and influence of other important factors including residence time, operating pressure and reflux ratio was further investigated.

微秒时间分辨的工况电化学紫外可见吸收光谱测量系统

工况光谱表征技术是深入理解电催化反应机理的有效手段,但是目前所使用的大多数工况表征技术都是基于(准)稳态的光谱技术,对发生在毫微秒时间尺度的瞬态变化过程很难直接进行观测。本研究通过在时间分辨紫外可见吸收光谱系统中引入电压脉冲,并在时间上同步电脉冲信号与光谱信号,实现了时间分辨率高达3μs的工况电化学紫外可见吸收光谱测量系统。利用此光谱系统和方法研究了水合铁等电催化剂的水氧化动力学机理,直接揭示了电催化剂表面水氧化中间物种在毫微秒时间尺度的形成、转化和反应动力学。微秒时间分辨的工况电化学紫外可见吸收光谱,可以促进电催化反应动力学机理的研究和认识,指导新型高效电催化剂的设计合成。

Fe_(3)O_(4) nanoparticles encapsulated in graphitized and inplane porous carbon nanocages derived from emulsified asphalt for a high-performance lithium-ion battery anode

In this work,C@Fe_(3)O_(4) composites were prepared through a typical template method with emulsified asphalt as carbon source,ammonium ferric citrate as transition metal oxide precursor,and NaCl as template.As an anode for lithium-ion batteries,the optimized C@Fe_(3)O_(4)-1:2 composite exhibits an excellent reversible capacity of 856.6 mA·h·g^(-1)after 100 cycles at 0.1A·g^(-1)and a high capacity of 531.1mA·h·g^(-1)after 300 cycles at 1 A·g^(-1),much better than those of bulk carbon/Fe_(3)O_(4) prepared without NaCl.Such remarkable cycling performance mainly benefits from its well-designed structure:Fe_(3)O_(4) nanoparticles generated from ammonium ferric citrate during pyrolysis are homogenously encapsulated in graphitized and in-plane porous carbon nanocages derived from petroleum asphalt.The carbon nanocages not only improve the conductivity of Fe_(3)O_(4),but also suppress the volume expansion of FesO4 effectively during the charge discharge cycle,thus delivering a robust electrochemical stability.This work realizes the high value-added utilization of low-cost petroleum asphalt,and can be extended to application of other transition-metal oxides-based anodes.

A genome-wide landscape of mRNAs,lncRNAs,and circRNAs during subcutaneous adipogenesis in pigs

Background: Preadipocyte differentiation plays a critical role in subcutaneous fat deposition in pigs.However,the roles of different RNAs,such as messenger RNAs(mRNAs),long non-coding RNAs(lncRNAs),and circular RNAs(circRNAs) in the differentiation process of subcutaneous preadipocytes,are still largely unclear.In the present study,a transcriptome analysis,including the analysis of mRNAs,lncRNAs,and circRNAs,during different differentiation stages,namely,day 0(D0),day 2(D2),day 4(D4),and day 8(D8),of subcutaneous preadipocytes from Chinese Erhualian pigs was performed.Results: A total of 1554,470,1344,1777,and 676 differentially expressed(DE) mRNAs,112,58,95,136,and 93 DE lncRNAs,and 902,787,710,932,and 850 DE circRNAs were identified between D2 and D0,between D4 and D2,between D8 and D4,between D4 and D0,and between D8 and D0,respectively.Furthermore,functional enrichment analysis showed that the common DE mRNAs during the entire differentiation process were mainly involved in lipid metabolic and cell differentiation processes.Additionally,co-expression network analysis identified the potential lncRNAs related to adipogenesis,e.g.,MSTRG.131380 and MSTRG.62128.Conclusions: Our study provides new insights of the expression changes of RNAs during adipogenic differentiation,which might contribute to the phenotype of subcutaneous adipogenesis.These results greatly improve our understanding of the molecular mechanisms regulating subcutaneous fat deposition in pigs.

An Improved Deep Learning Model for Predicting DNA Sequence Function

Since a complete DNA chain contains a large data (usually billions of nucleotides), it’s challenging to figure out the function of each sequence segment. Several powerful predictive models for the function of DNA sequence, including, CNN (convolutional neural network), RNN (recurrent neural network), and LSTM [1] (long short-term memory) have been proposed. However, all of them have some flaws. For example, the RNN can hardly have long-term memory. Here, we build on one of these models, DanQ, which uses CNN and LSTM together. We extend DanQ by developing an improved DanQ model and applying it to predict the function of DNA sequence more efficiently. In the most primitive DanQ model, the regulatory grammar is learned by the regulatory motifs captured by the convolution layer and the long-term dependencies between the motifs captured by the recurrent layer, so as to increase the prediction accuracy. Through the testing of some models, DanQ has greatly improved in some indicators. For the regulatory markers, DanQ achieves improvements above 50% of the area under the curve, via the measurement of the precision-recall curve.

A simple vacuum sample chamber for small-angle X-ray scattering at Beijing synchrotron radiation facility

Objective A vacuum sample chamber for SAXS measurement of solutions was developed to improve the signal-to-noise ratio of the instrument at Beijing Synchrotron Radiation Facility(BSRF).Methods We developed a vacuum sample chamber which could be connected to the upstream and the downstream vacuum tubes by bellows.Horizontal and vertical linear slides were mounted in the vacuum chamber to adjust the sample position by 35 mm in the horizontal and vertical directions to align the sample in the light path.The liquid sample holder of the chamber was sealed with polyimide film by squeezing instead of gluing to avoid the potential influence of sealant on the solution.Results The chamber had been used for SAXS measurements of water and bovine serum albumin solution at BSRF.The results showed that the background scattering intensity in air was much higher than that in vacuum,especially in the smallangle area near the beamstop.When the q value is 0.142 nm−1,1.01 nm−1 and 1.25 nm−1,the background scattering intensity in air is 45,6.8 and 4.6 times of that in vacuum,respectively.And the background-subtracted scattering curves of bovine serum albumin solution(10 mg/ml)in air and vacuum differ in intensity by a factor of about 2.When the q value is 2 nm−1,the signal-to-noise ratios of scattering intensity of BSA in air and vacuum are 0.79 and 8.51,respectively.Conclusion We designed a simple vacuum sample chamber to be used on the SAXS instrument at 1W2A station of BSRF.The scattering of the background and protein solution in air and vacuum was tested and compared,and the signal-to-noise ratio was clearly improved.

Call for joint international actions to improve scientific understanding and address soil erosion and riverine sediment issues in mountainous regions

During the International Workshop on Soil Erosion and Riverine Sediment in Mountainous Regions held in November 2022,scientists from many countries shared their state-of-the-art knowledge and brainstormed to improve scientific understanding for coping with climate change and anthropogenic impacts.Information summarized in this discussion includes proposed key scientific questions and suggested joint actions to reduce soil erosion and riverine sediment problems in mountainous regions.

吉祥符号与乡村文化空间

乡村文化空间是具有系统化、整体化和生态化的综合体,乡村文化的构成要素由物质性和非物质性两大部类组成,作为非物质形态的吉祥符号是乡村文化空间重要的构成要素之一。具体表现为文化景观、文化场所和文化活动中的吉祥符号三个方面,因其具有的规律化、秩序化、程式化和审美化等特点,被广泛应用于乡村文化空间之中,并在民俗文化活动中形成了具有活化意义的符号。

Minimal wave speed of a diffusive SIR epidemic model with nonlocal delay

This paper is concerned with the minimal wave speed in a diffusive epidemic model with nonlocal delays.We define a threshold.By presenting the existence and the nonexistence of traveling wave solutions for all positive wave speed,we confirm that the threshold is the minimal wave speed of traveling wave solutions,which models that the infective invades the habitat of the susceptible.For some cases,it is proven that spatial nonlocality may increase the propagation threshold while time delay decreases the threshold.

Effect of exercise on inhibitory control is dose-dependent for adolescents

Adolescence is an important stage for brain maturation.To investigate the effect of different exercise doses on inhibitory control in adolescents aged 12 to 14-year old,an after-school exercise program was offered 5 days per week for 12 weeks during a school semester.Thirsty-four adolescents(17 boys)from the first six classes were randomly divided into low-dose exercise group(LE group,one 30-min aerobic exercise bout per day,n=16)and high-dose exercise group(HE group,two 30-min aerobic exercise bouts per day,n=18),while 23 adolescents(10 boys)in the control group(CON,zero 30-min exercise bout,n=23)were from the last two classes.All the participants in different classes received the same physical education with the same contents,duration,and intensity at class.All the participants completed flanker tests and cardiorespiratory tests before and after exercise intervention.The HE group showed more significant improvements on inhibitory control and VO_(2peak)than CON(p<0.05).Changes in physical activity(PA)were significantly correlated with changes in interference scores(Spearman rho=-0.30,p<0.05),VO_(2peak)(Spearman rho=0.31,p<0.05),and BF percentage(Spearman rho=-0.32,p<0.05).This study demonstrated that effect of exercise on inhibitory control in adolescents is dose-dependent,which highlights the need to focus on the exercise dose in daily life for improving cognition among adolescents.