Research on Quantitative Analysis for Nano-pore Structure Characteristics of Shale Based on NMR Cryoporometr

( Zhiqing Li ) 대한지질공학회 2019 대한지질공학회 학술발표회논문집 Vol.2019 No.2

Shale gas, as one kind of unconventional gas, is an important energy supplement. The pore structure characteristic is an important index using to measure and evaluate shale reservoir quality. The Weiyuan marine shale, Jiao Shiba marine shale and Yaoqu continental shalewere selected to study the pore structure characteristics and controlling factors using cold field emission scanning microscopy (FE-SEM). Nuclear magnetic resonance cryoporometry (NMRC) was employed to represent nano-scale pore structure. This method can be extended to microns measurement combining nuclear magnetic resonance relaxation analysis to detect in detail the pore structure of shales under the different aperture scales. The smaller the test temperature gradient is, the finer the result of pore distribution is.. NMRC, mercury intrusion porosimetry (MIP) and gas adsorption (GA) methods show good agreement of pore distribution in their respective scope of application. NMR method results in a much better estimate for the total pore volume than the more common MIP and GA. Hence, the pore structure of the reservoir shale can be evaluated more accurately by combining NMRC, LFNMR with GA and MIP. Thus the nano-pores of continental shale are clearly better developed and will more likely have a higher commercial exploitation value than marine shale.

Cast Iron Smelting and Fining: An Iron Smelting Site of the Eastern Han Dynasty in Xuxiebian, Sichuan Province, China

( Yuniu Li ),( Chunyan Ma ),( Yasuyuki Murakami ),( Zhiqing Zhou ),( Yingdong Yang ),( Yingfu Li ) 성균관대학교 동아시아학술원 2019 Sungkyun Journal of East Asian Studies Vol.19 No.1

In this article, we introduce the excavation of an iron smelting site at Xuxiebian 許鞋匾, Pujiang 蒲江 County, Sichuan 四川 Province in the PRC. Two excavations were carried out in 2007 and 2011, and a total of four bowl-shaped furnaces, five pits, two trenches, and one posthole were excavated. The site is dated from the mid-late Eastern Han dynasty to the Jin dynasty (ca. AD 150-420) according to the local pottery assemblage. It is possible that the sole functions of the Xuxiebian site were the production of pig iron ingots and the conversion of pig iron to wrought iron. The iron ingots were likely transported to areas with stronger administrative control by the central government near the ancient city of Chengdu or even to the Central Plains, where they were then cast into different objects.

The Asymptotic Throughput and Connectivity of Cognitive Radio Networks with Directional Transmission

Zhiqing Wei,Zhiyong Feng,Qixun Zhang,Wei Li,T. Aaron Gulliver 한국통신학회 2014 Journal of communications and networks Vol.16 No.2

Throughput scaling laws for two coexisting ad hoc networkswith m primary users (PUs) and n secondary users (SUs)randomly distributed in an unit area have been widely studied. Early work showed that the secondary network performs as wellas stand-alone networks, namely, the per-node throughput of thesecondary networks is (1/pn log n). In this paper, we showthat by exploiting directional spectrum opportunities in secondarynetwork, the throughput of secondary network can be improved. If the beamwidth of secondary transmitter (TX)’s main lobe is= o(1/log n), SUs can achieve a per-node throughput of(1/pn log n) for directional transmission and omni reception(DTOR), which is (log n) times higher than the throughputwithoutdirectional transmission. On the contrary, if = !(1/log n),the throughput gain of SUs is 2 / for DTOR compared with thethroughput without directional antennas. Similarly, we have derivedthe throughput for other cases of directional transmission. The connectivity is another critical metric to evaluate the performanceof random ad hoc networks. The relation between the numberof SUs n and the number of PUs m is assumed to be n = m . We show that with the HDP-VDP routing scheme, which is widelyemployed in the analysis of throughput scaling laws of ad hoc networks,the connectivity of a single SU can be guaranteed when> 1, and the connectivity of a single secondary path can be guaranteedwhen > 2. While circumventing routing can improve theconnectivity of cognitive radio ad hoc network, we verify that theconnectivity of a single SU as well as a single secondary path canbe guaranteed when > 1. Thus, to achieve the connectivity ofsecondary networks, the density of SUs should be (asymptotically)bigger than that of PUs.

An analytical solution for one-dimensional contaminant transport in a double-layered contaminated soil with imperfect diffusion boundaries

Xibin Li,Jianchao Sheng,Zhiqing Zhang,Zhe Wang 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.4

An analytical method is proposed to solve the contaminant transport in a double-layered contaminated soil with imperfect diffusion boundaries. By virtue of the separation of variables scheme, the governing equation for contaminant diffusion is split into two ordinary differential equations, and the corresponding general solutions are obtained. By utilizing the initial, continuity and boundary conditions of the system, and the orthogonality of trigonometric functions, the analytical solution for contaminant concentration in the double-layered contaminated soil is derived, which can be further used to describe the average degree of diffusion. The reliability and accuracy of the developed solution is verified by comparing with the existing analytical solution and numerical simulation results. Selected numerical examples are further presented to analyze the influence of the imperfect diffusion boundaries on the spatial/time distribution of contaminant concentration, average degree of diffusion and mass flux. The results show that greater imperfect diffusion capacity coefficients lead to lower contaminant concentration distribution within the entire depth range and higher average degree of diffusion for a given time. Particularly, it only takes 23.32 years to complete the entire diffusion process when imperfect diffusion capacity coefficients are infinite. The developed solution can provide useful guidance for engineering practice.

Study on Numerical Model with Multi-layer Rigid Balls for Fabricating Curved Surface Based on Clustering Balls Spinning Method

Hu Zhiqing,Li Jiaji,Yu Ge,Lin Baojun 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.8

Clustering balls spinning method is a new method for fabricating curved surfaces by clustering rigid balls. It is always one of options to explore forming mechanism by using numerical simulation method that is closer to the real experimental process. In this article, we have adopted a new numerical model with multi-layer rigid balls (MlRB), which is named as MlRB model and more responsive to actual experiments. The model subroutine is developed based on the ABAQUS software. Simulation procedure using MlRB model is introduced, and cross-section, thickness distribution and springback using MlRB model are analyzed and compared to the experimental results and simulated results using previous numerical model with single-layer rigid balls (SlRB), which is named as SlRB model. The results are shown that, curved surface and thickness distribution simulated by MlRB model are closed to experimental results, and springback of curved surface is much less. Furthermore, auxiliary forming region that benefits to make the sheet deformed furtherly is proposed and analyzed. It is indicated that MlRB model is successful to simulate the deformation of the sheet according to the experiment, and it lays the foundation for the optimization of the technology parameters in the future.

On Research IoT-based Intelligent Parking Management System and Its Design

Xu Zhiqing,He Jialianga,Li Haidong 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.5

With the rapid economic development and constant social advancement in our country, people's production and lifestyle are undergoing profound changes, consequently resulting in traffic jams and increasingly severe challenges on the limited parking resources. How to enhance the utilization of parking places has been an important problem influencing city image and the harmonious economic and social development. This paper introduces a Internet of Things (IoT)-based intelligent parking management system, innovatively proposes a non-source RFID card that utilizes label and sensor binding to actualize vehicle identification and to accomplish functions of vehicle entrance & exit authentication, automatic charging, and parking lot certification, eventually further enhancing the utilization, traffic efficiency and service level of parking places.

The Asymptotic Throughput and Connectivity of Cognitive Radio Networks with Directional Transmission

Wei, Zhiqing,Feng, Zhiyong,Zhang, Qixun,Li, Wei,Gulliver, T. Aaron The Korea Institute of Information and Commucation 2014 Journal of communications and networks Vol.16 No.2

Throughput scaling laws for two coexisting ad hoc networks with m primary users (PUs) and n secondary users (SUs) randomly distributed in an unit area have been widely studied. Early work showed that the secondary network performs as well as stand-alone networks, namely, the per-node throughput of the secondary networks is ${\Theta}(1/\sqrt{n{\log}n})$. In this paper, we show that by exploiting directional spectrum opportunities in secondary network, the throughput of secondary network can be improved. If the beamwidth of secondary transmitter (TX)'s main lobe is ${\delta}=o(1/{\log}n)$, SUs can achieve a per-node throughput of ${\Theta}(1/\sqrt{n{\log}n})$ for directional transmission and omni reception (DTOR), which is ${\Theta}({\log}n)$ times higher than the throughput with-out directional transmission. On the contrary, if ${\delta}={\omega}(1/{\log}n)$, the throughput gain of SUs is $2{\pi}/{\delta}$ for DTOR compared with the throughput without directional antennas. Similarly, we have derived the throughput for other cases of directional transmission. The connectivity is another critical metric to evaluate the performance of random ad hoc networks. The relation between the number of SUs n and the number of PUs m is assumed to be $n=m^{\beta}$. We show that with the HDP-VDP routing scheme, which is widely employed in the analysis of throughput scaling laws of ad hoc networks, the connectivity of a single SU can be guaranteed when ${\beta}$ > 1, and the connectivity of a single secondary path can be guaranteed when ${\beta}$ > 2. While circumventing routing can improve the connectivity of cognitive radio ad hoc network, we verify that the connectivity of a single SU as well as a single secondary path can be guaranteed when ${\beta}$ > 1. Thus, to achieve the connectivity of secondary networks, the density of SUs should be (asymptotically) bigger than that of PUs.

Accuracy evaluation of 3D time-domain Green function in infinite depth

Zhang Teng,Zhou Bo,Li Zhiqing,Han Xiaoshuang,Gho Wie Min 대한조선학회 2021 International Journal of Naval Architecture and Oc Vol.13 No.1

An accurate evaluation of three-dimensional (3D) Time-Domain Green Function (TDGF) in infinite water depth is essential for ship’s hydrodynamic analysis. Various numerical algorithms based on the TDGF properties are considered, including the ascending series expansion at small time parameter, the asymptotic expansion at large time parameter and the Taylor series expansion combines with ordinary differential equation for the time domain analysis. An efficient method (referred as “Present Method”) for a better accuracy evaluation of TDGF has been proposed. The numerical results generated from precise integration method and analytical solution of Shan et al. (2019) revealed that the “Present method” provides a better solution in the computational domain. The comparison of the heave hydrodynamic coefficients in solving the radiation problem of a hemisphere at zero speed between the “Present method” and the analytical solutions proposed by Hulme (1982) showed that the difference of result is small, less than 3%.

The conditional risk probability-based seawall height design method

Yang, Xing,Hu, Xiaodong,Li, Zhiqing The Society of Naval Architects of Korea 2015 International Journal of Naval Architecture and Oc Vol.7 No.6

The determination of the required seawall height is usually based on the combination of wind speed (or wave height) and still water level according to a specified return period, e.g., 50-year return period wind speed and 50-year return period still water level. In reality, the two variables are be partially correlated. This may be lead to over-design (costs) of seawall structures. The above-mentioned return period for the design of a seawall depends on economy, society and natural environment in the region. This means a specified risk level of overtopping or damage of a seawall structure is usually allowed. The aim of this paper is to present a conditional risk probability-based seawall height design method which incorporates the correlation of the two variables. For purposes of demonstration, the wind speeds and water levels collected from Jiangsu of China are analyzed. The results show this method can improve seawall height design accuracy.

The conditional risk probability-based seawall height design method

Xing Yang,Xiaodong Hu,Zhiqing Li 대한조선학회 2015 International Journal of Naval Architecture and Oc Vol.7 No.6

The determination of the required seawall height is usually based on the combination of wind speed (or wave height) and still water level according to a specified return period, e.g., 50-year return period wind speed and 50- year return period still water level. In reality, the two variables are be partially correlated. This may be lead to overdesign (costs) of seawall structures. The above-mentioned return period for the design of a seawall depends on economy, society and natural environment in the region. This means a specified risk level of overtopping or damage of a seawall structure is usually allowed. The aim of this paper is to present a conditional risk probability-based seawall height design method which incorporates the correlation of the two variables. For purposes of demonstration, the wind speeds and water levels collected from Jiangsu of China are analyzed. The results show this method can improve seawall height design accuracy.