【正文】 2. . 新鄉(xiāng)學(xué)院本科畢業(yè)論文（設(shè)計） 22 附 錄 附錄一：擬合函數(shù) X（ t） t=0:30。s population one: according to the data,the paper carries on the forecast to the amount and growth rate of future population with the Logistic model. we can make Chinese population prediction from 2022 to 2050 . under the basic of model one,Model two is to find out the growth pattern after releasing twochild policy 20222050 in the relationship that the annual mortality rate is stable and the birth rate is 1a? times of model one (‘a(chǎn) ’refers to the proportion of the population that have the willingness to have a second child) with excel iteration. model three and four are the use of Leslie model,according to the result of model 1,2. Implement twochild policy for the future development of the population outweigh the disadvantages. Key words: Logistic。*39。d39。 39。t39。 新鄉(xiāng)學(xué)院本科畢業(yè)論文（設(shè)計） 23 plot(t， x， 39。*39。借此機(jī)會，我想對我的指導(dǎo)趙老師以及幫助過我的同學(xué)朋友致以最真摯的謝意。s Day on February 14, characterized by bouquets of roses, chocolates and romantic candlelight dinners, than they do about their homegrown day for lovers. Even Qixi is nowadays referred to as the Chinese Valentine39。s largest virgin forest, and known for its spring and ecological environment, Arxan is marveled at by many tourists as the purest land on earth. You cannot miss out the Autumn of Arxan. It is definitely the best with brightlycolored scenery full of emotions. Autumn in the northern part of the country es earlier than the South. A September rain followed by the footprints of Autumn brings more colors to the once emerald green mountain and blooming grassland. Shutterbugs flock to see for themselves the marvel of splendid colors around the mountains and waters, many of whom have travel a long distance and even camp here only to capture a moment of the nature wonder. The silver birch turns golden, while the larch is still proudly green. You will find yourself drowned in the intoxicating red of the wild fruits as well as the glamour of flowers in full blown. And your heart will be lingering on the woods as it39。她在本文的選題、構(gòu)思和撰寫等方面給以了我很好的指導(dǎo)、極大的幫助，也在我論文的修改上給予了許多好的建議，多次認(rèn)真的審閱和耐心的指導(dǎo)使我的論文得到了不斷的完善，乃至終于定稿。 y=[ ]。 plot(t， x， 39。b(1)./(1+(b(1)/).*exp(b(2).*t))39。 ，39。c/(1+(c/)*exp( 8*d))=39。 則 (9)式可寫為 ）（ 10 當(dāng) , (0)LZ 均已知時，當(dāng) nt ?3,2,1? 時，通過多次迭代，則不難得到 ( ) (0)nZ t L Z? ． ）（ 11 其中若 （ 10） 式中的元素滿足： b 0 , = 1 , 2 , , , b 0iiin? 且 至 少 一 個 ． ( 1) ( )Z t LZ t?? ，s 0, =1,2, , 1。 Matlab software。) [c ， d]=solve(39。)。d39。)。*39。) 新鄉(xiāng)學(xué)院本科畢業(yè)論文（設(shè)計） 24 致 謝 在論文基本定稿的時候，我心里夾雜著難以表達(dá)的傷感和欣喜，畢業(yè)論文是我即將畢業(yè)的主要任務(wù)之一，這一個任務(wù)飽含了指導(dǎo)老師的誨人不倦、朋友同學(xué)的幫助以及自己一點一滴的努力。 總之，感謝所有幫助過我、給予我善意微笑的老師和同學(xué)們，在這四年里給了我莫大的幫助和關(guān)懷，讓我的青春歲月充滿友誼的光輝和溫暖。s Day. More and more young Chinese people begin to celebrate this day in a very similar way as that in western countries. Fewer people than ever will gaze at the heavens on Saturday to pick out the two stars shining bright on either side of the Milky Way, that is, if people even know on which day Qixi falls. There are ready 新鄉(xiāng)學(xué)院本科畢業(yè)論文（設(shè)計） 26 reminders dotted about, in the form of big ads saying Sales on Chinese Valentine39。 ll wait in the line for one hour to get a ticket, and another two hours at the site, to only see a tiny bit of the place due to the crowds. Last year, 428 million tourists traveled in China over the weeklong holiday in October. Traveling during this period is a matter that needs thorough preparation. If you are short on time to plan the uping Golden Week it may not be a bad idea to avoid some of the most crowded places for now. There is always a place so fascinating that everyone yearns for. Arxan is a place like this. The beauty of Arxan is everlasting regardless of the changing of four seasons. Bestowed by nature, its spectacular seasonal landscape and mountains are just beyond word. Arxan is a crucial destination for the remended travelling route, China Inner Mongolia Arxan — Hailar — Manzhouli. It is also the joint of the four prairies across the SinoMongolian border, where people gravitate towards the exotic atmosphere mixed with Chinese, Russian, and Mongolia elements. As a historic site for the Yitian Battle, Arxan still embodies the spirit of Genghis Khan. Walking into Arxan, you will be amazed by a kaleidoscope of geous colors all the year round the Spring azaleas blooming red in the snow, the Summer sea wavering blue in the breeze, the Autumn leaves painted in yellow covering volcanic traces, and the Winter woods shining white on the vast alpine snowscape. Hinggan League Arxan city is situated in the far eastern area of Inner Mongolia Autonomous Region. Its full name Haren Arxan means hot holy water in the Mongolian language. Arxan is a tourism city in the northern frontier with a blend of large forest, grand prairies, vast snowfield, heaven lake cluster, thermium, as well as volcanic cluster. It is a rare and unique ecotourism base filled with healthy sunshine, clean air and unspoiled green. Nestled close to the country39。 最想感謝的是我的指導(dǎo)教師 —— 趙守娟老師，一位見聞廣博而又耐心細(xì)致的良師。 x=[ ]。 b R=sum(r.^2) x1=./(1+().*exp(.*t))。 fun=inline(39。c/(1+(c/)*exp(5*d))=39。 ，39。、。 Leslie matrix 新鄉(xiāng)學(xué)院本科畢業(yè)論文（設(shè)計） 3 第 1 章 問題的提出與分析 問題的提出 人口問題是關(guān)乎國家生存與發(fā)展的重大戰(zhàn)略問題．人口的增長取決于各種環(huán)境因素，合理的人口預(yù)測是一個非常重要的課題． 上世紀(jì) 90年代初 ， 我國人口總量雖然保持持續(xù)增長 ， 但慣性趨弱 ． 如果維持現(xiàn)行 計劃 生育政策不變 ， 總?cè)丝谠谶_(dá)到峰值后將快速減少 ． 隨著經(jīng)濟(jì)社會的發(fā)展和群眾生活水平的提高 ， 少生優(yōu)生、優(yōu)育優(yōu)教 的生育觀念正在形成 [1]．我國于 2022年實行單獨二胎政策，對我國人口的數(shù)量、結(jié)構(gòu)將產(chǎn)生很大的影響．因此， 預(yù)測放開二胎對我國人口增長的影響是當(dāng)前我國宏觀人口政策研究的一個重要課題 [2]． 問題的分析 人口的增長取決于各種環(huán)境因素，我國從 20世紀(jì) 80年代開始實行計劃生育至今，政策的壓制對我國人口的增長模式具有深遠(yuǎn)的影響，同時在經(jīng)過 30多年的非自然增長的條件下，我國人口將會呈現(xiàn)出更為復(fù)雜的形式，包括老齡化進(jìn)