ABSTRACT
The taro harvesting process is affected by a complex system composed of particle mechanics system and multi-body dynamics system. The discrete element method(DEM) can effectively solve the nonlinear problem of the interaction between harvesting components and working materials. Therefore, the discrete element model of taro tiller plants is of great importance for taro harvesting. This paper proposes a simulation method to establish a discrete element flexible plant model and dynamic clamping and pulling process of taro tiller plant. Discrete Element models of taro corm and flexible tiller petiole and leaf were established using DEM method, and the discrete element flexible model of the taro plant was established. Taro clamping and pulling force testing platform was designed and built. The single factor and Plackett-Burman experiments were used to determine the simulation parameters and optimize the taro plant model by taking the correlation coefficient of clamping force and correlation coefficient of pulling force collected from the simulation and the bench experiment as the experiment index. The parameter calibration results of discrete element model of taro plant are as follows: petiole-petiole method/tangential contact stiffness was 8.15×109 N·m-3, and normal/tangential critical stress was 6.65×106 Pa. The contact stiffness of pseudostem- corm method was 1.22×109 N·m-3, the critical stress of normal/tangential was 1.18×105 Pa, and the energy of soil surface was 4.15×106J·m-3. When the pulling speed is 0.1, 0.2, 0.3, 0.4 and 0.5 m·s-1, the correlation coefficients between the simulation experiment and the bench experiment are 0.812, 0.850, 0.770, 0.697 and 0.652, respectively. The average value of correlation coefficient is 0.756, indicating that the simulated discrete element plant model is close to the real plant model. The discrete element model of taro plant established in this paper has high reliability. The final purpose of this paper is to provide a model reference for the design and optimization of taro harvester by discrete element method.
ABSTRACT
This paper introduced the legislative development of community benefits system of nonprofit hospitals at federal level in the United States,as well as state legislatures in this regard. Based on America's experiences, an analysis was made on the "community benefits and health promotion model", which refers to community health needs assessment, health promotion programs, program implementation, supervision and appraisal. Thus the authors put forward inspirations for the social responsibility system development of public hospitals in China as follows. This refers to the establishment of hospitals' social responsibility system; development of community health promotion planning based on health needs;and establishment of social responsibility information disclosure system for fulfillment of their social responsibilities.
ABSTRACT
Modernization of theories of traditional Chinese medicine (TCM) is a key issue for the development of Chinese medicine. As TCM concepts are too vague and lack precise definition, it is difficult to test those theories by modern technologies. Methods of TCM classification are not accepted by Western medicine so far. Because of the diversity and complexity of Chinese herbal medicines, the molecules of Chinese herbal medicines are difficult to be separated, and efficacy is difficult to be verified and classified by biological and chemical methods. In order to verify the scientificity of TCM classification, molecular properties can be studied by their spectrum, and be combined with latent semantic analysis technology and weighting method which are widely used in the Internet search engine. 48 Chinese herbal medicines belonging to four kinds of Chinese herbal medicines:nourishing yin, tonifying yang, invigorating qi, and enriching blood, are analyzed through NIRS, and the results are almost the same as the TCM classification.
