Modal Frequency Prediction of Chladni Patterns Using Machine Learning

The introduction of machine learning (ML) in the research domain is a new era technique. The machine learning algorithm is developed for frequency predication of patterns that are formed on the Chladni plate and focused on the application of machine learning algorithms in image processing. In the Chladni plate, nodes and antinodes are demonstrated at various excited frequencies. Sand on the plate creates specific patterns when it is excited by vibrations from a mechanical oscillator. In the experimental setup, a rectangular aluminum plate of 16 cm x 16 cm and 0.61 mm thickness was placed over the mechanical oscillator, which was driven by a sine wave signal generator. 14 Chladni patterns are obtained on a Chladni plate and validation is done with modal analysis in Ansys. For machine learning, a large number of data sets are required, as captured around 200 photos of each modal frequency and around 3000 photos with a camera of all 14 Chladni patterns for supervised learning. The current model is written in Python language and model has one convolution layer. The main modules used in this are Tensor Flow Keras, NumPy, CV2 and Maxpooling. The fed reference data is taken for 14 frequencies between 330 Hz to 3910 Hz. In the model, all the images are converted to grayscale and canny edge detected. All patterns of frequencies have an almost 80% - 99% correlation with test sample experimental data. This approach is to form a directory of Chladni patterns for future reference purpose in real-life application. A machine learning algorithm can predict the resonant frequency based on the patterns formed on the Chladni plate.

Landscape Ecology:Coupling of Pattern,Process,and Scale

Landscape ecology provides new theoretical frameworks and methodologies for understanding complex ecological phenomena at multiple scales.Studies of landscape ecology focus on understanding the dynamics of eco-logical patterns and processes,and highlight the integration of multiple disciplines.In this paper,we discussed the problems and challenges that landscape ecology is currently facing,emphasizing the limitations of current methods used to describe dynamic landscape patterns and processes.We suggested that the focus should be on the integration of ground-based observation,mobile monitoring,transect survey,and remote-sensing monitoring,as well as improved coupling of experimental and model simulations.In addition,we outlined the research frontiers in landscape ecology,including scaling,integrated pattern and process modeling,and regional synthesis.Lastly,a brief review of pat-tern-process-scale coupling studies in China was provided.We concluded by pointing out that pattern-process-scale interactions,correlations between natural,economic,and social processes,and the coupling of human and natural systems will be major research areas in landscape ecology in the future.

Dynamic evolution patterns of the degree of ground resistivity anisotropy and the sets mogenic process

Following a new train of thinking, this paper has explored first the potential information in the ground resistivitydata observed by the existing geoelectric observation system, investigated and proposed a new dimensionlessgeoelectric precursor factor, the degree of ground resistivity anisotropy, S, and studied the characteristics of dynamic evolution pattern of S during the seismogenic process. The results show that, during the seismogenic process, the degree of ground resistivity anisotropy (S) displays h process of 'normal' → 'abnormal strengthening(amplitude, range)' → 'abnormal weakening'→ 'earthquake occurrence'→ 'normal'. The earthquake wouldoccur at the time when the S value has entered the late stage of strengthening and turns to weaken and in the gradient belt on the margin ofS anomaly region. The dynamic evolution pattern ofS reflects the changes of the tectonicstress field during the seismogenic process. Therefore, it would be possible to trace the process of earthquake generation and occurrence from the dynamic evolution pattern ofS so as to service eaJ'thquake prediction.

Modeling study on the flow patterns of gas–liquid flow for fast decarburization during the RH process

A water model and a high-speed video camera were utilized in the 300-t RH equipment to study the effect of steel flow patterns in a vacuum chamber on fast decarburization and a superior flow-pattern map was obtained during the practical RH process. There are three flow patterns with different bubbling characteristics and steel surface states in the vacuum chamber： boiling pattern（BP）, transition pattern（TP）, and wave pattern（WP）. The effect of the liquid-steel level and the residence time of the steel in the chamber on flow patterns and decarburization reaction were investigated, respectively. The liquid-steel level significantly affected the flow-pattern transition from BP to WP, and the residence time and reaction area were crucial to evaluate the whole decarburization process rather than the circulation flow rate and mixing time. A superior flow-pattern map during the practical RH process showed that the steel flow pattern changed from BP to TP quickly, and then remained as TP until the end of decarburization.

Effect of process parameters on density of magnesium alloy parts by low-pressure expendable pattern casting

The combination of magnesium alloys with the low-pressure expendable pattern casting(LP-EPC) process would bright future for application of magnesium alloys. The researches are focused on the effect of process parameters on the internal casting quality of magnesium alloy parts. AZ91D magnesium alloy castings were produced for different combinations of the LP-EPC process parameters. Specifically,pouring temperature,vacuum,filling velocity and coupling action of these factors were manipulated to observe their effect on the casting porosity and density distribution. The results indicate that the pouring temperature with LP-EPC process is lower than it in gravity casting. The selected process parameters,such as vacuum,filling velocity and coupled modes of them,must ensure melt metal flowing front profile exhibiting smooth and convex shape. The optimal process parameters for the castings are pouring temperature 983-1 023 K,vacuum 0.02-0.03 MPa,filling velocity 60-95 mm/s,and simultaneous filling with sucking.

An overview of the spatial patterns of land surface processes over arid and semiarid regions

With data from the project Collaborative Observation of Semi-arid/Arid Regions in North China, collected during July and September 2008, the spatial patterns of land surface processes over arid and semiarid regions have been investigated based on the ordinary Kriging interpolation approach. Generally, for the radiation processes, downward and upward short-wave radiation have a uniformly increasing trend with latitude, but the spatial patterns of long-wave radiation present notable regional differences: both upward and downward long-wave radiation increase with latitude in the west of North China, while in the east they vary inversely with latitude, suggesting surface temperature and clouds respectively have feedbacks to the long-wave radiation in the west and east of North China. The surface net radiation basically has a negative latitudinal trend. Long-wave radiation budget plays an important role in the spatial pattern of surface net radiation, particularly in the east of North China, although short-wave radiation budget largely determines the magnitude of surface net radiation. For the energy processes, latent and sensible heat flux varies conversely with latitude: more available land surface energy is consumed by evaporating soil water at lower latitudes while more is used for heating the atmosphere at higher latitudes. A soil heat flux maximum and minimum are found in Loess Plateau and Qinghai Plateau respectively, and a maximum is seen in the northeast China.

Experiments on Development of Channel Pattern in the Process of River Reformation

The changing of flow conditions caused by construction of hydro-projects will result in river's refor- mation and development of channel pattern.In this paper,the development of channel pattern in the process of reformation is studied by means of flume experiments.Influence of slope,grain size,angle-of-inflow,dis- charge and discharge process are comprehensively analyzed according to the experimental data.It was found that the channel would be widened as the river slope or discharge increased and grain s...

Metallogenic Processes:Evidencesfrom Zoning Patterns of Mineralization and alteration and fluid inclusion geochemistryin the Lehong Zn-Pb Deposit in Northeastern Yunnan, China

1 Introduction The large clusters of Zn-Pb deposits in northeastern Yunnan,located in the southwestern margin of the Yangtze Block,are an important part of the Sichuan-YunnanGuizhou Pb-Zn Poly-metallic Metallogenic Triangle Area

APPEARANCE PATTERN OF TOOTH GERMS WITH DEVELOPMENTAL PROCESS IN MYLOPHARYNGODON PICEUS

The pharyngeal dental formula of Mylopharyngodon piceus is 4-5 as a rule, and the dentition isasymmetrical. It is difficult to identify each tooth in the larval dentition. In this paper the appearancepattem of tooth germ with developmental process in this fish is described in detail. The formationpattern of the left dentition is contrasted with that of the right one. In the developmental process,the left pharyngeal dentition lacks teeth at position An3. Thus the left dentition is D-type as designatedby Nakajima(1984), while the right one is A-type.

组织变革情境下高管团队断层激活过程的多案例研究

基于组织变革情境,以5家存在高管团队断层现象的企业为研究对象,采用探索性多案例研究方法,运用扎根理论构建组织变革中高管团队断层激活过程与激活模式模型。研究结果表明:组织变革背景下,高管团队断层涉及利益相关断层、权威特征断层及信息认知断层3种类型;三者的激活过程均体现为高管团队构成因素与结构因素在情境因素的催化下引起成员的亚群体归类行为,进而激活断层;三者在断层激活的条件基础和情境动力方面又存在一定差异性,分别侧重于利益要素、资源要素和信息要素驱动断层激活过程;不同类型断层间还存在交互作用,导致各高管团队断层强度呈现明显不同,依据成员间的分化程度可能呈现出平稳式、分化式、激化式3种激活模式。

Effect of Vibrational Modes on Sand Pressure and Pattern Deformation in the EPC Process

During the EPC (expendable pattern casting) process, one of the essential requirements is to prevent pattern distortion duringsand filling and compaction. A new method which vibrates the system in a two-dimensional circular mode has been appliedto the EPC process. The molding properties of unbonded sand obtained by this new vibration mode are investigated andcompared with those in the one-dimensional vertical mode. For adequate compaction of sand. the circular vibration mode ismore effective than the vertical mode. Sand became more fluidized by the circular vibration and the particle pressure coefficientwas close to unity The particle pressure coefficient, which is defined as the ratio of horizontal to vertical sand pressure, isresponsible for the effectiveness of sand filling.

白地黑花瓷黑彩的仿制及呈色研究

白地黑花瓷是先民创造性以低品位原料生产的一类绘画装饰瓷,在我国北方地区广为烧造,今天仍然有广泛的市场。其中的黑彩,多选自当地的贫铁矿烧成,但外观受多种因素影响。采用考古实验法,通过古瓷样品的测试分析,确定黑彩的组成与施彩工艺。后选用耀州窑陈炉当地制瓷原料,在电窑中以中性气氛烧成,仿烧了耀州窑白地黑花瓷黑彩;采用X射线荧光光谱仪(XRF)、色度仪、超景深显微镜、X射线衍射仪(XRD)、显微共聚焦激光拉曼光谱仪(Raman)等测试分析探讨了烧成温度、彩料的Fe_(2)O_(3)含量、施釉厚度等黑彩呈色的影响。对比发现,仿烧样品基本达到明代白地黑花瓷黑彩的效果。研究结果有助于深入探讨耀州窑白地黑花瓷的地方特色的形成因素,为进一步认知古代白地黑花瓷的科学内涵及地域特色建立理论与实验基础。

小波分析概述:从信号处理的视角

本文从信号处理的视角对20世纪80年代末兴起的小波分析做一个通俗的概述.内容包括小波分析产生的基本问题背景和关键历史事件,小波分析的基本理论,及其对信号处理的意义和作用.希望透过本文能科普性地展示小波的基本理论以及为什么要建立这样的理论.除此以外,笔者还对小波分析之后时频分析领域所出现的经验模型分解方法和图信号处理的基本问题给出简要的介绍.作为中山大学百年校庆的约稿综述,本文对中山大学小波分析研究团队的基本阵容以及历年来所开展的重要学术事件进行了简单的回顾.

湖南省城乡融合发展的时空格局与响应过程

城乡融合发展是城乡关系的高级形态和必然趋势,探究湖南省城乡融合发展的基本规律,对协调全省城乡关系、助推乡村振兴、实现高质量发展具有重要意义。采用主成分分析、聚类分析和地理信息系统(GIS)方法,探讨基于全省14个市州的城乡融合发展时空演变格局及响应模式。结明表明:全省各市州城乡融合发展水平普遍较低,其中城乡经济融合与城乡社会融合发展水平是城乡差距扩大的主要原因;全省不同地区城乡融合发展水平表现出一定的空间集聚性,可将湖南省内各市州城乡融合发展水平由高到低依次分为4类,Ⅰ类为益阳,Ⅱ类包括常德、永州,Ⅲ类包括株洲、邵阳、娄底、岳阳、张家界、湘西、湘潭、郴州、衡阳、长沙,Ⅳ类为怀化;2016—2022年,湖南全省各市州的城乡融合发展差距呈扩大趋势,且在湖南中北部地区与西部地区分别存在“高-高”“低-低”的空间集聚中心。

Optimization and Process Design Tools for Estimation of Weekly Exposure to Air Pollution Integrating Travel Patterns during Pregnancy

A growing number of international studies have highlighted that ambient air pollution exposures are related to different health outcomes. To do so, researchers need to estimate exposure levels to air pollution throughout everyday life. In the literature, the most commonly used estimate is based on home address only or taking into account, in addition, the work address. However, several studies have shown the importance of daily mobility in the estimate of exposure to air pollutants. In this context, we developed an R procedure that estimates individual exposures combining home addresses, several important places, and itineraries of the principal mobility during a week. It supplies researchers a useful tool to calculate individual daily exposition to air pollutants weighting by the time spent at each of the most frequented locations (work, shopping, residential address, etc.) and while commuting. This task requires the efficient calculation of travel time matrices or the examination of multimodal transport routes. This procedure is freely available from the Equit’Area project website: (https://www.equitarea.org). This procedure is structured in three parts: the first part is to create a network, the second allows to estimate main itineraries of the daily mobility and the last one tries to reconstitute the level of air pollution exposure. One main advantage of the tool is that the procedure can be used with different spatial scales and for any air pollutant.

体育表演类课程过程性考核构建探索

过程性考核是将过程与结果相结合的综合考核方式,是从培养目标的视角,对学生的学习态度、学习过程、学习方法以及学习效果的多维度考核。过程性考核就是将教学互动过程通过教师传授知识技能、布置任务,学生掌握基本知识技能、完成任务,再通过阶段检验、终结检验,给出评价的过程来完成。因此,过程性考核对于实践性很强的体育表演类课程具有不可比拟的优势。文章在对体育表演类课程过程性考核内涵的研究以及考核现状分析的基础上,探讨体育表演类课程过程性考核模式的构建,提出构建时要注意:持续性检测,驱动学生学习兴趣与学习投入;多元化评价,驱动教学创新与优化学习方式;多维度考核,驱动学生自主学习与合作学习;优化评价模式,驱动过程性考核评价模式运用与实施。对平时考核、实践考核、期末展演三大板块的考核内容、考核方式等进行设计建构,通过套餐制和积分制等手段构建多样化的考核内容和多元化的评价方法。

传统钩编花样设计与工艺虚拟仿真实验

针对钩编花样设计与工艺实验教学中存在的制作周期长、打样成本高、成品产出效率低、学生参与度低的问题,探索应用现代信息化技术和虚拟现实技术,构建以学生为主体、问题为导向、以虚促实为原则的钩编花样设计与工艺虚拟仿真实验。设计3个实验阶段、4个实验模块和13个主要交互性实验操作步骤,以期打破时空限制,提高实验效率和质量,激发学生学习和创作热情,提升学生实验操作能力、自主学习能力和创新能力,推动高校教学改革和发展,培养应用型专业人才。

基于层次分析与二十四节气动态图案文化基因的设计研究

目的运用动态图案的独特性质和优势,提升视觉体验,超越传统的二维界限。采用创新、生动且引人入胜的数字化方法展示内容,增强中华传统文化对公众的吸引力,促进非物质文化遗产在数字时代的繁荣发展。方法利用层次分析法的相关理论,对二十四节气的物候特征、农事活动特征等相关文化因子进行分析,提炼出节气的文化的典型基因,并将其转换为设计元素,从而构建二十四节气动态图案设计。结果将层次分析法和符号学理论运用到二十四节气动态图案设计中,确定影响二十四节气动态图案设计的典型因子,成功完成了该研究的创新设计方向以及具体方案。结论使用层次分析法和符号学理论进行二十四节气动态图案设计的创新研究,能够清晰了解设计中的典型因子,并进行设计定义和方向决策,顺利完成了研究目标,提升了二十四节气文化新的时代内涵。

电子鼻技术及其应用研究进展

电子鼻(Electronic nose,E-nose)技术作为一种有效的嗅觉模拟与气体识别的方法被广泛应用。电子鼻系统由气体传感器阵列组成,利用其交叉敏感性对气体进行检测。电子鼻系统利用机器学习算法,对气体进行定性定量分析。传统的机器学习算法在电子鼻系统中的应用已经成熟,如今深度学习算法也慢慢在电子鼻系统中应用。电子鼻系统具有选择性高、精密度好、反应快速、稳定性和延展性好的特点,被应用于包括有毒气体检测、空气质量管理、食品新鲜度和质量预测等方面。本文从气体传感器阵列的组成、信号采集与处理单元、模式识别算法的分类以及电子鼻系统在实际中的应用等方面综述了电子鼻系统气体识别的最新研究进展,最后对电子鼻系统气体识别目前所存在的问题以及发展前景进行了总结和展望。

城市地区场次降雨时空展布方法研究

受气候变化和城市规模不断扩张等因素影响,城市地区降雨过程的时空动态性愈发明显,通常采用的点、面雨量等表达方式难以体现这种时空动态性。随着降雨观测技术的进步,大多城市积累了长序列降雨观测数据,其中蕴含了丰富的降雨时空过程信息,为预报降雨或设计降雨的时空展布提供了可能。设计了一套降雨时空展布方法,包括数据收集、标准化处理、降雨场次划分、时空模式提取、标准网格插值、时空展布等环节,并提出每个环节的处理步骤和关键问题。以北京市为例,对该技术方法进行了验证,选择了12 h、24 h、72 h 3个历时的场次降雨,提取的时空模式和展布结果表达出了场次降雨的时空动态性,并与历史的降雨过程表现出很好的匹配性。表明该方法可用于城市地区降雨典型模式提取,以及降雨过程的时空展布。该方法利用历史降雨数据提取降雨展布模板,输入场次降雨(或预报降雨)的总雨量,得到该场次降雨的时空分布过程,展布结果可为洪水预报提供更为准确的降雨输入条件。