= R s - jx s = R 1 +

18 19 3 2003 5 T ransactions of the CSA E V o l. 19 N o. 3 M ay 2003,,, (, 150030) :,, 4,,,, : ; ; : S125 : A : 100226819 (2003) 0320018205 1 1 = R s - jx s = R 1 + 1gR 2 + 1gr + jξc Z = V gi ;,, Co le- Co le,, 3, [ 1 ] :, : ; 2 : F ig. 2 Equivalent circuit model of bio logical tissues, 20 40, 20 80,, 2 3 F ig. 3 R esistance m easurm ent circuit [ 2 ] [5 7 ] : (a) (b) (c) 2. 2 (d) (e) 1 : 2. 2. 1 Ε r; Ε r; tg : Ε r = cgc0; : Εr = Ε r - jε r; tg = Ε rgε r Ε r Ρ : Ρ = 2Πf Ε0Ε r = 2Πf tg Ε0Ε r 1 F ig. 1 M ethods fo r m easuring electrodes Ε r ; c ; c0 [3, 4 ] 2. 1 ; Ε0, 8. 85 10-12 Fgcm ; Ε r 2, Z ; tg ; f : 2002205223 : 2003202227 :,,,,, 150030, H z; ; Ρ, sgm ; Εr 2. 2. 2 1) :

3 : 19 Z S g Z 3 = Z bg Z 4, 3 3. 1,, 1) [ 9 15 ] : 20 40,, : Ε r tg 3c,,,,, 2) : RL C, : 4, U, C 3 Im ax = U gr, Q 1 C 1;,,, Q 2 C 2, Εr, Ε r = C S d gε0a C tg = ( 1 1 - ) : C S, C s C 1 - C 2 Q 1 Q 2, = (C 1 - C 2) ; S ; d SO 2,,,,, ; ; : G. E. M ey2 er,, [ 16 28 2) ] : 4, F ig. 4 R esonant m ethod 3) :, Ε r :, tg Ε r ; (5% 15% ) Z = A + logbx (a b 0 < b < 1), :, (30% ), ;, Ε r, tg Ε r ; : Κ Ε r : Κ=, Κ0gΕ 1g2 r, ; Ε r Θ : Ε r, (Ε r) 1g2 = 1 + A 2Θ, (Ε r) 1g3 = 1 + A 3Θ,, A 2 A 3,,, Q L RC :,,,, 3) [ 2, 9, 29 35 ] : : Ε r,,,,, 100 H z 3 10 M H z,,, ;,,, 1 M H z, ; Co le2co le

20 2003 100 H z, 100 kh z ;,, 5 100 kh z,,,, ; 33 100 kh z,,,,,, 15 kh z,,,,, 80%, [9, 36 41 ] 3. 2 2. 5 s, ; : ;, ;,,, F riono r s N o rrisd (1952),, : 2450 M H zg15, 50 kh z 1 GH z 5 kw, 2 450M H zg, P inkerton 48 kw,,,, ; :, 5 ;,, 10 kh z 1 M H z,, ; 60 3 000 M H z, ;, 0. 3 3 GH z,,,,,, : 1) Α Β Χ Α ; 2), Β, Χ, ; 3) ; 4),, ; 5) [1 50 ], 4 : [ ], [1 ]. ( 1, 2),,, ; [J ]., 1988, 35 (9): 647 653, 35 (10): 717 722. [ 2 ]. g g - g g g ( 1, 2, 3) [J ]., 1988, 50 (6): 99,, 107, 1989, 51 (5): 55 61, 1993, 55 (1): 75 83. ; [ 3 ],,. g g g g g 2 g g 2g g, g [J ]., 1987, 34 (11): 725 730. [ 4 ],. [J ]., 1997, 28 (1): 45 48.

3 : 21 [5 ]. [M ]. :, 1994. [27 ] Pow ell S D, M cl endon B D, N elson S O, et al. U se of [ 6 ],,,. den sity2independen t function and m icrow ave m easu re2 [J ]., 1997, (6): 59 63. m ent system fo r grain mo isture m easurem ent[j ]. T rans2 [ 7 ]. actopm s of the A SA E, 1988, 31 (6): 1875 1881. [J ]., 1999, 34 (2): 158 162. [28 ] N elson S O, T ian2su You. M icrow ave dielectric p roper2 [8 ],. ties of co rn and w heat kernels and soybeans[j ]. T rans2 [J ]., 1997, 32 (1): 119 121. actions of the A SA E, 1989, 32 (1): 242 249. [9 ] N elson S O. E lectrical p roperties of agricultural p roducts2 [ 29 ],,,. A critical review [J ]. T ransactions of the A SA E, 1973, 16 [J ]., 1996, 12 (3): 186 190. (2): 384 400. [30 ] N elson S O, Fo rbus W R, L aw rence K C. M icrow ave [ 10 ],, [J ]., 2000, 31 (3): 307 312. [ 11 ], [J ]., 1997, 28 (4): 321 325. [ 12 ],, [J ]., 1995, 37 (2): 162 164. [ 13 ],, [J ]., 1997, 20 (1): 71 73. [ 14 ],,. g g 2g g g g g, 1984, 55 (4): 305 309. [15 ] M eyer G E, D avison D A. A n electronic im age p lant grow th m easurem ent system [ J ]. T ransactions of the A SA E, 1987, 30 (1): 242 248. [ 16 ],, [J ]., 1990, 6 (3): 37 43. [ 17 ], [J ].., 1999, 27 (8): 7 9. [18 ] N elson S O. A m athem aticalmodel fo r estim ating the di2 electric constant of hard red w inter w heat [J ]. T ransac2 tions of the A SA E, 1985, 28 (1): 234 238. [19 ] ChariV K Kandala, L effler R G, N elson S O, et al. Ca2 perm ittivities of fresh fru its and vegetab les from 0. 2 to 20 GH z[j ]. T ransactions of the A SA E, 1993, 37 (1): 183 189.. [31 ] N elson S O. M icrow ave dielectric p roperties of fresh fruits and vegetables [J ]. T ransactions of the A SA E,. 1980, 23 (5): 1314 1317. [32 ] N elson S O. M icrow ave dielectric p roperties of fresh o2. nions[j ]. T ransactions of the A SA E, 1992, 35 (3): 963 966. [ 33 ],,,. [J ]. [J ]., 2000, 16 (3): 104 106. [ 34 ],,. [J ],, 1997, 13 (1): 202 205. [ 35 ],,. [J ]., 2001, 29 (3):. 230 234, 239. [ 36 ]. [J ].., 2000, 16 (1): 176 182. [ 37 ],,,. g g - g g g ( 1, 2 ) [J ]., 2000, 62 (3): 76 83; 2000, 62 (5): 59 69. [ 38 ],,,. [J ]., 1996, 16 (1): 62 66. [39 ] Fum ih iko tanaka, P m allikarjunan, C k im, et al. M ea2 pacitive sen so rs fo r m easu ring single2kernel m o istu re content in co rn. [J ]. T ransactions of the A SA E, 1987, 30 surem 2ent of dielectric p roperties of ch icken breast m eat (3): 793 797. [J ]. J of JSAM, 2000, 62 (4): 109 119. [20 ] N elson S O. D ensity dependence of the dielectric p roper2 [ 40 ],,. ties of particu late m aterials [ J ]. T ran saction s of the [J ]., 2000, 21 (9): 8 11. A SA E, 1983, 26 (6): 1823 1825, 1829. [41 ] Kuang W, N elson S O. L ow 2frequency dielectric p roper2 [21 ] N elson S O. A model fo r estim ating the dielectric con2 ties of b io logical tissues: A review w ith som e new in2 stant of soybeans[j ]. T ransactions of the A SA E, 1985, sigh ts [J ]. T ransactions of the A SA E, 1998, 41 (1): 173 28 (6): 2047 2050. 184. [ 22 ]. [J ]. [ 42 ]. [J ]., 1992, 8 (3): 113 119., 1998, 8 (3): 35 36. [23 ] N elson S O. Facto rs affecting the dielectric p roperties of [ 43 ],,. grain [J ]. T ransactions of the A SA E, 1982, 25 (4): 1045 [J ]., 1999, 15 (1): 90 94. 1056. [ 44 ],,. [24 ]L aw rence K C, N elson S O, K raszew sk i A W. A utom atic [J ]., 1999, 15 (3): 91 95. system fo r dielectric p roperties m easu rem en ts from [ 45 ],. [J ]. 100KH z to 1GH z [J ]. T ransactions of the A SA E, 1989,, 1997, 2: 13 14. 32 (1): 304 308. [46 ] N elson S O, Bartley P G J r, et al. R F and m icrow ave di2 [25 ]L aw rence K C, N elson S O, Bartley J r P G. M easuring di2 electric p roperties of sto red2grain insects and their imp li2 electric p roperties of hard red w inter w heat from 1 to 350 M H z w ith A flow 2th rough coaxial samp le ho lder [ J ]. cat2ions fo r po tential insect contro l[j ]. the A SA E, 1998, 41 (3): 685 692. T ransactions of T ransactions of the A SA E, 1998, 41 (1): 143 150. [ 47 ],,. [26 ] N elson S O. D ielectric p roperties m easurem ent tech2 [J ]., 2002, 28 (3): 325 330. niques and app lications[j ]. 1999, 42 (2): 523 529. [ 48 ],.

22 2003 [J ]., 1998, 19 (3): 300 304. [ 50 ],. [J ]. [ 49 ],. [J ]., 1995, 25 (77): 83 87., 1990, 11 (3): 312 317. Progress in electr ical properties of agr icultural mater ials Zha ng L i, M a Xia oyu, Le i D e tia n, Ya ng Fa ng (Colleg e of E ng ineering, N ortheast A g ricu ltu ral U niversity, H arbin 150030, Ch ina) Abstract: T he concep tion and varieties of electrical p roperties of agricu ltu ralm aterials and the m ean ing of cu rren t studies by analyzing research data are exp lained. It in troduces the m easu rem en t m ethods of electrical p roperties of agricu ltu ral m aterial, and com pares the m erits and defects of variou s m ethodṡ T he state of research and u ses of the electrical p roperties of p lan ts, an im als and m icrobes in recen t years w ere ou tlined. Som e op in ion s and sugges2 tion s fo r cu rren t and fu rther developm en ts w ere given. T hat w ill p rovide reference and gu idance fo r fu rther study the electrical p roperties and u ses of agricu ltu ral m aterialṡ Key words: agricu ltu ral m aterial; electrical p roperty; research p rogess