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A high performance waveform and a new ranging method for the proximity detector

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Defence Technology（防务技术） 2020年第4期16卷 834-845页

作者： Qi-le Chen Xin-hong Hao xiao-peng yan Ping Li School of Mechatronical Engineering Beijing Institute of TechnologyBeijing 100081China

Signal modulation is an essential design factor for proximity detectors and directly affects the system's potential *** order to achieve the advantages of chaotic codes bi-phase modulation(CCBPM)and linear frequency modulation(LFM) simultaneously,this paper designed a waveform which combined chaotic codes bi-phase modulation and linear frequency modulation(CCBPM-LFM) for proximity *** CCBPM-LFM waveform was analyzed in the aspect of time delay resolution(TDR) and Doppler tolerance(DT) based on ambiguity function(AF).Then,a ranging method,which we called instant correlation harmonic demodulation(ICHD),was presented for the detector using the CCBPM-LFM *** combining time domain instant correlation with harmonic demodulation,the ICHD solved the problem caused by combination modulation and made the most of the linear frequency modulation(LFM) harmonics and the correlation of chaotic ***,a prototype was implemented and ranging experiments were carried *** the theoretical analysis and experimental results,the proximity detector used the CCBPM-LFM waveform has an outstanding detection performance.

关键词： Proximity detectors Detection performance Combination modulation Chaotic codes bi-phase modulation Linear frequency modulation

Optical Coherence Tomography Features of Tuberculous Serpiginous-like Choroiditis and Serpiginous Choroiditis

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Biomedical and Environmental Sciences 2018年第5期31卷 327-334页

作者： wang xiao na you qi sheng zhao hui ying peng xiao yan Beijing Institute of Ophthalmology Beijing Tongren Eye Center Beijing Ophthalmology and Visual Science Key Lab Beijing Tongren Hospital Capital Medical University Beijing 100730 China

Objective To investigate optical coherence tomography（OCT） characteristics of tuberculous serpiginous-like choroiditis（Tb-SLC） and serpiginous choroiditis（SC） and to perform OCT to differentiate between these *** This retrospective,case-control study examined consecutively enrolled patients with active Tb-SLC or *** underwent comprehensive ocular examinations and imaging（OCT,color fundus photography,autofluorescence imaging,fluorescein angiography,and indocyanine green angiography）.Findings were examined and compared between eyes with SC and *** Nine patients with active Tb-SLC（14 eyes） and 8 with active SC（12 eyes） were *** following OCT findings were observed significantly more often in the Tb-SLC group than in the SC group： vitreal hyper-reflective spots [5 Tb-SLC eyes（36%）,no SC eyes：P = 0.02],intraretinal edema [11 Tb-SLC eyes（79%）,3 SC eyes（25%）：P = 0.01],sub-retinal pigment epithelium（RPE） drusenoid deposits [11 Tb-SLC eyes（79%）,2 SC eyes（17%）：P 〈 0.01],and choroidal granulomas [8 Tb-SLC eyes（57%）,2 SC eyes（17%）：P = 0.03].A hyporeflective,wedge-shaped band was observed more often in the SC group [5 Tb-SLC eyes（36%）,9 SC eyes（75%）：P = 0.045] than in the Tb-SLC *** incidence of other OCT signs did not differ between the groups and included outer nuclear layer hyper-reflection,outer retinal tabulation,and choriocapillaris point-like *** Vitreal hyper-reflective spots,intraretinal fluid,sub-RPE drusenoid deposits,and choroidal granulomas on OCT images may indicate ***,a hyporeflective,wedge-shaped band may indicate ***,OCT is likely helpful in differentiating between Tb-SLC and SC.

关键词： Optical coherence tomography Choroiditis Serpiginous Tuberculosis

Repeater jamming suppression method for pulse Doppler fuze based on identity recognition and chaotic encryption

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Defence Technology（防务技术） 2021年第3期17卷 1002-1012页

作者： Jian Dai Xin-hong Hao Qiang Liu xiao-peng yan Ping Li Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China Ordnance Science Institute of China Beijing 100089China

Pulse Doppler(PD) fuze is widely used in current battlefield. However, with the threat of repeater jamming, especially digital radio frequency memory technology, the deficiency in the anti-repeater jamming of a traditional PD fuze increasingly emerges. Therefore, a repeater jamming suppression method for a PD fuze based on identity(ID) recognition and chaotic encryption is proposed. Every fuze has its own ID which is encrypted with different chaotic binary sequences in every pulse period of the transmitted signal. The thumbtack-shaped ambiguity function shows a good resolution and distance cutoff characteristic. The ability of anti-repeater jamming is emphatically analyzed, and the results at different signal-to-noise ratio(SNR) show a strong anti-repeater jamming ability and range resolution that the proposed method possesses. Furthermore, the anti-repeater jamming ability is influenced by processing gain, bit error rate(BER) and correlation function. The simulation result validates the theoretical analysis, it shows the proposed method can significantly improve the anti-repeater jamming ability of a PD fuze.

关键词： Pulse Doppler fuze ID Chaotic binary code Encryption Repeater jamming

Adaptive target and jamming recognition for the pulse doppler radar fuze based on a time-frequency joint feature and an online-updated naive bayesian classifier with minimal risk

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Defence Technology（防务技术） 2022年第3期18卷 457-466页

作者： Jian Dai Xin-hong Hao Ze Li Ping Li xiao-peng yan Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing100081China

This paper considers the problem of target and jamming recognition for the pulse Doppler radar fuze(PDRF).To solve the problem,the matched filter outputs of the PDRF under the action of target and jamming are ***,the frequency entropy and peak-to-peak ratio are extracted from the matched filter output of the PDRF,and the time-frequency joint feature is *** on the time-frequency joint feature,the naive Bayesian classifier(NBC)with minimal risk is established for target and jamming *** improve the adaptability of the proposed method in complex environments,an online update process that adaptively modifies the classifier in the duration of the work of the PDRF is *** experiments show that the PDRF can maintain high recognition accuracy when the signal-to-noise ratio(SNR)decreases and the jamming-to-signal ratio(JSR)***,the applicable analysis shows that he ONBCMR method has low computational complexity and can fully meet the real-time requirements of PDRF.

关键词： Pulse Doppler radar fuze(PDRF) Target and jamming recognition Time-frequency joint feature Online-update naive Bayesian classifier minimal risk(ONBCMR)

Air target recognition method against ISRJ for radio frequency proximity sensors using chaotic stream encryption

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Defence Technology（防务技术） 2023年第10期28卷 267-279页

作者： Jian-feng Li Jian Dai Xin-hong Hao xiao-peng yan Xin-wei Wang Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing100081China BIT Tangshan Research Institute Beijing100081China

The interrupted-sampling repeater jamming(ISRJ)can cause false targets to the radio-frequency proximity sensors(RFPSs),resulting in a serious decline in the target detection capability of the *** article proposes a recognition method for RFPSs to identify the false targets caused by *** proposed method is realized by assigning a unique identity(ID)to each RFPS,and each ID is a periodically and chaotically encrypted in every pulse *** processing technique of the received signal is divided into ranging and ID *** the ranging part,a high-resolution range profile(HRRP)can be obtained by performing pulse compression with the binary chaotic *** suppress the noise,the singular value decomposition(SVD)is applied in the *** ID decryption,targets and ISRJ can be recognized through the encryption and decryption processes,which are controlled by random *** adaptability analysis conducted in terms of the peak-to-side lobe ratio(PSLR)and bit error rate(BER)indicates that the proposed method performs well within a 70-k Hz Doppler shift.A simulation and experimental results show that the proposed method achieves extremely stable target and ISRJ recognition accuracies at different signal-to-noise ratios(SNRs)and jamming-to-signal ratios(JSRs).

关键词： Interrupted-sampling repeater jamming(ISRJ) Radio frequency proximity sensors(RFPS) Chaotic stream encryption Air target recognition Identity(ID)decryption

Formation of ZrB2in MgO-C Composite Materials Using In-Situ Synthesis Method

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Journal of Iron and Steel Research International 2006年第1期13卷 70-74页

作者： LI Lin HONG yan ruo SUN Jia-lin HE Zhi-yong peng xiao-yan Refractory Division Central Iron and Steel Research Institute Beijing 100081 China School of Materials Science and Engineering University of Science and Technology Beiiing Beiiing 100083 China

ZrB2 in MgO-C composite materials obtained by both microwave sintering synthesis and in-situ reaction at lower temperature was investigated. The test result shows that 66.67 % of reactant changed into Zrb2, and the other form Al2O3, which could optimize the properties of carbon containing materials. Therefore, the method of in situ synthesizing ZrB2 acting as antioxidant in carbon containing materials is considered as one of best ways to reduce the cost and ZrB2 as refractories is used on a large-scale.

关键词： ZrB2 microwave in situ synthesis carbon containing material

Weak wide-band signal detection method based on small-scale periodic state of Duffing oscillator

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Chinese Physics B 2018年第3期27卷 205-215页

作者： Jian Hou xiao-peng yan Ping Li Xin-hong Hao Science and Technology on Electromechanical Dynamic Control Laboratory School of Mechatronical Engineering Beijing Institute of Technology Beijing 100081 China

The conventional Duffing oscillator weak signal detection method, which is based on a strong reference signal, has inherent deficiencies. To address these issues, the characteristics of the Duffing oscillator＇s phase trajectory in a small- scale periodic state are analyzed by introducing the theory of stopping oscillation system. Based on this approach, a novel Duffing oscillator weak wide-band signal detection method is proposed. In this novel method, the reference signal is discarded, and the to-be-detected signal is directly used as a driving force. By calculating the cosine function of a phase space angle, a single Duffing oscillator can be used for weak wide-band signal detection instead of an array of uncoupled Duffing oscillators. Simulation results indicate that, compared with the conventional Duffing oscillator detection method, this approach performs better in frequency detection intervals, and reduces the signal-to-noise ratio detection threshold, while improving the real-time performance of the system.

关键词： Duffing oscillator weak signal detection stopping oscillation system small-scale periodic state

Novel magnetic compression technique for establishment of a canine model of tracheoesophageal fistula

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World Journal of Gastroenterology 2019年第30期25卷 4213-4221页

作者： Yi Gao Rong-Qian Wu Yi Lv xiao-peng yan Department of Hepatobiliary Surgery The First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061Shannxi ProvinceChina National Local Joint Engineering Research Center for Precision Surgery and Regenerative Medicine The First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061Shannxi ProvinceChina

BACKGROUND Clinically,tracheoesophageal fistula(TEF)is lack of effective surgical *** reason is due to the lack of appropriate animal models of acquired TEF,which is usually complex and ***,the magnetic compression technique has been applied for digestive tract anastomosis or vascular anastomosis in *** this study,an animal model of TEF in dogs was developed by using the magnetic compression technique,hoping to provide a new method for mimicking *** To establish a TEF model in dogs by using the magnetic compression *** Six male beagles were used as models with two Nd-Fe-B permanent magnets for *** parent magnet and the daughter magnet were placed in the cervical esophagus and trachea,*** anterior wall of the esophagus and the posterior wall of the trachea were compressed when the two magnets *** 4-6 d,the necrotic tissue between the two magnets fell off and the parent and daughter magnets disengaged from the target location,leaving a ***/bronchoscopy,upper gastrointestinal contrast study,and histological analysis were *** The establishment of the TEF model in all six beagles was *** average time of magnet placement was 4.33±1.11 min(range,3-7 min).Mean time for the magnets to disengage from the target location was 4.67±0.75 d(range,4-6 d).TEFs were observed by gastroscopy/bronchoscopy and esophageal *** gross anatomical structure of the esophagus and the trachea was in good *** was no esophageal mucosa or pseudostratified ciliated columnar epithelium at the site of the fistula according to histological *** It is simple,feasible,and minimally invasive to use the magnetic compression technique for the establishment of the TEF model in dogs.

关键词： Magnetic compression technique Tracheoesophageal fistula Beagle Animal model

Influence of different magnetic forces on the effect of colonic anastomosis in rats

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World Journal of Gastrointestinal Surgery 2024年第3期16卷 860-870页

作者： Bo-yan Tian Miao-Miao Zhang Jia Ma Yi Lyu xiao-peng yan Department of Hepatobiliary Surgery The First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an 710061Shaanxi ProvinceChina National Local Joint Engineering Research Center for Precision Surgery&Regenerative Medicine The First Affiliated Hospital of Xi'an Jiaotong UniversityXi'an 710061Shaanxi ProvinceChina Department of Surgical Oncology Shaanxi Provincial People's HospitalXi'an 710068Shaanxi ProvinceChina

BACKGROUND Despite much work having been conducted on magnetic compression anastomo-sis(MCA)in the digestive tract,there are no reports on the influence of magnetic force on the *** To investigate the effect of different magnetic force magnets on the MCA of the digestive *** Two groups of magnets of the same sizes but different magnetic forces were designed and produced.A total of 24 Sprague-Dawley rats were randomly assigned into two groups(powerful magnet group and common magnet group),with 12 rats in each *** types of magnets were used to complete the colonic side-to-side anastomosis of the *** operation time and magnet discharge time were *** anastomotic specimens were obtained 4 wk after the operation and then the burst pressure and diameter of the anastomosis were measured,and the anastomosis was observed via the naked eye and subjected to histological *** The magnetic forces of the powerful and common magnet groups at zero distance were 8.26 N and 4.10 N,*** colonic side-to-side anastomosis was completed in all 24 rats,and the operation success rate and postoperative survival rate were 100%.No significant difference was noted in the operation time between the two *** magnet discharge time of the powerful magnet group was slightly longer than that of the common magnet group,but the difference was not statistically significant(P=0.513).Furthermore,there was no statistical difference in the burst pressure(P=0.266)or diameter of magnetic anastomosis(P=0.095)between the two *** gross specimens of the two groups showed good anastomotic healing,and histological observation indicated good mucosal continuity without differences on *** In the rat colonic side-to-side MCA model,both the powerful magnet with 8.26 N and the common magnet with 4.10 N showed no significant impact on the anastomosis establishment process or its effect.

关键词： Magnetosurgery Magnetic compression anastomosis Colonic anastomosis Magnetic force Rats