检索结果-南通市图书馆

建筑工程（中英文版） 2014年第1期2卷 15-19页

作者： Hailei Kou mingyi zhang Institute of Geotechnical Engineering Qingdao Technological University Qingdao 266033 China

植被修复初期对贵州高原喀斯特湿地湖滨带碳元素的影响

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

生态学报 2022年第19期42卷 7785-7795页

作者：吴云杰田鑫张明意王硕贵州民族大学生态环境工程学院/喀斯特湿地生态研究中心贵阳550025

以贵州草海保护区(海拔约为2171.7 m)为研究对象,采用时空互代法研究不同地貌环境(非喀斯特地貌、喀斯特地貌及植被修复地貌)下,保护区内土壤有机碳(SOC)、易氧化有机碳(ROC)、可溶性有机碳(DOC)含量分布规律及其影响因素,以期为准确估... 详细信息

以贵州草海保护区(海拔约为2171.7 m)为研究对象,采用时空互代法研究不同地貌环境(非喀斯特地貌、喀斯特地貌及植被修复地貌)下,保护区内土壤有机碳(SOC)、易氧化有机碳(ROC)、可溶性有机碳(DOC)含量分布规律及其影响因素,以期为准确估算保护区内碳组分储量及其固碳效益评价提供科学依据。结果表明:(1)不同地貌下有机碳(SOC)含量、易氧化有机碳(ROC)和可溶性有机碳(DOC)与土层深度存在极显著负相关关系,即随土层深度增加而降低;(2)在0—50 cm土层中喀斯特地貌与非喀斯特地貌下土壤团聚体均以>0.2 mm粒级有机碳含量相对较高,<0.125 mm粒级含量最低。(3)植被恢复过程中,土壤碳组分含量显著增加,土壤固碳能力增强提高了土壤有机碳含量,促进了土壤团聚体的形成,同时也提高了土壤团聚体的稳定性。

关键词：喀斯特有机碳植被修复草海保护区

在线全文

学校读者我要写书评

暂无评论

泥岩地基打入式预制桩承载力时效性分析

中南大学学报（自然科学版） 2022年第11期53卷 4504-4513页

作者：张亚妹张立秦明光白晓宇闫楠张明义韩超青岛理工大学土木工程学院山东青岛266520 山东省高等学校蓝色经济区工程建设与安全协同创新中心山东青岛266520 惠州大亚湾经济技术开发区工程建设安全监督站广东惠州516083 青岛上合基石投资发展集团有限公司山东青岛266318

以风化泥岩作为桩端持力层的预制桩,沉桩结束一段时间后常出现单桩承载力不足的现象。针对以上问题,依托青岛某实际工程,在锤击沉桩结束后不同休止时间内,开展3根试桩和2根工程桩的单桩竖向抗压静载试验,分析单桩竖向承载力随时间的演... 详细信息

以风化泥岩作为桩端持力层的预制桩,沉桩结束一段时间后常出现单桩承载力不足的现象。针对以上问题,依托青岛某实际工程,在锤击沉桩结束后不同休止时间内,开展3根试桩和2根工程桩的单桩竖向抗压静载试验,分析单桩竖向承载力随时间的演化特征,探究泥岩地基中打入式预制桩单桩承载力与休止时间的关联性。研究结果表明:以强风化泥质粉砂岩为持力层的打入式预制桩,沉桩结束后单桩承载力随休止时间增长而降低,降低幅度为10%,且从沉桩结束到出现承载力降低存在一个滞后期,滞后期为15 d;桩端泥岩遇水发生软化是单桩承载力随成桩时间降低的主要原因,但也有互层等非均质因素的影响;泥岩的水文、力学性质与其矿物成分、胶结类型密切相关,降雨、地下水渗流对泥岩中的泥质胶结特性产生负面效应,弱化泥岩作为持力层的承载能力。

关键词：预制桩锤击沉桩静载试验承载力时效性泥岩

在线全文

学校读者我要写书评

暂无评论

可调壁厚风电混凝土塔筒的模块化设计

特种结构 2022年第6期39卷 39-42+50页

作者：张明熠上海电气风电集团股份有限公司

风电机组大型化迭代的加速对混凝土塔筒提出适配性和经济性的要求。相比传统混凝土塔筒通过调整混凝土强度线性适配塔筒载荷,可调壁厚的混凝土塔筒则可以在强度和壁厚两个维度提供矩阵式的塔筒承载能力适配度。通过模块化设计既满足了... 详细信息

风电机组大型化迭代的加速对混凝土塔筒提出适配性和经济性的要求。相比传统混凝土塔筒通过调整混凝土强度线性适配塔筒载荷,可调壁厚的混凝土塔筒则可以在强度和壁厚两个维度提供矩阵式的塔筒承载能力适配度。通过模块化设计既满足了不同风电机组对塔筒的承载能力、结构频率以及叶尖净空的性能要求,又提高混塔模具的利用率和周转效率。可调壁厚的混塔为风电行业大型化风机塔筒的标准化与批量化打下坚实基础,有利于传统基建行业的过剩产能向新能源行业转型发展,从而为实现“3060双碳目标”提供兼具经济性和实用性的产业发展方向。

关键词：混凝土塔筒风电机组管片模具模块化设计

Numerical analysis for random temperature fields of embankment in cold regions

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2007年第3期50卷 404-410页

作者： LIU ZhiQiang LAI YuanMing zhang mingyi zhang XueFu State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research InstituteChi-nese Academy of SciencesLanzhou 730000China School of Civil Engineering Lanzhou Jiao Tong UniversityLanzhou 730070China Chongqing Jiao Tong University Chongqing 400074China

The stochastic finite element equations for random temperature are obtained using the first-order per-turbation technique taking into account the random thermal properties and boundary condition, based on heat transfer variational principle. The local average method for 2-D is used to discretize random fields. Then, the random temperature fields of embankment in cold regions are investigated on condi-tion that the thermal properties and boundary condition are taken as random fields, respectively, by using the program, which is written by the methods. The expected value of temperature field and the standard deviation of the temperature field of embankment in cold regions are obtained and analyzed.

关键词： frozen soil embankment Qinghai-Tibet railway random temperature field numerical analysis stochastic finite element method

从犹豫到接受:意义建构视角下公众疫苗认知演变路径研究

在线全文

学校读者我要写书评

暂无评论

图书情报工作 2023年第16期67卷 41-51页

作者：张云开李月琳张泰瑞张铭毅南开大学商学院天津300071

[目的/意义]疫苗犹豫一直是阻碍公众完成疫苗接种的主要原因之一。研究聚焦我国公众疫苗犹豫问题,以揭示公众从疫苗犹豫到接受的认知过程及信息搜寻的影响。[方法/路径]以意义建构理论为框架,采用微刻时序(Micro-Moment Time-Line)访谈... 详细信息

[目的/意义]疫苗犹豫一直是阻碍公众完成疫苗接种的主要原因之一。研究聚焦我国公众疫苗犹豫问题,以揭示公众从疫苗犹豫到接受的认知过程及信息搜寻的影响。[方法/路径]以意义建构理论为框架,采用微刻时序(Micro-Moment Time-Line)访谈法收集26名受访者的访谈数据,采用质性数据分析方法分析数据,探究公众从疫苗犹豫到接受的认知演变过程,揭示其意义建构模式。[结果/结论]公众从疫苗犹豫到疫苗接受经历恐惧与排斥、好奇与观望、学习与接受、信任与接纳4个认知演变阶段。公众的疫苗认知演变过程具有动态特征。意义建构的障碍主要包括风险认知、认知偏差、负面经历、生活变化、信息过载以及知识缺失6种类型。同时,信息搜寻类型与搜寻渠道对公众疫苗信息的意义建构过程产生影响。研究结果有助于政府及相关机构开展更有针对性的疫苗教育和疫苗推广政策。

关键词：意义建构理论认知演变疫苗犹豫质性研究微刻时序访谈法

Structure and Migration Characteristic of Heterointerfaces During the Phase Transformation from L1_2 to DO_(22) Phase

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2010年第5期25卷 814-819页

作者：张明义 State Key Laboratory of Solidification Processing Northwestern Polytechnical University

Based on the microscopic phase-field model, the structure and migration characteristic of ordered domain interfaces formed between DO22 and L12 phase are investigated, and the atomistic mechanism of phase transformation from L12 （Ni3Al） to DO22 （Ni3V） in Ni75AlxV25-x alloys are explored, using the simulated microstructure evolution pictures and the occupation probability evolution of alloy elements at the interface. The results show that five kinds of heterointerfaces are formed between DO22 and L12 phase and four of them can migrate during the phase transformation from L12 to DO22 except the interface （002）D//（001）L. The structure of interface （100）D//（200）L and interface （100）D//（200）L·^1/2[001] remain the same before and after migration, while the interface （002）D//（002）L is formed after the migration of interface （002）D//（002）L·^1/2[100] and vice versa. These two kinds of interface appear alternatively. The jump and substitute of atoms selects the optimization way to induce the migration of interface during the phase transformation, and the number of atoms needing to jump during the migration is the least among all of the possible atom jump modes.

关键词： phase transformation ordered domain interface interface migration microscopic phase-field Ni75AlxV25-x alloy

Test Research on Special Sucker Rod for Screw Pump

在线全文

学校读者我要写书评

暂无评论

China Oil & Gas 2006年第4期13卷 35-39页

作者： zhang mingyi Chen Mingzhan Li Zhi Research Institute of Production Engineering PetroChina Daqing Oilfield Company Ltd. Daqing Oilfield Engineering Company Ltd.

According to the statistics of straight thread sucker rods' application in screw pump in Daqing Oilfield before 2000, the proportion of sucker rods' yearly breakaway reached to 41.6%, taking up 70% of the total wells that were checked. Thus it can be seen that the rods breakaway problem was becoming the main barrier restricting screw pump large-scale population and application. Since then, the development work on the special sucker rods for screw pump had been carried on. Through the analysis on the failure position and failure form of the sucker rods', the following conclusions

关键词：螺杆泵抽油杆设计断裂试验研究

Numerical Analysis for Temperature Characteristics of Open Boundary Crushed-rock Embankment on Qinghai-Tibet Railway

在线全文

学校读者我要写书评

暂无评论

工程科学（英文版） 2006年第2期4卷 134-142页

作者： Lai Yuanming zhang mingyi Liu Zhiqing Yu Wenbing State Key Laboratory of Frozen Soil Engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000

At present, in order to protect the stability of permafrost beneath emban kment, the crushed-rock emban kment, as a new type of emban kment structure, has widely been used in the construction of Qinghai-Tibet Railway. Its crushed-rock layer is almost open in tow bilateral boundaries and closed at top and bottom, and air can flow into/out of the ballast layer and crushed-rock layer. Therefore, the convection and transfer heat patterns are very complicated in the ballast layer and crushed-rock layer of the emban kment, which are regarded as porous media. In this paper, based on the wind, temperature and geology conditions of Qinghai-Tibet Plateau, a numerical approach of the unsteady two-dimensional continuity, momentum (non-Darcy flow) and energy equations of heat convection for incompressible fluid in porous media is provide to analyse the velocity and temperature characteristics of the crushed-rock emban kment with different emban kment heights under open boundary condition for the coming 50 years. The calculated results indicate that, due to the influence of the external wind, the convective heat transfer mainly relies on the forced convection in the open crushed-rock emban kment. Even if the air temperature will be warmed up by 2.6℃ in the coming 50 years, it still has a better cooling effect on the underlying soils and a low temperature frozen-soil core is formed in the permafrost below it if the emban kment is constructed in the regions whose present mean annual air temperature is -4.0℃. Furthermore, the cooling effect of high crushed-rock emban kment is better than that of low emban kment. This results from the fact that the wider bottom of high emban kment has a more influence dimension on the underlying frozen soil. However, cardinal winds on Qinghai-Tibet Plateau disturb its convection pattern, so that an asymmetric temperature distribution occurs under high emban kment and it is possible to induce a transverse uneven deformation of emban kment, but no similar situation occurs under low emban kment. This

关键词：青藏铁路开放边界碎石堤防温度特性数值分析

Road map for, and technical challenges of, carbon-nanotube integrated circuit technology

在线全文

学校读者我要写书评

暂无评论

National Science Review 2024年第3期11卷 14-16页

作者： Jia Si Panpan zhang Zhiyong zhang Key Laboratory for the Physics and Chemistry of Nanodevices and Center for Carbon-based Electronics School of Electronics Peking University State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

The past decade has witnessed an explosion of research on carbon-nanotube(CNT) electronics due to their outstanding properties, including an ultrathin body, a high carrier mobility and a high saturation velocity.

关键词： TRANSISTORS