[Design of Noninvasive Blood Constituent Spectrum Data Acquisition System Based on FPGA].

Blood constituent examination is an important means of health diagnosis. For blood constituent examination, we usually adopt the method of drawing blood, which bring pain and the risk of cross infection to the patient. Near infrared spectrum spectroscopy (NIRS) is a research hotspot in noninvasive blood constituent examination.

[Design of high-efficiency double compound parabolic concentrator system in near infrared noninvasive biochemical analysis].

High signal-to-noise ratio (SNR) of system is necessary to obtain accurate blood components in near infrared noninvasive biochemical analysis. In order to improve SNR of analytical system, high-efficiency double compound parabolic concentrator (DCPC) system was researched, which was aimed at increasing light utilization efficiency. Firstly, with the request of collection efficiency in near infrared noninvasive biochemical analysis, the characteristic of emergent rays through compound parabolic concentrator (CPC) was analyzed.

[Experimental study of differential spectrum method for elimination of tissue background in noninvasive biochemical detection].

In noninvasive biochemical detection, the differential spectrum method based on the change in blood volume can eliminate the interference of human tissue background in theory, and obtain effective spectrum information of blood. In order to demonstrate the effectiveness of the differential spectrum method, simulated experiment was designed. Biological molecules solutions were used for simulating serum sample, filters with different absorption characteristic were used for simulating interference of tissue background, and an adjustable path-length cell was used for simulating blood volume change.

[Effect of path-length variations on PLSR calibration model in noninvasive measurement of blood glucose by mid-infrared spectroscopy].

In noninvasive blood glucose measurement, it is difficult to keep the contact area between skin and internal reflectance element uniform while the mid-infrared spectra of human skin are taken, and this would lead to path-length variations. To study the effect of path-length variations on PLSR calibration model, in the present paper, according to the correlation coefficients between path-lengths and glucose concentrations, two PLSR models were achieved respectively and RMSECV were 31.3 and 4.

[Research progress and application prospect of near infrared spectroscopy in soil nutrition analysis].

"Digital agriculture" or "precision agriculture" is an important direction of modern agriculture technique. It is the combination of the modern information technique and traditional agriculture and becomes a hotspot field in international agriculture research in recent years. As a nondestructive, real-time, effective and exact analysis technique, near infrared spectroscopy, by which precision agriculture could be carried out, has vast prospect in agrology and gradually gained the recognition.

[Progress in noninvasive biochemical examination by near infrared spectroscopy].

In the early nineties of last century, great importance had been gradually attached to the potential of near-infrared spectroscopy (NIRS) in the human body noninvasive biochemical examination. However, the human body is extremely complex. Although research teams have made some achievements in experimental simulations and in-vitro analysis, there is still no substantive breakthrough in clinical application now.

[Research on the effective signal extraction in the noninvasive blood glucose sensing by near infrared spectroscopy].

Diabetes seriously endanger human health, and noninvasive glucose sensing is the expectation of both doctors and patients. Physiological background is complicated, volatile and mixed with a variety of tissue information, resulting in direct measurement of the body's near infrared spectra difficult to truly reflect the concentration change in glucose. As a matter of fact, blood volume is always changing, but human tissue background and the concentration of blood components are constant in a short period.

[Choice of characteristic near-infrared wavelengths for soil total nitrogen based on successive projection algorithm].

The present paper proposed how to select characteristic near-infrared wavelength for soil total nitrogen by using successive projection algorithm (SPA). Spectral data are compressed by SPA in the first place to obtain the raw wavelengths. Then the group of wavelengths derived from SPA is screened by their contributions to the total nitrogen.