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党执政能力建设视阈下的核心意识研究
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作者 王玉堂 《湖南涉外经济学院学报》 2019年第1期46-52,共7页
增强核心意识,维护核心权威,是马克思主义政党执政能力建设的一个重要维度。增强核心意识,最根本的是做到'两个坚决维护'。共产党人的核心意识不是自发形成的,而是以坚定的理想信念作支撑,在长期的学习、实践、党性锻炼和政治... 增强核心意识,维护核心权威,是马克思主义政党执政能力建设的一个重要维度。增强核心意识,最根本的是做到'两个坚决维护'。共产党人的核心意识不是自发形成的,而是以坚定的理想信念作支撑,在长期的学习、实践、党性锻炼和政治历练中逐步形成的,有着深厚的思想、政治和道德底蕴。增强核心意识,是一个政治命题,也是一个实践命题,必须体现在具体工作中和实际行动上。 展开更多
关键词 执政能力 核心 核心意识 领导核心
Approach to 2′-(Dialkylamino)-1-alkyl-4′H-spiro[indoline-3,5′-oxazole]-2,4′-diones and 1,3-Oxazin-4-ones via Cyclization of Vilsmeier Salts withα-Hydroxy andβ-Carbonyl Amides
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作者 DAI Jianan LIU Bengen +4 位作者 WEI Zhonglin CAO Jungang LIANG Dapeng DUAN Haifeng LIN Yingjie 《高等学校化学研究:英文版》 SCIE CAS CSCD 2019年第2期216-220,共5页
A straiglitforward and efficient synthetic method of 2′-(dialkylammo)-l-alkyl-4′H-spiro[indoline-3,5′-oxazole]-2,4′-diones and 2-(dialkylamino)-5,6-dihydro-4H-naphtho[2,1-e][1,3]oxazin-4-one-derivatives have been ... A straiglitforward and efficient synthetic method of 2′-(dialkylammo)-l-alkyl-4′H-spiro[indoline-3,5′-oxazole]-2,4′-diones and 2-(dialkylamino)-5,6-dihydro-4H-naphtho[2,1-e][1,3]oxazin-4-one-derivatives have been developed from a-hydroxy andβ-carbonyl amides and various Vilsmeier salts.A wide range of heterocyclic compounds were obtained in excellent yields(up to 97%),which will provide promising candidates lor chemical biology and drug discovery. 展开更多
关键词 SPIROOXINDOLE unit 2-Oxazolin-4-ones CORE STRUCTURE 3-Oxazin-4-ones CORE STRUCTURE
辽河油田D66块火驱开发储层取心技术 预览
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作者 石林 《石油钻采工艺》 CAS 北大核心 2019年第2期143-146,共4页
为了提高火驱开发地层岩心收获率,分析了火驱对D66块地层的影响,在此基础上,有针对性地对取心工具进行了改进,对钻井参数进行了优化,并完成了3口井的取心实践。研究表明,火驱对D66块杜家台油层改造作用较大,主要表现在3个方面:一是火驱... 为了提高火驱开发地层岩心收获率,分析了火驱对D66块地层的影响,在此基础上,有针对性地对取心工具进行了改进,对钻井参数进行了优化,并完成了3口井的取心实践。研究表明,火驱对D66块杜家台油层改造作用较大,主要表现在3个方面:一是火驱导致地层温度大幅度升高;二是高温烘烤作用使蒙皂石快速脱水后,遇水快速膨胀,胶结物因此裂开失去胶结作用,导致地层变得松散;三是火驱形成的高温强碱环境,使岩石骨架颗粒石英发生溶解,导致地层变得松散甚至垮塌。针对火驱后的高温松散地层综合应用耐高温密闭液、防冲蚀钻头、复合式岩心爪、铝合金内筒和PVC内衬管等取心工具,结合“高钻压、低钻速、小排量”的钻井参数设计,岩心收获率可以达到77.96%~88.32%,比常规取心提高约44~54.36个百分点。本文旨在通过对D66块火驱后地层取心的成功经验进行总结,为其他地区火驱后地层的取心提供借鉴。 展开更多
关键词 岩心 火驱 火烧油层 取心 收获率 辽河油田
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On Characterizations of Special Elements in Rings with Involution
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作者 Sanzhang XU Jianlong CHEN Dijana MOSIC 《数学年刊:B辑英文版》 SCIE CSCD 2019年第1期65-78,共14页
Let R be a ring with involution. It is well-known that an EP element in R is a core invertible element, but the question when a core invertible element is an EP element,the authors answer in this paper. Several new ch... Let R be a ring with involution. It is well-known that an EP element in R is a core invertible element, but the question when a core invertible element is an EP element,the authors answer in this paper. Several new characterizations of star-core, normal and Hermitian elements in R are also presented. 展开更多
关键词 Moore-Penrose INVERSE Core INVERSE EP ELEMENT Star-core ELEMENT Normal ELEMENT HERMITIAN ELEMENT
The effect of the differential rotation of the earth inner core on the free core nutation
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作者 Mian Zhang Chengli Huang 《大地测量与地球动力学:英文版》 2019年第2期146-149,共4页
Seismic observations shows that the inner core rotates faster than the mantle and the rotation axis of the inner core may not align with the rotation axis of the mantle. Free core nutation reflects core’s information... Seismic observations shows that the inner core rotates faster than the mantle and the rotation axis of the inner core may not align with the rotation axis of the mantle. Free core nutation reflects core’s information. We discuss the effect of the inner core’s differential rotation on free core nutation from two aspects: rotation speed and deflection angle. Our result shows it is in accordance with the observations when the inner core’s rotation speed doesn’t exceed 10° faster than mantle’s per year, and the deflection angle is less than 1°,if the rotation speed and the deflection angle are respectively considered separately. 展开更多
关键词 INNER CORE DIFFERENTIAL ROTATION Free CORE NUTATION
Harnessing the Future 预览
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作者 CHEN JUN 《今日中国:英文版》 2019年第4期24-27,共4页
ON the 50 Smartest Companies 2017 list unveiled by the world’s top technology review journal MIT Technology Review, iFlytek, a Chinese company dedicated to voice assistant technology, ranked first in China and sixth ... ON the 50 Smartest Companies 2017 list unveiled by the world’s top technology review journal MIT Technology Review, iFlytek, a Chinese company dedicated to voice assistant technology, ranked first in China and sixth in the world. In 2018, iFlyteck performed the best in 12 international authoritative technology competitions thanks to its continued breakthroughs and internationally leading core technology. 展开更多
关键词 FUTURE MIT CORE TECHNOLOGY
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Hepatitis C virus antigens enzyme immunoassay for one-step diagnosis of hepatitis C virus coinfection in human immunodeficiency virus infected individuals 预览
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作者 Ke-Qin Hu Wei Cui +1 位作者 Susan D Rouster Kenneth E Sherman 《世界肝病学杂志:英文版(电子版)》 2019年第5期442-449,共8页
BACKGROUND Current diagnosis of hepatitis C virus(HCV)infection requires two sequential steps:testing for anti-HCV followed by HCV RNA PCR to confirm viremia.We have developed a highly sensitive and specific HCV-antig... BACKGROUND Current diagnosis of hepatitis C virus(HCV)infection requires two sequential steps:testing for anti-HCV followed by HCV RNA PCR to confirm viremia.We have developed a highly sensitive and specific HCV-antigens enzyme immunoassay(HCV-Ags EIA)for one-step diagnosis of viremic HCV infection.AIM To assess the clinical application of the HCV-Ags EIA in one-step diagnosis of viremic HCV infection in human immunodeficiency virus(HIV)-coinfected individuals.METHODS The study blindly tested HCV-Ags EIA for its performance in one-step diagnosing viremic HCV infection in 147 sera:10 without HCV or HIV infection;54 with viremic HCV monoinfection;38 with viremic HCV/HIV coinfection;and 45 with viremic HCV and non-viremic HIV coinfection.RESULTS Upon decoding,it was 100%accordance of HCV-Ags EIA to HCV infection status by HCV RNA PCR test.In five sera with HCV infection,HCV RNA was as low as 50-59 IU/mL,and four out of five tested positive for HCV-Ags EIA.Likewise,it was also 100%accordance of HCV-Ags EIA to HCV infection status by HCV RNA PCR in 83 sera with HCV and HIV coinfection,regardless if HIV infection was active or not.CONCLUSION The modified HCV-Ags EIA has a lower detection limit equivalent to serum HCV RNA levels of approximately 100 IU/mL.It is highly sensitive and specific in the setting of HIV coinfection,regardless of HIV infection status and CD4 count.These data support the clinical application of the HCV-Ags EIA in one-step diagnosis of HCV infection in HIV-infected individuals. 展开更多
关键词 HEPATITIS C VIRUS HEPATITIS C VIRUS ANTIGENS HEPATITIS C VIRUS core antigen HEPATITIS C VIRUS DIAGNOSTIC test DIAGNOSTIC assay Enzyme immunoassay
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A Liutex based definition and identification of vortex core center lines 预览
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作者 Yi-sheng Gao Jian-ming Liu +1 位作者 Yi-fei Yu Chaoqun Liu 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第3期445-454,共10页
Six core issues for vortex definition and identification concern with (1) the absolute strength,(2) the relative strength,(3) the rotational axis,(4) the vortex core center,(5) the vortex core size, and (6) the vortex... Six core issues for vortex definition and identification concern with (1) the absolute strength,(2) the relative strength,(3) the rotational axis,(4) the vortex core center,(5) the vortex core size, and (6) the vortex boundary (Liu C. 2019). However, most of the currently popular vortex identification methods, including the Q criterion, the criterion and the Acj criterion etc., are Eulerian local region-type vortex identification criteria and can only approximately identify the vortex boundary by somewhat arbitrary threshold. On the other hand, the existing Eulerian local line-type methods, which seek to extract line-type features such as vortex core line, are not entirely satisfactory since most of these methods are based on vorticity or pressure minimum that will fail in many cases. The key issue is the lack of a reasonable mathematical definition for vortex core center. To address this issue, a Liutex (previously named Rortex) based definition of vortex core center is proposed in this paper. The vortex core center, also called vortex rotation axis line here, is defined as a line where the Liutex magnitude gradient vector is aligned with the Liutex vector, which mathematically implies that the cross product of the Liutex magnitude gradient vector and the Liutex vector on the line is equal to zero. Based on this definition, a novel three-step method for extracting vortex rotation axis lines is presented. Two test cases, namely the Burgers vortex and hairpin vortices, are examined to justify the proposed method. The results demonstrate that the proposed method can successfully identify vortex rotation axis lines without any user-specified threshold, so that the proposed method is very straightforward, robust and efficient. 展开更多
关键词 VORTEX DEFINITION VORTEX IDENTIFICATION flow visualization Liutex Liutex MAGNITUDE GRADIENT VORTEX core LINES
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变压器中低频电磁暂态模型研究综述 预览
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作者 张国栋 刘凯 《浙江电力》 2019年第1期70-75,共6页
受铁磁材料的影响,变压器在电磁暂态过程中表现出很强的非线性和频率相关性,因而变压器的建模也成为电力仿真软件的薄弱环节之一,以致目前尚无任何一种模型能适用于各种运行工况。为了明确不同模型的适用范围,归纳总结了变压器中低频电... 受铁磁材料的影响,变压器在电磁暂态过程中表现出很强的非线性和频率相关性,因而变压器的建模也成为电力仿真软件的薄弱环节之一,以致目前尚无任何一种模型能适用于各种运行工况。为了明确不同模型的适用范围,归纳总结了变压器中低频电磁暂态模型的基本原理,并研究了对变压器电磁暂态模型有重要影响的漏电感模型、铁心模型和损耗模型,最后给出了不同模型的适用条件。 展开更多
关键词 变压器 中低频 电磁暂态模型 漏电感 铁心 损耗
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青龙台油田疏松砂岩储层敏感性分析 预览
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作者 王玲 《重庆科技学院学报:自然科学版》 CAS 2019年第1期21-24,共4页
针对青龙台油田的地质特征,利用沙三段储层取心岩样,进行储层敏感性室内实验,测试分析了储层的速敏性、水敏性、盐敏性、酸敏性、碱敏性。结果表明,沙三段油层具有弱-中等偏弱速敏,中等偏强-强水敏,中等偏弱酸敏,中等偏强-强碱敏。鉴于... 针对青龙台油田的地质特征,利用沙三段储层取心岩样,进行储层敏感性室内实验,测试分析了储层的速敏性、水敏性、盐敏性、酸敏性、碱敏性。结果表明,沙三段油层具有弱-中等偏弱速敏,中等偏强-强水敏,中等偏弱酸敏,中等偏强-强碱敏。鉴于该区储层疏松易出砂及其敏感性特点,为保护储层,建议严格控制注采速度在10md以下;入井流体的矿化度不应低于5000mgL,pH不应高于8.5。 展开更多
关键词 青龙台油田 沙三段 疏松砂岩 储层敏感性 岩心 实验
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Histopathological characteristics of needle core biopsy and surgical specimens from patients with solitary hepatocellular carcinoma or intrahepatic cholangiocarcinoma 预览
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作者 Ju-Shan Wu Ji-Liang Feng +3 位作者 Rui-Dong Zhu San-Guang Liu Da-Wei Zhao Ning Li 《世界胃肠肿瘤学杂志:英文版(电子版)》 CAS 2019年第5期404-415,共12页
BACKGROUND Pathological manifestations of hepatic tumours are often associated with prognosis. Although surgical specimens (SS) can provide more information, currently, pre-treatment needle core biopsy (NCB) is increa... BACKGROUND Pathological manifestations of hepatic tumours are often associated with prognosis. Although surgical specimens (SS) can provide more information, currently, pre-treatment needle core biopsy (NCB) is increasingly showing important value in understanding the nature of liver tumors and even in diagnosis and treatment decisions. However, the concordance of the clinicopathological characteristics and immunohistochemical (IHC) staining between NCB and SS from patients with hepatic tumours were less concerned. AIM To introduce a more accurate method for interpreting the IHC staining results in order to improve the diagnostic value of hepatic malignancy in NCB samples. METHOD A total of 208 patients who underwent both preoperative NCB and surgical resection for hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma RESULTS Morphologically, the presence of compact tumour nests or a cord-like structure in NCB was considered the primary cause of misdiagnosis of HCC from ICC. The kappa statistic showed a moderate agreement in histomorphology (k = 0.504) and histological grade (k = 0.488) between NCB and SS of the tumours. A 4-tier (+++,++,+, and -) scoring scheme that emphasized the focal neoplastic cell immunoreactivity of tumour cells revealed perfect concordance of CK19, GPC3 and HepPar1 between NCB and SS (k = 0.717;k = 0.768;k = 0.633). Furthermore, with the aid of a binary classification derived from the 4-tier score, a high concordance was achieved in interpreting the IHC staining of the three markers between NCB and final SS (k = 0.931;k = 0.907;k = 0.803), increasing the accuracy of NCB diagnosis C (k = 0.987;area under the curve = 0.997, 95%CI: 0.990-1.000;P < 0.001). CONCLUSION These findings imply that reasonable interpretation of IHC results in NCB is vital for improving the accuracy of tumour diagnosis. The simplified binary classification provides an easy and applicable approach. 展开更多
关键词 HISTOPATHOLOGICAL Needle core biopsy SURGICAL SPECIMENS SOLITARY hepatocellular carcinoma INTRAHEPATIC CHOLANGIOCARCINOMA
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缠绕式温等静压机工作缸热机耦合分析 预览
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作者 鲍延年 罗天洪 刘遵飞 《计算机仿真》 北大核心 2019年第7期104-108,212共6页
针对温度-压力热机耦合工况下应力集中的问题,提出多应力场作用下的工作缸热机耦合分析算法,构建工作缸的应力耦合模型。基于钢带缠绕理论、非线性弹性理论及热弹性理论,探索缠绕式温等静压机工作缸负载工况下应力破坏机理,分析缠绕式... 针对温度-压力热机耦合工况下应力集中的问题,提出多应力场作用下的工作缸热机耦合分析算法,构建工作缸的应力耦合模型。基于钢带缠绕理论、非线性弹性理论及热弹性理论,探索缠绕式温等静压机工作缸负载工况下应力破坏机理,分析缠绕式温等静压机工作缸在三种典型的工况下的应力分布情况。利用ABAQUS对缠绕式工作缸的工作过程进行热机耦合分析,揭示工作缸在应力-温度场作用下缠绕层和芯筒之间的映射关系。对比仿真和试验结果,研究表明:实验数据与仿真结果基本吻合,为工作缸进一步优化设计提供了坚实的理论基础。 展开更多
关键词 机械工程 预应力钢丝缠绕 热机耦合 应力场 工作缸
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Hard IP Core Nondestructive Testing Technology 预览
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作者 Kun Yu Hua Wang 《微电子制造学报》 2019年第2期1-6,共6页
Based on the analysis of the existing hard IP core testing technology, the hard IP core nondestructive testing technology was studied, according to the verification requirements of a large number of hard IP core preci... Based on the analysis of the existing hard IP core testing technology, the hard IP core nondestructive testing technology was studied, according to the verification requirements of a large number of hard IP core precise and fast testing. Combined with the external automatic test equipment (ATE) and the on-chip evaluation circuit, a general evaluation system of simulating user system on chip (SOC) with signal timing calibration and compensation by software and hardware compensation structures were introduced to realize the function, performance and reliability verification of the hard IP core. The design and verification of a random access memory (SRAM) hard IP core based on an on-chip evaluation circuit was actually completed, and the key timing parameters of the hard IP core were tested. The address setup time parameter was taken as an example to analyze the specific testing method and the test results were obtained. With this testing technology, the accuracy of testing the timing parameters of hard IP core can reach pS level, compared with the hard IP core packaged test, the accuracy of the result data is fully reflected. 展开更多
关键词 HARD IP core system on CHIP (SOC) testing technology evaluation circuit MEMORY automatic test equipment (ATE).
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Application of the Computer Application Technology in the Enterprise Informatization 预览
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作者 WEI Yanying 《国际英语教育研究:英文版》 2019年第2期1-3,共3页
With the rapid development of our society and the economy,the competitions among enterprises are becoming fiercer and fiercer.In order to take the lead in the fiercely competitive market economy,enterprises must keep ... With the rapid development of our society and the economy,the competitions among enterprises are becoming fiercer and fiercer.In order to take the lead in the fiercely competitive market economy,enterprises must keep pace with the times and constantly introduce the advanced technologies to improve their core competitiveness.Through the enterprise informatization,enterprises have achieved the remarkable results in improving their working qualities,working efficiency and controlling cost expenditure.In this context,the application of the computer application technologies in the enterprise informatization is analyzed to a certain extent,in order to promote enterprises to strengthen the construction of informatization,and then better respond to the latest challenges faced by enterprises under the background of the rapid development of the modem economy. 展开更多
关键词 COMPUTER APPLICATION technology ENTERPRISE INFORMATION construction APPLICATION CORE COMPETITIVENESS
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Analysis of drying and saturating natural gypsum samples for mechanical testing 预览
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作者 Mohammadhossein Sadeghiamirshahidi Stanley J.Vitton 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第2期219-227,共9页
The stability of underground abandoned gypsum mines is dependent on the gypsum pillar’s strength,and most abandoned mines are in a fully saturated condition.Moisture affects the strength of gypsum and is therefore co... The stability of underground abandoned gypsum mines is dependent on the gypsum pillar’s strength,and most abandoned mines are in a fully saturated condition.Moisture affects the strength of gypsum and is therefore commonly measured when testing rock strength.For most rocks,this is a simple task of weighing the rock’s mass before and after oven-heating at a specified temperature and duration.For natural gypsum,however,this is not a straightforward process.Heating natural gypsum can result in dehydration and transformation of gypsum to hemihydrate and anhydrite,thus changing the physical characteristics of the gypsum such as its particle density which in turn affects the moisture content and strength measurements.To prevent transformation when determining the moisture content of gypsum,the American Society for Testing Materials(ASTM)recommends lowering the drying temperature from 110℃to 60℃.To investigate the temperature at which gypsum transforms to hemihydrate,we used a helium pycnometer to measure the particle densities of gypsum,hemihydrate and anhydrite.In this research,we suggest that a higher drying temperature of 80℃can be used for drying gypsum without transforming gypsum to hemihydrate.Further,preparing saturated samples for mechanical testing,which is required in stability analyses of abandoned mines,is challenging due to the dissolution of gypsum when placed in water.To address this problem,we investigated the following methods to saturate gypsum cores taking into account the solubility of gypsum:(1)water immersion,(2)vacuum saturation,and(3)improved vacuum saturation.The research indicates that all the three methods are acceptable but they should be conducted using a saturated gypsum-water solution to minimize dissolution.Further,the research found that the improved vacuum saturation method saturated the test samples within 24 h,while duration of 30 h was required for the other two methods. 展开更多
关键词 Gypsum-hemihydrate-anhydrite transformation DEHYDRATION Rock core SATURATION Moisture content HELIUM PYCNOMETER
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Potential gains from spatially-explicit coordinated planning between two large public ownerships in Minnesota 预览
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作者 Joshua J. Bixby Howard M. Hoganson Yu Wei 《森林生态系统:英文版》 CSCD 2019年第2期102-118,共17页
Background: Many forested landscapes throughout the world involve a mix of public forest ownerships. This study explores how coordinated planning between two large public ownerships in Minnesota impact landscape-level... Background: Many forested landscapes throughout the world involve a mix of public forest ownerships. This study explores how coordinated planning between two large public ownerships in Minnesota impact landscape-level trade-offs between timber production and production of core area of older forest (COF) for the region. COF is an important metric for wildlife habitat. Emphasis is on better understanding potential gains from both coordinated planning at the site-level where ownerships share stand boundaries and from coordinated planning at a broader policy level involving assumed values of COF by the public. The study area involves over 300,000 ha, 150,000 analysis units and a 100-year planning horizon. Methods: The concept of influence zones in modeling spatial interdependencies is described and implemented. The estimated total area of COF is assumed an important landscape metric for forest wildlife habitat condition for each forest planning period. COF has a surrounding buffer protecting it from edge effects. Differences are recognized between COF condition requirements and condition requirements for its surrounding buffer. A spatially-explicit harvest scheduling model is applied in conjunction with moving-windows techniques of GIS to find near-optimal management schedules for the large landscape. Multiple model runs are examined to help better understand both potential gains from coordinated planning and the tradeoffs between timber and COF production. Results: Results demonstrate the ability to incorporate detailed site-level COF production into management scheduling models for broad, landscape-level planning. For the study area and the assumed COF definitions, substantially larger gains are possible by coordinating COF value assumptions across ownerships, as compared to possible gains from coordinating on-the-ground management activities in areas involving shared stand boundaries. Although a general map of the study area shows a definite intertwining mosaic of ownership by the two large public agencies, a deta 展开更多
关键词 Core area Interior space Trade-off analysis Multiple objective PLANNING Landscape PLANNING HARVEST scheduling PATCH size Production possibilities FRONTIER
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BS22号科钻井提高岩芯基线长度技术 预览
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作者 肖长城 贾中芳 《西部探矿工程》 CAS 2019年第1期77-79,86共4页
算井子地段花岗岩深部环境钻探工程属于国家科研项目,项目要求钻孔所取岩芯必须严丝合缝可拼合,并在岩芯上画基线,目的层孔段单条岩芯基线长度不能低于50m,岩芯在任何位置有磨损导致岩芯无法拼合则基线断。传统地质岩芯钻探对岩芯采取... 算井子地段花岗岩深部环境钻探工程属于国家科研项目,项目要求钻孔所取岩芯必须严丝合缝可拼合,并在岩芯上画基线,目的层孔段单条岩芯基线长度不能低于50m,岩芯在任何位置有磨损导致岩芯无法拼合则基线断。传统地质岩芯钻探对岩芯采取率有相应要求,对岩芯有几处磨损并无严格要求,因此传统钻探施工技术不适用于该项目。必须在传统地质岩芯钻探施工技术的基础上,对钻探施工工艺进行改进,以满足该科研项目对岩芯基线长度的要求。通过对近年来施工该项目的经验总结,从设备、操作技术等方面着手进行了技术改进,现场总结出了一套适用的技术方案。BS22号井目的层404.340~606.755m孔段岩芯的平均基线长度为67.472m,最长基线长度达到了111.505m,解决了施工该项目的钻探技术难题。 展开更多
关键词 花岗岩 岩芯 拼合性 基线长度 清水介质 岩粉
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Chip Flood (vs) Core Flood——Assessment of Flowback and Oil Productivity in Oil-Wet Hydraulic Fractured Rocks 预览
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作者 Srikanth Tangirala James J. Sheng Jiawei Tu 《长江油气(英文版)》 2019年第1期59-78,共20页
New developments in lab technologies help us to explore problems that were less understood in the past due to the limitations and technological constraints. One such problem of assessing the formation damage created b... New developments in lab technologies help us to explore problems that were less understood in the past due to the limitations and technological constraints. One such problem of assessing the formation damage created by the invasion of fracture fluid into the matrix at lab scale is the visualization of fluid saturation distributions inside the matrix. According to the current understanding, the high capillarity contrast between the fracture and the matrix creates a non-uniform saturation distribution of invaded fluid phase during flowback, with the saturations mostly concentrated at the fracture face. With the advent of microfluidics, their application has become more feasible to visually analyze the effectiveness of surfactants to mitigate the invasion-created formation damage and understand the impact of depth of invasion on the characteristics of flowback and oil productivity. Through our previous work, we have successfully demonstrated the capability of this new visualization tool in studying the factors of the presence of surfactant in the fracture fluid and its depth of invasion, to understand the flowback efficiencies and later oil productivities in oil-wet fractured formations. Since the substrate for flooding was a proxy model of an actual rock, the chip flooding results need to be validated with conventional core flooding experiments. In contemporary times, when the new advancements in technology are driving the research progress in all industries, it is mandatory to take a well informed decision by imposing a comparative check on the results with accessible conventional means, wherever possible. The success of validation of chip flooding approach with the core flooding approach in this work instates a strong belief over the application of microfluidics to pursue more research in related fields of oil recovery. 展开更多
关键词 CHIP FLOODING CORE FLOODING Flowback Fracture SURFACTANT
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水溶蜡型芯在精密铸造中的应用
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作者 谭培松 《特种铸造及有色合金》 CAS 北大核心 2019年第1期57-59,共3页
针对内腔结构比较复杂、模具无法抽芯的产品,采用水溶蜡代替尿素制作可溶性型芯进行蜡模制作。水溶蜡可溶性型芯具有外表光滑、强度高,收缩小,尺寸稳定、无气味、环保等特点,能够满足内腔结构复杂产品的制作要求。
关键词 水溶蜡 型芯 精密铸造
课堂教学民主的内核、结构及其实践张力 预览
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作者 姜丽华 《现代教育科学》 2019年第3期96-99,105共5页
课堂教学民主是教育民主在实践中的一种具体体现,也是当前教育教学改革所推崇的重要价值主张。然而,在力图体现多样的民主的中小学教学实践中,却或多或少地存在着对课堂教学民主误读、误用的现象,从而导致教学民主实践流于形式或走向放... 课堂教学民主是教育民主在实践中的一种具体体现,也是当前教育教学改革所推崇的重要价值主张。然而,在力图体现多样的民主的中小学教学实践中,却或多或少地存在着对课堂教学民主误读、误用的现象,从而导致教学民主实践流于形式或走向放任。基于此,有必要澄清课堂教学民主的合理内核及其特殊性,并对教学民主在实践中如何保持有效的张力进行剖析。 展开更多
关键词 课堂教学民主 内核 结构 张力
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