Ultra-broadband multi-tone frequency measurement based on the recirculating frequency shift of a frequency modulated continuous wave.

We proposed an ultra-broadband multi-tone frequency measurement (FM) approach based on frequency modulated continuous wave (FMCW). This work aims to achieve wide-range multi-tone FM without image interference, using electrical components with narrow bandwidth and low sampling rate, while maintaining high FM accuracy. The FM range is largely increased by extending the bandwidth of the optical FMCW through a recirculating frequency shift (RFS) loop, from 0.001 GHz-16 GHz to 0.001 GHz-437.5 GHz. The bandwidth-extended optical FMCW coherently beats with a continuous wave (CW) light modulated by the signal under test (SUT) at the balanced photodetector (BPD). The following low-pass filter (LPF) outputs pulses at the time when the frequencies of FMCW and SUT are equal, constructing frequency-to-time mapping (FTTM). Owing to the zero-intermediate-frequency (zero-IF) architecture, image interference is avoided. In addition, the up- and down-chirps of FMCW are used to achieve self-reference, avoiding the utilizing of reference signals, which realizes high FM accuracy. In the experiment, a FM within 0.1 GHz-43.5 GHz is demonstrated using an available microwave generator (MG) with a maximum output frequency of 43.5 GHz. The FM errors are kept within ±10 MHz for all frequencies with a mean and standard deviation of -0.3 MHz and 3.17 MHz, respectively. The multi-tone resolution is about 60 MHz at the FMCW chirp rate of 3.1998 G H z/µ s, which is consistent with the theoretical result. According to the theoretical derivation, the multi-tone resolution can be improved to 1 MHz by lowering the FMCW chirp rate.

Photonic-assisted fast broadband microwave vector network analyzer based on FMCW.

In the paper, we propose a photonic-assisted fast broadband microwave vector network analyzer (FB-VNA) based on frequency modulated continuous wave (FMCW). A photonic recirculating frequency shift (RFS) loop is used to extend the bandwidth of optical FMCW. The bandwidth-extended optical FMCW beats with the continuous wave (CW) light to generate the broadband electrical FMCW, which serves as the incident signal of the device under test (DUT). The response signals of the DUT are modulated on the bandwidth-extended optical FMCW to perform de-chirping. After coherently beating the de-chirped light with the CW light, the broadband response signals of DUT are down-converted to a single-tone intermediate frequency (IF) signal carrying the frequency response of DUT, and the scattering parameters of DUT can be obtained. The single-tone IF signal relaxes the demand on the bandwidth and sampling rate of the electrical backend. Thanks to the RFS loop and the short period of FMCW, the measurement frequency range is highly extended and measurement speed is greatly accelerated at the same time, which can be applied in monitoring sudden changes of DUT features. A bandwidth multiplication of the FMCW from 6-18 GHz to 6-498 GHz is experimentally implemented. With available photodetectors (PDs) and Mach-Zehnder modulators (MZMs), a 6-54 GHz FB-VNA is demonstrated, and the S parameters of a 25-GHz low-pass filter (LPF) is measured within 6 µs. The sudden changes of S21 parameter of DUT simulated by fast adjusting the bias voltage of the MZM used for de-chirping are also characterized by the proposed FB-VNA. The sudden changes as short as 0.01 µs can be captured.

Diagnostic value of ESAT6 and CFP10 in sputum smear-negative pulmonary tuberculosis / 中国基层医药

Objective To evaluate the diagnostic value of ESAT6 and CFP10 in smear-negative pulmonary tuberculosis.Methods 32 patients of smear-negative pulmonary tuberculosis were selected as the observation group.80 cases of other non-tuberculous respiratory diseases were selected as the control group.ESAT6 and CFP10 polypeptides were used as a stimulating source,the amount of IFN-γsecreted by peripheral blood T lymphocytes was measured by ELISPOT technique.The result was compared with serum anti-tuberculosis antibody (TB-Ab).Results The positive rates of ESAT-6,CFP-10 and combination detection in the observation group were 84.4％,78.1％ and 90.6％ respectively,which were significantly higher than those in the control group,the differences were statistically significant (x2 =71.94,67.43,73.51,all P ＜ 0.01).The sensitivity (90.6％) and negative predictive value (96.1％) of ESAT6,CFP10 combined detection had no statistically significant differences compared with TB-Ab method (x2 =2.20,1.78,all P ＞ 0.05).The specificity (92.5％),positive expected value (82.9％) and the diagnostic accuracy (92.0％) of ESAT6,CFP10 combined detection were significantly higher than those of TB-Ab (60.0％,40.7 ％,62.5 ％),the differences were statistically significant (x2 =11.24,12.07,7.92,all P ＜ 0.01).The positive likelihood ratio of ESAT6,CFP10 combined detection was greater than 10 and negative likelihood ratio was less than 0.1.The possibility of diagnosis was significantly increased.Youden index co-detected by ESAT6 and CFP10 was 0.8,and that detected by TB-Ab was 0.3,indicated that the combined accuracy of ESAT6 and CFP10 was higher than TB-Ab.Conclusion Mycobacterium tuberculosis specific antigen ESAT6,CFP10 can be used as a stimulating source to stimulate effect T lymphocyte to secrete interferon-γ (IFN-γ).IFN-γ can be detected using ELISPOT.Mycobacterium tuberculosis specific antigen ESAT6,CFP10 can be used to quickly assistant the diagnosis of tuberculosis.They have higher sensitivity,specificity and good application value in the auxiliary diagnosis of smear-negative pulmonary tuberculosis.

Clinical significance of the ban nationality and kazak hepatitis B virus large surface protein detection / 中国基层医药

ObjectiveTo discuss the clinical significance of han nationality and kazak hepatitis B virus large surface protein detection.MethodsEnzyme linked immunosorbent assay(ELISA) method was used to examine the HBV-LP、HBV markers and quantitative real-time PCR methods were used to detect the HBV DNA in 270 patients with Hepatitis B.ResultsAmong the 270 cases,there was no significant difference between the levels of HBV DNA and HBV-LP( P ＞ 0.05 )in HBe Ag-positive patients,which was not affected by nationality.Significant difference of positive rate was observed between HBV-LP and HBV DNA( P ＜0.05) in HBe Ag-negative ones,which was not affected by nationality.HBV-Lp expression was significantly correlated with the logarithm of HBV DNA level ( r =0.986,P ＜ 0.05).ConclusionThere was higher coincidence rate between the levels of HBV-LP and HBV DNA in HBeAg--positive patients.The positive rate of HBV-LP was higher than that of HBV DNA in HBe Ag-negative patients.HBV-LP could serve as a reliable marker in the reflection of HBV the replication at protein level,and it was valuable to monitor HBV replication and prognosis of the disease,especially in HBe Ag-negative HBV infected patients.

Design of the automatic control system for leechdom management in hospital / 医疗卫生装备

This paper introduces the automatic control system of leechdom management in hospital by computer.It can enhance the managerial level of the medicine and reduce the cost,so the managerial level in hospital can be raised through it.