Realizing profits immediately:disposition effect of open-end fund investors in China

This paper explores the disposition effect, the tendency of investors to hold losing investments too long and sell winning investments too soon, by analyzing a unique data set that consists of the buying and selling positions of open-end fund investors in China. Results show that investors' buying and selling behaviors are significantly affected by fund performance. The reasons that lie behind such results are mainly related to the non-persistence of fund performance. When fund performance is non-persistent, investors are not clear about the future returns on funds. So, investors, especially individual investors, would have to realize the profits on hand immediately. Meanwhile, fund investors are highly sensitive to fund age and loading fees, but not sensitive to management fees charged by funds when they buy or sell fund shares.

Effect of joints on microwave fracturing of the Bukit Timah granite using an open-ended antenna

Microwave fracturing of rocks before mechanical breakage could improve the performance of mechanical excavators and reduce environmental impacts.Previous research focused on the microwave fracturing of intact rock blocks.By using an open-ended antenna,this paper investigates the effect of pre-existing joints on the microwave fracturing of the Singapore Bukit Timah granite blocks.The results show that the specimens are weakened in the manners of cracking,spalling,melting,or a combination of them.The crack number and the total crack length produced by microwave treatment of jointed rock blocks are slightly smaller than those in the intact rock blocks.The interaction between joints and microwave-induced cracks can be summarized into the following four patterns:(1)microwave-induced cracks become arrested so that the crack propagation is terminated;(2)microwave-induced cracks penetrate the joints and continue to propagate;(3)microwave-induced cracks become deflected along the joints;and(4)microwave-induced cracks propagate forward following the joints.The smaller the approach angle between the microwave-induced crack and the preexisting joint is,the more microwave-induced cracks tend to be arrested at the joint.Increasing the approach angle between the microwave-induced crack and the joint can increase the chance of microwave-induced crack penetrating the joint.The results also show that the smaller the distance is between the microwave radiation point and the joint,the easier it is for microwave-induced cracks to penetrate the joints;otherwise,the microwave-induced crack is more likely to be arrested at the pre-existing joint.

Study on the squeezing effect of open-ended pipe piles

During the installation of a pipe pile,the soil around the pile will be squeezed out. This paper deals with this squeezing effect of open-ended pipe piles using the cylindrical cavity expansion theory. The characteristics of soil with different tension and compression moduli and dilation are involved by applying the elastic theory with different moduli and logarithmic strain. The closed-form solutions of the radius of the plastic region,the displacement of the boundary between the plastic region and the elastic region and the expansion pressure on the external surface of the pipe piles are obtained. When obtaining these solutions,the soil plug in the open-ended pipe pile is considered by employing an incremental filling ratio to quantify the degree of soil plugging. Moreover,the effects of the ratio of tension and compression moduli,angle of dilation and incremental filling ratio on the radius of the plastic region and the expansion pressure on the external surface of the pipe pile are investigated. The parametric analyses show that it is necessary and important to consider the difference between the tension modulus and compression modulus,dilation angle and incremental filling ratio for studying the squeezing effect of open-ended pipe pile installation. It is concluded that the analytical solutions presented in this paper are suitable for studying the squeezing effect of open-ended pipe piles.

Zero-Sequence Current Suppression Strategy for Open-End Winding Permanent Magnet Synchronous Motor Based on Model Predictive Control

Compared with the traditional three-phase star connection winding,the open-end winding permanent magnet synchronous motor(OW-PMSM)system with a common direct current(DC)bus has a zero-sequence circuit,which makes the common-mode voltage and the back electromotive force(EMF)harmonic generated by the inverters produce the zero-sequence current in the zero-sequence circuit,and the zero-sequence current has great influence on the operation efficiency and stability of the motor control system.A zero-sequence current suppression strategy is presented based on model predictive current control for OW-PMSM.Through the mathematical model of OW-PMSM to establish the predictive model and the zero-sequence circuit model,the common-mode voltage under different voltage vector combinations is fully considered during vector selection and action time calculation.Then zero-sequence loop constraints are established,so as to suppress the zero-sequence current.In the end,the control strategy proposed in this paper is verified by simulation experiments.

Reform and Practice of an Engineering Postgraduate Training Pattern in an Open-Ended Base:Taking Foshan Base as an Example

The flawed engineering practice is considered the main factor that is affecting to the development quality of engineering postgraduates.Taking Foshan Base as an example,this paper has analyzed the operational pattern,practice teaching model,and internal governance system of the open-ended base as a new system for engineering practice and proposed several suggestions for the reformation of engineering postgraduates based on the construction effect.

Design and analyses of open-ended pipe piles in cohesionless soils

Large open-ended pipe pile has been found to be advantageous for use in transportation projects. The current design method, however, is not adequately developed. To close this practice gap, this paper first summarized different design methods for open-ended pipe piles in sandy soils. A major factor for all the design codes is to properly account for the formation and effects of soil plug. The comparison indicates that there is a large variation in the base capacity evaluation among different methods due to the complex behaviors of soil plug. To close the knowledge gap, discrete element method （DEM） was used to simulate the soil plugging process and provide insight on the plugging mechanism. The simulation results show that the arching effect significantly increases the internal unit shear resistance along pipe piles. The porosity distribution and particle contact force distribution from DEM model indicate a large stress concentration occurs at the bottom of the soil plug. Besides, nearly 90% of the plug resistance is provided by the bottom half portion of the soil column. The soil-pile friction coefficient has a significant effect on the magnitude of plug resistance, with the major transition occurred for friction coefficient between 0.3 and 0.4.

A newly developed open-end intracranial hematoma drainage tube

Objective: To design a new open-end intracranial hematoma drainage tube for clinical application. Methods: The newly developed device consists of two parts: the plunger and barrel.On one side, the barrel is bullet shaped with an opening tip. The plunger is located in the middle cavity of the tube barrel and extended out at the open-end. It was designed for strengthening the tube barrel and for convenience in performing the drainage procedure. It can be used by inserting the drainage tube into the lesion and pulling out the plunger, whereby blood will forcefully rise up inside the barrel, providing a satisfactory outcome. It is made for effusion drainage purposes. During the procedure, the drainage tip is placed at the deepest part of the intracranial hematoma to completely drain the blood. Moreover, the plunger fits tightly in the tube, preventing leakage during the operation. With the use of the device, brain can be separated. In addition, the device can help reduce the risk of cerebral damage because of the small operating area. The barrel sidewall has matching opening holes bilaterally and equally for exchanging substances between the inner and outer parts.The overlapping ratio in each horizontal pair is around 1/3–1/2. Each pair on the opposite side will form a different pressure. Thus, the opening holes will not easily get blocked with blood clot. Results: Blood and accumulated liquid from the deepest part of the intracranial hematoma can be directly drawn through the drainage tube without damaging a large area. The tube does not get blocked easily and allows for complete removal of the hematoma. Conclusions: The device is asuitable instrument for clinical application.

Effects of inner sleeves on the inner frictional resistance of open-ended piles driven into sand

In open-ended piles, inner friction is developed between inner pile shaf and the inner soil. Inner frictional resistance depends largely on the degree of soil plugging, which is influenced by many factors including pile diameter, relative density and end conditions of piles. In this paper, effects of inner sleeves on inner frictional resistance are discussed. The experiments were conducted on a medium-dense sandy ground using laboratory-scale piles. It was observed that the piles penetrated under partially-plugged or unplugged state. The results suggest that inner fiictional resistance, Qin increases with sleeve height, l linearly and requires 2D （D is pile outer diameter） of l to produce a large as 50% of Qt by Qin （Qt is total resistance）. The results also indicate that bearing capacity increases with wall thickness at the pile tip, which can be attributed to the increase in annular area. The results also indicate that soil plug height is independent of sleeve height. The results also reveal that the penetration of straight piles is closer to unplugged state than the sleeved piles. The results of incremental filling ratio and plug length ratio also indicate that the degree of soil plugging is affected by the sleeve height.

均质黏性土中静压沉桩桩土界面孔压增量及有效土压室内试验研究

研究饱和黏性土中静压沉桩引起的桩土界面孔压增量及有效径向应力的变化规律对工程实践具有重要意义。利用自制的大比例模型试验系统,通过双壁开口和闭口管桩,实现了开口和闭口桩桩身表面嵌入式安装微型测试元件,得到了考虑孔压增量的桩土界面有效径向应力的变化规律。研究结果表明:入土深度越大,桩土界面孔压增量及有效径向应力越大,闭口桩桩土界面超孔压大于开口桩;桩身上部桩土界面超孔压和有效径向应力小于桩身下部;同一入土深度,随着桩身h/L的增加,桩土界面土压力存在侧压力“退化”的现象;特定试验条件下,闭口和开口桩桩土界面超孔压与上覆有效土体自重比值最大值分别是61.2%和52.1%,桩土界面有效径向应力是超孔压的3.76~5.46倍。桩土界面超孔压和有效径向应力与桩身h/L位置有关。

面向创新人才培养的生物实验课程建设与探究

开放型综合实验课程是在网络化教学管理平台的支撑下,将现代生物技术融入实验教学,强化技能的综合性、创新性、交叉性和自主性,构建不同层次综合实验课程体系,实现实验内容个性化、实验主体自主化、实验模式新型化、实验考核多样化的改革目标。开放型综合实验能有效激发学生的自主学习兴趣,提升实验教学水平,同时有助于加强实验室管理。因此,开放型综合实验在培养创新人才中的作用应被重视,而且这样的模式也应该得到有效推广。

复合式教学法在“遗传学”教学中的应用与实践

“遗传学”是现代生命科学的核心课程,由于学科发展迅速、技术不断进步、知识更新快,传统的授课模式在教学内容、教学方法等方面均存在诸多不足。总结了遗传学教学过程中存在的问题,积极优化教学内容,采用复合式教学法,即启发式、问题式、案例式、科研融入等多种形式针对不同内容选用适合的教学方法,以及科研与教学的有机结合,围绕教材的重点、难点和关键问题,引导学生独立思考。此教学模式充分调动了学生学习遗传学的自主能动性,激发学生的学习兴趣,培养了学生自学、实践和创新能力,提升了学生农业振兴的使命感,取得了良好的教学效果。

Radiation of a TM mode from an open end of a three-layer dielectric capillary

Modern trends in beam-driven radiation sources include the interaction of Cherenkov wakefields in open-ended circular waveguides with complicated dielectric linings, with a three-layer dielectric capillary recently proposed to reduce radiation divergence being a representative example [Opt. Lett. 45 5416(2020)]. We present a rigorous approach that allows for an analytical description of the electromagnetic processes that occur when the structure is excited by a single waveguide TM mode. In other words, the corresponding canonical waveguide diffraction problem is solved in a rigorous formulation. This is a continuation of our previous papers which considered simpler cases with a homogeneous or two-layer dielectric filling. Here we use the same analytical approach based on the Wiener–Hopf–Fock technique and deal with the more complicated case of a three-layer dielectric lining. Using the obtained rigorous solution, we discuss the possibility of manipulating the far-field radiation pattern using a third layer made of a low permittivity material.

L型双输出三电平变换器驱动开绕组电机研究

为简化驱动开绕组异步电机(OEWIM)的双逆变器结构,提出一种L型双输出三电平变换器(L-DO-TLC)拓扑。将T型三电平拓扑与九开关拓扑相结合,通过器件复用方式简化拓扑结构,仅需15个开关器件即可实现双三电平输出,有效降低了系统成本。首先详细分析了L-DO-TLC拓扑工作机理,采用含直流偏置的正弦脉宽调制(SPWM)策略实现了双端口独立输出。在此基础上,根据OEWIM驱动的特殊需求及所提拓扑特点,给出一种双端口互差120°OEWIM驱动接线方案并建立了系统数学模型,给出了电压空间矢量分布图。然后利用矢量解耦思想,对双输出端口调制度进行了研究,确立双端口互差120°OEWIM驱动的稳定运行区间。最后,对所提拓扑及控制策略的可行性和有效性进行了验证。

指向高阶思维能力培养的高考生物学开放性试题分析及启示

开放性试题有着结论开放、情境真实以及要求学生通过复杂认知活动完成作答的特点,是考查学生高阶思维能力的重要题型之一。广东省2023年高考生物学试题中出现了多道开放性试题,通过对试题的分析发现其对学生的多项高阶思维能力展开了考查,也对开放性试题的命制和课堂教学有一定的借鉴意义。

明清仙道小说的结构模式及其来源

明清小说的繁荣,带来了小说观念和小说理论的繁富,小说家纷纷对小说的结构艺术进行深刻思考。在这个背景下,作为明清小说中一个新品种的道教仙道小说,据初步统计共48部,它们的作者都曾苦心经营过这些小说的结构模式,结果是全部48部仙道小说无一例外地按照“仙界开局式”“凡间发展式”“玉局结尾式”,即“仙界→人世→仙界”的三段结构形式来布局谋篇,这种模式同时也策应了明清文法、戏法、小说法等提倡的豹头、猪肚、凤尾的结构理论。究其原因,主要受诸如《太平经》等早期道教在经典制作上的文本模式的影响。但是明清仙道小说在结构安排、叙述风格等方面也存在诸多差异性,这是服从于仙道小说自身发展的内在要求和其他外在客观因素所必然导致的结果。

开放式情境判断测验的自动化评分

受限于评分成本,开放式情境判断测验难以广泛使用。本研究以教师胜任力测评为例,探索了自动化评分的应用。针对教学中的典型问题场景开发了开放式情境判断测验,收集中小学教师作答文本,采用有监督学习策略分别从文档层面和句子层面应用深度神经网络识别作答类别,卷积神经网络(ConvolutionalNeuralNetwork,CNN)效果理想,各题评分准确率为70%~88%,与人类评分一致性高,人机评分的相关系数r为0.95,二次加权Kappa系数(Quadratic Weighted Kappa,QWK)为0.82。结果表明,机器评分可以获得稳定的效果,自动化评分研究能够助力于开放式情境判断测验的广泛应用。

考虑土塞效应的开口管桩沉桩与承载全过程离散元分析

开口管桩贯入过程中会产生复杂的土塞效应,显著影响管桩的沉桩过程与承载特性。考虑到试验方法成本高、周期长、且难以直观反映土塞与管桩的相互作用特性,基于离散元方法开展砂土地基中静压开口管桩沉桩与承载全过程模拟分析。基于室内试验数据对离散元模型参数进行标定,并采用周期性单元复制法生成均质且应力沿深度线性分布的地基模型。基于土体变形特征,揭示管桩中土塞的主动拱与被动拱分布特征。进一步地,结合土塞参数的演化规律,得出土塞增长率(IFR)对土塞状态变化更为敏感,且土塞阻力的发挥趋势与IFR值变化趋势有较高的相似性。基于管桩静载试验模拟,得出静载下开口管桩呈完全闭塞状态,土塞的荷载-位移响应呈弹塑性,并最终建立考虑CPT锥尖阻力、土塞效应、管桩尺寸的静压开口管桩桩端阻力经验计算公式。本文研究成果揭示了土塞的形成演化过程与承载机制,对于考虑土塞效应的开口管桩沉桩阻力预测与承载力计算具有一定参考价值。

《著作权法》作品类型兜底条款的解释论完善

《著作权法》对于作品类型采用了开放式的设计,但缺乏配套法规则不可避免地导致著作权保护范围的不当扩张、向一般条款逃避及如何具体适用等问题,配套法规的及时跟进成为兜底条款得以有效适用的紧迫前提。通过采用形式解释和实质解释结合的方式对开放式作品类型条款的条文、目的、渊源及演变进行分析,建议在《著作权法实施条例》修改中对“其他智力成果”进行界定并采用以“符合作品特征的其他智力成果,是指符合作品特征但依靠其主要表现形式不能认定为本条前8项作品类型的作品”的表述。以进一步明确判断作品类型的分类标准及前8类作品类型优先适用的原则,防止符合多种作品类型特征的智力成果流向兜底条款,有效界分兜底条款与前8类作品类型在调整范围上的边界及与其他法律法规的适用的边界,为开放式作品类型条款的适用提供具体化路径。

六氟环氧丙烷阴离子开环聚合反应研究进展

介绍了六氟环氧丙烷在阴离子催化下的开环聚合反应研究进展,包括聚合反应条件、引发体系、工艺和反应器结构对聚合物特性的影响,并对端基处理后的聚合物在特性单体、乳化剂、润滑剂和材料改性等方面的应用现状和前景进行了分析。