畢業(yè)設(shè)計(jì)基于AT89C51單片機(jī)的水位控制系統(tǒng)設(shè)計(jì)

1、單片機(jī)原理及系統(tǒng)課程設(shè)計(jì)報(bào)告1 引言1.1 設(shè)計(jì)目的在工農(nóng)業(yè)生產(chǎn)中，常常需要測(cè)量液體液位。隨著國(guó)家工業(yè)的迅速發(fā)展，液位測(cè)量技術(shù)被廣泛應(yīng)用到石油、化工、醫(yī)藥、食品等各行各業(yè)中。低溫液體（液氧、液氮、液氬、液化天然氣及液體二氧化碳等）得到廣泛的應(yīng)用，作為貯存低溫液體的容器要保證能承受其載荷；在發(fā)電廠、煉鋼廠中，保持正常的鍋爐汽包水位、除氧器水位、汽輪機(jī)凝氣器水位、高、低壓加熱器水位等，是設(shè)備安全運(yùn)行的保證，因此一個(gè)安全合適的水位系統(tǒng)是很必要的。1.2 設(shè)計(jì)要求利用單片機(jī)設(shè)計(jì)一個(gè)水位控制系統(tǒng)，要求用開關(guān)來(lái)模擬水位的狀態(tài)，當(dāng)設(shè)定完水位后，系統(tǒng)根據(jù)水位情況控制電磁閥的開啟和關(guān)斷。具體要求如下：1、設(shè)計(jì)單

2、片機(jī)工作系統(tǒng)電路。2、通過(guò)鍵盤設(shè)置其預(yù)定水位，根據(jù)水位不同控制電機(jī)的旋轉(zhuǎn)。5、利用proteus進(jìn)行仿真。1.3 設(shè)計(jì)方法本設(shè)計(jì)是采用at89c51單片機(jī)為核心芯片,及其相關(guān)硬件來(lái)實(shí)現(xiàn)的水體液位控制系統(tǒng),采用八個(gè)鍵盤來(lái)模擬水位, cpu循環(huán)檢鍵盤輸入狀態(tài),并用3位七段led顯示示液位高度,檢測(cè)液位數(shù)據(jù),實(shí)施報(bào)警安全提示,當(dāng)水體液位低于用戶設(shè)定的值時(shí),系統(tǒng)自動(dòng)打開泵上水,當(dāng)水位到達(dá)設(shè)定值時(shí),系統(tǒng)自動(dòng)打開排水泵。2 設(shè)計(jì)方法和原理2.1 水塔水位的控制原理單片機(jī)水塔水位控制原理如圖l所示，圖中的虛線表示允許水位變化的上、下限位置。在正常情況下水位應(yīng)控制在虛線范圍之內(nèi)。為此，在水塔內(nèi)的不同高度處，安

3、裝固定不變的3根金屬棒a、b、c。用以反映水位變化的情況。其中，a棒在下限水位b棒在上、下限水位之間，c棒在上限水位(底端靠近水池底部不能過(guò)低，要保證有足夠大的流水量)。水塔由電機(jī)帶動(dòng)水泵供水。單片機(jī)控制電機(jī)轉(zhuǎn)動(dòng)，隨著供水，水位不斷上升當(dāng)水位上升到上限水位時(shí)，由于水的導(dǎo)電作用。使b、c棒均與+5 v連通。因此b、c兩端的電壓都為+5 v，即為“l(fā)”狀態(tài)，此時(shí)應(yīng)停止電機(jī)和水泵工作，不再向水塔注水；隨著水量的減少，當(dāng)水位處于上、下限之間時(shí)。b棒和a棒導(dǎo)通而c棒不能與a棒導(dǎo)通，b端為“1”狀態(tài)。c端為“0”狀態(tài)。此時(shí)電機(jī)帶動(dòng)水泵給水塔注水，使水位上升，或是電機(jī)不工作，水位不斷下降，都應(yīng)繼續(xù)維持原有工

4、作狀態(tài)；當(dāng)水位處于下限位置以下時(shí)，b、c棒均不能與a棒導(dǎo)通，b、c均為“0”狀態(tài)。此時(shí)應(yīng)啟動(dòng)電機(jī)轉(zhuǎn)動(dòng)，帶動(dòng)水泵給水塔注水，然后重復(fù)原來(lái)的過(guò)程，這就是簡(jiǎn)單的水位控制原理。圖1 水位控制原理2.2 總體設(shè)計(jì)方案系統(tǒng)的原理是采用8個(gè)按鈕進(jìn)行水位檢測(cè)，在現(xiàn)場(chǎng)的3個(gè)不同的位置，由下至上測(cè)量水體的液位值。并把這八個(gè)液位狀態(tài)通過(guò)模數(shù)轉(zhuǎn)換器傳到單片機(jī)中（在本系統(tǒng)中采用開關(guān)的打開與閉合來(lái)模擬）,在通過(guò)3位七段led顯示器顯示出液位的八種狀態(tài)并通過(guò)led燈報(bào)警提示。當(dāng)水位過(guò)低（在3水位）時(shí)燈就會(huì)變亮，當(dāng)水位較高（在7水位時(shí)）等也會(huì)變亮，用來(lái)讓用戶察覺(jué)。在水位過(guò)高和過(guò)低時(shí)電磁閥都會(huì)自動(dòng)的抽水或排水，其具體的抽水和排

5、水位置可以設(shè)定，此系統(tǒng)中采用的是7水位和3水位。3 硬件設(shè)計(jì)3.1 硬件設(shè)計(jì)方案系統(tǒng)方案設(shè)計(jì)液位控制是利用把液位的利用來(lái)管進(jìn)行模擬，再通過(guò)at89c51把輸出狀態(tài)直接接到單片機(jī)的i/o接口，單片機(jī)經(jīng)過(guò)運(yùn)算控制，輸出數(shù)字信號(hào)，輸出接口接led進(jìn)行顯示,實(shí)現(xiàn)液位的報(bào)警和鍵盤的顯示與控制。由下圖可觀察到水位由鍵盤控制輸入以后，通過(guò)at89c51單片機(jī)的運(yùn)算控制，在通過(guò)led進(jìn)行顯示,通過(guò)報(bào)警裝置進(jìn)行報(bào)警,報(bào)警顯示之后再通過(guò)對(duì)閥門的開啟實(shí)現(xiàn)對(duì)水體的液位進(jìn)行調(diào)節(jié)控制,閥門的驅(qū)動(dòng)設(shè)備是電動(dòng)機(jī)。圖2即是液位控制系統(tǒng)。圖2 水位控制系統(tǒng)分析3.2 主芯片at89c51本系統(tǒng)采用at89c51作為主要芯片，at

6、89c51是一種帶4k字節(jié)flash存儲(chǔ)器的低電壓、高性能cmos 8位微處理器，俗稱單片機(jī)。單片機(jī)的可擦除只讀存儲(chǔ)器可以反復(fù)擦除1000次。該器件采用atmel高密度非易失存儲(chǔ)器制造技術(shù)制造，與工業(yè)標(biāo)準(zhǔn)的mcs-51指令集和輸出管腳相兼容。由于將多功能8位cpu和閃爍存儲(chǔ)器組合在單個(gè)芯片中，atmel的at89c51是一種高效微控制器。at89c51單片機(jī)為很多嵌入式系統(tǒng)提供了一種靈活性高且價(jià)廉的方案。在本系統(tǒng)設(shè)計(jì)中采用at89c51作為主要的芯片，它具有p0、p1、p2、p3四個(gè)i/o口，每個(gè)口又有8個(gè)接口，32個(gè)接口可以滿足外接電路的需要，更方便的顯示系統(tǒng)。本設(shè)計(jì)中采用了單片機(jī)at89c

7、51的p0、p1、p3口，分別完成了顯示和控制以及報(bào)警功能的實(shí)現(xiàn)。下圖為單片機(jī)at89c51的引腳圖。圖3 at89c51引腳圖3.3 光報(bào)警及顯示電路 圖4所示為系統(tǒng)的光報(bào)警及顯示電路，三段led數(shù)碼管于單片機(jī)的p0-p7口相連，同時(shí)排阻的把根線也連在單片機(jī)的p0口上，作為上拉電阻。圖4 光報(bào)警及顯示電路3.4 鍵盤連接電路鍵盤連接電路如圖5所示，八個(gè)鍵盤k1-k8分別與單片機(jī)的p1口的p1-p7相連，這八個(gè)鍵盤的按下與否用來(lái)模擬的是水位的高低，k1鍵代表水位最低點(diǎn)，k8鍵代表的是水位最高點(diǎn)，當(dāng)k1鍵按下時(shí)，指示燈亮，電機(jī)正轉(zhuǎn)，開始加水，一直加水至水位7（即7鍵按下時(shí)），電機(jī)開始停止轉(zhuǎn)動(dòng)，并

8、反向轉(zhuǎn)動(dòng)抽水，水位開始降低，直至到達(dá)3水位，燈亮電機(jī)開始自動(dòng)加水，加水水位可以由用戶自己設(shè)定，本系統(tǒng)中采取的是3水位便開始加水，7水位開始抽水。本系統(tǒng)采用的是獨(dú)立式鍵盤結(jié)構(gòu)，每個(gè)按鍵單獨(dú)占用一根i/o口線，每個(gè)按鍵的工作不會(huì)影響其它i/o口線的狀態(tài)。它軟件是采用查詢式結(jié)構(gòu)，首先逐位查詢每根i/o口線的輸入狀態(tài)，如某一根i/o口線輸入為低電平，則可確認(rèn)該i/o口線所對(duì)應(yīng)的按鍵已按下，然后，再轉(zhuǎn)向該鍵的功能處理程序。圖5 鍵盤連接電路3.5 復(fù)位電路系統(tǒng)的復(fù)位電路如圖6所示。復(fù)位電路中上端于單片機(jī)的復(fù)位引腳相連，下面與與ea端相連，要使cpu只訪問(wèn)外部程序存儲(chǔ)器（地址為0000hffffh），則e

9、a端必須保持低電平（接到gnd端）。然而要注意的是，如果保密位lb1被編程，復(fù)位時(shí)在內(nèi)部會(huì)鎖存ea端的狀態(tài)。當(dāng)ea端保持高電平（接vcc端）時(shí)，cpu則執(zhí)行內(nèi)部程序存儲(chǔ)器中的程序。其復(fù)位電路部分用來(lái)對(duì)系統(tǒng)進(jìn)行復(fù)位操作，末端與單片機(jī)的復(fù)位相連，按下復(fù)位鍵，當(dāng)振蕩器運(yùn)行時(shí)，在該引腳上出現(xiàn)兩個(gè)機(jī)器周期的高電平將使單片機(jī)復(fù)位。圖6 復(fù)位電路3.6 晶振電路晶體振蕩電路的兩個(gè)端口分別連接在單片機(jī)的xtal1和xtal2上。晶振電路的作用是為本系統(tǒng)提供基本的時(shí)鐘信號(hào)。通常一個(gè)系統(tǒng)共用一個(gè)晶振，便于各部分保持同步。有些通訊系統(tǒng)的基頻和射頻使用不同的晶振，而通過(guò)電子調(diào)整頻率的方法保持同步。晶振電路通常與鎖相環(huán)

10、電路配合使用，以提供系統(tǒng)所需的時(shí)鐘頻率。如果不同子系統(tǒng)需要不同頻率的時(shí)鐘信號(hào)，可以用與同一個(gè)晶振相連的不同鎖相環(huán)來(lái)提供。圖7 晶振電路4 軟件設(shè)計(jì)4.1 程序流程圖及其分析水位檢測(cè)是通過(guò)7個(gè)按鈕進(jìn)行水位檢測(cè)的，當(dāng)水位到檢測(cè)位置其輸出端口就向單片機(jī)輸出低電平。由上至下的第一個(gè)位置為水位上限報(bào)警線，即當(dāng)水位高于此位置時(shí)，開水閥控制系統(tǒng)就會(huì)自動(dòng)報(bào)警，提醒工作人員注意，加水電磁閥有可能出故障；第二個(gè)位置是自動(dòng)停止加水線，即當(dāng)水位高于此位置時(shí)，控制系統(tǒng)會(huì)自動(dòng)關(guān)閉加水電磁閥，停止加水；第三個(gè)位置是自動(dòng)加水線，即當(dāng)水位低于此位置時(shí)，控制系統(tǒng)會(huì)自動(dòng)接通加水電磁閥，開始加水；第四個(gè)位置是水位下限報(bào)警線，即當(dāng)水位

11、低于此位置時(shí)，控制系統(tǒng)就會(huì)自動(dòng)報(bào)警，提醒工作人員。本設(shè)計(jì)的一個(gè)較大的優(yōu)點(diǎn)是可以設(shè)置多個(gè)水位，既用戶可根據(jù)自己需要設(shè)定加水時(shí)的水位。根據(jù)所分析的該系統(tǒng)的具體功能，可以畫出該系統(tǒng)的流程圖，流程圖應(yīng)該盡量力求簡(jiǎn)便，而且從中可以較容易的看出設(shè)計(jì)者的目的，充分的了解所需設(shè)計(jì)的系統(tǒng)的功能，從而根據(jù)流程圖編寫程序。圖8 水位控制流程圖5 系統(tǒng)仿真及實(shí)際調(diào)試5.1 元器件清單7seg-com-cat-grnled數(shù)碼管at89c1單片機(jī)button按鈕cap電容g2rl-1a-cf-dc5繼電器2n6609三極管cap-elec陶瓷電容crystal31兆晶振led-red發(fā)光二極管motor電機(jī)res電阻r

12、espack-8排阻5.2 系統(tǒng)調(diào)試及仿真將所有的硬件按照上面所說(shuō)的方法連接起來(lái)，將源程序在keil c中生成.hex文件，放在在proteus中連接好的電路圖中，運(yùn)行，則可得到正確的結(jié)果。圖9 水位控制系統(tǒng)仿真圖6 總結(jié) 設(shè)計(jì)過(guò)程中我遇到了很多的困難，因?yàn)橹R(shí)是不連貫的，所以需要準(zhǔn)備很多方面的知識(shí)去融合，去聯(lián)系。由于在學(xué)習(xí)的時(shí)候更注重的是書面上的東西，而本次課程設(shè)計(jì)更多的是鍛煉了我的動(dòng)手動(dòng)腦能力，讓我有機(jī)會(huì)把課上學(xué)習(xí)的知識(shí)轉(zhuǎn)化為可以在實(shí)際生產(chǎn)生活中應(yīng)用的技術(shù)。本次課程設(shè)計(jì)的系統(tǒng)主要介紹了水體的液位檢測(cè)控制，介紹了at89c51單片機(jī)和其它一些單片機(jī)在液位控制系統(tǒng)中的應(yīng)用，介紹了它們的引腳和在

13、系統(tǒng)中的電路圖，利用led來(lái)進(jìn)行信號(hào)的輸出顯示,我設(shè)計(jì)的硬件系統(tǒng)的結(jié)構(gòu)簡(jiǎn)化,系統(tǒng)精度高，具有良好的人機(jī)交互功能,并設(shè)有液位報(bào)警，有問(wèn)題立即就能發(fā)現(xiàn)。通過(guò)自動(dòng)調(diào)節(jié)控制液位并實(shí)現(xiàn)水體的液位報(bào)警。液位控制在設(shè)定值上正常運(yùn)行不需要人工干預(yù)，操作人員勞動(dòng)強(qiáng)度小。通過(guò)本次課程設(shè)計(jì)，我了解到自己的知識(shí)應(yīng)該充分利用在實(shí)踐上，在實(shí)踐中把書本上的知識(shí)固化成自己的能力。在設(shè)計(jì)系統(tǒng)的時(shí)候也有很多的想法，但是有一些想法被否定了，最終完成設(shè)計(jì)的時(shí)候優(yōu)先考慮了在課程上學(xué)習(xí)到的知識(shí)，并且和單片機(jī)、電子電路的知識(shí)結(jié)合起來(lái)。這次設(shè)計(jì)之后，我感覺(jué)到自己在自動(dòng)化專業(yè)上的學(xué)習(xí)應(yīng)該還有很長(zhǎng)的路走，自動(dòng)化是一個(gè)很有前途的行業(yè)，它涉及了生產(chǎn)

14、生活的多個(gè)方面，對(duì)人們的影響可想而知，所以，學(xué)好自動(dòng)化專業(yè)的知識(shí)不僅僅是對(duì)自己能力提升和自我價(jià)值的實(shí)現(xiàn)，更是一件很有意義，可以讓自己有所感觸，有所收獲的事業(yè)。參考文獻(xiàn)1 王思明. 單片機(jī)原理及應(yīng)用系統(tǒng)設(shè)計(jì).科學(xué)出版社.2012.2 陳明熒. 8051單片機(jī)課程設(shè)計(jì)實(shí)訓(xùn)教材. 清華大學(xué)出版社. 2004.3 丁明亮. 單片機(jī)原理及應(yīng)基于keil c 與proteus. 北京航空航天大學(xué)出版社. 2009-2.4 梅麗鳳. 單片機(jī)原理及接口技術(shù). 清華大學(xué)出版社.2006-8. 附錄源程序清單#include #define uchar unsigned char /*以后定義的uchar都認(rèn)為是

15、unsigned char*/#define uint unsigned int /*以后定義的uint都認(rèn)為是unsigned int*/sbit mor=p27; /*電機(jī)正極為p2.7口*/sbit mot=p26; /*電機(jī)負(fù)極為p2.6口*/sbit led=p20; /*led燈為p2.0口*/code uchar tab=0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f; /*定義一個(gè)碼存表*/void delay (uint n)while(n-); /*10ms的延時(shí)*/void led_show() if(p1=0xfe)

16、/*如果k8鍵按下*/ p0=tab8;/*p0=0x7f*/ led=0;/*led為低電平*/ mor=0;/*電機(jī)正極為低電平*/ mot=1;/*電機(jī)負(fù)極為高電平*/ if(p1=0xfd)/*如果k7鍵按下*/ p0=tab7;/*p0=0x07*/ led=0;/*p2.0為低電平*/ mor=0;/*電機(jī)正極為低電平*/ mot=1;/*電機(jī)負(fù)極為高電平*/ if(p1=0xfb) /*如果k6鍵按下*/ p0=tab6; /*p0=0x7d*/ led=1; /*p2.0為高電平*/ mor=1; /*電機(jī)正極為高電平*/ mot=1; /*電機(jī)負(fù)極為高電平*/ if(p1=0

17、xf7) /*如果k5鍵按下*/ p0=tab5; /*p0=0x6d*/ led=1; /*p2.0為高電平*/ mor=1; /*電機(jī)正極為高電平*/ mot=1; /*電機(jī)負(fù)極為高電平*/ if(p1=0xef) /*如果k4鍵按下*/ p0=tab4; /*p0=0x66*/ led=1; /*p2.0為高電平*/ mor=1; /*電機(jī)正極為高*/ mot=1; /*電機(jī)負(fù)極為高*/ if(p1=0xdf)/*如果k3鍵按下*/ p0=tab3;/*p0=0x4f*/ led=0;/*p2.0為低*/ mor=1;/*電機(jī)正極為高*/ mot=0;/*電機(jī)負(fù)極為低*/ if(p1=0

18、xbf) /*如果k2鍵按下*/ p0=tab2; /*p0=0x5b*/ led=0; /*p2.0為低電平*/ mor=1; /*電機(jī)正極為高電平*/ mot=0; /*電機(jī)負(fù)極為低電平*/ if(p1=0x7f) /*如果k1鍵按下*/ p0=tab1; /*p0=0x06*/ led=0; /*p2.0為低電平*/ mor=1; /*電機(jī)正極為高電平*/ mot=0; /*電機(jī)負(fù)極為低電平*/ void main()while(1) led_show();仿真運(yùn)行圖g an employment tribunal claiemployment tribunals sort out di

19、sagreements between employers and employees.you may need to make a claim to an employment tribunal if: you dont agree with the disciplinary action your employer has taken against you your employer dismisses you and you think that you have been dismissed unfairly.for more information about dismissal

20、and unfair dismissal, seedismissal.you can make a claim to an employment tribunal, even if you haventappealedagainst the disciplinary action your employer has taken against you. however, if you win your case, the tribunal may reduce any compensation awarded to you as a result of your failure to appe

21、al.remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are complaining about happened. if your application is received after this time limit, the tribunal will not usually accept i.if you are worried about how the time

22、 limits apply to you, take advice from one of the organisations listed underfurther help.employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation.most people find making a claim to an employment tribu

23、nal challenging. if you are thinking about making a claim to an employment tribunal, you should get help straight away from one of the organisations listed underfurther help.if you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out

24、 of your compensation if you win the case. this is known as adamages-based agreement. in england and wales, your solicitor cant charge you more than 35% of your compensation if you win the case.if you are thinking about signing up for a damages-based agreement, you should make sure youre clear about

25、 the terms of the agreement. it might be best to get advice from an experienced adviser, for example, at a citizens advice bureau. to find your nearest cab, including those that give advice by e-mail, click onnearest cab.for more information about making a claim to an employment tribunal, seeemploym

26、ent tribunals.the (lack of) air up there watch mcayman islands-based webb, the head of fifas anti-racism taskforce, is in london for the football associations 150th anniversary celebrations and will attend citys premier league match at chelsea on sunday.i am going to be at the match tomorrow and i h

27、ave asked to meet yaya toure, he told bbc sport.for me its about how he felt and i would like to speak to him first to find out what his experience was.uefa hasopened disciplinary proceedings against cskafor the racist behaviour of their fans duringcitys 2-1 win.michel platini, president of european

28、 footballs governing body, has also ordered an immediate investigation into the referees actions.cska said they were surprised and disappointed by toures complaint. in a statement the russian side added: we found no racist insults from fans of cska.age has reached the end of the beginning of a word.

29、 may be guilty in his seems to passing a lot of different life became the appearance of the same day; may be back in the past, to oneself the paranoid weird belief disillusionment, these days, my mind has been very messy, in my mind constantly. always feel oneself should go to do something, or write

30、 something. twenty years of life trajectory deeply shallow, suddenly feel something, do it.一字開頭的年齡已經(jīng)到了尾聲?；蛟S是愧疚于自己似乎把轉(zhuǎn)瞬即逝的很多個(gè)不同的日子過(guò)成了同一天的樣子；或許是追溯過(guò)去，對(duì)自己那些近乎偏執(zhí)的怪異信念的醒悟，這些天以來(lái)，思緒一直很凌亂，在腦海中不斷糾纏?？傆X(jué)得自己自己似乎應(yīng)該去做點(diǎn)什么，或者寫點(diǎn)什么。二十年的人生軌跡深深淺淺，突然就感覺(jué)到有些事情，非做不可了。the end of our life, and can meet many things really do?而窮

31、盡我們的一生，又能遇到多少事情是真正地非做不可？during my childhood, think lucky money and new clothes are necessary for new year, but as the advance of the age, will be more and more found that those things are optional; junior high school, thought to have a crush on just means that the real growth, but over the past thre

32、e years later, his writing of alumni in peace, suddenly found that isnt really grow up, it seems is not so important; then in high school, think dont want to give vent to out your inner voice can be in the high school children of the feelings in a period, but was eventually infarction when graduatio

33、n party in the throat, later again stood on the pitch he has sweat profusely, looked at his thrown a basketball hoops, suddenly found himself has already cant remember his appearance.童年時(shí)，覺(jué)得壓歲錢和新衣服是過(guò)年必備，但是隨著年齡的推進(jìn)，會(huì)越來(lái)越發(fā)現(xiàn)，那些東西根本就可有可無(wú)；初中時(shí)，以為要有一場(chǎng)暗戀才意味著真正的成長(zhǎng)，但三年過(guò)去后，自己心平氣和的寫同學(xué)錄的時(shí)候，突然就發(fā)現(xiàn)是不是真正的成長(zhǎng)了，好像并沒(méi)有那么重要了

34、；然后到了高中，覺(jué)得非要吐露出自己的心聲才能為高中生涯里的懵懂情愫劃上一個(gè)句點(diǎn)，但畢業(yè)晚會(huì)的時(shí)候最終還是被梗塞在了咽喉，后來(lái)再次站在他曾經(jīng)揮汗如雨的球場(chǎng)，看著他投過(guò)籃球的球框時(shí)，突然間發(fā)現(xiàn)自己已經(jīng)想不起他的容顏。originally, this world, can produce a chemical reaction to an event, in addition to resolutely, have to do, and time.原來(lái)，這個(gè)世界上，對(duì)某個(gè)事件能產(chǎn)生化學(xué)反應(yīng)的，除了非做不可的堅(jiān)決，還有，時(shí)間。a persons time, your ideas are always

35、special to clear. want, want, line is clear, as if nothing could shake his. also once seemed to be determined to do something, but more often is he backed out at last. dislike his cowardice, finally found that there are a lot of love, there are a lot of miss, like shadow really have been doomed. tho

36、se who do, just green years oneself give oneself an arm injection, or is a self-righteous spiritual.一個(gè)人的時(shí)候，自己的想法總是特別地清晰。想要的，不想要的，界限明確，好像沒(méi)有什么可以撼動(dòng)自己。也曾經(jīng)好像已經(jīng)下定了決心去做某件事，但更多的時(shí)候是最后又打起了退堂鼓。嫌惡過(guò)自己的怯懦，最終卻發(fā)現(xiàn)有很多緣分，有很多錯(cuò)過(guò)，好像冥冥之中真的已經(jīng)注定。那些曾經(jīng)所謂的非做不可，只是青蔥年華里自己給自己注射的一支強(qiáng)心劑，或者說(shuō)，是自以為是的精神寄托罷了。at the moment, the sky is dar

37、k, the air is fresh factor after just rained. suddenly thought of blue plaid shirt; those were broken into various shapes of stationery; from the corner at the beginning of deep friendship; have declared the end of the encounter that havent start planning. those years, those days of do, finally, lik

38、e youth, will end in our life.此刻，天空是陰暗的，空氣里有著剛下過(guò)雨之后的清新因子。突然想到那件藍(lán)格子襯衫；那些被折成各種各樣形狀的信紙；那段從街角深巷伊始的友誼；還有那場(chǎng)還沒(méi)有開始就宣告了終結(jié)的邂逅計(jì)劃那些年那些天的非做不可，終于和青春一樣，都將在我們的人生中謝幕。baumgartner the disappointing news: mission aborted. r plays an important role in this mission. starting at the ground, conditions have to be very calm

39、 - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. the balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. it will climb higher than the tip of mount everest (5.5 miles/8.85 kilome

40、ters), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. as he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.the supersonic descent could happen as early as sunda.the weathethe balloon will slowly drift to the edge of space at 120,000 feet ( then, i would a