A hyperbolic Lindstedt-Poincare method for homoclinic motion of a kind of strongly nonlinear autonomous oscillators

A hyperbolic Lindstedt-Poincare method is presented to determine the homoclinic solutions of a kind of nonlinear oscillators, in which critical value of the homoclinic bifurcation parameter can be determined. The generalized Lienard oscillator is studied in detail, and the present method＇s predictions are compared with those of Runge-Kutta method to illustrate its accuracy.

A Case Study of the Characteristics of an Autonomous Learner:Take an Adult English Learner for Example

This study based on researcher's adult oral English teaching experience,takes an adult English learner as a case study to explore the characteristics of an autonomous English learner.From analysis of data (observation and teaching diary),this study elaborates three common characteristics of an autonomous learner:(1) Firstly,an autonomous learner has a high motivation;(2) Secondly,an autonomous learner is good at trying different learning strategies,especially metacognitive strategy to manage learning proceeding.(3) Lastly,an autonomous learner readily takes charge of their own learning by making plan and reflecting on it.Meanwhile,this study presents teacher's role as a facilitator and consultor and some factors that need taking into consideration,offering a precious experience for future's fostering of autonomous English learners.

A Study on the Correlations Between Chinese EFL Learners' Autonomous Learning and Their Cooperative Learning

Cooperative learning and learner autonomy have become heated topics in English teaching.Many researchers both at home and abroad have carried out the study on this field,and they proved that learner autonomy and cooperative learning are rel evant,cooperative learning can promote English majors’learning autonomy in terms of listening,reading,speaking,however,no obvious findings in vocabulary and writing.This study is conducted to prove the feasibilities and effectiveness of cooperative learning applied to foster first-year non-English majors’learning autonomy from the aspect of vocabulary and structure.The re sults of this study showed that cooperative learning was much more effective than traditional teaching approaches in fostering some positive affective factors.According to this research,cooperative learning can also improve learners’vocabulary and struc ture significantly.

A Qualitative Study of Non-English Majors' Learner Autonomy in Out-of-class English Learning Contexts

The aim of the study was to explore non-Engish majors' actual practice of out-of class English learning activities and the relationship between out-of-class English learning and language proficiency. Data were gathered through qualitative methods by semi-structured interviews and observation with 6 non-English majors from Tianjin Foreign Studies University. Students' CET-4 scores were collected as well. Out-of-class observation was conducted with two participants who represent respectively high and low scores in CET. The results indicated that high scorers generally showed higher level of learner autonomy in out-of-class learning context. than low scorers. Most of the participants hoped to obtain more guidance and recommendations for learning materials and learning strategies so as to improve their language skills.

An Observational Study of the 30-50 Day Atmospheric Oscillations Part I: Structure and Propagation

Features of structure and propagation of the 30 to SO day atmospheric oscillations are investigated using the ECMWF analysis of 1980-1983. Evidence is provided to confirm the characteristics of the oscillation in the equatorial region. Those in the mid-high latitudes, however, are revealed to be very different from the tropics and pose a strong barotropic structure. Horizontal coherence shows teleconnection patterns which can be identified as EAP and PNA. The wind field of the specified time scale of the oscillation appears as long-lived vortices and vortex pairs. Mid-latitude perturbations propagate clearly westwards, especially during the winter season. In the high latitudes, they propagate westwards in the winter but eastwards in the summer. Meridional propagations are rather different from region to region.

A Technical Framework for Selection of Autonomous UAV Navigation Technologies and Sensors

The autonomous navigation of an Unmanned Aerial Vehicle(UAV)relies heavily on the navigation sensors.The UAV’s level of autonomy depends upon the various navigation systems,such as state measurement,mapping,and obstacle avoidance.Selecting the correct components is a critical part of the design process.However,this can be a particularly difficult task,especially for novices as there are several technologies and components available on the market,each with their own individual advantages and disadvantages.For example,satellite-based navigation components should be avoided when designing indoor UAVs.Incorporating them in the design brings no added value to the final product and will simply lead to increased cost and power consumption.Another issue is the number of vendors on the market,each trying to sell their hardware solutions which often incorporate similar technologies.The aim of this paper is to serve as a guide,proposing various methods to support the selection of fit-for-purpose technologies and components whilst avoiding system layout conflicts.The paper presents a study of the various navigation technologies and supports engineers in the selection of specific hardware solutions based on given requirements.The selection methods are based on easy-to-follow flow charts.A comparison of the various hardware components specifications is also included as part of this work.

Potential Toxicological and Cardiopulmonary Effects of PM2,5 Exposure and Related Mortality:Findings of Recent Studies Published during 2003-2013

Air pollution has environmental issue owing become a serious to its diverse harmful effects on the physical and biological environment. According to the Environmental Protection Agency （EPA） and the World Health Organization （WHO）, air pollution affects millions of people worldwide. Hundreds of thousands of deaths each year and a range of diseases, particularly among vulnerable groups （i.e., children, the elderly, and people with special medical conditions）, are attributed to air pollution. These effects are not always caused by single pollutant in the air; rather, they are considered consequences of the multi-pollutants to which people are simultaneously exposed.

Numerical study on three-dimensional flow field of continuously rotating detonation in a toroidal chamber

Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonation- shock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interest- ing properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.

An Observational Study of the 30-50 Day Atmospheric Oscillations Part II: Temporal Evolution and Hemispheric Interaction across the Equator

In this part, the temporal evolution and interaction across the equator of 30-50 day oscillation in the atmosphere are investigated further. The annual variation of 30-50 day oscillation is quite obvious in the mid-high latitudes. In the tropical atmosphere, the obvious interannual variation is an important property for temporal evolution of 30-50 day oscillation. The low-frequency wavetrain across the equator over the central Pacific and central Atlantic area, the movement of the long-lived low-frequency system across the equator and the meridional wind component across the equator will obviously show the interaction of 30-50 day oscillation in the atmosphere across the equator.

Experimental Study on Momentum Transfer of Surface Texture in Taylor-Couette Flow

The behavior of Taylor-Couette （TC） flow has been extensively studied. However, no suitable torque prediction models exist for high-capacity fluid machinery. The Eckhardt-Grossmann-Lohse （EGL） theory, derived based on the Navier-Stokes equations, is proposed to model torque behavior. This are the significant energy theory suggests that surfaces transfer interfaces between cylinders and annular flow. This study mainly focuses on the effects of surface texture on momentum transfer behavior through global torque measurement. First, a power-law torque behavior model is built to reveal the relationship between dimensionless torque and the Taylor number based on the EGL theory. Second, TC flow appa- ratus is designed and built based on the CNC machine tool to verify the torque behavior model. Third, four surface texture films are tested to check the effects of surface texture on momentum transfer. A stereo microscope and three-dimensional topography instrument are employed to analyze surface morphology. Global torque behavior is measured by rotating a multi component dynamometer, and the effects of surface texture on the annular flow behavior are observed via images obtained using a high-speed camera. Finally, torque behaviors under four differentsurface conditions are fitted and compared. The experi- mental results indicate that surface textures have a remarkable influence on torque behavior, and that the peak roughness of surface texture enhances the momentum transfer by strengthening the fluctuation in the TC flow.

Preparation and spectroscopic, and thermal decomposition kinetic studies of europium(Ⅲ) complex [Eu(HNBD)_3] (HNBD: 1-(6-hydroxy-1-naphthyl)-1,3-butanedione)

The complex of Eu（IH） with 1-（6-hydroxy- 1-naphthyl）- 1,3-butanedione （HNBD） was prepared for the first time and characterized by elemental analysis, IR, UV, fluorescence spectrum, and DTA-TG-DTG techniques. The IR and UV-visible spectra showed that Eu（Ⅲ） ion was coordinated to the HNBD ligand. The fluorescence spectrum showed the presence of Eu^3＋ characteristic emission. The TG-DTA-DTG curves showed that the thermal decomposition of the anhydrous complex was a two-stage process and the final residue was Eu2O3. The thermal decomposition kinetic parameters of the complex were evaluated from TG-DTG data by using three kinds of integral methods （Coat-Redfem equation, Horowitz and Metzger equation, Madhusudanan-Krishnan-Ninan equation）. The kinetic parameters of the first stage are E^＊ = 164.02 kJ.moll, A = 1.31 × 10^15 s^-l, AS^＊= 42.27 J·K^-l·mol^-l, △H^＊ = 159.51 kJ·mol^-l, △G^＊= 136.54 kJ·mol^-l, and n = 3.1, those of the second stage are E^＊= 128.52 kJ·mol^-l, A = 1.44× 106 s^-1, △S^＊= - 136.89 J·K^-l·mol^-l, △H^＊ = 120.41 kJ·mol^-l, △G^＊= 283.85 kJ·mol^-l, and n = 1.1.

Autonomous Learning to Improve College English Students' English Research

This paper aims to resesrch on the autonmons tearning so as to improve the college students’English learning.First ofall,it introdues some basic concepts of the autonomous learning theory,Secondly,it analyzes the current situation of college Eng-lish students’listening and speaking.In this passage the anthor hopes that it is helpful to improve college students’listening andspeaking level by their autonomous learning.It is helpful to improve their listening and speaking ability.As a result,it is helpful todevelop college students’English comprehensive application ability.

Study on the Mercury （11） Complex of 4,5-benzol,2-dithiole-3-thione by IR, Theoricaly and X-Ray

A mercury （II） complex with 4.5-benzo-1.2-dithiol-3-thione （C7H4S3） （1）, [Hg2I4（C7H4S3）2] （2） was synthesized. The structure of the obtained complex （2） was characterized by crystallography, Infrared Spectroscopy （IR） analysis and theoretical study. The complex （2） has a dimeric structure, where each mercury atom takes a tetrahedral geometry and is coordinated by two bridging chloride, one terminal chloride and one thiocarbonyl sulfur atom （C=S） of the ligand.

Decay Study of the Neutron-Rich Nucleus ^(175)Er

The decay of the neutron-rich erbium isotope 175Er is studied by using the reaction176Yb（n,2p）175Er.A partial decay scheme is proposed on the basis of X-γ and γ-γ coincidencemeasurements,taking into account eight observed gamma rays.A ground rotational band is as-signed to 175Tm.Some systematic behaviors of 1/2+[411] ground rotational bands in odd-Athulium are described.The experimental and calculated decoupling parameters of these bandsare compared.

Serum tumor markers (carcinoembryonic antigen, carbohydrate antigen 19-9, carbohydrate antigen 72-4, carbohydrate antigen 24-2, ferritin) and gastric cancer prognosis correlation

BACKGROUND Gastric cancer is a kind of malignant tumor which is prevalent all over the world.Although some progress has been made in the treatment of gastric cancer,its prognosis is still not optimistic,so it is of great significance to find reliable prog-nostic indicators to guide the treatment and management of patients with gastric cancer.AIM To explore the relationship between serum levels of five biomarkers[carcinoem-bryonic antigen(CEA),carbohydrate antigen(CA)19-9,CA72-4,CA24-2,and ferritin]and prognosis in patients with gastric cancer.METHODS This study included 200 patients with gastric adenocarcinoma,and conducted an in-depth analysis of their baseline characteristics,relationship between tumor markers and staging,and prognosis.The study found that CA19-9 has a signi-ficant correlation with tumor stage,the average levels of CA24-2,CEA,CA72-4 and ferritin were slightly increased disregarding the stage of tumor.Survival analysis showed that increases in CEA,CA19-9,CA24-2,and ferritin were all associated with shortened overall survival of patients.Further multivariate ana-lysis revealed that elevated serum CA72-4 levels were an inde-pendent adverse prognostic factor.RESULTS This study reveals that there is a significant correlation between the expression levels of serum tumor markers CEA,CA19-9,CA72-4,CA24-2 and ferritin in patients with gastric cancer and prognosis,and can be used as important indicators for prognostic evaluation of gastric cancer.In particular,markers that appear abnormally elevated initially may help identify gastric cancer patients with poor prognosis.CONCLUSION Serum CEA and CA19-9 play an important role in the prognosis assessment of gastric cancer,and are effective tools to guide clinical practice and optimize individualized treatment strategies for gastric cancer patients.

基于SpringBoot和Uni-App框架的自习室平台的设计与实现

目前,国内教育开始大规模普及在线学习模式。然而,许多现有的在线学习平台逐渐出现过度娱乐化和社交严重化的问题,这严重违背了在线学习平台诞生的初衷;此外,平台功能相对有限,难以全面管理用户的学习状态,市面上满足用户需求的产品也相当匮乏。为此,文中基于SpringBoot和Uni-App框架设计与开发了一款移动端自习室平台,专门为用户提供学习状态管理服务。该平台的主要功能包括自习状态管理、学习动态管理、排行榜、记事本、用户信息管理5大功能模块。该平台可为用户提供一系列学习状态管理服务,帮助用户养成良好的学习自制力,培养学生的自主学习能力,提高学习效率。

自主阅读方式下5-6岁儿童图画书重复阅读的眼动研究

自主阅读和重复阅读是促进学前儿童文字关注的两种阅读方式,为探究将这两种阅读方式结合后儿童对图画书中文字和图画的注视规律及特点,研究选取了31名5-6岁的幼儿进行自主阅读方式下的重复阅读,记录了被试第一、三、五次阅读时的眼动行为,结果发现,在文字注视方面,第三次阅读和第一次阅读相比在首次注视前时间上存在显著下降;在图画注视方面,阅读第三次和阅读第一次之间在注视时长和注视次数这两个指标均存在显著下降。这表明在自主阅读方式下进行重复阅读,随着重复次数的增加,幼儿会更早关注到文字;在图画注视方面,无论是对故事主角或是新事物,幼儿对其的关注度都会随着重复次数的增加而下降。

缺氧诱导因子-1α和BCL-2/腺病毒E1B19 kDa相关蛋白3在中耳胆脂瘤表达及意义

目的探讨缺氧诱导因子-1α(hypoxia inducible factor-1,HIF-1α)和BCL-2/腺病毒E1B19KDa相关蛋白3(Bcl2/adenovirus E1B 19 kD interacting protein 3,BNIP3)在中耳胆脂瘤中的表达及胆脂瘤上皮的凋亡情况。方法采用免疫组织化学方法检测30例中耳胆脂瘤标本与18例外耳道皮肤标本中HIF-1α和BNIP3蛋白的表达情况,使用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记(terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling,Tunel)检测20例中耳胆脂瘤标本和18例外耳道皮肤标本的凋亡情况。使用Pearson相关分析检验HIF-1α和BNIP3蛋白之间的相关性。结果 HIF-1α在胆脂瘤组和对照组的平均光密度分别为0.16±0.07和0.08±0.03,两组比较差异有统计学意义(t=4.279,P<0.01);BNIP3在胆脂瘤组和对照组的平均光密度分别为0.16±0.08和0.11±0.06,两组比较差异有统计学意义(t=2.463,P=0.0185);经pearson相关分析,在胆脂瘤上皮中,HIF-1α和BNIP3之间呈正相关(r=0.418,P=0.003);Tunel染色中,凋亡指数在胆脂瘤组和对照组分别为(52.8±12.5)%和(9.99±2.97)%,两组比较差异有统计学意义(t=14.166,P<0.01)。结论 HIF-1α和BNIP3在中耳胆脂瘤中的异常表达可能与胆脂瘤的高凋亡特性有关。

Ethnobotanical study on medicinal plants from the Dragon Boat Festival herbal markets of Qianxinan, southwestern Guizhou, China

Dragon Boat Festival herbal markets in the Qianxinan Buyi and Miao Autonomous Prefecture of southwestern Guizhou have a long well-conserved history.These markets,which are a feature of Buyi and Miao traditional medicines,contain a rich diversity of medicinal plants and traditional medical knowledge.Today,people in southwestern Guizhou still believe that using herbs during the Dragon Boat Festival prevents and can treat disease.In this study,we identified the fresh herbal plants sold at the herbal markets of Xingren City and Zhenfeng County in Qianxinan Buyi and Miao Autonomous Prefecture and quantified their importance.We identified 141 plant species(belonging to 114 genera and 61 families).The plant family with the most species was Asteraceae(14 species).Informants reported that most medicinal plants are herbaceous,with 95.7%of plants used for decoction and 30.5%used for medicinal baths.Medicinal plants are most commonly used to treat rheumatism,injury,and abdominal diseases.The utilization frequency index and relative importance values indicated that Artemisia argyi and Acorus calamus are the most important plants sold at herbal markets during the Dragon Boat Festival.The price of medicinal materials sold in the market may serve as an indicator of the conservation status of species in the region.These findings indicate that the Dragon Boat Festival herbal markets in the Qianxinan Buyi and Miao Autonomous Prefecture fully embodies the characteristics of indigenous ethnomedicine and culture,and also exhibits the diversity of plant resources.We recommend that rare and endangered plants in this region be domesticated and protected.

Comparative study of HFACS and the 24Model accident causation models

A comparative study is conducted to compare the theory and application effect of two accident causation models, the human factors analysis and classification system（HFACS） and the accident causation ＂2-4＂ model（24 Model）, as well as to provide a reference for safety researchers and accident investigators to select an appropriate accident analysis method. The two models are compared in terms of their theoretical foundations, cause classifications, accident analysis processes, application ranges, and accident prevention strategies. A coal and gas outburst accident is then analyzed using both models, and the application results are compared. This study shows that both the 24 Model and HFACS have strong theoretical foundations, and they can each be applied in various domains. In addition, the cause classification in HFACS is more practical, and its accident analysis process is more convenient. On the other hand, the 24 Model includes external factors, which makes the cause analysis more systematic and comprehensive. Moreover, the 24 Model puts forward more corresponding measures to prevent accidents.