A Rapidly Convergence Algorithm for Linear Search and its Application

The essence of the linear search is one-dimension nonlinear minimization problem, which is an important part of the multi-nonlinear optimization, it will be spend the most of operation count for solving optimization problem. To improve the efficiency, we set about from quadratic interpolation, combine the advantage of the quadratic convergence rate of Newton's method and adopt the idea of Anderson-Bjorck extrapolation, then we present a rapidly convergence algorithm and give its corresponding convergence conclusions. Finally we did the numerical experiments with the some well-known test functions for optimization and the application test of the ANN learning examples. The experiment results showed the validity of the algorithm.

Egg investment strategies adopted by a desertic passerine, the Saxaul Sparrow(Passer ammodendri)

Background:As one of the reproductive strategies adopted by bird species,variation in investment in egg production and its influencing factors are important and well-studied subjects.Intraclutch changes in egg size associated with laying order may reflect a strategy of"brood survival"or"brood reduction"adopted by female birds in different situations.Methods:We conducted field studies on the breeding parameters of the Saxaul Sparrow(Passer ammodendri)in Gansu Province,China from 2010 to 2017,to clarify the factors affecting the egg investment and reproductive performance of this passerine species.Results:Our results revealed significant differences in clutch size,egg size and the fledging rate between the first and second brood of Saxaul Sparrows and suggested that this typical desert species allocates more breeding resources to the more favourable second brood period,leading to greater reproductive output.Female body size presented a positive relationship with egg size,and male body size presented positive relationships with clutch size and hatchability.The females that started their clutches later laid more eggs,and hatchability and the fledging rate also increased with a later laying date in the first brood period.With successive eggs laid within the 5-egg clutches(the most frequent clutch size),egg size increased for the first three eggs and then significantly decreased.Conclusions:Our results indicate that female Saxaul Sparrows increased egg investment because of good quality of paired males and good environmental conditions.The intraclutch variation of egg size suggests that this species inhabiting an arid environment adopts a"brood reduction"strategy.

Defect-modulated synthesis and optoelectronic properties in chemical vapor deposited CsPbBr_(3) microplates

The remarkable optoelectronic features of halide perovskite promote their potential applications in semiconductor devices beyond solar cells,which require high-quality single crystals with controlled defect levels.Herein,we investigated the synthesis mechanism of chemical vapor deposited single-crystalline all-inorganic perovskite microplates(MPs),and reported a defect-modulated photocurrent which is closely related to the growth sequence of the MPs.The MP synthesis initiates from island-like nano-disks,and subsequently transits to a layer-by-layer fashion,resulting in a defect-rich area at the center of the MPs.At elevated temperatures,these central defects may be thermally activated and become highly mobile,leading to photoluminescence quenching and degression of local and overall optoelectronic attributes,as evidenced by the spatial resolved optical and electrical scanning probe microscopy.Overall,this work shines light on the formation,proliferation and dynamics of defects in perovskites,and offers guidance for preparation of high-quality perovskites micro-crystals for functional semiconductor devices with high temperature stability.

An Interfacial Gel Electrode Patch with Tunable Hydrogen Bond Network for Electromyographic Sensing and Discrimination

The sensitivity and fidelity of surface electromyography(sEMG)signal monitoring is critical for muscle status and fatigue assessment,prosthetic control,and gesture recognition.However,the incompatible skin-electrode interface and complex electrophysiological environment restrict the sensitive acquisition and accurate analysis of sEMG signals.Focused on the impedance of the skin-electrode interface issue,we developed an interfacial gel electrode patch with a tunable hydrogen bond network to simultaneously achieve a conformal interface,suitable adhesion,and high conductivity for sEMG signal monitoring.By exploiting hydroxyethylidene diphosphonic acid(HEDP)and 2-hydroxyphosphono-acetic acid(HPAA)as hydrogen bonding regulators were introduced into the polyvinyl alcohol(PVA)-based hydrogel network to regulate the hydrogen bond cross-linking network.As a result,the balance of elastic modulus,adhesion,and electrical conductivity of PVA-HEDP-HPAA(PHH)hydrogel are achieved.The reliable electrodeskin interface is manipulated to achieve conformal contact by matching the elastic modulus,reducing the gap of electrode-skin interface by adhesion,and promoting ion and electron conduction by electrical conductivity.The PHH electrode patches exhibit a lower interfacial impedance(12.56 kΩ)and a signal-to-noise ratio of 38.09±1.28 dB for accurate analysis of muscle strength and evaluation of the fatigue state.With the assistance of the artificial neural network algorithm,seven gestures can be recognized with 100%prediction accuracy.The interfacial gel electrode patch contributes a bio-matching electrophysiological platform for prosthetic control,human–machine interaction,and clinical or athletic auxiliary monitoring.

THE NYSTROM METHOD FOR ELASTIC WAVE SCATTERINGBY UNBOUNDED ROUGH SURFACES

We consider a numerical algorithm for the two-dimensional time-harmonic elastic wave scattering by unbounded rough surfaces with Dirichlet boundary condition.A Nystr¨om method is proposed for the scattering problem based on the integral equation method.Convergence of the Nystr¨om method is established with convergence rate depending on the smoothness of the rough surfaces.In doing so,a crucial role is played by analyzing the singularities of the kernels of the relevant boundary integral operators.Numerical experiments are presented to demonstrate the effectiveness of the method.Mathematics subject classification:35P25,45P05.

利用红外相机监测甘肃安西极旱荒漠国家级自然保护区鸟兽物种多样性

为了系统掌握甘肃安西极旱荒漠国家级自然保护区野生动物的种类、数量、分布以及种群动态变化趋势,我们于2017年8月至2019年9月,在保护区选取3个样地布设60台红外相机,对保护区兽类和鸟类多样性进行调查。红外相机累计观测29,147个工作日,采集独立有效照片11,134张。共观测到兽类6目10科18种,鸟类7目16科31种。国家I级重点保护野生动物有5种,国家Ⅱ级重点保护野生动物有11种。兽类中相对多度较高的物种有蒙古兔(Lepus tolai,RAI=12.749)、岩羊(Pseudoisnayaur,RAI=4.690)、北山羊(Caprasibirica,RAI=4.333)、蒙古野驴(Equus hemionus,RAI=3.163)、赤狐(Vulpes vulpes,RAI=2.601),分布最普遍的是赤狐和蒙古兔;鸟类中相对多度较高的物种有石鸡(Alectoris chukar,RAI=1.678)、岩鸽(Columba rupestris,RAI=1.142)、漠?(Oenanthe deserti,RAI=0.865)、赭红尾鸲(Phoenicurus ochruros,RAI=0.374)和沙?(Oenanthe isabellina,RAI=0.196),其中漠?和石鸡的分布最广。豺(Cuon alpinus)、石貂(Martes foina)、黄鼬(Mustela sibirica)和白唇鹿(Cervus albirostris)为保护区新记录物种,雪豹(Pantherauncia)也是保护区建立以来首次观测到。保护区人为干扰减少是造成物种新分布、数量增多的主要原因。

科学训练辅助:柔性可穿戴传感器运动监测应用

竞技体育是国家体育发展水平的核心竞争力.现代竞技体育训练追求运动成绩不断提高,高水平运动员越来越依赖科学定制的个性化训练规划.随着柔性电子、多功能器件集成、人工智能等技术不断进步,运动传感器逐渐向智能化、多元化、微型化、柔性可穿戴化发展,可以对运动员训练过程产生的信号进行全方位、多角度、多层次采集,通过构建高水平运动员运动数据库,运用大数据分析,实时监控运动员的各项生理指标,预测运动员训练存在的风险,进行合理规避运动损伤,为运动员以及教练团队提供科学化的训练方案.本文从运动员训练中对各种体征信号采集、分析的需求出发,综述了近些年来柔性电子、光电可穿戴传感器的最新研究进展,介绍了不同种类的运动信号检测方法,包括电生理信号监测、电化学传感监测、光电容积描记法监测等,为我国运动员与体育工作者提供最新、最前沿的可穿戴传感器技术总结,为制定更为精准、可量化的科学训练方法与理论提供知识与技术支持,推动我国体育强国建设.