A low-frequency debris flow took place in the north coastal range of Venezuela on Dec. 16, 1999, and scientists all over the world paid attention to this catastrophe. Four characteristics of low-frequency debris hazar...A low-frequency debris flow took place in the north coastal range of Venezuela on Dec. 16, 1999, and scientists all over the world paid attention to this catastrophe. Four characteristics of low-frequency debris hazard are discussed: long return period and extreme catastrophe, special rare triggering factors, difficulty in distinguishing and a series of small hazards subsequent to the catastrophe. Different measures, such as preventing, forecast - warning, engineering, can be used for mitigating and controlling the catastrophe. In engineering practice, it is a key that large silt-trap dams are used to control rare large debris flow. A kind of low dam with cheap cost can be used to replace high dam in developing countries. A planning for controlling debris flow hazard in Cerro Grande stream of Venezuela is presented at the end of this paper.展开更多
Cydia pomonella （Linnaeus） is a fruit decay pests attacking apples, pears and other fruits, and it is an important quarantine pests in China. In recent years, the momentum of the eastward aggression of the insect in...Cydia pomonella （Linnaeus） is a fruit decay pests attacking apples, pears and other fruits, and it is an important quarantine pests in China. In recent years, the momentum of the eastward aggression of the insect in our country was more and more serious, and the harm degree was deepening. If Cydia pomonella （Linnaeus） is introduced, fruit production will be significantly affected in Hebei Province. The damage characteristics, morphological characteristics and life habit of Cydia pomonella （Linnaeus） were reviewed, and the control measures were proposed, in order to provide technical support for promoting the sound development of fruit industries in Hebei province.展开更多
文摘A low-frequency debris flow took place in the north coastal range of Venezuela on Dec. 16, 1999, and scientists all over the world paid attention to this catastrophe. Four characteristics of low-frequency debris hazard are discussed: long return period and extreme catastrophe, special rare triggering factors, difficulty in distinguishing and a series of small hazards subsequent to the catastrophe. Different measures, such as preventing, forecast - warning, engineering, can be used for mitigating and controlling the catastrophe. In engineering practice, it is a key that large silt-trap dams are used to control rare large debris flow. A kind of low dam with cheap cost can be used to replace high dam in developing countries. A planning for controlling debris flow hazard in Cerro Grande stream of Venezuela is presented at the end of this paper.
文摘Cydia pomonella （Linnaeus） is a fruit decay pests attacking apples, pears and other fruits, and it is an important quarantine pests in China. In recent years, the momentum of the eastward aggression of the insect in our country was more and more serious, and the harm degree was deepening. If Cydia pomonella （Linnaeus） is introduced, fruit production will be significantly affected in Hebei Province. The damage characteristics, morphological characteristics and life habit of Cydia pomonella （Linnaeus） were reviewed, and the control measures were proposed, in order to provide technical support for promoting the sound development of fruit industries in Hebei province.
