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BackgroundGaussian signals have symmetry and completeness, hence, the Gaussian filtering method is widely used in nuclear signal processing and radiation energy spectrum analysis. The mathematical description of Gaussian signals is relatively complex, which makes it difficult to construct digital Gaussian pulse shaping filters for nuclear pulse signal real-time processing. The commonly used digital quasi-Gaussian shaping algorithm in radiation measurement systems is derived from the differential equations of Sallen-Key and CR-(RC)n filters in analog nuclear electronics. However, its output shaping pulse signals have poor symmetry and problems such as undershoot occur when used in a single stage.PurposeThis study aims to explore the convolutional quasi-Gaussian pulse shaping filter algorithm and apply it to the processing of X-ray fluorescence measurement system experimental platform to obtain measured nuclear pulse data.MethodsFirstly, a convolutional quasi-Gaussian pulse shaping algorithm was implemented based on trapezoidal pulse signals, and bipolar pulse shaping was achieved after the initial convolution. Then, the second convolution was accumulated and summed to obtain left and right symmetric quasi-Gaussian shaping pulses. The digital recursive formula of the quasi-Gaussian pulse shaping algorithm was obtained using the Z-transform method, and the effectiveness of the algorithm and the influence of shaping parameters on the amplitude frequency characteristics were studied through simulation. Finally, quasi-gaussian shaping algorithm and trapezoidal shaping algorithm were applied separately to the offline process of measured nuclear pulse data from the X-ray fluorescence measurement system experimental platform.ResultsThe quasi-Gaussian pulse shaping filter has better high-frequency noise suppression performance compared to trapezoidal pulse shaping filters. With the increase of the values of shaping parameters na and nc, the filter passband decreases whilst the low-frequency amplitude relatively increases, and the high-frequency noise suppression effect is enhanced. However, this also leads to shaping pulse broadening and increases the probability of pulse pile-up.ConclusionsThe experimental results demonstrate that the quasi-Gaussian pulse shaping algorithm has better pile-up pulse separation ability. Under identical X-ray tube voltage and current conditions and peaking time, the energy resolution of the energy spectra obtained by both algorithms is fundamentally equivalent. However, the energy spectrum with quasi-Gaussian pulse shaping has a higher characteristic peak area.

The R-value image mapping method related to ore atomic number can identify ores more accuratelywhen applied to mineral identification, but owing to the deduction of R-value directly ignores the influence of orethickness, it is greatly affected by the thickness, so this image mapping method has certain defects. The T-value algorithm related to the thickness and density of ore retains the two important parameters, therefore, using T-value will obtained more image information. T-value image mapping method is used to verify the acquireddual energy X-ray transmission image of ore. First of all, advantages and disadvantages of the curve fittingbetween T-value and R-value recognition algorithm are compared. Through experiments, it can be seen that thecorelation coefficients of R-value curve fitting were 0.900 24 and 0.880 31, while the correlation coefficients of T-value curve fitting reach 0.998 4 and 0.991 16 respectively. Therefore, the T-value recognition algorithmrelatively reduces the influence of thickness on material recognition and the T-value algorithm is better than R-value algorithm. Therefore, an image mapping method based on T-value is proposed on the basis of this research. In which the intensity of grayscale substitution is adopted to calculate the T-value, which is then used asthe equal size image as the grayscale, and then the mathematical morphology image processing and median filtertechnology are used successively to process the image sharpness, and finally RGB pseudo-color processing is usedto obtain the final image. According to the experimental result, The T-valued image mapping method not onlyimproves the running speed compared with the R-valued image mapping method, but also better in enhancing theimage clarity and ore recognition accuracy. [ABSTRACT FROM AUTHOR]

BackgroundImpulse response shaping (IRS) of nuclear pulses is often used to obtain the quantity and time information of incident particles. It is widely used in nuclear radiation intensity measurement, high-resolution energy spectrum analysis, high counting-rate energy spectrum correction, and coincidence and anti-coincidence measurements.PurposeThe study aims to propose an IRS method for nuclear pulses obtained in high counting-rate environments.MethodsFirstly, the output signal model of the nuclear radiation detector systems was established from the principal of signal generating. Then, the digital recursive solution of the IRS algorithm was derived on the base of the derivative operation. Finally, based on the principle of RC integral shaping circuit, the method of obtaining time constants in the digital recursive solution was given. Simulated signals and acquired silicon drift detector (SDD) signals obtained from the analog-to-digital converter (ADC) were tested.ResultsExperimental results show that the proposed algorithm is superior to the traditional IRS algorithm based on Z-transform, and has better counting-rate characteristics in high counting-rate environments.ConclusionsThe new IRS algorithm is suitable for applications with different accuracy requirements and shaping speed requirements, especially suitable for impulse response shaping in high counting-rate environments.

In order to realize digital measurement and objective function assessment for joint angle, an joint angle digital measuring and functional assessing system is established and its applied algorithms is investigated. Firstly, based on Kinect data acquisition principles and calculation method of space vectors, the joint angle measuring algorithm is presented. The space points of joint on the basis of the depth data of Kinect are converted to the corresponding three-dimensional coordinates which will be used to calculate the Euclidean distance between each key point, and the joint space angles are calculated according to the angle formula of space vector. Then after the performance of several clustering methods is compared, the algorithm of function assessing by K-means is analyzed. Experimental results indicate that the system can realize the digital measuring and assessing, and the precision of the clustering indexes of purity，RI and F-meaures can be stabled in 0.8 and above. It can satisfy the system requirements of non-contact, objective, effective, higher precision and strong adaptability, as well as user-friendly control and low cost.

In order to realize the control of home appliances by gesture and real-time monitoring including alarming of indoor hazards,a smart home system based on somatosensory interaction is designed. The system captures RGBD image information by Kinect device, takes the recognized gesture information as control signal, and controls the household equipment through ZigBee LAN. At the same time, it detects the falls of the elderly or children in the scene in real time, and alarms the dangerous situation. The experimental results show that the system can meet the need of controlling the household equipment by gesture, and can detect and alarm the falling situation.

Drying is an effective method for the food industry to extend product's shelf life, which makes the moisture content of the food reduce to a certain extent to ensure microbial stability of the product. Compared to traditional air drying method, short and medium wave infrared drying takes shorter time to evaporate moisture. Water plays a critical role in the chemical and enzymatic reactions and alters material properties. Moisture transfer is therefore a governing factor in drying process. However, heat and moisture transfer in fruits and vegetables drying is a complex process. A better understanding of the mechanism of moisture transfer will be helpful to improve product quality and the efficiency of drying process. In order to investigate the changing rules of water characteristics and glass transition temperature in apple slices during short and medium wave infrared drying, low-field nuclear magnetic resonance (LF-NMR), differential scanning calorimetry (DSC) and other instruments were applied in the test. LF-NMR is commonly used to detect changes in water status with the advantages of fast and non-destructive analysis. It can explain the migration of water from microscopic point of view through its relaxation behavior of inner protons. Results showed that short and medium wave infrared temperatures had strong influence on water diffusion, and the ratio of average drying rates under 50, 70 and 90 °C was 1:1.5:2.3. Three kind of water states were obtained from the LF-NMR experiments using the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequences, and among the transverse relaxation time (T2), T21 (1-20 ms), T22 (20-200 ms) and T23 (200-1 000 ms) were corresponding to bound water, immobilized water and free water respectively, which implied that the longer the relaxation time, the stronger the water flow. The dramatically decreased content of free water content in vacuoles was accompanied by the sharp increase in the content of immobilized water in the cytoplasm and extra-cellular space, from 7.96% to 46.82%. Subsequently, the content of immobilized water decreased gradually with time increasing. Short and medium wave infrared drying elevated the glass transition temperature (P<0.05) and reduced water activity (P<0.01) appreciably by decreasing the content of immobilized water in apple tissues, which showed high correlation between glass transition temperature or water activity and water status. Obviously shrinkage occurred in apple slices along with the water loss in the process of drying, and volume and moisture content showed a significant correlation (R>0.99). This research provides the theoretical basis for understanding the water diffusion characteristics of short and medium wave infrared drying. [ABSTRACT FROM AUTHOR]

Objective: To explore the prevention and effective treatment of opposite subdural effusion after decompressive cranium., Methods: Retrospective analyses were conducted for 79 cases of opposite subdural effusion after decompressive cranium. And the efficacies of various methods were compared., Results: Among them, 78 cases were cured by enswathing with elastic bondage. And one case improved through cavity fluid drainage catheter., Conclusion: Enswathing with elastic bondage is an effective, simple and economic method of managing opposite subdural effusion after decompressive cranium.