An Evaluation of Ice Nuclei Characteristics from the Long-term Measurement Data over North China

Yin Jinfang,Wang Donghai,Zhai Guoqing 한국기상학회 2012 Asia-Pacific Journal of Atmospheric Sciences Vol.48 No.2

An attempt was made to delineate the characteristics of ice nuclei (IN) over North China using the ground-based measurement data from 1963-2003. The results show that: (1) the IN concentrations increased during the period from 1963-1996, but decreased after 2000; (2) the average IN concentrations range from 1.0 to 26.3,3.6 to 78.9, 19.2 to 627.3, and 92.9 to 5285.0 L−1 at temperature −15,−20, −25, and −30oC, with the overall average of 7.8, 20.6, 167.7,and 890.6 L−1, respectively; and (3) the number concentration of active IN increased nearly exponentially with decreasing temperature,with the slope (ranging from 0.11 to 0.42oC−1) being of a narrow range in a log-linear coordinate; the regression equations for the western central China and the eastern central China can be expressed as N(T) = 0.0396 exp (−0.317ΔT) and N(T) = 0.1496 exp (−0.299ΔT),respectively. The present study may be useful toward applications in models for predicting IN effects on the cloud, precipitation and climate over North China.

Characterization of the brittleness of hard rock at different temperatures using uniaxial compression tests

Chen, Guoqing,Li, Tianbin,Wang, Wei,Guo, Fan,Yin, Hongyu Techno-Press 2017 Geomechanics & engineering Vol.13 No.1

The failure mechanism of a deep hard rock tunnel under high geostress and high geothermalactivity is extremely complex. Uniaxial compression tests of granite at different temperatures were conducted. The complete stress-strain curves, mechanical parameters and macroscopic failure types of the rock were analyzed in detail. The brittleness index, which represents the possibility of a severe brittleness hazard, is proposed in this paperby comparing the peak stress and the expansion stress. The results show that the temperature range from 20 to $60^{\circ}C$ is able to aggravate the brittle failure of hard rock based on the brittleness index. The closure of internal micro cracks by thermal stress can improve the strength of hard rock and the storage capacity of elastic strain energy. The failure mode ofthe samples changes from shear failure to tensile failure as the temperature increases. In conclusion, the brittle failure mechanism of hard rock under the action of thermal coupling is revealed, and the analysis result offers significant guidance for deep buried tunnels at high temperatures and under high geostress.

Enhancement mechanism of SO2 removal with calcium hydroxide in the presence of NO2

Jihui Gao,Guoqing Chen,Xiaolin Fu,Yijun Yin,Shaohua Wu,Yukun Qin 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.2

The enhancement mechanism of SO2 removal by the presence of NO2 under low temperature and humid conditions was studied in a fixed bed reactor system. The presence of NO2 in the flue gas can enhance SO2 removal. The interaction between SO2 and NO2 in gas phase could not explain the effect of NO2 on SO2 removal under lowtemperature and humid conditions. When Ca(NO3)2 and Ca(NO2)2 as additive were added on the surface of sorbent,the desulfurization activity of sorbent decreased. However, the sorbent pretreated by NO2 for a moment has higher SO2removal. The oxidization of SO32− to SO42− and the evolution of sorbent surface structure in the presence of NO2 can explain the enhancement of SO2 removal by the presence of NO2. HSO3− and SO3− reacted with NO2 to form sulfate,which can accelerate the hydrolysis of SO2. The reaction between NO2 and Ca(OH)2 can make the unreacted sorbet under the SO2 removal product exposed to the reactant gas.

Stochastic analysis for uncertain deformation of foundations in permafrost regions

Wang, Tao,Zhou, Guoqing,Wang, Jianzhou,Zhao, Xiaodong,Yin, Leijian Techno-Press 2018 Geomechanics & engineering Vol.14 No.6

For foundations in permafrost regions, the displacement characteristics are uncertain because of the randomness of temperature characteristics and mechanical parameters, which make the structural system have an unexpected deviation and unpredictability. It will affect the safety of design and construction. In this paper, we consider the randomness of temperature characteristics and mechanical parameters. A stochastic analysis model for the uncertain displacement characteristic of foundations is presented, and the stochastic coupling program is compiled by Matrix Laboratory (MATLAB) software. The stochastic displacement fields of an embankment in a permafrost region are obtained and analyzed by Neumann stochastic finite element method (NSFEM). The results provide a new way to predict the deformation characteristics of foundations in permafrost regions, and it shows that the stochastic temperature has a different influence on the stochastic lateral displacement and vertical displacement. Construction disturbance and climate warming lead to three different stages for the mean settlement of characteristic points. For the stochastic settlement characteristic, the standard deviation increases with time, which imply that the results of conventional deterministic analysis may be far from the true value. These results can improve our understanding of the stochastic deformation fields of embankments and provide a theoretical basis for engineering reliability analysis and design in permafrost regions.

Natural fracture prediction in Keshen 2 ultra-deep tight gas reservoir based on R/S analysis, Kuqa Depression, Tarim Basin

Hui Zhang,Wei Ju,Guoqing Yin,Xinyu Liu,Zhimin Wang,Sijia Liu,Ke Wang,Hui Yang,Ke Xu,Wenbo Luan 한국지질과학협의회 2021 Geosciences Journal Vol.25 No.4

Within ultra-deep tight sandstone gas reservoirs, natural fractures indicate significant effects on reservoir performance because they can serve as storage spaces for hydrocarbons and improve the permeability. Accurate prediction of natural fractures in ultra-deep reservoirs is critical to the exploration and development of tight gas in Keshen 2 Block of Kuqa Depression. In this study, several conventional logs are selected and the R/S analysis method is introduced to predict the development and distribution of natural fractures in ultra-deep tight sandstone reservoirs. Fracture development coefficient Q is calculated based on the second derivatives of lg(R/S) function and corresponding weight of each log parameter, which matches well with linear fracture density measured from image logs. There is a positive correlation between parameter Q and fracture density, higher Q values usually indicate larger fracture density. Factors causing mismatches between calculated parameter Q and fracture density are also analyzed. Fracture dip angle, fracture filling condition, vertical resolution of logs, multiple interpretations of conventional logs, and lateral detection difference between image and conventional logs may contribute to generate those false appearances. The results in this study are expected to provide new geological references for the exploration and development of ultra-deep tight gas in Keshen 2 Block of Kuqa Depression.

Replacing alfalfa hay with amaranth hay: effects on production performance, rumen fermentation, nutrient digestibility and antioxidant ability in dairy cow

Ma Jian,Fan Xue,Sun Guoqing,Yin Fuquan,Zhou Guangxian,Zhao Zhihui,Gan Shangquan 아세아·태평양축산학회 2024 Animal Bioscience Vol.37 No.2

Objective: The aim of this research was to explore the effects of dietary substitution of alfalfa hay by amaranth hay on production performance, rumen fermentation, nutrient digestibility, serum biochemical parameters and antioxidant ability in dairy cows. Methods: A total of 45 healthy Holstein cows with same parity and similar milk yield and body weight were randomly divided into 3 groups: control diet without amaranth hay (CON) or 50% and 100% alfalfa hay replaced by an equal amount of amaranth hay (dry matter basis, AH1 and AH2, respectively). All the cows were fed regularly 3 times a day at 06:30, 14:30, and 22:30 and had free access to water. The experiment lasted for 60 d. Results: The dry matter intake of CON and AH1 groups was higher (p<0.05) than that of AH2 group. Compared with AH1 group, the milk yield of AH2 group was reduced (p<0.05). Moreover, dietary substitution of alfalfa hay by amaranth hay increased (p<0.05) milk fat, ammonia nitrogen and acetate concentrations. However, the crude protein digestibility of AH2 group was lower (p<0.05) than that of CON group, while an opposite tendency of serum urea nitrogen was found between two groups. The neutral detergent fiber digestibility of AH1 group was increased (p<0.05) when compared to AH2 group. Amaranth hay treatment increased (p<0.05) the serum concentration of glutathione peroxidase in dairy cows. Compared with CON group, the malonaldehyde activity of AH1 group was decreased (p<0.05). Conclusion: Dietary replacing alfalfa hay with amaranth hay (50% ratio) in dairy cows did not affect production performance but improved their antioxidant ability.

Comparison of the Radiation Shielding Properties of Wall Materials for the Manned Spacecraft for Future China Space Exploration Missions

Huibin Sun,Zhengxin Wu,Yugang Ma,Jinbin Lu,Guoqing Liu,Haige Zhao,Yin Wang,Yanqi Hu 한국물리학회 2019 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.75 No.9

The radiation environment in space poses signicant challenges to human health, and it is a ma- jor concern in long duration, manned space missions. Outside Earth's protective magnetosphere, astronauts are exposed to higher levels of galactic cosmic rays (GCRs), whose physical character- istics are distinct from those of terrestrial sources of radiation, such as X-rays and gamma-rays. GCRs include high-energy heavy ions, many of which have ranges that exceed the depth of shielding and can be launched in realistic scenarios. Protecting the astronauts from these particles has been a key issue in manned space missions. Therefore, a need exists for reliable simulations of these harmful effects for risk assessment and shielding optimization in manned space missions. The aim of this work was to investigate shielding materials that can be used in deep space and planetary exploration. In this work, we used the Geant4 radiation transport code, originally developed by the International Geant4 Collaboration, and we compared the radiation shielding effectivenesses of polyethylene, aluminum, water, and carbon ber targets hit by 1GeV/nucleon 56Fe (considered as a representative of high-energy GCR). In addition, the total absorbed doses at the water phantom behind these targets were calculated using the Geant4 simulation code. The calculated results were analyzed, compared, and discussed. The results show that polyethylene is the best space radiation shielding material for a given areal density, followed by water, carbon ber, and then aluminum.