检索结果-南通市图书馆

Research on the solid particle erosion wear of pipe steel for hydraulic fracturing based on experiments and numerical simulations

引用

Petroleum Science 2024年第4期21卷 2779-2792页

作者： Si-Qi Yang Jian-Chun Fan Ming-Tao liu De-Ning li jun-liang li li-Hong Han Jian-jun Wang Shang-Yu Yang Si-Wei Dai Lai-Bin Zhang State Key Laboratory of Oil and Gas Equipment CNPC Tubular Goods Research Institute Key Laboratory of Oil and Gas Safety and Emergency Technology China University of Petroleum Oil Production Technology Research Institute of liaohe Oilfield Company Tianjin Gas Storage Branch PetroChina Dagang Oilfield Company Petroleum Production Engineering Research Institute Daqing Oilfield Company

Erosion wear is a common failure mode in the oil and gas industry. In the hydraulic fracturing, the fracturing pipes are not only in high-pressure working environment, but also suffer from the impact of the high-speed solid particles in the fracturing fluid. Beneath such complex conditions, the vulnerable components of the pipe system are prone to perforation or even burst accidents, which has become one of the most serious risks at the fracturing site. Unfortunately, it is not yet fully understood the erosion mechanism of pipe steel for hydraulic fracturing. Therefore, this article provides a detailed analysis of the erosion behavior of fracturing pipes under complex working conditions based on experiments and numerical simulations. Firstly, we conducted erosion experiments on AISI 4135 steel for fracturing pipes to investigate the erosion characteristics of the material. The effects of impact angle, flow velocity and applied stress on erosion wear were comprehensively considered. Then a particle impact dynamic model of erosion wear was developed based on the experimental parameters, and the evolution process of particle erosion under different impact angles, impact velocities and applied stress was analyzed. By combining the erosion characteristics, the micro-structure of the eroded area, and the micro-mechanics of erosion damage, the erosion mechanism of pipe steel under fracturing conditions was studied in detail for the first time. Under high-pressure operating conditions, it was demonstrated through experiments and numerical simulations that the size of the micro-defects in the eroded area increased as the applied stress increased, resulting in more severe erosion wear of fracturing pipes.

关键词： Erosion wear Applied stress Particle impact dynamics Erosion mechanism

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

基于扰动修改的遗传算法

引用

电脑与信息技术 2024年第3期32卷 27-30页

作者：李俊良三峡大学计算机与信息学院湖北宜昌433000

文章主要探讨了系统论的扰动概念与遗传算法的融合,目标是解决一系列具有不确定性的优化问题。算法模拟了自然界的遗传机制,通过引入随机扰动来模拟不确定性,并在遗传进化过程中逐步提升解决方案的质量。在系统论中,“扰动”指的是对系... 详细信息

文章主要探讨了系统论的扰动概念与遗传算法的融合,目标是解决一系列具有不确定性的优化问题。算法模拟了自然界的遗传机制,通过引入随机扰动来模拟不确定性,并在遗传进化过程中逐步提升解决方案的质量。在系统论中,“扰动”指的是对系统产生影响的外部因素,或者是由系统内部因素引起的偏差。这些扰动可能是随机的,也可能是周期性的。本算法展现出了高度的鲁棒性,即使在目标函数发生变化后,仍能保持良好的性能。因此,该算法可以被视为解决类似优化问题的强大工具。

关键词：进化算法系统论扰动

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

外源施用橙皮苷对甜菜幼苗耐盐性的调控作用研究

引用

中国甜菜糖业 2024年第1期 15-20,48页

作者：赖豪亮李俊良李楠温州大学生命与环境科学学院温州325000

对甜菜根系代谢物的研究发现,盐胁迫显著诱导根中橙皮苷的累积.本研究进一步探究外源施用该化合物对甜菜幼苗耐盐性的影响.研究结果显示,外源橙皮苷削弱了盐胁迫对植株叶绿素含量的功能的损伤、帮助幼苗维持光合作用效率、促进幼苗生物... 详细信息

对甜菜根系代谢物的研究发现,盐胁迫显著诱导根中橙皮苷的累积.本研究进一步探究外源施用该化合物对甜菜幼苗耐盐性的影响.研究结果显示,外源橙皮苷削弱了盐胁迫对植株叶绿素含量的功能的损伤、帮助幼苗维持光合作用效率、促进幼苗生物量增长;此外,添加橙皮苷后幼苗脯氨酸、甜菜碱、可溶性糖的含量升高,POD、SOD、CAT的活性增强.这些生理生化指标的改善极大的提高了甜菜幼苗的耐盐性.本研究证实,橙皮苷可作为一种有效的外源施用化合物,用于提高甜菜幼苗的耐盐性.

关键词：橙皮苷盐胁迫甜菜

来源：

维普期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Changes of ghrelin following oral glucose tolerance test in obese children with insulin resistance

引用

World Journal of Gastroenterology 2008年第12期14卷 1919-1924页

作者： Xiu-Min Wang You-jun Jiang li liang li-Zhong Du Department of endocrinology The Children's Hospital of ZhejiangUniversity School of Medicine 57 Zhugan Xiang Hangzhou310003 Zhejiang Province China

AIM： To characterize changes in ghrelin levels in response to oral glucose tolerance test （OGTT） and to correlate changes in ghrelin levels with changes in insulin and glucose following OGTT in Chinese obese children of Tanner Ⅰ and Ⅱ stage with insulin resistance. METHODS： 22 obese children with insulin resistance state were divided into four groups according to their Tanner stage and gender： boys of Tanner Ⅰ （fir- Ⅰ ）, boys of Tanner Ⅱ（BT-Ⅱ ）, girls of Tanner Ⅰ （GT- Ⅰ ）, girls of Tanner Ⅱ （GT-Ⅱ）. Ghrelin, insulin and glucose were measured at 0, 30, 60 and 120 rain following OGTT. The control children with normal BMI were divided into control boys of Tanner Ⅰ （CBT- Ⅰ, n = 6）, control boys of Tanner Ⅱ （CBT-Ⅱ, n = 5）, control girls of Tanner Ⅰ （CGT- Ⅰ, n = 6）, control girls of Tanner Ⅱ （CGT-Ⅱ, n = 5）. Fasting serum ghrelin levels were analyzed. RESULTS： Ghrelin levels were lower in obese groups. Ghrelin levels of control group decreased in Tanner Ⅱ stage （CGT- Ⅰ vs CGT-Ⅱ t = -4.703, P = 0.001; CBT- Ⅰ vs CBT- Ⅱ t = -4.794, P = 0.001）. Basal ghrelin levels in fir-Ⅱ decreased more significantly than that in BT- Ⅰ group （t = 2.547, P = 0.029）. Ghrelin levels expressed a downward trend after OGTT among obese children. The decrease in ghrelin levels at 60 min with respect to basal values was 56.9% in BT- Ⅰ. Ghrelin concentrations at 0 min correlated directly with glucose level at 0 min in fir- Ⅰ （r = 0.898, P = 0.015）. There wasn＇t a significant correlation of ghrelin changes with glucose changes and insulin changes during OGTT in obese children with insulin resistance. CONCLUSION： In conclusion, in obese children with insulin resistance, ghrelin levels decreased with advancing pubertal stage. Ghrelin secretion suppression following OGTT was influenced by gender and pubertal stage. Baseline ghrelin levels and ghrelin suppression after OGTT did not significantly correlate with the degree of insulin resistance and insulin sensitivity.

关键词： Ghrelin Oral glucose tolerance test Insulinresistance Obese children

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effect and Functional Mechanism of the Action of Exogenous Gibberellin on Flowering of Peach

引用

Agricultural Sciences in China 2008年第11期7卷 1324-1332页

作者： AN li-jun JIN liang YANG Chun-qin li Tian-hong Department of Fruit Science College of Agronomy and Biotechnology China Agricultural University Beijing 100193 P.R. China

This study was conducted to assess the effect of gibberellin and its possible mechanism of action on peach flower formation. At flower induction, 100 mg L^-1 of gibberellic acid 3 （GA3） was sprayed on the leaves of peach [Prunus persica （L.） Batsch.] cv. Bayuecui. Using anatomy, immunohistochemistry, and semi-quantitation, the in situ distribution of GAs and the expression of the key genes involved in peach flower formation in the apical meristem were studied during flowering differentiation. The results showed that induction of flowering in the Bayuecui peach occurred prior to 10 July in Beijing, China. Flower induction and further differentiation of the peach flower organs were significantly inhibited by leaf-spraying of GA3 at a concentration of 100 mg L^-1 during the induction stage. The flowering rate was only 11.67% after treatment. The distribution of GA1 in the apical meristem varied during the process of flower bud differentiation. From 13 june to 25 July, the GA1 signal from control plants was detected mainly in the vascular bundles at the base of the flower buds. No GA1 signal was detected in the apical meristem. After treatment with GA3, the distribution was similar to that of the control from 13 june to 3 July. On 13 July, a GA1 signal was detected in the apical meristem accompanied by an increase in the GA1 signal in the vascular bundles at the base of the flower buds. The GA1 signal weakened significantly in both the vascular bundles and the apical meristem on 25 July. The expression of the genes PpLEAFY and MADS6 in flower buds could be detected only on 10 October in the GA3-treated plants. The critical period for flower induction of Bayuecui peach in Beijing was in early July, during which time, leaf-spraying with 100 mg L-1 GA3 could effectively inhibit flower induction and further differentiation of the flower buds. GA1 in the gibberellin family was the suppressor for flower induction in peach. Its action was affected by the stage of flower bud di

关键词： peach [Prunus persica (L.) Batsch.] gibberellin flowering induction anatomy immunohistochemistry semiquantitation RT-PCR

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Optimal Model Average Prediction in Orthogonal Kriging Models

引用

Journal of Systems Science & Complexity 2024年第3期37卷 1080-1099页

作者： WANG jun HE Jiabei liang Hua li Xinmin School of Mathematics and Statistics Qingdao UniversityQingdao 266071China Department of Statistics George Washington UniversityWashington DC 20052USA

The main objective of this paper is to consider model averaging methods for kriging *** paper proposes a Mallows model averaging procedure for the orthogonal kriging model and demonstrate the asymptotic optimality of the model averaging estimators in terms of mean square *** studies are conducted to evaluate the performance of the proposed method and compare it with the competitors to demonstrate its *** authors also analyse a real dataset for an illustration.

关键词： Asymptotic optimality Mallows criterion optimal model averaging orthogonal kriging model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

过表达甜菜BvALKBH10B基因对拟南芥耐盐性的影响

引用

中国甜菜糖业 2024年第1期 1-5页

作者：王家园陈洁婷李俊良温州大学生命与环境科学学院温州325000

RNA上的m6 A(N6-甲基腺苷)修饰是一种重要的表观遗传修饰,以被证实参与调控植物-环境相互作用,在植物适应环境方面扮演着关键角色.先前的研究初步证实甜菜RNA去甲基化酶基因BvALKBH10B可能在m6A介导的盐胁迫应答过程中发挥重要调控作用... 详细信息

RNA上的m6 A(N6-甲基腺苷)修饰是一种重要的表观遗传修饰,以被证实参与调控植物-环境相互作用,在植物适应环境方面扮演着关键角色.先前的研究初步证实甜菜RNA去甲基化酶基因BvALKBH10B可能在m6A介导的盐胁迫应答过程中发挥重要调控作用.本研究通过构建过表达BvALK-BH10B基因的转基因拟南芥对该基因的耐盐功能进行评估.研究结果有助于更好的理解甜菜耐盐性的表观遗传机制,并为耐盐甜菜品种的改良提供优秀的候选基因.

关键词：甜菜拟南芥 BvALKBH10 B基因盐胁迫

来源：

维普期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Effect of N Fertilization on Grain Yield of Winter Wheat and Apparent N Losses

引用

Pedosphere 2006年第6期16卷 806-812页

作者： CUI Zhen-ling CHEN Xin-Ping li jun-liang XU Jiu-Fei SHI li-Wei ZHANG Fu-Suo College of Resources and Environmental Science China Agricultural University Beijing 100094 （China） Department of Agronomy Laiyang Agricultural College Laiyang 265200 （China）

Excessive nitrogen (N) fertilizer application to winter wheat is a common problem on the North China Plain. To determine the optimum fertilizer N rate for winter wheat production while minimizing N losses, field experiments were conducted for two growing seasons at eight sites, in Huimin County, Shandong Province, from 2001 to 2003. The optimum N rate for maximum grain yield was inversely related to the initial soil mineral N content (Nmin) in the top 90 cm of the soil profile before sowing. There was no yield response to the applied N at the three sites with high initial soil mineral N levels (average 212 kg N ha-1). The average optimum N rate was 96 kg N ha-1 for the five sites with low initial soil Nmin (average 155 kg N ha-1) before sowing. Residual nitrate N in the top 90 cm of the soil profile after harvest increased with increasing fertilizer N application rate. The apparent N losses during the wheat-growing season also increased with increasing N application rate. The average apparent N losses with the optimum N rates were less than 15 kg N ha-1, whereas the farmers' conventional N application rate resulted in losses of more than 100 kg N ha-1. Therefore, optimizing N use for winter wheat considerably reduced N losses to the environment without compromising crop yields.

关键词： apparent N losses,optimum N rate residual soil nitrate N soil mineral N winter wheat yield

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Differential tectonic evolution and formation mechanism of three subsags in Wenchang Sag of Pearl River Mouth Basin,South China Sea

引用

Petroleum Science 2023年第3期20卷 1379-1394页

作者： Qiu-Gen Zheng jun-liang li Bao-Hua Lei Peng Song Qi li De-Feng Shi Hao liu Chang-Song lin School of Ocean Sciences China University of Geosciences(Beijing)Beijing100083China Hainan Branch of the China National Ofshore Oil Corporation HaikouHainan570311China Qingdao Institute of Marine Geology QingdaoShandong266237China Laboratory for Marine Mineral Resources Pilot National Laboratory for Marine Scence and Technoogy(Qingdao)QingdaoShandong26637China

Notable differences in the structural characteristics and evolution of three adjacent sub-sags,i.e.,the Wenchang sub-sags A,B,and C,on the downthrown side of the Zhu Ili South Fault in the Wenchang Sag,are significant as they affect the formation and distribution of the oil and gas in these three ***,the differences in their tectonic evolutions and formation mechanisms have not yet been adequately *** this paper,stress analysis,equilibrium profiles,and paleogeomorphic restora-tion,are used to investigate the dynamic settings,formation mechanisms,and influencing factors of the structural deformation related to the formation of the Wenchang Sag based on interpretation of seismic *** results of the stress analysis suggest clockwise deflection of the regional tensile stress direction from a WNW-ESE trend during the Early Paleocene to NW-SE and NNW-SSE trends during the Eocene,to a nearly N-S trend during the Oligocene,and finally to a NNE-SSW trend during the *** clockwise rotation of the regional tensile stress direction led to the formation of a dextral strike-slip stress component parallel to the NE-trending Zhu I South *** strike-slip stress component formed a releasing bend in sub-sag A,and may be associated with the continuous subsidence of a thick sedimentary layer in sub-sag *** also created a restraining bend in sub-sag B,which underwent multiple structural inversions during its extension and subsidence and has a relatively s mall sedimentary *** double restraining bend in sub-sag C is considered to have been strongly uplifted and eroded in response to this strike-slip stress *** obvious structural inversions in sub-sag B are iden-tified in this *** structural inversions correspond to the last four regional tectonic *** interpretation suggests that the formation of the structural inversions was likely related to the strong tensile stress and the small intersection angle between

关键词： Strike-slip stress Releasing bend Restraining bend Double restraining bend Structura linversion ZhuⅢSouthfault Wenchang sag Northern South China Sea

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Implications of T cell-mediated tumor killing genes for molecular heterogeneity and clinical stratification in lung adenocarcinoma

引用

Genes & Diseases 2024年第4期11卷 39-41页

作者： Tong Qiao Beining Yin jun liang li Wei Department of Thoracic Surgery Henan Provincial People's HospitalZhengzhouHenan 450000China Reproductive Medicine Center The First Affiliated Hospital of Zhengzhou UniversityZhengzhouHenan 450052China Department of Breast Surgery Henan Provincial People's HospitalZhengzhouHenan 450000China

Due to the profound heterogeneity exhibited amongst patients with lung adenocarcinoma(LUAD),considerable variances in clinical efficacy emerge.1 For the aims of precision medicine,a clinical instrument to delineate distinct disease phenotypes and anticipate susceptibility to intervention is *** cytotoxicity mediated through T lymphocytes constitutes a pivotal mechanism of anti-tumoral immunity and the foundation for cancer immunotherapy.?Numerous genes regulating the sensitivity of tumor cells to killing mediated by T lymphocytes(GSTKKs)are conducive to satisfying the aforesaid medical necessity.

关键词： clinical mediated adenocarcinoma

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：