時(shí)間:2022-09-21 06:43:32
導(dǎo)語(yǔ):在長(zhǎng)城介紹的撰寫(xiě)旅程中,學(xué)習(xí)并吸收他人佳作的精髓是一條寶貴的路徑,好期刊匯集了九篇優(yōu)秀范文,愿這些內(nèi)容能夠啟發(fā)您的創(chuàng)作靈感,引領(lǐng)您探索更多的創(chuàng)作可能。
1、長(zhǎng)城(The Great Wall),又稱(chēng)萬(wàn)里長(zhǎng)城,是中國(guó)古代的軍事防御工事,是一道高大、堅(jiān)固而且連綿不斷的長(zhǎng)垣,用以限隔敵騎的行動(dòng)。長(zhǎng)城不是一道單純孤立的城墻,而是以城墻為主體,同大量的城、障、亭、標(biāo)相結(jié)合的防御體系。
2、長(zhǎng)城修筑的歷史可上溯到西周時(shí)期,發(fā)生在首都鎬京(今陜西西安)的著名的典故“烽火戲諸侯”就源于此。春秋戰(zhàn)國(guó)時(shí)期列國(guó)爭(zhēng)霸,互相防守,長(zhǎng)城修筑進(jìn)入第一個(gè),但此時(shí)修筑的長(zhǎng)度都比較短。秦滅六國(guó)統(tǒng)一天下后,秦始皇連接和修繕戰(zhàn)國(guó)長(zhǎng)城,始有萬(wàn)里長(zhǎng)城之稱(chēng)。明朝是最后一個(gè)大修長(zhǎng)城的朝代,今天人們所看到的長(zhǎng)城多是此時(shí)修筑。
3、長(zhǎng)城資源主要分布在河北、北京、天津、山西、陜西、甘肅、內(nèi)蒙古、黑龍江、吉林、遼寧、山東、河南、青海、寧夏、新疆等15個(gè)省區(qū)市。其中河北省境內(nèi)長(zhǎng)度2000多千米,陜西省境內(nèi)長(zhǎng)度1838千米。根據(jù)文物和測(cè)繪部門(mén)的全國(guó)性長(zhǎng)城資源調(diào)查結(jié)果,明長(zhǎng)城總長(zhǎng)度為8851.8千米,秦漢及早期長(zhǎng)城超過(guò)1萬(wàn)千米,總長(zhǎng)超過(guò)2.1萬(wàn)千米。
4、1961年3月4日,長(zhǎng)城被國(guó)務(wù)院公布為第一批全國(guó)重點(diǎn)文物保護(hù)單。1987年12月,長(zhǎng)城被列入世界文化遺產(chǎn)。
(來(lái)源:文章屋網(wǎng) )
1:長(zhǎng)城介紹導(dǎo)游詞英文
Everybody is good! Welcome to badaling scenic area tourism.
The Great Wall is one of the seven wonders of the world. It is the blood of the working people in ancient China, is also a symbol of ancient Chinese culture and the pride of the Chinese nation. Visitors, we have come to the famous badaling Great Wall, on both sides of the mountain, is the pine and cypress, like hidden-away east, birds sounds, gurgling streams, is full of poetic. To the distance, you can see the Great Wall is divided into south and north two peak, winding in the mountain ridges, long teng hu yue, spectacular, the scenery is very spectacular. The Great Wall built around the mountain, ups and downs, twists and turns. This period of the Great Wall of the wall is made of neat huge stone is some stone for up to 2 meters, weighing hundreds of pounds. Internal fill soil and stones, to the top of the wall where the ground covered square brick, very smooth. The wall of the lateral horse-refraining pits of building has 2 meters high, and have made a in, next shot mouth, for look and shooting. Every city wall, built a fortress of square ChengTai type. ChengTai have high low and high called the enemy, is the watchman sergeant and accommodation; Low called Taiwan, height and the wall was similar but prominent wall, have the crenel around, is where the patrol.
Badaling at an altitude of 1000 meters, the twists and turns of the Great Wall, such as the dragon take off on the mountains. It is not only a hardworking, the crystallization of the wisdom of the Chinese nation, is also an excellent representative of ancient architecture engineering. The badaling Great Wall, the distant, rolling hills, XiongChen, stiffness of the north to the mountain. Due to the Great Wall and grand Great Wall for to the mountain, to the mountain is more dangerous.
Here are the beacon tower, also known as beacons, Wolf yantai. Independent buildings is not connected to the Great Wall. Once the enemy pounce, communicate its kindle wars and light smoke during the day is called "ran, called flint fire at night. When the Ming dynasty, also on the relationship between the war with the enemy made a strict rules: the enemy hundreds, burning a smoke point a gun; Five hundred people, burning two smoke point two guns; More than one thousand people, three smoke SAN pao; More than five thousand people, four smoke four guns; More than ten thousand people, five five gun smoke. In this way, on the border of the military intelligence can rapid transfer to the imperial city ouchi. See the beacon tower, and then tell you a story, called "must play leud" : the zhou dynasty had a king named weeks you king, he has a beautiful woman, her temper is very strange, always don't smile, think of some way to you king. He lit up a distress signal (fire), as a result, drew leud come white, she laughed, you king is also very happy. But, really have an enemy to attack, you king lit the fire, but no one come, and he was killed by the enemy. There is a story, called "meng jiangnu cry Great Wall collapse" : legend was Meng Gusheng a daughter named meng jiangnu. Because of qin shi huang to build the Great Wall, need a lot of manpower. Qin shi huang was caught many people go to the Great Wall.
All of a sudden, I do not know where to come up to a rumor: only the wan xi is buried under the Great Wall, can make the Great Wall and solid, qin shi huang was, sent people seize wan xi. Wan xi good fled to Bangladesh. People see wan xi meng home good handsome, talented, good let meng jiangnu and wan xi of their marriage. The two men marry less than 10 days, good wan xi is the rulers who grasp to go to repair the Great Wall. In the fall, meng jiangnu saw her husband hasn't come back, give him the woolies. Along the way, reject, hardships, day and night, all the way to the Great Wall. Local people told her: wan xi good would have buried under the wall. She was grief-stricken, crying. Instantly, and dark, the Great Wall was crying collapsed in eight hundred. Just then, qin shi huang to have the Great Wall, with fine features, when he saw meng jiangnu just want her to do concubine. For qin shi huang meng jiangnu agree to her three conditions: one is for wan xi is a grave; The second is to make good full chao wenwu festivals wan xi; Three is in the middle of the Great Wall and the tomb of wan xi good repair a like flying grand bridge. After three things done, she threw herself into the sea.
Visitors, this is three stories about the Great Wall. Now the Great Wall tourist stop here, thank you!
2:長(zhǎng)城介紹導(dǎo)游詞英文
Good morning! My name is Chen Ying snow, carefree travel guide, today is a great pleasure to serve you, you can call me snow! Today we are going to visit the Great Wall of landscape is famous in the world. The Great Wall is the world's precious historical relics, hope everyone to love the Great Wall, don't litter scribble, oh!
The Great Wall has a long history, a history of more than 2000 years, the spring and autumn period and the warring states period, the warring states to mutual defense, has built the Great Wall in the dangerous place. According to records zuozhuan: in 656 BC, "chu mahjong layout" is about the earliest record of the Great Wall. Out the six nations after the unification of China, qin to defense the north south invasion of the huns, in 224 BC, the qin, zhao and yan in The Three Kingdoms of the north Great Wall, re-hung, coherent rise. Some west about (now min county, gansu province) north mountain, east to liaodong, which is commonly known as the "Great Wall", still remains. Since then, the han, the northern wei dynasty, their, beiqi, sui dynasties had built the Great Wall. The composition
In Ming dynasty, in order to defense the invasion of alien, built the Great Wall before and after 18 times, total length of 6700 km, east of shanhaiguan, west to jiayuguan, today we visit this section of the Great Wall is built in the Ming dynasty, is located in the badaling.
Now we have arrived at the foot of badaling. Tourists friends, please look up at the Great Wall: it is like a huge dragon, winding between mountains. Please follow me to the Great Wall, see: every three hundred meters on the walls of the Great Wall there is a square ChengTai, is an ancient fortress to station troops. It is said that war, between the ChengTai can mutual echo. On the top of the walls are covered with very flat square brick, like a wide road, probably ErSanTai car can be parallel. Outside the wall along with many more than two meters high, the rows of the crenel, for? With hope and shot. The composition
My friends, have a look at your feet? Guess what weigh? Tell you! This is a stone, a piece of have two or three one thousand catties! At that time, there is no train, automobile, also have no crane, is by the shoulder of countless countless hands, step by step, carry on the steep mountains. This is how many working people sweat and wisdom, to condense into the former does not see the head, after see the tail of the Great Wall!
This is the Great Wall! This is the west jiayuguan, east to shanhaiguan, which meet the sea sunrise and gobi desert sun, or turned on the peaks, or bent over in the valley, the ups and downs, stretching thousands of miles of the Great Wall. It is such a magnificent verve, Great Wall is a great miracle in the history of the world!
Dear visitors, today's visit here will be over, thank you very much for my support and cooperation. The majestic Great Wall forever awaits respectfully you the presence!
3:長(zhǎng)城介紹導(dǎo)游詞英文
Everybody is good! Welcome to badaling scenic area tourism. Accompany you visit together, today I am very happy, hope all can spend a good time in badaling.
Right now, I would go to visit the door
Badaling Great Wall, and now, I'll about matters needing attention: the Great Wall is one of the famous wonders of the world, it is like a dragon entrenched in north China's vast land. It is the crystallization of labor people's blood law in ancient China, is also a symbol of ancient Chinese culture and the pride of the Chinese nation, please don't scribble on the brick fluidized.
Visitors, now we have come to the famous badaling Great Wall, to the distance, you can see the Great Wall is divided into south and north two peak, winding in the mountain ridges, long teng hu yue, spectacular, the scenery is very spectacular. Look here is a two openings and u-shaped walls satin afraid brought to the barbican. Both inside and outside the barbican wall on both sides have the crenel wall, all defensive ring. If the enemy breached close into the city, will have been all around guarding city will panic in the enemy like fall in the urn. The barbican is an important part of the Great Wall. It is generally built on terrain dangerous traffic arteries. Badaling the barbican is no exception. Built on the ridge, restricted by terrain, mountain potential, low west high east, east narrow width, only 5000 square meters. There is no hole in the barbican, lack of water, usually few troops, guarding city forces in the northwest three mile fork city. Barbican in a "examine the courtyard mansion", the original is stay accommodation for the emperor passed in or officials. Barbican 63.9 meters apart, between the two door XiMenMei TiE "north gate lock-and-key", it meant I have spoken in front.
City on the doorway, ancient into install a huge double wooden door, door installation has wooden needle and latches. At ordinary times, both doors open and the pedestrian travel free access; Wartime gate closed, sealed hard; Once struck back order, city door is the export of hammering dashed forward. Barbican east gate lintel TiE as "the agent to fill", built during Ming jiajing eighteen years. Town "outside" the commonplace GuanCheng city on the stage, the original is embedded with a piece of stone, is the Ming wanli years of print. From the inscriptions could look around the Great Wall, has the more than 80 years time to complete. This tablet is a record of construction time, length of the Great Wall and the officer and tube foreman, burning head, head of the potter, mason head and name, in order to make clear the responsibility. Stand to look down on the city, we see in constant traffic and visitors through the door. Here is not only an important military defense of the ancient barrier, but also traffic arteries. From here, nantong changping, Beijing, north to yanqing, northwest to xuanhua, zhangjiakou, "convenient way from now on,". Badaling is hence the name.
When we came to linhai Great Wall, at the foot of the Great Wall, look up, the endless winding high steps, as if is a path to a blue sky of the ladder, and he seems like a dragon hou lie in rolling peaks.
Along the stairs up, came to the first gate "range gate", the ancient scene immediately appear at present, the gate is a two layers of ancient buildings, two sides of the ancients of flags fluttering, increased the antique appeal. The second floor is "clearly" lake mountain, standing there, "the east lake park" as a painting, panoramic view, I'd like to bring a "lake mountain" may be just that.
The walk, we came to the second gate "Gu Jing floor", standing on the roof of almost half of linhai city is clearly visible. Go up again, we finally boarded the highest floor of the Great Wall "Bai Yunlou", "finally finished!" I shouted happily. Standing on the "Bai Yunlou", panoramic view of the city, you see the white tower is the tallest building in linhai city, the distance of the "white band" is the yongning river to the sea.
2、然后就是叫物料員去倉(cāng)庫(kù)領(lǐng)用物料,俗稱(chēng)備料。
3、準(zhǔn)備好物料以后,接著準(zhǔn)備相應(yīng)的工作夾具,作業(yè)指導(dǎo)書(shū),如果是第一次生產(chǎn)的話(huà),還要通知相關(guān)技術(shù)人員到現(xiàn)場(chǎng)指導(dǎo)。
4、物料都就緒以后,然后就安排生產(chǎn)人員進(jìn)行生產(chǎn)。
5、將成品生產(chǎn)出來(lái)以后,再然后就是OQC品管進(jìn)行質(zhì)量檢查,檢查沒(méi)有問(wèn)題以后進(jìn)行包裝。
【關(guān)鍵詞】脫硝技術(shù) 工藝選擇 SCR脫硝 脫硝設(shè)計(jì)
中圖分類(lèi)號(hào):TG333.7 文獻(xiàn)標(biāo)識(shí)碼:A 文章編號(hào):1009-914X(2013)35-266-01
1. 前言
我國(guó)是以燃煤為主的發(fā)展中國(guó)家,其能源構(gòu)成以煤炭為主,消耗量占一次能源消費(fèi)量的76%左右。隨著經(jīng)濟(jì)的快速發(fā)展,煤耗的增加,燃煤造成的大氣污染日趨嚴(yán)重,特別是燃煤煙氣中的氮氧化物(NOx),是大氣污染的主要污染物之一。據(jù)統(tǒng)計(jì),我國(guó)大氣污染物中NOx 60 %來(lái)自于煤的燃燒,其中火電廠(chǎng)發(fā)電用煤又占了全國(guó)燃煤的70%。2000 年我國(guó)火電廠(chǎng)氮氧化物排放量控制在500萬(wàn)t 左右,按照目前的排放控制水平,到2020年,氮氧化物排放量將達(dá)到1000萬(wàn)t 以上。NOx對(duì)大氣的污染已成為一個(gè)不容忽視的重要問(wèn)題,控制和治理氮氧化物污染已迫在眉睫。燃煤煙氣脫氮稱(chēng)為煙氣脫硝,脫硝是控制NOx污染的一個(gè)重要途徑。近年來(lái)國(guó)內(nèi)外研究開(kāi)發(fā)了一系列燃煤煙氣脫硝技術(shù),并取得了一定成果。
2. 煙氣脫硝技術(shù)的介紹
煙氣脫硝技術(shù)按治理工藝可分為濕法脫硝和干法脫硝。濕法脫硝包括:酸吸收法、堿吸收法、氧化吸收法、絡(luò)鹽吸收法等;干法脫硝主要有:選擇性催化還原法、非選擇性催化還原法、等。此外,近十幾年來(lái)國(guó)內(nèi)外一些科研人員還開(kāi)發(fā)了用微生物來(lái)處理含NOX廢氣,成為研究的熱點(diǎn)。
2.1 濕法煙氣脫硝技術(shù)
濕法煙氣脫硝是利用液體吸收劑將NOx溶解的原理來(lái)凈化燃煤煙氣,其最大的障礙是NO很難溶于水,往往要求將NO首先氧化為NO2。為此一般先將NO通過(guò)與氧化劑O3 、ClO2或KMnO4反應(yīng),氧化生成NO2,然后NO2被水或堿性溶液吸收,實(shí)現(xiàn)煙氣脫硝。
濕法脫硝技術(shù)優(yōu)點(diǎn):脫硝效率較高;因吸收劑種類(lèi)較多,來(lái)源廣泛,適應(yīng)性強(qiáng);能以硝酸鹽等形式回收NOX,可達(dá)到綜合利用的目的。缺點(diǎn)是其技術(shù)比較復(fù)雜,設(shè)備容量大不易建造,成本較高,而且易造成溶液的二次污染。
2.2 干法脫硝技術(shù)
與濕法相比,干法凈化處理含NOX尾氣的主要優(yōu)點(diǎn)是:設(shè)備及工藝過(guò)程簡(jiǎn)單,脫除NOX的效率也較高,無(wú)廢水和廢棄物處理,不易造成二次污染。
2.2.1 選擇性催化還原(SCR)脫硝
SCR脫硝原理是利用NH3和催化劑(鐵、釩、鉻、鈷或鉬等堿金屬)在溫度為200~450℃時(shí)將NOX還原為N2。NH3具有選擇性,只與NOX發(fā)生反應(yīng),基本上不與O2反應(yīng),所以稱(chēng)為選擇性催化還原脫硝。
SCR法是國(guó)際上應(yīng)用最多,技術(shù)最成熟的一種煙氣脫硝技術(shù)。在歐洲已有120多臺(tái)大型的SCR裝置的成功應(yīng)用經(jīng)驗(yàn),其N(xiāo)OX的脫除率達(dá)到80%~90%;日本大約有170套SCR裝置,接近100000MW容量的電廠(chǎng)安裝了這種設(shè)備;美國(guó)政府也將SCR技術(shù)作為主要的電廠(chǎng)控制NOX技術(shù)。
該法的優(yōu)點(diǎn)是:由于使用了催化劑,故反應(yīng)溫度較低;凈化率高,可達(dá)85%以上;工藝設(shè)備緊湊,運(yùn)行可靠;還原后的氮?dú)夥趴眨瑹o(wú)二次污染。但也存在一些缺點(diǎn):煙氣成分復(fù)雜,某些污染物可使催化劑中毒;高分散的粉塵微粒可覆蓋催化劑的表面,使其活性下降;系統(tǒng)中存在一些未反應(yīng)的NH3和煙氣中的SO2作用,生成易腐蝕和堵塞設(shè)備的(NH4)2SO4和NH4HSO4,同時(shí)還會(huì)降低氨的利用率;投資與運(yùn)行費(fèi)用(投資費(fèi)用80美元/千瓦)較高。
2.2.2 非選擇性催化還原(SNCR)脫硝
與SCR法相比,SNCR法除不用催化劑外,基本原理和化學(xué)反應(yīng)基本相同。SNCR法通過(guò)在煙道氣中產(chǎn)生的氨自由基與NOX反應(yīng),以去除NOX。因沒(méi)有催化劑作用,反應(yīng)所需溫度較高(900~1200℃),溫度控制是關(guān)鍵,以免氨被氧化成氮氧化物。
該法的優(yōu)點(diǎn)是不需催化劑,投資較SCR法小(投資費(fèi)用15美元/千瓦)。但氨液消耗量大,NOX的脫除率也不高。目前大部分鍋爐都不采用此法,主要原因是:(1)效率不高;(2)反應(yīng)劑和運(yùn)載介質(zhì)(空氣)的消耗量大;(3)氨的泄漏量大;(4)生成的(NH4)2SO4和NH4HSO4會(huì)腐蝕和堵塞設(shè)備。
2.3 微生物法脫氮
采用微生物凈化含NOX廢氣的凈化機(jī)理是:適宜的脫氮菌在有外加碳源的情況下,利用NOX作為氮源,將NOX還原為最基本無(wú)害的氮?dú)猓摰旧慝@得生長(zhǎng)繁殖。其中NO2先溶于水中形成NO3-及NO2-,然后被微生物還原為氮?dú)?,煙氣中的NO則直接被吸附在微生物表面還原為氮?dú)狻?/p>
用微生物進(jìn)行廢氣脫硝能有效地脫除廢氣中的NOX,具有工藝簡(jiǎn)單、能耗和處理費(fèi)用低、效率高、無(wú)二次污染等優(yōu)點(diǎn)。但要實(shí)現(xiàn)工業(yè)應(yīng)用還存在一些問(wèn)題:(1)微生物的生長(zhǎng)速度相對(duì)較慢,要處理大流量的煙氣,還需對(duì)菌種作進(jìn)一步的篩選;(2)微生物的生長(zhǎng)需適宜的環(huán)境;(3)微生物的生長(zhǎng)會(huì)造成塔內(nèi)填料的堵塞。
3. 火電廠(chǎng)脫硝工程的工藝選擇
通過(guò)上述主要脫硝技術(shù)介紹可以看出,SCR技術(shù)對(duì)煙氣NOx的控制效果十分顯著,它具有工作溫度低,技術(shù)成熟可靠,易于操作,脫硝效率高等優(yōu)點(diǎn),是目前世界唯一大規(guī)模投入商業(yè)應(yīng)用并能滿(mǎn)足日益嚴(yán)峻環(huán)保要求的控制措施,非常適合應(yīng)用于大中型火力發(fā)電廠(chǎng)脫硝工程。
4. SCR煙氣脫硝工程實(shí)例
某發(fā)電廠(chǎng)二期工程2×660MW國(guó)產(chǎn)超臨界燃煤汽輪發(fā)電機(jī)組機(jī)組,響應(yīng)國(guó)家節(jié)能減排號(hào)召,嚴(yán)格執(zhí)行環(huán)保排放標(biāo)準(zhǔn),3號(hào)爐同步建設(shè)煙氣脫硝裝置,4號(hào)爐考慮預(yù)留煙氣脫硝裝置,配套脫硝工藝為浙江融智能源科技有限公司的選擇性催化還原法(SCR),并由其設(shè)計(jì)、供貨。
4.1工藝流程
3號(hào)爐煙氣脫硝裝置配置兩個(gè)脫硝反應(yīng)器, 一套氨儲(chǔ)存、蒸發(fā)、供應(yīng)系統(tǒng),氨區(qū)設(shè)計(jì)考慮4號(hào)爐預(yù)留脫硝還原劑供應(yīng),煙氣從鍋爐省煤器出來(lái)后進(jìn)入脫硝進(jìn)口煙道,在此位置處通過(guò)氨噴射格柵噴入氨氣與煙氣進(jìn)行混合。含有氨氣的煙氣進(jìn)入脫硝反應(yīng)器,在反應(yīng)器中完成脫硝反應(yīng),經(jīng)脫硝后的煙氣進(jìn)入空氣預(yù)熱器,經(jīng)除塵、脫硫凈化處理后排入大氣。本脫硝裝置不設(shè)置旁路。
脫硝還原劑氨氣是由液氨儲(chǔ)罐中液氨經(jīng)液氨蒸發(fā)器加熱蒸發(fā)產(chǎn)生純氨氣,與稀釋風(fēng)機(jī)提供的空氣在混合氣中混合稀釋后,噴入脫硝煙道中。
脫硝裝置采用板式催化劑,板間距為6mm,這種催化劑不易堵塞。由于脫硝裝置為高塵布置,在運(yùn)行過(guò)程催化劑表面會(huì)積灰,需采用聲波吹灰器進(jìn)行定期吹掃。每層催化劑均設(shè)置聲波吹灰器,壓縮空氣取自鍋爐。
4.2系統(tǒng)設(shè)計(jì)
本脫硝系統(tǒng)主要設(shè)計(jì)參數(shù)如表1所示。
本煙氣脫硝工程設(shè)計(jì)主要分三部分:SCR本體設(shè)計(jì)部分;氨區(qū)設(shè)計(jì)部分;輔助系統(tǒng)設(shè)計(jì)部分。
4.2.1、SCR本體設(shè)計(jì)部分
本工程脫硝系統(tǒng)設(shè)計(jì)脫硝效率為80%。SCR催化劑按2+1方式布置(即初始布置二層,預(yù)留一層)。系統(tǒng)不設(shè)置SCR裝置旁路和省煤器高溫旁路。SCR裝置設(shè)置檢修、測(cè)試平臺(tái), SCR系統(tǒng)主要設(shè)備如下:
A)、SCR反應(yīng)器:每臺(tái)爐設(shè)置兩臺(tái)反應(yīng)器,反應(yīng)器的長(zhǎng)、寬、高分別為:12m、12m和12.6m.
B)、吹灰系統(tǒng):反應(yīng)器每層催化劑設(shè)置3臺(tái)聲波吹灰器,吹灰介質(zhì)為檢修用壓縮空氣,壓力為0.45~0.7MPa。每臺(tái)吹灰器的單位時(shí)間空氣耗量為6Nm3/min,吹掃頻率為72次/h。
C)、灰斗:在每個(gè)SCR脫硝出口煙道處設(shè)置3個(gè)灰斗,以收集大顆粒飛灰,防止其隨煙氣進(jìn)入空預(yù)器。
D)、催化劑:采用板式催化劑,活性溫度為300~420℃,催化劑間距為6mm。催化劑基材為不銹鋼材質(zhì),活性物質(zhì)為T(mén)iO2、釩化合物等。催化劑化學(xué)壽命為24000h。
4.2.2氨區(qū)設(shè)計(jì)部分
脫硝還原劑采用液氨。液氨儲(chǔ)存、制備、供應(yīng)系統(tǒng)包括液氨卸料壓縮機(jī)、液氨儲(chǔ)罐、液氨蒸發(fā)器、氨氣緩沖罐、氨氣稀釋槽、廢水泵等。
氨區(qū)占地面積為24m×21.6m。主要設(shè)備規(guī)范見(jiàn)表2:
4.2.3輔助系統(tǒng)設(shè)計(jì)
壓縮空氣系統(tǒng):從鍋爐壓縮檢修用空氣母管、儀用壓縮空氣母管接出。
蒸汽系統(tǒng):蒸發(fā)液氨所需的蒸汽從鍋爐蒸汽管道上接出。
4.3 脫硝系統(tǒng)的運(yùn)行
4.3.1氨氣流量控制
液氨經(jīng)過(guò)蒸發(fā)器產(chǎn)生脫硝所需氨氣(濃度為100%),在混合器中被空氣稀釋成5%(體積比例)濃度以下,然后噴入煙道中進(jìn)行反應(yīng)。為保證進(jìn)入脫硝煙道氨氣濃度在5%以下,稀釋風(fēng)量按最大氨耗量時(shí)所需空氣流量設(shè)計(jì),并在運(yùn)行時(shí)保持空氣流量不變。
運(yùn)行過(guò)程中氨耗量需根據(jù)反應(yīng)器進(jìn)出口煙氣中NOx濃度來(lái)調(diào)整控制。脫硝系統(tǒng)設(shè)有停止噴氨煙氣溫度、最低噴氨煙氣溫度、最高連續(xù)運(yùn)行溫度,當(dāng)煙氣溫度低于最低噴氨溫度或高于最高連續(xù)運(yùn)行溫度時(shí),需停止噴氨。
4.3.2吹灰控制
吹灰系統(tǒng)采用聲波吹灰方式,吹灰器的數(shù)量為3臺(tái)/層,能將催化劑中的積灰盡可能多地吹掃干凈,此種吹灰方式可避免因死角而造成催化劑失效導(dǎo)致脫硝效率的下降和反應(yīng)器煙氣阻力的增加。每一層催化劑吹灰的順序?yàn)槊繉用看芜\(yùn)行一臺(tái)聲波喇叭,每組每次運(yùn)行十秒鐘,每一循環(huán)的間隔為十分鐘。吹灰頻率可根據(jù)反應(yīng)器的壓降進(jìn)行調(diào)整控制。
4.4 實(shí)際運(yùn)行情況
該電廠(chǎng)二期2×660MW機(jī)組3號(hào)爐煙氣脫硝裝置投運(yùn)以來(lái),運(yùn)行穩(wěn)定,未發(fā)生設(shè)備故障。催化劑采用聲波吹灰器吹灰效果良好,催化劑層積灰很少。氨區(qū)系統(tǒng)供氨連續(xù)穩(wěn)定,無(wú)設(shè)備故障,未發(fā)生氨泄漏。煙氣脫硝裝置與鍋爐主機(jī)同步于2009年3月27日下午3點(diǎn)順利通過(guò)168小時(shí)試運(yùn)行,于2010年4月份順利通過(guò)性能試驗(yàn),各項(xiàng)性能指標(biāo)滿(mǎn)足設(shè)計(jì)要求。
在性能試驗(yàn)期間,主要數(shù)據(jù)見(jiàn)表3。
5. 結(jié)束語(yǔ)
選擇性催化還原法(SCR)煙氣脫硝工藝是非常成熟、可靠的工藝,并在火力發(fā)電廠(chǎng)660MW機(jī)組上得到應(yīng)用,該工程脫硝裝置運(yùn)行穩(wěn)定,脫硝裝置的各項(xiàng)性能指標(biāo)均滿(mǎn)足性能要求,SCR煙氣脫硝工藝應(yīng)在大型火力發(fā)電廠(chǎng)脫硝工程上給予推廣應(yīng)用。
參考文獻(xiàn):
[1]王振宇. 燃煤電廠(chǎng)的除塵、脫硫、脫銷(xiāo)技術(shù)[J]. 環(huán)境保護(hù)科學(xué),2005.
[2] 吳忠標(biāo). 大氣污染控制技術(shù)[M]. 北京:化學(xué)工業(yè)出版社,2002.
[3]李曉東,楊卓如. 國(guó)外氮氧化物氣體治理的研究進(jìn)展[J]. 環(huán)境工程,1996.
吉林省遼源礦業(yè)集團(tuán)總醫(yī)院,吉林遼源136200
[摘要]目的探討納米銀敷料結(jié)合重組牛堿性成纖維細(xì)胞生長(zhǎng)因子凝膠治療燒傷殘余創(chuàng)面的臨床效果。方法選取我院自2011年10月—2013年10月收治的76例出現(xiàn)燒傷殘余創(chuàng)面患者隨機(jī)分為觀察組與參考組,各為38例,觀察組患者采用納米銀敷料結(jié)合重組牛堿性成纖維細(xì)胞生長(zhǎng)因子凝膠治療,參考組患者采用無(wú)菌石蠟油紗布聯(lián)合生理鹽水換藥,比較兩組患者創(chuàng)面愈合時(shí)間、感染例數(shù)、治療7d時(shí)創(chuàng)面細(xì)菌培養(yǎng)情況及藥物不良反應(yīng)。結(jié)果參考組患者創(chuàng)面愈合時(shí)間明細(xì)小于觀察組(P<0.05);參考組患者出現(xiàn)13例感染,感染率為34.2%,觀察組患者出現(xiàn)3例感染,感染率為7.9%,數(shù)據(jù)比較有統(tǒng)計(jì)學(xué)意義(P<0.05);參考組患者7d時(shí)創(chuàng)面細(xì)菌檢出率明顯高于觀察組(P<0.05);兩組患者藥物不良反應(yīng)比較無(wú)統(tǒng)計(jì)學(xué)意義(P>0.05)。結(jié)論采用納米銀敷料結(jié)合重組牛堿性成纖維細(xì)胞生長(zhǎng)因子凝膠治療燒傷殘余創(chuàng)面,抗菌作用顯著,能夠促進(jìn)創(chuàng)面修復(fù),值得推廣使用。
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關(guān)鍵詞 ]納米銀敷料;重組牛堿性成纖維細(xì)胞生長(zhǎng)因子凝膠;燒傷殘余創(chuàng)面
[中圖分類(lèi)號(hào)]R446[文獻(xiàn)標(biāo)識(shí)碼]A[文章編號(hào)]1672-5654(2014)05(c)-0160-02
近年來(lái)燒傷患者不斷增加,嚴(yán)重威脅人們健康,燒傷后創(chuàng)面處理不及時(shí)徹底可導(dǎo)致感染、反復(fù)潰爛等,延遲創(chuàng)面愈合。傳統(tǒng)臨床治療中主要采用高滲鹽水及生理鹽水等聯(lián)合外用抗菌素藥物作為換藥藥物,然而仍然存在較高的感染率等,納米銀敷料作為新型敷料,能夠維持創(chuàng)面的動(dòng)態(tài)活性銀,可用于各類(lèi)創(chuàng)口的治療,重組牛堿性成纖維細(xì)胞生長(zhǎng)因子在創(chuàng)面的修復(fù)中效果顯著,為對(duì)二者結(jié)合治療燒傷傷殘余創(chuàng)面的治療效果進(jìn)行探討,筆者對(duì)我院收治的76例出現(xiàn)燒傷殘余創(chuàng)面的患者進(jìn)行研究分析,報(bào)道如下。
1資料與方法
1.1一般資料
我院自2011年10月—2013年10月收治的出現(xiàn)76例(80處創(chuàng)面)燒傷殘余創(chuàng)面患者,男43例,女33例,年齡18~55歲,平均年齡(30.25±4.18)年,創(chuàng)面大小(4.32±0.53)cm2,其中深Ⅱ度44處,Ⅲ度36處,距離治療時(shí)間>21d,熱液燙傷39例,火焰燒傷37例,殘余創(chuàng)面位置:四肢45處,軀體35處,排除出血傾向或出血性疾病、嚴(yán)重心肺肝腎障礙、血液系統(tǒng)疾病及嚴(yán)重感染、并發(fā)癥、病情危重患者,排除糖尿病等代謝性疾病患者,所有患者均無(wú)銀過(guò)敏史,將患者隨機(jī)分為參考組與觀察組,各為38例,兩組患者年齡、病情及性別等比較無(wú)統(tǒng)計(jì)學(xué)意義(P>0.05),可進(jìn)行比較。
1.2方法
使用材料:納米銀敷料(生產(chǎn)公司:深圳市愛(ài)杰特醫(yī)藥科技有有限公司,生產(chǎn)許可:20030851),重組牛堿性成纖維細(xì)胞生長(zhǎng)因子凝膠(生產(chǎn)公司:珠海億勝生物制藥有限公司。國(guó)藥準(zhǔn)字:S20040001)。觀察組:徹底對(duì)創(chuàng)面消毒清理后,采用生理鹽水對(duì)創(chuàng)面進(jìn)行清潔,之后在創(chuàng)面涂抹重組牛堿性成纖維細(xì)胞生長(zhǎng)因子凝膠,每次300IU/cm2,之后敷貼納米銀敷料;參考組:采用生理鹽水對(duì)創(chuàng)面徹底清理后,采用無(wú)菌石蠟油紗布對(duì)創(chuàng)面進(jìn)行包扎,兩組患者均每天換藥1次。
1.3觀察指標(biāo)
對(duì)兩組患者創(chuàng)面愈合時(shí)間進(jìn)行觀察,同時(shí)記錄創(chuàng)面出現(xiàn)的疼痛加重、紅腫、創(chuàng)面膿性分泌物等,在治療7d時(shí)分別對(duì)兩組患者創(chuàng)面細(xì)菌進(jìn)行培養(yǎng),同時(shí)記錄患者藥物不良反應(yīng)發(fā)生情況。
1.4統(tǒng)計(jì)學(xué)分析
本次研究均采用spss18.0統(tǒng)計(jì)學(xué)軟件處理所有患者的臨床資料,采用均數(shù)加減標(biāo)準(zhǔn)差表示(x±s)計(jì)量資料,采用t檢驗(yàn)計(jì)數(shù)資料,采用χ2檢驗(yàn)組間對(duì)比,P<0.05為差異具有統(tǒng)計(jì)學(xué)意義。
2結(jié)果
①參考組患者創(chuàng)面平均愈合時(shí)間為(28.34±6.13)d,觀察組患者創(chuàng)面平均愈合時(shí)間為(19.68±5.28)d,數(shù)據(jù)比較有統(tǒng)計(jì)學(xué)意義(P<0.05)。
②參考組13例患者康復(fù)期間出現(xiàn)創(chuàng)面感染,感染發(fā)生率為34.2%,觀察組3例患者康復(fù)期間出現(xiàn)創(chuàng)面感染,感染發(fā)生率為7.9%,差異有統(tǒng)計(jì)學(xué)意義(P<0.05);治療7d時(shí),參考組患者致病細(xì)菌檢出率明顯高于觀察組,差異有統(tǒng)計(jì)學(xué)意義(P<0.05),詳見(jiàn)表1。
③觀察組患者在治療期間未出現(xiàn)局部或全身過(guò)敏癥狀,無(wú)創(chuàng)面疼痛,患者肝腎、血常規(guī)檢查等均正常,參考組患者治療期間未出現(xiàn)任何不良反應(yīng),數(shù)據(jù)比較無(wú)統(tǒng)計(jì)學(xué)意義(P>0.05)。
3討論
納米銀敷料具有殺菌、抗菌效果,陰離子釋放后,結(jié)合帶負(fù)電荷的菌體蛋白質(zhì),并使其變形沉淀銀同時(shí)與酶的巰基結(jié)合,從而形成穩(wěn)定的硫酸鹽[1],抑制系列巰基的酶活性,將細(xì)菌呼吸酶系統(tǒng)阻斷,對(duì)細(xì)菌代謝進(jìn)行干擾,并最終導(dǎo)致細(xì)菌死亡,從而起到有效的抑菌及殺菌。銀的殺菌機(jī)制與化學(xué)合成的抗菌劑不同,通過(guò)重金屬離子對(duì)細(xì)菌蛋白質(zhì)的變性產(chǎn)生作用,從而具有不易耐藥、廣譜殺菌的作用[2]。納米銀敷料化學(xué)特性穩(wěn)定,能夠與真菌及細(xì)菌的DNA結(jié)合,并促使其結(jié)構(gòu)的改變,使真菌及細(xì)菌活性受到抑制[3]。重組牛堿性成纖維細(xì)胞生長(zhǎng)因子作為生物活性較強(qiáng)的促分裂元,能夠刺激成纖維細(xì)胞、上皮細(xì)胞、血管內(nèi)皮細(xì)胞、真皮細(xì)胞等具有再生及促修復(fù)作用[4]。藥物能夠促進(jìn)內(nèi)皮細(xì)胞分裂,誘導(dǎo)其分泌某些蛋白酶,溶解并侵入周?chē)|(zhì),形成纖維細(xì)胞及毛細(xì)血管,建立側(cè)支循環(huán),促進(jìn)新的毛細(xì)血管網(wǎng)的形成,血液流量、肉芽組織毛細(xì)血管數(shù)量等均明顯增加,創(chuàng)面微循環(huán)有效改善[5]。重組牛堿性成纖維細(xì)胞生長(zhǎng)因子等在創(chuàng)傷、燒傷及慢性潰瘍的治療中能夠有效促進(jìn)傷口愈合,能夠促進(jìn)供皮區(qū)、燒創(chuàng)傷、手術(shù)創(chuàng)面的良好愈合[6]。本次研究中,觀察組患者創(chuàng)面平均愈合時(shí)間明顯短于參考組(P<0.05),患者治療中感染發(fā)生率明顯低于參考組(P<0.05),治療7d后觀察組患者細(xì)菌檢出率明顯低于參考組(P<0.05),由此可見(jiàn),納米銀敷料結(jié)合重組牛堿性成纖維細(xì)胞生長(zhǎng)因子凝膠治療燒傷殘余創(chuàng)面;本次治療中,兩組患者均未出現(xiàn)不良反應(yīng),比較無(wú)統(tǒng)計(jì)學(xué)意義(P>0.05),由此可知,納米銀敷料及重組牛堿性成纖維細(xì)胞生長(zhǎng)因子凝膠在創(chuàng)面治療中均不會(huì)產(chǎn)生嚴(yán)重不良反應(yīng),安全性高,值得推廣使用。
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參考文獻(xiàn)]
[1]李民,牛亞明,林倩君,等.納米銀敷料對(duì)燒傷創(chuàng)面保護(hù)作用的觀察[J].中國(guó)醫(yī)師進(jìn)修雜志,2006,29(5):11-13.
[2]李曉魯,黃躍生,彭毅志,等.納米晶體銀敷料治療燒傷后殘余創(chuàng)面的多中心臨床研究[J].中華燒傷雜志,2006,22(1):15-18.
[3]郭立君,李校堃,許華,等.重組牛堿性成纖維細(xì)胞生長(zhǎng)因子治療Ⅱ度燒傷的臨床療效[J].中國(guó)生物制品學(xué)雜志,2002,12(5):63-64.
[4]王秋春.重組牛堿性成纖維細(xì)胞生長(zhǎng)因子治療Ⅲ期褥瘡的護(hù)理[J].護(hù)理研究,2005,12(11):562-563.
[5]劉族安,夏照帆,唐洪泰,等.重組牛堿性成纖維細(xì)胞生長(zhǎng)因子凝膠對(duì)燒傷創(chuàng)面的療效研究[J].第二軍醫(yī)大學(xué)學(xué)報(bào),2004,12(11):36-37.
想要成為一位合格的小導(dǎo)游,一份精彩、生動(dòng)的導(dǎo)游詞必不可少。導(dǎo)游詞中,既要有對(duì)景區(qū)的整體介紹,也要有對(duì)某個(gè)景點(diǎn)的重點(diǎn)講解,如果還能對(duì)景點(diǎn)名稱(chēng)的由來(lái)侃侃而談,并且巧妙地穿插景觀背后的歷史和故事,引用名人留下的詩(shī)句或?qū)β?lián),就更能激發(fā)游客的興趣了??旄衔业哪_步,打造一份獨(dú)特的導(dǎo)游詞,讓更多的游客進(jìn)一步領(lǐng)略世界文化遺產(chǎn)的藝術(shù)魅力,留下美好的回憶吧!
當(dāng)我們與游客初次見(jiàn)面時(shí),首先應(yīng)向游客問(wèn)好,然后進(jìn)行自我介紹,再說(shuō)歡迎詞,最后告知將會(huì)帶大家去哪一處景點(diǎn),說(shuō)明游覽的目的,最重要的是別忘了帶上你的熱情與禮貌喲!請(qǐng)注意,本次列車(chē)即將到達(dá)旅程的第一站――八達(dá)嶺長(zhǎng)城。
“各位游客大家好,歡迎大家搭乘我們的游覽專(zhuān)列,我是你們的導(dǎo)游。首先,我要祝賀大家即將成為真正的‘好漢’!因?yàn)槲覀兘裉鞂⒌巧习诉_(dá)嶺長(zhǎng)城,真正感受‘不到長(zhǎng)城非好漢’的意境?!?/p>
在游客們準(zhǔn)備下車(chē),開(kāi)始今天的游覽行程之前,小導(dǎo)游不妨先總體介紹這處景點(diǎn)的基本情況,比如它的地理位置在哪兒,它在全國(guó)甚至全世界有什么地位,等等。
“現(xiàn)在,我們的列車(chē)馬上就要進(jìn)入八達(dá)嶺景區(qū)了。大家看,前面的那座就是軍都山,長(zhǎng)城就像一條巨龍盤(pán)踞在這座山上。長(zhǎng)城是中華文化的瑰寶,是世界文化遺產(chǎn)之一,被譽(yù)為世界建筑的奇跡!它東起山海關(guān),西至嘉峪關(guān),是中國(guó)古代人民智慧血汗的結(jié)晶,也是中國(guó)古代文化的象征和中華民族的驕傲。我們今天要參觀的八達(dá)嶺長(zhǎng)城是明代修筑的,它氣勢(shì)磅礴,正是萬(wàn)里長(zhǎng)城的精華?!?/p>
當(dāng)游客步入景區(qū)時(shí),導(dǎo)游的核心任務(wù)就是向他們展示這一景區(qū)的最大魅力與特色,并重點(diǎn)介紹幾處著名的風(fēng)光或景觀。簡(jiǎn)單來(lái)說(shuō),我們可以按照游覽順序,對(duì)所選景觀逐一進(jìn)行生動(dòng)的、具體的描述和解說(shuō),使游客盡情覽景點(diǎn)風(fēng)光。
“朋友們,我們現(xiàn)在已經(jīng)來(lái)到了長(zhǎng)城腳下,請(qǐng)大家先朝遠(yuǎn)處看。長(zhǎng)城像不像一條在崇山峻嶺上伏臥的巨龍?它時(shí)隱時(shí)現(xiàn),正準(zhǔn)備騰空翱翔呢!長(zhǎng)城高大堅(jiān)固,它是由巨大的條石和城磚筑成的,是我國(guó)古代重要的軍事防御工程。
讓我們登上長(zhǎng)城看看吧。這里的城磚十分平坦,道路十分寬闊,要是在古代,五六匹馬可以并排行走。請(qǐng)大家再走近些看看,這里的城墻外沿還有兩米多高的成排的垛子,大家能猜到垛子上方形的口子有什么功用嗎?大家猜對(duì)了!這些方形的口子又稱(chēng)為t望口或射口,供古時(shí)戍守的將士們t望偵察和射擊防御。我們?cè)偕陨蕴ь^,可以看到城墻頂上每隔三百多米就有一座方形的城臺(tái),那是屯兵的堡壘。打仗的時(shí)候,城臺(tái)之間還可以相互呼應(yīng)呢?!?/p>
成功的導(dǎo)游詞不需要“眉毛胡子一把抓”,但要使內(nèi)容更豐富、語(yǔ)言更生動(dòng),快向我學(xué)習(xí)這幾個(gè)小妙招:首先,恰當(dāng)?shù)厥褂帽扔鳌M人、夸張、象征等手法,使靜止的景觀化為生動(dòng)鮮活的畫(huà)面,讓游客沉浸和陶醉其中;其次,運(yùn)用列數(shù)字的方法描述景觀的特點(diǎn),讓游客真正游有所得、有所收獲;再次,可以不失時(shí)機(jī)地穿插趣味盎然的神話(huà)傳說(shuō)、民間故事、詩(shī)文典故,引發(fā)游客的好奇心理,給他們留下深刻的印象。
“八達(dá)嶺長(zhǎng)城的墻體平均高7.8米,墻底寬6.5米至7.5米,頂寬4.5米。往下看是由兩個(gè)門(mén)洞和U字形墻組成的甕城。由于長(zhǎng)城是一個(gè)完整的軍事防御體系,因此它不僅有甕城和城墻,還有傳報(bào)軍情的烽火臺(tái)。
大家知道嗎?長(zhǎng)城是有感情的呢。關(guān)于長(zhǎng)城有一個(gè)傳說(shuō),相傳秦始皇時(shí)勞役繁重,青年男女范杞梁、孟姜女新婚不到三天,新郎就被抓去修長(zhǎng)城了。孟姜女在家等了很久也不見(jiàn)丈夫歸來(lái),就萬(wàn)里尋夫來(lái)到長(zhǎng)城腳下。不料丈夫已經(jīng)變成一堆白骨,孟姜女悲慟不已,在此大哭了三天三夜,哭倒了長(zhǎng)城,自己也變成了一塊望夫石?!?/p>
當(dāng)我們旅游專(zhuān)列第一站的游覽接近尾聲時(shí),小導(dǎo)游們可千萬(wàn)別忘了有禮貌地向游客道別,順便也給今天的游覽行程做一個(gè)小結(jié)。
一下車(chē),就看到了一塊大石碑,上面寫(xiě)著“八達(dá)嶺長(zhǎng)城”五個(gè)亮晶晶的大字。再往前看,一條長(zhǎng)龍臥在那蜿蜒的山峰上,一眼望不到邊。早在車(chē)上,導(dǎo)游就介紹過(guò)了,八達(dá)嶺長(zhǎng)城史稱(chēng)天下九塞之一,是萬(wàn)里長(zhǎng)城的精華,在明長(zhǎng)城中獨(dú)具代表性。既然是九塞之一,當(dāng)然是十分陡峭。所以年老體弱的可以先坐滑車(chē)到第四個(gè)烽火臺(tái),再登三個(gè)烽火臺(tái)到山頂,如果要當(dāng)好漢的那就要從山腳第一個(gè)烽火臺(tái)一直往上登到第七個(gè)烽火臺(tái)到山頂。聽(tīng)了導(dǎo)游的介紹后,我就躍躍欲試,當(dāng)然我是要做好漢的了。
我剛站在八達(dá)嶺城的入城口,我的腿就不禁抖起來(lái),那看起來(lái)聳入云霄的烽火臺(tái)與筆挺的臺(tái)階著實(shí)讓我不寒而栗。我心里不禁有點(diǎn)后悔了,那么陡,怎么爬得上去啊!做滑車(chē)多省心啊!可是這世界上是沒(méi)有后悔藥的。既然已經(jīng)來(lái)到了長(zhǎng)城腳底下了,那就登上山頂征服長(zhǎng)城吧!也不枉我來(lái)此一趟了。我戰(zhàn)勝了心中的膽怯大步往上攀登。
剛開(kāi)始臺(tái)階雖有些陡,但還能爬得上去,可過(guò)來(lái)一會(huì)兒,就越來(lái)越陡了,只好借助于長(zhǎng)城兩端建好的欄桿,扶著那長(zhǎng)長(zhǎng)地欄桿一步一步往上爬,慢慢地我終于登上了第一個(gè)烽火臺(tái),腳就像罐了鉛一樣,很酸!我站在烽火臺(tái)上極目遠(yuǎn)眺心曠神怡,山下都是郁郁蔥蔥的樹(shù)林,風(fēng)迎面吹來(lái),把我一身汗水吹得無(wú)影無(wú)蹤。我的力氣又回來(lái)了,繼續(xù)吧!爬過(guò)一道道斜坡和高高的臺(tái)階,爬一會(huì)兒休息一會(huì)兒,不管認(rèn)識(shí)的,還是不認(rèn)識(shí)的,老的少的,經(jīng)過(guò)身邊的時(shí)候都不忘相互提醒喊聲“加油”。經(jīng)過(guò)漫長(zhǎng)的上下斜坡路和近乎垂直地臺(tái)階。我和媽媽都沒(méi)了力氣,那長(zhǎng)長(zhǎng)的臺(tái)階似乎得意地在對(duì)我說(shuō):“哈哈,沒(méi)力氣了吧,登不上去了吧,就別當(dāng)好漢了,回去吧!”我的心中似乎一下子又充滿(mǎn)了力量,用手甩去額頭的汗珠,手攀著那漫長(zhǎng)而又結(jié)實(shí)的欄桿,腳踏著堅(jiān)定的步伐,心中充滿(mǎn)了登上長(zhǎng)城的信念。
那天天氣非常好,一大早我們就坐車(chē)去八達(dá)嶺長(zhǎng)城了。大概過(guò)了一個(gè)小時(shí),透過(guò)車(chē)窗,我看見(jiàn)遠(yuǎn)處出現(xiàn)了連綿不斷的高山,山峰上隱隱約約出現(xiàn)了白色的城墻,城墻在紅彤彤的朝霞的映襯下,猶如一條歪歪扭扭的金絲帶,爸爸告訴我那就是聞名中外的長(zhǎng)城。旅游車(chē)離長(zhǎng)城越來(lái)越近,我的心也越來(lái)越激動(dòng),感覺(jué)時(shí)間過(guò)得真慢!幾分鐘后,我們的車(chē)就來(lái)到了離長(zhǎng)城腳下不遠(yuǎn)處的車(chē)站,我迫不及待地下了車(chē)。
首先映入我眼簾的是鐫刻在路邊巨石上的名言:不到長(zhǎng)城非好漢。我們?cè)诰奘芭恼樟粲?爸爸興奮地對(duì)我說(shuō):“我們今天一定要做回好漢!”買(mǎi)好門(mén)票,我們就進(jìn)入景區(qū)了。我站在長(zhǎng)城的入口處,向遠(yuǎn)方眺望,只見(jiàn)長(zhǎng)城蜿蜒曲折、連綿不斷,遠(yuǎn)處的游人似一個(gè)個(gè)小點(diǎn),緩緩地上下移動(dòng)。我們一邊登長(zhǎng)城,爸爸一邊向我介紹長(zhǎng)城的知識(shí)。爸爸告訴我,八達(dá)嶺長(zhǎng)城是1505年的明朝開(kāi)始興建的,主要是為了抵御外敵的入侵,城墻兩邊鋸齒形的叫垛口,上面有?望口,下面有射擊口,高高的像樓房似的建筑叫烽火臺(tái),當(dāng)士兵發(fā)現(xiàn)有敵人入侵時(shí),就點(diǎn)燃烽火臺(tái)上預(yù)先準(zhǔn)備好的柴火,遠(yuǎn)處的士兵看見(jiàn)烽火臺(tái)上冒出的黑煙,便知道有敵情,會(huì)迅速趕來(lái)增援。聽(tīng)了爸爸的介紹,我想:我國(guó)古代的人民真聰明啊!
不知不覺(jué)中,我們就登上了一個(gè)烽火臺(tái),我向北面望去,只見(jiàn)城墻腳下山石起伏,我的眼前仿佛浮現(xiàn)了當(dāng)年戰(zhàn)爭(zhēng)的殘酷場(chǎng)面:千軍萬(wàn)馬滾滾而來(lái),城墻上戰(zhàn)鼓喧天,入侵的敵人有的手提大刀,有的手持長(zhǎng)槍,還有的肩扛炸藥……長(zhǎng)城上的士兵奮勇抵抗,到處是廝殺聲,到處是吶喊聲,到處是鮮血和尸體……我再看長(zhǎng)城的南面,一塊巨大的廣告牌展現(xiàn)在我的眼前,上面用中英文寫(xiě)著:同一個(gè)世界,同一個(gè)夢(mèng)想。我想這既是2008年北京奧運(yùn)會(huì)的宣傳語(yǔ),也是我們今天生活的真實(shí)寫(xiě)照,我們生活在和平年代,要更加珍惜來(lái)之不易的美好生活!
由于這天北風(fēng)很大,我們走得很慢,有時(shí)是走兩步退一步,所以我們不得不拉著扶手緩慢挪動(dòng)身體,其他的游客也是走走停停,顯得非常吃力,但是大家都沒(méi)有停下來(lái)的意思,因?yàn)槲覀兊墓餐繕?biāo)都是長(zhǎng)城的最高處--海拔888米的“好漢坡”。
長(zhǎng)城距今有2000多年的歷史,總長(zhǎng)50000多公里,是人類(lèi)歷史上占地面積最大的建筑。長(zhǎng)城非常雄偉。它西起嘉峪關(guān),東到三海關(guān),全長(zhǎng)有6700多公里,通稱(chēng)“萬(wàn)里長(zhǎng)城”。城墻平均高7、8米,頂寬7、8米,可以5馬并騎。萬(wàn)里長(zhǎng)城全部都用大條石和城磚砌成的。如果把大條石和城磚連起來(lái),就能繞地球一圈多。萬(wàn)里長(zhǎng)城不但雄偉,而且美觀。雄偉的巨龍穿行在叢林之中,城墻上面分布著成千上萬(wàn)座高大的烽火臺(tái),顯得雄奇險(xiǎn)峻充滿(mǎn)巨大的藝術(shù)魅力。萬(wàn)里長(zhǎng)城表現(xiàn)了勞動(dòng)人民的智慧和才干,是我國(guó)寶貴的歷史遺產(chǎn)。
名師點(diǎn)評(píng):小作者給我們介紹了萬(wàn)里長(zhǎng)城的有關(guān)知識(shí),通過(guò)閱讀小作者的文章,我們了解到了長(zhǎng)城的歷史、外貌及其在歷史上的地位。文章語(yǔ)言描寫(xiě)生動(dòng)形象,表達(dá)了小作者對(duì)長(zhǎng)城的贊美之情。“東到三海關(guān)”改為“東到山海關(guān)”。
五年級(jí):女孩載童年