Search

In Guizhou Province, there are many coal-bearing structural units, many layers of coal, thin thickness, and most of them are low permeability reservoirs, so it is advisable to adopt the process of “staged fracturing and combined layer drainage and production” to develop coalbed methane. Taking Banguan syncline coalbed methane well as an example, this study analyzed the fracturing effect of two vertical Wells on the basis of the scale of fracturing reconstruction, and then studied the influence of fracturing reconstruction effect on the gas and water production of coalbed methane Wells, and finally summarized the reasonable threshold of efficient fracturing construction parameters of Banguan syncline coalbed methane Wells. The results show that hydraulic fracturing is an effective way to increase permeability of low permeability reservoir, and the permeability increase multiple is closely related to the scale of fracturing reconstruction. The differences of sand addition, liquid addition and single-hole displacement per meter of coal seam between the two Wells of Banguan syncline lead to the permeability ratio of 55∶1 after fracturing reconstruction, and the permeability difference after reconstruction is large. Increasing the liquid addition, sand addition and single hole displacement per meter of coal seam is beneficial to improving the transformation effect of coal seam and gas production. It is recommended that the liquid addition per meter of coal seam should not be less than 400 m3, the sand addition per meter of coal seam should not be less than 20 m3, the fracturing construction displacement should not be less than 8 m3/min, and the single hole displacement should be controlled above 0.2 m3/min. According to the permeability of the coal seam after fracturing and reconstruction, it can be appropriate to quickly discharge and depressurize the coalbed methane Wells with good reconstruction effect. Otherwise, the intensity of discharge and production should be controlled to reduce the sensitivity damage of the reservoir caused by fast discharge and depressurization. The research results can provide technical reference for the permeability and energy improvement of low permeability coal seam in this block.

Aiming at the frost heave characteristics of long-distance and large-section underground freezing projects in cities, the double-line tunnel of Shanghai Metro Line 18 undercrossing an operation station was select as an example,a three-dimensional numerical model was established by using finite element software based on the thermal-mechanical coupling equation. Combined with the physical parameters obtained from laboratory tests, the evolution law of frost heave displacement field of the project was studied, and the influence of measures such as the staggered peak freezing and the adjustment of brine temperature on the frost heave displacement field was explored. Under the experimental conditions, the results show that: ① the deformation of the station floor caused by frost heave which mainly occurs in the active freezing period. When the double-line tunnel is frozen at the same time, the vertical displacement of the station floor at 45days of freezing reaches 77.72% of the displacement at 90 days of freezing. ② When the freezing time reaches 90 days, compared with simultaneous freezing, the displacement of the station floor reduced by 7.7% under the condtion of staggered peak freezing. The superposition effect of frost heave in the same time period is effectively avoided, and the frost heave effect is reduced to a certain extent. ③ When the freezing time reaches 90 days, compared with simultaneous freezing, the displacement of the station floor reduced by 34.2% under the condtion of adjusting the brine temperature, it shown that the expansion rate and frost heave effect of frozen soil are effectively controlled. In engineering practice, measures such as staggered freezing and adjusting brine temperature are used together to control frost heave, and the maximum vertical deformation of the station floor is 25.41 mm. The deformation law of the station floor obtained by numerical simulation is basically consistent with the measured data, which effectively guided the construction of the project.

Purposes Owing to the varietry of electrical equipment and the complex connection between them in transformer station, there are many common problems includeng relatively limited location and picture contrast of equipment, insufficient target images and markers in practical applications, and inaccurate electrical equipment image segmentation brought by the traditional way. In this paper, CNN (Convolutional Neural Network) is combined with Transformer to form a new model for segmentation of electrical equipment, and a new SE-Transfomer (Substation Equipment Transformer) network based on codec structure is proposed. Methods To obtain the local context information, the coder extracts the spatial feature map by using CNN at first. Meanwhile, the feature map is carefully modified with multi-scale feature inputs for global feature modeling. The decoder extracts global deep features using Transformer and performs stepwise up-sampling to predict the detailed segmentation map. SE-Transfomer is extensively experimented on the dataset of Liangjiazhuang Transformer Station in Shanxi province, and its longitudinal results of Dice, Recall, Specificity, and RMSE (Root Mean Square Error) are 89.31%, 90.52%, 89.62%, and 11.32, respectively. Findings The results indicate that SE-Transfomer obtains comparable or higher results than previous state-of-the-art segmentation methods on the scanning of electrical equipment in the transformer station.

The paper comprehensively summarizes the process of China's coal mine construction technology from introduction and absorption to independent development since the founding of New China more than 70 years ago, as well as the important achievements in basic research, process innovation, technological breakthrough, equipment development and achievement transformation, involving drilling and blasting method, freezing method, grouting method, drilling method, caisson method and other drilling technology as well as coal mine rock tunneling technology. At present, the mechanization and automation level of drilling and blasting equipment mainly for drilling and blasting rock has been significantly improved, and the comprehensive drilling technology for short-segment excavation of kilometer-level deep wells has been mature, and the maximum depth of vertical shaft drilling has reached 1341.6 m.The level of geological support technology for drilling and tunneling such as freezing method and grouting method has been significantly improved, gradually replacing the curtain method, sheet pile method and dewatering method and other drilling technology. The maximum frozen depth of vertical shaft is 990 m, and the maximum frozen section of inclined shaft is 681 m. The longest inclined shaft of 5875 m is built by working face grouting, and the ground pre-grouting reinforcement depth is 1355 m.Breakthroughs have been made in the technology of mechanical rock breaking and tunneling. The maximum drilling diameter of reverse drilling rig is 6 m, and the maximum drilling depth is 562 m.The maximum drilling diameter of vertical drilling rig is 10.8 m, and the maximum drilling depth is 660 m, and the application range is gradually expanded. The drilling method of vertical tunneling machine has achieved a breakthrough of zero, which has laid a foundation for intelligent drilling of coal mine vertical shaft. The operation line of the mechanized excavation method of the rock tunnel has been formed, and the average tunneling speed of the full section tunneling machine is more than 400 m/month. In summary, the innovation and development of coal in China mine construction technology and equipment in the past 70 years has significantly improved the operation environment, construction efficiency and safety level of the coal mine tunneling, realized the unmanned and fully mechanized operation of the tunneling working face, solved the problems of the tunnel construction in each stage of coal development in China, and ensured the basic construction and mining continuous construction of coal mines. At the same time, the technical equipment developed from the coal mine construction and the successful experience have been promoted and practiced in the underground engineering fields such as hydraulic power generation, municipal rail transit, mountain traffic tunnels, water diversion tunnels, and made contributions to the construction of national key projects and the development of national economy.

A multiplex real-time polymerase chain reaction (PCR) method for simultaneous and rapid detection of components derived from sweet potato, cassava, potato, and corn was established. The g3pdhs gene of sweet potato and cassava, the UGPase gene of potato and the zSSIIb gene of corn were used as target genes to design specific primers and TaqMan probe, and the 18S rRNA gene was used as the internal reference gene. Methodological validation was performed, and the proposed method was applied to simulated samples with different mixing ratios and actual starch samples. The results showed that this method was high-throughput, sensitive and specific. No cross-reaction was found with 15 non-target sources. The detection sensitivity for template DNA was 3 × 10-3 ng/μL, and the proposed method had a good linear relationship and high amplification efficiency. The detection limit for edible starch samples was 0.1%. The results of the PCR method for 50 actual samples were consistent with those of the reference method, indicating that this method could be used for the detection of common adulterants in edible starches.

为提高虾青素的生物利用度，增加其稳定性，采用均质乳化-探头超声法制备虾青素纳米脂质载体（AST-NLC）。以粒径和包封率为指标，通过单因素试验和中心复合设计法优化AST-NLC的制备工艺，并对制备的AST-NLC进行X射线衍射（XRD）和傅里叶红外光谱（FT-IR）结构表征，以及4、25、50 ℃下的热稳定性测试。结果表明:制备AST-NLC的最佳工艺条件为甘油三硬脂酸酯与中链甘油三酯质量比1∶ 11（总质量0.99 g）、乳化剂用量（吐温-80+大豆卵磷脂，质量比1∶ 1）3.8%（以水相质量为基准）、油水比1∶ 34（体积比）、均质速度5 000 r/min、超声时间2 min、虾青素添加量2.0 mg，在此条件下制备的AST- NLC粒径为（79.30±1.21）nm，多分散系数（PDI）为0.01±0.01，包封率为（81.36±1.84）%，Zeta电位为（-18.13±2.83）mV；结构表征结果表明，AST-NLC中的虾青素是以分子的状态包裹在脂质体中；热稳定性结果显示，4 ℃更有利于AST-NLC的保存。综上，成功制备了粒径小、分散均匀且包封率较高的AST-NLC。In order to improve the bioavailability and increase the stability of astaxanthin, astaxanthin nanolipid carrier (AST-NLC) was prepared by the homogeneous emulsification-probe ultrasonic method. The preparation process of AST-NLC was optimized by single factor experiment and central composite design method with particle size and encapsulation rate as indexes, and the AST-NLC prepared was structurally characterized by X-ray diffraction (XRD) and Fourier infrared spectroscopy(FT-IR) and tested for thermal stability at 4, 25 ℃ and 50 ℃. The results showed that the optimal process conditions for preparing AST-NLC were mass ratio of glycerol tristearate to medium chain triglyceride 1∶ 11 (total mass 0.99 g), emulsifier dosage (Tween-80+soybean lecithin, mass ratio 1∶ 1)3.8%(based on water phase mass), oil-water volume ratio 1∶ 34, homogeneous speed 5 000 r/min, ultrasonic time 2 min, astaxanthin dosage 2.0 mg. Under the optimal conditions, the AST-NLC was prepared with a particle size of (79.30±1.21) nm, a polymer dispersity index(PDI) of 0.01±0.01, an encapsulation rate of (81.36±1.84)%, and Zeta potential（-18.13±2.83）mV. The structural analysis revealed that astaxanthin in AST-NLC was encapsulated in liposomes in the state of molecules. The thermal stability results showed 4 ℃ was more favorable for the preservation of AST-NLC. In conclusion, AST-NLC with small particle size, homogenous dispersion and high encapsulation rate was successfully prepared.

Objective To analyze the basic characteristics of whole blood donors from blood stations before and after the outbreak of COVID-19. Methods After excluding invalid data, data related to the basic characteristics of whole blood donors collected from 26 blood stations in China during 2018 to 2021 were statistically analyzed, including the trend of total whole blood donors, the number of repeated blood donors, the frequency of blood donation, the average age of donors and the recruitment of first-time blood donors. Results Affected by the epidemic, 8 out of 14 indicators were with large variations, accounting for 57%. The overall growth rate of total whole blood donors during the epidemic was higher than before the epidemic (P

In order to explore the influence of dressing process parameters, such as dressing depth ad, axial feed speed fd and dressing speed ratio qd, on the grinding surface integrity of 18CrNiMo7-6 gear steel, orthogonal experiments were conducted for shaping dressing process using ceramic bonded chrome corundum grinding wheels with resin bonded diamond disc wheels, bronze bonded diamond disc wheels and single particle diamond pens, respectively. The cross grinding test of 18CrNiMo7-6 gear steel was carried out with a chrome corundum wheel after dressing. The results show that the surface roughness Ra of the grinding process increased with the increase of the dressing process parameters, and residual compressive stresses were more easily obtained on the grinding surface. The comprehensive evaluation of the grinding surface integrity for the three dressing tools, using a normalized dimensionless method, shows that the grinding surface integrity of the bronze-bonded diamond disc wheel dressing is better than the other two dressing methods. Furthermore, the grinding surface integrity is better when ad=4 μm, fd=100 mm/min, and qd=0.3.

In order to understand the main occupational disease hazards of coal mines in Huaibei City, from 2019 to 2020, all 16 coal mines in Huaibei City were selected by cluster random sampling to investigate the respiratory dust and noise of main posts, and the incidence of occupational diseases was investigated. The results show that the main occupational hazards in Huaibei coal mines are still dust and noise. The over standard rate of dust blowing posts is 51.88%, and the over standard rate of noise posts is 34.7%. The concentration of respirable dust exposed by coal miners is higher than that of tunnellers and auxiliary workers, and the exposure noise intensity of tunnellers is higher than that of coal miners and auxiliary workers. The occupational health examination for coal miners was carried out well, but the physical examination rate of noise exposed workers (34.49%) was low; the new pneumoconiosis patients are coal miners, tunnellers, etc. The length of exposure to dust and the onset latency of new pneumoconiosis patients in different types of work are different. The control of dust and noise hazards in coal mining and tunneling posts should be further strengthened.

Efficient removal of dissolved organic matter (DOM) is an important task for wastewater treatment. However, the molecular composition of DOM and its transformation during the treatment are still unclear. In this paper, the organic components in the stream of a coal coking wastewater treatment process were studied. The wastewater was extracted by dichloromethane (CH2Cl2)，the extract was named as ‘oil phase’. Then the raffinate was extracted by solid-phase extraction, the extract was named as ‘water phase’. The ratios of total organic carbon contents (TOC) in the oil and water phase samples were generally consistent during the treatment process. The extracted DOM was characterized by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Eight class species were as assigned from the mass spectra, namely N1O1-7, N2O1-6, N1O5, N1O2-6S1, N2O3-5S1, O2-8, O2-6S1, O4-5S2. The class categories which contain multiple oxygen atoms (Ox) and both multiple oxygen and sulfur atoms (OxSy) were dominant in the oil phase. The relative abundance of each species was decreased sharply after the first aerobic biological process, which was consistent with the TOC rapid decline in the sample. O2-8 compounds existed in all wastewater samples and dominated in the final sample, indicating that these compounds were the most stubborn pollutants which were difficult to remove in all treatment processes. It is speculated that these compounds may come from some humic-acids which have complex structure and multiple oxygen atoms naturally existing in natural water. The composition of O3 class species showed two patterns among the wastewater treatment process, compounds with high double bond equivalent (DBE) were dominant in the first four processes, while a proliferation of low DBE components was observed in the last three samples. It indicated that those low DBE components were generated by the oxidation of other substances, such as O1 and O2 species. The water phase organic matter had an extremely complex molecular composition and a total of 27 different compound class species were identified in a single mass spectrum. Ox, OxS1-2 and NxOyS1-2 were the major class categories in water phase. On the whole, OxS1-2 was much easier than the other two categories to be removed during the wastewater treatment process. In the OxS1-2 class category, O4S1 had a much higher relative abundance than other species. It decreased sharply among the process, but it still accounted for a large proportion in the final process, which implied the O4S1 species had strong resistance to removal. The relative abundances of each species in NxOyS1-2 had consistent composition and transformation, and could be effectively removed after the wastewater treatment process. The composition transformation trend of O6S1 was similar to N1O6S1, those compounds with low DBE value (512) and low carbon number (1020) were dominated after the aerobic biological process section and remained in the final process. The study of DOM in coal coking wastewater treatment from the molecular level by FT-ICR MS will contribute to understand the transformation law of pollutant compounds. However, limited by the mass spectrometry, only the molecular composition information can be obtained. The molecular structure information, especially for the functional groups, is hard to be obtained. In order to research the transformations law of pollutant compounds for further, the structural information needs to be deduced combining the molecular composition, the precursor and the polarity of wastewater pollutants. Developing more efficient and advanced separation and enrichment methods is another way to research the molecular structure information. By the further work, a fully understand of the pollutant composition will be obtained, and a more effective wastewater treatment process will be developed.

A multiplex real-time polymerase chain reaction (PCR) method for simultaneous rapid detection of donkey-, horse-, pig- and duck-derived components was established. For this purpose, the Nad5, ATpase6, ATP8 and cytb were used as target genes to design specific primers and Taqman probes, and the 18S rRNA gene was used as internal reference gene. The developed method was validated and applied to detect simulated adulterated meat products, simulated processed meat products and actual donkey meat samples. This method was characterized by high-throughput, and excellent sensitivity and specificity. The system had no cross-reaction to non-target sources when the cycle threshold (Ct) value did not exceed 35.0. The sensitivity was 2 × 10-4 ng/μL of template DNA. The detection limit for raw and cooked meat was 0.001% and 0.01% of the meat content, respectively. The results of this method for 100 actual samples were consistent with those of the national standard method, indicating that the multiplex real-time PCR method can be used for the detection of commonly adulterants in meat and meat products.

[Objective] The effects of forest types on soil carbon and nitrogen contents and enzyme activity were analyzed in order to provide a scientific basis for the selection of tree species and forest management methods in the transformation of subtropical coniferous forests. [Methods] The study evaluated data from a subtropical evergreen broad-leaved forest (Castanopsis carlesii forest), an evergreen deciduous broad-leaved mixed forest (Betula fujianensis and Phoebe bournei mixed forest), and a coniferous forest (Pinus massoniana forest) at the same altitude and similar environmental conditions. [Results] ① The total soil organic carbon content in the P. massoniana forest was significantly greater than in the other two forest types, and the total soil nitrogen content was not significantly different from that in the B. fujianensis and P. bournei mixed forest. However, both carbon and nitrogen contents were significantly greater than in the C. carlesii forest. The soil nitrogen and carbon reserves of the P. massoniana forest and the B. fujianensis and P. bournei mixed forest were significantly greater than the nitrogen and carbon reserves of the C. carlesii forest. The soil soluble organic carbon contents in the P. massoniana forest and the B. fujianensis and P. bournei mixed forest were significantly greater than in the C. carlesii forest. The soil soluble organic nitrogen content in the P. massoniana forest was significantly less than in the C. carlesii forest and the B. fujianensis and P. bournei mixed forest. The soil microbial biomass carbon and nitrogen contents in the C. carlesii forest and the P. massoniana forest were significantly greater than in the B. fujianensis and P. bournei mixed forest. There were no significant differences in the soil ammonium nitrogen contents among the three forest stands. However, the soil nitrate nitrogen content in the B. fujianensis and P. bournei mixed forest was significantly greater than in the other two forest types. ② The soil urease activity in the C. carlesii forest was significantly greater than in the B. fujianensis and P. bournei mixed forest. There were significant differences in soil invertase activities among the three stands, and the differences in activity followed the order of P. massoniana forest > C. carlesii forest > B. fujianensis and P. bournei mixed forest. The soil catalase activities in the P. massoniana forest and the C. carlesii forest were significantly greater than in the B. fujianensis and P. bournei mixed forest. There was no significant difference in soil phosphatase activity among the three forest stands. Soil β-glucosidase activity in the P. massoniana forest was significantly greater than in the C. carlesii forest and the B. fujianensis and P. bournei mixed forest. RDA analysis showed that the main factors affecting the change of soil enzyme activity in the three forests were total soil carbon (explanation rate of 59.5%), total nitrogen (explanation rate of 11.0%), and nitrate nitrogen (explanation rate of 14.6%). [Conclusion] The P. massoniana forest and the B. fujianensis and P. bournei mixed forest had greater soil carbon and nitrogen storage values than observed for the C. carlesii forest under the same disturbance background. The increased soil organic matter was conducive to increase soil enzyme activity.

Objective: To investigate the value of dual-source CT dual-energy virtual plain scan in the preoperative diagnosis of extramural vascular invasion (EMVI) in rectal cancer. Methods: A total of 150 patients with rectal cancer (64 females (42.7%) and 86 males (57.3%), with an average age of (62.3±11.8) years) who were scheduled for surgical treatment in our hospital from November 2019 to December 2021 were selected for the preoperative dual-source CT dual-energy virtual plain scan;. Two senior radiologists independently analyzed preoperative imaging data (including ctEMVI status, local lymph node infiltration, and distant metastasis) to determine the existence of preoperative EMVI. With pathological results as the gold standard, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of VNC in the diagnosis of EMVI were evaluated, and the area under the receiver operating characteristic curve (ROC) was used to evaluate the diagnostic efficiency. Results: Among 150 patients with rectal cancer, 56 (37.3%) were positive for EMVI and 94 (62.7%) were negative for EMVI. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of EMVI evaluation by physician 1 were 86%, 80.36%, 89.36%, 81.82%, and 88.42%, respectively, and the AUC was 0.831 (95%CI, 0.756~0.905). The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of physician 2 were 88.67%, 80.36%, 93.62%, 88.24%, and 88.89%, respectively, and the AUC was 0.870 (95%CI, 0.802~0.938). The consistency of the evaluation results between physician 1 and physician 2 was high (k=0.943). Conclusion: Dual-source CT dual-energy virtual plain scan has a certain diagnostic value in the preoperative evaluation of EMVI of rectal cancer.

Based on the structure, working principle, and working conditions of conductance water cut sensor, it is revealed that the early failure of the metal electrode of the sensor is due to the comprehensive influence of well fluid erosion, electrochemical corrosion, and oil pollution during its long-term service in the downhole. A technology for electrode surface treatment is proposed using boron-doped diamond (BDD) films to improve the service performance of the modified electrode. The hot wire chemical vapor deposition method was adopted to fabricate BDD film, the boron doping concentration and deposition time were optimized, and fluorination treatment was applied to improve the wear resistance, electrochemical corrosion resistance, and oleophobic property of the BDD film comprehensively. The results showed that BDD film with boron doping concentration of 6×10-3 exhibited high wear resistance and good electrochemical corrosion resistance, and endowed the modified electrode with superior erosion resistance and corrosion resistance. The friction coefficient and wear rate of BDD modified electrode were 92% and 78% lower than those of Invar alloy, also, the low-frequency impedance modulus value of the modified electrode was higher than 1×104 Ω·cm2. The BDD film prepared with a deposition time of 8 h had a favorable micro-nano structure owing to small grain size and uniform distribution. Such morphology was conducive to enhancing the oleophobic performance of the modified electrode, and its contact angle in the simulated well fluid was high to 102°. The engineering applicability of BDD film modified electrode under simulated working conditions indicated that, the modified electrode had excellent comprehensive performances of erosion resistance, electrochemical corrosion resistance and oil adhesion resistance, and can realize the long-term stable operation of the conductance water cut sensor under harsh downhole conditions.

To improve the adverse effects of corn starch on the color presentation of paprika red in prepared meat products, the characteristics of the effects of different concentrations of corn starch, pectin and paprika red on the color of the system were studied. The uniform design was used to optimize the concentration of the three components, and the partial least squares quadratic polynomial was used for data regression analysis. The predictive model was established that taking concentration of corn starch, pectin and paprika red as independent variables, L*, a*, b*, h, ΔE and the scattering rate as dependent variable. Results showed that, the prediction model had high accuracy, the ratio of corn starch, pectin and paprika red at best color of system, was the combination of various factors: Corn starch concentration 5.37%, pectin concentration 2.90%, paprika concentration 0.27%. At this time, the total color difference and scattering rate were: L* 49.6024, a* 39.7159, b* 40.0236, h 44.6671, ΔE 10.3461, scattering rate 0.2063. The optimal color conditions were verified to be effective in improving the color of corn starch-paprika red system in prepared meat products. In this paper, the ratio of corn starch, pectin and paprika red at best color of system obtained by the prediction model could effectively improve the color of corn starch-paprika red system.

In order to explore the influence of the grinding process parameters on the surface roughness and surface layer residual stress of 18CrNiMo7–6 steel, the cylindrical longitudinal grinding experiment was carried out by using an end cylindrical grinder. With using the workpiece speed nw, grinding depth ap and longitudinal feed speed vf, the single-factor experimental research is carried out. The research results show that with the increase of nw, the surface roughness Ra of the workpiece decreases first and then increases. When nw is 120 r/min, the surface roughness Ra reaches the minimum value, and the surface residual compressive stress value is the largest at this condition, and when nw is greater than 120 r/min, the surface residual stress exists fluctuation. With the increase of ap, the surface roughness Ra of the workpiece decreases first and then increases, and the tensile stress influence on the surface layer of the workpiece increases with the increase of the grinding depth. The surface roughness Ra first decreases and then increases with the increase of vf. When vf is 210 mm/min, the surface roughness value Ra is the smallest. With the increase of vf, the residual compressive stress of the surface layer gradually decreases and gradually changes to increasing residual tensile stress.

As the main energy source in our country, coal plays an important role in the development of the national economy. In order to facilitate industrial operation, it is necessary to reduce the temperature of coal with high ash melting point. The cement with a lower melting point was selected, and three high-melting coals (Datong, Zhundong, and Changping) were added according to a certain ratio to explore the effect of the cement on the ash melting characteristics of the high-ash-melting coal. The results show that the mortar can reduce the ash melting point of the three high-melting coals, but the degree of reduction in the melting temperature of the three coal ash is not linearly related to the content of the mortar. The effect of mortar on reducing the melting temperature of three kinds of coal ash is presented: Datong> Zhundong> Changping; the lower ash melting point of mortar is mainly due to the high content of alkaline oxides in the mortar and low content of acidic oxides, which are easy to combine with oxygen. On the contrary, alkali The ion potential of the sex ions is low, which reduces the aggregation of polymers, thereby lowering the ash melting point.

The pH value of plaeofluid exerts great influence on the formation of the secondary pores of sandstones.In the paper, the control of the acid and alkaline diagenetic fluid environment on the reservoir quality was analyzed in the Upper Paleozoic tight sandstones in the Ordos basin.Based on the plenty of survey of casting thin section, scanning electron microscope, X-ray diffraction, routine testing of physical properties, and high pressure mercury injection, the characteristics of petrology and mineralogy, physical properties, diagenesis, genetic types of pores, and pore-throat structure within the Upper Paleozoic tight sandstones were detailedly investigated in the Linxing and Shenfu district, eastern Ordos Basin.The identification, zonage, and distribution of the acid and alkaline diagenetic environment within tight sandstones as well as the evolution of diagenetic fluid environment and its reponse of the physical properties were investigated.Results showed that the upper strata underwent a diagenetic fluid evolution of alkaline-acid-alkaline mode during the burial process, whereas the lower strata experienced a mode of acid-alkaline.Acid diagenetic environment was characterized by feldspar dissolution, quartz overgrowth, and deposition of authigenic kaolinite, in which feldspar dissolution pores, intercrystalline pores of clay minerals developed with relatively large pore radius and better reservoir quality.Alkaline diagenetic environment was featured by quartz dissolution and deposition of authigenic chlorite, in which quartz dissolution pores and intercrystalline pores of clay minerals developed with relatively small pore radius and poor reservoir quality.The case of transitional zone of acid and alkaline zone(TZAA) falls in between acid zone(AZ) and alkaline zone(AlZ).Nevertheless, the physical properties are best in the AZ, followed by TZAA.The distribution of the AZ, AIZ and TAZZ and their responds to the physical properties are significant to the reservoir evaluation.

This paper introduces the United Nations standby partnership （SBP），focuses on the SPB’s launch condition and selection mechanism of the United Nations World Health Organization，analysis the United Nations SPB operation mechanism，which contains the daily management，expert roster，cooperation areas，personnel training and fund guarantee mechanism. This study will provide a theoretical basis for China to promote the cooperation with United Nations agencies in SBP.

In order to accurately apply the side-lobe echo for the severe hail warning, statistical analysis was performed on 159 samples of side-lobe echo in 9 storm supercells from 5 severe hail events in Northwest Hunan area. The radar product image characteristics of side-lobe echo were summarized systematically and the influence of side-lobe echo on observation was discussed. The distribution characteristics of side-lobe echo with intensity and space were studied in depth. The results show that:(1) For producing side-lobe echo, the minimum reflectivity factor intensity of storm core is 60 dBz. And its intensity is the decisive factor. The stronger the storm core is, the more easily side-lobe echo is generated and the more obvious feature is. The area of side-lobe echo is proportional to the area and intensity of storm core above 60 dBz. The correlation coefficients between side-lobe echo center intensity and the corresponding storm core maximum intensity, and between maximum intensity and the corresponding storm core maximum intensity can reach 0.86 and 0.92, respectively. (2) Side-lobe echo occurs the most in the following cases:about 4 km in height, 3.4° elevation, about 75 km in distance. The vertical distribution characteristic of storm nucleus echo intensity is the main factor affecting the distribution feature. (3) The frequency of the side-lobe echo occurs the most in the azimuth range of 270°-360° with obvious azimuth distribution, and the origin and path of severe storm cells determine the azimuth distribution of the side-lobe echo. (4) The side-lobe echo is distributed on one side with large echo gradient in the tangential direction of the storm. The other side exists true echo, which causes the feature of the side-lobe echo to be masked by the true echo. (5) Side-lobe echo characteristics can be regarded as a sufficient condition for severe hail warning using S-Band weather radar.

Using daily precipitation model data produced by the second version of Climate Forecasting System of NCEP (CFSv2),the ensemble prediction method is used to carry out regional summer precipitation forecast. Three methods,i.e.,the root mean square error(RMSE) and accuracy(ACCU) of the onset and the ending time of Meiyu,the RMSE of the length of Meiyu,and anomaly sign consistency rate (Pc) of the average rainfall amount of Meiyu,are used to evaluate the forecast ability of the model to the Meiyu characteristics in Hubei province. The results show that the onset of Meiyu forecast is 13 days in advance,the ACCU is above 0.5,and the RMSE is less than 3 days. The ending of Meiyu forecast is 14 days in advance,the ACCU is above 0.5,and the RMSE is less than 3 days. The length of Meiyu period forecast is 14 days in advance,and the RMSE is less than 5 days. The average rainfall amount of Meiyu forecast is 14 days in advance,and the Pc is above 0.5. In general,the aging time of Meiyu characteristics forecast is about 14 days. The CFSv2 model shows certain forecast skill for regional summer precipitation during the Meiyu extended-range period.

Objective A retrospective analysis of the clinical and pathological features of an anaplastic large cell lymphoma (ALCL) with cavernous sinus syndrome as its first symptom. Methods and Results A 35-year-old woman had head and facial pain for a month, diplopia for 7 d, right eyelid drooped for 4 d. Head MRI showed abnormal signals in right cavernous sinus, and pituitary adenoma or carvernous sinus syndrome were considered. Partial tumor resection was performed after hormone therapy was failed. Histological manifestations revealed that the tumor cells were diffuse and heterogeneous with abundant and pink stained cytoplasm, round, oval, irregular or kidney-shaped nuclei. Immunohistochemical staining showed that CD30 and CD56 were positive on the membrane, and epithelial membrane antigen (EMA) was positive on membrane and cytoplasm, and anaplastic lymphoma kinase (ALK) was negative. Ki-67 labeling index was 80%. Unfortunately, this patient died 3 weeks later after the operation, because of severe illness and intolerance to radiotherapy and chemotherapy. Conclusions The diagnosis of ALCL should be considered when cavernous sinus syndrome as the clinical symptom, and pathological examination should be performed if necessary. It should be differentiated from some tumors, such as undifferentiated non-keratinizing nasopharyngeal carcinoma, germinoma, plasmablastic lymphoma, malignant melanoma and Hodgkin's lymphoma (HL). DOI:10.3969/j.issn.1672-6731.2019.09.014

Objective To systematically review the risk of shunt-dependent hydrocephalus after treatment of ruptured intracranial aneurysms by microsurgical clipping versus endovascular coiling. Methods A comprehensive literature search from January 1990 to September 2015 was conducted in electronic databases, such as PubMed, EMBASE/SCOPUS, Cochrane Central Register of Controlled Trials (CENTRAL), China National Knowledge Infrastructure (CNKI) and Wanfang data, for randomized controlled trials (RCTs) or observational studies. Key words were defined as hydrocephalus, shunt, clipping, coiling, surgical, endovascular, embolization, treatment, intracranial aneurysm, cerebral aneurysm, subarachnoid hemorrhage both in Chinese and English. Manual search was also conducted on several relevant journals, such as Chinese Journal of Neurosurgery, Chinese Journal of Contemporary Neurology and Neurosurgery, Chinese Journal of Cerebrovascular Diseases, and so on. Data were extracted and evaluated by two reviewers independently. Jadad Scale was used to assess the quality of RCTs. Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of nonrandomized controlled trials. RevMan 5.3 and Stata 13.1 were used for Meta-analysis. Results Eighteen observational studies were finally included, involving 15 920 patients with ruptured intracranial aneurysms, among whom 10 038 patients underwent clipping and 5882 underwent coiling. The result of Meta-analysis indicated that there was no statistical significance on the incidence of shunt-dependent hydrocephalus between clipping and coiling (OR = 0.860, 95%CI: 0.720-1.030; P = 0.110). However, the findings showed low stability as the results of fixed effects model and random effects model were different. The result of Egger's test indicated no publication bias (P = 0.795). Conclusions The frequency of shunt-dependent hydrocephalus was not significantly different between clipping and coiling. However, the conclusion still needs to be further verified by high-quality studies. DOI: 10.3969/j.issn.1672-6731.2016.02.003

Concrete samples with properties similar to the continental shale core of Well Yanke 1 in the Ordos Basin in the Shaanxi province, China, were made. The control effects of horizontal principal stress difference, the angle between perforated casing and lamina, the lamina thickness and space on hydraulic fracture propagation were modeled on a real tri-axial hydraulic fracturing experiment system, based on the design principle of four factors-three levels of orthogonal experiment. When the horizontal principal stress difference is small, the main fracture surface is parallel to the laminae strike, and the primary fractures will propagate as follows: propagate through the laminae, then deflect significantly at the surface of the laminae, continue along the laminae surface and finally change direction and propagate again through the laminae. When the horizontal principal stress difference is big, the main fracture surface is perpendicular to the laminae strike and the primary fractures will propagate as follows: run through the laminae, change their propagation direction dramatically on the laminar surface, and then run through the laminae. The smaller the difference of the horizontal principal stress, the bigger the angle of fracture deflection, and the better the fracturing result will be; the smaller the angle between perforated casing and laminae, the better the fracturing result will be; when the thickness of shale laminae is moderate, there will be more branching fractures and the fracturing result is better; tuff layers with smaller lamina thickness have better hydraulic fracturing effect. The hydraulic fracturing effect is most sensitive to horizontal principal stress difference, followed by the angle between perforated well casing and laminae. Key words: shale laminated structure, hydraulic fracturing, fracture propagation, horizontal principal stress difference, fracture strike, fracturing result

There are two kinds of displacement mechanisms and three different seepage stages during horizontal well development process with water injection energy. A reasonable injection-production working system of the basic principles and parameters are determined according to the evaluation results of horizontal well development test on the basis of understanding fundamental rules. (1) Advanced water injection energy supplement mode is proposed with the combination of injection wells and large volume water fracturing of horizontal wells. (2) Theoretical calculation chart of directional well advanced water injection and water injection intensity is established for various reservoirs. (3) The timing of advanced water injection should follow the completion of the horizontal wells. (4) Reasonable initial production of horizontal well is determined by the relationship of remaining fluid volume with row spacing, advanced injection water volume and flood front advancing velocity. (5) Reasonable production flowing pressure is slightly greater than saturation pressure before water injection does not work, when it works, the reasonable production flow pressure maintains no less than two-thirds of saturation pressure, and adjust it timely combining with dynamic production. Based on the research results, the HQ oilfield put 80 horizontal wells into production during 2013, the proportion of water-breakthrough wells reduces from 8.8% to 3.0%, the annual decrease of the average production of single horizontal well is controlled within 15%. Key words: ultra-low permeable–tight oil, horizontal well, volumetric fracturing, remained underground fluid, injection-production parameters optimization, Changqing Oilfiled

Background The difference of diagnostic accuracy of 64-slice computed tomography angiography (CTA) with 3D digital subtraction angiography (3D-DSA) in the detection of intracranial aneurysms is not clear yet. This study compares the diagnostic value of 64-slice CTA with 3D-DSA in the diagnosis of intracranial aneurysms via a Meta-analysis. Methods In this study, 64-slice, 64-row, CT, angiography, intracranial aneurysms, cerebral aneurysms, subarachnoid hemorrhage, etc. were used as key words, and searched in the electronic databases including Embase, MEDLINE, Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), and Wanfang Data, assisted by manual searching, in order to retrieve articles both in English and Chinese that reported on comparisons of 64-slice CTA and 3D-DSA in the evaluation of suspected intracranial aneurysms. Meta-disc Version 1.4 was used for the Meta-analysis, and Quality Assessment of Diagnostic Accuracy Studies (QUADAS) was applied to assess the quality of these research studies. Results Four clinical trials were selected. According to the Meta-analysis, the pooled sensitivity, specificity, diagnostic odds ratios (DOR) and summary receiver operating characteristics (SROC) area under curve (AUC) was 97% (95% CI: 0.950-0.980), 91% (95% CI: 0.860-0.950), 269.640 (95% CI: 137.250-529.720) and 0.993 respectively. Conclusion On the basis of Meta-analysis, 64-slice CTA has a high level of sensitivity and specificity for diagnoses of intracranial aneurysms and it can be used as an important examination tool in the diagnoses of intracranial aneurysms. Because the sample size of selected studies is small, it is necessary to perform well-designed and larger sample studies to further assess the diagnostic value of intracranial aneurysms by 64-slice CTA.

Objective To compare the effectiveness and safety of microendoscopic discectomy (MED) versus microscopic discectomy (MD) for treatment of lumbar disc herniations. Methods Key words were defined as microendoscopic discectomy, microscopic discectomy, lumbar disc herniation, etc. The electronic databases (PubMed, EMbase, Cochrane Central Register of Controlled Trials, CNKI, and Wanfang) were searched in order to retrieve randomized controlled trials (RCTs) about comparing MED and MD for the treatment of lumbar disc herniations. We also applied manual searching to screen out relevant journals. Data were extracted and evaluated by two reviewers independently. The quality of the included trails was evaluated by Jadad scales. Cochrane collaboration's RevMan 5.0.24 were used for data analysis. Results Four RCTs involving 1069 patients were included in the Meta⁃analysis. Results of Meta⁃analysis showed that: the Oswestry dysfunctional index (ODI) after operation in MED group was not significantly different from that in the MD group (MD = ⁃ 0.170, 95%CI: ⁃ 3.590-3.260; P = 0.920); dural tears in MED group were higher than those of MD group (RR = 3.040, 95%CI: 1.170-7.890; P = 0.020); there were no significant difference between MED group and MD group in terms of root injury (RR = 5.130, 95% CI: 0.890-29.420; P = 0.070) and recurrent herniation (RR = 2.320, 95%CI: 0.970-5.520; P = 0.060); there were significant difference between MED group and MD group in terms of surgical time (MD = 10.780, 95%CI: 7.180-14.370; P = 0.000), size of incision (MD = ⁃ 0.950, 95%CI: ⁃ 1.840-0.070; P = 0.030) and length of hospital stay (MD = 0.210, 95%CI: ⁃ 0.080-0.340; P = 0.002). There was no significant difference between MED group and MD group in terms of blood loss (MD = 27.420, 95% CI: ⁃ 8.840-63.680; P = 0.140). Conclusion According to present knowledge, the two techniques were found to be effective for the treatment of lumbar disc herniations, but recurrent herniations were significantly more common in MED group. As for the safety of the two techniques, dural tears and root injuries were significantly more common in MED group. Because of the limitation of the quality and amount for the RCTs included, the results of this systematic review should be prudently cited, and more high quality RCTs are needed to be performed. DOI：10.3969/j.issn.1672⁃6731.2012.04.006

By choosing suitable Banach spaces and constructing adequate auxiliary boundary value problems, the existence theorem of solutions to multi-point boundary value problems of p-Laplacian differential systems were proved via variational method. The proposed theorem is different from the results obtained by the Topological degree theory and the fixed-point theorems. [ABSTRACT FROM AUTHOR]

To solve near field electromagnetic scattering characteristics by complex target, finite element method (FEM) was used to calculate scattering characteristics by complex target under Hertz dipole's radiation spherical wave. Because of the limited computation domain by FEM, scattering field anywhere in space was strictly deduced by the current and magnetic sources on the output interface which encloses the target. The strict scattering field was then used to compute the generalized radar cross section in target near field. Numerical experiments demonstrate the correctness of scattering formula and the validity of this method. [ABSTRACT FROM AUTHOR]

The existence of periodic solutions for a kind of second-order functional differential equation is studied. By using the abstract continuation theorem, some sufficient conditions of periodic solutions in existence of the equation are obtained. The conditions that the nonlinear terms of the equation should be satisfied are derived and they are not the same with the conclusions appeared in the previous papers. [ABSTRACT FROM AUTHOR]

As a generalization of Fan-Glicksberg fixed point theorem, a new existence theorem of fixed point theorem for set-valued mapping is proved. And then, by introducing the concept of weakly quasiconcave function, and replacing quasiconcave function by weakly quasiconcave function, a new existence theorem of Nash equilibrium point for game theory is deduced. Lastly an example is given to prove that the new theory is more useful. [ABSTRACT FROM AUTHOR]

Using fixed point index theory in cones sufficient conditions are presented, which guarantee the existence of multiple positive solutions to a class of impulsive singular m-point boundary value problems. [ABSTRACT FROM AUTHOR]

Applying fixed point theory in cones sufficient conditions that guarantee the existence of positive solutions are presented to a class of impulsive singular eigenvalue problems. [ABSTRACT FROM AUTHOR]

In order to analyze shock wave propagation of coal and gas outburst induced by roadway cross-section variation, firstly, mathematic model of outburst shock wave propagation in variation cross-section roadway was established by fluid dynamics and air dynamics, the variation law between shock wave propagation and cross-section variation rate were obtained by theory analysis. Secondly, the experimental system for shock wave propagates in variation cross-section roadway was constructed, and the shock wave propagation law was revealed. The experimental results indicate that overpressure becomes larger and the energy per area of the wavefront is increased when shock wave propagates form large cross-section to small one. Then numerical simulation model of shock wave propagate in variation cross-section was established, the simulation results show that the greater the initial shock wave overpressure is, the faster the shock wave decay, and the larger the roadway cross-section variation rate is, the greater the shock wave attenuation coefficient is. Finally, comparative analysis shows that the theoretical analysis, experimental research and numerical results are consistent. [ABSTRACT FROM AUTHOR]

Currently, micro- and nanoplastics are the most concerning pollutants, which have been confirmed to exist in every stage of drinking water treatment process. Micro- and nanoplastics in drinking water have large specific surface areas, which could adsorb inorganic matter, organic matter, and microorganisms, thereby increasing their risk to human health. The adsorption and agglomeration behavior of micro- and nanoplastics on typical pollutants is called the "colloid pump effect." Focused on the micro- and nanoplastics in drinking water, the occurrence, colloid pump effect, and toxic effect on the human body and the effect of colloid pumps on the removal of micro- and nanoplastics were summarized and described. The results revealed that micro- and nanoplastics existed widely in source water, treated water, pipe network water, and tap water. The colloid pump effect of micro- and nanoplastics promoted their agglomeration with inorganic matter, organic matter, and microorganisms, which not only intensified the toxic effect of micro- and nanoplastics but also affected the removal effect. There were different viewpoints on the effect of coagulation and sedimentation on the removal of micro- and nanoplastics, and the removal effect of sand filters was limited. The advanced treatment was an efficient process to remove micro- and nanoplastics with a particle size smaller than 5 μm. The removal rate of micro- and nanoplastics could be effectively improved by exploring the mechanism of the colloid pump effect and its initiation conditions. Finally, from the perspective of the drinking water treatment process and colloid pump effect, the control of micro- and nanoplastics in drinking water was prospected in order to provide reference for reducing the occurrence and toxicity of micro- and nanoplastics in drinking water, ensuring drinking water quality safety and human health.

As an emerging pollutant of global concern, microplastics (plastics with size<5 mm) and heavy metals are widely found in freshwater environments. Microplastics migrate easily, are difficult to degrade, and have large specific surface areas. They can enrich a variety of pollutants such as heavy metals and greatly increase their potential harm to the environment and ecology. Firstly, the special environmental behavior of microplastics carrying heavy metals and migrating together in freshwater environments was defined as the "Trojan-horse effect." Then, the Trojan-horse effect and its mechanism of microplastics and heavy metals in the freshwater environment were summarized and expounded from four aspects:the source and distribution of microplastics in the freshwater environment, the enrichment effect of microplastics on heavy metals, the impact of microplastics and the heavy metal Trojan-horse effect on its migration behavior, and the biological impact of microplastics and the heavy metal Trojan-horse effect. The results showed that, as a wide range of non-point source pollutants, microplastics widely existed in freshwater environments. In freshwater environments, the adsorption degree of single metals was different in different environments. It was mainly affected by microplastics, metals, and environmental factors. There was competitive adsorption in the presence of multiple metal ions. The Trojan-horse effect of microplastics and heavy metals could also affect their co-transport behavior. The Trojan-horse effect of microplastics and heavy metals in the freshwater environment frequently exacerbated their toxicity to aquatic organisms. This study provides references for comprehensively understanding the Trojan-horse effect and its mechanism in microplastics and heavy metals in the freshwater environment, which could effectively reduce the ecological risk and impact on human health of microplastics and heavy metals in the freshwater environment.

The soil fertility quality is one of the most critical indicators of soil productivity. It directly affects the yield, quality and agricultural efficiency of Chinese medicinal materials. In order to establish the American ginseng planting soil fertility quality evaluation method based on the effective components of American ginseng, Wendeng district, Weihai city, Shandong province, the main producing area of American ginseng, was cited as a case for the study. Twenty-two 4-years American ginseng sampling sites are located at 7 towns. The samples of soil and plant root were collected in the autumn of 2017-2019. The saponin contents of American ginseng and 11 soil chemical properties were measured. The minimum data set(MDS) for assessment of the quality of soil fertility quality was established by correlation analysis and principal component analysis. The evaluation indexes were normalized by membership function. Soil quality index(SQI) that indicates soil comprehensive fertility quality level was calculated according to the critical value of membership function and weight value of each soil index in MDS. The results showed that the total saponin(Rg&#95;1+Re+Rb&#95;1) content of American ginseng in samples ranged from 1.76% to 7.94%. The yield of 8 plots in 2019 ranged from 3 818.7 kg·hm~(-2) to 8 996.4 kg·hm~(-2). MDS includes organic matter, alkaline nitrogen, exchangeable calcium, exchangeable magnesium, effective iron, effective copper, and effective zinc. Based on the mean of 4.825% of total saponin, threshold value of SQI for the region was determined to be 0.15, and 86.36% of soil samples in the county were above the threshold value. The methods and parameters are applicable to selection of high quality American ginseng planting sites and guiding rational fertilization. It also provides a reference for the evaluation of soil fertility quality of other medicinal plants.