N-Exponential Fertilization Could Affect the Growth and Nitrogen Accumulation of Metasequoia glyptostroboides Seedling in a Greenhouse Environment

Metasequoia glyptostroboides(M.glyptostroboides)is a unique plant species related to relic flora in China.It plays a positive role in afforestation and its long-term protection with high paleoclimate research value.However,due to the nutrients-supply deficiency,it is a big challenge to cultivate the high-quality seedlings of M.glyptostroboides.In this study,a pot experiment in a greenhouse environment was carried out to identify the effect of N-exponential fertilization on the growth and nutrient distribution of M.glyptostroboides seedling.The M.glyptostroboides rooted seedlings with 12-month growth were chosen.Different N fertilizer levels with conventional fertilization(CF:5.0 g seedling^(−1)),exponential fertilization including EF1,EF2,EF3 and EF4 were determined.The relevant growth indexes were measured after 210-day growth.The results indicated that non-significant differences in seedlings’height and ground diameter were found among the above treatments(P>0.05);At the same time,N-exponential fertilization promoted the M.glyptostroboides’s biomass in different organs(P<0.05),with the maximum total biomass under EF3 treatment.The N accumulation in root and stem of the N-exponential fertilization treatments were increased in to some extent(P<0.05).The maximum N accumulation was also found under EF3 treatment.Therefore,steady-state nutrition and superior growth performance of M.glyptostroboides could be obtained by N-exponential fertilization of 5.0 g cutting^(−1).

Precise robust motion control of cell puncture mechanism driven by piezoelectric actuators with fractional-order nonsingular terminal slidingmode control

A novel robust controller is proposed in this study to realize the precise motion control of a cell puncture mechanism(CPM)driven by piezoelectric ceramics(PEAs).The entire dynamic model of CPM is constructed based on the Bouc–Wen model,and the nonlinear part of the dynamic model is optimized locally to facilitate the construction of a robust controller.A model-based,nonlinear robust controller is constructed using time-delay estimation(TDE)and fractional-order nonsingular terminal sliding mode(FONTSM).The proposed controller does not require prior knowledge of unknown disturbances due to its real-time online estimation and compensation of unknown terms by using the TDE technology.The controller also has finite-time convergence and high-precision trajectory tracking capabilities due to FONTSM manifold and fast terminal sliding mode-type reaching law.The stability of the closed-loop system is proved by Lyapunov stability theory.Computer simulation and hardware-in-loop simulation experiments of CPM verify that the proposed controller outperforms traditional terminal sliding mode controllers,such as the integer-order or model-free controller.The proposed controller can also continuously output without chattering and has high control accuracy.Zebrafish embryo is used as a verification target to complete the cell puncture experiment.From the engineering application perspective,the proposed control strategy can be effectively applied in a PEA-driven CPM.

Black phosphorus incorporated cobalt oxide:Biomimetic channels for electrocatalytic water oxidation

Learning from nature photosynthesis,the development of efficient artificial catalysts for water oxidation is an ongoing challenge.Herein,a lamellar cobalt oxide(CoO),black phosphorus(BP)and reduced graphene oxide(RGO)hybrid electrocatalyst is reported.BP domains are anchored on RGO and coated with CoO via P–O bonds.The widespread P–O bond network constitutes the proton acceptor and forms a proton exit channel,akin to the use of Asp61 in Photosystem II(PSII).The innermost kernel layer RGO serves as the current collector and forms an electron exit channel,mimicking the function of Tyr161 for charge transfer.The outermost encapsulation CoO layer acts as water oxidation catalyst(WOC).These biology‐inspired features endow an outstanding OER performance of the hybrid material with a low overpotential of 206 mV at a current density of 10 mA cm^(-2).This work provides a new design guide for OER electrocatalysts through constructing two specialized channels for proton and electron transfer.

A Double Adaptive Random Spare Reinforced Sine Cosine Algorithm

Many complex optimization problems in the real world can easily fall into local optimality and fail to find the optimal solution,so more new techniques and methods are needed to solve such challenges.Metaheuristic algorithms have received a lot of attention in recent years because of their efficient performance and simple structure.Sine Cosine Algorithm(SCA)is a recent Metaheuristic algorithm that is based on two trigonometric functions Sine&Cosine.However,like all other metaheuristic algorithms,SCA has a slow convergence and may fail in sub-optimal regions.In this study,an enhanced version of SCA named RDSCA is suggested that depends on two techniques:random spare/replacement and double adaptive weight.The first technique is employed in SCA to speed the convergence whereas the second method is used to enhance exploratory searching capabilities.To evaluate RDSCA,30 functions from CEC 2017 and 4 real-world engineering problems are used.Moreover,a nonparametric test called Wilcoxon signed-rank is carried out at 5%level to evaluate the significance of the obtained results between RDSCA and the other 5 variants of SCA.The results show that RDSCA has competitive results with other metaheuristics algorithms.

Highly crystalline core dominated the catalytic performance of carbon dot for cyclohexane to adipic acid reaction

Carbon dots(CDs)have uniquely structural,physicochemical and photochemical properties,suggesting a promising platform for catalysis applications.The in-depth understanding of the structure-activity relationship in the CDs-based catalyst system needs to know the effect of the crystalline core on their catalytic performance.The efficient catalytic oxidation of cyclohexane is an urgent challenge in current chemical industry,in which,adipic acid(AA)plays an important role in industry for synthesis of nylon6 and nylon-66.Here,we fabricated the pristine CDs by electrochemical etching graphite rod method and derived CDs with high crystalline core(CD-600,CD-800,and CD-1100)through a thermal treatment method in tube furnace.Furthermore,these CDs performed an outstanding catalytic performance for one-step synthesis of AA from cyclohexane.With the help of machine learning(ML),the deep correlations between features(structures of CDs,catalytic conditions)and catalytic performances were investigated by XGBoost(XGB)model.Then under the optimization and prediction of XGB,it was found that high crystalline core preceded the other features and CD-1100 could get the best conversion of 30.696%and selectivity to AA of 92.52%at reaction conditions of 130℃,1.5 MPa,and 10 h.This work pioneered the application of ML in industrial issues and demonstrated a comprehensive understanding on CDs as catalyst to realize one-step synthesis of AA.

Cation-πinteractions regulate electrocatalytic water oxidation over iridium single atoms supported on conjugated polymers

Designing cost-effective and high-performing metal catalysts is significant for many renewable energy conversion technologies.Lowering metal loading without sacrificing activity and durability is highly desired for the catalyst design,especially for those reactions where the noble metals deliver the best catalyzing performance.Single-atom catalysts(SACs)with maximal metalatom utilization,homogeneous and tailorable active sites have emerged as promising catalyst candidates,where the local coordination structures of the metal atoms in SACs largely determine the reaction kinetics.Previous design strategies of constructing strong metal-support interactions can stabilize the individual metal atoms in SACs,but present obstacles to provide a flexible manipulation platform for elaborately tailoring the coordination structures to achieve performance optimization towards a specifically targeted reaction.Here,for the proof-of-concept study,we report a novel design of SAC with iridium(Ir)single atoms supported on conjugated polymer,in which the adsorption energies of reaction intermediates on Ir atoms and the reaction kinetics towards acidic water oxidation can be readily optimized through modulating the formed cation-πinteractions that can be tailored by adjusting the molecular structures of conjugated polymers.This strategy establishes a general route to develop targeted SACs for various catalytic reactions.

藤仓赤霉菌赤霉素生物合成及代谢调控研究进展

赤霉素是最重要的植物生长调节剂之一,在农业生产中得到越来越广泛的应用,具有广阔的市场前景,但其工业化的高生产成本严重制约着它的广泛应用。近年来,利用生物技术提升赤霉素产量日益成为研究热点。赤霉素生物合成是多种酶协同作用的过程,阐明赤霉素的生物合成机制,利用代谢工程策略调控代谢流量,对提高赤霉素产量至关重要。文中综述了当前藤仓赤霉菌赤霉素生物合成途径、关键酶、环境因素、代谢流调控等方面的研究进展,在代谢调控方面进行了展望,以期为实现赤霉素稳产高产提供思路。

A stepwise-designed Rh-Au-Si nanocomposite that surpasses Pt/C hydrogen evolution activity at high overpotentials

Hydrogen evolution by electrocatalysis clean energy. However, it is challenging is an attractive method of supplying to find cheap and efficient alternatives to rare and expensive platinum based catalysts. Pt provides the best hydrogen evolution performance, because it optimally balances the free energies of adsorption and desorption. Appropriate control of these quantities is essential for producing an efficient electrocatalyst. We demonstrate, based on first principles calculations, a stepwise designed Rh-Au-Si ternary catalyst, in which adsorption （the Volmer reaction） and desorption （the Heyrovsky reaction） take place on Rh and Si surfaces, respectively. The intermediate Au surface plays a vital role by promoting hydrogen diffusion from the Rh to the Si surface. Theoretical predictions have been explored extensively and verified by experimental observations. The optimized catalyst （Rh-Au-SiNW-2） has a com- position of 2.2：28.5：69.3 （Rh：Au：Si mass ratio） and exhibits a Tafel slope of 24.0 mV.dec-L Its electrocatalytic activity surpasses that of a commercial 40 wt.% Pt/C catalyst at overpotentials above 0.19 V by exhibiting a current density of greater than 108 mA-cm-2. At 0.3 V overpotential, the turnover frequency of Rh-Au-SiNW-2 is 10.8 times greater than that of 40 wt.% Pt/C. These properties may open new directions in the stepwise design of highly efficient catalysts for the hydrogen evolution reaction （HER）.

An improved YOLOv3-tiny algorithm for vehicle detection in natural scenes

YOLO(You Only Look Once),as a target detection algorithm with good speed and precision,is widely used in the industry.In the process of driving,the vehicle image captured by the driving camera is detected and it extracts the license plate and the front part of the vehicle.Compared with the network structure of YOLOv3-tiny algorithm,the acquisition method of anchor box is improved by combining the Birch algorithm.In order to improve the real-time performance,the original two-scale detection is added to the multi-scale prediction of three-scale detection to ensure its accuracy.Finally,the experimental results show that the improved YOLOv3-tiny network structure proposed in this study can improve the performance of mean-average-precision,intersection over union and speed by 5.99%,17.52%and 48.4%,respectively,and the algorithm has certain robustness.

Surface Engineered Ru_(2)Ni Multilayer Nanosheets for Hydrogen Oxidation Catalysis

The hydrogen oxidation reaction(HOR)in alkaline conditions is of great importance for the application of anion exchange membrane fuel cells(AEMFCs).However,the electrocatalysts for alkaline HOR generally suffer from the disadvantage of sluggish kinetics.Herein,we have fabricated Ru2Ni multilayered nanosheets(Ru2Ni MLNSs)in the layer-by-layer manner and engineered the surface properties via postannealing for efficient alkaline HOR.Detailed investigations reveal that such annealing at different temperatures can alter the surface properties of Ru2Ni MLNSs and thus regulate their adsorption abilities toward*H and*OH.In particular,the optimal catalyst exhibits a mass activity of 4.34 A mgRu−1 at an overpotential of 50 mV,which is 18.1 and 13.2 times higher than those of Ru/C(0.24 A mgRu−1)and Pt/C(0.33 A mgPt−1),respectively.Theoretical calculations indicate that the presence of surface O atoms can facilitate the HOR activity while the excessive coverage of O atoms on Ru2Ni surface leads to the strengthened H binding and the decay of HOR activity.This work not only provides an efficient catalyst for alkaline HOR,but it also may shed new light on the design of high-performance catalysts for electrocatalysis and beyond.We have fabricated Ru2Ni multilayer nanosheets(Ru2Ni MLNSs)and realized the surface engineering via an annealing process.Detailed investigations show that such surface engineering can regulate the surface properties and thus promote the alkaline HOR activity.Consequently,the optimal catalyst exhibits a much higher activity than those of commercial Ru/C and Pt/C and is a promising catalyst for alkaline HOR.

Ag@Pt等离激元复合纳米结构中热电子级联传输增强电催化反应

将具有高催化活性的材料与等离激元金属纳米材料复合是制备局域表面等离激元共振增强电催化剂的常用策略.然而,这种复合方式不仅会降低等离激元材料的局域表面等离激元共振强度,同时会改变等离激元电磁场的逸散方式以及热电子在复合结构内部的传输途径,无法实现最佳的等离激元增强效果.在此,我们选择了简单的Ag@Pt双金属纳米立方体作为研究对象,深入探究了热电子在金属异质结构内部的激发和传输机制以及其在电化学析氢反应中的贡献.相应的实验和理论结果证实,Pt在Ag表面的复合会改变等离激元电磁场的逸散方式,促进激发产生更多热电子,同时热电子可以通过级联传输方式转移至复合结构表面,显著增强电催化反应.这项工作为等离激元金属异质结构催化剂的设计和应用提供了重要参考.

Growth,coalescence,and etching of two-dimensional overlayers on metals modulated by near-surface Ar nanobubbles

The synthesis of high-quality ultrathin overlayers is critically dependent on the surface structure of substrates,especially involving the overlayer–substrate interaction.By using in situ surface measurements,we demonstrate that the overlayer–substrate interaction can be tuned by doping near-surface Ar nanobubbles.The interfacial coupling strength significantly decreases with near-surface Ar nanobubbles,accompanying by an“anisotropic to isotropic”growth transformation.On the substrate containing near-surface Ar,the growth front crosses entire surface atomic steps in both uphill and downhill directions with no difference,and thus,the morphology of the two-dimensional(2D)overlayer exhibits a round-shape.Especially,the round-shaped 2D overlayers coalesce seamlessly with a growth acceleration in the approaching direction,which is barely observed in the synthesis of 2D materials.This can be attributed to the immigration lifetime and diffusion rate of growth species,which depends on the overlayer–substrate interaction and the surface catalysis.Furthermore,the“round to hexagon”morphological transition is achieved by etching-regrowth,revealing the inherent growth kinetics under quasi-freestanding conditions.These findings provide a novel promising way to modulate the growth,coalescence,and etching dynamics of 2D materials on solid surfaces by adjusting the strength of overlayer–substrate interaction,which contributes to optimization of large-scale production of 2D material crystals.

A mechanistic study of selective propane dehydrogenations on MoS_(2) supported single Fe atoms

On-purpose propane dehydrogenation(PDH) has emerged as a profitable alternative to the traditional cracking of oil products for propylene production. By means of density functional theory(DFT) calculations, the present work demonstrates that Fe atoms may atomically disperse on MoS_(2)(Fe_(1)/MoS_(2)) and serve as a promising single-atom catalyst(SAC) for PDH. The catalytic activity of Fe_(1)/MoS_(2)is attributed to the highly exposed d orbitals of single Fe atoms, while the propylene selectivity is originated from the kinetic inhibition of propylene dehydrogenation resulting from fast propenyl hydrogenation. The unique catalytic selectivity of Fe_(1)/MoS_(2)may inspire further investigations of on-purpose dehydrogenations of propane on SACs.

The triggering of catalysis via structural engineering at atomic level: Direct propane dehydrogenation on Fe-N_(3)P-C

The on-purpose direct propane dehydrogenation(PDH) has received extensive attention to meet the everincreasing demand of propylene.In this work,by means of density functional theory(DFT) calculations,we systematically studied the intrinsic coordinating effect of Fe single-atom catalysts in PDH.Interestingly,the N and P dual-coordinated single Fe(Fe-N_(3)P-C) significantly outperform the Fe-N_(4-)C site in catalysis and exhibit desired activity and selectivity at industrial PDH temperatures.The mechanistic origin of different performance on Fe-N_(3)P-C and Fe-N_(4-)C has been ascribed to the geometric effect.To be specific,the in-plane configuration of Fe-N_(4) site exhibits low H affinity,which results in poor activity in C-H bond activations.By contrast,the out-of-plane structure of Fe-N_(3)P-C site exhibits moderate H affinity,which not only promote the C-H bond scission but also offer a platform for obtaining appropriate H diffusion rate which ensures the high selectivity of propylene and the regeneration of catalysts.This work demonstrates promising applications of dual-coordinated single-atom catalysts for highly selective propane dehydrogenation.

Boosting electrocatalytic selectivity in carbon dioxide reduction:The fundamental role of dispersing gold nanoparticles on silicon nanowires

Carbon dioxide electrochemical reduction(CO_(2)RR)has been recognized as an efficient way to mitigate CO_(2)emissions and alleviate the pressure on global warming and associated environmental consequences.Gold(Au)is reported as stable and active electrocatalysts to convert CO_(2)to CO at low overpotential due to its moderate adsorption strength of^(*)COOH and^(*)CO.The request for improved catalytic performance,however,is motivated by current unsatisfied catalytic selectivity because of the side hydrogen evolution reaction.In this context,the design of Au based binary catalysts that can boost CO selectivity is of great interest.In the present work,we report that Au nanoparticles can be feasibly dispersed and anchored on silicon nanowires to form Au-Si binary nanomaterials.The Au-Si may stably drive CO_(2)RR with a CO Faraday efficiency of 95.6%at−0.6 V vs.RHE in 0.5 mol/L KHCO_(3)solution.Such selectivity outperforms Au particles by up to 61%.Controlled experiments illustrate that such catalytic enhancement can chiefly be ascribed to electronic effects of binary catalysts.Theoretical calculations reveal that spontaneously produced silicon oxide may not only inhibit hydrogen evolution reaction,but also stabilize the key intermediate^(*)COOH in CO formation.

Preface to Inorganic Catalysts

Exploring and developing renewable energy conversion devices has become one of the efficient solutions for energy crises and environmental problems.Electro-and photo-catalysis is recognized as a practical process for chemical energy conversion,which has attracted considerable research efforts in the design and development of high-performing electrocatalysts in recent decades.The development of new methods to prepare inorganic heterogeneous materials has extended the limits of functional material synthesis for the diverse fields of electro-and photo-catalysis.This special issue will review and present the latest developments in inorganic heterogeneous catalysts for electro-and photo-catalysis.We believe that this special issue will contribute to the rational design and synthesis of inorganic heterogeneous catalysts,the applications in various reactions,and the in-depth understanding of the relationship between structure and activity.