Research on Landscape Design of Waterfront Public Space in Mountainous Cities Based on User Experience-Taking the Waterfront Landscape Design of Art Peninsula in Chongqing as an Example

Mountainous cities are dominated by mountainous,hilly,and steep terrain,which brings certain complexity and particularity to the planning and construction of waterfront spaces in these cities compared to plain cities.Waterfront spaces,often serving as the core areas of city development,possess favorable location advantages and special attributes of water-land intersection,giving them more possibilities for functional transformation[1].However,the ultimate goal of design is to provide users with a vibrant waterfront area.The design of waterfront spaces should focus more on people’s behavioral needs,allowing users to feel a good interaction between the place and their behavioral needs during space usage[2].Therefore,the design incorporates human environmental behavior,increases interactive experiences,and enriches spatial interest.

Research on the Construction of a Comprehensive Teaching Case Library for Ergonomics under the OBE Concept

In recent years,case-based teaching has become a hot spot in higher education reform,and the construction of case libraries has received increasing attention.The development of teaching case libraries not only promotes changes in talent training models but also enhances teaching effectiveness.Taking the ergonomics course as an example,this paper explores the construction of a comprehensive teaching case library for ergonomics under the outcome-based education concept,providing a reference for future ergonomics teaching case library development.

Analysis of the Role of Nursing Intervention in Operating Room in the Prevention of Incision Infection in Orthopedic Aseptic Surgery

Objective:To explore and analyze the role of nursing in the operating room in the prevention of incision infection in aseptic orthopedic surgery.Methods:68 patients that underwent aseptic orthopedic surgery in our hospital from January 2021 to December 2022.They were divided into a research group(n=34)and a control group(n=34)by the random number table method.The patients in the control group received conventional nursing intervention in the operating room,and the patients in the study group received the optimized and modified nursing intervention in the operating room;then,the related indicators of nursing intervention of the two groups were compared.Results:The incidence of incision infection in the study group was lower than that of the control group(P<0.05);the average duration of surgery and length of stay the study group were lower than those in the control group(P<0.05);the stress response indexes of patients in the study group were lower than those in the control group 24 hours after operation(P<0.05);the degree of satisfaction of the patients in the study group to the services provided by the nursing staff was significantly higher than that of the control group(P<0.05).Conclusion:High-quality nursing intervention in the operating room for aseptic orthopedic surgery patients can significantly reduce the incidence of incision infection,reduce the stress response caused by surgery,shorten the duration of surgery and length of stay,and improve nursing satisfaction,which makes it worthy of popularization.

The Role of KDM2A and H3K36me2 Demethylation in Modulating MAPK Signaling During Neurodevelopment

Intellectual disability(ID)is a condition characterized by cognitive impairment and difficulties in adaptive functioning.In our research,we identified two de novo mutations(c.955C>T and c.732C>A)at the KDM2A locus in individuals with varying degrees of ID.In addition,by using the Gene4Denovo database,we discovered five additional cases of de novo mutations in KDM2A.The mutations we identified significantly decreased the expression of the KDM2A protein.To investigate the role of KDM2A in neural development,we used both 2D neural stem cell models and 3D cerebral organoids.Our findings demonstrated that the reduced expression of KDM2A impairs the proliferation of neural progenitor cells(NPCs),increases apoptosis,induces premature neuronal differentiation,and affects synapse maturation.Through ChIP-Seq analysis,we found that KDM2A exhibited binding to the transcription start site regions of genes involved in neurogenesis.In addition,the knockdown of KDM2A hindered H3K36me2 binding to the downstream regulatory elements of genes.By integrating ChIP-Seq and RNA-Seq data,we made a significant discovery of the core genes'remarkable enrichment in the MAPK signaling pathway.Importantly,this enrichment was specifically linked to the p38 MAPK pathway.Furthermore,disease enrichment analysis linked the differentially-expressed genes identified from RNA-Seq of NPCs and cerebral organoids to neurodevelopmental disorders such as ID,autism spectrum disorder,and schizophrenia.Overall,our findings suggest that KDM2A plays a crucial role in regulating the H3K36me2 modification of downstream genes,thereby modulating the MAPK signaling pathway and potentially impacting early brain development.

二氧化钼纳米棒的制备及电化学性能研究

MoO_(2)纳米棒具有高电导率、高熔点及比容量较大,在超级电容器电极材料领域应用前景广泛。现有MoO_(2)纳米棒制备方法大多存在操作复杂、收率低、成本高、易引入杂质等问题,且这些方法制备的MoO_(2)产品存在形貌不均一、分散性差、电化学性能低的问题。基于此,本工作以双氧水和钼粉制备的过氧钼酸前驱体为钼源,PEG(8000)为模板剂制备出带状结构含钼杂化物,然后以浆态带状杂化物为原料采用两段式全湿法工艺制备纳米棒状MoO_(2)。利用X射线衍射(XRD)、X射线光电子能谱(XPS)、X射线能谱(EDS)和扫描电子显微镜(SEM)等对二氧化钼纳米棒的物相、表面组成与形貌进行了分析,同时分别采用三电极和两电极体系研究了MoO_(2)纳米棒的电化学电容行为,考察了MoO_(2)纳米棒直接作为电极组装电容的性能。结果表明,所制的MoO_(2)为长约500~800 nm、宽约100~200 nm的棒状结构,形貌与尺寸均匀,具有良好的分散性和较高的纯度。以MoO_(2)纳米棒制备的电极在1 A/g的电流密度下,三电极和两电极体系所测得比电容分别为366.7和290.4 F/g;在5 A/g电流密度下循环充放电2000次后电容保持率均高于72%,展现出了良好的电化学性能。该研究结果可为纳米金属氧化物的制备提供新方法。

Overview of Mechanism and Mitigation Measures on Multi-frequency Oscillation Caused by Large-scale Integration of Wind Power

In recent years,the large-scale integration of re-newable energy sources represented by wind power and the widespread application of power electronic devices in power systems have led to the emergence of multi-frequency oscillation problems covering multiple frequency segments,which seriously threaten system stability and restrict the accommodation of renewable energy.The oscillation problems related to renewable energy integration have become one of the most popular topics in the field of wind power integration and power system stability research.It has received extensive attention from both academia and industries with many promising research results achieved to date.This paper first analyzes several typical multi-frequency oscillation events caused by large-scale wind power integration in domestic and foreign projects,then studies the multi-frequency oscillation problems,including wind turbine’s shafting torsional oscillation,sub/super-synchronous oscillation and high frequency resonance.The state of the art is systematically summarized from the aspects of oscillation mechanism,analysis methods and mitigation measures,and the future research directions are explored.

Coordinated Damping Optimization Control of Sub-synchronous Oscillation for DFIG and SVG

Currently, the power electronics-based devices, includinglarge-scale non-synchronized generators and reactivepower compensators, are widely used in power grids. This helpsintroduce the coupling interactions between the devices andthe power grid, resulting in a new sub-synchronous oscillationphenomenon. It is a critical element for the stability operation ofthe power grid and its devices. In this paper, the sub-synchronousoscillation phenomenon of the power grid connected with largescalewind power generation is analyzed in detail. Then, inorder to damp the sub-synchronous oscillation, a coordinateddamping optimization control strategy for wind power generatorsand their reactive power compensators is proposed. The proposedcoordinated control strategy tracks the sub-synchronousoscillation current signal to correct the corresponding controlsignal, which increases the damping of power electronics. Theresponse characteristics of the proposed control strategy areanalyzed, and a self-optimization parameter tuning method basedon sensitivity analysis is proposed. The simulation results validatethe effectiveness and the availability of the proposed controlstrategy.

Fault Ride Through Strategy of DFIG Using Rotor Voltage Direct Compensation Control Under Voltage Phase Angle Jump

Wind power has developed rapidly in recent years,and large-scale wind power facilities connected to power grids will bring many new challenges.Some new operation charac-teristics of power grids with doubly-fed induction generator(DFIG)may exhibit,for example voltage phase angle jumps(VPAJ).VPAJ can negatively impact the fault ride through(FRT)performance of DFIG.This paper firstly investigates the physical mechanism and the operation characteristics of DFIG with VPAJ.It is noted that the current control strategies designed for voltage amplitude changes are not suitable for VPAJ.Secondly,the paper develops an FRT optimization control strategy under VPAJ which optimizes the DFIG operation characteristics.Finally,simulations of a 250 MW wind farm are presented which validate the proposed FRT strategy.

Voltage phase angle jump characteristic of DFIGs in case of weak grid connection and grid fault

In the condition of connecting large scale doubly-fed induction generators (DFIGs) into weak grid,the closely coupled interactions between wind generators and power grid becomes more severe.Some new fault characteristics including voltage phase angle jump will emerge,which will influence the power quality of power system.However,there are very few studies focusing on the mechanism of voltage phase angle jump under grid fault in a weak grid with wind turbine integration.This paper focuses on the scientific issues and carries out mechanism studies from different aspects,including mathematical deduction,field data analysis and time domain simulation.Based on the analysis of transientcharacteristics of DFIGs during the grid fault,this paper points out that the change of terminal voltage phase angle in DFIGs is an electromagnetism transition process,which is different from conventional synchronous generator.Moreover,the impact on transient characteristics of voltage phase angle are revealed in terms of fault ride through(FRT) control strategies,control parameters of current inner-loop of rotor-side converter and grid strength.

Transient characteristics and adaptive fault ride through control strategy of DFIGs considering voltage phase angle jump

Wind power in China has experienced fast development in recent years. However, areas rich in wind power resources are often far away from loads centers,which leads to weak connection between wind turbines and power grid. When a grid fault occurs, new transient characteristics in weak grid integrated with doubly-fed induction generators(DFIGs) may present, such as voltage phase angle jump. Current control strategies for wind turbine with strong grid connection are hard to be adapted under weak gird connection. This paper explores the transient characteristics of DFIGs under voltage phase angle jump through analyzing the operation and control characteristics of DFIGs connected into weak grid when the voltage phase angle jumps. Fault ride through(FRT) control strategy of DFIGs based on adaptive phase-locked loop is proposed to adapt weak grid condition. The reference frame of the proposed strategy will be changed in real-time to track the operation condition of DFIGs according to the terminal voltage, and different phase tracking method is adopted during the grid fault. Field data analysis and time domain simulation are carried out. The results show that voltage phase angle jumps when a grid fault occurs, which weakens the FRT capability of DFIGs, and the proposed FRT control strategy can optimize transient characteristics of DFIGs, and improve the FRT capability of DFIGs.

Cytochrome-mediated direct electron uptake from metallic iron by Methanosarcina acetivorans

Impact statement Methane-producing microorganisms accelerate the corrosion of iron-containing metals.Previous studies have inferred that some methanogens might directly accept electrons from Fe(0),but when this possibility was more intensively investigated,H2 was shown to be an intermediary electron carrier between Fe(0)and methanogens.Here,we report that Methanosarcina acetivorans catalyzes direct metal-to-microbe electron transfer to support methane production.Deletion of the gene for the multiheme,outer-surface c-type cytochrome MmcA eliminated methane production from Fe(0),consistent with the key role of MmcA in other forms of extracellular electron exchange.These findings,coupled with the previous demonstration that outer-surface c-type cytochromes are also electrical contacts for electron uptake from Fe(0)by Geobacter and Shewanella species,suggest that the presence of multiheme c-type cytochromes on corrosion surfaces might be diagnostic for direct metal-to-microbe electron transfer and that interfering with cytochrome function might be a strategy to mitigate corrosion.