R0代数性质新探

在R0代数中定义了Boole元，得出Boole元的性质以及有限R0代数中Boole元的分布规律；研究了R0代数M的滤子和R0代数M作为有界分配格(记这个有界分配格为L(M))的滤子之间的关系，得出结论：L(M)的极小素滤子以及L(M)的Stone滤子都是M的滤子，并给出一个具体例子说明L(M)的滤子一般不必是M的滤子，比文献[3]中有关结论更进一步。     

某些问题的圆背景(高一、高二、高三)——用直线与圆有公共点的位置关系式解题

若直线肘干切＋C—0（A、B、C6R且A、＋t’一9—0与圆／＋y’一1有公共点（。，y）， B不同时为霉）与圆灯10》“十（）一yo》一厂什刚巾①很三二二二上】＜卫， tr 0）右公扛占（工，们，则）16十16 人了下豆又因为 t ＞ 0，所以 t ＜l牛 2尼 特别地，当x。一人一0时坝u。。、．．＿＿I＿。，、M ，、。。—，。。。。、uv。J·。。所以z一J；b。一1十2y2 IC－。。 六六＼＜ r②例 2术函数八。）一 2／5；z－－－－－－－－－ram－－－－－－－－m科 ml〕IFMc＄．＆A＊lp＄w解…     

关于一类具有垂直传染与治疗SIR模型产生后向分支的研究

考虑了有限治疗资源和垂直传染的一类传染病模型,当染病个体数量小于某确定值时,治疗康复人数与染病个体数成比例;当染病个体数量大于某确定值时,治疗康复人数是确定常数值.确定了模型的基本再生数R0.在一定条件下,当R0〉1时,地方病平衡点E＊是渐进稳定的;当R0〈1时,后向分支就产生了.     

有限生成投射模及其自同态环的矩阵方法

设R是整环,Mn（R）是R上的n阶矩阵环。文中借助于矩阵计算方法,证明了轶为n的投射R-模P的自同态环可以表示为S=Y TMm（R）X,其中（X,Y）为P的一个m-基耦,还证明了P是自由R-模当且仅当R n＊P作为Mn（R）-模是循环模,当且仅当R n＊P≠ ∪（Rn＊P）Mi,其中Mi取遍S的极大左理想。     

β——环的一个结论

R是局部环且是β—环当且仅当 R是特殊准素环或 R是强准素环或 R是秩为 1的离散赋值环。证　充分性 :如果 R是特殊准素环或 R是秩为 1的离散赋值环 ,则 R是局部环且是主理想环从而是 β—环。如果 R是强准素环 ,设 M是 R的唯一的素理想 ,A是 R的非零真理想 ,则 M2 =( 0 ) ,A M。如果 A=M,则R/A是域从而是主理想环。如果 A M,设 B是满足 A B M的任一理想 ,则由 M2 =( 0 )可知 M可看成域 k=R/M上的向量空间 ,而 A,B可看成是 M的子空间 ,又显然 1≤ dimk A相似文献   

具有变化潜伏期的水源性疾病模型稳定性分析

建立了一类具有变化潜伏期的水源性疾病数学模型,得到了水源性疾病流行的阈值R0（基本再生数）.利用LaSalle不变集原理,通过构造新的Liapunov函数证明了平衡点的全局稳定性：当R0≤1时,系统的无病平衡点p0是全局渐近稳定的;当R0＞1时,系统的地方病平衡点p＊是全局渐近稳定的.最后利用数值模拟说明结论的正确性.     

余星n模的推广

如果一个模余自小和无穷拟内射称其为余星无穷模.研究了其性质及等价刻画.当一个模为余星无穷模时,函子HomRU（-,U）在Copres∞（U）中正合.一个模是余星无穷模当且仅当U余自小,对任意的正合列0→M→UI→N→0满足M∈Copres∞（U）且I是一个集合,N∈Copres∞（U）等价于ExtR1（N,U）→Ext1R（UI,U）是一个单同态当且仅当U余自小并且对于任意的正合列0→L→M→N→0满足L,N∈Copres∞（U）,N∈Copres∞（U）等价于导出的列0→Δ（N）→Δ（M）→Δ（L）→0是正合的当且仅当U通过函子ΔUS和ΔRU导出了子范畴⊥US和Copres∞（U）之间的对偶.并且证明了一个模为余星n模当且仅当它是余星无穷模且Copres∞（U）=Copresn（U）.     

半环R上的L-Fuzzy左(右)理想及性质

定义了半环R上的L Fuzzy左 (右 )理想 ,讨论了其上的一些性质     

环上的Fuzzy同余

定义了环上的Fuzzy同余关系，讨论了带有Fuzzy同余关系的环R的性质．证明了：如果R是一个带有Fuzzy同余关系的环，其Fuzzy同余关系的核是R的一个Fuzzy理想；并给出了带有Fuzzy同余关系的环的同态性质．     

我

我就是 0,I就是我。 那么,英语中“我的”又是怎么表示的呢?MY.M—Y. 嗅,应该Z是:“Do yoUF6ffi6ffib6r Ji6?”J～旧＊6＊＊e卜否u切_＊＊切＊M 坝＊fe口 丑色 ＊00.回括、拙男我@乐乐 @艺蓝     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.