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1、南昌航空大學(xué)科技學(xué)院學(xué)士學(xué)位論文PAGE PAGE 15 畢業(yè)設(shè)計(jì)(外文資料(zlio)原文及其翻譯)題目(tm): 滾筒式拋丸(po wn)清理機(jī)的總體和結(jié)構(gòu)設(shè)計(jì) 系 別 航空工程系 專業(yè)名稱 機(jī)械設(shè)計(jì)制造及其自動(dòng)化班級學(xué)號(hào) 學(xué)生姓名 指導(dǎo)教師 二O一一 年 6 月 外文(wiwn)翻譯譯文用拋丸清理機(jī)對板材軋輥進(jìn)行(jnxng)拋丸處理V. I. Meleshko, A. P. Kachailov, V. G. Boikov,V. L. Mazur, T. P, Kobka, 和 I. I. Krivolapov目前(mqin),軋制品的質(zhì)量受到許多關(guān)注,特別是板料。這從相當(dāng)大的程度上取決
2、于軋輥表面處理。許多公司著手提高軋輥表面處理的質(zhì)量,為輾壓作準(zhǔn)備。這篇文章的作者來自Zaporozhstal公司,Magnetogorsk冶金聯(lián)合企業(yè)的人員,有色冶金研究所, Dnepropetrovsk和Magnetogorsk采礦和冶金學(xué)院,來研究這個(gè)現(xiàn)實(shí)的問題。微表面質(zhì)量,或粗糙施工的冷軋板,對金屬的機(jī)械性能和生產(chǎn)性能,也對來自于這塊板料部分的最終質(zhì)量有影響。薄鋼板最終微表面的形成是通過對已用金屬球粗加工過的表面進(jìn)行工作輾壓得到的。通常情況下,對不合標(biāo)準(zhǔn)表面的工作輾壓粗加工是由氣動(dòng)力學(xué)和電動(dòng)拋丸清理機(jī)完成。在使用中的經(jīng)驗(yàn)表明國家鋼鐵廠使用的氣動(dòng)機(jī)不能滿足輥板表面拋丸處理的高質(zhì)量要求。 1
3、969年,Dnepropetrovsk冶金研究所在Zaprozhstal廠1號(hào)冷的混亂的磨房研究了SM-2型拋丸清理機(jī),發(fā)現(xiàn)了一些它結(jié)構(gòu)上的缺點(diǎn)。為了提供符合伏爾加汽車廠表面粗糙度要求的板料(粗糙度為0.8-1.6u),用于拋丸機(jī)設(shè)計(jì)的基本要求是確定的。機(jī)器必須滿足:在操作時(shí)一個(gè)持續(xù)的噴丸尺寸,換句話說,有效去除已磨損彈丸的既定尺寸;平穩(wěn)操作時(shí),控制拋丸機(jī)收集的空氣氣壓的可能性;在機(jī)器沒有特別的設(shè)備時(shí),對不同直徑(400-500mm)的工作輥的處理;控制簡單,維修方便。 圖一SM-2拋丸機(jī)(如圖1)是由一個(gè)裝有輪子的固定的封閉室1,一個(gè)可移動(dòng)噴管2(2在壓縮空氣的行動(dòng)下,對軋輥表面發(fā)射彈丸),
4、一個(gè)蠕蟲輸送機(jī)3,有分隔的傳送機(jī)4,拋丸裝置5,和排氣系統(tǒng)6組成。該設(shè)備安裝在一個(gè)低于地面水平1905毫米(ho m)的特殊地基上。有小車的機(jī)器的長度是15,200拉姆 ,高度是4070毫米,寬度4600毫米。操作的輥的尺寸是直徑400-500毫米,長度2000-4000毫米。整臺(tái)設(shè)備的總重量是15噸。 研究表現(xiàn)(bioxin)了操作中一個(gè)(y )工作中混合磨料磨損的動(dòng)力和彈丸變化的原始情況。在拋丸時(shí),彈丸在一個(gè)更大的尺寸范圍內(nèi)變化,磨損,形成許多微粒。在這種情況下,零件的拋丸取決于所用彈丸的尺寸。特定大小的微粒污染會(huì)破壞拋丸過程,使輥表面以及最后板料上的表面粗糙度降低。為了解決這些問題,有必
5、要既定期地檢查彈丸構(gòu)成,在拋丸過程中做適當(dāng)調(diào)整(在實(shí)際中很難做到),又要在機(jī)器運(yùn)行過程中篩選彈丸以提供特定大小的微粒。 拋丸過程中的穩(wěn)定性也是由送入噴管的彈丸的數(shù)量所決定的。實(shí)驗(yàn)表明,在氣壓2.5 -4.0atm下,提供0.3-0.4kg/sec的彈丸到運(yùn)行的兩個(gè)噴管中可以使操作穩(wěn)定。給機(jī)器裝配一個(gè)篩選裝置是一個(gè)保持彈丸尺寸的有效方法。理論上的數(shù)據(jù)和Zaporozhstal公司在SM-1 和TsKb_P-1拋丸清理機(jī)的實(shí)際操作經(jīng)驗(yàn)都證實(shí)了這一點(diǎn)。彈丸通過拋丸裝置傳送到輥表面,機(jī)器的封閉室被分為兩個(gè)隔膜(gm)間,每間分為三格,并配備一個(gè)電子氣動(dòng)控制裝置。工作(gngzu)混合物從上格式(g s
6、hi)下降到較低的,然后收集。在操作機(jī)器時(shí),排氣口被關(guān)閉(打開)。彈丸要么在電子氣動(dòng)控制裝置關(guān)閉閥門后送入,要么在操作者關(guān)閉拋丸機(jī)以后送入。當(dāng)機(jī)器關(guān)閉時(shí),出氣孔下降,并且在它和膜片之間形成了一個(gè)圓空5毫米寬的圓孔。排氣口是一個(gè)大約有30度的錐體,彈丸慢慢通過這一缺口,但不完全,然后彈丸直徑減少到10毫米。裝載噴口由控制裝置輪流打開。首次維修SM-2拋丸機(jī)時(shí),發(fā)現(xiàn)由于零件的腐蝕,控制系統(tǒng)經(jīng)常不運(yùn)行。正常磨料(根據(jù)銘牌三百七十五千克),在交替通過每個(gè)噴管后必須停止拋丸,因?yàn)橹罅硪粋€(gè)通過彈丸的低射艙室是不夠的。在拋丸時(shí)由于控制裝置不運(yùn)轉(zhuǎn),它不能從較高的艙室下降到較低的。僅僅在操作者將拋丸設(shè)備從空氣
7、系統(tǒng)中分離后,下一部分的彈丸才能被送過來。在這種情況下,兩個(gè)掌管的通風(fēng)口都必須被打開,磨料要被送到較低的艙室。機(jī)器的連續(xù)工作使磨料通過沒有控制裝置的三至四個(gè)噴管,在磨料增加到標(biāo)準(zhǔn)要求650kg后,上述彈丸的運(yùn)輸才變?yōu)榭赡堋H欢?,解決這個(gè)問題的基本方案還是控制裝置的穩(wěn)定運(yùn)行??捎玫膹椡枋怯晒ぷ魇业氖占撌占?,然后落入蠕蟲傳送機(jī)的接受槽。平行于蠕蟲傳送機(jī)的板材處在一個(gè)更大的角度,而那些垂線正處于一個(gè)角度,傾向于收集朝它們射來的彈丸。因此,在對一個(gè)輥板進(jìn)行拋丸后有必要關(guān)閉機(jī)器將累積的彈丸推到螺旋傳送器上。為了消除這個(gè)缺點(diǎn),將螺旋傳送器加長到工作室長度的一半是可行的。此外,更小的板料已經(jīng)完全消除,平
8、行板被拉長以符合蠕蟲輸送機(jī)的長度。提供給拋丸設(shè)備收集室的壓縮空氣被油水分離裝置烘干。然而,這種干燥方法是不夠的。水蒸氣凝結(jié)在主線和拋丸設(shè)備內(nèi),結(jié)果彈丸在低艙室內(nèi)都粘到一起,形成了堅(jiān)實(shí)的一堆。這一堆彈丸阻塞在垂直管內(nèi),阻礙了磨料沿著垂直管到達(dá)收集室的過程,也打亂了拋丸過程中彈丸拋向空中的最佳比例。這對拋丸過程及軋輥表面質(zhì)量有不良影響。空氣中存在的水分導(dǎo)致機(jī)器的腐蝕,也導(dǎo)致機(jī)器氣動(dòng)設(shè)備的操作性能更差。因此,在設(shè)計(jì)拋丸清理機(jī)時(shí),有必要指定干燥空氣的設(shè)備。例如,外國企業(yè)使用特殊的干燥設(shè)備利用吸水物質(zhì),如硅膠和活性氧化鋁干燥壓縮空氣。圖二移動(dòng)噴管的機(jī)制存在一些缺陷。磨料射到軋輥(zhgn)表面是通過一個(gè)
9、安裝在肘形槍管(圖2)上的噴管完成的。槍管的一個(gè)缺點(diǎn)是對壓縮空氣的混合物和彈丸的節(jié)流作用,節(jié)流處橫向和縱向的管道也在。交匯處是一個(gè)直角,這導(dǎo)致了肘形槍的快速磨損,管道和噴管的交界區(qū)域增加。然而,隨著噴管直徑從10毫米增加到12毫米(允許的最大值),空氣的消耗從13增加到19立方米每小時(shí),改變了彈丸射向空中的比例。然而,這個(gè)比例必須保持穩(wěn)定。因?yàn)樵趻佂柽^程中很難糾正這個(gè)問題,因此有必要改善設(shè)計(jì),增加零件的抗磨損度。為了這個(gè)目的設(shè)計(jì)了一款新型(xnxng)噴槍,它的管道直徑增大了(圖2b),從管道過渡到管道和噴嘴的形狀也改變了。提出并經(jīng)過(jnggu)測試,新的噴嘴設(shè)計(jì)更為有效。五個(gè)月的操作后,改
10、良后肘槍和噴管沒有發(fā)現(xiàn)顯著(xinzh)的磨損跡象,而舊的肘槍一個(gè)月后就損壞了。噴槍通過傳送帶沿著輥移動(dòng)。在臺(tái)車重量和它沿著導(dǎo)軌運(yùn)動(dòng)導(dǎo)致的振蕩的作用下,傳送帶離開對準(zhǔn)線。從輥表面落下的彈丸在導(dǎo)軌上積累。結(jié)果,彈丸流對其表面的作用不是一個(gè)直角,而是掃過,導(dǎo)致表面質(zhì)量更差。安置小條在肘槍之下解決了這個(gè)問題,而且使輥表面質(zhì)量變得更令人滿意。運(yùn)行初期,SM-2拋丸機(jī)的壓縮空氣是從主要線路間得到的,其間有6atm的壓力。根據(jù)在拋丸單位的收集室前安置的測壓器讀數(shù),其間的氣壓不超過4.0atm 。在這個(gè)氣壓下,即使用尺寸最合適的彈丸,輥的粗糙度也在上限(粗糙度為2.7u)。因此,有必要降低空氣的工作壓力???/p>
11、氣閥是用來控制壓力的,但它對空氣壓力的變化非常敏感,而且拋丸機(jī)的操作也不穩(wěn)定。因此,減壓閥被放置在油水分離器和拋丸設(shè)備間。這使我們能在精確度0.1atm下把在收集室的氣壓從4.0控制到2.0atm ??諝忾y的運(yùn)用使拋丸裝置能夠穩(wěn)定的運(yùn)行。為了把輥加工到不同直徑,有必要每次都改變拋丸槍的位置,而SM-2拋丸機(jī)的設(shè)計(jì)沒有提供這個(gè)功能。例如,現(xiàn)在要把直徑為400毫米的輥加工到500毫米,必須關(guān)閉拋丸機(jī)做調(diào)整。在設(shè)計(jì)新拋丸機(jī)時(shí),應(yīng)該考慮改變槍的高度的可能。為了觀察拋丸過程,燈火通明的工作艙長壁上開了一個(gè)特別的觀察窗。然而,觀察輥表面的拋丸過程是很困難的。因此,三個(gè)額外的500瓦燈泡在百葉窗的保護(hù)下,安
12、裝在工作艙的天花板上。圖三機(jī)器(圖3)的控制是通過控制面板2,在空中路線的閥5,用來控制輥的轉(zhuǎn)速和噴管移動(dòng)的變阻器,可以起動(dòng)排氣風(fēng)扇(fngshn)機(jī)、在機(jī)器后的起動(dòng)按鈕來完成的。SM-2拋丸裝置這樣的布置控制起來不方便,控制速度的變阻器沒有精確的范圍,這使決定正確的速度變的困難。事實(shí)上,為確定每個(gè)控制手柄的新位置,有必要決定速度。這些缺點(diǎn)在設(shè)計(jì)新機(jī)器的時(shí)候必須(bx)消除。排氣線的水平部分累積的金屬垃圾的清除也有必要改善。排氣線難以達(dá)到地面水平4米以上(yshng)的位置。為了給拋丸機(jī)的獨(dú)立單元提供更多方便和簡化它的維護(hù),鋼鐵冶金研究所開發(fā)并交給Zaporozhstal廠的建議已部分投入在現(xiàn)
13、有的機(jī)器使用,而且將研究設(shè)計(jì)類似的新機(jī)型。SM-2氣動(dòng)拋丸機(jī)的改進(jìn)使得控制和維持指定順序拋丸冷軋工作輥和表面通過板料站更加可能。因此,Zaporozhstal廠正大量生產(chǎn)被冷軋的建設(shè)板料,這些板料以符合有色冶金技術(shù)規(guī)格1-683-69 和 1-686-69的表面粗糙度生產(chǎn)。外文(wiwn)翻譯原文SHOT BLASTING MACHINES FOR THE BLASTING OF SHEET MILL ROLLSV. I. Meleshko, A. P. Kachailov, V. G. Boikov,V. L. Mazur, T. P, Kobka and I. I. KrivolapovA
14、t the present time much attention is being devoted to increasing the quality of rolled products, partieularly sheet. To a significant degree this depends upon the preparation of the roll surface. Many plants are engaged in improving the quality of working the roll surface in preparing them for rolli
15、ng.This article was written by personnel from Zaporozhstal Plant, Magnetogorsk Metallurgical Combine, the Institute for Ferrous Metallurgy, Dnepropetrovsk, and Magnetogorsk Mining and Metallurgical Institute on this very real problem.The surface microrelief, or roughness, of cold rolled construction
16、al sheet has an influence on the mechanical and production properties of metal, and also on the finish quality of parts made from this sheet. The final surface microrelief of thin sheet steel is formed in a skin pass on work roils which have been given a rough finish with metal shot.Normally the rou
17、gh surface finish on the work rolls of skin pass stands is produced in pneumatic and rotor shot blasting machines. Experience in their use has shownthat the pneumatic machines used in the countrys steel plants do not fill the need for high quality blasting of roll surfaces.In 1969 the Institute for
18、Ferrous Metallurgy, Dnepropetrovsk, did work on the SM-2 shot blasting machine in No. 1 Cold Roiling Mill of Zaprozhstal Plant, which revealed a number of shortcomings in its construction.To provide sheet with the surface roughness required by the specifications of Volga Automobile Plant (R a =0.8-1
19、.6 g),the basic requirements for the design of shot blasting machines were determined, The machine must provide:1. a constant shot size during operation, in other words, effective removal of shot of the specified size fromworn shot;2. the possibility of controlling air pressure in the collector of t
20、he shot blast machine during stable operations;3. the handling of work rolls of different diameters (400-500 mm) without special equipment on the machine;4. simplicity in control and convenience in maintenance.Fig.1The SM-2 machine (Fig. 1) consists of a stationary closed chamber ! with a trolley on
21、 wheels aad movab!enozzles 2 which under the action of compressed air discharge shot on to the roll surface, a worm conveyor 8, an elevator with a separator 4, the shot blast equipment 5, and an exhaust system 6. The equipment is mounted on a special foundation 1905 mm below the floor level The leng
22、th of the machine withthe trolley out is 15fl00 ram, the height 4070 ram, and the width 4600 mr The dimensions of the rolls handled are 400-500 mm in diameter and 2000-4000 mm in length. The total weight of the equipment is 15 tons.As research has shown, the dynamics of the wear of a working mixture
23、 of abrasive and the original condition of the shot changes during operation. During blasting, the shot takes on a wider size range and is worn down, forming many fine particles. The conditions under which the parts are blasted depend upon the size of the shot used. The contamination of the specifie
24、d size by fine particles disrupts the process, producing a poor quality surface on the rolls and consequently on the sheet. To eliminate these problems it is necessary to either regularly measure the composition of the shot and make appropriate changes in the blasting sequence, which is difficult to
25、 do in practice, or to screen the shot during operation of the machine to provide the specified particle size.Stability in the blasting process is also determined by the quantity of shot delivered to the nozzles. It was experimentally established that supplying 0.3-0.4 kg/sec of shot to the two nozz
26、les in operating with an air pressure of 2.5-4.0 atm provided stable operation. Equipping the machine with screening devices is an effective method for maintaining a constant shot size mix. This is confirmed both by data in the literature and by experience in the operation of SM-1 and TsKb_P-1 shot
27、blast machines at Zaporozhstal Plant.The shot is delivered to the surface of the roll by the shot blast equipment, the chamber of which is divided by two diaphragms with charging vents into three compartments and is equipped with an electropneumatic control device. The working mixture from the upper
28、 compartment of the chamber drops to the lower and then to the collector. During operation of the machine,the vents are closed (turned on). The shot is poured in either after turning off the valves by the electropneumatic control device, or after shutting down the machine by the operator. When it is
29、 turned off, the vent descends, and between it and the diaphragm a circular gap 5 mm wide is formed. The vent is a cone with a slope of about 30% The shot drops slowly through this gap but not completely, and therefore it increases to t0 ram. The loading vents are alternately turned on by the contro
30、l device. The first time the SM-2 machine was repaired, it was discovered that the control device frequently did not operate because of corrosion of the parts. With normal charging of abrasive (375 kg according to the nameplate), blasting must be stopped after each alternate pass of the nozzles, sin
31、ce after another pass the shot in the lower compartment is insufficient, and during blasting, With nonoperation of the control device, it does not drop from the upper compartment to the lower. Delivery of the nextportion of shot must be done only after the operator disconnects the shot blast equipme
32、nt from the air system. In this case both charging vents are opened, and the abrasive is fed to the lower compartment. Continuous operation of the machine for three or four passes of the nozzles with nonoperation of the control device and the delivery of shot described above became possible after in
33、creasing the standard charge to 650 kg. However, the basic solution of this problem is stable operation of the control device.The used shot is collected by the collecting bunker of the working chamber and drops into the receiving chute of the worm conveyor. The plates parallel to the worm conveyor a
34、re at a greater angle, and those perpendicular are at less of an angle, which tends to collect shot on them. Therefore, after blasting one roll it is necessary to shut the machine down to push the accumulated shot on to the screw conveyor. To eliminate this shortcoming, it is possible to lengthen th
35、e screw conveyor, which is half the length of the working chamber. In addition, the smaller plate is removed completely,and the parallel plates are elongated to correspond with the length of the worm conveyor.The compressed air supplied to the collector of the shot blast equipment is dried by an oil
36、 moisture separator. However, this method of drying is inadequate. Water vapor condenses in the main line and in the shot blast equipment, and as a result shot sticks together in the lower compartment and forms a solid mass. The solid mass clogs the vertical channels along which the abrasive is tran
37、sported to the collector and disrupts the optimum ratio of shot to air in the blast. This has a detrimental effect on the blasting process and the quality of the roll surface. The presence of moisture in the air causes corrosion of the equipment and causes operation of the pneumatic equipment of the
38、 machine to be poorer. Therefore, in designing shot blast equipment,it is necessary to specify equipment for drying the air. Foreign firms, for example, use special drying equipment utilizing water absorbing substances such as silica gel and activated alumina for drying compressed air.The mechanism
39、for moving the nozzle has a number of shortcomings. Application of the jet of abrasive material on to the roll is through a nozzle mounted in an elbow shaped gun (Fig. 2). A shortcoming of the gun is the throttling of the mixture of compressed air and shot where the vertical and horizontal channels
40、join. The junction is a right angle, which causes quick wearing away of the elbow. The cross sections of the channels and nozzle was increased. However, with an increase in the nozzle diameter from 10 to 12 mm (the allowable maximum) the consumptionof air increased from 13 to 19 mS/h, which changed
41、the ratio of shot to air in the blast. However, thisratio must be kept constant. Since during blasting it is difficult to make corrections, it was necessary o improve the design and increase the wear resistance of the parts.Fig.2For this purpose a new design of blast guns, in which the diameter of t
42、he channels was increased (Fig. 2 b) and the shape of the transition from the channel to the channel and nozzle was changed, was proposed and tested, The new nozzle design is much more effective. After five months of operation,noticeable signs of wear in the elbowand nozzle have not been found, whil
43、e the old design elbows wore out in a month.The blast guns are moved along the roll by a conveyor belt. Under the action of the weight of the troJ.ley and oscillations caused by its movement along the guides on which shot falling from the surface of the rolls accumulates, the belt gets out of alignm
44、ent. As a result, the impact of the stream of shot on the surface is not at a right angle, but glancing, which produces a poorer surface quality. Placing a strip under the gun eliminated this problem, and the roll surface quality became satisfactory.In the first period of operation the compressed ai
45、r tn the SM-2 machine was obtained from the shop main i,ine, which has a pressure of 6 atm. According to readings on a manometer placed before the collector of the shot btaat unit, the air pressure in it did not exceed 4.0 aim. With this pressure, even with the use of the finest shot (DChK-0.8), the
46、 roughness of the rolls is at the upper limit (R a = 2.7 #).Therefore, it was necessary to reduce the working pressure of the air. An air valve was used to control the pressure, but it was very sensitive to changes in air pressure, and operation of the shot blast machine was unstaSle. As a result, a
47、 reducing valve was placed between the oil moisture separator and the shot blast equipment. This made it possible to control the air pressure in the collector from 4.0 to 2.0 atm with an accuracy of 0.1 atrr. The use of this valve provides stable operation of the shot blast equipment.To blast rolls
48、of different diameters it is necessary each time to change the position of the blast gun, which is not provided for in the design of the SM-2 machine. For example, at the present time to blast a 400 mm diameter roll after a 500 mm roll the machine must be shut down for adjustment. In designing new s
49、hot blast machines the possibility of changing the height of the gun must be specified.To observe the blasting process, special observation windows were cut in the long wal! of the lighted working chamber. Nonetheless, observation of the surface of the roll being blasted was difficult. Therefore, three additional 500 W lights, protec
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