从生物力学角度试论杀球的最佳发力结构

下面发表的为上海体院羽毛球班(包括函授专科班)1982--1984届学生的毕业论文摘编。论文作者进校前一般都具有5至15年从事羽毛球运动的经历。学习期间,他们应用体育基础理论学科知识,对一些羽毛球运动的问题进行了专题探讨。论文涉及的面较广,有论据,有分析,有观点,有一定参考价值。由于论文篇幅较长,除部分全文选用外,其余本刊特请该校指导教师(郁鸿骏、戴金彪、郑金安、李正祁、吕望山等同志)择优摘编刊用,以资参阅。

浅谈拳击中出拳的力量来源及如何正确学习、掌握摆拳拳法

本文对拳击中出拳的力量来源及如何学习、掌握拳击中摆拳拳法，加以分析和探讨。

Research advances in the biological characteristics of the crustacean spermatozoa

The biological characteristics of crustacean spermatozoa is important for the artificial reproduction and genetic breeding. With reference to the latest studies and related materials, this paper reviewed the research progress in the biological characteristics of crustacean spermatozoa, such as morphological structure of sperm, spermatogenesis, sperm viability, preservation in vitro and acrosome reaction et al. The prospects of the research field have also been anticipated.

多维度专项动作练习在立定跳远中的运用

本文根据笔者对立定跳远人体发力结构的研究及立定跳远教学和训练的实践积累，总结出提高爆发力项目之一立定跳远成绩的方法手段。

推铅球技术动作的生物力学分析

从生物力学角度对推铅球滑步、最后用力及出手角度等方面进行了分析,给出了良好的滑步,节奏、形成身体各环节肌群有序而连续不断的发力和最佳出手角度的技术参数,使更有效地提高运动成绩。

短跑起跑与呼吸

许多短跑运动员在进行起跑练习时,只注重运动器官的发力,而忽视呼吸器官的呼吸方法,致使运动器官和呼吸器官配合失调,经常会出现注意力不集中,反应迟钝、启动缓慢、后蹬无力等现象,难以将起跑速度充分发挥出来。在起跑练习时,我们让短跑练习者掌握合理的呼吸方法后,不仅克服了起跑中存在的不良现象,而且能充分发挥出人体起跑的运动机能,对提高运动成绩起到重要的作用。下面将短跑起跑各环节的呼吸方法作一介绍。

Application of Participatory Monitoring and Evaluation in Development of Animal Husbandry Technology

[Objective] This study aimed to provide references for the application of participatory monitoring and evaluation in the development of animal husbandry tech- nology. [Method] With the livelihood improvement program for agricultural and pas- toral area in northern Yunnan as the example, the development process of partici- patory animal husbandry was overviewed. And the monitoring and evaluation pro- cesses of participatory animal husbandry were introduced and analyzed. [Result] The monitoring and evaluation indicator system of participatory animal husbandry technol- ogy included 4 layers, namely technology, institutional system, personnel ability con- struction and effectiveness, and 11 third-level indicators, namely, technical characteristics, superiority-inferiority comparison, community and farmers, technical personnel, project personnel, economic indicators and social indicators. [Conclusion] This study provided the references for the application of participatory monitoring and evaluation in the development of animal husbandry technology.

Resonance Raman Spectroscopic and Theoretical Study of Geometry Distortion of Thiourea in 2^1A State

The A-band resonance Raman spectra of thiourea were obtained in water and acetonitrile solution. B3LYP/6-311＋＋G（3df,3pd） and RCIS/6-311＋＋G（3df,3pd） calculations were done to elucidate the ultraviolet electronic transitions, the distorted geometry structure and the saddle point of thiourea in 21A excited state, respectively. The resonance Raman spectra were assigned. The absorption spectrum and resonance Raman intensities were modeled using Heller＇s time-dependent wavepacket approach to resonance Raman scattering. The results indicate that largest change in the displacement takes place with the C--S stretch mode u6 （｜△｜=0.95） and noticeable changes appear in the H5N3H6＋H8N4H7 wag v5 （｜△｜=0.19）, NCN symmetric stretch^-C--S stretch＋N3H6＋H8N4 wag v4 （｜△｜=0.18）, while the moderate intensities of 2-15 and 4-15 are mostly due to the large excited state frequency changes of v15, but not due to its significant change in the normal mode displacement. The mechanism of the appearance of even overtones of the S-CN2 out of plane deformation is explored. The results indicate that a Franck-Condon region saddle point is the driving force for the quadric phonon mechanism within the standard A-term of resonance Raman scattering, which leads to the pyramidalization of the carbon center and the geometry distortion of thiourea molecule in 21A excited state.

Structural Dynamics of 3-Dimethylamino-2-methyl-propenal in S2（ππ^＊） State

The photophysics of 3-dimethylamino-2-methyl-propenal （DMAMP） after excitation to the S2 （ππ^＊） electronic state was studied using the resonance Raman spectroscopy and complete active space self-consistent field method calculations. The transition barriers of the ground state tautomerization reactions between DMAMP and its three isomers were determined at B3LYP/6-311＋＋G（d,p） level of theory. The vibrational spectra were assigned. The A- band resonance Raman spectra were obtained in acetonitrile with excitation wavelengths in resonance with the first intense absorption band to probe the structural dynamics of DMAMP. The B3LYP-TD computation was carried out to determine the relative A-band resonance Raman intensities of the fundamental modes, and the result indicated that the vibronic-coupling existed in Franck-Condon region. Complete active space self-consistent field （CASSCF） calculations were carried out to determine the excitation energies of the lower-lying singlet and triplet excited states, the conical intersection points and the intersystem crossing points. The A-band short-time structural dynamics and the corresponding decay dynamics of DMAMP were obtained by analysis of the resonance Raman intensity pattern and CASSCF computations. It was found that a sudden de-conjugation between C1=O6 and C2=C3 occurred at the Franck-Condon region of the S2（ππ^＊） state, while the enhancement of the conjugation interaction between C3 and N（CH3）2, and between C1 and C2 evolutions shortly after the wavepacket leaves away the Pranck-Condon region via the excited state charge redistribution. The de-conjugation interaction between C1=O6 and C2=C3 made the rotation of C3=N（CH3）2 group around the C2-C3 bond much easier, while the enhanced conjugation between C1 and C2, and between C3 and N（CH3）2 made the rotation around the C1-C2 bond and C3-N5 more difficult. It was revealed that the initial structural dynamics of DMAMP was predominantly towards the CI-I（S2/S0） point, while the opportunities towards either CI-2（S2/S0） or CI-3（S2/S0） point were negligible. Two decay channels of DMAMP from S2,FC（ππ^＊） to So or Tl,min via various CIs and ISCs were proposed.

Design of Large-Scale Prestressing Bucket Foundation for Offshore Wind Turbines

The key in the force transmission between the tower and the foundation for offshore wind turbines is to transfer the large moment and horizontal loads. The finite element model of a large-scale prestressing bucket founda- tion for offshore wind turbines is set up and the structural characteristics of the arc transition structure of the founda- tion are analyzed for 40-60 channels(20-30 rows) arranged with prestressing steel strand under the same ultimate load and boundary conditions. The mechanical characteristics of the key parts of the foundation structures are illus- trated by the peak of the principal tensile stress, the peak of the principal compressive stress and the distribution areas where the principal tensile stress is larger than 2.00 MPa. It can be concluded that the maximum principal tensile stress of the arc transition decreases with the increasing number of channels, and the amplitude does not change signifi- cantly; the maximum principal compressive stress increases with the increasing number of channels and the amplitude changes significantly; however, for the distribution areas where the principal tensile stress is larger than 2.00 MPa, with different channel numbers, the phenomenon is not obvious. Furthermore, the principal tensile stress at the top of the foundation beams fluctuantly increases with the increasing number of channels and for the top cover of the bucket, the principal tensile stress decreases with the increasing number of channels.

Monitoring of Wind Turbine Blades Based on Dual-Tree Complex Wavelet Transform

Structural health monitoring(SHM)in-service is very important for wind turbine system.Because the central wavelength of a fiber Bragg grating(FBG)sensor changes linearly with strain or temperature,FBG-based sensors are easily applied to structural tests.Therefore,the monitoring of wind turbine blades by FBG sensors is proposed.The method is experimentally proved to be feasible.Five FBG sensors were set along the blade length in order to measure distributed strain.However,environmental or measurement noise may cover the structural signals.Dual-tree complex wavelet transform(DT-CWT)is suggested to wipe off the noise.The experimental studies indicate that the tested strain fluctuate distinctly as one of the blades is broken.The rotation period is about 1 s at the given working condition.However,the period is about 0.3 s if all the wind blades are in good conditions.Therefore,strain monitoring by FBG sensors could predict damage of a wind turbine blade system.Moreover,the studies indicate that monitoring of one blade is adequate to diagnose the status of a wind generator.

Development of a Remotely Controlled Testing Platform with Low-drag Air-ventilated Hull

This paper addresses the development and testing of a remotely controlled boat platform with an innovative air-ventilated hull. The application of air cavities on the underside of ship hulls is a promising means for reducing hydrodynamic drag and pollutant emissions and increasing marine transportation efficiency. Despite this concept＇s potential, design optimization and high-performance operation of novel air-cavity ships remain a challenging problem. Hull construction and sensor instrumentation of the model-scale air-cavity boat is described in the paper. The modular structure of the hull allows for easy modifications, and an electric propulsion unit enables self-propelled operation. The boat is controlled remotely via a radio transmission system. Results of initial tests are reported, including thrust, speed, and airflow rate in several loading conditions. The constructed platform can be used for optimizing air-cavity systems and testing other innovative hull designs. This system can be also developed into a high-performance unmanned boat.

Structure buckling and non-probabilistic reliability analysis of supercavitating vehicles

To perform structure buckling and reliability analysis on supercavitating vehicles with high velocity in the submarine,supercavitating vehicles were simplified as variable cross section beam firstly.Then structural buckling analysis of supercavitating vehicles with or without engine thrust was conducted,and the structural buckling safety margin equation of supercavitating vehicles was established.The indefinite information was described by interval set and the structure reliability analysis was performed by using non-probabilistic reliability method.Considering interval variables as random variables which satisfy uniform distribution,the Monte-Carlo method was used to calculate the non-probabilistic failure degree.Numerical examples of supercavitating vehicles were presented.Under different ratios of base diameter to cavitator diameter,the change tendency of non-probabilistic failure degree of structural buckling of supercavitating vehicles with or without engine thrust was studied along with the variety of speed.

Role of Wind Power in Energy Development in China

In recent years,China has made significant achievements in optimizing its energy structure and tapping into renewable energy.Wind power,in particular,has been doubled in its development year by year between 2005-2009.However,wind power develops too fast,which is not harmonious with the power system,the industry structure and the policy mechanism.Therefore,it is necessary to find the fundamental causes for the issue.Based on the inherent features and practical issues of wind power development in China,the role of wind power in energy development is put forward through probing logically into three perspectives,i.e.energy utilization,energy development and the ultimate objectives of wind power development.The current wind power development should be grounded on the improvement of wind power industrialization system,the smart grid and the research on new energy storage technology so as to lay firm foundations for large-scale development of wind power in the future.

Feasibility of developing composite action between concrete and cold-formed steel beam

Cold-formed steel structures are steel structure products constructed from sheets or coils using cold rolling, press brake or bending brake method. These structures are extensively employed in building construction industry due to their light mass, ductility by economic cold forming operations, favorable strength-to-mass ratio and other factors. The utilization of cold formed steel sections with concrete as composite can hugely reduce the construction cost. However, the use of cold formed steel members in composite concrete beams has been very limited. A comprehensive review of developments in composite beam with cold formed steel sections was introduced. It was revealed that employing cold-formed steel channel section to replace reinforcement bars in conventional reinforced concrete beam results in a significant cost reduction without reducing strength capacity. The use of composite beam consisting of cold-formed steel open or close box and filled concrete could also reduce construction cost. Lighter composite girder for bridges with cold-formed steel of U section was introduced. Moreover, types of shear connectors to provide composite action between cold-formed steel beam and concrete slab were presented. However, further studies to investigate the effects of metal decking on the behavior of composite beam with cold-formed steel section and introduction of ductile shear connectors were recommended.

Assessing Anthropogenic Pressure and Its Impact on Hippophae salicifolia Pockets in Central Himalaya,Uttarakhand

Natural habitat ofHippophae salicifolia in Central Himalaya is continuously being degraded due to habitat destruction and harvesting. Although logging is prohibited, habitat destruction has increased because of regular road construction, repairing and broadening activities. In addition, Hippophae resources are continuously being harvested by lopping （both partial and complete） for fuelwood, fodder and fruits in higher Himalayan region. This paper presents a detailed analysis of relationship between density, demographic structure, and harvesting of H. salicifolia growing pockets in the five major valleys （Gangotri, Yamunotri, Niti, Mana and Bhyundhar） of Uttarakhand in Central Himalaya, India. A total of 12o quadrats were laid randomly to study population structure, regeneration, sex ratio and lopping using quadrats of lOO m2 （a4 in each valley） in Hippophae growing patches. Our study shows that the density, size distribution, and regeneration of Hippophae vary considerably among the major valleys. Trees in the Yamunotri valley have the highest density of large trees but the lowest density of seedlings. In contrast, there are few large trees but many seedlings in the Mana valley. The number and size of lopped trees also varied among the valleys. Lopping was greatest in Bhyundhar （11.4%） and Yamunotri （19.7%） and least in Niti （3.9%）. The size of lopped trees differed substantially as well. In Bhyundhar, the largest trees were taken while saplings were taken in Yamunotri. Our study revealed that unsustainable harvesting from plants for fuel, fencing and fruits along with road broadening activities in Central Himalaya are the main cause ofhabitat destruction. Our research highlights the urgent need for in-situ and ex-situ conservation of Hippophae salicifolia so that it＇s potential can be harnessed sustainably by rural hill societies for their socio-economic development.

Numerical Analysis of a Gravity Substructure for 5 MW Offshore Wind Turbines Due to Soil Conditions

In order to increase the gross generation of wind turbines, the size of a tower and a rotor-nacelle becomes larger. In other words, the substructure for offshore wind turbines is strongly influenced by the effect of wave forces as the size of substructure increases. In addition, since a large offshore wind turbine has a heavy dead load, the reaction forces on the substructure become severe, thus very firm foundations should be required. Therefore, the dynamic soil-structure interaction has to be fully considered and the wave forces acting on substructure accurately calculated. In the present study, ANSYS AQWA is used to evaluate the wave forces. Moreover, the substructure method is applied to evaluate the effect of soil-structure interaction. Using the wave forces and the stiffness and damping matrices obtained from this study, the structural analysis of the gravity substructure is carried out through ANSYS mechanical. The structural behaviors of the strength and deformation are evaluated to investigate an ultimate structural safety and serviceability of gravity substructure for various soil conditions. Also, the modal analysis is carried out to investigate the resonance between the wind turbine and the gravity substructure.

Moment-Rotation Characteristics for Flexible Beam-to-Column Steel Joint Exposed to Fire

Analytical models used to describe behaviour of steel frame loadbearing structures in fully developed fire usually do not allow for reduced joint stiffness due to increased member temperature. Joints previously designed as nominally rigid tend to become flexible in fire situation, with degree of flexibility increasing during fire development. Reliable analysis of this phenomenon and its influence on the redistribution of internal forces result in the need for developing appropriate characteristics, describing relationship between bending moment applied to the joint and joint rotation. Characteristics of such type, specified for fire conditions, depend on steel temperature, in the current work, the authors propose a practical approach to develop such characteristics, based on the knowledge of analogous characteristic prepared for persistent design situation. The developed technique does not require to generalize the classical component method to the case of fire, which may be difficult in practical situations. The proposed computational algorithm has been tested on an example of a typical beam-to-column joint.

Stand-Alone Wind Power System Operating with Different Storage Structures

This paper deals with control method related to a wind system operating in stand-alone applications. The stand-alone wind system is composed of three energy transfer subsystems： wind generator subsystem （wind turbine and electrical generator）, energy storage subsystem, respectively, specific local network subsystem （controlled loads）. This wind power system performs in the same time the maximization of wind energy conversion and the power balance between produced and required power. Three structures of the energy storage subsystem, based on buffer battery operation and/or capacitor voltage control, are discussed. The simulation results show that the proposed stand-alone wind power system ensures a good management of the local energy request. The design of the structures is analyzed in Matlab/Simulink environment, using PowerSim toolbox.