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1、<p><b>  附 錄</b></p><p><b>  英文原文及中文翻譯</b></p><p><b>  (一)英文原文</b></p><p>  Physics of microwave technology in histochemistry</p>

2、<p>  L.P.KOK and M.E.BOON.</p><p>  Institute for Theoretical Physics, University of Groningen, P.O. Box 800, 9700 A V Groningen, The Netherlands Leiden Cytology and Pathology Laboratory, Leiden, The N

3、etherlands</p><p>  Summary Microwave technology has become important in preparatory techniques for microscopy in many different ways. This paper discusses various aspects of the physics of microwaves, It g

4、ives some theoretical background to understand the practical procedures. Some peculiarities in the optics of microwaves are pointed out, and the practical implications in particular of choosing the size and shape of samp

5、les and containers are discussed. Diffusion rates and chemical-reaction rates increase expone</p><p>  Introduction</p><p>  Sample preparation for histochemistry is an art, based on physical a

6、nd chemical processes. Microwaves can influence both processes. In this light, a multidisciplinary team in The Netherlands and some other European countries made an effort to look for benefits of microwave technology in

7、all fields of preparatory techniques. Fruits of this effort are described in detail elsewhere (Boon & Kok, 1988; Kok &Boon, 1990).</p><p>  Knowledge of both histochemistry and physics is needed to e

8、xploit the potentials of the application of microwave irradiation in histochemistry. Key factors in all preparatory techniques are diffusion (a physical process) and chemical-reaction rates. They are influenced by tempe

9、rature increase, and hence by microwave irradiation. The main effect of microwave irradiation in histochemistry is controllable temperature increase. If microwave irradiation is optimally applied, the resulting microscop

10、i</p><p>  Some history and the link with optics</p><p>  About one century ago, in 1888, Hertz discovered that electromagnetic radiation in the microwave and radio regions of the spectrum displ

11、ays the same basic behaviour as visible light. In fact, he showed that 66cm microwaves travel in straight lines, and can be reflected, refracted, and polarized in the same way light waves can. Thus microwaves exhibit dif

12、fraction and interference in the same way as visible light albeit on a different scale of length. The basic unit of length is the wavelength (λ)</p><p>  of this length scale. Large and small refer to size e

13、xpressed in λ. However, the wavelength of electromagnetic waves depends on the medium in which they propagate. Connected to this is the fact that the velocity of electromagnetic waves within most media is smaller than th

14、e velocity in vacuum or air. A wave has different wavelengths in different media. What remains the same is the frequency of the wave (expressed in Hz, named after Hertz).</p><p>  The unifying feature of all

15、 electromagnetic waves is that at all frequencies they have the same velocity in vacuum, c. Inside a medium the velocity v air smaller. In air the difference is small: a factor 1.000294. In fact, the factor by which it d

16、iffers depends on the frequency; the quoted figure is for visible light in air. The ratio n = c/v is the refractive index of the medium. For light in water n ≈1.33. Fluid water is a very special substance. At microwave f

17、requencies c/v = 9. This means th</p><p>  air. For example, for 2.45 GHz microwaves (used in kitchen and laboratory ovens), instead of 12.2cm, λwater is merely 12.2/9 ≈ 1.36 cm. Hence, in microwave applicat

18、ions in an aqueous environment an object is qualified as 'small' when it is smaller than a centimeter. 'Large' means its linear dimension at least exceeds λwater</p><p>  At low frequencies (

19、e.g., 50Hz mains, or 8MHz personal computer) electromagnetic-radiation aspects of the distribution of electromagnetic energy may be ignored. By contrast, at high frequency (e.g., visible light) these radiation aspects be

20、come dominant. Thinking in terms of lengths: if the characteristic electromagnetic wavelength is much larger than the typical sizes in our system (equipment), we may</p><p>  ignore radiation aspects. The fu

21、ndamental property of microwave technique is that it considers applications in which the characteristic wavelength is roughly the same size as the system (equipment, circuit . . . . ), or smaller, but yet not so small th

22、at we can merely use optical-ray techniques.</p><p>  Nevertheless, the lessons from optics can be a useful guide in predicting the behaviour of systems involving media and microwaves. This will be in partic

23、ular the</p><p>  case when the characteristic wavelength .is smaller than the typical size of the objects involved. The next two sections focus on this optical limit. We shall first discuss the optics of mi

24、crowaves propagating without absorption effects, i.e., we shall first make the simplifying assumption that the penetration depth in media (other than the perfectly reflecting metals) is infinitely large.</p><p

25、>  Optics of microwaves; reflection and refraction</p><p>  Perfectly conducting metal surfaces act like perfect mirrors to microwaves. This is the basic principle for the confinement of microwaves inside

26、 the oven chamber of the microwave oven, and for the transport of microwaves inside hollow metal wave guides. At th e interface of two different dielectric media both reflection and refraction take place. Part of the inc

27、ident wave (incident angle i) is reflected with angle of reflection r (with r = i), and another part is transmitted inside the medium. T</p><p>  the refraction law of Snell: nisin i = nt sin t. Here t is th

28、e angle of refraction, and ni and nt are the refractive indices of the first and the second medium, respectively. In the special case of incidence from vacuum, ni = 1 exactly, and the case of incidence from air, nair≈ 1.

29、 in both cases we effectively have sin i / sin t = n, where n is the relative refractive index, n ≥ 1. There is a fundamental relationship between n and the relative permittivity: n = 時(shí). For water, is anomalously large&

30、lt;/p><p>  Because there is both reflection and refraction it is of interest to know which fraction Q of a propagating microwave actually enters the object, and which fraction (hence 1-Q) is reflected. The fra

31、ction depends on the polarization of the wave. For waves with the electric-field vector parallel to the interface this fraction is Q1。 In the orthogonal polarization state this fraction is denoted by Q2。 </p><

32、p>  What does Snell's law teach us in the case of transition from a medium like water to vacuum (or air)? For this transition from medium i (water) to air, one has 9sin iwater = sin t. Unless water is sufficiently

33、 close to zero this equation has no real solution. This means there is no refraction, and thus there is perfect (100%) reflection back into the water. In other words: once the wave is refracted into the convex water mass

34、, there is a great chance it remains caught inside.</p><p>  Focusing effects and absorption of microwave energy</p><p>  So far we have discussed the optics of a plane microwave hitting a flat

35、interface between two media. We now turn to curved boundary surfaces. Here again reflection and refraction occur. The curvature of the surface may be used to focus microwaves. For example, a parabolic metallic mirror wil

36、l concentrate microwaves incident parallel to the axis upon reflection in the focal point. Radio telescopes are examples of such mirrors. Similarly, microwave beams refracted at curved surfaces can show a foc</p>

37、<p>  In Figure 1 we show the results of the ensuing computations for various values of n: n=l, 1.2, 1.4, 4, 9, and∞, respectively. For n=l the material of the sphere is completely microwave transparent. The waves p

38、ass without being deflected. For larger valuesof n the deflection of rays becomes appreciable. For n =1.4 there is 'focusing' on the axis outside the sphere. For n > 2 the focal region has shifted inside the

39、sphere.</p><p>  With increasing n this effect becomes more pronounced. For n=9 (appropriate for microwaves in fluid water) this focusing effect causes the rays to pass through or very near a point located a

40、t a distance of one ninth of the radius right of the center of the sphere. These plots are universal in the sense that they hold for each size of sphere.</p><p>  Microwaves, refracted into a medium, in prac

41、tice can be absorbed. To what extent, depends on how large (the imaginary part of the relative permittivity) is. It is a constant of the material and tabulated in the literature. No absorption occurs for = 0: these mate

42、rials are microwave transparent. (Examples are air, Styrofoam, many types of plastic.)</p><p>  In many practical cases absorption does occur; the waves entering the medium are damped. How much is determined

43、 by the value of , or alternatively by , or the preparation depth d. The wave is damped by the factor exp(-x/d), and hence the intensity as exp(-2x/d), where x is the total distance covered inside the medium. Absorption

44、has, as a direct consequence, the effect of heating up. </p><p>  Note that the theory that ignores absorption effects gives results completely independent of the actual size of the object, viz. the size of

45、the object in Fig. 1. With</p><p>  absorption, however, it makes a lot of difference whether d is much larger than the bali radius, or much smaller. In the former case all waves still reach the focal region

46、 with a considerable intensity, and the concentration effect in the central ball region illustrated in the figure is operating very effectively. When d is much smaller than the radius the microwaves will be extinguished

47、completely in the outer region of the ball. Then heating occurs only in the outer shell, before the focusing </p><p>  Experiments and numerical computations for loads with a high water content have been car

48、ried out by several authors. Kritikos & Schwan (1975) report calculations of diameter and frequency ranges where the maximum heating takes place inside a sphere. At 2.45 GHz a heating concentration in the central reg

49、ion of the ball is obtained for radii between 9mm and 5.5 cm. The focusing effect is a quasi-optical one for radii up to 2 cm, when maximum heating occurs in the centre. For radii over 2cm, the ma</p><p>  T

50、he distribution of heat generation by microwaves depends on the frequency of the microwaves, and on shape and radius, and dielectric properties of the load. The conditions for occurrence of 'focalized regions', w

51、here maximum heating occurs inside the sphere, are fulfilled for radii and dielectric properties in the range common for kitchen and laboratory items at 2.45 GHz. For large radii within this interval, quasi-optical mecha

52、nisms dominate. For smaller radii, such quasi-optical thinking seem</p><p>  Figure1 holds for cylinders, too. Here, the focusing effects will be less pronounced than for spherical bodies. (After all, a sphe

53、re has curvature in two directions, a cylinder only in one.) This is confirmed by experiment and computations.</p><p>  Fig. 1. Plane wave coming from the teft hits bali of dielectficum with a refractive ind

54、ex n = 1, 1.2, 1.4, 4, 9, and ∞. Respectively, individual rays, and the way they are refracted are shown. Not shown are the reflected waves. The value of n is indicated in the figure.</p><p><b> ?。ǘ┲形?/p>

55、翻譯</b></p><p>  組織化學(xué)中的物理微波技術(shù)</p><p>  L.P.KOK and M.E.BOON.</p><p>  理論物理學(xué)院,荷蘭格羅寧根大學(xué),Leiden細(xì)胞學(xué)和病理學(xué)實(shí)驗(yàn)室</p><p>  摘要:微波技術(shù)已成為重要的籌備顯微鏡技術(shù)在許多不同的方式。本文討論各方面的物理微波,它給出了一些了解實(shí)

56、際程序的理論背景。指出了一些特殊的光學(xué)微波,而在實(shí)際影響,特別討論了選擇樣品和容器的大小和形狀的情況。擴(kuò)散率和化學(xué)反應(yīng)速率與溫度呈指數(shù)增加,因此,在大多數(shù)組織化學(xué)的程序中,精確的溫度控制是必不可少的。這種由局部加熱的系統(tǒng),以及溫度傳感器所控制的過程是十分復(fù)雜的,但它們可能由于微波輻射的原因而出現(xiàn)。</p><p><b>  介紹</b></p><p>  基于物理

57、和化學(xué)兩個(gè)過程的化學(xué)樣品制備是一門藝術(shù)。微波能影響這兩個(gè)進(jìn)程。在這種情況下,一個(gè)在荷蘭和其他一些歐洲國家多學(xué)科小組在各個(gè)籌備技術(shù)領(lǐng)域做出努力研究,致力于尋找微波技術(shù)的益處。這項(xiàng)工作的成果在其他地方做了詳細(xì)敘述。</p><p>  組織化學(xué)和物理的知識探索微波輻射在組織化學(xué)中的應(yīng)用潛力。關(guān)鍵因素是,所有籌備技術(shù)的擴(kuò)散(物理過程)和化學(xué)反應(yīng)速率。它們是受氣溫升高的影響,因此組織化學(xué)中微波輻射的主要任務(wù)是控制溫度升高

58、。如果微波輻射得到最佳應(yīng)用,由于良好的過程控制,產(chǎn)生的顯微圖像也是高清晰的。在本篇文章中做了一些相關(guān)物理概念的審定:反射和折射,吸收,駐波效應(yīng),熱點(diǎn),以及微波爐中的溫度控制和溫度測量。</p><p>  一些光學(xué)的歷史與聯(lián)系</p><p>  大約一個(gè)世紀(jì)前,也就是1888年,赫茲發(fā)現(xiàn),電磁輻射中的微波和無線電地區(qū)的頻譜與可見光具有相同的特性。他表明,事實(shí)上66cm微波沿直線傳播直線,

59、并且可以被反射,光波可以以同樣的方式折射和偏振。因此微波所顯示的衍射和干涉與可見光的方式是相同的,盡管它們的長度是不同的?;締挝坏拈L度為波長(λ)的輻射,所有物體的微波應(yīng)用必須衡量這個(gè)尺度。大和小是參照λ所表示的大小而定的,然而波長的電磁波取決于他們在介質(zhì)中的傳播。連接到這是一個(gè)事實(shí),即電磁波在大多數(shù)媒介的速度小于在真空或空氣中速度。在不同的媒介中波具有不同的波長。仍然保持不變的是波的頻率(用表示赫茲,命名為赫茲)。</p>

60、;<p>  所有電磁波的統(tǒng)一功能是,在真空中所有頻率具有相同的速度,即光速 C.在介質(zhì)中速度v較小。它與在空氣中的不同是速度?。阂粋€(gè)因素1.000294 。事實(shí)上,其中的因素,取決于不同的頻率;引用的數(shù)字是對空氣中的可見光。每組的比例的C / V的折射率介質(zhì)。光與水的介質(zhì)比例n≈1.33 。流體:水是一個(gè)非常特殊的物質(zhì)。微波頻率的C / ν = 9 。這意味著,折射是異常龐大,而且水中的波長遠(yuǎn)小于在空氣中的波長。例如,對

61、于2.45千兆赫的微波( 廣泛的應(yīng)用于廚房和實(shí)驗(yàn)室中的微波爐) ,λwater僅僅是12.2/9 ≈ 1.36 cm而不是12.2cm。因此,在水環(huán)境中微波應(yīng)用的對象是符合‘小'的條件的,它是小于1cm ?!?#39;是指其線性尺寸至少 超過λwater。</p><p>  在低頻率(例如, 50Hz水管,或8MHz個(gè)人電腦)的電磁輻射方面,電磁能量分布可能被忽略。相比之下,在高頻率(例如, 可見光)

62、輻射方面成為主導(dǎo)。按照長度來考慮:如果電磁波波長的特性要遠(yuǎn)遠(yuǎn)大于在我們的系統(tǒng)(設(shè)備)中的一般大小,我們可能會(huì)忽略輻射方面。微波技術(shù)基本屬性的應(yīng)用,認(rèn)為作為一個(gè)系統(tǒng)在該特征波長尺寸大致是相同(如設(shè)備,電路......) ,或更小,但還沒有如此之小,我們可以僅僅使用光學(xué)射線技術(shù)。</p><p>  然而,來自光學(xué)的經(jīng)驗(yàn)在涉及介質(zhì)和微波等系統(tǒng)時(shí)可以成為指導(dǎo)預(yù)測系統(tǒng)一個(gè)有用的準(zhǔn)則。這是在特征波長小于所涉及的典型物體的大

63、小的情況下的一個(gè)特例。在未來兩節(jié)集中討論這一光學(xué)限制。我們將首先討論了光學(xué)不吸收情況下的微波傳播,即我們應(yīng)首先做出了簡化假設(shè),即媒介中的穿透深度(完全反射金屬除外)是無窮大。</p><p>  微波光學(xué):反射和折射</p><p>  理想導(dǎo)體金屬表面像完美的鏡子,以微波為例。這是禁閉微波烤箱內(nèi)庭微波爐以及用于運(yùn)輸微波爐內(nèi)金屬空心波導(dǎo)的基本原則。在次接口兩種不同介質(zhì)的媒體都反射和折射進(jìn)行

64、。部分入射波(入射角i)反射會(huì)產(chǎn)生反射波(反射角r=i) ,另一部分是內(nèi)部的傳播媒介。從而傳播方向一般是改變。衡量反射程度的是斯奈爾定律:nisin i = nt sin t,這里i是入射角,t是折射角,ni和nt分別是第一介質(zhì)和第二介質(zhì)的折射率。 在特殊情況下,ni= 1,確切的說來自空氣的介質(zhì)折射率nair≈ 1 。在這兩種情況下,我們有效地sin i/ sin t = n ,其中 n是相對折射率,n≥ 1 。有一個(gè)基本的關(guān)系n和相

65、對介電常數(shù):n = 。對水來說水,是異常大的順序號81 ,因此,n ≈ 9 。由于sin i ≤ 1 ,在這種情況下我們會(huì)很容易發(fā)現(xiàn)折射角t是永遠(yuǎn)不會(huì)大于arcsin (1/9) ≈ 。在病理學(xué)實(shí)驗(yàn)室其他物質(zhì)也是常用的,也是相當(dāng)大,見KOK和BOON的文章( 1988年) 。因此微波在進(jìn)入這些材料,將或多或少沿媒介的垂直邊界繼續(xù)傳播。</p><p>  因?yàn)橛蟹瓷浜驼凵洌灾繯的哪部分小部分傳播微波實(shí)際上進(jìn)

66、入的對象,哪一部分(因此1 - Q )是反射是有意思的。這個(gè)分?jǐn)?shù)取決于微波的極化特性。對波來說,電場矢量并行接口這部分是Q1,正交偏振態(tài)這一部分指的是Q2。</p><p>  斯奈爾定律告訴我們,在從像水一樣的介質(zhì)入射到真空(或空氣)的傳輸情況下。在這種傳輸中,9sin iwater = sin t,除非iwater足夠接近零否則該方程沒有實(shí)根。這意味著沒有折射,從而有完善的( 100 % )反射回水中。換句話

67、說:一旦波折射到凸水中,這是全部陷入其中的一個(gè)很好的機(jī)會(huì)。</p><p><b>  化學(xué)中的微波物理</b></p><p>  聚焦效應(yīng)和微波能量吸收</p><p>  迄今為止,我們討論了光學(xué)平面微波觸及兩個(gè)平面媒體之間的相互關(guān)系。我們現(xiàn)在彎曲邊界表面。在這里反射和折射再次發(fā)生。曲率的表面可以用來聚焦微波。例如,拋金屬反射鏡將集中入射

68、微波沿平行軸應(yīng)反射在聚焦點(diǎn)。射電望遠(yuǎn)鏡也是與之類似的一個(gè)例子。同樣,微波光線折射在曲面可以顯示聚焦效應(yīng)。作為一個(gè)范例,讓我們考慮類似于空氣中水的一種球形的介質(zhì)。這對土豆,番茄,或雞蛋來說是一個(gè)極好的模式。同樣,在上一節(jié)中,我們沒有考慮介質(zhì)內(nèi)的微波吸收。</p><p>  圖1中,我們顯示的結(jié)果,隨后的計(jì)算各種價(jià)值觀的n :n= 1 ,1.2,1.4 ,4.9和∞。n= 1的材料,微波領(lǐng)域是完全透明的,波完全通過

69、沒有偏轉(zhuǎn)。對于n是一個(gè)較大的值時(shí),偏轉(zhuǎn)射線成為可以觀察到。n = 1.4時(shí)焦點(diǎn)位于外表面的軸線商。n=2聯(lián)絡(luò)中心區(qū)域轉(zhuǎn)移到范圍內(nèi)。隨著n此效應(yīng)變得更加明顯。對n=9(適合微波在流體水)本集中效應(yīng)導(dǎo)致射線穿過或非常接近點(diǎn)位于距離九分之一半徑權(quán)利的中心領(lǐng)域。從意義上說這些地塊如此的普遍,以至于它們在表面上都占據(jù)特定的領(lǐng)域。</p><p>  折射到介質(zhì)中的微波,實(shí)際上是能夠被吸收的。多大程度上被吸收,取決于虛部的相

70、對介電常數(shù)的大小。這是一個(gè)恒定的物質(zhì),在文獻(xiàn)中有統(tǒng)計(jì)。當(dāng) = 0沒有吸收發(fā)生,這些是微波透明材料。 (例如,空氣,泡沫塑料,許多類型的塑料。 )</p><p>  在許多實(shí)際發(fā)生吸收案例,在波進(jìn)入介質(zhì)中是會(huì)發(fā)生衰減的。衰減的多少是由的值或者是、深度 d決定的。exp(-x/d)決定了波的阻尼衰減,因此,衰減強(qiáng)度就是exp(-2x/d),其中x表示延伸到介質(zhì)中的距離。一個(gè)直接后果就是吸收導(dǎo)致溫度升高。</p

71、><p>  需要注意的是忽視吸收的影響的理論使結(jié)果完全獨(dú)立于物體的實(shí)際大小,即圖1所示的物體的大小。然而就吸收而言,它又有大量的差異,是否深度d是遠(yuǎn)遠(yuǎn)大于巴厘半徑,還是更小。在前一種情況下,所有波傳播到中心區(qū)域仍然具有相當(dāng)?shù)膹?qiáng)度,圖像中在球中心地區(qū)聚焦作用說明這是非常有效。當(dāng)d遠(yuǎn)小于半徑時(shí),微波在球的外部區(qū)域?qū)⑼耆АT诰劢裹c(diǎn)可能產(chǎn)生任何重大影響之前,加熱只發(fā)生在外殼。</p><p> 

72、 一些作者進(jìn)行了高水分含量負(fù)載的實(shí)驗(yàn)和數(shù)值計(jì)算。Kritikos & Schwan( 1975年)的報(bào)告計(jì)算的直徑和頻率范圍的最高暖氣發(fā)生在一個(gè)領(lǐng)域。在2.45 GHz的供暖系統(tǒng)中集中在中部地區(qū)的球獲得9mm到5cm之間的半徑。聚焦效應(yīng)是一個(gè)半徑高達(dá)2厘米準(zhǔn)光,最大加熱發(fā)生在該中心。當(dāng)半徑超過2厘米時(shí),最大供熱區(qū)域從中心向表面緩慢運(yùn)行。Ohlsson and Risman( 1978 )利用紅外熱像照射伴隨有國內(nèi)微波爐所使用的2

73、.45 GHz的微波產(chǎn)生。對于幻象的食物,肉和馬鈴薯等,他們分別使用,36-i,16,60 –i20,他們觀察實(shí)驗(yàn)得到核心半徑在1~1.8cm之間時(shí)熱效應(yīng)最為顯著。對于半徑2.5cm仍然有一個(gè)明顯的聚焦效應(yīng)。對于一個(gè)半徑近4cm,表面加熱更加明顯高于核心暖氣,這與普通滲透深入的概念是相統(tǒng)一的。</p><p>  分配所產(chǎn)生的熱量取決于微波頻率的微波,以及形狀和半徑,和介電性能的負(fù)載。發(fā)生聚焦地區(qū)即發(fā)生最大暖氣的

74、領(lǐng)域條件是應(yīng)用于廚房和實(shí)驗(yàn)室項(xiàng)目的2.45GHz微波的各種常見半徑和介電常數(shù)來實(shí)現(xiàn)的。對于在此區(qū)間的大型半徑,準(zhǔn)光學(xué)機(jī)制占主導(dǎo)地位。對于較小的半徑,例如準(zhǔn)光學(xué)思想似乎已經(jīng)沒有什么意義。然而,由于內(nèi)部共振,在這種情況下核心暖氣就可能發(fā)生,駐波效應(yīng)是入射波和反射波之間的干擾所造成的現(xiàn)象。</p><p>  圖1 若表示圓柱面,在這里,聚焦效應(yīng)不如球面結(jié)構(gòu)明顯。(畢竟一個(gè)球體已在兩個(gè)方向彎曲,而圓柱面只有一個(gè)。)這一

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