New Design of Pre-amplification Circuit for EEG Signals

In the measurement of EEG signals ,the pre - amplification electrical signal of brain is the most importantant and key link. Whether the design is excellent or inferior is related to the electrical signal detection system of brain directly. The design of this circuit has been paid attention to by domestic and international expert all the time. On the basis of existing biological electricity amplifier which is studied, the authors consult the electric amplifier circuit of living beings designed , such as reference , improve and design a new-type and high performance electrical signal characteristic of brain in . The circuit has prevented the traditional design from enlarging the miscellaneous simulation of the circuit and straining the wave link, otherwise, this circuit is of simple structure , low cost, and convenient debugging. The paper has detailed theoritic analysis and experimental results to prove this circuit, which offered a new train of thought for reseach and development of brain electrical amplifier and other faint biological electricity amplifiers . This curcuit has be expected to win extensive application.     

Design of compatible processing and analyzing system for nuclear signals

To on line detect, store and process nuclear signals with multiple forms and multiple frequencies, a compatible processing and analyzing system for nuclear signals based on ultrahigh speed data acquisition card was constructed. When the source signal is at pulse form, the system records signal with the mode of time digital converting. When source signal is at continuous form, the system records signal with the mode of analog digital converting. The processing procedures and algorithms were designed for various signal forms. The results for nuclear random process such as correlation function and power spectrum were effectively obtained.     

High speed, high precision digital phase sensitive detector design for electrical impedance tomography

Electrical impedance tomography (EIT) system must have the properties of high precision and speed, thus the digital phase sensitive detector (DPSD) based on the field programmable gate array(FPGA) is developed for data collection of EIT. Based on the principle of DPSD, the relationship between signal to noise ratio (SNR) and sample resolution as well as total number of samples is deduced. An implementation scheme of this system and a method of designing analog to digital converter (ADC) clock based on direct digital synthesis (DDS) technology are provided. The system adopts high speed multi channel ADC and low jitter clock conditioner for ADC. Real time DPSD is implemented with FPGA. The experiments show that the measurement accuracy reaches 0.03% and the SNR reaches 85 dB. The agar phantom experiments prove that the performance of the DPSD meet the designing requirement for EIT.     

黄柏苷对黄檗种子休眠程度影响的初步研究

为研究黄酮类化合物黄柏苷与环境温度、种子休眠程度的相关性,探讨黄柏苷在温度信号介导中可能存在的作用。以高效液相法检测不同生长地及年度黄檗叶片中的黄柏苷含量、滤纸培养法检测黄檗种子发芽率确定其休眠程度并持续监测生长地气温;通过在黄檗繁殖器官上喷施黄柏苷,考察黄柏苷对种子休眠程度的直接影响。结果表明,生长地花期均温相差3℃,黄檗叶片中黄柏苷含量均值相差54.46 mg/g,层积30天种子发芽率相差40.45%;不同年度间花期均温相差1.16℃,黄柏苷含量均值相差4.83 mg/g,层积30天种子发芽率相差23.07%;喷施黄柏苷,可使种子休眠程度显著加深,种子发芽率降低57.34%。研究结果提示三者之间存在环境温度越低,黄檗叶片中黄柏苷含量越高,黄檗种子休眠程度越深的关联,温度对黄檗种子休眠程度的调控可能是通过调节黄柏苷含量,经过某种体内途径实现的。     

Prediction of watermelon quality based on vibration spectrum

Judging watermelon quality based on its apparent properties such as size or skin color is difficult. A non-destructive method is employed here, based on vibrational response spectrum, to determine the quality indices of watermelon (Charleston gray). The responses of samples to vibration excitation were recorded by laser Doppler vibrometry (LDV). The phase shift between input and output signals were extracted over a wide frequency range. The total soluble solids (TSS), titratable acidity (TA) and TSS/TA ratio also measured as watermelon quality characters. Stepwise multiple linear regression (SMLR) as well as partial least square regression (PLS) was applied to extracted vibration spectrums to construct prediction models of watermelon quality. The results showed that performance of SMLR models were better than PLS. The determination coefficients (R²) of SMLR validation models were 0.9976, 0.9985 and 0.9542 for TSS, TA and TSS/TA respectively. It is likely that reduction of cell wall materials to soluble solids during ripening process changes viscoelastic properties of watermelon reflected by vibrational response. This study demonstrated the feasibility of mentioned method for predicting the quality of watermelons in an industrial grading system.     

响应辣椒疫霉菌诱导的CaWRKY转录因子筛选及其信号通路分析

在辣椒基因组中全面鉴定WRKY转录因子并筛选出受辣椒疫霉菌诱导的CaWRKY基因,并分析关键CaWRKY基因参与的信号通路。以CM334和NMCA10399为材料,基于辣椒基因组和RNA-seq数据,并在水杨酸(SA)和茉莉酸甲酯(MeJA)处理下通过qRT-PCR技术检测基因表达并分析。全基因组共鉴定出69个CaWRKY基因。接菌后12 h,抗、感材料中分别鉴定出7个和3个差异表达基因;接菌后36 h,分别有13个和22个差异表达基因,表明抗病材料能更快速应答。在筛选出的8个关键CaWRKY基因中,CaWRKY19和CaWRKY65受SA诱导上调表达;CaWRKY50受MeJA诱导上调表达;CaWRKY25受SA诱导上调表达同时受到MeJA抑制下调表达,而CaWRKY49同时受SA和MeJA抑制下调表达,推测CaWRKY19和CaWRKY65通过SA,CaWRKY50通过JA,而CaWRKY25和CaWRKY49则通过SA和JA信号途径参与辣椒抗疫病防御反应。     

Feature extraction and recognition technique for human pulse signals

In Chinese traditional medicine, the pulse signal plays an important role for diagnosis. To investigate the effective technique for identifying heroin druggers through the pulse signal, the feature extraction algorithm based on the biocepstrum and the third-order cepstrum entropy of the pulse signal is studied. On the basis of concise and rigorous discussion for the algorithm, the biocepstrum-based diagonal slice components are estimated for human pulse signals of 20 heroin druggers and 20 healthy normal subjects. The magnitude of the sample value of diagonal slice at m=n=1 and the third-order cepstrum entropy of magnitudes of sample values of the diagonal slice within a particular region are used as two feature parameters for every human pulse signal to form a feature vector. A classifier based on the criterion of squared Mahalanobis distance is successfully designed. Applying the designed classifier to 40 feature vectors, the correct identification rate reaches 87.5%. The research result shows that the method of the feature extraction and classifier design presented in is valuable for identifying the human pulse signals of heroin druggers.     

Portable ECG Monitor Front- ended Design with C8051 F020

The electrocardiogram (ECG) signal is a recording of the electrical activity on the body surface generated by the heart frequency of which is weak and low. Many researchers devote themselves to get more perfect ECG in many ways. This article introduces the characterize of an ECG signal , then discusses the requirements for the sampling circuit of an ECG. Since there are some shortcoming in common design means, the authors give an effective circuit. The system is composed of a low-cost , low-power and high-performance MCU C8051F020 , amplifier AD620 , right-leg drive circuit ,communication circuit and power management circuit. Then software design is given which is used to sampling and filtering ECG signal. Levkov filter arithmetic and smooth filter arithmetics are used in this design. In the end , the authors advance a distributing and networking ECG monitor system.     

H2S的信号分子作用及其对果蔬采后生理代谢的调控研究进展

硫化氢（H2S）作为气体信号分子,参与调控植物体的一系列生命活动,并在果蔬采后生理代谢过程中发挥着重要作用。本文综述了H2S的理化性质、发展应用历史及其在果蔬采后生理调控机制中的信号分子作用,讨论了H2S对果蔬生理代谢的调控作用,包括对果蔬采后抗逆性和品质的影响,以期为采后果蔬的贮藏保鲜提供理论参考。