Preparation and Characterization of A Semi-interpenetrating Network Alkaline Anion Exchange Membrane

Yifu Wang,Heting Wan,Dan Wang,Jilin Wang,Lulu Wang,Ruijiang Feng 한국섬유공학회 2018 Fibers and polymers Vol.19 No.1

A series of semi-interpenetrating network (semi-IPN) anion exchange membranes (QCS/St-G8-2-8, Quaternized chitosan/styrene-[maleic alkylene group diethyl bis (octyl dimethyl chloro/bromide), abbreviated as G8-2-8] were prepared via in-situ polymerization by Styrene (St) and G8-2-8 in QCS casting solution. During the process of in-situ polymerization, linearblock polymers (St-G8-2-8) of Styrene and G8-2-8 was constructed, then was mixed with QCS casting solution, followed crosslinking the QCS by glutaraldehyde (GA). With the increasing content of linear block polymer, water uptake and swelling ratio of the composite membrane decreased; This kind of linear structure makes an order arrangement of quaternaryammonium groups which improves the OH− migration efficiency. At 70 oC, the M-30 composite membrane performs a high OH− conductivity of 8.20×10-2 S·cm-1, the methanol permeability is 3.23×10-6 cm-2·s-1 which is still lower than Nafion 115 of 2.42×10-6 cm-2·s-1, but M-30 shows a higher selectivity of 25.3 than Nafion 115 of 11.6. Furthermore, the membranes exhibited excellent thermal stability (≥150 oC), the tensile strength of the composite membrane is in the range of 14-25 MPa and elongation at break is in the range of 16-37 % at room temperature, as well as superior chemical stability in 1.0 M KOH solution for 250 h.

Experimental study on freezing point of saline soft clay after freeze-thaw cycling

Wang, Songhe,Wang, Qinze,Qi, Jilin,Liu, Fengyin Techno-Press 2018 Geomechanics & engineering Vol.15 No.4

The brine leakage is a tough problem in artificial freezing engineering. This paper takes the common soft clay in Wujiang District as the study object, and calcium chloride solutions with six salinity levels were considered. The 'classic' cooling curve method was employed to measure the freezing point of specimens after freeze-thaw. Results indicate that four characteristic stages can be observed including supercooling, abrupt transition, equilibrium and continual freezing, strongly dependent on the variation of unfrozen water content. Two characteristic points were found from the cooling curves, i.e., freezing point and initial crystallization temperature. A critical value for the former exists at which the increment lowers. The higher the saline content approximately linearly, lower the freezing point. In the initial five cycles, the freezing point increases and then stabilizes. Besides, the degree of supercooling was calculated and its correlations with water, salt and freeze-thaw cycles were noted. Finally, an empirical equation was proposed for the relationship of freezing point and three main factors, i.e., water content, saline content and freeze-thaw cycles. Comparison of calculated and measured data proves that it is reliable and may provide guidance for the design and numerical analysis in frozen soil engineering.

A novel modeling of settlement of foundations in permafrost regions

Wang, Songhe,Qi, Jilin,Yu, Fan,Liu, Fengyin Techno-Press 2016 Geomechanics & engineering Vol.10 No.2

Settlement of foundations in permafrost regions primarily results from three physical and mechanical processes such as thaw consolidation of permafrost layer, creep of warm frozen soils and the additional deformation of seasonal active layer induced by freeze-thaw cycling. This paper firstly establishes theoretical models for the three sources of settlement including a statistical damage model for soils which experience cyclic freeze-thaw, a large strain thaw consolidation theory incorporating a modified Richards' equation and a Drucker-Prager yield criterion, as well as a simple rheological element based creep model for frozen soils. A novel numerical method was proposed for live computation of thaw consolidation, creep and freeze-thaw cycling in corresponding domains which vary with heat budget in frozen ground. It was then numerically implemented in the FISH language on the FLAC platform and verified by freeze-thaw tests on sandy clay. Results indicate that the calculated results agree well with the measured data. Finally a model test carried out on a half embankment in laboratory was modeled.

Characterization of anorthite-based porcelain prepared by using wollastonite as a calcium source

Shumei Wang,Xiaoling Qi,Jilin Hu,Xiuying Tian 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.3

The porcelain based on anorthite (CaO • Al2O3 • 2SiO2) has been developed using wollastonite (CaO • SiO2) as a calcium source. The slip casting was applied to obtain green body with high-strength. The sintering behaviors of the green specimens were evaluated by determining linear shrinkage, water absorption, bulk density and flexural strength. It was found that the anorthite porcelain fired at 1215 o C had excellent technical properties such as water absorption: 0.00% and flexural strength: 109.5 MPa. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis results showed the high flexural strength was due to the densification of microstructures and the formation of high crystalline content in the porcelain body. In addition, thermal expansion performance and appearance quality of the final product were discussed.

Paleostress reconstructions and stress regimes in the Nanchuan region of Sichuan Basin, South China: implications for hydrocarbon exploration

Wei Ju,Jilin Wang,Huihuang Fang,Yunpeng Gong,Shanjin Zhang 한국지질과학협의회 2017 Geosciences Journal Vol.21 No.4

The Longmaxi shales are the major hydrocarbon source rocks for Sichuan Basin and adjacent regions in China. Tectonic stress field is important in controling the migration and accumulation of shale gas. In the present study, natural fractures in the Nanchuan region of Sichuan Basin were extensively studied and analyzed with the Rotational Optimization Method (ROM) to reconstruct paleostress fields and their transformation processes. The dominant strikes of natural fractures were in the NW-SE, NESW, NWW-SEE and NEE-SWW directions with high-angle oblique or vertical (70~90°) dip angles. Paleostress reconstructions indicated that the Late Yanshanian and Late Himalayan stress fields controlled the tectonics in the Nanchuan region. The orientation of the maximum principal stress (σ1) during the Late Yanshanian and Late Himalayan period was ~NW-SE and ~NE-SW trending, respectively. In addition, the majority of stress regimes during the two tectonic stages were strike-slip regimes (SS). Remote effects of the westward subduction of the paleo-Pacific plate activated the Xuefengshan tectonic zone and generated the Late Yanshanian paleostress field. Later, the change in the stress field was due to the variation of tectonic activity intensity in the Xuefengshan and Dabashan tectonic zones. The paleotectonic stress fields and their transformation processes comprehensively influenced the migration and accumulation of hydrocarbons in the Nanchuan region.

An Improved Algorithm of Speech Emotion Recognition

Shulan Xia,Jilin Wang,Ru-gang Wang,Li Zhao 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.12

The traditional K-nearest neighbor algorithm existences of the risk of miscarriage of justice, for its shortage a speech emotion recognition algorithm based on fuzzy K-nearest neighbors is proposed. By introducing the fuzzy membership concept, different characteristic parameters for the different contribution of emotion recognition are calculated, and the weighted Euclidean distance is used in speech emotion recognition. The experimental results show the effectiveness of the algorithm.

A Key Pre-distribution Scheme Based on Deployment Information

Shulan Xia,Jilin Wang,Ru-gang Wang 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.11

A scheme of grouping key distribution based on polynomial protocol is proposed and experimentally demonstrated. The grouping idea is ingeniously used in the design of key distribution. The performance is experimental demonstrated by comparing with kinds of random key pre-distribution schemes. The results show that it can not only guarantee the key connected rate but also strengthen the security performance of the network, and this scheme is very suitable for static underwater acoustic communications network.

Cross-domain Recommendation by Combining Feature Tags with Transfer Learning

Yuyu Yin,Xin Wang,Jilin zhang,Jian Wan 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.10

Most recommender systems based on collaborative filtering aim to provide recommendations for a user in one domain. But data sparsity is a major problem for collaborative filtering techniques. Recently, many scholars have proposed recommendation models to alleviate the sparsity problem by transferring rating matrix in other domains. But different domains have different rating scales (e.g., rating scale may be 1-5 or 1-10). Simple process for the rating scale does not reflect the real situation. The diversity of rating scales may cause the opposite effect, making the recommendation results more imprecise. In this paper, we propose a transfer model which learning the common feature tags from other domain. This model ignores the difference of rating scales between two domains, and focus on studying the feature tags. Using its own rating values to fill the missing value. We first get the different types of users (items) based on non-negative matrix tri-factorization from auxiliary domain. The process we call the user (item) clustering. Than we can get a BP neural network which can judge the type of user according to user's feature tags by studying the features of different types of users (items). And we classify the user (items) which from target domain by exploiting the trained neural network and the users’ feature tags of target domain. Use the average rating values of the same type of users (items) to fill the missing value of target domain. We perform extensive experiments to show that our proposed model outperforms the state-of-the-art CF methods for the cross-domain recommendation task.

Power and QoS Aware Multi-level Resource Coordination and Scheduling in Virtualized Servers

Congfeng Jiang,Jingling Mao,Dongyang Ou,Yumei Wang,Xindong You,Jilin Zhang,Jian Wan 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.11

Modern cloud data centers are virtualized for resource multiplexing and services consolidations. Virtual machines (VMs) residing in the same server cluster share the same hardware resources and power supply while they may have different QoS requirements for their services and applications. Moreover, the power consumption of the server cluster is highly dynamic since different virtual machines have different workloads due to different services requests. Cluster level power and QoS coordination is crucial for data center level energy efficiency coordination as well as high quality service provisioning. In this paper we propose the power and QoS aware multi-level resource coordination and scheduling in virtualized servers, i.e., the cluster-level power control layer, the VMs resource allocation layer, and the QoS optimization layer. This three-level controlling framework schedules and allocates hardware resource for QoS guarantee and cluster level power management. We use dynamic frequency scaling for QoS mitigating when power budget changes. The experiment results show that the proposed multi-level coordinated control architecture consumes 5.36% and 6.96% less power for web servers and computing intensive virtual machines, respectively while it can guarantee the response time of web server and execution time of computing tasks no more than those without the proposed controlling approach.

Characteristics of a Large-Scale Deep Foundation Pit Excavated by the Central-Island Technique in Chengdu Soft Clay

Dongxing Ren,Chao Kang,Huanhuan Liu,Yin Li,Jilin Wang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.6

A large-scale foundation pit, 25,720 m2 (127 m × 213 m), was excavated to a depth of approximately 20 m by the central-island technique from 2012 to 2013 in Chengdu, China. This paper aims to comprehensively study the deformation behaviours of the foundation pit during excavation and investigate the primary factors affecting the deformation behaviour of the foundation pit. The deformation characteristics monitored during excavation included 1) horizontal column movement, 2) vertical column movement, 3) lateral column deflection, 4) internal stress in the column, 5) axial force in anchor cables, 6) ground settlement, and 7) artesian water levels. To further explore the pit sizes on the excavation behaviour, field data from another ten excavations in Chengdu were also included in the analysis. The results showed the maximum deflection of the column was mostly detected at the top of the column. The vertical column movement, δcu, undulates during excavation. After the desired depth was reached, the increase in the vertical column movement was negligible. The internal force in the anchor cable varied between 20 − 30 kN during the excavation and between 30 − 70 kN when the expected depth was excavated. A relatively small ground settlement in the studied excavation sites was observed due to the mudstone at the bottom of the excavation and the installation of anchor cables. In addition, it was noticed that the aspect ratio and excavation depth have a significant effect on the maximum deflection at the top of the column. This paper enriches the database and improves the understanding of the deformation behaviour of large-scale foundation pits during excavation.