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- The existence of peoriodic solutions is given first, then the global attractivity of coupled system of semilinear parabolic equations is investigated by using upper and lower solutions and through principal eigenvalue analysis. 首先给出周期解的存在性，再用有序上下解及主特征值分析方法研究耦合半线性抛物方程组周期解的全局吸引性。
- My wages are the principal source of my income. 薪金是我收入的主要来源。
- The principal shareholder ask for a meeting. 主要股东们要求召开会议。
- The agent spoke on behalf of his principal. 代理人代表他的委托人说话。
- Keys are available on application to the principal. 向校长申请就可得到钥匙。
- She's been downgraded (from principal) to deputy. 她已(从校长)降为副校长。
- Our principal problem is lack of time. 我们的主要问题就是缺少时间。
- She drank in every word of the principal's lecture. 她全神贯注地听校长演讲的字字句句。
- John informed the principal against Paul. 约翰向校长告发了保罗。
- The central or principal vein of a leaf. 中脉中心的或主要的叶脉
- The principal discouraged unexcused absences. 校长不准无故缺课。
- Rubber is the country's principal export. 橡胶制品是该国主要的出口产品。
- The principal has a very tight schedule. 校长的日程表排得满满的。
- Our school gave a reception to our new principal. 我们学校为新校长举行了欢迎会。
- The principal knew all the students individually. 校长认识每个学生。
- Drinking is a principal cause of traffic accidents. 酗酒是交通事故的主要原因。
- The school principal read the honor roll list. 校长宣读优秀生名单。
- The principal dwelt on traffic safety in his talk. 校长没完没了地谈论交通安全问题。
- My principal concern is my family's welfare. 我至为关心的是我一家的幸福。
- principal eigenvalues 主特征值
