CAJ | 학술논문

为实现豆浆品质快速检测和通电加热电源频率的优化，该文利用精密阻抗分析仪和DJS-10电导电极通过50 mV的激励电压在20 Hz～12 MHz频率范围内测量了不同温度（30～85℃）和不同固形物含量（1.01%～9.58%）的豆浆的交流阻抗。试验结果表明，豆浆阻抗模值与阻抗相位角随测量频率变化具有明显规律。豆浆的阻抗特性与温度以及固形物含量关系显著，且阻抗 Nyquist 图存在明显差异。在全频段，豆浆阻抗模值随着温度和固形物含量的升高而减小；在低频段，豆浆阻抗相位角随温度以及固形物含量的升高而增大；在高频段，豆浆阻抗相位角随温度以及固形物含量的升高而减小。同时，研究提出了豆浆的电阻R、电容C、恒相位元件CPE（constant phase element）三元件等效电路模型，并用ZSimpWin软件进行拟合得到了试验条件下豆浆的等效电路元件参数。基于豆浆阻抗随频率变化规律及豆浆等效电路模型分析得出，豆浆通电加热电源的频率应在300 Hz～300 kHz范围内。豆浆的等效电阻R与温度以及固形物含量之间具有良好的负指数关系。CPE参数Q值随温度的升高而降低，当固形物含量超过3.5%后，Q值随固形物含量的升高迅速增加。CPE参数n值随温度的升高而升高，但在本研究中的固形物含量范围内n值并未随固形物含量的改变发生明显变化。本研究为豆浆通电加热电源的频率选择提供了参考依据，同时为基于豆浆电特性分析实现豆浆品质的快速检测奠定基础。
위실현두장품질쾌속검측화통전가열전원빈솔적우화，해문이용정밀조항분석의화DJS-10전도전겁통과50 mV적격려전압재20 Hz～12 MHz빈솔범위내측량료불동온도（30～85℃）화불동고형물함량（1.01%～9.58%）적두장적교류조항。시험결과표명，두장조항모치여조항상위각수측량빈솔변화구유명현규률。두장적조항특성여온도이급고형물함량관계현저，차조항 Nyquist 도존재명현차이。재전빈단，두장조항모치수착온도화고형물함량적승고이감소；재저빈단，두장조항상위각수온도이급고형물함량적승고이증대；재고빈단，두장조항상위각수온도이급고형물함량적승고이감소。동시，연구제출료두장적전조R、전용C、항상위원건CPE（constant phase element）삼원건등효전로모형，병용ZSimpWin연건진행의합득도료시험조건하두장적등효전로원건삼수。기우두장조항수빈솔변화규률급두장등효전로모형분석득출，두장통전가열전원적빈솔응재300 Hz～300 kHz범위내。두장적등효전조R여온도이급고형물함량지간구유량호적부지수관계。CPE삼수Q치수온도적승고이강저，당고형물함량초과3.5%후，Q치수고형물함량적승고신속증가。CPE삼수n치수온도적승고이승고，단재본연구중적고형물함량범위내n치병미수고형물함량적개변발생명현변화。본연구위두장통전가열전원적빈솔선택제공료삼고의거，동시위기우두장전특성분석실현두장품질적쾌속검측전정기출。
In order to rapidly detect soybean milk quality and to optimize the frequency of power for ohmic heating device, the electrical impedance characteristics of soybean milk with different solid contents (ranging from 1.01%to 9.58%) at different temperatures (ranging from 30 °C to 85 °C with 5 °C interval) were measured with an impedance analyzer at a frequency ranging from 20 Hz to 12 MHz. The impedance analyzer equipped with a commercial conductivity electrode (DJS-10) was operated at a measurement voltage of 50 mV. The temperature of the soybean milk contained in a jacket beaker was controlled with water flowing through the jacket at a constant temperature. The results showed that the impedance amplitude of the soybean milk decreased with the increase in frequency at a low frequency (f<300 Hz), and the impedance amplitude of the soybean milk did not change in the middle-frequency range (300 Hz<f<300 kHz), while the impedance amplitude of the soybean milk decreased with the increase in frequency at a high frequency (f>300 kHz). The impedance phase angle decreased with the increase in frequency at the low frequency range, and it tended to be zero in the middle-frequency range, while it showed the trend of increase in the high frequencies range. The results showed that the electrical impedance of soybean milk was significantly influenced by the temperature and solid content of soybean milk. There were clear distinctions among the Nyquist plot of electrical impedance for soybean milk with different solid contents at different temperatures. The electrical impedance amplitude of the soybean milk decreased with the increase in temperature and solid content in full frequency range. The impedance phase angle of the soybean milk increased with the increase in temperature and solid content in the low frequency range, while it showed the trend of decrease in the high frequency range. An equivalent electrical circuit of soybean milk which consisted of a resistor a capacitor and a constant phase element (CPE) was built for simulating the impedance data acquired during experiments. The electrical parameters of the equivalent electrical circuit were acquired with the ZSimpWin software. By analyzing the change in the impedance of the soybean milk with the frequency, combining with the equivalent circuit model, it was concluded that the frequency of the power for ohmic heating should be in the range from 300 Hz to 300 kHz. The experimental results also showed that the equivalent resistance (R) of soybean milk decreased with the increase in the temperature and the solids content, respectively. By the regression analysis on the data, it was found that the relationship between the equivalent resistance (R) and the temperature could be described by a negative exponential function (the coefficient of determination R2 was 0.996 at the solid content of 9.58%, P<0.01), the relationship between the equivalent resistance (R) and the solid content could be also described by a negative exponential function (the coefficient of determination R2 was 0.992 at 40 °C, P<0.01). The value of Q (one of the parameters for describing the CPE) decreased with the increase in temperature;however, if the solid content of soybean milk was more than 3.5%, the value of Q increased sharply. The value of n (the other parameter for describing the CPE) increased with the increase in temperature, but it did not changed significantly with the solid content (ranged from 1.01%to 9.58%). The results in this research should be taken as a reference for selecting the frequency of the power for designing an ohmic heating system. In addition, the results also founded a method for detecting rapidly soybean milk quality on the analysis of electric parameters of soybean milk.