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The rock breaking and ROP increase mechanisms for single-tooth torsional impact cutting using DEM 被引量:9
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作者 Xiao-Hua Zhu Yun-Xu Luo Wei-ji Liu 《Petroleum Science》 SCIE CAS CSCD 2019年第5期1134-1147,共14页
Torsional impact drilling is a new technology which has the advantages of high rock-breaking efficiency and a high rate of penetration(ROP).So far,there is no in-depth understanding of the rock-breaking mechanism for ... Torsional impact drilling is a new technology which has the advantages of high rock-breaking efficiency and a high rate of penetration(ROP).So far,there is no in-depth understanding of the rock-breaking mechanism for the ROP increase from torsional impact tools.Therefore,it has practical engineering significance to study the rock-breaking mechanism of torsional impact.In this paper,discrete element method(DEM)software(PFC2 D)is used to compare granite breaking under the steady and torsional impacting conditions.Meanwhile,the energy consumption to break rock,microscopic crushing process and chip characteristics as well as the relationship among these three factors for granite under different impacting frequencies and amplitudes are discussed.It is found that the average cutting force is smaller in the case of torsional impact cutting(TIC)than that in the case of steady loading.The mechanical specific energy(MSE)and the ratio of brittle energy consumption to total energy are negatively correlated;rock-breaking efficiency is related to the mode of action between the cutting tooth and rock.Furthermore,the ROP increase mechanism of torsional impact drilling technology is that the ratio of brittle energy consumption under the TIC condition is larger than that under a steady load;the degree of repeated fragmentation of rock chips under the TIC condition is lower than that under the steady load,and the TIC load promotes the formation of a transverse cracking network near the free surface and inhibits the formation of a deep longitudinal cracking network. 展开更多
关键词 Torsional impact rock breaking mechanical specific energy Fractal dimension MICROCRACK DEM
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Analysis of main roof breaking form and its mechanism during first weightingin longwall face 被引量:1
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作者 黄庆享 《Journal of Coal Science & Engineering(China)》 2001年第1期9-12,共4页
By field observation and simulating test in shallow seam longwall mining, the asymmetry breaking of main roof is discovered during the first weighting. Based on simulating model test and theoretical analysis, the mech... By field observation and simulating test in shallow seam longwall mining, the asymmetry breaking of main roof is discovered during the first weighting. Based on simulating model test and theoretical analysis, the mechanism of main roof first breaking is revealed, and the asymmetry breaking parameter is determined at all. 展开更多
关键词 main roof first breaking asymmetry mechanism
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Study on Dormancy Mechanism and Breaking Dormancy Method of <i>Viburnum sargentii</i>Seeds
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作者 Qian Zhang Ying Li +3 位作者 Xia Sun Shiyan Xing Wei Cong Xuejun Liu 《American Journal of Plant Sciences》 2019年第1期65-78,共14页
Under untreated conditions, the germination rate of Viburnum sargentii seeds is very low. By exploring the relationship between the dynamic changes of physicochemical indicators and endogenous hormones and seed germin... Under untreated conditions, the germination rate of Viburnum sargentii seeds is very low. By exploring the relationship between the dynamic changes of physicochemical indicators and endogenous hormones and seed germination during the dormancy and germination of Viburnum sargentii seeds, the mechanism of seed germination of Viburnum sargentii was determined, which provided a theoretical basis for its extensive promotion and development. The contents of soluble sugar and soluble starch were determined by anthrone colorimetry. The soluble protein was determined by Coomassie brilliant blue G-250 staining. The activity of polyphenol oxidase (PPO) was determined by NBT reduction method. The peroxidase (POD) was determined by guaiacol method. And the endogenous hormones ZA, IAA, ABA, GA3 were determined by liquid chromatography. Results show: 1) Under natural conditions, the seeds of Viburnum sargentii are difficult to germinate. 2) Under sand storage for 8 months, the germination rate of untreated seeds was 33%. Puncture and peeling treatment could significantly increase the germination rate, and the germination rate of seeds treated with puncture was 92%, and that treated with peel was 98%. 3) Seed germination was accompanied by the decrease in macromolecular substances such as soluble sugar, soluble starch, and soluble protein. 4) The dynamic changes of hormones during seed germination conform to the hypothesis of “three factors”. 5) The treatment of puncture and peeling increased the content of endogenous hormones promoting germination, decreased the endogenous hormones inhibiting seed germination, and increased the ratio of (IAA + GA + ZR)/ABA or GA/ABA. The seeds of Viburnum sargentii have obvious dormancy characteristics. Under the condition of sand storage, both pricking and peeling treatment can effectively promote the process of breaking dormancy, and the effect of peeling treatment is better. 展开更多
关键词 VIBURNUM sargentii DORMANCY mechanism ENDOGENOUS HORMONES breaking DORMANCY
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In-site core disking phenomenon and break mechanism of hard marble:Investigation in 2400 m deep-buried underground laboratory 被引量:7
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作者 ZHONG Shan JIANG Quan +4 位作者 LIU Chang LI Shao-jun QIN Wei-min ZHOU Ji-fang SUN Wen-liang 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第10期2959-2970,共12页
The core-disk phenomenon has been observed generally in the drilling process under high-stress conditions.This paper presents the in-situ experimental study of the coring-disking failure mechanism of marble in an unde... The core-disk phenomenon has been observed generally in the drilling process under high-stress conditions.This paper presents the in-situ experimental study of the coring-disking failure mechanism of marble in an underground cavens with 2400 m depth.Based on the disk samples in several boreholes with different diameters,both macro-and micro-morphological characteristics of core-disks’break surface were analysis,using 3D optical scanning and electron microscope scanning.Moreover,the numerical back analysis was also used to simulate the drilling process for demonstrating the development of core disking.The in-situ experiment results showed that the failure types of core disking consisted of tensile break and shear break,i.e.,the shear break usually appears in the edge part of break surface,and tensile break appears in the central part.What’s more,the ration of core-disks thickness to borehole diameter is in a relatively stable range.Numerical back analysis indicated this micro asynchronous break of hard marble is induced by high geostress and unloading drill. 展开更多
关键词 rock mechanics deep engineering shear break tensile break high geostress
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Analysis of seismic disaster failure mechanism and dam-break simulation of high arch dam 被引量:2
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作者 Zhang Jingkui Zhang Liaojun 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2014年第2期327-335,共9页
Based on a Chinese national high arch dam located in a meizoseismal region, a nonlinear numerical analysis model of the damage and failure process of a dam-foundation system is established by employing a 3-D deformabl... Based on a Chinese national high arch dam located in a meizoseismal region, a nonlinear numerical analysis model of the damage and failure process of a dam-foundation system is established by employing a 3-D deformable distinct element code(3DEC) and its re-development functions. The proposed analysis model considers the dam-foundation-reservoir coupling effect, infl uence of nonlinear contact in the opening and closing of the dam seam surface and abutment rock joints during strong earthquakes, and radiation damping of far fi eld energy dissipation according to the actual workability state of an arch dam. A safety assessment method and safety evaluation criteria is developed to better understand the arch dam system disaster process from local damage to ultimate failure. The dynamic characteristics, disaster mechanism, limit bearing capacity and the entire failure process of a high arch dam under a strong earthquake are then analyzed. Further, the seismic safety of the arch dam is evaluated according to the proposed evaluation criteria and safety assessment method. As a result, some useful conclusions are obtained for some aspects of the disaster mechanism and failure process of an arch dam. The analysis method and conclusions may be useful in engineering practice. 展开更多
关键词 high arch dam complex foundation 3DEC disaster mechanism dam-break process simulation seismic safety evaluation
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Experimental research and energy analysis of a new type of dry ice powder pneumatic rock breaking technology 被引量:2
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作者 Xiaofei Wang Shaobin Hu +2 位作者 Enyuan Wang Qiang Zhang Bing Liu 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2023年第4期423-435,共13页
When the traditional drill and blast method is applied to rock crushing projects,it has strong vibration,loud noise and dust pollution,so it cannot be used in densely populated areas such as urban public works.We deve... When the traditional drill and blast method is applied to rock crushing projects,it has strong vibration,loud noise and dust pollution,so it cannot be used in densely populated areas such as urban public works.We developed a supercritical CO_(2)true triaxial pneumatic rock-breaking experimental system,and conducted laboratory and field tests of dry ice powder pneumatic rock-breaking.The characteristics of the blast-induced vibration velocity waveform and the evolution of the vibration velocity and frequency with the focal distance were analyzed and discussed.The fracturing mechanism of dry ice powder pneumatic rock breaking is studied.The research results show that:(1)The vibration velocity induced by dry ice powder pneumatic rock breaking decays as a power function with the increase of the focal distance;(2)The vibration frequency caused by dry ice powder pneumatic rock breaking is mainly distributed in 1–120 Hz.Due to the dispersion effect,the dominant frequency of 10–30 Hz appears abnormally attenuated;(3)The traditional CO_(2)phase change fracturing energy calculation formula is also applicable to dry ice pneumatic rock breaking technology,and the trinitrotoluene(TNT)equivalent of fracturing energy is applicable to the Sadovsky formula;(4)Dry ice powder pneumatic rock breaking is shock wave and highenergy gas acting together to fracture rock,which can be divided into three stages,among which the gas wedge action of high-energy gas plays a dominant role in rock mass damage. 展开更多
关键词 Dry ice powder pneumatic rock breaking Cracking mechanism Energy analysis Vibration frequency
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Investigation of earthquake mechanisms and their impact on certain basic concepts in earthquake engineering and seismology
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作者 Men Fulu 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2002年第2期281-291,共11页
In this paper, mantle circulation flow, continental drift, earthquake origin and other mechanical principles are examined as they apply to earthquake engineering, seismology and dynamics of fluid saturated porous medi... In this paper, mantle circulation flow, continental drift, earthquake origin and other mechanical principles are examined as they apply to earthquake engineering, seismology and dynamics of fluid saturated porous medium. The relationship of mantle flow to earthquakes is examined and clarified, and a new model, different from Haskell’s, is proposed for the earthquake mechanism. The proposed new model is based on the discovery that two pairs of jump stress and jump velocity will start to act from the fault plane. Records obtained directly from recent earthquakes nearby and right on the fault break show a very large velocity impulse, which verify, indirectly, the new mechanism proposed by the author. Further, at least two physical parameters that characterize the seismic intensity must be specified, because according to the discontinuous (jump) wave theory, at the earthquake source, the stress jump and the velocity jump of particle motion should act simultaneously when a sudden break occurs. The third key parameter is shown to be the break (fracture) propagation speed together with the break plane area. This parameter influences the form of the unloading time function at the source. The maximum seismic stress in and displacement of a building are estimated for two unfavorable combinations of the building and its base ground in terms of their relative rigidity. Finally, it is shown that Biot’s theory of wave propagation in fluid saturated porous media is valid only when fluid flow cannot occur. 展开更多
关键词 mantle circulation flow plate motion earthquake mechanism wave propagation break (fracture) propagation unloading wave jump wave building Biot’s theory
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Electrical arc contour cutting based on a compound arc breaking mechanism 被引量:3
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作者 Guo-Jian He Lin Gu +3 位作者 Ying-Mou Zhu Ji-Peng Chen Wan-Sheng Zhao K.P.Rajurkar 《Advances in Manufacturing》 SCIE EI CAS CSCD 2022年第4期583-595,共13页
Electrical arc contour cutting(EACC)is a novel high-efficiency material cutting process that applies arc plasma to perform efficient and economical contour cutting of difficult-to-cut materials.Compared to conventiona... Electrical arc contour cutting(EACC)is a novel high-efficiency material cutting process that applies arc plasma to perform efficient and economical contour cutting of difficult-to-cut materials.Compared to conventional electrical arc machining(EAM),this process can remove the allowance of open structures and plates in bulk mode,rather than entirely in the form of debris.Compared with existing contour cutting methods,EACC possesses the advantages of high cutting efficiency and a deep cutting depth.Particularly,a compound arc breaking mechanism(CABM),which integrates hydrodynamic force and mechanical motion,has been applied to control the discharge arc column in EACC,while also strengthening the debris expelling effect in the narrow discharge gap.The CABM implementation conditions were studied,based on arc column distortion images captured by a high-speed camera and simulation results of the flow field and debris distribution.A set of machining experiments was designed and conducted to optimize the performance of the proposed process.Finally,a SiC_(p)/Al metal matrix composite(MMC)space station workpiece was machined to verify the feasibility and efficiency of this process. 展开更多
关键词 Electrical arc contour cutting(EACC) Electrical arc machining(EAM) Compound arc breaking mechanism(CABM) SiC_(p)/Al metal matrix composite(MMC) High efficiency
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巴旦木分级破壳机设计与试验 被引量:1
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作者 刘旋峰 周欣 +3 位作者 张丽 杨会民 张海春 蒋永新 《干旱地区农业研究》 CSCD 北大核心 2024年第1期278-286,共9页
为解决巴旦木破壳机械生产效率低、破壳率低和核仁损伤量大等问题,通过研究坚果破壳原理,选用适宜机械加工的大巴旦木(‘莎车3号’)为研究对象,设计了巴旦木分级破壳机,同时进行巴旦木尺寸、破壳力加载方向及加载速度、巴旦木含水率的... 为解决巴旦木破壳机械生产效率低、破壳率低和核仁损伤量大等问题,通过研究坚果破壳原理,选用适宜机械加工的大巴旦木(‘莎车3号’)为研究对象,设计了巴旦木分级破壳机,同时进行巴旦木尺寸、破壳力加载方向及加载速度、巴旦木含水率的物料特性分析。结果表明:破壳机破壳辊间隙和含水率对巴旦木破壳力和变形量影响显著。使用试验法优化了巴旦木分级破壳机构工作参数,当两轧辊间距离调整为Ⅰ级14 mm、Ⅱ级13 mm和Ⅲ级12 mm,含水率控制在9.8%~10.5%范围内,转速为1 000 r·min^(-1)时,测得平均破壳率为95.57%,平均破损率为3.37%,满足实际生产需求。 展开更多
关键词 巴旦木 分级破壳 力学特性 破壳率 破损率
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冲击破岩钻井提速技术研究现状与发展建议 被引量:4
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作者 李根生 穆总结 +2 位作者 田守嶒 黄中伟 孙照伟 《新疆石油天然气》 CAS 2024年第1期1-12,共12页
提高钻井速度不仅是提高我国油气效益开发及深地勘探等方面的重要技术手段,同时对保障国家能源安全意义重大。冲击破岩钻井技术在国内外油田现场应用并获得了良好的提速效果,持续开展此类技术攻关有望攻克当下我国深地高温高压硬岩地层... 提高钻井速度不仅是提高我国油气效益开发及深地勘探等方面的重要技术手段,同时对保障国家能源安全意义重大。冲击破岩钻井技术在国内外油田现场应用并获得了良好的提速效果,持续开展此类技术攻关有望攻克当下我国深地高温高压硬岩地层进尺低、提速难的技术痛点。介绍和分析了轴向冲击、扭力冲击和轴-扭耦合冲击辅助钻头破岩钻进技术方面的实践及发展动态。结合冲击破岩钻井技术现状,阐明了冲击辅助钻头破岩力学原理是冲击破岩钻井提速技术的关键问题,综述了国内外研究学者在冲击辅助钻头破岩物理实验、理论模型和数值模拟等研究方法上取得的科学进展。针对冲击破岩钻井提速技术的发展提出了相关建议,即加强在材料结构优化设计、智能化控制、多元技术融合和井场应用优化等方面的研究力度,为我国能源高效开发做出贡献。 展开更多
关键词 钻井 提速 冲击钻井 技术现状 破岩原理 发展建议
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凸棱非平面聚晶金刚石齿的破岩机理及在含砾地层中的应用 被引量:1
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作者 陈炼 魏小虎 +5 位作者 曹强 周岩 杨迎新 胡川 赵志杰 伍彬 《中国机械工程》 EI CAS CSCD 北大核心 2024年第2期371-379,共9页
为提高聚晶金刚石复合片(PDC)钻头在含砾、软硬交错等不均质地层中的抗冲击性能,开展了凸棱非平面PDC齿的研究。通过仿真和室内实验对比分析了凸棱非平面齿与常规平面齿的破岩机理。与平面齿相比,凸棱非平面齿与岩石的接触应力分布更均... 为提高聚晶金刚石复合片(PDC)钻头在含砾、软硬交错等不均质地层中的抗冲击性能,开展了凸棱非平面PDC齿的研究。通过仿真和室内实验对比分析了凸棱非平面齿与常规平面齿的破岩机理。与平面齿相比,凸棱非平面齿与岩石的接触应力分布更均匀,切削破岩过程中的载荷波动幅度明显更小,切削稳定性更高。凸棱齿特殊的非平面结构改变了切削齿与岩石的互作用方式,在不均质地层得到成功应用。 展开更多
关键词 非平面聚晶金刚石齿 含砾地层 破岩机理 冲击损坏
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冻结立井井筒机械化掘进现状及发展趋势
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作者 陈湘生 王恒 +4 位作者 宋朝阳 陈汉青 陈曦 丁航 王磊 《煤炭科学技术》 EI CAS CSCD 北大核心 2024年第9期1-17,共17页
针对我国“富煤贫油少气”的能源赋存结构及煤炭未来一段时间将长期占据能源消耗主导地位的特点,回顾了我国煤炭井工开采领域冻结立井井筒机械化掘进发展历程。钻爆法凿井作为我国立井井筒施工的主要工法,炸药的应用大幅提高了冻结井筒... 针对我国“富煤贫油少气”的能源赋存结构及煤炭未来一段时间将长期占据能源消耗主导地位的特点,回顾了我国煤炭井工开采领域冻结立井井筒机械化掘进发展历程。钻爆法凿井作为我国立井井筒施工的主要工法,炸药的应用大幅提高了冻结井筒的掘进效率,配套的伞钻打孔、抓岩机装岩、大型井架及设备提升、大模板砌壁等大型机械化设备的应用,大幅提高了井筒成井速度;竖井钻机、反井钻机及竖井掘进机作为特殊地层条件下立井井筒特殊凿井方式,也有各自应用范围。面对我国西部富水弱胶结地层特点及智慧矿山发展趋势,采用冻结+钻爆法施工难以满足千米级弱胶结岩层立井井筒智能化无人化的建设需求,而采用冻结+竖井掘进机钻井是未来超深立井井筒技术发展方向之一。结合国外冻结+竖井掘进机凿井工程案例,针对我国西部富水弱胶结岩层立井井筒建设,提出了冻结+竖井掘进机凿井在冻结壁厚度和强度设计理论、双层钢筋混凝土井壁永久支护、低温环境下竖井掘进机掘进破岩形式以及分级上排渣方式等冻-掘-支-运协同作业方面提出了合理化建议;明确了井壁结构与弱胶结围岩相互作用机理,优化双层井壁结构方法,构建竖井掘进机掘-支-运同步作业模式等,提升井筒建设综合效率,提高信息化水平,推动立井井筒向机械化、绿色化和智能化发展。 展开更多
关键词 特殊凿井 机械破岩 冻结井壁 竖井掘进机
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金属矿山深部硬岩矿床非爆连续采矿技术及应用
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作者 刘福春 郭钦鹏 熊有为 《有色金属(矿山部分)》 2024年第6期64-69,83,共7页
随着我国矿产资源需求的不断攀升及浅层矿产资源的日益枯竭,向深部拓展开采新的矿产资源已成为必然的趋势。首先,针对传统的凿岩爆破工艺在深部开采中面临的诸多挑战,阐述了深部硬岩矿床非爆连续采矿技术及装备。然后,以某深部硬岩矿山... 随着我国矿产资源需求的不断攀升及浅层矿产资源的日益枯竭,向深部拓展开采新的矿产资源已成为必然的趋势。首先,针对传统的凿岩爆破工艺在深部开采中面临的诸多挑战,阐述了深部硬岩矿床非爆连续采矿技术及装备。然后,以某深部硬岩矿山为例,详细介绍了非爆连续采矿技术的应用实践,并展示了所带来的积极成效,为深部硬岩矿床非爆连续开采提供案例借鉴;最后,基于实践经验,结合人工智能等前沿技术,提出了矿石制浆与水力输送技术,有望为深井矿石的提升提供一种更为高效、环保的解决方案,进一步优化和提升深部矿山的开采效率和安全性。 展开更多
关键词 深部开采 硬岩矿床 综合机械化掘进 机械破岩 水力输送
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岩体弱化方法及其在深部高应力硬岩机械化开采中的应用
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作者 李夕兵 郭懿德 +1 位作者 陈江湛 黄麟淇 《有色金属(矿山部分)》 2024年第6期51-63,共13页
战略性矿产资源的安全保供是国家重大战略需求,向地球深部要矿产资源在未来相当长一段时间内具有不可替代的战略性。为了保障矿产资源需求,深部高应力硬岩的安全高效开采是深部采矿必须解决的重大问题。首先,本文阐述了深部高应力硬岩... 战略性矿产资源的安全保供是国家重大战略需求,向地球深部要矿产资源在未来相当长一段时间内具有不可替代的战略性。为了保障矿产资源需求,深部高应力硬岩的安全高效开采是深部采矿必须解决的重大问题。首先,本文阐述了深部高应力硬岩采矿的技术挑战及“变害为利”的采矿变革思路,提出了高应力硬岩弱化后再开展机械破岩以实现商业化开采的关键技术对策。然后,总结了“接触式”和“非接触式”岩体弱化方法的机理、具体特点与发展现状,并对比分析了两类岩体弱化方法在辅助高应力硬岩机械破岩领域的发展潜力。最后,展望了以深部高应力硬岩热剥落损伤弱化辅助机械破岩为代表的安全高效连续采矿技术,为深部战略性矿产资源安全保供与深地工程发展提供了有益指导。 展开更多
关键词 深部矿产 动静组合加载 高应力硬岩 岩体弱化 机械破岩 岩石破裂
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一种新型四孔异形蜂窝包装夹层结构力学性能研究
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作者 冯砚博 于太航 于润泽 《包装工程》 CAS 北大核心 2024年第13期79-88,共10页
目的随着新材料和新结构的发展,包装材料结构要求在包装运输过程中对产品具有更高的保护能力。为了丰富包装材料结构并在保证力学性能条件下设计新型蜂窝结构。方法以传统正六边形蜂窝结构为基础构建新型四孔异形蜂窝结构,通过对可降解... 目的随着新材料和新结构的发展,包装材料结构要求在包装运输过程中对产品具有更高的保护能力。为了丰富包装材料结构并在保证力学性能条件下设计新型蜂窝结构。方法以传统正六边形蜂窝结构为基础构建新型四孔异形蜂窝结构,通过对可降解树脂材料的试件进行理论分析、仿真分析和实验验证研究其力学特性。结果新型四孔异形蜂窝包装夹层结构横向和纵向的力学性能,相较于传统的正六边形和正八边形蜂窝结构提升了17%,具有更好的外载荷承载能力。结论本研究对包装材料结构给出了新的思路,对包装行业的发展起到支持作用。 展开更多
关键词 新型蜂窝结构 可降解树脂材料 包装夹层结构 力学性能 断裂应力
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考虑多场耦合高压电脉冲作用下岩体破碎响应
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作者 饶平平 冯伟康 +1 位作者 崔纪飞 欧阳昢晧 《工程科学与技术》 EI CAS CSCD 北大核心 2024年第6期93-102,共10页
基于电学理论、热学理论和力学理论建立高压电脉冲作用下岩体破碎多物理场耦合数值模型,提出一种考虑电击穿的电–热–力耦合数值模型揭示岩体在高压电脉冲下的破碎过程。利用随机分布模型模拟岩体中可能出现的导体矿物颗粒,综合分析电... 基于电学理论、热学理论和力学理论建立高压电脉冲作用下岩体破碎多物理场耦合数值模型,提出一种考虑电击穿的电–热–力耦合数值模型揭示岩体在高压电脉冲下的破碎过程。利用随机分布模型模拟岩体中可能出现的导体矿物颗粒,综合分析电击穿过程中等离子体通道的形成规律。与现场试验进行对比,验证该数值模型的准确性。计算结果表明:击穿场强是主导等离子体通道形成的关键因素。岩体在高压电脉冲作用下的破碎过程可分为3个阶段,等离子体通道初步形成阶段、等离子体通道扩展阶段和等离子体通道形成阶段。在等离子体通道形成前,通道处的温度保持在500 K左右,应力达到10–2MPa左右;当等离子体通道形成时,温度和应力会在短时间内剧增,温度达到10~3 K,应力达到10 MPa。在电脉冲持续作用下,等离子体通道处的温度和应力持续增加。当最大应力超过岩体的临界应力强度后,岩体将发生破碎;同时通道也会继续分支扩展,更大范围地对岩体造成破坏。导体矿物颗粒会引导等离子体通道的形成,颗粒分布越密,对通道的形成越有利。脉冲电压到达峰值的时间越长,岩体的破坏速率相对越快。数值模型的计算结果有助于加深对高压电脉冲过程中岩体破碎过程的理解。 展开更多
关键词 高压电脉冲 电–热–力耦合 导体矿物颗粒 等离子体通道 岩体破碎
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基于破血逐瘀理论探讨中药水蛭及其复方治疗肿瘤的研究进展 被引量:2
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作者 谢兴文 王小强 +7 位作者 徐世红 李楷 赵军 李鼎鹏 刘佳 丁聚贤 柳博 姜朝阳 《中华中医药学刊》 CAS 北大核心 2024年第3期1-4,共4页
肿瘤是临床中比较难治疗的疾病,化疗药物的耐药性以及治疗过程中的不良反应增加了治疗的难度。中药作为天然药物,具有不良反应少、遗传毒性低等优点,可以在治疗肿瘤疾病的同时对机体功能从根本上进行调理,通过查阅文献发现破血逐瘀药物... 肿瘤是临床中比较难治疗的疾病,化疗药物的耐药性以及治疗过程中的不良反应增加了治疗的难度。中药作为天然药物,具有不良反应少、遗传毒性低等优点,可以在治疗肿瘤疾病的同时对机体功能从根本上进行调理,通过查阅文献发现破血逐瘀药物,如三棱、莪术、水蛭、斑蝥等用于治疗肿瘤疗效确切,基于此,从破血逐瘀理论出发,分析肿瘤的中医病因病机及破血逐瘀治则,总结水蛭临床治疗肿瘤的部分作用机制,旨在为临床诊疗该疾病提供参考及研究方向。 展开更多
关键词 破血逐瘀 肿瘤 水蛭 带瘤生存 作用机制
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旋冲钻井技术研究现状与展望 被引量:1
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作者 张诗达 朱勇 +1 位作者 高强 苏红 《排灌机械工程学报》 CSCD 北大核心 2024年第5期497-507,共11页
随着中国资源勘探开发面向深层、超深层发展以及对应急钻孔救援水平保障能力的更高需求,旋冲钻井技术成为高效钻井领域的研究热点.旋冲钻井技术相较于传统旋转钻井技术,具备硬岩地层钻进效率高、钻压调控灵活、黏滑振动强度低等优势,广... 随着中国资源勘探开发面向深层、超深层发展以及对应急钻孔救援水平保障能力的更高需求,旋冲钻井技术成为高效钻井领域的研究热点.旋冲钻井技术相较于传统旋转钻井技术,具备硬岩地层钻进效率高、钻压调控灵活、黏滑振动强度低等优势,广泛应用于深海深地资源勘探开采、应急钻孔救援等领域,具有广阔的应用前景.现阶段,在复杂岩层以及多变工况等条件下,进一步提高旋冲钻进效率、降低成本成为深井、超深井钻井过程中面临的首要任务.文中首先介绍了旋冲钻井技术的基本概念及优势;其次,综述了液动和气动2种冲击器的研制情况及结构特点;再次,讨论了高效破岩机制的研究进展和优化策略;从次,阐述了钻进效率关键影响因素方面的研究成果;最后,基于旋冲钻井技术研究成果和面临的挑战,对其未来研究方向进行了分析和展望. 展开更多
关键词 旋冲钻井 动力方式 钻进效率 破岩机理 高效破岩
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五宝场硬塑性地层斧形曲面PDC齿破岩性能研究 被引量:2
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作者 荣准 杨学军 +3 位作者 张航 颜爽 张琦 张龙龙 《钻探工程》 2024年第2期85-93,共9页
为解决川东油气钻井中五宝场沙溪庙组硬塑性地层PDC钻头磨损严重、起下钻频繁的问题,开展了斧形曲面PDC齿在硬塑性地层破岩性能的研究。首先采用X射线衍射试验与三轴力学试验分别获取该地层岩石性质和力学参数,然后采用有限元仿真与试... 为解决川东油气钻井中五宝场沙溪庙组硬塑性地层PDC钻头磨损严重、起下钻频繁的问题,开展了斧形曲面PDC齿在硬塑性地层破岩性能的研究。首先采用X射线衍射试验与三轴力学试验分别获取该地层岩石性质和力学参数,然后采用有限元仿真与试验相结合的方法开展斧形曲面PDC齿破岩性能研究。研究结果表明:斧形曲面PDC齿主要以剪切、挤压、犁切共同作用破岩;相较于常规PDC齿,斧形曲面PDC齿有更强的吃入岩石的能力和稳定性,能有效减小钻头异常振动,提高钻头寿命,并在不同磨损高度(0~3 mm)时,破岩比功降低2.2%~8.2%;根据试验得到斧形曲面齿较常规齿破岩性能提高了11.39%,且试验与仿真平均切削力误差仅为7.46%,验证了仿真模型的正确性。本研究表明斧形曲面PDC齿在硬塑性地层对提高破岩性能具有重要意义。 展开更多
关键词 斧形曲面PDC齿 硬塑性地层 破岩比功 磨损高度 破岩性能
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榛子破壳力学特性分析与试验研究
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作者 鞠鑫林 滕美茹 +4 位作者 连政国 何晓宁 尚书旗 时延鑫 高秀强 《农机化研究》 北大核心 2024年第12期174-178,共5页
为了解决榛子破壳效率低的问题,针对榛子破壳所需的各项参数设计了一组正交试验。以榛子尺寸、加载速度、加载方向为试验因素进行三因素三水平试验,试验指标为整仁率与破壳力。结果表明:对榛子破壳力影响最显著的因素是榛子尺寸,其次为... 为了解决榛子破壳效率低的问题,针对榛子破壳所需的各项参数设计了一组正交试验。以榛子尺寸、加载速度、加载方向为试验因素进行三因素三水平试验,试验指标为整仁率与破壳力。结果表明:对榛子破壳力影响最显著的因素是榛子尺寸,其次为加载方向且沿宽度向加载时所需力最小,加载速度对于破壳力的影响较小。榛子高度向、宽度向、厚度向的平均破壳力分别为1867.2、1818.6、2326.7N,对榛子破壳整仁率影响最显著的因素是加载方向,其次为加载速度。对榛子3个加载方向使用有限元方法进行分析,得出宽度向为较佳的加载方向,与正交试验的结果一致。在对榛子破壳相关机械进行设计时,施加在榛子上的力应不小于2400N,并尽量使榛子沿宽度向受力。研究结果可为后期榛子破壳相关机械的结构设计提供理论依据。 展开更多
关键词 榛子 破壳 力学特性 有限元分析
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