本科畢業(yè)論文基于PLC的煤礦礦車(chē)防跑車(chē)系統(tǒng)設(shè)計(jì)定稿

1、基于plc的煤礦礦車(chē)防跑車(chē)系統(tǒng)設(shè)計(jì)摘要:隨著自動(dòng)控制理論和 PLC 技術(shù)的發(fā)展，具有易于使用、功能強(qiáng)大、高可靠性、擴(kuò)展能力強(qiáng)、廣泛的適用性和組成控制系統(tǒng)的簡(jiǎn)潔性等諸多優(yōu)點(diǎn)的PLC控制技術(shù)，得到了越來(lái)越廣泛的應(yīng)用。本論文以作者研究的基于PLC的煤礦礦車(chē)防跑車(chē)系統(tǒng)項(xiàng)目為背景，從PLC控制系統(tǒng)設(shè)計(jì)的角度，探討PLC控制技術(shù)的應(yīng)用。本課題主要是對(duì)基于PLC的煤礦礦車(chē)防跑車(chē)系統(tǒng)進(jìn)行設(shè)計(jì)，以實(shí)現(xiàn)有效的對(duì)擋車(chē)欄進(jìn)行手動(dòng)控制和自動(dòng)控制；并且能夠?qū)ΦV車(chē)的運(yùn)行狀態(tài)進(jìn)行實(shí)時(shí)監(jiān)控，當(dāng)?shù)V車(chē)運(yùn)行出現(xiàn)問(wèn)題時(shí)可及時(shí)報(bào)警并控制擋車(chē)欄對(duì)礦車(chē)進(jìn)行攔截；能夠?qū)崿F(xiàn)與上位機(jī)進(jìn)行通訊，可以在人機(jī)界面中觀察礦車(chē)狀態(tài)并進(jìn)行手動(dòng)操作。本次設(shè)計(jì)應(yīng)

2、用小型可編程控制器（西門(mén)子S7-200 CPU224）作為控制系統(tǒng)硬件部分控制核心，采用組態(tài)王設(shè)計(jì)人機(jī)界面，使用CAD制圖軟件繪制電氣原理圖，采用西門(mén)子STEP7-MicroWIN編程軟件進(jìn)行編程。程序調(diào)試結(jié)果表明本次設(shè)計(jì)的系統(tǒng)能夠?qū)崿F(xiàn)對(duì)礦用擋車(chē)欄的自動(dòng)和手動(dòng)控制，可與上位機(jī)進(jìn)行通訊。 本設(shè)計(jì)可應(yīng)用于現(xiàn)場(chǎng)工作。關(guān)鍵詞：PLC 擋車(chē)欄 控制系統(tǒng) 通訊前 言斜井軌道提升時(shí)煤礦提升系統(tǒng)中的一個(gè)重要組成部分，但目前斜井軌道提升系統(tǒng)在運(yùn)行過(guò)程中跑車(chē)事故發(fā)生頻率較高，是煤礦安全生產(chǎn)的薄弱環(huán)節(jié)。特別是一些煤礦由于資金匱乏、人為操作較多等原因，造成裝置磨損老化，容易出現(xiàn)鋼絲繩斷裂，發(fā)生跑車(chē)事故。煤礦跑車(chē)事故危

3、害嚴(yán)重，除了撞壞設(shè)施外，還會(huì)造成人員傷亡等嚴(yán)重后果。為了解決這一問(wèn)題，多數(shù)煤礦選擇在斜井中安裝擋車(chē)欄裝置，擋車(chē)欄裝置可以有效的對(duì)發(fā)生跑車(chē)的礦車(chē)進(jìn)行攔截，避免造成重大人員傷亡及財(cái)產(chǎn)損失。本文設(shè)計(jì)的就是一款基于PLC的煤礦礦車(chē)防跑車(chē)系統(tǒng)?？删幊炭刂破鳎ê?jiǎn)稱(chēng)PLC）是一種新型的具有極高可靠性的通用工業(yè)自動(dòng)化控制裝置。它具有控制能力強(qiáng)、可靠性高、配置靈活、編程簡(jiǎn)單、方便使用、易于擴(kuò)展等優(yōu)點(diǎn)，是當(dāng)今工業(yè)控制的主要手段和重要的自動(dòng)化控制設(shè)備。本設(shè)計(jì)選用西門(mén)子S7-200中CPU224系列PLC作為控制核心。要求設(shè)計(jì)一個(gè)由PLC自動(dòng)控制的擋車(chē)欄系統(tǒng)，由位置傳感器檢測(cè)車(chē)輛有無(wú)并計(jì)算車(chē)速，若礦車(chē)超速則自動(dòng)開(kāi)啟擋

4、車(chē)欄攔截礦車(chē)，可有效的減少由礦車(chē)跑車(chē)造成的損失。第一章煤礦礦車(chē)防跑車(chē)系統(tǒng)研究背景和設(shè)計(jì)與實(shí)現(xiàn)1煤礦礦車(chē)防跑車(chē)系統(tǒng)研究背景目前我國(guó)礦山井下輔助運(yùn)輸絕大多數(shù)仍然以軌道運(yùn)輸為主要方式，斜巷軌道運(yùn)輸又是煤礦輔助運(yùn)輸?shù)闹匾画h(huán)，其特點(diǎn)是工作范圍廣、戰(zhàn)線長(zhǎng)、占用設(shè)備多、設(shè)備設(shè)施流動(dòng)性大、涉及人員多。在目前煤礦生產(chǎn)中，運(yùn)輸事故還占有很大的比例。在斜巷礦車(chē)移動(dòng)中，由于絞車(chē)司機(jī)的違章作業(yè)、信號(hào)把鉤工的不規(guī)范推車(chē)、連掛車(chē)和礦車(chē)連接裝置的不完好等原因,易發(fā)生跑車(chē)事故。一旦發(fā)生跑車(chē)，就可能造成設(shè)備損壞、中斷斜巷運(yùn)輸,造成嚴(yán)重的經(jīng)濟(jì)損失，嚴(yán)重的還會(huì)造成人員傷亡,對(duì)礦井的安全生產(chǎn)造成嚴(yán)重影響。2煤礦礦車(chē)防跑車(chē)裝系統(tǒng)功能介

5、紹本設(shè)計(jì)任務(wù)是針對(duì)基于PLC的礦用擋車(chē)欄系統(tǒng)進(jìn)行設(shè)計(jì)。該系統(tǒng)應(yīng)實(shí)現(xiàn)以下功能要求：(1) 能夠有效的對(duì)擋車(chē)欄進(jìn)行控制，分為手動(dòng)控制和自動(dòng)控制兩種方式；(2) 能夠?qū)ΦV車(chē)的運(yùn)行狀態(tài)進(jìn)行實(shí)時(shí)監(jiān)控，當(dāng)?shù)V車(chē)運(yùn)行出現(xiàn)問(wèn)題時(shí)可及時(shí)報(bào)警并控制擋車(chē)欄對(duì)礦車(chē)進(jìn)行攔截。3煤礦礦車(chē)防跑車(chē)系統(tǒng)的設(shè)計(jì)與實(shí)現(xiàn)由于礦車(chē)在煤礦、金屬礦山、非金屬礦山等所有傾角在30°以下的單軌提升運(yùn)輸斜巷中運(yùn)行，當(dāng)斜巷礦車(chē)發(fā)生跑車(chē)時(shí)，將會(huì)造成很大安全事故，造成人身設(shè)備傷亡?；谏鲜霰尘埃菊绿接懨旱V礦車(chē)防跑車(chē)系統(tǒng)的設(shè)計(jì)與實(shí)現(xiàn)，該系統(tǒng)是對(duì)發(fā)生跑車(chē)的礦車(chē)進(jìn)行有效攔截以免擴(kuò)大事故，特別適合于復(fù)合型斜巷中。整個(gè)煤礦礦車(chē)防跑車(chē)系統(tǒng)主要包括控制系

6、統(tǒng)部分和機(jī)械部分。煤礦礦車(chē)防跑車(chē)系統(tǒng)主要由核心控制器、位置檢測(cè)系統(tǒng)、擋車(chē)欄系統(tǒng)、監(jiān)控報(bào)警系統(tǒng)等部分組。圖1-1 煤礦礦車(chē)防跑車(chē)系統(tǒng)結(jié)構(gòu)圖第二章煤礦礦車(chē)防跑車(chē)系統(tǒng)總體設(shè)計(jì)1速度檢測(cè)原理 要檢測(cè)礦車(chē)在斜井中的運(yùn)行速度， 經(jīng)過(guò)分析，提出了在斜井坡上，每隔一段距離安裝一個(gè)位置傳感器，用來(lái)檢測(cè)礦車(chē)在某段時(shí)間內(nèi)運(yùn)動(dòng)的距離，從而計(jì)算出礦車(chē)運(yùn)行的速度。圖3-3分多段檢測(cè)礦車(chē)運(yùn)行速度方案。 圖2-1 傳感器位置示意圖圖2-1中所示，斜井坡長(zhǎng)分2段進(jìn)行檢測(cè)礦車(chē)運(yùn)行的速度，一共裝有3個(gè)位置檢測(cè)傳感器，相互之間的距離分別為L(zhǎng)1和L2。礦車(chē)運(yùn)行至拐點(diǎn)處，第一個(gè)傳感器檢測(cè)，運(yùn)行時(shí)間T1，斜坡上的第二個(gè)傳感器檢測(cè)到礦車(chē)運(yùn)行

7、信號(hào)，此時(shí)計(jì)算出礦車(chē)速度V1,礦車(chē)?yán)^續(xù)運(yùn)行至第三個(gè)傳感器，運(yùn)行時(shí)間為T(mén)2，從而可以再次計(jì)算出，此時(shí)的礦車(chē)運(yùn)行的速度。2系統(tǒng)閉環(huán)控制原理 由擋車(chē)欄的工作原理可知，每次擋車(chē)欄的開(kāi)啟，與礦車(chē)在斜坡上的運(yùn)動(dòng)速度有關(guān)，當(dāng)速度大于某個(gè)設(shè)定值時(shí)，擋車(chē)欄自動(dòng)啟動(dòng)。 圖2-2 防跑車(chē)系統(tǒng)閉環(huán)控制原理圖圖2-2為系統(tǒng)閉環(huán)控制原理圖。由圖可知，PLC、絞車(chē)電機(jī)和速度檢查檢測(cè)三者構(gòu)成一個(gè)閉環(huán)控制回路。PLC接收到礦車(chē)位置檢測(cè)信號(hào)，計(jì)算出礦車(chē)的運(yùn)行的速度，若礦車(chē)超速則控制絞車(chē)電機(jī)開(kāi)啟擋車(chē)欄，鋼絲繩網(wǎng)將礦車(chē)的動(dòng)能轉(zhuǎn)換為彈性勢(shì)能，然后通過(guò)吸能器把彈性勢(shì)能吸收，礦車(chē)安全平穩(wěn)停下，避免事故發(fā)生。3煤礦礦車(chē)防跑車(chē)系統(tǒng)硬件設(shè)計(jì)合理

8、選擇PLC對(duì)于提高PLC控制系統(tǒng)的性價(jià)比起著重要作用，PLC的選擇應(yīng)包括機(jī)型的選擇、容量的選擇、I/O模塊的選擇、電源模塊的選擇等幾個(gè)方面。在煤礦礦車(chē)防跑車(chē)系統(tǒng)中，經(jīng)過(guò)調(diào)研、分析，選擇了德國(guó)西門(mén)子公司生產(chǎn)的S7-200系列PLC作為系統(tǒng)的控制器。西門(mén)子S7-200系列，是S7系列中最先進(jìn)的超級(jí)微型PLC，除了具有一般輸入輸出的功能外，還具有模擬量控制、定位控制等特殊功能。 S7-224系列PLC產(chǎn)品性能說(shuō)明如下： 控制點(diǎn)數(shù)(I/O)最大允許擴(kuò)展到 256 點(diǎn)。 布爾量的運(yùn)算速度(0.22µs)。 內(nèi)置6個(gè)高速計(jì)數(shù)器 。 輔助繼電器：M,S,L等；計(jì)時(shí)器：256 點(diǎn)；計(jì)數(shù)器：256點(diǎn)；

9、數(shù)據(jù)寄存器：VB,VW,VD等。 豐富的功能擴(kuò)展模塊(最大可擴(kuò)展7個(gè)模塊)。在防跑車(chē)欄控制系統(tǒng)中，采用組態(tài)軟件設(shè)計(jì)的人機(jī)操作界面，可節(jié)省許多PLC的輸入/輸出點(diǎn)數(shù)。經(jīng)過(guò)分析，確定煤礦礦車(chē)防跑車(chē)系統(tǒng)共需要5點(diǎn)輸入和4點(diǎn)輸出，為了以后的調(diào)整和工藝改進(jìn)的需要，在實(shí)際統(tǒng)計(jì)的I/O點(diǎn)數(shù)基礎(chǔ)上，一般應(yīng)加上1020的備用量，因此選用了S7-00中CPU224 型PLC，它具有14點(diǎn)輸入和10點(diǎn)輸出。4電氣原理圖圖2-3 防跑車(chē)控制系統(tǒng)電氣原理圖輸入端：I0.0I0.2分別為三個(gè)傳感器的檢測(cè)信號(hào)。在程序中用于控制定時(shí)器T37與T38，通過(guò)定時(shí)器即可得出礦車(chē)運(yùn)行時(shí)間，計(jì)算出礦車(chē)速度。I0.5I0.6為擋車(chē)欄開(kāi)啟

10、上限和下限返回信號(hào)。在程序中設(shè)定一個(gè)開(kāi)啟信號(hào)返回時(shí)間，如果沒(méi)有在規(guī)定時(shí)間內(nèi)收到返回信號(hào)，則說(shuō)明擋車(chē)欄由于某些原因并未完全開(kāi)啟或關(guān)閉，需要及時(shí)報(bào)警以免發(fā)生事故。輸出端：Q0.0為電機(jī)正轉(zhuǎn)輸出，控制擋車(chē)欄開(kāi)啟。Q0.1為電機(jī)反轉(zhuǎn)輸出，控制擋車(chē)欄關(guān)閉。Q0.2為礦車(chē)電機(jī)輸出，用于控制礦車(chē)的啟動(dòng)與停止。Q0.3為報(bào)警輸出。表2-1 煤礦礦車(chē)防跑車(chē)系統(tǒng)PLC輸入/輸出模塊對(duì)應(yīng)用途輸入信號(hào)輸出信號(hào)編號(hào)用途編號(hào)用途I0.0檢測(cè)礦車(chē)位置傳感器信號(hào)Q0.0檔車(chē)欄提升電機(jī)正傳KM1（開(kāi)啟）I0.1檢測(cè)礦車(chē)位置傳感器信號(hào)Q0.1檔車(chē)欄提升電機(jī)反傳KM2（關(guān)閉）I0.2檢測(cè)礦車(chē)位置傳感器信號(hào)Q0.2礦車(chē)電機(jī)回路驅(qū)動(dòng)K

11、M3I0.3備用Q0.3系統(tǒng)故障報(bào)警輸出KM4I0.4備用Q0.4備用I0.5檢測(cè)擋車(chē)欄提升信號(hào)開(kāi)到位Q0.5備用I0.6檢測(cè)擋車(chē)欄提升信號(hào)開(kāi)到位Q0.6備用5煤礦礦車(chē)防跑車(chē)系統(tǒng)PLC程序經(jīng)過(guò)詳細(xì)研究擋車(chē)欄的工作原理和控制要求，該系統(tǒng)PLC程序設(shè)計(jì)采用了分系統(tǒng)設(shè)計(jì)的思想，主要包括三個(gè)部分：位置檢測(cè)系統(tǒng)、擋車(chē)欄系統(tǒng)、監(jiān)控報(bào)警系統(tǒng)。程序的編寫(xiě)采用梯形圖編程方式。使用西門(mén)子公司的V4.0 STEP7-MicroWIN SP6編程軟件。 6位置檢測(cè)系統(tǒng)位置檢測(cè)系統(tǒng)是礦車(chē)運(yùn)行在斜坡導(dǎo)軌上重要的檢測(cè)系統(tǒng)，實(shí)時(shí)反應(yīng)礦車(chē)運(yùn)行的狀況，編程時(shí)將位置檢測(cè)程序 置于自動(dòng)控制擋車(chē)欄首位指令之前。位置檢測(cè)系統(tǒng)需要完成的功

12、能是將礦車(chē)的運(yùn)行速度檢測(cè)計(jì)算出來(lái)。圖2-4為位置檢測(cè)系統(tǒng)邏輯流程。圖2-4 位置檢測(cè)流程圖7擋車(chē)欄系統(tǒng)煤礦礦車(chē)防跑車(chē)系統(tǒng)開(kāi)啟和關(guān)閉是是煤礦礦車(chē)防跑車(chē)系統(tǒng)軟件的核心部分。礦車(chē)在斜坡運(yùn)行過(guò)程中，PLC根據(jù)檢測(cè)出的礦車(chē)運(yùn)行速度和用戶設(shè)定的值進(jìn)行對(duì)比，當(dāng)?shù)V車(chē)速度超過(guò)設(shè)定值時(shí)，擋車(chē)欄鋼絲繩網(wǎng)提升開(kāi)啟，防止跑車(chē)造成的事故，反之關(guān)閉。經(jīng)過(guò)仔細(xì)的調(diào)研、分析，設(shè)計(jì)出自動(dòng)開(kāi)啟和關(guān)閉擋車(chē)欄動(dòng)作的邏輯流程圖，如圖2-5所示圖2-5 煤礦礦車(chē)防跑車(chē)系統(tǒng)功能圖在自動(dòng)擋車(chē)欄控制入口處，需滿足一系列的條件才能啟動(dòng)礦車(chē)，礦車(chē)開(kāi)始運(yùn)行進(jìn)入 自動(dòng)控制流程。圖2-6為絞車(chē)啟動(dòng)條件。圖2-6 礦車(chē)啟動(dòng)條件在自動(dòng)控制擋車(chē)欄程序中必需考慮

13、的另一個(gè)方面是礦車(chē)停止運(yùn)行的條件， 當(dāng)正常的絞車(chē)停止或者手動(dòng)按下停止按鈕，或者遇到一些故障情況，程序?qū)⒆詣?dòng)停止絞車(chē)工作。圖2-7為絞車(chē)停止條件，圖中滿足任意條件時(shí)，絞車(chē)將停止工作。圖2-7 礦車(chē)停止條件8 聲光語(yǔ)音報(bào)警系統(tǒng)圖2-8 報(bào)警系統(tǒng)邏輯流程圖圖 2-8為報(bào)警系統(tǒng)流程圖，其功能是將礦車(chē)跑車(chē)后，將故障發(fā)送至監(jiān)控平臺(tái)，并語(yǔ)音提示，減少人身設(shè)備傷亡。 結(jié)束語(yǔ)本設(shè)計(jì)完成的基于PLC的煤礦礦車(chē)防跑車(chē)系統(tǒng)能夠完成以下工作內(nèi)容：1能夠有效的對(duì)擋車(chē)欄進(jìn)行控制，分為手動(dòng)控制和自動(dòng)控制兩種方式；2能夠?qū)ΦV車(chē)的運(yùn)行狀態(tài)進(jìn)行實(shí)時(shí)監(jiān)控，當(dāng)?shù)V車(chē)運(yùn)行出現(xiàn)問(wèn)題時(shí)可及時(shí)報(bào)警并控制擋車(chē)欄對(duì)礦車(chē)進(jìn)行攔截；本設(shè)計(jì)成果也存在一些

14、問(wèn)題，由于條件所限，本次設(shè)計(jì)只能完成模擬實(shí)驗(yàn)，如運(yùn)用在實(shí)際中，電壓穩(wěn)定、工作環(huán)境等都可能對(duì)系統(tǒng)產(chǎn)生影響，造成系統(tǒng)出現(xiàn)一些誤差。需要進(jìn)一步改善。由于本人經(jīng)驗(yàn)和能力有限，對(duì)系統(tǒng)設(shè)計(jì)所需軟硬件的使用還不能達(dá)到駕輕就熟的程度，所以設(shè)計(jì)的程序也只能基本上達(dá)到設(shè)計(jì)要求。 參考文獻(xiàn) 1陳立定. 電氣控制與可編程序控制器的原理及應(yīng)用M. 北京：機(jī)械工業(yè)出版社，2005.1. 2楊長(zhǎng)能等可編程控制器（PC）基礎(chǔ)及應(yīng)用M重慶大學(xué)出版社，1992. 3何衍慶可編程控制器原理及應(yīng)用技巧M北京：化學(xué)工業(yè)出版社，1998. 4王晨，賈福音等斜井跑車(chē)保護(hù)裝置的研究現(xiàn)狀與發(fā)展趨勢(shì)J煤礦機(jī)械，2010，31(3). 5陳拓其一

15、種新型礦車(chē)防跑車(chē)機(jī)構(gòu)的設(shè)計(jì)與仿真J礦山機(jī)械，2009，37(17)：38-40請(qǐng)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 seven-day Chinese請(qǐng)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 easi

16、est way to ruin how you feel about a place and you may become 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 w

17、ill 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 accommodation prices, with the possibility that there will be no rooms available. It is also common that you' ll wait in

18、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 week-long holiday in October. Traveling during this period is a matter that needs thorough preparation. If you a

19、re short on time to plan the upcoming "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

20、seasons. Bestowed by nature, its spectacular seasonal landscape and mountains are just beyond word. Arxan is a crucial destination for the recommended travelling route, "China Inner Mongolia Arxan Hailar Manzhouli". It is also the joint of the four prairies across the Sino-Mongolian border

21、, 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 gorgeous colors all the year round - the S

22、pring 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 Autonomou

23、s 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 uniq

24、ue ecotourism base filled with healthy sunshine, clean air and unspoiled green.  Nestled close to the country'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

25、 of Arxan. It is definitely the best with brightly-colored scenery full of emotions.  Autumn in the northern part of the country comes 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. 

26、0;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 fi

27、nd 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 it's time for the wild fruits to ripe. The picturesque Arxan in Autumn is indeed a fairyland only exists in a dream that satisfies all

28、your fantasies. If it rains heavily on Saturday night, some elderly Chinese will say it is because Zhinu, or the Weaving Maid, is crying on the day she met her husband Niulang, or the Cowherd, on the Milky Way. Most Chinese remember being told this romantic tragedy when they were children on Qi

29、xi, or the Seventh Night Festival, which falls on the seventh day of the seventh lunar month, which is usually in early August. This year it falls on Saturday, August 2. Folklore Story As the story goes, once there was a cowherd, Niulang, who lived with his elder brother and sister-in-law. But she d

30、isliked and abused him, and the boy was forced to leave home with only an old cow for company. The cow, however, was a former god who had violated imperial rules and was sent to earth in bovine form. One day the cow led Niulang to a lake where fairies took a bath on earth. Among them was Zhinu, the

31、most beautiful fairy and a skilled seamstress. The two fell in love at first sight and were soon married. They had a son and daughter and their happy life was held up as an example for hundreds of years in China. Yet in the eyes of the Jade Emperor, the Supreme Deity in Taoism, marriage between a mo

32、rtal and fairy was strictly forbidden. He ordered the heaven troop to catch Zhinu back. Niulang grew desperate when he discovered Zhinu had been taken back to heaven. Driven by Niulang's misery, the cow told him to turn its hide into a pair of shoes after it died. The magic shoes whisked Niulang

33、, who carried his two children in baskets strung from a shoulder pole, off on a chase after the empress. The pursuit enraged the empress, who took her hairpin and slashed it across the sky creating the Milky Way which separated husband from wife. But all was not lost as magpies, moved by their love

34、and devotion, formed a bridge across the Milky Way to reunite the family. Even the Jade Emperor was touched, and allowed Niulang and Zhinu to meet once a year on the seventh night of the seventh month. This is how Qixi came to be. The festival can be traced back to the Han Dynasty (206 BC-AD 220). T

35、raditionally, people would look up at the sky and find a bright star in the constellation Aquila as well as the star Vega, which are identified as Niulang and Zhinu. The two stars shine on opposite sides of the Milky Way. Customs In bygone days, Qixi was not only a special day for lovers, but also f

36、or girls. It is also known as the "Begging for Skills Festival" or "Daughters' Festival." In this day, girls will throw a sewing needle into a bowl full of water on the night of Qixi as a test of embroidery skills. If the needle floats on top of the water instead of sinking,

37、it proves the girl is a skilled embroiders. Single women also pray for finding a good husband in the future. And the newly married women pray to become pregnant quickly. Tradition transformed The love story of Niulang and Zhinu, and the Qixi Festival have been handed down for generations. Yet these

38、ancient traditions and customs are slowly dying out. Many modern Chinese, particularly youngsters, seem to know more about St Valentine's Day on February 14, characterized by bouquets of roses, chocolates and romantic candlelight dinners, than they do about their home-grown day for lovers. Even

39、Qixi is nowadays referred to as the "Chinese Valentine'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 eith

40、er side of the Milky Way, that is, if people even know on which day Qixi falls. There are ready reminders dotted about, in the form of big ads saying "Sales on Chinese Valentine's Day!" in shops, hotels and restaurants. But few young women will mark the festival with their boyfriends,

41、or take part in traditional activities to pray for cleverness. A large-scale 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 exhibit

42、ion 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 o

43、f 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 2009 the second year I was in my school and it was the first

44、 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

45、 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 become 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 i

46、s 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

47、 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 its 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 tha

48、nked 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 complained about it unconsciously.

49、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, become my wife. You are the only girl who I really want to spend the

50、 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 common interests and the common understanding brought us

51、 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 whats 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 others 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