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Search Results: 1 - 10 of 81131 matches for " SHEN Yan-Jun "
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Solving Project Scheduling Problems using Estimation of Distribution Algorithm with Local Simplex Search
Yan-Jun Shi,Guo-Jiang Shen,Wang Chen
Information Technology Journal , 2011,
Abstract: The Resource-Constrained Project Scheduling Problem (RCPSP) is a NP-hard problem in information engineering. The activities of a project have to be scheduled for satisfying all the precedence and resource constraints. We presented a heuristic algorithm (EDAS) to deal with this problem which employed an estimation of distribution algorithm (known as EDA) and improved the local search capacity with a simplex search. In this algorithm, the EDA firstly searched the solution space and generated activity lists to provide the initial population; then, the EDA selected the sample solutions to build a probability distribution model. The new individual was generated by sampling this model. The simplex search was used to enhance the local search capacity of the EDA. Compared with state-of-the-art algorithms available in the literature, we showed the effectiveness of this approach empirically on the standard benchmark problems of size J60 and J120 from PSPLIB.
CARM1 Mediates Modulation of Sox2
Hai-yong Zhao, Yan-jun Zhang, Hui Dai, Ye Zhang, Yu-fei Shen
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0027026
Abstract: Sox2 is a key component of the transcription factor network that maintains the pluripotent state of embryonic stem cells (ESCs). Sox2 is regulated by multiple post-translational modifications, including ubiquitination, sumoylation, acetylation and phosphorylation. Here we report that Sox2 is in association with and methylated by coactivator-associated arginine methyltransferase 1 (CARM1), a protein arginine methyltransferase that plays a pivotal role in ESCs. We found that CARM1 facilitates Sox2-mediated transactivation and directly methylates Sox2 at arginine 113. This methylation event enhances Sox2 self-association. Furthermore, the physiological retention of Sox2 on chromatin restricts the Sox2 methylation level. Our study reveals the direct regulation of Sox2 by CARM1 that sheds lights on how arginine methylation signals are integrated into the pluripotent transcription factor network.
Soil moisture monitoring in agricultural lands via active-passive microwave remote sensing
主被动微波遥感在农区土壤水分监测中的应用初探

GUO Ying,SHEN Yan-Jun,ZHAO Chao,
郭英
,沈彦俊,赵超

中国生态农业学报 , 2011,
Abstract: Soil moisture is a critical element for monitoring crop growth and drought in agricultural lands.Microwave remote sens-ing is a reliable mode of retrieving soil moisture in real time and under all weather and physiographic conditions.Retrieving soil moisture via combined active and passive microwave remote sensing has the advantage of high spatial resolution and real-time mea-surement at regional scale.Although it has practical significance for agricultural lands,this technique has largely been previously a...
Agro-ecosystems water cycles of the typical irrigated farmland in the North China Plain
华北平原典型井灌区农田水循环过程研究回顾

SHEN Yan-Jun,LIU Chang-Ming,
沈彦俊
,刘昌明

中国生态农业学报 , 2011,
Abstract: This paper reviewed the research progresses on hydrological cycles and water transformation studies at Luancheng Agro-Ecosystem Experimental Station, Chinese Academy of Sciences (simplified as Luancheng Station) during the past 30 years. As a mostly achieved progress, the evapotranspiration (ET) and its partitioning over irrigated winter wheat-summer maize cropland, which is the most common cultivation pattern in North China Plain, are clarified through multi-years observations using weighing lysimeter, micrometeorological measurements, and isotopic analysis. The annual ET of the irrigated wheat-maize field can reach to 870 mm·a-1, which exceeds the annual precipitation by around 350 mm at an average level. This gap between annual ET and precipitation is bridged by groundwater pumpage. As a matter of long-term over exploitation, the groundwater over the North China Plain experienced rapid depletion and caused wide concerns on sustainability. The study at Luancheng Station suggests that the soil evaporation shares about 1/3 of the total water consumption and the evaporation depth can reach deep to 20 cm under land surface through a isotopic method. Moreover, wheat transpiration is mainly dependent on the soil moisture in the depth of 0~40 cm soil layer, which is largely shallower than the generally used "planing wetting depth", i.e. 100 cm. As for the deep percolation or drainage of the soil water and the vertical recharge rate of groundwater, there exists large range among different studies with different method, such as soil water balance modeling, rainfall-infiltration experiment, etc. It is urgently needed to go to the details of water cycles over different agricultural land uses and soil properties, and to address the spatial heterogeneities in evapotranspiration, infiltration, and soil water balancing, over the plain.
Impact of climate warming on temperature and heat resource in arid Northwest China
气候变暖对西北干旱区农业热量资源变化的影响

LI Shuo,SHEN Yan-Jun,
李 硕
,沈彦俊

中国生态农业学报 , 2013,
Abstract: 气候变暖将改变农业气候资源尤其是热量资源的时空分布。本文通过分析西北干旱区67个气象站点的气象数据,研究了西北干旱区近50年气温、积温、霜冻的变化特征与规律。结果表明,西北干旱区气温呈上升趋势,上升幅度为0.33℃.10a 1,高于全国平均水平,其中北疆增温幅度大于其他地区。年内变化上,冬季增温幅度最大。近50年,西北干旱区≥0℃、≥10℃积温变化率分别为67.8℃.10a 1和68.8℃.10a 1,≥0℃和≥10℃积温持续的时间也呈增加趋势,其中≥0℃积温持续天数的增加主要是由于结束日期的推迟引起的,而≥10℃积温天数的增加主要是因为初始日期的提前。研究区无霜期呈增加趋势,主要表现为初霜日的延迟和终霜日的提前,其趋势分别可达2 d.10a 1和1.4 d.10a 1,前者贡献略大。西北干旱区初霜出现日期的年际波动小于终霜日,终霜出现日期晚于≥10℃积温开始日期约10 d,且气温变暖的趋势并没有引起这一状况的改变,而多数站点≥10℃积温结束日期早于初霜开始日期。
A Modified Artificial Bee Colony Algorithm for Vehicle Routing Problems with Time Windows
Yan-Jun Shi,Fan-Wei Meng,Guo-Jiang Shen
Information Technology Journal , 2012,
Abstract: Vehicle routing problems with time windows (VRPTW for short) is an NP-hard problem and an extension of vehicle routing problems. This study presented a heuristic algorithm (ABC-T) to deal with vehicle routing problems with time windows. The ABC-T algorithm employed the artificial bee colony algorithm (known as ABC) and improved the global search capacity with tournament selection strategy. In this algorithm, the employed bees generated the new solutions by the neighborhood search; then, based on the tournament selection strategy, the food source selection probability was settled. Finally, the new solution was generated by the onlooker bees. The tournament selection strategy was used here to enhance the global search capacity of the ABC. Compared with the state-of-the-art algorithms available in the literature, the effectiveness of this approach was showed on the Solomon’s R102 problem.
3-Aminopyridinium picrate
Yan-jun Li
Acta Crystallographica Section E , 2010, DOI: 10.1107/s1600536810037190
Abstract: During the formation of the title compound, C5H7N2+·C6H2N3O7 , a phenolic proton is transferred to the pyridine N atom. In the crystal structure, the ions are linked by intermolecular N—H...O and N—H...(O,O) hydrogen bonds into layers running parallel to (100). These layers are connected by weak π–π stacking interactions between symmetry-related pyridine and picric benzene rings with a centroid–centroid distance of 3.758 (2) , forming a three-dimensional network.
4-Nitroaniline–picric acid (2/1)
Yan-jun Li
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809037416
Abstract: In the title adduct, C6H3N3O7·0.5C6H6N2O2, the complete 4-nitroaniline molecule is generated by a crystallographic twofold axis with two C atoms and two N atoms lying on the axis. The molecular components are linked into two dimensional corrugated layers running parallel to the (001) plane by a combination of intermolecular N—H...O and C—H...O hydrogen bonds. The phenolic oxygen and two sets of nitro oxygen atoms in the picric acid were found to be disordered with occupancies of 0.81 (2):0.19 (2) and 0.55 (3):0.45 (3) and 0.77 (4):0.23 (4), respectively.
Fouling and cleaning of membrane--a literature review
ZHAO Yan-jun,WU Kai-fen,WANG Zheng-jun,ZHAO Liang,LI Shu-shen,
ZHAO Yan-jun
,WU Kai-fen,WANG Zheng-jun,ZHAO Liang,LI Shu-shen

环境科学学报(英文版) , 2000,
Abstract: Membrane fouling curtails severely the economical and practical implementation of membrane process. The fundamental principles and mechanisms of membrane fouling as well as factors affecting fouling have been summarized in this paper. It also has covered three fouling resistance models and four kinds of approaches to improve membrane performance. Membrane cleaning methods are also discussed including physical, chemical, physico\|chemical and biological methods. In the four groups of basic cleaning methods, biological cleaning has considerable advantages and potentials. Extensive research work should be carried out further to explore and develop new ideas and techniques in the field of membrane cleaning and restoration.
Depopulation of rural areas under the backdrop of urbanization——A case study of Kangbao County, Northwest of Hebei Province
城市化背景下农牧交错带农村聚落过疏化问题研究——以冀西北康保县为例

PEI Hong-Wei,CHANG Chun-Ping,HE Wen-Hui,SHEN Yan-Jun,SHEN Yan-Jun,
裴宏伟
,常春平,贺文慧,沈彦军,沈彦俊

中国生态农业学报 , 2009,
Abstract: To understand the issues and driving factors of rural depopulation (a universal phenomenon in the rural areas of every nation under the backdrop of urbanization), we surveyed 19 villages in Kangbao County, Hebei Province. The villages are in the farming pastoral interlocks of North China where the ecology is fragile and the economic backward. The number of idle houses and the degree of damaged house were quantitatively analyzed. The survey shows that the proportion of idle brick houses to total brick houses is 0.360, and that of earthen houses to total usable earthen house is 0.254. That for dilapidated houses to total houses is 0.350. Depopulation of the rural villages in the farming pastoral interlocks of North China has the following characteristics: The extent of depopulation is in direct correlation with farmer income level. Low and slow economic development is the fundamental cause of depopulation in the area. Labor loss has resulted in severe dilapidation of village landscape and resource waste. Depopulation has severely retarded normal orders of rural production and life.
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