外文翻译
学院：嘉兴学院
专业：建筑环境与设备工程
班级：建环121
学号： 201251645123
姓名：陈晨
指导教师：阳季春
5
Radiation Transmission through Glazing: Absorbed Radiation
The transmission, reflection, and absorption of solar radiation by the various parts of a solar collector are important in determining collector performance. The transmittance, reflectance, and absorptance are functions of the incoming radiation, thickness, refractive index, and extinction coefficient of the material. Generally, the refractive index n and the extinction coefficient K of the cover material are functions of the wavelength of the radiation. However, in this chapter, all properties initially will be assumed to be independent of wavelength. This is an excellent assumption for glass, the most common solar collector cover material. Some cover materials have significant optical property variations with wavelength, and spectral dependence of properties is considered in Section 5.7. Incident solar radiation is unpolarized (or only slightly polarized). However, polarization considerations are important as radiation becomes partially polarized as it passes through collector covers.
The last sections of this chapter treat the absorption of solar radiation by collectors, collector-storage walls, and rooms on an hourly and on a monthly average basis.
Reviews of important considerations of transmission of solar radiation have been presented by Dietz (1954, 1963) and by Siegel and Howell (2002).
5.1 REFLECTION OF RADIATION
For smooth surfaces Fresnel has derived expressions for the reflection of unpolarized radiation on passing from medium 1 with a refractive index 1n to medium 2 with refractive index 2n :
2212
21sin ()
sin ()
r θθθθ⊥-=+ (5.1.1)
2212
21tan ()
tan ()r θθθθ-=+P (5.1.2） 2
r i r r I r I ⊥+=
=
P
(5.1.3)
where θ1 and θ2 are the angles of incidence and refraction, as shown in Figure 5.1.1. Equation 5.1.1 represents the perpendicular component of unpolarized radiation r ⊥, and Equation 5.1.2 represents the parallel component of unpolarized radiation r P . (Parallel and perpendicular refer to the plane defined by the incident beam and the surface normal.) Equation 5.1.3 then gives the reflection of unpolarized radiation as the average of the two components. The angles θ1 and θ2 are related to the indices of refraction by Snell’s law,
Figure 5.1.1 Angles of incidence and refraction in media with
refractive indices n 1 and n 2.
1122sin sin n n θθ= (5.1.4)
Thus if the angle of incidence and refractive indices are known, Equations 5.1.1 through 5.1.4 are sufficient to calculate the reflectance of the single interface
For radiation at normal incidence both θ1 and θ2 are zero, and Equations 5.1.3 and 5.1.4 can be combined to yield
2
1212(0)r i I n n r I n n ??-== ?
+??
（5.1.5）
If one medium is air (i.e., a refractive index of nearly unity), Equation 5.1.5 becomes
2
1(0)1n r n -??= ?
+??
(5.1.6)
Example 5.1.1
Calculate the reflectance of one surface of glass at normal incidence and at 60?. The average index of
refraction of glass for the solar spectrum is 1.526.
Solution
At normal incidence, Equation 5.1.6 can be used:
2
0.526(0)0.04342.526r ??== ???
At an incidence angle of 60?, Equation 5.1.4 gives the refraction angle θ2 :
12sin 60sin 34.581.526θ-??
==
???
From Equation 5.1.3, the reflectance is
2222
1sin (25.42)tan (25.42)1
(60)(0.1850.001)0.0932sin (92.58)tan (94.58)2
r ??--=+=+=????
In solar applications, the transmission of radiation is through a slab or film of material so there are two interfaces per cover to cause reflection losses. At off-normal incidence, the radiation reflected at an interface is different for each component of polarization, so the transmitted and reflected radiation becomes partially polarized. Consequently, it is necessary to treat each component of polarization separately.
Neglecting absorption in the cover material shown in Figure 5.1.2 and considering for the moment only the perpendicular component of polarization of the incoming radiation, （1-r ⊥） of the incident
beam reaches the second interface. Of this, 21r ⊥-（）
passes through the interface and r ⊥（1-r ⊥）is reflected back to the first, and so on. Summing the transmitted terms, the transmittance for the perpendicular component of polarization is
22
22
(1)1(1)
11n
n r r r r
r r τ∞
⊥⊥
⊥⊥⊥
=⊥⊥
--=-==-+∑ (5.1.7) Exactly the same expansion results when the parallel component of polarization is considered. The components r ⊥and r P are not equal (except at normal incidence), and the transmittance of initially unpolarized radiation is the average transmittance of the two components,
11121(21)1(21)rN
r r N r N r τ⊥⊥?
?--=+ ? ?+-+-??
P P (5.1.8) where the subscript r is a reminder that only reflection losses have been considered. For a system of N covers all of the same materials, a similar analysis yields
11121(21)1(21)rN
r r N r N r τ⊥⊥?
?--=+ ? ?+-+-??
P P (5.1.9)
Figure 5.1.2 Transmission through one nonabsorbing cover.
Example 5.1.2
Calculate the transmittance of two covers of nonabsorbing glass at normal incidence and at 60°. Solution
At normal incidence, the reflectance of one interface from Example 5.1.1 is 0.0434. From Equation 5.1.9, with both polarization components equal, the transmittance is
10.0434
(0)0.8513(0.0434)
r τ-=
=+
Also from Example 5.1.1 but at a 60? incidence angle, the reflectances of one interface for each component of polarization are 0.185 and 0.001. From Equation 5.1.9, the transmittance is
110.18510.001(60)0.76213(0.185)13(0.001)r τ??
--=+=??++??
The solar transmittance of nonabsorbing glass, having an average refractive index of 1.526 in the solar spectrum, has been calculated for all incidence angles in the same manner illustrated in Examples 5.1.1 and 5.1.2. The results for from one to four glass covers are given in Figure 5.1.3. This figure is a recalculation of the results presented by Hottel and Woertz (1942).
The index of refraction of materials that have been considered for solar collector covers are given in Table 5.1.1. The values correspond to the solar spectrum and can be used to calculate the angular
dependence of reflection losses similar to Figure 5.1.3.
Figure 5.1.3 Transmittance of 1, 2, 3, and 4 nonabsorbing covers having an index of refraction of
1.526.
Table 5.1.1 Average Refractive Index n in Solar
Spectrum of Some Cover Materials
5.2ABSORPTION BY GLAZING
The absorption of radiation in a partially transparent medium is described by Bouguer’s law, which is based on the assumption that the absorbed radiation is proportional to the local intensity in the medium and the distance x the radiation has traveled in the medium:
d I I K d x =- (5.2.1)
where K is the proportionality constant, the extinction coefficient, which is assumed to be a constant in the solar spectrum. Integrating along the actual pathlength in the medium (i.e., from zero to L/cos θ2) yields
Cover Material
Average
n
Glass
1.526 Polymethyl methacrylate 1.49 Polyvinylfluoride
1.45 Polyfluorinated ethylene propylene 1.34 Polytetrafluoroethylene 1.37 Polycarbonate 1.60
2=exp cos a I KL I τθ??=
- ???
transmitted
incident (5.2.2)
where the subscript a is a reminder that only absorption losses have been considered. For glass, the value of K varies from approximately 4 m ?1 for ‘‘water white’’ glass (which appears white when viewed on the edge) to approximately 32 m ?1 for high iron oxide content (greenish cast of edge) glass.
5.3OPTICAL PROPERTIES OF COVER SYSTEMS
The transmittance, reflectance, and absorptance of a single cover, allowing for both reflection and absorption losses, can be determined either by ray-tracing techniques similar to that used to derive Equation 5.1.7 or by the net radiation method as described by Siegel and Howell (2002). For the perpendicular component of polarization, the transmittance τ⊥ , reflectance ρ⊥ , and absorptance α⊥ of the cover are
()2222(1)111()11a a
a a r r r r r r τττττ⊥⊥
⊥
⊥⊥⊥
⊥??
---==??
-+-????
（5.3.1） ()
()
()2
22
111a a a r r r r r τρτττ⊥⊥⊥⊥
⊥⊥⊥-=+=+- （5.3.2）
1(1)1a a r r αττ⊥⊥⊥??
-=-
?-?
? （5.3.3）
Similarresultsarefoundfortheparallelcomponentofpolarization.Forincidentunpolarized radiation, the optical properties are found by the average of the two components.
The equation for the transmittance of a collector cover can be simplified by noting that the last term in Equation 5.3.1 (and its equivalent for the parallel component of polarization) is nearly unity, since τa is seldom less than 0.9 and r is on the order of 0.1 for practical collector covers. With this simplification and with Equation 5.1.8, the transmittance of a single cover becomes
a r τττ? (5.3.4)
This is a satisfactory relationship for solar collectors with cover materials and angles of practical interest.
The absorptance of a solar collector cover can be approximated by letting the last term in Equation 5.3.3 be unity so that
1a ατ?- (5.3.5)
Although the neglected term in Equation 5.3.3 is larger than the neglected term in Equation 5.3.1, the absorptance is much smaller than the transmittances so that the overall accuracy of the two approximations is essentially the same.
The reflectance of a single cover is then found from ρ = 1 ? α ? τ, so that
(1)a r a ρττττ?-=- (5.3.6)
The advantage of Equations 5.3.4 through 5.3.6 over Equations 5.3.1 through 5.3.3 is that polarization is accounted for in the approximate equations through the single term τr rather than by the more complicated expressions for each individual optical property. Example 5.3.1 shows a solution for transmittance by the exact equations and also by the approximate equations.
Example 5.3.1
Calculate the transmittance, reflectance, and absorptance of a single glass cover 2.3mm thick at an angle of 60?. The extinction coefficient of the glass is 32 m ?1.
Solution
At an incidence angle of 60?, the extinction coefficient —optical pathlength product is
2320.0023
0.0894cos cos34.58
KL θ?==
where 34.58 is the refraction angle calculated in Example 5.1.1. The transmittance τa from Equation 5.2.2 is then
()exp 0.08940.915a τ=-=
Using the results of Example 5.1.1 and Equation 5.3.1, the transmittance is found by averaging the transmittances for the parallel and perpendicular components of polarization,
22
220.91510.18510.18510.00110.001210.1851(0.1850.915)10.0011(0.0010.915)0.5(0.625+0.912)0.768
τ??????----=+??
? ?+-?+-???????==
The reflectance is found using Equation 5.3.2 for each component of polarization and averaging:
[]
0.50.185(10.9150.625)0.001(10.9150.912)0.5(0.2910.002)0.147
ρ=+?++?=+=
In a similar manner, the absorptance is found using Equation 5.3.3:
10.91510.18510.001210.1850.91510.0010.9150.085(0.981 1.000)0.085
2
α---??
=
+ ?
-?-???=+= Alternate Solution
The approximate equations can also be used to find these properties. From Equations 5.3.4 and 5.1.8 the transmittance is
0.91510.18510.0010.771210.18510.001τ--??
=
+= ?++??
From Equation 5.3.5, the absorptance is 10.9150.085α=-= and the reflectance is then
10.7710.0850.144ρ=--=
Note that even though the incidence angle was large and poor-quality glass was used in this example so that the approximate equations tend to be less accurate, the approximate method and the exact method are essentially in agreement.
Although Equations 5.3.4 through 5.3.6 were derived for a single cover, they apply equally well to identical multiple covers. The quantity
r τ should be evaluated from Equation 5.1.9 and the quantity
a τfrom Equation 5.2.2 with L equal to the total cover system thickness.
Example 5.3.2
Calculate the solar transmittance at incidence angles of zero and 60? for two glass covers each 2.3mm thick. The extinction coefficient of the glass is 16.1 m ?1, and the refractive index is 1.526. Solution
For one sheet at normal incidence,
16.10.00230.0370KL =?=
The transmittance a τis given as
[](0)exp 2(0.0370)0.93a τ=-=
The transmittance accounting for reflection, from Example 5.1.2, is 0.85. The total transmittance is then found from Equation 5.3.4:
(0)(0)(0)0.85(0.93)0.79r a τττ===
From Example 5.1.1, when θ1 = 60?, θ2 = 34.57?, and
2(0.0370)(60)exp 0.91cos34.58a τ??
=-
= ???
and the total transmittance (with r τ= 0.76 from Example 5.1.2) becomes
(60)(60)(60)0.76(0.91)0.69r a τττ===
Figure 5.3.1 gives curves of transmittance as a function of angle of incidence for systems of one to four identical covers of three different kinds of glass. These curves were calculated from Equation 5.3.4 and have been checked by experiments (Hottel and Woertz, 1942).
In a multicover system, the ray-tracing technique used to develop Equation 5.1.7 can be used to derive the appropriate equations. Whillier (1953) has generalized the ray-tracing method to any number or type of covers, and modern radiation heat transfer calculation methods have also been applied to these complicated situations (e.g., Edwards, 1977; Siegel and Howell, 2002). If the covers are identical, the approximate method illustrated in Example 5.3.2 is recommended, although the following equations can also be used.
For a two-cover system with covers not necessarily identical the following equations are for transmittance and reflectance, where subscript 1 refers to the top cover and subscript 2 to the inner cover:
()
12121212112211τττττττρρρρ⊥⊥????????=+=+ ? ?--??
??????
P P (5.3.7)
()
2121221122τρττρτρρρρρττ⊥⊥???
?????=+=+++ ? ?????????
P P (5.3.8)
Figure 5.3.1 Transmittance (considering absorption and reflection) of one, two, three, and four covers for three types of glass.
The reflectance of a cover system depends upon which cover is on top. In these equations the subscripts ⊥and || apply to all terms in the corresponding parentheses.
Example 5.3.3
Calculate the optical properties of a two-cover solar collector at an angle of 60?. The outer cover is glass with K = 16.1 m?1 and thickness of 2.3mm. The inner cover is polyvinyl fluoride with refractive index equal to 1.45. The plastic film is thin enough so that absorption within the plastic can be neglected. Solution
The optical properties of the glass and plastic covers alone, as calculated from Equations 5.3.1 through
5.3.3, are
Glass: 0.953τ=P , 0.655τ⊥=
0.002ρ=P , 0.302ρ⊥= 0.044α=P , 0.044α⊥=
Plastic: 0.995τ=P , 0.726τ⊥=
0.005ρ=P , 0.274ρ⊥=
0.000α=P , 0.000α⊥=
Equations 5.3.4 through 5.3.6 could have been used with each component of polarization to simplify the calculation of the preceding properties.
The transmittance of the combination is found from Equation 5.3.7:
10.6550.7260.9530.995210.3020.27410.0020.005=0.50.518+0.948=0.733
τ????
=+ ?
-?-??? （）
The reflectance, with the glass first, is found from Equation 5.3.8:
()10.5180.2740.655
0.9480.0050.953
=0.302+0.002
2
0.726
0.995=0.50.430+0.007=0.219
ρ?????
?++ ?
??
The absorptance is then
=10.2190.7730.048α--=
Equations 5.3.7 and 5.3.8 can be used to calculate the transmittance of any number of covers by repeated application. If subscript 1 refers to the properties of a cover system and subscript 2 to the properties of an additional cover placed under the stack, then these equations yield the appropriate transmittance and reflectance of the new system. The reflectance ρ1 in Equation 5.3.7 is the reflectance of the original cover system from the bottom side. If any of the covers exhibit strong wavelength-dependent properties, integration over the wavelength spectrum is necessary (see Section 5.6).
5 透过玻璃的辐射传递：吸收辐射
集热器的性能对太阳能集热器各个部位传递、反射、吸收的太阳辐射起重要决定作用。透射率、反射率、吸收率与材料的辐射入射角，厚度，折射率，消光系数成函数关系。一般来说，覆盖材料的折射率n 和消光系数K 是辐射波长的函数。在这一章节中，所有的参数属性最初都将假设为独立的波长，对于玻璃这种最常见的太阳能集热器覆盖材料这是一个很好的假设。一些其他的有重要光学性质，波长变化和光谱依赖性的覆盖材料将在章节5.7中有详细介绍。太阳的入射辐射都是非偏振的（或略偏振），然而，对偏振的考虑是十分重要的，因为当光通过太阳能集热器时会发生部分偏振现象。
本章的最后部分对一小时的和月平均的集热器、集热蓄热墙、房间吸收的太阳辐射进行说明。 迪茨(1954、1963)、西格尔和豪厄尔(2002)提出了太阳能辐射传递的重要内容。
5.1反射辐射
菲涅尔推导出非偏振光从折射率为1n 的光滑介质1传递到折射率为2n 的光滑介质2中的反射率公式：
2212
21sin ()
sin ()r θθθθ⊥-=+ （5.1.1） 221221tan ()
tan ()r θθθθ-=
+P （5.1.2） 2
r i r r I r I ⊥+==
P
（5.1.3）
在图5.1.1中1θ 和2θ 分别为入射角和折射角。公式5.1.1表达了非偏振光辐射的垂直方向分量r ⊥ 。公式5.1.2表达了非偏振光辐射的水平方向分量r P （入射光束的垂直和水平分量由参考平面和法线来定义）。公式5.1.3阐述了非偏振光入射的两个组成部分的平均量。
图5.1.1 太阳光通过折射率为1n 和2n 不同介质的折射角和入射角。
斯涅尔定律阐述了折射系数与角1θ 和2θ的关系：
1122sin sin n n θθ= （5.1.4）
因此如果已知折射率和入射角通过公式5.1.1和5.1.4可以明确的计算出一个界面的反射率。 当光线垂直入射时，角1θ 和2θ的值都为零时，公式5.1.3和5.1.4可以整合成
2
1212(0)r i I n n r I n n ??
-== ?+??
（5.1.5）
如果只有一个介质就是空气（也就是说，折射率接近1.0）则公式5.1.5就变成了
2
1(0)1n r n -??= ?+??
（5.1.6）
例题5.1.1
分别计算垂直入射和入射角为60°时，直射辐射在玻璃表面的反射率。已知玻璃的平均折射率为1.526 。
解答：当垂直入射时，用公式5.1.6得：
2
0.526(0)0.04342.526r ??== ???
当入射角为60°时，用公式5.1.4可以求出折射角2θ ：
12sin 60sin 34.581.526θ-??
==
???
根据公式5.1.3，得出反射率为：
22221sin (25.42)tan (25.42)1
(60)(0.1850.001)0.0932sin (92.58)tan (94.58)2
r ??--=+=+=????
在太阳能应用中，辐射都是通过平板材料或者是薄膜材料传输的，所以当光通过这两个界面
时都会造成反射损失。当入射光偏离法线时，界面的反射辐射与偏振光的各个组分是不同的。因
此，投射辐射和反射辐射会出现部分偏振现象。所以，对每个偏振分量进行处理是有必要的。
忽略界面的覆盖材料的吸收，如图5.1.2所示，只考虑入射瞬间的偏振光的垂直分量。入射光
束的剩余部分（1-r ⊥）到达第二个界面。同理有2
1r ⊥-（）
透射到下一个界面，r ⊥（1-r ⊥）反射回到第一个界面。结合传播条件，得出透射率垂直偏振分量的表达式：
22
220
(1)1(1)
11n
n r r r r
r r τ∞
⊥⊥
⊥⊥⊥
=⊥⊥
--=-==
-+∑ （5.1.7） 同样的也适用与偏振光的平行分量。当垂直分量r ⊥ 和平行分量r P 不相等时（除去法线射入），初始的非偏振光辐射的值为两个分量的平均值，
111211r r r r r τ⊥⊥??--=+ ? ?++??
P P （5.1.8） 小标r 强调，只考虑了反射损失。当面盖由N 层相同性质玻璃组成，类似分析可以得到： 11121(21)1(21)rN r r N r N r τ⊥⊥?
?--=+ ? ?+-+-??
P P （5.1.9）
图
5.1.2 一层界面的透射率（不考虑
吸收）
例题5.1.2
分别计算垂直入射和入射角为60°时，通过两块玻璃表面的透射率。
解答：当垂直入射时，由例题5.1.1得反射比为0.0434。由于两个偏振分量相等，由公式5.1.9得透射率：
10.0434
(0)0.8513(0.0434)
r τ-=
=+
当入射角为60°时，同样由例题5.1.1得两个分量的反射比为0.185和0.001。由公式5.1.9得透射率：
110.18510.001(60)0.76213(0.185)13(0.001)r τ??
--=+=??++??
太阳光谱的平均折射率为1.526，根据例题5.1.1和5.1.2
用同样的方法可以计算出所有不同入
射角对应的穿过不吸收玻璃的透射率。根据表面覆盖的玻璃块数的不同所有数据都在图5.1.3中画出。这一结果由Hottel 和Woertz （1942）重新校核。
折射指数与太阳能集热器覆盖材料的介质有关，见表5.1.1.。该值对应的太阳光谱可以用来计算类似雨图5.1.3的反射损失。
图5.1.3 折射率为1.526，1,2,3,4层玻璃的透射率（不考虑吸收）
表5.1.1 不同覆盖材料的平均折射率
5.2 玻璃吸收
布格定律描述了半透明介质对辐射的吸收，这是基于假设所吸收的辐射量和与介质中局部辐射量和辐射经过介质的距离x 成正比：
dI IKdx =- （5.2.1）
覆盖材料 平均折射率 玻璃 1.526 聚甲基丙烯酸甲酯
1.49 聚氟乙烯 1.45 聚全氟乙丙烯 1.34 聚四氟乙烯 1.37 聚碳酸酯
1.60
K 称为消光系数，在太阳光谱内假设为常数，透明材料的厚度为 L ，沿着介质中的实际路径积分为（从0到
2
cos L
θ）得：
2=exp cos a I KL I τθ??
=- ???
投射
入射 （5.2.2）
下标a 强调单纯吸收作用引起的透射率。对玻璃来说，K 的值大约从41
m -的 “水白”玻璃（出现白色的边缘）到321
m -氧化铁含量高的（绿边）玻璃。
5.3面盖材料的光学特性
通过追踪光线法，类似于公式5.1.7的推导或者是由西格尔和豪厄尔(2002)所提出的净辐射方法来确定一个面盖考虑反射和吸收两种损失的透射率、反射率和吸收率。其垂直偏振分量τ⊥ 、
ρ⊥ 、α⊥ 分别为：
()2222(1)111()11a a
a a r r r r r r τττττ⊥⊥⊥
⊥⊥⊥
⊥??
---==??
-+-????
（5.3.1） ()
()
()2
22
111a a a r r r r r τρτττ⊥⊥⊥⊥
⊥⊥⊥-=+=+- （5.3.2）
1(1)1a a r r αττ⊥⊥⊥??
-=-
?-??
（5.3.3）
相应的平行偏振分量，形式上与垂直的完全一样。对入射的非偏振辐射，两个分量的平均值就为其光学特性。
面盖的a τ值很少小于0.9，界面反射率r 数量级为0.1，公式5.3.1的末项变成1（它是偏振光水平分量的等效），集热器的透射率方程可以简化。根据公式5.1.8可以得出一个盖面的透射率简化公式：
a r τττ? （5.3.4）
这是一个令人满意的关系，符合太阳能集热器和面盖材料的实际利益。
一个面盖的太阳能集热器的吸收率可以近似由公式5.3.3推出：
1a ατ?- （5.3.5）
尽管公式5.3.3省略项比公式5.3.1省略项来得大，由于吸收率数值上比透射率小许多，所以两个近似式的总精度基本相等。
根据1ρατ=-- 可以得到一个面盖的反射率的近似式：
(1)a r a ρττττ?-=- （5.3.6）
通过对公式5.3.4，5.3.6与公式5.3.1 ，5.3.3的比较可以发现，用精确公式时，涉及各个偏振分量，近似公式的有点在于，只要对r τ 一项作偏振计算。例题5.3.1表现了精确和近似两种不同的方法来求解透射率。
例题 5.3.1
已知玻璃消光系数K=321
m - ，厚度L=32mm ，入射角为60°时，用精确和近似的方法求一层面盖的透射率、反射率、吸收率。
精确解法:
入射角为60°时，消光系数――辐射经过介质的距离的积分，
2320.0023
0.0894cos cos34.58
KL θ?==
34.58°由例题5.1.1的计算得到，a τ 由公式5.2.2计算，
()exp 0.08940.915a τ=-=
由例题5.1.1和公式5.3.1可以得到投射率为垂直偏振分量和平行偏振分量的平均值，
22
220.91510.18510.18510.00110.001210.1851(0.1850.915)10.0011(0.0010.915)0.5(0.625+0.912)0.768
τ??????----=+??
? ?+-?+-???????==
根据公式5.3.2得反射率为垂直偏振分量和平行偏振分量的平均值，
[]
0.50.185(10.9150.625)0.001(10.9150.912)0.5(0.2910.002)0.147
ρ=+?++?=+=
用类似的方法，根据公式5.3.3计算吸收率，
10.91510.18510.001210.1850.91510.0010.9150.085(0.981 1.000)0.085
2
α---??
=
+ ?
-?-???=+= 近似解法：
近似解法也要用到这些数据，从公式5.3.4和5.1.8可得出透射率，
0.91510.18510.0010.771210.18510.001τ--??
=
+= ?++??
根据公式5.3.5，吸收率为，10.9150.085α=-= 同理反射率为，10.7710.0850.144ρ=--=
注意，如果入射角很大或者使用劣质玻璃，使用近似方法往往是不准确的，近似方法和精确方法在本质上是一致的。
尽管通过公式5.3.4和5.3.6推导了一层面盖的计算方法，它们同样适用于相同的多层面盖。变量r τ由公式5.1.9求得，变量a τ由公式5.2.2求得，注意把各层的厚度L 加起来。
例题5.3.2
分别计算入射角为0°和60°时入射到两层玻璃盖面的透射率，每层玻璃厚度为2.3mm 。已知玻璃的消光系数为16.11
m - ，,折射率为1.526 。 解答：
入射角为0°时，射入单层盖面：16.10.00230.0370KL =?= 求出透射率a τ ：[](0)exp 2(0.0370)0.93a τ=-=
从例题5.1.2得到只考虑反射损失的透射率是0.85。从5.3.4得到总的透射率，
(0)(0)(0)0.85(0.93)0.79r a τττ===
根据例题5.1.1，当160θ=?时，2=34.58θ? ，2(0.0370)(60)exp 0.91cos34.58a τ??
=-= ???
总的透射率为（根据例题5.1.2得0.76r τ=）
(60)(60)(60)0.76(0.91)0.69r a τττ===
图5.3.1为透射率与入射角的函数关系，系统有三种不同的玻璃面盖。这些曲线的计算公式5.3.4已经由(豪特尔和沃尔茨，1942)进过实验验证。
在多层面盖覆盖系统中，可以根据公式5.1.7来用追踪光线法推导相应的公式。威廉（1953）用广义追踪光线法适用于任意数量和类型的面盖。现代辐射传热计算方法也被应用于这些复杂的情况(爱德华兹，1977；西格尔和豪厄尔，2002)。如果面盖种类一致，推荐使用公式5.3.2，虽然也可以使用下面的公式。对一个有两层面盖的系统，如果两层面盖的材料不一样。下面的公式就是计算透射率和反射率的，下标1指的是上面盖，下标2指的是下面盖：
()
12121212112211τττττττρρρρ⊥⊥????????=+=+ ? ?--??
??????
P P （5.3.7）
()
2121221122τρττρτρρρρρττ⊥⊥???
?????=+=+++ ? ?????????
P P （5.3.8）
图5.3.1三种玻璃1，2，3和4层面盖的透射率（考虑吸收和反射）
面盖系统的反射率决定于上层面盖的特性。下标⊥ 和P 适用于括号内的所有变量。 例题5.3.3
计算两层面盖系统的太阳能集热器当入射角为60°时光学特性。上层面盖的K=16.11
m - ，厚度为2.3mm .下层面盖为折射率等于1.45的聚氯乙烯。塑料薄膜足够薄，塑料的辐射吸收可以忽略。
Load and Ultimate Moment of Prestressed Concrete Action Under Overload-Cracking Load It has been shown that a variation in the external load acting on a prestressed beam results in a change in the location of the pressure line for beams in the elastic range.This is a fundamental principle of prestressed construction.In a normal prestressed beam,this shift in the location of the pressure line continues at a relatively uniform rate,as the external load is increased,to the point where cracks develop in the tension fiber.After the cracking load has been exceeded,the rate of movement in the pressure line decreases as additional load is applied,and a significant increase in the stress in the prestressing tendon and the resultant concrete force begins to take place.This change in the action of the internal moment continues until all movement of the pressure line ceases.The moment caused by loads that are applied thereafter is offset entirely by a corresponding and proportional change in the internal forces,just as in reinforced-concrete construction.This fact,that the load in the elastic range and the plastic range is carried by actions that are fundamentally different,is very significant and renders strength computations essential for all designs in order to ensure that adequate safety factors exist.This is true even though the stresses in the elastic range may conform to a recognized elastic design criterion. It should be noted that the load deflection curve is close to a straight line up to the cracking load and that the curve becomes progressively more curved as the load is increased above the cracking load.The curvature of the load-deflection curve for loads over the cracking load is due to the change in the basic internal resisting moment action that counteracts the applied loads,as described above,as well as to plastic strains that begin to take place in the steel and the concrete when stressed to high levels. In some structures it may be essential that the flexural members remain crack free even under significant overloads.This may be due to the structures’being exposed to exceptionally corrosive atmospheres during their useful life.In designing prestressed members to be used in special structures of this type,it may be necessary to compute the load that causes cracking of the tensile flange,in order to ensure that adequate safety against cracking is provided by the design.The computation of the moment that will cause cracking is also necessary to ensure compliance with some design criteria. Many tests have demonstrated that the load-deflection curves of prestressed beams are approximately linear up to and slightly in excess of the load that causes the first cracks in the tensile flange.(The linearity is a function of the rate at which the load is applied.)For this reason,normal elastic-design relationships can be used in computing the cracking load by simply determining the load that results in a net tensile stress in the tensile flange(prestress minus the effects of the applied loads)that is equal to the tensile strength of the concrete.It is customary to assume that the flexural tensile strength of the concrete is equal to the modulus of rupture of the
理工学院 毕业设计外文资料翻译 专业：计算机科学与技术 姓名：马艳丽 学号： 12L0752218 外文出处：The Design and Implementation of 3D Electronic Map of Campus Based on WEBGIS 附件： 1.外文资料翻译译文；2.外文原文。
附件1：外文资料翻译译文 基于WebGIS的校园三维电子地图的设计与实现 一．导言 如今，数字化和信息化是当今时代的主题。随着信息革命和计算机科学的发展，计算机技术已经渗透到科学的各个领域，并引起了许多革命性的变化，在这些科目，古代制图学也不例外。随着技术和文化的不断进步，地图变化的形式和内容也随之更新。在计算机图形学中，地理信息系统（GIS）不断应用到Web，制作和演示的传统方式经历了巨大的变化，由于先进的信息技术的发展，地图的应用已经大大延长。在这些情况下，绘图将面临广阔的发展前景。电子地图是随之应运而生的产品之一。随着计算机技术，计算机图形学理论，遥感技术，航空摄影测量技术和其他相关技术的飞速发展。用户需要的三维可视化，动态的交互性和展示自己的各种地理相关的数据处理和分析，如此多的关注应支付的研究三维地图。东北石油大学及其周边地区的基础上本文设计并建立三维电子地图。 二．系统设计 基于WebGIS的校园三维电子地图系统的具有普通地图的一般特性。通过按键盘上的箭头键（上，下，左，右），可以使地图向相应的方向移动。通过拖动鼠标，可以查看感兴趣的任何一个地方。使用鼠标滚轮，可以控制地图的大小，根据用户的需求来查看不同缩放级别的地图。在地图的左下角会显示当前鼠标的坐标。在一个div层，我们描绘了一个新建筑物的热点，这层可以根据不同的地图图层的显示，它也可以自动调整。通过点击热点，它可以显示热点的具体信息。也可以输入到查询的信息，根据自己的需要，并得到一些相关的信息。此外，通过点击鼠标，人们可以选择检查的三维地图和卫星地图。 主要功能包括： ?用户信息管理：检查用户名和密码，根据权限设置级别的认证，允许不同权限的用户通过互联网登录系统。 ?位置信息查询：系统可以为用户提供模糊查询和快速定位。
E---MARKETING (From:E--Marketing by Judy Strauss,Adel El--Ansary,Raymond Frost---3rd ed.1999 by Pearson Education pp .G4-G25.) As the growth of https://www.doczj.com/doc/e915741710.html, shows, some marketing principles never change.Markets always welcome an innovative new product, even in a crowded field of competitors ,as long as it provides customer value.Also,Google`s success shows that customers trust good brands and that well-crafted marketing mix strategies can be effective in helping newcomers enter crowded markets. Nevertheless, organizations are scrambling to determine how they can use information technology profitably and to understand what technology means for their business strategies. Marketers want to know which of their time-ested concepts will be enhanced by the Internet, databases,wireless mobile devices, and other technologies. The rapid growth of the Internet and subsequent bursting of the dot-com bubble has marketers wondering,"What next?" This article attempts to answer these questions through careful and systematic examination of successful e-mar-keting strategies in light of proven traditional marketing practices. （Sales Promotion;E--Marketing；Internet；Strategic Planning ） 1.What is E--Marketing E--Marketing is the application of a broad range of information technologies for: Transforming marketing strategies to create more customer value through more effective segmentation ,and positioning strategies；More efficiently planning and executing the conception, distribution promotion,and pricing of goods,services,and ideas;andCreating exchanges that satisfy individual consumer and organizational customers` objectives. This definition sounds a lot like the definition of traditional marketing. Another way to view it is that e-marketing is the result of information technology applied to traditional marketing. E-marketing affects traditional marketing in two ways. First,it increases efficiency in traditional marketing strategies.The transformation results in new business models that add customer value and/or increase company profitability.
外文出处： 《Exploiting Software How to Break Code》By Greg Hoglund, Gary McGraw Publisher : Addison Wesley Pub Date : February 17, 2004 ISBN : 0-201-78695-8 译文标题： JDBC接口技术 译文： JDBC是一种可用于执行SQL语句的JavaAPI（ApplicationProgrammingInterface应用程序设计接口）。它由一些Java语言编写的类和界面组成。JDBC为数据库应用开发人员、数据库前台工具开发人员提供了一种标准的应用程序设计接口，使开发人员可以用纯Java语言编写完整的数据库应用程序。 一、ODBC到JDBC的发展历程 说到JDBC，很容易让人联想到另一个十分熟悉的字眼“ODBC”。它们之间有没有联系呢？如果有，那么它们之间又是怎样的关系呢？ ODBC是OpenDatabaseConnectivity的英文简写。它是一种用来在相关或不相关的数据库管理系统（DBMS）中存取数据的，用C语言实现的，标准应用程序数据接口。通过ODBCAPI，应用程序可以存取保存在多种不同数据库管理系统（DBMS）中的数据，而不论每个DBMS使用了何种数据存储格式和编程接口。 1．ODBC的结构模型 ODBC的结构包括四个主要部分：应用程序接口、驱动器管理器、数据库驱动器和数据源。应用程序接口：屏蔽不同的ODBC数据库驱动器之间函数调用的差别，为用户提供统一的SQL编程接口。 驱动器管理器：为应用程序装载数据库驱动器。 数据库驱动器：实现ODBC的函数调用，提供对特定数据源的SQL请求。如果需要，数据库驱动器将修改应用程序的请求，使得请求符合相关的DBMS所支持的文法。 数据源：由用户想要存取的数据以及与它相关的操作系统、DBMS和用于访问DBMS的网络平台组成。 虽然ODBC驱动器管理器的主要目的是加载数据库驱动器，以便ODBC函数调用，但是数据库驱动器本身也执行ODBC函数调用，并与数据库相互配合。因此当应用系统发出调用与数据源进行连接时，数据库驱动器能管理通信协议。当建立起与数据源的连接时，数据库驱动器便能处理应用系统向DBMS发出的请求，对分析或发自数据源的设计进行必要的翻译，并将结果返回给应用系统。 2．JDBC的诞生 自从Java语言于1995年5月正式公布以来，Java风靡全球。出现大量的用java语言编写的程序，其中也包括数据库应用程序。由于没有一个Java语言的API，编程人员不得不在Java程序中加入C语言的ODBC函数调用。这就使很多Java的优秀特性无法充分发挥，比如平台无关性、面向对象特性等。随着越来越多的编程人员对Java语言的日益喜爱，越来越多的公司在Java程序开发上投入的精力日益增加，对java语言接口的访问数据库的API 的要求越来越强烈。也由于ODBC的有其不足之处，比如它并不容易使用，没有面向对象的特性等等，SUN公司决定开发一Java语言为接口的数据库应用程序开发接口。在JDK1．x 版本中，JDBC只是一个可选部件，到了JDK1．1公布时，SQL类包（也就是JDBCAPI）
华北电力大学科技学院 毕业设计（论文）附件 外文文献翻译 学号：121912020115姓名：彭钰钊 所在系别：动力工程系专业班级：测控技术与仪器12K1指导教师：李冰 原文标题：Infrared Remote Control System Abstract 2016 年 4 月 19 日
红外遥控系统 摘要 红外数据通信技术是目前在世界范围内被广泛使用的一种无线连接技术，被众多的硬件和软件平台所支持。红外收发器产品具有成本低，小型化，传输速率快，点对点安全传输，不受电磁干扰等特点，可以实现信息在不同产品之间快速、方便、安全地交换与传送，在短距离无线传输方面拥有十分明显的优势。红外遥控收发系统的设计在具有很高的实用价值，目前红外收发器产品在可携式产品中的应用潜力很大。全世界约有1亿5千万台设备采用红外技术，在电子产品和工业设备、医疗设备等领域广泛使用。绝大多数笔记本电脑和手机都配置红外收发器接口。随着红外数据传输技术更加成熟、成本下降，红外收发器在短距离通讯领域必将得到更广泛的应用。 本系统的设计目的是用红外线作为传输媒质来传输用户的操作信息并由接收电路解调出原始信号，主要用到编码芯片和解码芯片对信号进行调制与解调，其中编码芯片用的是台湾生产的PT2262，解码芯片是PT2272。主要工作原理是：利用编码键盘可以为PT2262提供的输入信息，PT2262对输入的信息进行编码并加载到38KHZ的载波上并调制红外发射二极管并辐射到空间，然后再由接收系统接收到发射的信号并解调出原始信息，由PT2272对原信号进行解码以驱动相应的电路完成用户的操作要求。 关键字：红外线；编码；解码；LM386；红外收发器。 1 绪论
Journal of Industrial Textiles https://www.doczj.com/doc/e915741710.html,/ Optimization of Parameters for the Production of Needlepunched Nonwoven Geotextiles Amit Rawal, Subhash Anand and Tahir Shah 2008 37: 341Journal of Industrial Textiles DOI: 10.1177/1528083707081594 The online version of this article can be found at: https://www.doczj.com/doc/e915741710.html,/content/37/4/341 Published by: https://www.doczj.com/doc/e915741710.html, can be found at:Journal of Industrial TextilesAdditional services and information for https://www.doczj.com/doc/e915741710.html,/cgi/alertsEmail Alerts: https://www.doczj.com/doc/e915741710.html,/subscriptionsSubscriptions: https://www.doczj.com/doc/e915741710.html,/journalsReprints.navReprints: https://www.doczj.com/doc/e915741710.html,/journalsPermissions.navPermissions: https://www.doczj.com/doc/e915741710.html,/content/37/4/341.refs.htmlCitations: - Mar 28, 2008Version of Record >>
外文翻译 专业机械设计制造及其自动化学生姓名刘链柱 班级机制111 学号1110101102 指导教师葛友华
外文资料名称： Design and performance evaluation of vacuum cleaners using cyclone technology 外文资料出处：Korean J. Chem. Eng., 23(6), (用外文写) 925-930 (2006) 附件： 1.外文资料翻译译文 2.外文原文
应用旋风技术真空吸尘器的设计和性能介绍 吉尔泰金，洪城铱昌，宰瑾李， 刘链柱译 摘要：旋风型分离器技术用于真空吸尘器 - 轴向进流旋风和切向进气道流旋风有效地收集粉尘和降低压力降已被实验研究。优化设计等因素作为集尘效率，压降，并切成尺寸被粒度对应于分级收集的50％的效率进行了研究。颗粒切成大小降低入口面积，体直径，减小涡取景器直径的旋风。切向入口的双流量气旋具有良好的性能考虑的350毫米汞柱的低压降和为1.5μm的质量中位直径在1米3的流量的截止尺寸。一使用切向入口的双流量旋风吸尘器示出了势是一种有效的方法，用于收集在家庭中产生的粉尘。 摘要及关键词：吸尘器; 粉尘; 旋风分离器 引言 我们这个时代的很大一部分都花在了房子，工作场所，或其他建筑，因此，室内空间应该是既舒适情绪和卫生。但室内空气中含有超过室外空气因气密性的二次污染物，毒物，食品气味。这是通过使用产生在建筑中的新材料和设备。真空吸尘器为代表的家电去除有害物质从地板到地毯所用的商用真空吸尘器房子由纸过滤，预过滤器和排气过滤器通过洁净的空气排放到大气中。虽然真空吸尘器是方便在使用中，吸入压力下降说唱空转成比例地清洗的时间，以及纸过滤器也应定期更换，由于压力下降，气味和细菌通过纸过滤器内的残留粉尘。 图1示出了大气气溶胶的粒度分布通常是双峰形，在粗颗粒（>2.0微米）模式为主要的外部来源，如风吹尘，海盐喷雾，火山，从工厂直接排放和车辆废气排放，以及那些在细颗粒模式包括燃烧或光化学反应。表1显示模式，典型的大气航空的直径和质量浓度溶胶被许多研究者测量。精细模式在0.18?0.36 在5.7到25微米尺寸范围微米尺寸范围。质量浓度为2?205微克，可直接在大气气溶胶和 3.85至36.3μg/m3柴油气溶胶。
毕业论文外文文献翻译 毕业设计（论文）题目关于企业内部环境绩效审计的研究翻译题目最高审计机关的环境审计活动 学院会计学院 专业会计学 姓名张军芳 班级09020615 学号09027927 指导教师何瑞雄
最高审计机关的环境审计活动 1最高审计机关越来越多的活跃在环境审计领域。特别是1993-1996年期间，工作组已检测到环境审计活动坚定的数量增长。首先，越来越多的最高审计机关已经活跃在这个领域。其次是积极的最高审计机关，甚至变得更加活跃：他们分配较大部分的审计资源给这类工作，同时出版更多环保审计报告。表1显示了平均数字。然而，这里是机构间差异较大。例如，环境报告的数量变化，每个审计机关从1到36份报告不等。 1996-1999年期间，结果是不那么容易诠释。第一，活跃在环境审计领域的最高审计机关数量并没有太大变化。“活性基团”的组成没有保持相同的：一些最高审计机关进入，而其他最高审计机关离开了团队。环境审计花费的时间量略有增加。二，但是，审计报告数量略有下降，1996年和1999年之间。这些数字可能反映了从量到质的转变。这个信号解释了在过去三年从规律性审计到绩效审计的转变（1994-1996年，20％的规律性审计和44％绩效审计;1997-1999：16％规律性审计和绩效审计54％）。在一般情况下，绩效审计需要更多的资源。我们必须认识到审计的范围可能急剧变化。在将来，再将来开发一些其他方式去测算人们工作量而不是计算通过花费的时间和发表的报告会是很有趣的。 在2000年，有62个响应了最高审计机关并向工作组提供了更详细的关于他们自1997年以来公布的工作信息。在1997-1999年，这62个最高审计机关公布的560个环境审计报告。当然，这些报告反映了一个庞大的身躯，可用于其他机构的经验。环境审计报告的参考书目可在网站上的最高审计机关国际组织的工作组看到。这里这个信息是用来给最高审计机关的审计工作的内容更多一些洞察。 自1997年以来，少数环境审计是规律性审计（560篇报告中有87篇，占16％）。大多数审计绩效审计（560篇报告中有304篇，占54％），或组合的规律性和绩效审计（560篇报告中有169篇，占30％）。如前文所述，绩效审计是一个广泛的概念。在实践中，绩效审计往往集中于环保计划的实施（560篇报告中有264篇，占47％），符合国家环保法律，法规的，由政府部门，部委和/或其他机构的任务给访问（560篇报告中有212篇，占38％）。此外，审计经常被列入政府的环境管理系统（560篇报告中有156篇，占28％）。下面的元素得到了关注审计报告：影响或影响现有的国家环境计划非环保项目对环境的影响;环境政策;由政府遵守国际义务和承诺的10％至20％。许多绩效审计包括以上提到的要素之一。 1本文译自：S. Van Leeuwen.(2004).’’Developments in Environmental Auditing by Supreme Audit Institutions’’ Environmental Management Vol. 33, No. 2, pp. 163–1721
毕业设计（论文） 外文翻译 题目西安市水源工程中的 水电站设计 专业水利水电工程 班级 学生 指导教师 2016年
研究钢弧形闸门的动态稳定性 牛志国 河海大学水利水电工程学院，中国南京，邮编210098 nzg_197901@https://www.doczj.com/doc/e915741710.html,，niuzhiguo@https://www.doczj.com/doc/e915741710.html, 李同春 河海大学水利水电工程学院，中国南京，邮编210098 ltchhu@https://www.doczj.com/doc/e915741710.html, 摘要 由于钢弧形闸门的结构特征和弹力，调查对参数共振的弧形闸门的臂一直是研究领域的热点话题弧形弧形闸门的动力稳定性。在这个论文中，简化空间框架作为分析模型，根据弹性体薄壁结构的扰动方程和梁单元模型和薄壁结构的梁单元模型，动态不稳定区域的弧形闸门可以通过有限元的方法，应用有限元的方法计算动态不稳定性的主要区域的弧形弧形闸门工作。此外，结合物理和数值模型，对识别新方法的参数共振钢弧形闸门提出了调查，本文不仅是重要的改进弧形闸门的参数振动的计算方法，但也为进一步研究弧形弧形闸门结构的动态稳定性打下了坚实的基础。 简介 低举升力，没有门槽，好流型，和操作方便等优点，使钢弧形闸门已经广泛应用于水工建筑物。弧形闸门的结构特点是液压完全作用于弧形闸门，通过门叶和主大梁，所以弧形闸门臂是主要的组件确保弧形闸门安全操作。如果周期性轴向载荷作用于手臂，手臂的不稳定是在一定条件下可能发生。调查指出:在弧形闸门的20次事故中，除了极特殊的破坏情况下，弧形闸门的破坏的原因是弧形闸门臂的不稳定;此外，明显的动态作用下发生破坏。例如:张山闸，位于中国的江苏省，包括36个弧形闸门。当一个弧形闸门打开放水时，门被破坏了，而其他弧形闸门则关闭，受到静态静水压力仍然是一样的，很明显，一个动态的加载是造成的弧形闸门破坏一个主要因素。因此弧形闸门臂的动态不稳定是造成弧形闸门(特别是低水头的弧形闸门)破坏的主要原是毫无疑问。
外文翻译 原文 Marketing Material Source：Marketing Management Author：Philip Kotler Marketing Channels To reach a target market, the marketer uses three kinds of marketing channels. Communication channels deliver messages to and receive messages from target buyers. They include newspapers, magazines, radio, television, mail, telephone, billboards, posters, fliers, CDs, audiotapes, and the Internet. Beyond these, communications are conveyed by facial expressions and clothing, the look of retail stores, and many other media. Marketers are increasingly adding dialogue channels (e-mail and toll-free numbers) to counterbalance the more normal monologue channels (such as ads). The marketer uses distribution channels to display or deliver the physical product or service to the buyer or user. There are physical distribution channels and service distribution channels, which include warehouses, transportation vehicles, and various trade channels such as distributors, wholesalers, and retailers. The marketer also uses selling channels to effect transactions with potential buyers. Selling channels include not only the distributors and retailers but also the banks and insurance companies that facilitate transactions. Marketers clearly face a design problem in choosing the best mix of communication, distribution, and selling channels for their offerings. Supply Chain Whereas marketing channels connect the marketer to the target buyers, the supply chain describes a longer channel stretching from raw materials to components to final products that are carried to final buyers. For example, the supply chain for women’s purses starts with hides, tanning operations, cutting operations, manufacturing, and the marketing channels that bring products to customers. This supply chain represents a value delivery system. Each company captures only a certain percentage of the total value generated by the supply chain. When a company acquires competitors or moves upstream or downstream, its aim is
华南理工大学广州学院 本科毕业设计（论文）外文翻译 外文原文名Marketing Strategy Adjustment and Marketing Innovation in the Experience Economy Era 中文译名体验经济时代的营销战略调整与营销创新 学院管理学院 专业班级2013级工商管理1班 学生姓名潘嘉谊 学生学号201330090184 指导教师罗玲苑讲师李巍巍 填写日期2017年5月19日
外文原文版出处：.Marketing Strategy Adjustment and Marketing Innovation in the Experience Economy Era[J]. Contemporary Logistics,2012 (06) :230-267 译文成绩：指导教师（导师组长）签名： 译文： 体验经济时代的营销战略调整与营销创新 吴青学 摘要：从商品货物经济，到服务经济的的转移演化经历过程，经历了农业经济、工业经济，服务经济和体验经济。在服务经济时期，企业只是打包经验与传统的产品一起销售，而在促进经验经济的时期，企业要把最好产品为未来的潜在用户设计，让消费者心甘情愿支付购买产品。 关键词：体验经济；市场营销战略；营销创新 1 介绍 随着科学技术和信息行业的发展，人们的需要和欲望连同消费者支出模式开始发生转变，相应地对企业生产环境产生了一系列影响。经济社会发展由传统时期进入体验经济时期。从一个经济产品的转变，进而到经济体系经济模式的转变。由缓慢转变为激进经济模式。因此导致社会发展从一个经济时期到另一个经济时期，经济模式和经济体系的转变将不可避免地影响到交换关系的转化。这是关注体验的结果，是由人类社会的发展的规律所决定的生产水平的产物。一旦交流关系发生变化、营销模式必须做出相应的变化。 2 企业营销策略的选择方向 在体验经济时代，企业不仅要理性思考高瞻远瞩，从客户的角度实施营销活动，更要重视与沟通客户，发现在他们内心的期望。我们自己的产品和服务代表企业的形象，产品要指向指定的客户体验。在当今时代，体验营销已成为营销活动最强大的秘密武器因此，这是非常重要的。而传统的营销策略，包括调整经验营销都已经不适应当前发展需求，迟早要被时代所淘汰。 2.1 建立营销思想的观念要求提高客户体验 根据马斯洛需求层次理论，人的需要分为五个层次，分别是：生理的需要、安全的需要、归属于爱的需要、尊重的需要和自我实现的需要。随着经济的发展和消费者日益增强的购买能力变化，人们生理需求得到满足，个人需求将会上升心
xxxxxxxxx 毕业设计（论文）外文文献翻译 （本科学生用） 题目：Poduct Line Engineering: The State of the Practice 生产线工程：实践的形态 学生姓名：学号： 学部（系）: 专业年级: 指导教师：职称或学位： 2011年3月10日
外文文献翻译（译成中文1000字左右）： 【主要阅读文献不少于5篇，译文后附注文献信息，包括：作者、书名（或论文题目）、出版社（或刊物名称）、出版时间（或刊号）、页码。提供所译外文资料附件（印刷类含封面、封底、目录、翻译部分的复印件等，网站类的请附网址及原文】 Requirements engineering practices A precise requirements engineering process— a main driver for successful software development —is even more important for product line engineering. Usually, the product line’s scope addresses various domains simultaneously. This makes requirements engineering more complex. Furthermore, SPL development involves more tasks than single-product development. Many product line requirements are complex, interlinked, and divided into common and product-specific requirements. So, several requirements engineering practices are important specifically in SPL development: ? Domain identification and modeling, as well as commonalities and variations across product instances Separate specification and verification for platform and product requirements ? Management of integrating future requirements into the platform and products ? Identification, modeling, and management of requirement dependencies The first two practices are specific to SPL engineering. The latter two are common to software development but have much higher importance for SPLs. Issues with performing these additional activities can severely affect the product line’s long-term success. During the investigation, we found that most organizations today apply organizational and procedural measures to master these challenges. The applicability of more formal requirements engineering techniques and tools appeared rather limited, partly because such techniques are not yet designed to cope with product line evelopment’s inherent complexities. The investigation determined that the following three SPL requirements engineering practices were most important to SPL success. Domain analysis and domain description. Before starting SPL development, organizations should perform a thorough domain analysis. A well-understood domain is a prerequisite for defining a suitable scope for the product line. It’s the foundation for efficiently identifying and distinguishing platform and product requirements. Among the five participants in our investigation, three explicitly modeled the product line requirements. The others used experienced architects and domain experts to develop the SPL core assets without extensive requirements elicitation. Two organizations from the first group established a continuous requirements management that maintained links between product line and product instance requirements. The three other organizations managed their core assets’ evolution using change management procedures and versioning concepts. Their business did not force them to maintain more detailed links between the requirements on core assets and product instances. The impact of architectural decisions on requirements negotiations. A stable but flexible architecture is important for SPL development. However, focusing SPL evolution too much on architectural issues will lead to shallow or even incorrect specifications. It can cause core assets to ignore important SPL requirements so that the core assets lose relevance for SPL development. Organizations can avoid this problem by establishing clear responsibilities for requirements management in addition to architectural roles. The work group participants reported that a suitable organizational tool for balancing requirements and architecture is roundtable meetings in which requirements engineers,