【正文】 數(shù)（單位/千萬）模型 2模型 1圖 4 模型一、二的散點圖 由圖 4 可知 ，在二胎政策下，到 2020 年我國的總?cè)丝诩s為 億，與模型一相比，我國總?cè)丝诘脑鲩L幅度為 1%；到 2030 年我國總?cè)丝诩s為 億，我國總?cè)丝诘脑鲩L幅度為 2%，到 2040 年我國總?cè)丝诩s為 億，我國總?cè)丝诘脑鲩L幅度為 %；到 2050 年我國的總?cè)丝诩s為 億，我國總?cè)丝诘脑鲩L幅度為 %． 新鄉(xiāng)學(xué)院本科畢業(yè)論文（設(shè)計） 14 模型三：基于模型一的 Leslie 人口結(jié)構(gòu) 矩陣 Leslie 種群模型的介紹 Leslie模型屬于一種以年齡和性別為基礎(chǔ)的離散矩陣模型，能夠克服 Logistic模型只能在總 量上預(yù)測的缺陷，特別是其考慮年齡結(jié)構(gòu)，所以其顯得比 Logistic等其他群體的模型更具有優(yōu)越性 [12]． 我們將群體按年齡的大小等間隔的分成 n 個組，討論其在不同時間年齡的分布，對時間加以離散化，其間隔也必須與年齡組的間隔相同． 設(shè)某生物種群的最大生存年齡為 l（年），我們將其按年齡的大小區(qū)間 ? ?l，0 分為 n 等分，可得到 n 個年齡間隔為 nl 的年齡組，即有 1[ , ], 1, 2 , , .iil l i nnn? ? 對于第 i 個年齡組 ?????? ? lnilni ,1,設(shè)其存活率為 is ，生育率為 ib ，一個年齡組的變化時間為 1，則有當(dāng)時間從 1?t 到 t 的過程中，顯然有 ? ? ? ?? ? ? ?111111 , 2 , ,niiii i iz t b z tz t s z t i n???? ?????? ? ??? ，． ）（ 9 其中若計矩陣 L 為 。c/(1+(c/)*exp(5*d))=39。 [c ， d]=solve(39。) b0=[ ， ]。 [b， r， j]=nlinfit(t， x， fun， b0)。) 附錄三：函數(shù)圖像 t=2022:1:2050?；厥状髮W(xué)生活，新鄉(xiāng)學(xué)院承載了我最美年華里的四個春翡夏翠 秋金冬銀，有過歡笑也曾留下遺憾，但慶幸的是，此時此刻我們還能聚首一起暢想未來。 新鄉(xiāng)學(xué)院本科畢業(yè)論文（設(shè)計） 25 請您刪除一下內(nèi)容， O(∩ _∩ )O 謝謝?。。?Many people have the same mixed feelings when planning a trip during Golden Week. With heaps of time, the sevenday Chinese 請您刪除一下內(nèi)容， O(∩ _∩ )O 謝謝?。?！ National Day holiday could be the best occasion to enjoy a destination. However, it can also be the easiest way to ruin how you feel about a place and you may bee more fatigued after the holiday, due to battling the large crowds. During peak season, a dream about a place can turn to nightmare without careful planning, especially if you travel with children and older people. As most Chinese people will take the holiday to visit domestic tourist destinations, crowds and busy traffic are inevitable at most places. Also to be expected are increasing transport and acmodation prices, with the possibility that there will be no rooms available. It is also mon that you39。s Day! in shops, hotels and restaurants. But few young women will mark the festival with their boyfriends, or take part in traditional activities to pray for cleverness. A largescale of exhibition on the Silk Road opened to the public in the National Museum on Thursday. The exhibition displays more than 400 treasures from Shaanxi province, Gansu province and 14 other regions. It is largest scale exhibition that shows the history of the Silk Road in recent years. As APEC is going on in Beijing, the exhibit aims to show the world this brilliant section of history. The Silk Road is a series of trade and cultural transmission routes that were central to cultural interaction through regions of the Asian continent. It connected the West and East by linking traders, merchants, pilgrims, monks, soldiers, nomads, and urban dwellers from China and India to the Mediterranean Sea during various periods of time. I met my dear hubby in 2022 the second year I was in my school and it was the first year when he came here. We became colleagues. And there was nothing special happening during that year. He was just a kind and humble brother graduated from the same college as me. But we did not know each other till he became my colleague and his office desk was just in front of me. There was only a glass between us. So actually we could see each other when we both look up. But it is not the main reason that really draws us close. How we bee close to each other was something seems quite natural. We went out to play badminton with other colleagues and we sometimes chatted for a while. He is a man of few words but somehow sometimes will say something really humorous. Then one day, to my great surprise, I found a pot of beautiful flower on my desk. It was just the flower I had talked about with my colleague the other day, and I thought it was her who put the flower there. But the truth is not. It was the humble guy sitting in front of me. He just simply said ,”well, I caught sight of this flower and thought that it’s beautiful and you may like it”. I wonder why I was moved because of these simple words and present. Maybe it is the sincerity and the true self that impress me. I thanked him and some colleagues walked past my desk would appreciate the beautiful flower and they noticed that something romance happened there. Then later on, there were some little surprises once in a while. Once, there was something wrong with my drawer and I had plained about it unconsciously. And he fixed it for me. Then the other day, he placed several pink diamond roses beside the flower with a piece of paper saying” I love you more than I can say! Diamond stands for marriage, rose stand for love. I hope you are mine, bee my wife. You are the only girl who I really want to spend the rest of my life to stand by.” Although there were some grammar errors but I got what he meant. He meant so clear and so direct. And actually, I accepted him some days earlier. I was just waiting for him to break the ice. So finally, the mon interests and the mon understanding brought us together. Some people say the relationship and the feeling will change after getting hitched. You will find that love is no longer strong and there is always lack of passion and what’s worse you may find out many bad habits of your partner, which never appear when you are first in love before the marriage. It seems that many faults turn up after you truly living together and see each other’s face the moment you open your eyes in the early morning. But after almost 4 years from now, I do not feel any negative change in our relationship. During all these years, we know each other better and we bee more tolerant about each other and I realize that if you really love a person you will accept his imperfect. And what is the qualification of a good husband? Once I was chatting with my colleague about this issue. And one of the qualifications I thought was that he must be a good cook. But to my sur