A High-Reliable and High-Precision Algorithm of Angle Measurement for UAV Airborne Photoelectrical Detection System

Pengfei Yuan,Daqing Huang 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.11

In order to achieve high-reliable and high-precision target measurement for UAV photoelectric detection system without increasing any costs, an algorithm of angle measurement is proposed. Firstly, by analyzing the character of grating grid image’s edge, a fast method using three gradient points to establish a parabolic function is applied for automatic grating image sub-pixel edge detection. Coarse code decoding is improved by OTSU’s method to reduce bit error rate (BER) as well as manufacturing difficulty, and a high-precision subdivision method based on observed image of grating lines is introduced to calculate subdivision angle. Secondly, simulation of BER and precision analysis show that proposed algorithm is robust in both processes of coarse code decoding and subdivision. Finally, experiment results show that BER is no more than 0.02%, the standard deviation of proposed algorithm is 1.8″ and the standard deviation of error is only 7.1″ with one reading head, indicating that proposed algorithm is robust, reliable and precise.

Experimental Study on Key Parameters of Bidirectional Cumulative Tensile Blasting with Coal-Containing Composite Roof

Pengfei Guo,Kengkeng Ye,Zhigang Tao,Hongda Liang,Yadi Yuan 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.5

To improve the effectiveness of the directional-predetermined crack blasting in the weak and alternate composite roof, this paper took the coal-containing composite roof of the 12201 working face of Halagou Coal Mine as the engineering background, and based on the technical principles of roof cutting pressure releasing gob-side entry retaining, comprehensive used of theoretical analysis, field experiments and other means, carried out in-depth research on the shaped energy blasting method and parameter design of the coal-containing composite roof. The results show: Through theoretical analysis, in the process of shaped energy blasting, the air column in the hole can reduce the peak blast pressure, which can effectively prevent the weak surrounding rock in the hole from being damaged in the non-cumulative direction and enhance the pre-splitting effect. During detonation at the bottom, the instantaneous pressure in the blast hole is lower than that of detonation at the top, and the action time of blast pressure is longer than detonation at the top. When the buried depth of the explosive (near the blast hole) is less than the critical depth, a "V"-shaped blasting funnel will be formed after the rock blasting, and the critical depth is proportional to the charge. Through field tests on the charge quantity and the length of the sealing mud, when the blast hole depth is 6m, the charge parameters of "3+2+0+1" have a better effect of energy-concentrating blasting, and the crack rate reaches 87%. Besides, field tests have shown that when shaped energy blasting is carried out on soft and hard rock formations, the stemming separation in the shaped energy tube at the interlayer position can ensure the directional pre-cracking effect of hard rock, while effectively avoiding damage to the weak rock formation in the non-cumulative direction.

Anesthetic Management and Outcomes of Endovascular Treatment of Basilar Artery Occlusion: Results From the ATTENTION Registry

Tao Chunrong,Yuan Guangxiong,Xu Pengfei,Wang Hao,Zhou Peiyang,Yi Tingyu,Li Kai,Cui Tao,Gao Jun,Li Rui,Sun Jun,Zhang Chao,Wang Li,Liu Tianlong,Song Jianlong,Yin Yamei,Nguyen Thanh N.,Li Qing,Hu Wei 대한뇌졸중학회 2023 Journal of stroke Vol.25 No.3

Background and Purpose To examine the clinical and safety outcomes after endovascular treatment (EVT) for acute basilar artery occlusion (BAO) with different anesthetic modalities. Methods This was a retrospective analysis using data from the Endovascular Treatment for Acute Basilar Artery Occlusion (ATTENTION) registry. Patients were divided into two groups defined by anesthetic modality performed during EVT: general anesthesia (GA) or non-general anesthesia (non-GA). The association between anesthetic management and clinical outcomes was evaluated in a propensity score matched (PSM) cohort and an inverse probability of treatment weighting (IPTW) cohort to adjust for imbalances between the two groups. Results Our analytic sample included 1,672 patients from 48 centers. The anesthetic modality was GA in 769 (46.0%) and non-GA in 903 (54.0%) patients. In our primary analysis with the PSM-based cohort, non-GA was comparable to GA concerning the primary outcome (adjusted common odds ratio [acOR], 1.01; 95% confidence interval [CI], 0.82 to 1.25; <i>P</i>=0.91). Mortality at 90 days was 38.4% in the GA group and 35.8% in the non-GA group (adjusted risk ratio, 0.95; 95% CI, 0.83 to 1.08; <i>P</i>=0.44). In our secondary analysis with the IPTW-based cohort, the anesthetic modality was significantly associated with the distribution of modified Rankin Scale at 90 days (acOR: 1.45 [95% CI: 1.20 to 1.75]). Conclusion In this nationally-representative observational study, acute ischemic stroke patients due to BAO undergoing EVT without GA had similar clinical and safety outcomes compared with patients treated with GA. These findings provide the basis for large-scale randomized controlled trials to test whether anesthetic management provides meaningful clinical effects for patients undergoing EVT.

Collisional dynamics in laser-induced plasmas: evidence for electron-impact excitation

Zhang, Liying,Wei, Pengfei,Qin, Meiyan,Yuan, Xiaolong,Liu, Candong,Geng, Tao,Zhu, Haiyong,Duan, Yanmin,Zhuang, Songlin,Lu, Peixiang,Kim, Dong Eon The Optical Society 2018 Optics express Vol.26 No.8

Relative humidity-dependent viscosity of secondary organic material from toluene photo-oxidation and possible implications for organic particulate matter over megacities

Song, Mijung,Liu, Pengfei F.,Hanna, Sarah J.,Zaveri, Rahul A.,Potter, Katie,You, Yuan,Martin, Scot T.,Bertram, Allan K. Copernicus GmbH 2016 Atmospheric Chemistry and Physics Vol.16 No.14

<P>Abstract. To improve predictions of air quality, visibility, and climate change, knowledge of the viscosities and diffusion rates within organic particulate matter consisting of secondary organic material (SOM) is required. Most qualitative and quantitative measurements of viscosity and diffusion rates within organic particulate matter have focused on SOM particles generated from biogenic volatile organic compounds (VOCs) such as α-pinene and isoprene. In this study, we quantify the relative humidity (RH)-dependent viscosities at 295 ± 1 K of SOM produced by photo-oxidation of toluene, an anthropogenic VOC. The viscosities of toluene-derived SOM were 2 × 10−1 to ∼ 6 × 106 Pa s from 30 to 90 % RH, and greater than ∼ 2 × 108 Pa s (similar to or greater than the viscosity of tar pitch) for RH ≤ 17 %. These viscosities correspond to Stokes-Einstein-equivalent diffusion coefficients for large organic molecules of ∼ 2 × 10−15 cm2 s−1 for 30 % RH, and lower than ∼ 3 × 10−17 cm2 s−1 for RH ≤ 17 %. Based on these estimated diffusion coefficients, the mixing time of large organic molecules within 200 nm toluene-derived SOM particles is 0.1-5 h for 30 % RH, and higher than ∼ 100 h for RH ≤ 17 %. As a starting point for understanding the mixing times of large organic molecules in organic particulate matter over cities, we applied the mixing times determined for toluene-derived SOM particles to the world's top 15 most populous megacities. If the organic particulate matter in these megacities is similar to the toluene-derived SOM in this study, in Istanbul, Tokyo, Shanghai, and São Paulo, mixing times in organic particulate matter during certain periods of the year may be very short, and the particles may be well-mixed. On the other hand, the mixing times of large organic molecules in organic particulate matter in Beijing, Mexico City, Cairo, and Karachi may be long and the particles may not be well-mixed in the afternoon (15:00-17:00 LT) during certain times of the year. </P>

Tracklet-Global Track Fusion Using Support Degree Function in Sensor Networks

Xiaobin Li,En Fan,Changhong Yuan,Pengfei Li 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.10

For the situation with unknown qualities of local tracks in sensor networks, a new tracklet-global track fusion method using the support degree function (SDF-T2GTF) is proposed. According to the characteristic of actual transmission modes, two local estimates of a moving target in adjacent interval transmitted by the same local node are defined as a tracklet, and subsequently tracklet-global track (T2GT) fusion can replace the traditional track fusion in the global node, namely local track-global track (LT2GT) fusion. Considered the advantage of the fuzzy track association (TA) method for unknown prior information of local tracks, it is used in T2GT association. Then all correlated tracklets in the same interval can be mapped into a set of points in parameter space by the Hough transform (HT) algorithm. The support degree function of these points is utilized to dynamically estimate the qualities of tracklets and reasonably allocates the weights of local estimates in fusion results. Hence, the proposed method can realize T2GT fusion without the prior information of local tracks. The experimental result illustrates that the proposed method can satisfy the requirement of data transmission in real systems, and can realize T2GT fusion; on the other, it can improve the performance of track fusion in accuracy compared with the traditional methods.

Trace surface fluorination and tungsten-intercalation cooperated dual modification induced photo-activity enhancement of titanium dioxide

Yifan Xu,Zhongyuan Liu,Kunlun Wang,Chunyao Niu,Pengfei Yuan,Jin You Zheng,Young Soo Kang,Xiao Li Zhang 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-

General modification that utilizes insoluble tungstic acid or highly toxic hydrofluoric acid to improvecharge separation and transfer in TiO2 results in considerable issues such as uneven doping, significantimpacts on particle size and morphology, as well as environmental hazards. In the present work, an environmentalbenign one-pot dual-modification approach was demonstrated that uses soluble sodium tungstateand only trace-level sodium fluoride as replacements. The photoactivity efficiency for decolorationof methylene blue (MB) solution was improved by 33.6% and 119.5% under ultraviolet and visible light,respectively. Meanwhile, the photocurrent density reached an enhancement by 181.2% by this dualmodification. The dual-modification had negligible influence on the crystal structure and the surface areaof the TiO2 nanoparticles. Density functional calculation suggested the remarkable improvements of thephotocatalysis of TiO2 can be ascribed to the rapid charge separation and transfer owing to the downshiftof conduction band from the tungsten doping and localized spatial charge separation from the surfacefluorination enabled by the dual-modification approach.