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Theoretical and numerical simulation investigation of deep hole dispersed charge cut blasting

International Journal of Coal Science & Technology 2023年第1期10卷 87-107页

作者： chengxiao li Renshu Yang Yanbing Wang Yiqiang Kang Yuantong Zhang Pin Xie School of Mechanics and Civil Engineering ChinaUniversity of Mining and Technology-BeijingBeijing 100083China School of Civil and Resource Engineering Universityof Science and Technology BeijingBeijing 100083China Gubei Coal Mine of Huaizhe Coal and Electricity Co. LtdHuainan 232150China

Drilling and blasting methods have been used as a common driving technique for shallow-hole driving and blasting in rock roadways.With the advent of digital electronic detonators and the need for increased production efciency,the traditional blasting design is no longer suitable for deep hole blasting.In this paper,a disperse charge cut blasting method was proposed to address the issues of low excavation depth and high block rate in deep hole undercut blasting.First,a blasting model was used to illustrate the mechanism of the deep hole dispersive charge cut blasting process.Then,continuous charge and dispersed charge blasting models were developed using the smooth particle hydrodynamics-fnite element method(SPHFEM).The cutting parameters were determined theoretically,and the cutting efciency was introduced to evaluate the cutting efect.The blasting efects of the two charging models were analyzed utilizing the evolution law of rock damage,the number of rock particles thrown,and the cutting efciency.The results show that using a dispersed charge improves the cutting efciency by about 20%and the rock breakage for the deep hole cut blasting compared to the traditional continuous charge.In addition,important parameters such as cutting hole spacing,cutting hole depth and upper charge proportion also have a signifcant impact on the cutting efect.Finally,the deep hole dispersed charge cut blasting technology is combined with the digital electronic detonator through the feld engineering practice.It provides a reference for the subsequent deep hole cutting blasting and the use of electronic detonators in rock roadways.

关键词： Deep hole blasting Cut blasting Dispersed charge SPH-FEM Digital electronic detonator

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Theoretical and numerical studies of rock breaking mechanism by double disc cutters

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International Journal of Mining Science and Technology 2023年第7期33卷 815-828页

作者： Yiqiang Kang Renshu Yang liyun Yang chengxiao li Jun Chen Haonan Zhu Ning liu School of Mechanics and Civil Engineering China University of Mining and TechnologyBeijing 100083China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China China Coal No.3 Construction(Group)Co. Ltd.Hefei 230000China

A plane mechanical model of rock breaking process by double disc cutter at the center of the cutterhead is established based on contact mechanics to analyze the stress evolution in the rock broken by cutters with different spacings. A continuous-discontinuous coupling numerical method based on zero-thickness cohesive elements is developed to simulate rock breaking using double cutters. The process, mechanism,and characteristics of rock breaking are comprehensively analyzed from five aspects: peak force, breaking form, breaking efficiency, crack mode, and breaking degree. The results show that under the penetrating action of cutters, dense cores are formed due to shear failure under respective cutters. The tensile cracks propagate in the rock, and then rock chips form with increasing penetration depth. When the cutter spacing is increased from 10 to 80 mm, the peak force gradually increases, the rock breaking range increases first and then decreases, the specific energy decreases first and then rises, and the breaking coefficient of intermediate rock decreases from 0.955 to 0.788. The area of rock breaking is positively correlated with the length of the tensile crack. Furthermore, the length of the tensile crack accounts for 14.4%–33.6% of the total crack length.

关键词： Disc cutter spacing Mechanical model Indentation experiment Continuous-discontinuous numerical method Fractal dimension

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Compound-mode crack propagation law of PMMA semicirculararch roadway specimens under impact loading

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International Journal of Coal Science & Technology 2021年第6期8卷 1302-1315页

作者： chengxiao li Dongming Guo Yuantong Zhang Chen An School of Mechanics and Civil Engineering China University of Mining and Technology-BeijingBeijing 100083China

An underground roadway usually contains defects of various types,and when the roadway is subjected to external loading,the locations of those defects influence the roadway by differing degrees.In this study,to study how the locations of defects affect crack propagation in a roadway,specimens with tunnel-type voids were made using polymethyl methacrylate,and the stress wave produced by a bullet impacting an incident rod was used as the impact load.Meanwhile,the variations in crack speed,displacement,and dynamic stress intensity factor during crack propagation were obtained using an experimental system of digital laser dynamic caustics,and the commercial software ABAQUS was used for numerical simulations.From the experiments and numerical simulations,the crack propagation path was verified and the impact fracture behavior of a semicircular-arch roadway with different defect positions was presented.The results show that when the pre-fabricated crack is on the central axis of the sample,the crack propagation is purely mode I;when the pre-fabricated crack is 5 mm from the central axis,the crack propagation alternates between mode I and a mixture of modes I and II;when the pre-fabricated crack is at the edge of the semicircular-arch roadway,the crack propagation follows the I-II mixed mode.

关键词： Defect location Dynamic caustics Polymethyl methacrylate ABAQUS Semicircular-arch roadway

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深部致密砂岩气藏氮气钻井安全风险控制技术研究及应用

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钻采工艺 2024年第1期47卷 39-44页

作者：许期聪王春生李宬晓刘殿琛颜海中国石油川庆钻探公司钻采工程技术研究院四川省广汉市618300 中国石油塔里木油田公司

氮气钻井在深部致密砂岩气藏开发方面具有显著优势,但如何确保绝对安全是其面临的首要难题。文章首先分析了深部致密砂岩气藏氮气钻井面临的井下岩爆、井壁失稳、地层产水(产油)、井口装置失效(排砂管线失效)四个主要风险;其次开展了地... 详细信息

氮气钻井在深部致密砂岩气藏开发方面具有显著优势,但如何确保绝对安全是其面临的首要难题。文章首先分析了深部致密砂岩气藏氮气钻井面临的井下岩爆、井壁失稳、地层产水(产油)、井口装置失效(排砂管线失效)四个主要风险;其次开展了地面控制装备优化研究,为高压储层氮气钻井井口装置升级和优化配置提出了建议;然后开展了安全风险参数响应特征研究,并据此基于卷积神经网络开发了气体钻井随钻安全监测智能预警技术;最后针对井下岩爆、井壁失稳、地层出水三种主要风险提出了控制措施,可直接指导现场作业。

关键词：致密砂岩气藏氮气钻井安全风险控制技术装备优化

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甲醇喷射器腐蚀磨损性能研究

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现代车用动力 2024年第1期 46-48,55页

作者：李成校欧阳玲湘杨毅南岳电控(衡阳)工业技术股份有限公司湖南衡阳421007

相比传统的汽油及柴油,甲醇燃料腐蚀性更强。甲醇喷射器材料的耐腐蚀性决定了喷射器的工作可靠性,对甲醇喷射器结构和工作原理进行介绍,同时对甲醇喷射器关键运动副材料进行耐腐蚀性研究,最后对甲醇喷射器进行可靠性试验验证,为甲醇发... 详细信息

相比传统的汽油及柴油,甲醇燃料腐蚀性更强。甲醇喷射器材料的耐腐蚀性决定了喷射器的工作可靠性,对甲醇喷射器结构和工作原理进行介绍,同时对甲醇喷射器关键运动副材料进行耐腐蚀性研究,最后对甲醇喷射器进行可靠性试验验证,为甲醇发动机应用和推广提供一定的借鉴。

关键词：甲醇燃料甲醇喷射器耐腐蚀可靠性

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Boosting photocatalytic activity through tuning electron spin states and external magnetic fields

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Journal of Materials Science & Technology 2022年第20期115卷 208-220页

作者： chengxiao Peng Wenjuan Fan Qian li Wenna Han Xuefeng Chen Guangbiao Zhang Yuli Yan Qinfen Gu Chao Wang Huarong Zhang Peiyu Zhang Institute for Computational Materials Science School of Physics and ElectronicsHenan UniversityKaifeng 475004China International Joint Research Laboratory of New Energy Materials and Devices of Henan Province Kaifeng 475004China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China State Key Laboratory of Advanced Special Steels Shanghai Key Laboratory of Advanced FerrometallurgySchool of Materials Science and EngineeringShanghai UniversityShanghai 200444China Australian Synchrotron ANSTO800 Blackburn RdClayton3168VICAustralia

Photocatalysis is considered as one of the most promising technologies to generate renewable energy and degrade environmental pollutants.Tremendous efforts have been made to improve photocatalytic efficiency.Among these,tuning spin polarization and introducing an external magnetic field are considered two promising strategies to boost photocatalytic performance.Herein this review highlights the recent breakthroughs through manipulating spin states and applying external magnetic fields for enhancing photocatalytic reactions.The relevant characterization techniques and fundamental mechanisms are summarized.Spin polarization states of photocatalysts have received considerable attention due to their unique roles,including inhibiting the recombination of photoexcited carriers owing to spin orientation constraint,enhancing the reaction product selectivity,and reducing the reaction barriers via optimizing the absorption energy and binding strength.As for the effects of external magnetic field on photocatalytic performance,we mainly discuss the separation enhancement of photoinduced carriers under static and time-varying magnetic fields and the magneto-hydrodynamic effect of charged particles.Lastly,the negative magnetoresistance effect is discussed due to the synergistic effects of the electron spin state and an external magnetic field.These discussions in this review may provide new insights into designing new semiconductors for boosting photocatalytic performance in internal and external magnetic fields.

关键词： Spin states External magnetic field light adsorption Charges separation Reaction barrier

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小麦钼营养研究进展

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山东农业科学 2024年第6期56卷 173-180页

作者：贾琳刘春奎胡承孝李紫琳刘红恩秦世玉张博莹孙学成李科都赵祯博小麦玉米作物学国家重点实验室/河南农业大学农学院河南郑州450046 郑州轻工业大学食品与生物工程学院河南郑州450001 新型肥料湖北省工程实验室/华中农业大学微量元素研究中心湖北武汉430070 河南农业大学资源与环境学院河南郑州450046

钼是小麦生长所必需的一种微量元素,对小麦的生长发育有重要作用,影响小麦的生理代谢、产量和品质等。本文综述了目前我国土壤中钼含量及其有效性,施钼对小麦生理代谢、钼的吸收分配、吸收效率及其基因表达的影响,以及施钼对小麦生长发... 详细信息

钼是小麦生长所必需的一种微量元素,对小麦的生长发育有重要作用,影响小麦的生理代谢、产量和品质等。本文综述了目前我国土壤中钼含量及其有效性,施钼对小麦生理代谢、钼的吸收分配、吸收效率及其基因表达的影响,以及施钼对小麦生长发育、籽粒产量和品质及其抗逆性影响等的研究现状,并对今后开展小麦钼营养研究的重点方向进行了展望。

关键词：钼营养小麦生长发育生理代谢抗逆性钼转运基因

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考虑拥堵状况的城市主城区小学设施可达性研究

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山东交通科技 2024年第2期 25-28页

作者：李忠锐刘光辉范宏贤赵欢欢甘印城李骋霄山东交通学院交通与物流工程学院山东济南250357 山东公路技师学院山东济南250000 山东交通学院顿河学院山东济南250357

基于poi数据、交通态势数据采用栅格耗费距离法对小学教育设施可达性进行研究,并以济南市主城区小学教育设施为研究对象,对比分析不同出行方式下的小学教育设施的可达性。结果表明:济南市小学教育设施可达性特征是市中区北部与天桥区南... 详细信息

基于poi数据、交通态势数据采用栅格耗费距离法对小学教育设施可达性进行研究,并以济南市主城区小学教育设施为研究对象,对比分析不同出行方式下的小学教育设施的可达性。结果表明:济南市小学教育设施可达性特征是市中区北部与天桥区南部可达性较好,南部山区以及历下区南部千佛山黄金谷附近受地形因素影响可达性相对较差,黄河以北地区的可达性有待改善。机动车出行与自行车出行的可达性差异不明显,在一些偏远地区机动车的可达性优势较大,而机动车与自行车的可达性明显优于步行方式的可达性。

关键词：城市交通道路交通可达性分析栅格成本距离分析法

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Synthesis and Crystal Structure of a Novel 3D Magnesium(II) Coordination Polymer Constructed by Flexible Benzene-1,4-dioxyacetate

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Chinese Journal of Structural Chemistry 2005年第6期24卷 629-632页

作者： GAOShan HUOli-Hua chengxiao-li liUJi-Wei LabortatoryofFunctionalMaterials SchoolofChemistryandMaterialsScienceHeilongjiangUniversityHarbin150080China

A novel coordination polymer of [Mg(1,4-BDOA)(CH3OH)2]n (1,4-BDOA2– = benzene-1,4-dioxyacetate dianion) has been synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction. The crystal crystallizes in monoclinic system, space group P21/c, with a = 12.070(2), b = 7.7088(15), c = 7.3332(15) ?, β = 91.42(3)o, V = 682.1(2) ?3, Z = 2, Mr = 312.56, Dc = 1.522 g/cm3, μ = 0.168 mm–1, F(000) = 328, the final R = 0.0628 and wR = 0.1591 for 1082 observed reflections with I > 2σ(I). The Mg(II) atom and 1,4-BDOA2– ligand lie in different inversion centers. The Mg(II) atom shows an octahedral geometry defined by four carboxyl O atoms from four different 1,4-BDOA2– ligands and two hydroxyl O atoms from two methanol molecules. The Mg(II) atoms are bridged by 1,4-BDOA2– ligands, leading to a 3D infinite network structure.

关键词： magnesium(II) complex benzene-1,4-dioxyacetic acid synthesis crystal structure

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血必净注射液对LPS诱导的急性肺损伤大鼠炎症反应及细胞凋亡的影响

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湖南中医药大学学报 2024年第4期44卷 538-544页

作者：赖桂花谭金曲李萌萌付成效曾亚华王婷王娟廖念周君屈萌艰南华大学附属第一医院康复医学中心湖南衡阳421001 南华大学附属第一医院康复医学科湖南衡阳421001 南华大学附属第一医院针灸/康复医学实验室湖南衡阳421001 南华大学附属第一医院药学部湖南衡阳421001

目的观察血必净注射液对脂多糖(lipopolysaccharide,LPS)诱导的急性肺损伤大鼠炎症反应及细胞凋亡的影响。方法将30只雄性SD大鼠随机分为正常组(10只)和造模组(20只),造模组造模后(尾静脉注射LPS)随机分为模型组(10只)和血必净注射液组... 详细信息

目的观察血必净注射液对脂多糖(lipopolysaccharide,LPS)诱导的急性肺损伤大鼠炎症反应及细胞凋亡的影响。方法将30只雄性SD大鼠随机分为正常组(10只)和造模组(20只),造模组造模后(尾静脉注射LPS)随机分为模型组(10只)和血必净注射液组(10只)。采用肺组织湿重/干重评估肺组织水肿程度,EliSA检测血清炎症因子IL-6、IL-1β、IL-4和IL-18的水平,HE染色观察大鼠肺组织病理损伤情况,TUNEL染色观察肺组织细胞凋亡情况,RT-PCR和Western blot检测凋亡因子胱天蛋白酶-3(Caspase-3)和胱天蛋白酶-8(Caspase-8)的mRNA含量和蛋白水平。结果与正常组比,模型组大鼠肺组织湿重/干重升高(P<0.01),IL-6、IL-1β、IL-4和IL-18升高(P<0.001),肺组织出现损伤和炎症浸润,细胞凋亡率升高(P<0.001),Caspase-3和Caspase-8的mRNA、蛋白表达升高(P<0.01或P<0.001)。与模型组比,血必净注射液组大鼠肺组织湿重/干重下降(P<0.05),IL-6、IL-1β、IL-4和IL-18降低(P<0.05或P<0.01),肺组织损伤和炎症浸润情况明显改善,细胞凋亡率下降(P<0.001),Caspase-3和Caspase-8的mRNA和蛋白表达降低(P<0.01或P<0.001)。结论血必净注射液可改善急性肺损伤大鼠的肺组织损伤和炎症反应,其机制可能与抑制细胞凋亡有关。

关键词：急性肺损伤血必净注射液炎症反应细胞凋亡胱天蛋白酶-3 胱天蛋白酶-8

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