程控滤波器制作与探讨

系统以FPGA器件和微处理器为核心构成,由程控放大器、参数可调滤波器、简易幅频特性测试仪和控制显示单元四部分组成。其中程控放大器增益为(0~60)dB,10 dB步进;在单片FPGA器件中集成了低通、高通和椭圆三种数字滤波器;滤波器截止频率和放大器放大倍数可通过4×4键盘设置并在液晶上显示;幅频特性测试仪可绘出所测系统的幅频特性曲线。整个系统设计方案先进,精度高,各项指标均满足设计要求。     

A model of dynamic conflict in ethnocracies

We model an infinitely repeated Tullock contest, over the sharing of some given resource, between two ethnic groups. The resource is allocated by a composite state institution according to relative ethnic control; hence the ethnic groups contest the extent of institutional ethnic bias. The contest yields the per-period relative influence over institutions, which partly spills over into the next period, by affecting relative conflict efficiency. Our model generates non-monotone evolution of both conflict and distribution. Results suggest that external interventions, when effective in reducing current conflict and protecting weaker groups, may end up sowing the seeds of greater future conflict.     

第19届物理竞赛对我院物理实验教学的启示

通过对北京市第19届非物理类专业大学生物理竞赛,我院和其他几个重点院校实验题得分的对比分析,尤其是实验能力得分率的详细分析,对大学物理实验教学和相关教学改革提供思考和借鉴。     

浅谈数学建模与创新能力的培养

本文从数学建模教学和数学建模竞赛的角度论述了数学建模对学生创新能力的培养具有重要的作用。     

United Nations Security Council reform and the dilemmas of African continental integration

This article analyses the disunity among African states in terms of United Nations Security Council (UNSC) reform, and attributes it to the contest between South Africa and Nigeria. These two countries have been locked in a hegemonic contest for continental domination. To this end, the article notes that African unity, not in terms of protocol but on the basis of principles and cooperation, is sacrosanct in order for the African Union to make a significant contribution to the reform of the UNSC. It is asserted that the contest between South Africa and Nigeria has been symbolised by the continental leadership aspirations of the heads of state of both countries, and recommends that it be tamed through forging diplomatic and strategic partnerships between the ruling parties of these two countries. The influence of external actors on the African countries, particularly that of France, is underscored as a contributing factor in stalling the debate on the UNSC reform. It recommends that South Africa use its strategic partnership within the association of Brazil, Russia, India, China and South Africa (BRICS), particularly Russia and China as permanent members of the UNSC, to influence the realisation of the reform debate.     

一类军事竞争系统的非线性分析

应用非线性系统的定性理论方法,对一类军事竞争系统进行了定性分析,研究了系统平衡点的性态,证明了系统在全平面不存在闭轨线。