Preliminary Study on Forest Fire Prevention and Extinguishing in Townships in the Southern Mountainous Areas of Zhejiang Province:A Case Study of Lishui

Forest fires seriously threaten forestry resources and the life and property safety of people in mountainous areas of Lishui City. In this paper, a fire prevention concept with refined forecast and early warning of forest fire danger weather ratings in townships as the starting point, satellite real-time observation of fire spots, monitoring of the Internet of Things and other high-tech products as an implementation means, and strengthening forest fire prevention equipment and personnel in townships as a guarantee was established. The command system for rapid emergency response by cities, counties and townships should be improved. During the forest fire prevention period, fire sources should be strictly controlled, and the basic principles of forest fire fighting in townships should be implemented into the actual fire prevention and fire fighting work to eliminate forest fires in time at the initial stage and before the disaster.

Research on the longitudinal protection of a through-type cophase traction direct power supply system based on the empirical wavelet transform

This paper proposes a longitudinal protection scheme utilizing empirical wavelet transform(EWT)for a through-type cophase traction direct power supply system,where both sides of a traction network line exhibit a distinctive boundary structure.This approach capitalizes on the boundary’s capacity to attenuate the high-frequency component of fault signals,resulting in a variation in the high-frequency transient energy ratio when faults occur inside or outside the line.During internal line faults,the high-frequency transient energy at the checkpoints located at both ends surpasses that of its neighboring lines.Conversely,for faults external to the line,the energy is lower compared to adjacent lines.EWT is employed to decompose the collected fault current signals,allowing access to the high-frequency transient energy.The longitudinal protection for the traction network line is established based on disparities between both ends of the traction network line and the high-frequency transient energy on either side of the boundary.Moreover,simulation verification through experimental results demonstrates the effectiveness of the proposed protection scheme across various initial fault angles,distances to faults,and fault transition resistances.

Continuous, homogeneous and rapid synthesis of 4-bromo-3-methylanisole in a modular microreaction system

4-Bromo-3-methylanisole is mainly used to synthesize black fluorane dye(2-anilino-3-methyl-6-dibutylaminofluorane, ODB-2), which is one of the most important heat and pressure-sensitive dyes in the manufacture of thermal papers. Compared to the industrial heterogeneous batch process, a continuous homogeneous bromination technology in a modular microreaction system has been developed, and 4-bromo-3-methylanisole has been successfully prepared through high-selective mono-bromination of 3-methylanisole with Br2 solution in CHCl3. In optimal conditions, the content of bis-brominated byproducts can be controlled less than 0.5%,which is superior to the industrial standard with 99.5% 3-methylanisole conversion at very short residence time and mild reaction temperature.

Reaction kinetics determination based on microfluidic technology

Microfluidic technology has been successfully applied to determine the reaction kinetics relying on its great characteristics including narrow residence time distribution,fast mixing,high mass and heat transfer rates and very low consumption of materials.In this review,the recent progresses about the reaction kinetics measured in microreactors are comprehensively organized,and the kinetic modeling thoughts,determination methods and essential kinetic regularities contained in these studies are summarized according to the reaction types involving nitration,oxidation,hydrogenation,photochemical reaction,polymerization and other reactions.Besides,the significant advances in the innovation of microplatform are also covered.The novel reactor configuration methods were established mainly to achieve rapid and efficient data collection and analysis.Finally,the advantages of microfluidic technology for the kinetic measurement are summarized,and a perspective for the future development is provided.

Ideality analysis and general laws of bubble swarm microflow for large-scale gas-liquid microreaction processes

The flow ideality of bubbly microflow remains unclear even though it is vital for the design of microreactors,especially the ideality of bubble swarm microflow for large-scale gas-liquid microreaction processes.This work is the first time to report the ideality analysis of the microbubble swarm in a relatively large microchannel.The bubble swarm microflow has undergone two conditions:quasihomogeneous plug flow and liquid phase/gas-liquid qua si-homogeneous phase two-phase laminar flow.Both the deviations of void fraction and bubble velocity from the ideal plug flow can divide into two parts,and the two transition points simultaneously happen at the velocity ratio of 1.25.There exists a critical capillary number to maintain the quasi-homogeneous plug flow,which could be regarded as the general laws for the design of gas-liquid microreactors.Finally,a novel model is developed to predict the bubble velocity.This work could be very helpful for the large-scale gas-liquid microreactors design.

Determination of interfacial tension and viscosity under dripping flow in a step T-junction microdevice

Microfluidic approaches for the determination of interfacial tension and viscosity of liquid-liquid systems still face some challenges.One of them is liquid-liquid systems with low interfacial and high viscosity,because dripping flow in normal microdevices can’t be easily realized for the systems.In this work,we designed a capillary embedded step T-junction microdevice to develop a modified microfluidic approach to determine the interfacial tension of several systems,specially,for the systems with low interfacial tension and high viscosity.This method combines a classical T-junction geometry with a step to strengthen the shear force further to form monodispersed water/oil(w/o)or aqueous two-phase(ATP)droplet under dripping flow.For systems with low interfacial tension and high viscosity,the operating range for dripping flow is relative narrow whereas a wider dripping flow operating range can be realized in this step Tjunction microdevice when the capillary number of the continuous phase is in the range of 0.01 to 0.7.Additionally,the viscosity of the continuous phase was also measured in the same microdevice.Several different systems with an interfacial tension from 1.0 to 8.0 m N·m^(-1) and a viscosity from 0.9 to 10 m Pa·s were measured accurately.The experimental results are in good agreement with the data obtained from a commercial interfacial tensiometer and a spinning digital viscometer.This work could extend the application of microfluidic flows.

New indications of gas hydrate in the northeastern China permafrost zone

1.Objectives The Mohe Basin in Heilongjiang,China has a NEE thrust nappe belt,which was assembled by the root zone,middle thrust zone and thrust front,north-south and north-east normal faults with three tectonic activities of the Middle Jurassic to. Eocene,the Miocene,and the Early to Middle Pleistocene. The middle thrust zone and thrust front has a large number of folds,thrust faults,fractures and glutenites,which are the major structures of gas hydrate accumulation in the Mohe Basin.

Analysis of Steel Connections to Resist Progressive Collapse

This paper presented a methodology for the analysis and design of steel connections under a double-span connection within the context of preventing progressive collapse. First, various connection models were described and their pros and cons were provided. Then, the load-displacement characteristics of a component-based spring model were described. Thirdly, an experi-mental study on the behaviors of shear tab connections under tension was presented. The main sources of the deformation capacity of the shear tab connections were identified. Finally, a design example of a shear tab connection was provided to illustrate the methodology.

Clinical observation on the treatment of severe hand-foot-mouth disease with antelope horn powder combined with auricular point application

Objective:To explore the Clinical observation on the treatment of severe hand-foot-mouth disease with antelope horn powder combined with auricular point application.Methods:From July 2016 to June 2018,90 children were randomly divided into control group(n=30),treatment group(n=30)and control group(n=30).The control group was treated with routine western medicine,the treatment group 1 was treated with oral antelope horn powder on the basis of control group,the second group was treated with auricular point application on the basis of treatment group 1,and the time of symptom relief and clinical cure were observed in each group.Related immune function and related inflammatory factors,serum neuron-specific enolase(NSE),safety index.Results:In treatment group 1,the time of herpes regression,antipyretic,antispasmodic time and clinical cure time were shorter than those of control group,and the time of treatment 2 group was shorter than that of group 1(P<0.05).The levels of CD3,CD4 and CD8 were increased after treatment in the three groups,especially in the treatment group(P<0.05),and the levels of TNF-毩αand IL-2,IL-6,IL-10 were decreased after treatment in the three groups,especially in the treatment group(P<0.05).NSE decreased after treatment in three groups,especially in treatment group 2(P<0.05).Conclusion:The application of antelope horn powder combined with auricular point application can obviously improve the severe hand,foot and mouth disease,and the clinical curative effect is definite.It is worth popularizing and applying in clinical practice.

Organic single-crystal light-emitting transistors with external quantum efficiency over 20%

Organic light-emitting transistors(OLETs)have attracted increasing attention because of their potential applications in next-generation displays and high-energy operating devices.However,the simultaneous achievement of high luminescent efficiency and carrier mobility in organic semiconductors remains challenging because the localized excitons are advantageous for light emission,whereas the delocalized carriers are beneficial for efficient charge migration.Herein,we report an organic single crystal of a cyano-substituted styrene derivative with balanced mobility yielding a record-high external quantum efficiency of 20.5%in OLETs.Temperature-dependent I–V curves and electronic structure analyses based on firstprinciples calculations were performed to disclose the underlying mechanism as a band transport,which provides an efficient way to achieve high quantum efficiency in OLETs.

Unsteady simulation for a high-speed train entering a tunnel

In order to study the unsteady aerodynamics effects in railway tunnels,the 3D Reynolds average Navier-Stokes equations of a viscous compressible fluid are solved,and the two-equation k-ε model is used in the simulation of turbulence,while the dynamic grid technique is employed for moving bodies.We focus on obtaining the changing tendencies of the aerodynamic force of the train and the aerodynamic pressures on the tunnel wall and train surface,and discovering the relationship between the velocity of the train and the intensity of the micro pressure wave at the tunnel exit.It is shown that the amplitudes of the pressure changes in the tunnel and on the train surface are both approximately proportional to the square of the train speed,so are the microwave and the drag of the train.

Microreaction Technology for Synthetic Chemistry

Microreaction technology as an emerging tool for synthetic chemistry has been extensively applied in academic and industrial researches. Normally, synthetic chemists used to running reactions in the classical glassware for cen turies are unfamiliar and unaccustomed to use microreaction tech no logy for routine synthetic work. This review tries to give a general introduction of the capabilities of microreaction tech no logy.

Experimental and numerical studies on the cavitation over flat hydrofoils with and without obstacle

To control the shedding of cavitation, an obstacle is placed on the surface of a flat hydrofoil. Both experimental and numerical studies are carried out. Images of cavitation evolution are recorded by a high-speed camera. 3-D simulations are performed to investigate the cavitating flows around the hydrofoil. The results show that the re-entrant jet plays an important role during the process of cavitation shedding. A kind of U-type shedding is identified during the evolution of the cloud cavitation. The length of the cavity is apparently reduced due to the placement of the obstacle. It is interesting to find that the cavitation shedding changes from the large-scale mode to a small-scale mode, as an obstacle is placed on the hydrofoil surface. As we can observe from both experimental and numerical results, the small-scale cavitation shedding dominates the cavitating flow dynamics, we thereby conclude that the placement of an obstacle is favorable for the inhibition of cavitation shedding.

Parameter effects on high-speed UAV ground directional stability using bifurcation analysis

A loss of ground directional stability can trigger a high-speed Unmanned Aerial Vehicle(UAV)to veer off the runway.In order to investigate the combined effects of the key structural and operational parameters on the UAV ground directional stability from a global perspective,a fully parameterized mathematical high-speed UAV ground nonlinear dynamic model is developed considering several nonlinear factors.The bifurcation analysis procedure of a UAV ground steering system is introduced,following which the simulation efficiency is greatly improved comparing with the time-domain simulation method.Then the numerical continuation method is employed to investigate the influence of the nose wheel steering angle and the global stability region is obtained.The bifurcation parameter plane is divided into several parts with different stability properties by the saddle nodes and the Hopf bifurcation points.We find that the UAV motion states will never cross the bifurcation curve in the nonlinear system.Also,the dual-parameter bifurcation analyses are presented to give a complete description of the possible steering performance.It is also found that BT bifurcation appears when the UAV initial rectilinear velocity and the tire frictional coefficient vary.In addition,results indicate that the influence of tire frictional coefficient has an opposite trend to the influence of initial rectilinear velocity.Overall,using bifurcation analysis method to identify the parameter regions of a UAV nonlinear ground dynamic system helps to improve the development efficiency and quality during UAV designing phase.

Comparing Competition Equilibrium with Nash Equilibrium in Electric Power Market

The Nash equilibrium and competition equilibrium have been widely studied in the electric power market up to now.In this paper,it is explained that the Nash equilibrium can be achieved by using marginal cost pricing and the com-petition equilibrium can be performed by using accounting cost pricing based on the model of the power market system.The comparison between the Nash equilibrium and competition equilibrium indicates that surplus and unfair allocation of market benefits may be obtained by the Nash equilibrium,and the competition equilibrium realizes the optimization in economics with maximum market efficiency and fairness for market benefit allocations while the optimization in mathematics is achieved by the Nash equilibrium.There is sameness between the Nash equilibrium and competition equilibrium at the point when the power network characteristics are disregarded.The case study is made on a IEEE 30-bus system,and the calculation results indicate that it is the key issue to perform the competition equilibrium by using accounting cost pricing.

COVID-19胃肠道感染和SARS-CoV-2潜在的粪便传播

多中心临床数据显示,部分2019冠状病毒病(COVID-19)患者存在腹泻、恶心和呕吐等胃肠道症状,相关研究也证实严重急性呼吸综合征冠状病毒2型(SARS-Co V-2)能够在胃肠道复制并从粪便中分离到活的SARS-Co V-2。在意大利和澳大利亚等国,其未处理的污水中检测到了SARS-Co V-2,且根据污水中SARS-Co V-2的含量估算出的COVID-19患者与临床实际感染患者较为一致。粪便中的SARS-Co V-2能够挥发存在于气溶胶中并保持较长时间的活力,故当人们暴露在被SARS-Co V-2污染的环境中即可能经"粪便-气溶胶-粘膜"途径感染SARS-Co V-2,而当人们食用被SARS-Co V-2污染的食物或水则可能经"粪-口"途径感染SARS-Co V-2。因此,对可能被COVID-19患者粪便污染的环境或物品进行严格管理和有效消毒对控制COVID-19大流行具有重要意义。

Active flow control with rotating cylinders by an artificial neural network trained by deep reinforcement learning

In this paper,an artificial neural network(ANN)trained through a deep reinforcement learning(DRL)agent is used to perform flow control.The target is to look for the wake stabilization mechanism in an active way.The flow past a 2-D cylinder with a Reynolds number 240 is addressed with and without a control strategy.The control strategy is based on using two small rotating cylinders which are located at two symmetrical positions back of the main cylinder.The rotating speed of the counter-rotating small cylinder pair is determined by the ANN and DRL approach.By performing the final test,the interaction of the counter-rotating small cylinder pair with the wake of the main cylinder is able to stabilize the periodic shedding of the main cylinder wake.This demonstrates that the way of establishing this control strategy is reliable and viable.In another way,the internal interaction mechanism in this control method can be explored by the ANN and DRL approach.

Study on modal characteristics and vibration reduction of an aircraft rotor–stator brake-induced squeal system

Based on the modal coupling theory,the rotor and stator contact stiffness and axial relative velocity are considered to build an electric aircraft brake dynamic system model in this study.Both the complex modal analysis and transient dynamic analysis methods are used to study the aircraft brake squeal performance and vibratory mechanism.The unstable vibration modes indicate that the out-of-plane vibration plays an important role and the feed-in energy is larger than the output energy in the brake rotor–stator module so that brake squeal takes place.Then the influences of the contact stiffness,friction damping and frictional coefficient on the brake squeal system are carried out,laying the foundation for the three proposed vibration suppression methods.Results show that the coefficient negative-slope condition will intensify the vibration.Also,a linear relationship between the squeal factor and the frictional coefficient is obtained to provide a guidance to predict squeal stability under more conditions.Vibration reduction design shows that adding a damping layer to the brake mechanism and chamfering the edge of braking stators both can reduce brake squeal effectively,while slotting braking stators is invalid in aircraft braking system.

SARS-CoV-2 NSP5 and N protein counteract the RIG-I signaling pathway by suppressing the formation of stress granules

As a highly pathogenic human coronavirus,SARS-CoV-2 has to counteract an intricate network of antiviral host responses to establish infection and spread.The nucleic acid-induced stress response is an essential component of antiviral defense and is closely related to antiviral innate immunity.However,whether SARS-CoV-2 regulates the stress response pathway to achieve immune evasion remains elusive.In this study,SARS-CoV-2 NSP5 and N protein were found to attenuate antiviral stress granule(avSG)formation.Moreover,NSP5 and N suppressed IFN expression induced by infection of Sendai virus or transfection of a synthetic mimic of dsRNA,poly(I:C),inhibiting TBK1 and IRF3 phosphorylation,and restraining the nuclear translocalization of IRF3.Furthermore,HEK293T cells with ectopic expression of NSP5 or N protein were less resistant to vesicular stomatitis virus infection.Mechanistically,NSP5 suppressed avSG formation and disrupted RIG-I–MAVS complex to attenuate the RIG-I–mediated antiviral immunity.In contrast to the multiple targets of NSP5,the N protein specifically targeted cofactors upstream of RIG-I.The N protein interacted with G3BP1 to prevent avSG formation and to keep the cofactors G3BP1 and PACT from activating RIG-I.Additionally,the N protein also affected the recognition of dsRNA by RIG-I.This study revealed the intimate correlation between SARS-CoV-2,the stress response,and innate antiviral immunity,shedding light on the pathogenic mechanism of COVID-19.

Mineralization of phenol by ozone combined with activated carbon:Performance and mechanism under different pH levels

The degradation of phenol using ozone with activated carbon(O_(3)/AC system)was investigated in this study.The O_(3)/AC system was also compared with the single O_(3) and AC systems.The total organic carbon(TOC)removal efficiency in the O_(3)/AC system was roughly 26%and 30%higher than the single AC and O_(3) systems,respectively.It was demonstrated that the phenol degradation rate and TOC removal efficiency were significantly affected by the ozone concentration,AC dosage,and solution pH.The pseudo-first-order and pseudo-second-order kinetic models were fitted to identify the mechanisms of the phenol removal process.The results of Scanning Electron Microscopy,Brunauer-Emmett-Teller,and Fourier-transform infrared spectroscopy of raw and used AC indicated that the surface morphology,microstructure,and functional group properties had been changed during the reaction process.The possible O_(3)/AC system mineralization mechanism for phenol removal was tentatively proposed using scavenging active species such as·OH,O_(2)^(·-),and H_(2)O_(2).The transformation byproducts generated during the application of the O_(3)/AC system were identified by High Performance Liquid Chromatography and Gas Chromatography-Mass Spectrometry analyses.Therefore,the mineralization pathway of phenol in detail was proposed in acidic(pH 3.0)and alkaline(pH 11.0)conditions.This study provided a more systematic explanation of the mineralization mechanism for phenol in the O_(3)/AC system.