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Influence of depressurization rate on gas production capacity of high-rank coal in the south of Qinshui Basin, China 预览
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作者 SU Xuefeng LIU Yan +3 位作者 CUI Zhouqi ZHANG Jianguo YU Li WANG Kai 《石油勘探与开发:英文版》 2019年第3期642-650,共9页
A desorption simulation experiment with the condition of simulated strata was designed. The experiment, under different depressurizing rates and the same fluid saturation, was conducted on the sample from 3# coal of D... A desorption simulation experiment with the condition of simulated strata was designed. The experiment, under different depressurizing rates and the same fluid saturation, was conducted on the sample from 3# coal of Daning coal mine in Jincheng, Shanxi Province. The gas production rate and pressure change at both ends of the sample were studied systematically, and the mechanisms of some phenomena in the experiment were discussed. The experimental results show that, whether at fast or slow depressurizing rate, the methane adsorbed to high-rank coal can effectively desorb and the desorption efficiency can reach above 90%. There is an obvious inflection point on the gas yield curve during the desorption process and it appears after the pressure on the lump of coal reduces below the desorption pressure. The desorption of methane from high-rank coal is mainly driven by differential pressure, and high pressure difference is conducive to fast desorption. In the scenario of fast depressurization, the desorption inflection appears earlier and the gas production rate in the stage of rapid desorption is higher. It is experimentally concluded that the originally recognized strategy of long-term slow CBM production is doubtful and the economic benefit of CBM exploitation from high-rank coal can be effectively improved by rapid drainage and pressure reduction. The field experiment results in pilot blocks of Fanzhuang and Zhengzhuang show that by increasing the drainage depressurization rate, the peak production of gas well would increase greatly, the time of gas well to reach the economic production shortened, the average time for a gas well to reach expected production reduced by half, and the peak gas production is higher. 展开更多
关键词 Qinshui Basin Fanzhuang BLOCK Zhengzhuang BLOCK high-rank COAL DEPRESSURIZATION RATE gas production RATE simulation experiment gas production capacity
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THE HIGH ORDER BLOCK RIP CONDITION FOR SIGNAL RECOVERY
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作者 Yaling Li Wengu Chen 《计算数学:英文版》 SCIE CSCD 2019年第1期61-75,共15页
In this paper,we consider the recovery of block sparse signals,whose nonzero entries appear in blocks (or clusters)rather than spread arbitrarily throughout the signal,from incomplete linear measurements.A high order ... In this paper,we consider the recovery of block sparse signals,whose nonzero entries appear in blocks (or clusters)rather than spread arbitrarily throughout the signal,from incomplete linear measurements.A high order sufficient condition based on block RIP is obtained to guarantee the stable recovery of all block sparse signals in the presence of noise,and robust recovery when signals are not exactly block sparse via mixed l2/l1 minimization.Moreover,a concrete example is established to ensure the condition is sharp.The significance of the results presented in this paper lies in the fact that recovery may be possible under more general conditions by exploiting the block structure of the sparsity pattern instead of the conventional sparsity pattern. 展开更多
关键词 BLOCK SPARSITY BLOCK RESTRICTED ISOMETRY property Compressed sensing Mixed l2/l1 MINIMIZATION
Linux下Ext3文件系统结构研究 预览
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作者 苏神保 刘丹 《智能计算机与应用》 2019年第4期304-306,312共4页
在Linux操作系统中,磁盘的分区结构与Windows系统一样,都采用MBR或者GPT磁盘分区,但在文件系统的结构上却有很大的差别,Windows系统常见的文件系统有FAT32、NTFS、exFAT等,而Linux系统的则为Ext2/3/4.本文以Linux操作系统中常见文件系统... 在Linux操作系统中,磁盘的分区结构与Windows系统一样,都采用MBR或者GPT磁盘分区,但在文件系统的结构上却有很大的差别,Windows系统常见的文件系统有FAT32、NTFS、exFAT等,而Linux系统的则为Ext2/3/4.本文以Linux操作系统中常见文件系统Ext3为例,详细介绍该文件系统的结构并举例说明其手工提取文件的方法. 展开更多
关键词 WINHEX EXT3 BLOCK i-节点
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The Distribution of Surface Karst Features in the Bakony Region (Transdanubian Mountains, Hungary) 预览
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作者 Marton VERESS Szilard VETeSI-FOITH 《地质研究(英文)》 2019年第1期21-35,共15页
The surface karst of the Bakony Region is described. VES measurements were applied to study the cover and the morphology of the bedrock. A karstmorphological mapping was also performed. A relation was established betw... The surface karst of the Bakony Region is described. VES measurements were applied to study the cover and the morphology of the bedrock. A karstmorphological mapping was also performed. A relation was established between the karst types and block types in the mountains. The karstification of the mountains was affected by the block structure of the mountains, the mounds of the uneven bedrock, the presence of superficial deposits and their young denudation. As a result of the above mentioned facts, the karst of the mountains is varied. Soil-covered karst is wide spread in the mountains, but the specific features of this type (solution dolines) only occur on threshold surfaces at the margin of the mountains and on dolomite. The concealed karst was mainly formed on horsts elevated to summit position, but it can also be found on threshold surfaces and on horsts in summit position. Its features are subsidence dolines and depressions of superficial deposit. Cryptokarst and buried karst can be created by gravelly cover or basalt. Where the cover is gravel, epigenetic valleys develop with opened-up phreatic cavities. Where the cover is basalt, ponors develop at its margin, while inside, where the basalt thins out, caprock dolines are formed. 展开更多
关键词 Block TYPE KARST TYPE SUBSIDENCE doline CAPROCK doline Ponor GORGE
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关于Jordan标准形的教学探讨 预览
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作者 谢凤艳 《大学教育》 2019年第8期108-110,共3页
Jordan标准形反映了矩阵的本质性质并且是形式最为简单的方阵.结合教学实践,从教学过程中强化Jordan标准形矩阵是对角矩阵的推广和延伸,通过典型例题讲解,融入Matlab软件,强调应用四个方面对Jordan标准形的教学进行探讨,旨在加深学生对J... Jordan标准形反映了矩阵的本质性质并且是形式最为简单的方阵.结合教学实践,从教学过程中强化Jordan标准形矩阵是对角矩阵的推广和延伸,通过典型例题讲解,融入Matlab软件,强调应用四个方面对Jordan标准形的教学进行探讨,旨在加深学生对Jordan标准形的认识. 展开更多
关键词 方阵 Jordan块 JORDAN标准形 Matlab SQUARE MATRIX JORDAN BLOCK
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Open tubular capillary electrochromatography with block co-polymer coating for separation of β-lactam antibiotics
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作者 Liping Zhao Juan Qiao +2 位作者 Hongyi Zhang Fangnan Xie Li Qi 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第2期349-352,共4页
A new open-tubular capillary electrochromatography (OT-CEC) method for analysis of β-lactam antibiotics has been developed with unique block co-polymer coating. To obtain the highly ordered block polymer chains, reve... A new open-tubular capillary electrochromatography (OT-CEC) method for analysis of β-lactam antibiotics has been developed with unique block co-polymer coating. To obtain the highly ordered block polymer chains, reversible addition fragmentation chain transfer radical polymerization method was used to synthesize poly (maleic anhydride-styrene-N-isopropylacrylamide). The prepared block copolymer coating was characterized with NMR, fourier transform infrared spectroscopy and scanning electron microscope. Several key separation factors of OT-CEC, which including polymer amount,stability of the coating, temperature, species of organic additives, buffer pH and concentration, were investigated in detail. Our results indicated that the separation efficiency was improved greatly with the coating capillary and the three test analytes could be baseline separated. Then, the separation mechanism was briefly explored. Moreover, the proposed OT-CEC method displayed promising quantitative analysis property of the three test analytes with good linearity (R2>0.99), repeatability (relative standard deviations <0.9%) and high recovery (95.4%-106.2%). Further, the assay was applied in monitoring the three test β-lactam antibiotics (cephradine, cephalexin and amoxicillin) in serum samples, providing a useful platform for construction of novel polymer coatings in OT-CEC system and for analysis of drugs in real bio-samples. 展开更多
关键词 OPEN-TUBULAR capillary ELECTROCHROMATOGRAPHY β-Lactam antibiotics BLOCK CO-POLYMER COATING Serum drugs SEPARATION
澳门当代住区中的骑楼——以黑沙环填海区为例
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作者 张贝贝 薛佳薇 《中外建筑》 2019年第8期99-102,共4页
骑楼,早期原型为殖民地券廊式建筑,近代发展起来的一种特殊建筑形式,是气候与地方经济文化结合的产物。漫步于澳门旧城区,骑楼建筑随处可见,骑楼在近代有较为广泛的传播和应用,同时,在澳门城市发展的快速期,骑楼作为一种文化载体、集体... 骑楼,早期原型为殖民地券廊式建筑,近代发展起来的一种特殊建筑形式,是气候与地方经济文化结合的产物。漫步于澳门旧城区,骑楼建筑随处可见,骑楼在近代有较为广泛的传播和应用,同时,在澳门城市发展的快速期,骑楼作为一种文化载体、集体记忆,与澳门现代建筑相结合,以崭新的形式出现在现代化建设当中。功能方面,骑楼不再局限于商业建筑,与当代住区也有紧密的结合;形式方面,骑楼不再局限于上宅下商或后宅前商的建筑形式,形式更加多样化。由此可见,骑楼不仅仅局限于旧城建设中,在当代住区建设中亦可有实践应用。本文通过实地调研,通过研究分析黑沙环填海区的建设案例,总结澳门当代骑楼住区的布局方式,骑楼街道空间尺度和骑楼空间构成,并对骑楼在当代住区建设中的应用和发展提出建议。 展开更多
关键词 澳门 骑楼 街区 空间尺度
On the Distance Spectra of Several Double Neighbourhood Corona Graphs
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作者 Xiaojing XU Zhiping WANG Jiaxue XU 《数学研究及应用:英文版》 CSCD 2019年第3期233-248,共16页
Let G be a connected graph of order n and D(G) be its distance matrix. The distance eigenvalues of G are the eigenvalues of its distance matrix. Its distance eigenvalues and their multiplicities constitute the distanc... Let G be a connected graph of order n and D(G) be its distance matrix. The distance eigenvalues of G are the eigenvalues of its distance matrix. Its distance eigenvalues and their multiplicities constitute the distance spectrum of G. In this article, we give a complete description of the eigenvalues and the corresponding eigenvectors of a block matrix DNC. Further, we give a complete description of the eigenvalues and the corresponding eigenvectors of distance matrix of double neighbourhood corona graphs G(S)· {G1, G2}, G(Q)· {G1, G2}, G(R)· {G1, G2},G(T)· {G1, G2}, where G is a complete graph and G1, G2 are regular graphs. 展开更多
关键词 CORONA DISTANCE spectrum DOUBLE neighbourhood CORONA GRAPH block matrix
右美托咪定联合罗哌卡因肋间神经阻滞在婴儿胸腔镜手术术后镇痛效果的观察 预览
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作者 陈祥楠 杨世辉 +5 位作者 刘晶 黄微 罗超荣 李敏 何健珊 胡祖荣 《中国医药科学》 2019年第14期91-93,共3页
目的探讨右美托咪定联合罗哌卡因肋间神经阻滞在婴儿胸腔镜手术术后镇痛的功效。方法拟择期行胸腔镜下隔离肺切除术的90例婴儿,随机分为三组:右美托咪定联合罗哌卡因肋间神经阻滞组(D组),单独罗哌卡因肋间神经阻滞组(R组),对照组(C组)... 目的探讨右美托咪定联合罗哌卡因肋间神经阻滞在婴儿胸腔镜手术术后镇痛的功效。方法拟择期行胸腔镜下隔离肺切除术的90例婴儿,随机分为三组:右美托咪定联合罗哌卡因肋间神经阻滞组(D组),单独罗哌卡因肋间神经阻滞组(R组),对照组(C组)。关胸前15min在胸腔镜直视协助下进行肋间神经阻滞,D组患儿各注入0.25μg/kg的右美托咪定+1mg/mL罗哌卡因的混合注射液(0.1mL/kg),R组患儿各注入1mg/mL罗哌卡因注射液(0.1mL/kg)。记录患儿拔出气管导管时(T0)、拔出气管导管后6h(T1)、12h(T2)、24h(T3)的CRIES疼痛评分。同时记录不良反应,如呼吸抑制、心率减慢等。结果在T0、T1时,患儿的CRIES评分比较:D组较R组低(P<0.05),D组与R组均较C组低(P<0.05);其余时间段,三组患儿的CRIES评分比较差异无统计学意义(P>0.05)。三组患儿均未出现抑制呼吸、心率减慢等不良反应。结论婴儿胸腔镜手术应用右美托咪定联合罗哌卡因肋间神经阻滞,具有较好的镇痛功效。 展开更多
关键词 肋间神经 阻滞 胸腔镜 婴儿 镇痛 右美托咪定 罗哌卡因
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Precambrian Captured Zircon Ages in the Daheigou Formation, Xing'an Block 预览
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作者 SONG Wanbing CUI Fanghua +4 位作者 YANG Hongzhi ZHANG Li WU Xinwei SHI Jianmin ZHANG Chao 《地质学报:英文版》 SCIE CAS CSCD 2019年第3期758-759,共2页
The Xing'an Block (XB) is located between the Erguna Block (EB) and the Songnen Block (SB), which topographically occupies the northeastern half of the Great Xing'an Range (Liu et al., 2017). The XB was tr... The Xing'an Block (XB) is located between the Erguna Block (EB) and the Songnen Block (SB), which topographically occupies the northeastern half of the Great Xing'an Range (Liu et al., 2017). The XB was traditionally considered to be composed of a Precambrian metamorphic basement and post-Cambrian cover. However, the recent geochronological studies show that the so-called "Precambrian metamorphic rocks^^ are much younger in age and considered to be formed in the Early Paleozoic, indicating no existence of the Precambrian metamorphic basement. 展开更多
关键词 Xing'an BLOCK PRECAMBRIAN CAPTURED ZIRCON AGES
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块体稳定性影响因素的敏感性分析 预览
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作者 张争 刘永智 石广斌 《西北水电》 2019年第3期16-19,共4页
通过正交数值试验方法研究了黏聚力、内摩擦角和爆破振动3个因素对块体稳定性影响的敏感性,试验结果表明:3个因素对块体的稳定性均有影响,存在主次顺序,其中爆破振动对块体的稳定性影响是最敏感的,随着爆破振动的增加,安全系数明显降低... 通过正交数值试验方法研究了黏聚力、内摩擦角和爆破振动3个因素对块体稳定性影响的敏感性,试验结果表明:3个因素对块体的稳定性均有影响,存在主次顺序,其中爆破振动对块体的稳定性影响是最敏感的,随着爆破振动的增加,安全系数明显降低,成负相关趋势,黏聚力次之,最后是内摩擦角,后两者随着数值增大,安全系数增加,成正相关趋势。由此建议工程开挖中,遇到构造断裂发育的地段,一方面要做好控制爆破,对于隧洞掘进方面,宜用机械方式开挖,减少对围岩的扰动及损伤;另一方面及时支护,降低结构面间的黏聚力损失,提高工程作业安全性和作业效率。 展开更多
关键词 块体 正交试验 敏感性 结构面
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改进K均值聚类的海洋数据异常检测算法研究 预览
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作者 蒋华 武尧 +1 位作者 王鑫 王慧娇 《计算机科学》 CSCD 北大核心 2019年第7期211-216,共6页
针对海洋Argo浮标监测数据中的异常数据挖掘问题,在改进K均值算法的基础上,提出基于距离为准则进行海洋异常数据判定的异常检测算法。该算法重新定义海洋数据邻近度,并根据数据的规模以及分布情况,区块化、自适应地筛选备选初始聚类中心... 针对海洋Argo浮标监测数据中的异常数据挖掘问题,在改进K均值算法的基础上,提出基于距离为准则进行海洋异常数据判定的异常检测算法。该算法重新定义海洋数据邻近度,并根据数据的规模以及分布情况,区块化、自适应地筛选备选初始聚类中心;在算法迭代过程中,运用簇内,数据对象相对于聚类中心的距离均值,全局考量类簇内,符合异常特征的数据对象进行异常检测。通过仿真数据集和真实数据集分别进行实验验证,对比结果表明:该算法在聚类性能以及异常检测方面都优于对比算法。 展开更多
关键词 K-MEANS算法 Argo浮标数据 邻近度 区块化 异常检测
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碱激发矿渣陶粒混凝土砌块高温后力学性能 预览
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作者 李东辉 王英 郑文忠 《哈尔滨工业大学学报》 EI CAS CSCD 北大核心 2019年第6期46-50,共5页
为研究碱激发矿渣陶粒混凝土砌块高温后力学性能,完成了MU10和MU20两个强度等级常温下及历经400、600、700、800、900、1 000、1 100℃高温后各24个碱激发矿渣陶粒混凝土砌块抗压试验.发现MU10和MU20砌块高温后抗压强度在20~1 100℃间... 为研究碱激发矿渣陶粒混凝土砌块高温后力学性能,完成了MU10和MU20两个强度等级常温下及历经400、600、700、800、900、1 000、1 100℃高温后各24个碱激发矿渣陶粒混凝土砌块抗压试验.发现MU10和MU20砌块高温后抗压强度在20~1 100℃间随历经温度的升高而线性降低.基于试验结果,建立了高温后碱激发矿渣陶粒混凝土砌块抗压强度随历经温度而变化的计算公式. 展开更多
关键词 碱激发矿渣陶粒混凝土 砌块 历经温度 高温后 抗压强度
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Microbial Geochemical Characteristics of the Coalbed Methane in the Shizhuangnan Block of Qinshui Basin,North China and their Geological Implications 预览
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作者 LI Yang SHI Wei TANG Shuheng 《地质学报:英文版》 SCIE CAS CSCD 2019年第3期660-674,共15页
Methanogens and sulfate reducing bacteria were detected by the 16SrRNA sequencing of coalbed methane(CBM)co-produced water in the south of the Qinshui Basin,which is indicative of the presence of secondary biological ... Methanogens and sulfate reducing bacteria were detected by the 16SrRNA sequencing of coalbed methane(CBM)co-produced water in the south of the Qinshui Basin,which is indicative of the presence of secondary biological gas in the south of this basin,in contradiction to the previous understanding of thermogenic gas.This work systematically collected water samples from the CBM wells in the Shizhuangnan Block and analyzed the microbial geochemical characteristics from the aspects of water ions,hydrogen and oxygen isotopes,dissolved inorganic carbon and microbial diversity.It is shown that the Shizhuangnan Block has a nearly SN-trending monoclinic structure,and the elevation of coal seam decreases gradually from the east to west.Because of the water blocking effect of Sitou fault in the west,the precipitation flowed from the east to west,and gradually transited to stagnant flow area.The concentration variation of some ions such as Na^+,K^+,Ca2^+,Mg2^+,Cl^-,HCO3^-and total dissolved solids(TDS)suggest the variation of redox condition in the coal reservoir water.The 16SrDNA sequencing analysis of the collected water samples detected the presence of methanogens and sulfate reduction bacteria.The presence of methane production zone and sulfate methane transition zone(SMTZ)was identified.The effect of methanogens in the methane production zone leads to an increase in the methane concentration,resulting in a high gas content in the study area.In the SMTZ,most methane is consumed by anaerobic oxidation due to high sulfate concentrations. 展开更多
关键词 CBM co-produced water MICROBIAL geochemistry sulfate methane transition zone Shizhuangnan BLOCK
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One-step preparation of polyimide-inlaid amine-rich porous organic block copolymer for efficient removal of chlorophenols from aqueous solution
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作者 Yanyang Liu Haijian Ou +4 位作者 Shangqing Li Qingliang You Huixian Liu Guiying Liao Dongsheng Wang 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第4期215-229,共15页
A novel polyimide-inlaid amine-rich porous organic block copolymer(PI-b-ARPOP) was prepared via one-step polymerization by using different molar ratios of melamine(MA)/terephthalaldehyde(TA)/pyromellitic dianhydride(P... A novel polyimide-inlaid amine-rich porous organic block copolymer(PI-b-ARPOP) was prepared via one-step polymerization by using different molar ratios of melamine(MA)/terephthalaldehyde(TA)/pyromellitic dianhydride(PMDA), at molar ratios of 4/3/1, 4/2/2 and 4/1/3. The copolymer contained both aminal groups belonging to ARPOP and imide groups belonging to PI, and the bonding styles of the monomers and growth orientations of the polymeric chains were diversiform, forming an excellent porous structure. Notably, MA/TA/PMDA(4/2/2) had a surface area and pore volume of 487.27 m~2/g and 1.169 cm~3/g,respectively. The adsorption performance of the materials towards 2,4-dichlorophenol(2,4-DCP) in ultra-pure water was systematically studied. The pH value of 7 was optimal in aqueous solution. Na~+ and Cl~-ions did not negatively affect the adsorption process, while humic acid(HA) slightly decreased the capacity. The equilibrium time was 40 sec, and the maximum adsorption capacity reached 282.49 mg/g at 298 K. The removal process was endothermic and spontaneous, and the copolymer could maintain its porous structure and consistent performance after regeneration by treatment with alkali. Moreover, to further assess the practical applicability of the material, the adsorption performance towards 2,4-DCP in river water was also investigated. This paper demonstrated that the PI-b-ARPOP can be an efficient and practical adsorbent to remove chlorophenols from aqueous solution. 展开更多
关键词 POROUS block copolymer SCHIFF base POLYIMIDE Adsorption 2 4-DICHLOROPHENOL
论析再生纤维造纸中毛毯洗涤的核心方案 预览
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作者 陈传勇 吴飞燕 童含信 《造纸化学品》 CAS 2019年第4期15-18,共4页
现代造纸过程中大量使用再生纤维,添加多种淀粉及其他造纸化学品,以及白水封闭循环程度的提高,使得毛毯表面和内部黏附了种类繁多的污垢物,影响了毛毯的透气度和弹性。该文分析了毛毯变脏的原因、堵塞物组成成分,针对性地采取有效的在... 现代造纸过程中大量使用再生纤维,添加多种淀粉及其他造纸化学品,以及白水封闭循环程度的提高,使得毛毯表面和内部黏附了种类繁多的污垢物,影响了毛毯的透气度和弹性。该文分析了毛毯变脏的原因、堵塞物组成成分,针对性地采取有效的在线洗涤手段,清除了毛毯表面及内部的有机和无机污垢物。 展开更多
关键词 再生纤维造纸 毛毯 堵塞物 机械洗涤 化学洗涤
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激光引燃自蔓延烧结AlCrFeNiSix多孔高熵合金组织及性能 预览
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作者 李刚 邱信伟 +3 位作者 宋艳东 郭玉洁 付晓帆 刘志刚 《有色金属工程》 CAS 北大核心 2019年第4期28-33,共6页
为探究Si含量的变化对AlCrFeNiSi系高熵合金组织及性能的影响规律,采用激光诱导自蔓延烧结制备AlCrFeNiSix(x=0.2,0.4,0.6,0.8,1.0)多孔高熵合金。利用金相光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)、硬度... 为探究Si含量的变化对AlCrFeNiSi系高熵合金组织及性能的影响规律,采用激光诱导自蔓延烧结制备AlCrFeNiSix(x=0.2,0.4,0.6,0.8,1.0)多孔高熵合金。利用金相光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、X射线衍射(XRD)、硬度测试等表征分析了不同Si含量的AlCrFeNiSix多孔高熵合金材料显微组织、物相结构、合金密度和孔隙率、维氏硬度及耐磨性能。结果表明,合金组织内部均匀分布微观孔隙,x=0.4时,合金孔隙分布最为均匀。x≤0.4时,合金由BCC相构成,x超过0.6时,合金在BCC相结构的基础上出现FCC相。AlCrFeNiSi0.6高熵合金硬度最大,为522.3HV0.5;磨损率最小,为73.41mg/cm^2;密度最大,为4.354g/cm^3;孔隙率最低,为17.1%。x=0.2时,合金孔隙率最大,为39.92%。 展开更多
关键词 高熵合金 激光烧结 多孔材料 块体 孔隙率
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光岳楼木结构自振频率计算方法 预览
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作者 廖茹梦 孟昭博 +1 位作者 王贺 耿园园 《建材与装饰》 2019年第14期73-75,共3页
采用ITD(Ibrahim Time Domain)方法对聊城光岳楼进行模态分析,得到前6阶自振频率;利用ANSYS有限元分析软件建立光岳楼木结构有限元模型,并采用Block Lanczos方法计算光岳楼木结构前6阶自振频率;对比ITD法与有限元分析法分别计算得到的... 采用ITD(Ibrahim Time Domain)方法对聊城光岳楼进行模态分析,得到前6阶自振频率;利用ANSYS有限元分析软件建立光岳楼木结构有限元模型,并采用Block Lanczos方法计算光岳楼木结构前6阶自振频率;对比ITD法与有限元分析法分别计算得到的自振频率。结果表明院采用ITD法拟合的光岳楼振动响应曲线的发展趋势与实测值曲线基本吻合;采用Block Lanczos方法计算得到的前3阶自振频率与ITD法计算结果相差甚小,但后3阶自振频率均小于ITD法计算结果,因此采用ANSYS有限元分析软件Block Lanczos模态计算方法计算的自振频率更能反映光岳楼的实际自振频率。 展开更多
关键词 ITD方法 BLOCK LANCZOS方法 自振频率
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引黄滴灌滴灌器堵塞室内模拟试验研究 预览
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作者 杜慧慧 马太玲 +3 位作者 于健 王利明 卢俊平 赵琳琳 《人民黄河》 CAS 北大核心 2019年第1期149-151,156共4页
针对内蒙古乌海市农林灌溉工程中滴灌带堵塞的问题,取用该地区引黄滴灌原水进行室内模拟试验,在不同水质及环境状况下研究滴灌器堵塞情况,分析滴灌器堵塞的主要影响因素。经6组对比试验研究确定,影响滴灌器堵塞的主要水质指标是浊度和... 针对内蒙古乌海市农林灌溉工程中滴灌带堵塞的问题,取用该地区引黄滴灌原水进行室内模拟试验,在不同水质及环境状况下研究滴灌器堵塞情况,分析滴灌器堵塞的主要影响因素。经6组对比试验研究确定,影响滴灌器堵塞的主要水质指标是浊度和微生物总数,且二者有很高的相关性;主要环境因子是水温。含沙量越大,灌水均匀度越小,滴灌器堵塞速度越快。温度越高,灌水均匀度变化幅度越大,进而对滴灌器流量的影响越明显。微生物(主要测定细菌总数)附着在泥沙颗粒上,与泥沙协同作用造成对滴灌器的堵塞;而浊度的增大和水温的升高促使微生物的数量增加。 展开更多
关键词 滴灌器 堵塞 室内试验 浊度 细菌总数 水温
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Forecasting vulnerability of deep extraction level excavations to drawinduced cave loads 预览
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作者 Matthew E.Pierce 《岩石力学与岩土工程学报:英文版》 CSCD 2019年第3期527-534,共8页
Block and panel caving methods are increasingly used for mining of large and strong orebodies at large depths below the ground surface (>1 km). This paper focuses on the production phase of caving when the extracti... Block and panel caving methods are increasingly used for mining of large and strong orebodies at large depths below the ground surface (>1 km). This paper focuses on the production phase of caving when the extraction level is fully developed and subjected to the weight of overlying caved material. A limit equilibrium solution for estimation of cave loads is critically reviewed and combined with existing empirical tools in order to forecast extraction level performance under cave loading. The analysis results, presented in nomogram form, suggest that the risk of severe squeezing of extraction level tunnels does not increase with cave depths below 500-1000 m due to the beneficial effects of arching. Under normal extraction ratios (ER = ~50%), severe squeezing experienced from cave loads in deep mines appears to be unlikely in all but the weakest rock masses (σcm < 5 MPa, where σcm is the rock mass global strength), even with poor draw control or low drawpoint availability. The likelihood of severe squeezing is greater when large draw areas (HR = 50-75 m, where HR is the hydraulic radius) are combined with low drawpoint availability or poor draw control and locally higher extraction ratios (ER = ~75%), even in better quality rock (σcm = 5-10 MPa). The analysis results are back-analyzed with the extraction level performance before and after a doubling production of rate and draw area at the deep ore zone (DOZ) mine in Indonesia. The extraction level conditions predicted by the nomograms correlate well with the experience at the DOZ, in which extraction level damage increases significantly over the production rampup, accompanied by a significant drop in drawpoint availability. 展开更多
关键词 Block CAVING Panel CAVING Extraction level DRAW control SQUEEZING
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