培养就业能力是从改善劳动力供给状况角度解决就业问题的一种手段,通过就业能力的提高使人们可以面对不断变化的社会环境和就业环境。由于就业能力被学界认定为具有多维度、多元化的特点(Fugate et al.2004),因此在众多的研究中找到与...培养就业能力是从改善劳动力供给状况角度解决就业问题的一种手段,通过就业能力的提高使人们可以面对不断变化的社会环境和就业环境。由于就业能力被学界认定为具有多维度、多元化的特点(Fugate et al.2004),因此在众多的研究中找到与现实环境相匹配的理论才有可能指导实践。本文通过对就业能力的使用主体、就业能力动态性特征、环境对就业能力的制约进行理论综述,然后借鉴其他国家就业能力培养方面的经验,最后为高等院校学生就业能力培养提出了对策建议。展开更多
The three-point bending experiments were applied to investigating effects of loading rates on fracture toughness of Huanglong limestone. The fracture toughness of Huanglong limestone was measured over a wide range of ...The three-point bending experiments were applied to investigating effects of loading rates on fracture toughness of Huanglong limestone. The fracture toughness of Huanglong limestone was measured over a wide range of loading rates from 9 × 10-4 to 1.537 MPa.m1/2/s. According to the approximate relationship between static and dynamic fracture toughness of Huanglong limestone, relationship between the growth velocity of crack and dynamic fracture toughness was obtained. The main conclusions are summarized as follows. （1） When the loading rate is higher than 0.027 MPa-ml/2/s, the fracture toughness of Huanglong limestone increases markedly with increasing loading rate. However, when loading rate is lower than 0.027 MPa-ml/2/s, fracture toughness slightly increases with an increase in loading rate. （2） It is found from experimental results that fracture toughness is linearly proportional to the logarithmic expression of loading rate. （3） For Huanglong limestone, when the growth velocity of crack is lower than 100 m/s, the energy release rate slightly decreases with increasing the growth velocity of crack. However, when the growth velocity of crack is higher than 1 000 m/s, the energy release rate dramatically decreases with an increase in the crack growth velocity.展开更多
Reliability tolerance design of electromagnetic relay during its design period plays an essential role in guaranteeing the consistencies of reliability and output characteristic. The reliability tolerance design can e...Reliability tolerance design of electromagnetic relay during its design period plays an essential role in guaranteeing the consistencies of reliability and output characteristic. The reliability tolerance design can ensure that the products would work well under the influence of disturbing factors (including internal interference, external interference, and machining dispersion). Com- pared with static characteristic, dynamic characteristic of electromagnetic relay can describe its operating process better. This article researches influence of the three kinds of disturbing factors on the dynamic characteristic of electromagnetic relay based on calculating dynamic characteristic. Then, the dynamic reliability tolerance design method of electromagnetic relay is discussed considering three kinds of disturbing factors. Conclusions reached can help to assure the reliability of electromagnetic relay from the beginning of design.展开更多
An accurate seal forces model is the foundation to analyze the rotor-seal systems. In this paper, the Navier-Stokes equation and energy equation are solved to simulate the interior flow field in the labyrinth seal gap...An accurate seal forces model is the foundation to analyze the rotor-seal systems. In this paper, the Navier-Stokes equation and energy equation are solved to simulate the interior flow field in the labyrinth seal gap. The leakage rate is compared with the experimental results in the literatures. The ：4maximum error is 4% , which proves that the method of employing CFD to simulate the interior flow field of labyrinth seal gap is reliable. Based on this, the interior flow field and fluid exciting force of stage teeth labyrinth seal are studied. By coupling with the Muszynska model, the method of defining the experience loss parameters in Muszynska model is proposed. The results indicate that the experience parameters obtained by the proposed method can depict the nonlinear exciting force of labyrinth seal better.展开更多
In order to investigate the behavior of buildings and engineering structures during earthquakes, based on the data of seismic observation devices mounted on constructions with typical characteristics, results of inves...In order to investigate the behavior of buildings and engineering structures during earthquakes, based on the data of seismic observation devices mounted on constructions with typical characteristics, results of investigating the change of mechanical properties of building structural system over time and the results of examination of structural rigidity and safety change over time, depending on the dynamic characteristics of the building, determined by experimental investigations made at intervals are mentioned in this article. In addition, evaluation of earthquake acceleration acting on structures due to earthquake-induced damage characteristics of buildings and engineering constructions which are made earthquake resistant is also included here.展开更多
Based on the short-bearing model, the stability of a rigid Jeffcott rotor system is studied in a relatively wide parameter range by using Poincaré maps and the numerical integration method. The results of the cal...Based on the short-bearing model, the stability of a rigid Jeffcott rotor system is studied in a relatively wide parameter range by using Poincaré maps and the numerical integration method. The results of the calculation show that the period doubling bifurcation, quasi-periodic and chaotic motions may occur. In some typical parameter regions, the bifurcation diagrams, phase portrait, Poincaré maps and the frequency spectrums of the system are acquired with the numerical integration method. They demonstrate some motion state of the system. The fractal dimension concept is used to determine whether the system is in a state of chaotic motion. The analysis result of this paper provides the theoretical basis for qualitatively controlling the stable operating states of the rotors.展开更多
文摘培养就业能力是从改善劳动力供给状况角度解决就业问题的一种手段,通过就业能力的提高使人们可以面对不断变化的社会环境和就业环境。由于就业能力被学界认定为具有多维度、多元化的特点(Fugate et al.2004),因此在众多的研究中找到与现实环境相匹配的理论才有可能指导实践。本文通过对就业能力的使用主体、就业能力动态性特征、环境对就业能力的制约进行理论综述,然后借鉴其他国家就业能力培养方面的经验,最后为高等院校学生就业能力培养提出了对策建议。
基金Projects(50490275, 50621403, 50778184) supported by the National Natural Science Foundation of ChinaProject(NCET-07-0911) supported by Program of New Century Talents of Ministry of EducationProject(CSTC, 2009BA4046) supported by the Natural Science Foundation of CQ CSTC
文摘The three-point bending experiments were applied to investigating effects of loading rates on fracture toughness of Huanglong limestone. The fracture toughness of Huanglong limestone was measured over a wide range of loading rates from 9 × 10-4 to 1.537 MPa.m1/2/s. According to the approximate relationship between static and dynamic fracture toughness of Huanglong limestone, relationship between the growth velocity of crack and dynamic fracture toughness was obtained. The main conclusions are summarized as follows. （1） When the loading rate is higher than 0.027 MPa-ml/2/s, the fracture toughness of Huanglong limestone increases markedly with increasing loading rate. However, when loading rate is lower than 0.027 MPa-ml/2/s, fracture toughness slightly increases with an increase in loading rate. （2） It is found from experimental results that fracture toughness is linearly proportional to the logarithmic expression of loading rate. （3） For Huanglong limestone, when the growth velocity of crack is lower than 100 m/s, the energy release rate slightly decreases with increasing the growth velocity of crack. However, when the growth velocity of crack is higher than 1 000 m/s, the energy release rate dramatically decreases with an increase in the crack growth velocity.
基金Project (No. LRB05-002) supported by the Heilongjiang Postdoc-toral Fund, China
文摘Reliability tolerance design of electromagnetic relay during its design period plays an essential role in guaranteeing the consistencies of reliability and output characteristic. The reliability tolerance design can ensure that the products would work well under the influence of disturbing factors (including internal interference, external interference, and machining dispersion). Com- pared with static characteristic, dynamic characteristic of electromagnetic relay can describe its operating process better. This article researches influence of the three kinds of disturbing factors on the dynamic characteristic of electromagnetic relay based on calculating dynamic characteristic. Then, the dynamic reliability tolerance design method of electromagnetic relay is discussed considering three kinds of disturbing factors. Conclusions reached can help to assure the reliability of electromagnetic relay from the beginning of design.
基金the National Natural Science Foundation of China (Grant No. 10632040)
文摘An accurate seal forces model is the foundation to analyze the rotor-seal systems. In this paper, the Navier-Stokes equation and energy equation are solved to simulate the interior flow field in the labyrinth seal gap. The leakage rate is compared with the experimental results in the literatures. The ：4maximum error is 4% , which proves that the method of employing CFD to simulate the interior flow field of labyrinth seal gap is reliable. Based on this, the interior flow field and fluid exciting force of stage teeth labyrinth seal are studied. By coupling with the Muszynska model, the method of defining the experience loss parameters in Muszynska model is proposed. The results indicate that the experience parameters obtained by the proposed method can depict the nonlinear exciting force of labyrinth seal better.
文摘In order to investigate the behavior of buildings and engineering structures during earthquakes, based on the data of seismic observation devices mounted on constructions with typical characteristics, results of investigating the change of mechanical properties of building structural system over time and the results of examination of structural rigidity and safety change over time, depending on the dynamic characteristics of the building, determined by experimental investigations made at intervals are mentioned in this article. In addition, evaluation of earthquake acceleration acting on structures due to earthquake-induced damage characteristics of buildings and engineering constructions which are made earthquake resistant is also included here.
文摘Based on the short-bearing model, the stability of a rigid Jeffcott rotor system is studied in a relatively wide parameter range by using Poincaré maps and the numerical integration method. The results of the calculation show that the period doubling bifurcation, quasi-periodic and chaotic motions may occur. In some typical parameter regions, the bifurcation diagrams, phase portrait, Poincaré maps and the frequency spectrums of the system are acquired with the numerical integration method. They demonstrate some motion state of the system. The fractal dimension concept is used to determine whether the system is in a state of chaotic motion. The analysis result of this paper provides the theoretical basis for qualitatively controlling the stable operating states of the rotors.
