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As one of the most fundamental and challenging tasks in computer vision, target detection aims to find out specific targets in images and to locate and classify them, and is now widely used in many fields such as industrial quality inspection, video surveillance and unmanned vehicles. In recent years, with the breakthroughs in computer hardware resources and depth convolution algorithms in image classification tasks, depth convolution-based target detection algorithms have gradually replaced the traditional target detection algorithms and achieved significant results in terms of accuracy and performance. This paper reviews the current research status of depth convolution-based target detection algorithms and possible future development directions. It introduces the authoritative datasets and evaluation metrics of target detection algorithms with the limitations of traditional target detection algorithms as a guide, and then reviews the research and development history of representative algorithms for depth convolution-based target detection in recent years with time and algorithm architecture as the main research lines. The network structures of one-stage, two-stage and other improved algorithms are compared and analyzed, and the characteristics, advantages and limitations of various target detection algorithms are summarized. Finally, the future trends are prospected in the light of current problems and challenges of target detection.

In order to verify that the deformation of coal body is the superposition of coal matrix adsorption expansion (desorption shrinkage) deformation and effective stress deformation, based on the mechanism of adsorption swelling deformation, the verification method of superposition relationship of coal deformation under adsorption was proposed. The superposition relationship of coal deformation under adsorption is verified by using this method combined with experimental data. The results showed that the average relative error of theoretical value and experimental value proportion coefficient of isothermal adsorption experiment of anthracite, lean coal and 1/3 coking coal is 4.27%. The deformation of coal body, the adsorption expansion deformation of coal matrix and the deformation of coal body under the effective stress are in accordance with the superposition relationship. Through discussion, it is concluded that the verification method of superposition relation of coal deformation is suitable for reversible deformation and residual deformation of desorption curve, but not for rich deformation.

In order to prevent coal spontaneous combustion, a new type mine fire extinguishing gel which consists of sodium carboxymethylcellulose, zirconium citrate and gluconic-δ-lactone has been developed. The gelation time of different ratios of gel components was tested and the optimum fire-extinguishing ratio suitable for coal mine under different conditions was determined. Then the water loss rate of the gel was tested, the results show that the gel has good thermal stability and strong water retention ability. The temperature-programming experiment shows that the addition of gel reduces the oxygen consumption rate and the production of CO during coal spontaneous combustion, which can suppress the oxidation process of coal. The influence of gel on coal activation energy was calculated and analyzed by thermogravimetric curves, the results show that the addition of gel increases the energy required for coal-oxygen reaction and increases the difficulty of the reaction. FTIR was also used introduced to analyze the effect of gel on active groups of coal during heating coal oxidation, the results show that the addition of the gel inhibits the conversion of C-H components to oxygen-containing functional groups, and reduces the number of active functional groups, inhibits the oxidation reaction of coal.

The Nuri deposit is located at the south margin of the Gangdese metallogenic belt in Tibet. Its mineralization age revealed by Re-Os dating of molybdenite is 23 Ma, which is consistent with that of the Mingze and Chengba deposits. However, the ore-related rocks have not yet been identified. In this study, we report the age and geochemistry of the newly discovered quartz diorite related to mineralization. LA-ICP-MS zircon U-Pb dating indicates that the diorite intruded at 93.42±0.76 Ma. The age is consistent with the ages of Shangbujiala(93 Ma) and Kelu(90 Ma) copper-gold deposits in the same metallogenic belt. These ages and previous ages indicate a two-stage ore-forming process. Major elemental analysis shows that quartz diorites contain 57.19%-58.23% SiO2, 15.78-16.03% A12O3, and 4.74%-5.32% MgO, with Mg# indicators of 65.2-67.3. Trace element composition suggests that these rocks are rich in large ion lithophile elements and light rare earth elements, but are poor in high field-strength elements, characteristic of adakite. This study indicates that quartz diorites are arc magmatic rocks formed in the stage of oceanic crust subduction. The primary magma formed by melting of oceanic crust intruded at the shallow crust, resulting in the formation of early skarn copper deposit. The identification of two stages of mineralization in the Nuri deposit expands the prospecting direction of the study area.

The Zhaxikang Pb-Zn polymetallic ore deposit, the first SEDEX-modified by hot spring type Mn-Fe-Sb-Pb-Zn-Ag deposit discovered in China, is associated with Pb, Zn, Ag, Sb, Cu, S, Mn, As and other elements. The concentration, mineral species, dissemination and inclusion of Mn in the Zhaxikang Pb-Zn deposit were studied by chemical analysis and examination using Petrographic Microscope, Scanning Electron Microscope and X-ray Diffractometry. The analysis showed that the content of ore-forming elements Pb and Zn were 6% and 4%, and the content of the associated component Mn was 4.36%. The main mineral compositions of the Zhaxikang Pb-Zn polymetallic ore deposit are galena, sphalerite, pyrite, arsenopyrite and rhodochrosite. The useful composition of manganese minerals in the mine mostly occurs as rhodochrosite and iron rhodochrosite, which closely associated with sphalerite and galena, an important carrier of mineralization stage, inlay on the edge, intergranular and gap between quartz, pyrite, sphalerite and arsenopyrite. The others occur in siderite and smithsonite with isomorphism forms. The content and occurrence of Mn in Zhaxikang Pb-Zn ore metallurgical produts were analysised, which shows that the comprehensive utilization of Mn is of high value. The mass fraction of Mn in the lead ore, lead concentrate, zinc concentrate and tailings was 4.36%, 0.51%, 0.95% and 5.36%, respectively, indicating that little Mn enters into lead concentrate and zinc concentrate, but mostly in tailings. Mn is mainly in rhodochrosite form in lead-zinc tailings, which can be comprehensively recovered and utilized by a high intensity magnetic separation process.

The Kulagangri Dome is located at the eastern part of the Himalayan metallogenic belt. Based on the 1 :50 000 mineral geological mapping and sparse surface engineering, the Gabo pegmatite-type lithium deposit was firstly found at the eastern part of the Kulagangri Dome. Ore-bearing spodumene pegmatite dikes are generally hosted by the marble in the middle unit of the dome, with length ranging from 1 m to 1 200 m, and width ranging from 0. 8 m to 40 m. The main lithium containing minerals in the spodumene pegmatite are spodumene, elbaite and lepidolite. At present, two main Li mineralization zones are controlled by 5 surface engineering. The mineralization zone I is about 2 km long, and includes 2 main orebodies (K1 and K2). The mineralization zone II is about 700 m long, and include one main orebody (K3). The K1 orebody is about 1 200 m long and 5 ~ 40 m thick, with an average thickness of about 20 m. The K2 and K3 orebodies occur as the large lenticular shape, with strike extension >100~600 m and thickness 15~50 m. The total thickness of K2 orebody is 45. 3 m. The average grade of Li2O, Rb2O and BeO is 1.11%, 0.064% and 0.047%, respectively. The newly discovered Gabo lithium deposit is dominated by Li, Be and Rb, associated with Nb, Ta, Cs, W and Sn. Based on the geological survey results, the Gabo lithium deposit is large in scale, and showing considerable potential for further prospecting in the area. The discovery of Gabo lithium deposit is another breakthrough in the exploration of rare metals in the Himalayan metallogenic belt, which is of great significant role in further understanding of the tectono-magmatic evolution and rare metal mineralization in the Cenozoic Himalaya, and further enriching the theory of collisional orogenesis and mineralization in the southern Qinghai-Tibet Plateau. [ABSTRACT FROM AUTHOR]

In order to reduce influence of underground environment on the positioning system,this paper presented a fingerprint positioning algorithm based on SVM classification. The algorithm consists of fingerprint database, underground tunnel fingerprint data acquisition and underground location matching. The SVM classification method was adopted to establish the fingerprint database, the singular value was removed to eliminate the effects of dynamic fingerprints, the best match position was found by matching the real-time sampling signal to the fingerprint database. This paper collected 50 samples by randomly fingerprint data as position information, muti-terminal user position information was measured and five user terminals measurement data were taken for analysis. The results of location experiments showed that the positioning error of proposed algorithm was less than 1.5 m, which was much better than traditional positioning algorithm based on RSSI. [ABSTRACT FROM AUTHOR]

Objective To investigate the effects of high-salt medium on the expression of endothelial nitric oxide synthase (eNOS) and related mechan-sms in EA. Hy926 cell line. Methods EA. hy926 cells were treated 48 h with different concentrations of high-salt medium; 137 mmol/L was selected as the target concentration intervention in further experiment. The cells were divided into four groups which received intervention for 48 h: DMEM high-glucose medium group (sodium chloride concentration of 109 mmol/L), high-salt medium (sodium chloride concentration of 137 mmol/L), high-salt medium (sodium chloride concentration of 137 mmol/L) + RNA interference, and hypertonic control group (mannitol concentration of 56 mmol/L). High-performance liquid chromatography was used to assay ADMA concentration in cell supernatant; real-time quantitative PCR and Western blot were used to assay the expressions and actvities of PRMT-1, RhoA, ROCK and eNOS. Results ADMA concentration, PRMT-1 expression, the mRNA expression of RhoA and ROCK actvity increased significantly whereas the protein expression of eNOS significantly reduced in the high-salt group compared with those in the two control groups. High-sat medium + RNA interference restored the above biochemical indicators and upregulated the protein expression of eNOS significantly. Conclusion High-sat medium induces ADMA-mediated RhoA/ Rock-1 pathway activation and suppresses eNOS generation. [ABSTRACT FROM AUTHOR]

The article presents a study which discusses the effects of different alloy contents on corrosion resistance of coatings. It observes the phase, multistructure, and chemical composition of the prepared coatings. Experimental results indicate that the structure of the high-entropy alloy coating has gradually changed from a single phase to a mixture phase with increasing contents of alloys, suggesting that high entropy alloy coatings have the comprehensive corrosion resistance.

The temperature field and acoustic field models of muffler were built. The effect of temperature on muffler acoustic performance was studied by taking temperature field result as boundary condition of acoustic field. And the effect of inner construction parameters of the muffler is also analyzed. The muffler is refined by adjusting inner construction parameters, and the transmission loss is improved about 2∼3 dB. [ABSTRACT FROM AUTHOR]