Accelerating Dissolution of Polyacrylamide in Offshore Oil Field

Qin Yu,Xiangguo Lu,Defu Zhang,Kun Xie 대한화학회 2015 Bulletin of the Korean Chemical Society Vol.36 No.10

The solubility of polyacrylamide significantly reduces the efficiency of polymer flooding in offshore oil fields, because of the low performance of polyacrylamide and the special environment. The objective of this paper is to investigate a novel approach to accelerate the dissolution of hydrolyzed polyacrylamide (HPAM) by adding a co-solvent cholamine (MEA). We investigated the effects of MEA on the microstructure and the performance of HPAM. Results showed that the addition of MEA and the temperature rise greatly shortened the dissolution time of HPAM, while improved the rheological property and seepage behavior. The enhanced solubility of polyacrylamide and the performance of polymer solution can be attributed to the enlarging of the molecular clew size, the stretching of molecular chains and the lowering of the glass transition temperature of HPAM. The new approach has high practical and the economic values for applications of the polymer flooding technology in offshore oilfields with complex reservoir conditions.

Enhancement of grain growth and electrical conductivity of La_0.8Sr_0.2MnO₃ ceramics by microwave irradiation

Qin, Fen,Roh, Hee-Suk,Caliskan, Salim,Lee, Seongha,Kim, Sun-Dong,Woo, Sang Kook,Lee, Jung-Kun Elsevier 2019 Journal of the European Ceramic Society Vol.39 No.5

<P><B>Abstract</B></P> <P>We studied crystallization, grain growth and electric properties of La<SUB>0.8</SUB>Sr<SUB>0.2</SUB>MnO<SUB>3</SUB> (LSM) ceramics which were produced using the microwave-treatment. While co-precipitated nanoparticles remain mainly amorphous, the microwave irradiated particles are crystallized into LSM and La<SUB>2</SUB>Mn<SUB>2</SUB>O<SUB>7</SUB> at 550 °C, due to higher dielectric polarizability of La. This, in turn, decreases the amount of the second phase La<SUB>2</SUB>O<SUB>3</SUB> in calcined powder and promotes the growth of perovskite grains during sintering at 1400 °C. Larger grains of LSM ceramics lower the activation energy of small polaron hopping from 0.35 eV to 0.24 eV and increases high-temperature electric conductivity. In addition, high crystallinity of LSM ceramics from the microwave-treatment suppresses a chemical reaction with ZrO<SUB>2</SUB> and NiO in a temperature range of 900 – 1100 °C under oxidizing and reducing ambiances. These results show that LSM ceramics from the microwave-assisted reaction meet requirements for an interconnect layer for solid oxide electrolysis cells.</P>

The Influence of Changing PV Array Interconnections under a Non-uniform Irradiance

Kun Ding,Li Feng,Si-Yu Qin,Jing Mao,Jing-Wei Zhang,Xiang Wang,Tao Peng,Quan-Xin Zhai 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

Usually, the output characteristics of a photovoltaic (PV) array are significantly affected by non-uniform irradiance which is caused by ambient obstacles, clouds, orientations, tilts, etc. Some local maximum power points (LMPP) in the current-voltage (I-V) curves of a PV array can result in power losses of the array. However, the output power at the global maximum power point (GMPP) is different in different interconnection schemes in a PV array. Therefore, based on the theoretical analysis and mathematical derivation of different topological structures of a PV array, this paper investigated the output characteristics of dual series PV arrays with different interconnections. The proposed mathematical models were also validated by experimental results. Finally, this paper also concluded that in terms of performance, the total cross tied (TCT) interconnection was not always the optimal structure, especially in a dual series PV array. When one of the PV modules was severely mismatched, the TCT worked worse than the series parallel (SP) structure. This research can provide guidance for switching the interconnection to gain the greatest energy yield in a changeable- structure PV system.

Energy-Efficient Antenna Selection in Green MIMO Relaying Communication Systems

Kun Qian,Wen-Qin Wang 한국통신학회 2016 Journal of communications and networks Vol.18 No.3

In existing literature on multiple-input multiple-output(MIMO) relaying communication systems, antenna selection is oftenimplemented by maximizing the channel capacity or the outputsingle-to-noise ratio (SNR). In this paper, we propose an energyefficientlow-complexity antenna selection scheme for MIMO relayingcommunication systems. The proposed algorithm is basedon beamforming andmaximizing the Frobenius norm to jointly optimizethe transmit power, number of active antennas, and antennasubsets at the source, relaying and destination. We maximize theenergy efficiency between the link of source to relay and the linkof relay to destination to obtain the maximum energy efficiency ofthe system, subject to the SNR constraint. Compared to existingantenna selection methods forMIMO relaying communication systems,simulation results demonstrate that the proposedmethod cansave more power in term of energy efficiency, while having lowercomputational complexity.

Joint Uplink and Downlink Resource Allocation in Data and Energy Integrated Communication Networks

( Qin Yu ),( Kesi Lv ),( Jie Hu ),( Kun Yang ),( Xuemin Hong ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.6

In this paper, we propose a joint power control strategy for both the uplink and downlink transmission by considering the energy requirements of the user equipments` uplink data transmissions in data and energy integrated communication networks (DEINs). In DEINs, the base station (BS) adopts the power splitting (PS) aided simultaneous wireless information and power transfer (SWIPT) technique in the downlink (DL) transmissions, while the user equipments (UEs) carry out their own uplink (UL) transmissions by exploiting the energy harvested during the BS`s DL transmissions. In our DEIN model, there are UEs served by the BS in order to fulfil both of their DL and UL transmissions. The orthogonal frequency division multiple access (OFDMA) technique is adopted for supporting the simultaneous transmissions of multiple UEs. Furthermore, a transmission frame is divided into time slots in the medium access control (MAC) layer. The mathematical model is established for maximizing the sum-throughput of the UEs` DL transmissions and for ensuring their fairness during a single transmission frame , respectively. In order to achieve these goals, in each transmission frame T, we optimally allocate the BS`s power for each subcarrier and the PS factor for each UE during a specific time slot. The original optimisation problems are transformed into convex forms, which can be perfectly solved by convex optimisation theories. Our numerical results compare the optimal results by conceiving the objective of maximising the sum-throughput and those by conceiving the objective of maximising the fair-throughput. Furthermore, our numerical results also reveal the inherent tradeoff between the DL and the UL transmissions.

Transcriptomics Analysis Identified Candidate Genes Colocalized with Seed Dormancy QTLs in Rice (Oryza sativa L.)

Huaide Qin,Fuqing Wu,Kun Xie,Zhijun Cheng,Xiuping Guo,Xin Zhang,Jie Wang,Cailin Lei,Jiulin Wang,Long Mao,Ling Jiang,Jianmin Wan 한국식물학회 2010 Journal of Plant Biology Vol.54 No.5

Rice seed dormancy is an important trait related to the preharvest sprouting resistance of rice and is controlled by a polygene network. To identify the genes involved in this process, transcriptome analysis was applied to strong seed dormancy indica cultivar N22 and its weak dormancy mutant Q4646. The results showed that 280genes were significantly upregulated and 244 genes significantly downregulated in the seed of Q4646 as compared to N22 during 25 to 28 days after heading. These genes were mainly involved in stress response, Ccompound metabolism, plant development, DNA processing,and lipid metabolism. Some of these genes were colocalized with several reported dormancy QTLs, suggesting that they are possibly candidate genes underlying rice seed dormancy. Our work provides important clues for future effort to clone seed dormant genes in rice.

The Influence of Changing PV Array Interconnections under a Non-uniform Irradiance

Ding, Kun,Feng, Li,Qin, Si-Yu,Mao, Jing,Zhang, Jing-Wei,Wang, Xiang,Peng, Tao,Zhai, Quan-Xin The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

Usually, the output characteristics of a photovoltaic (PV) array are significantly affected by non-uniform irradiance which is caused by ambient obstacles, clouds, orientations, tilts, etc. Some local maximum power points (LMPP) in the current-voltage (I-V) curves of a PV array can result in power losses of the array. However, the output power at the global maximum power point (GMPP) is different in different interconnection schemes in a PV array. Therefore, based on the theoretical analysis and mathematical derivation of different topological structures of a PV array, this paper investigated the output characteristics of dual series PV arrays with different interconnections. The proposed mathematical models were also validated by experimental results. Finally, this paper also concluded that in terms of performance, the total cross tied (TCT) interconnection was not always the optimal structure, especially in a dual series PV array. When one of the PV modules was severely mismatched, the TCT worked worse than the series parallel (SP) structure. This research can provide guidance for switching the interconnection to gain the greatest energy yield in a changeable- structure PV system.

Prognostic Significance of CYFRA21-1, CEA and Hemoglobin in Patients with Esophageal Squamous Cancer Undergoing Concurrent Chemoradiotherapy

Zhang, Hai-Qin,Wang, Ren-Ben,Yan, Hong-Jiang,Zhao, Wei,Zhu, Kun-Li,Jiang, Shu-Mei,Hu, Xi-Gang,Yu, Jin-Ming Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.1

Purpose: To evaluate the prognostic value of serum CYFRA21-1, CEA and hemoglobin levels regarding long-term survival of patients with esophageal squamous cell carcinoma (ESCC) treated with concurrent chemoradiotherapy (CRT). Methods: Age, gender, Karnofsky Performance Status (KPS), tumor location, tumor length, T stage, N stage and serum hemoglobin, and CYFRA21-1 and CEA levels before concurrent CRT were retrospectively investigated and related to outcome in 113 patients receiving 5-fluorouracil and cisplatin combined with radiotherapy for ESCC. The Kaplan-Meier method was used to analyze prognosis, the log-rank to compare groups, the Cox proportional hazards model for multivariate analysis, and ROC curve analysis for assessment of predictive performance of biologic markers. Results: The median survival time was 20.1 months and the 1-, 2-, 3-, 5- year overall survival rates were 66.4%, 43.4%, 31.9% and 15.0%, respectively. Univariate analysis showed that factors associated with prognosis were KPS, tumor length, T-stage, N-stage, hemoglobin, CYFRA21-1 and CEA level. Multivariate analysis showed T-stage, N-stage, hemoglobin, CYFRA21-1 and CEA level were independent predictors of prognosis. By ROC curve, CYFRA21-1 and hemoglobin showed better predictive performance for OS than CEA (AUC= 0.791, 0.704, 0.545; P=0.000, 0.000, 0.409). Conclusions: Of all clinicopathological and molecular factors, T stage, N stage, hemoglobin, CYFRA21-1 and CEA level were independent predictors of prognosis for patients with ESCC treated with concurrent CRT. Among biomarkers, CYFRA21-1 and hemoglobin may have a better predictive potential than CEA for long-term outcomes.

Age of Diagnosis of Breast Cancer in China: Almost 10 Years Earlier than in the United States and the European Union

Song, Qing-Kun,Li, Jing,Huang, Rong,Fan, Jin-Hu,Zheng, Rong-Shou,Zhang, Bao-Ning,Zhang, Bin,Tang, Zhong-Hua,Xie, Xiao-Ming,Yang, Hong-Jian,He, Jian-Jun,Li, Hui,Li, Jia-Yuan,Qiao, You-Lin,Chen, Wan-Qin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22

Background: The study aimed to describe the age distribution of breast cancer diagnosis among Chinese females for comparison with the United States and the European Union, and provide evidence for the screening target population in China. Materials and Methods: Median age was estimated from hospital databases from 7 tertiary hospitals in China. Population-based data in China, United States and European Union was extracted from the National Central Cancer Registry, SEER program and GLOBOCAN 2008, respectively. Age-standardized distribution of breast cancer at diagnosis in the 3 areas was estimated based on the World Standard Population 2000. Results: The median age of breast cancer at diagnosis was around 50 in China, nearly 10 years earlier than United States and European Union. The diagnosis age in China did not vary between subgroups of calendar year, region and pathological characteristics. With adjustment for population structure, median age of breast cancer at diagnosis was 50~54 in China, but 55~59 in United States and European Union. Conclusions: The median diagnosis age of female breast cancer is much earlier in China than in the United States and the European Union pointing to racial differences in genetics and lifestyle. Screening programs should start at an earlier age for Chinese women and age disparities between Chinese and Western women warrant further studies.

17cc급 자동차용 압축기 내구성능 최적화에 관한 연구

양용군(Yong-Kun Yang),우위팅(Yu-Ting Wu),진진(Zhen Qin),류성기(Sung-Ki Lyu) 한국기계가공학회 2021 한국기계가공학회지 Vol.20 No.3

The fuel economy is a key issue for the automotive industry due to environmental concerns. In particular, only 5-20% of the energy generated in a car using an internal combustion engine is used as power, and the remaining energy is dissipated due to friction with other parts. The main components in the reciprocating piston type compressors commonly used in general vehicles include shafts, swash plates, pistons, and cylinders, and severe friction loss occurs due to the contact of these components. Generally, the wear contact is the maximum between the shaft and cylinder and between the piston and swash plate. The friction of these parts may cause quality problems and deteriorate the durability. In this study, to reduce the frictional loss, a prototype with additional coating agents was produced. Moreover, an optimized design was generated, and performance, noise, and durability tests were conducted. A more durable product was successfully obtained.