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Effect of Silica Fume on Mechanical Properties of Concrete Incorporating Steel Slag Powder

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Wuhan University Journal of Natural Sciences 2019年第1期24卷 86-92页

作者： LUO xiaobao SI Yayu GU Wanqing School of Civil Engineering and Architecture Anhui University of Science and Technology

This study investigated the effect of silica fume(SF) on mechanical properties of concrete incorporating steel slag powder(SSP). The compressive strength and splitting strength tests of concrete with different content of SF(0%, 4%, 8% and 12.) and of SSP(0%, 10%, 2.%, 30% and 40%) were carried out, and the test results were analyzed and fitted. Obtained results showed that the brittleness, compressive strength and compressive strength discreteness of concrete increased due to the incorporation of SF. SSP weakened the compressive strength of concrete, which reduced within 10% when the content of SSP was less than 2.%. SF and SSP showed synergistic hydration effect when they were mixed, and the optimal group was SF8 SSP30, whose compressive strength was close to that of plain concrete, and whose brittleness as well as discreteness of compressive strength were lower relatively. With the content of SSF and of SSP as variables, the tension-compression ratio and compressive strength of concrete can be well estimated by surface fitting.

关键词： silica fume steel slag powder concrete compressive strength brittleness discreteness surface fitting

三相LCL-LC型仅网侧反馈的改进时滞抑制

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现代电子技术 2024年第15期47卷 139-145页

作者：李小宝梁登辉周维龙周红龙欢柳骏涛湖南工业大学电气与信息工程学院湖南株洲412000

LCL-LC电压源型逆变器仅网侧电流反馈的有源阻尼相比于电容电流反馈下的有源阻尼减少了检测元件的使用,能有效抑制LCL-LC逆变器产生的谐振峰。但由于数字电路里存在控制延时影响,因此电网阻抗的变化会引起谐振频率fr偏移,当fr处于采样频... 详细信息

LCL-LC电压源型逆变器仅网侧电流反馈的有源阻尼相比于电容电流反馈下的有源阻尼减少了检测元件的使用,能有效抑制LCL-LC逆变器产生的谐振峰。但由于数字电路里存在控制延时影响,因此电网阻抗的变化会引起谐振频率fr偏移,当fr处于采样频率fs的16附近时系统将会失稳。为了解决LCL-LC有源阻尼逆变器仅网侧反馈时控制延时对逆变器的影响,研究了在数字域下电网阻抗的变化对系统稳定性的影响,并提出了一种新的延时补偿方法,即在控制回路的前向通路中加入改进型延时补偿,将有源阻尼的等效正电阻从原有的fs 6扩展到0.4965fs,补偿后的有缘阻尼在fr发生偏移时由于等效正电阻的扩宽使得系统在fs 6附近不会失稳,从而极大地提升了系统的稳定性。仿真和实验验证了理论的正确性。

关键词： LCL-LC 有源阻尼逆变器时滞抑制谐振偏移延时补偿

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Helium and argon isotope geochemistry of natural gases in China's petroliferous basins

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Chinese Journal Of Geochemistry 2011年第1期30卷 19-32页

作者： LIU Wenhui XU Yongchang TAO Mingxin ZHANG xiaobao Key Laboratory of Petroleum Resources Research Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou730000 China Research Institute of Petroleum Exploration and Production SINOPEC Beijing 100083 China Key Laboratory of Environmental Change and Natural Disaster of Ministry of Education College of Resource Science andTechnology Beijing Norma University Beijing 100875 China

The age-accumulation effect of 40Ar in hydrocarbon source rocks was discussed in accordance with the decay law of radioactive elements. In terms of the mean values of 40Ar/36Ar, the old Sinian gas reservoirs (mean values of 40Ar/36Ar: 7009) were definitely distinguished from the Permian gas reservoirs (mean values of 40Ar/36Ar: 1017) in Weiyuan, Sichuan Province, and the gas source of the Permian gas reservoir (mean values of 40Ar/36Ar: 52.2. in well Wei-7 with the Weiyuan structure is defined as the Sinian system. Based on the values of 40Ar/36Ar, the coal-type gases (The source rocks are of the C-P system; mean values of 40Ar/36Ar: 112.) are definitely distinguished from the oil-type gases (The source rocks are of the Tertiary system; mean values of 40Ar/36Ar: 590) in the Tertiary reservoirs of the Zhongyuan Oilfield. Besides, 40Ar/36Ar values also have a positive effect on the oil-source correlation of oil reservoirs in ancient hidden mountains. According to the crust-mantle interchange information reflected by 3He/4He values, petroliferous provinces in China can be divided into three major tectonic regions. (1) The eastern active region: The crust-mantle volatile matter exchanges actively, and the 3He/4He values are mainly around 10-6, partly around 10-7. (2. The central stable region: The 3He/4He values are all around 10-8. (3) The western sub-stable region: The 3He/4He values are mainly around 10-8, and around 10-7 on the edges of the basins. Helium contents of some gas wells in China’s eastern petroliferous region reach the industrial abundance (He≈0.05%–0.1%), the 3He/4He values reach 10-6, and the equivalent values for the mantle-source components in helium gas can reach 30%–50%. As viewed from this, a new type of crust-mantle composite helium resources has been proposed. Geneses of some CO2.gas reservoirs in the east of China and some issues concerning mantle-source methane were discussed in the light of the helium and carbon isotopes of CO2.and CH4 in nat

关键词：中国东部地区含油气盆地天然气井同位素地球化学氦气气藏成因甲烷碳同位素区域构造运动

Hardening effects of sheared precipitates on {1121} twinning in magnesium alloys

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Journal of Magnesium and Alloys 2023年第2期11卷 580-591页

作者： Jing Tang Wentao Jiang Qingyuan Wang xiaobao Tian Dean Wei Haidong Fan Department of Mechanics Sichuan UniversityChengdu 610065China School of Mechanics and Engineering Southwest Jiaotong UniversityChengdu 610031China

The interactions between a plate-like precipitate and two twin boundaries(TBs)({1012},{1121}) in magnesium alloys are studied using molecular dynamics(MD) simulations. The precipitate is not sheared by {1012} TB, but sheared by {1121} TB. Shearing on the(110) plane is the predominant deformation mode in the sheared precipitate. Then, the blocking effects of precipitates with different sizes are studied for {1121} twinning. All the precipitates show a blocking effect on {1121} twinning although they are sheared, while the blocking effects of precipitates with different sizes are different. The blocking effect increases significantly with the increasing precipitate length(in-plane size along TB) and thickness, whereas changes weakly as the precipitate width changes. Based on the revealed interaction mechanisms, a critical twin shear is calculated theoretically by the Eshelby solutions to determine which TB is able to shear the precipitate. In addition, an analytical hardening model of sheared precipitates is proposed by analyzing the force equilibrium during TB-precipitate interactions. This model indicates that the blocking effect depends solely on the area fraction of the precipitate cross-section, and shows good agreement with the current MD simulations. Finally, the blocking effects of plate-like precipitates on the {1012} twinning(non-sheared precipitate), {1121} twinning(sheared precipitate) and basal dislocations(non-sheared precipitate) are compared together. Results show that the blocking effect on {1121} twinning is stronger than that on {1012} twinning, while the effect on basal dislocations is weakest. The precipitate-TB interaction mechanisms and precipitation hardening models revealed in this work are of great significance for improving the mechanical property of magnesium alloys by designing microstructure.

关键词： Magnesium alloys Precipitate-twin boundary interactions Sheared precipitate Precipitation hardening model Molecular dynamics simulations

Summertime Subtropical Countercurrent on isopycnals in the western North Pacific

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Chinese Science Bulletin 2002年第9期47卷 786-789页

作者： LI Rongfeng YOU xiaobao P.Chu LASG Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Department of Oceanography Naval Postgraduate SchoolMontereyCA93943USA

Circulations on isopycnals (σθ) in the western North Pacific were investigated by using P-vector method; the data were taken from the U.S. Navy’s climatological temperature and salinity dataset (public domain) with 1/2.×1/2. resolution. Results not only show the main circulation systems on isopycnals in the western North Pacific such as the North Equatorial Current (NEC), Kuroshio and Ku-roshio Countercurrent, but also reveal the Subtropical Countercurrent (STCC) clearly. In this note we pay attention to discussing the distribution of STCC in summer (in June). The STCC flows eastward along a winding road; on shallow isopycnals, the STCC originates from the area east of Bashi Strait at about 12..5°E; with the isopycnals increasing, the origin and flow core of STCC move to north and east, but the main part of STCC is still between 18?and 2..5°N, i.e. near the Tropic of Cancer. There exists STCC on all isopycnals between the sea surface and 2..8σθ.The current vectors of STCC on isopycnals are

关键词： P-vector method isopycnals Subtropical Countercur-rent.

Collective properties of neon isotopes investigated by projected shell model

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Chinese Science Bulletin 2014年第29期59卷 3847-3852页

作者： Guoxiang Dong xiaobao Wang Furong Xu Shaoying Yu State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking University Department of Physics University of Jyvskyl40014 JyvskylFinland School of Science Huzhou Teachers College

Collective phenomenon in neon isotopes is an interesting ***,even the ground-state deformations cannot be well described by ***,QJ Zhi and ZZ Ren[Phys Lett B 638:166(2.06)]have suggested an improved Nilsson potential,which can give a suitable description of ground-state properties in magnesium *** order to test the description of neon isotopes located around the‘‘island of inversion’’,we have used this potential to provide the deformed basis for the projectedshell-model *** low-lying spectra and transition properties of neon isotopes can be reproduced *** gyromagnetic factors of neon isotopes have also been *** structures of excited states along the yrast line are studied in the language of band diagrams.

关键词：氖同位素投影壳模型基态性质集体霓虹灯物理学尼尔森激发态

美洲大蠊肠道菌株WA5-1-7的初步鉴定及其抗菌活性成分的研究

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中国抗生素杂志 2024年第6期49卷 641-649页

作者：汪洁余田甜陈雪琴赵嘉怡刘文彬马艳金小宝广东药科大学基础医学院广东省生物活性药物研究重点实验室广州510006

目的对具有抗白念珠菌活性的美洲大蠊肠道来源菌株WA5-1-7进行形态学和分子生物学鉴定,并对其次级代谢物进行分离纯化,从中筛选具有抗菌活性的单体化合物。方法采用染色法和扫描电子显微镜观察菌株形态;利用PCR技术扩增菌株16S rRNA,通... 详细信息

目的对具有抗白念珠菌活性的美洲大蠊肠道来源菌株WA5-1-7进行形态学和分子生物学鉴定,并对其次级代谢物进行分离纯化,从中筛选具有抗菌活性的单体化合物。方法采用染色法和扫描电子显微镜观察菌株形态;利用PCR技术扩增菌株16S rRNA,通过其基因序列与NCBI数据库进行BLAST比对并采用N-J法构建系统发育树。菌株发酵后经乙酸乙酯溶剂萃取获得粗提物,粗提物经硅胶柱层析、葡聚糖凝胶柱层析、HPLC分离纯化,获得单体化合物,经核磁共振、质谱数据与文献比对鉴定化合物结构,并检测化合物的抗菌活性。结果菌株WA5-1-7初步鉴定为环圈链霉菌(Streptomyces anulatus),从粗提物中分离出10个化合物,分别为SF2.38F(1)、SF2.38D(2.、环(脯氨酸-亮氨酸)二肽(3)、SF2.38A(collismycin A,4)、环(苯丙氨酸-脯氨酸)二肽(5)、SF2.38C(6)、1H-吲哚甲醛(7)、大豆黄酮(8)、放线菌素X2.9)、放线菌素D(10),其中化合物4、9和10有较强抗菌活性。结论本研究从美洲大蠊肠道来源链霉菌次级代谢产物中分离出具有抗菌活性的单体化合物,为深入探索美洲大蠊肠道菌奠定了基础。

关键词：美洲大蠊链霉菌次级代谢产物抗菌活性

Padé approximations of quantized-vortex solutions of the Gross–Pitaevskii equation

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Communications in Theoretical Physics 2021年第8期73卷 171-181页

作者： Weiru Chen Shanquan Lan Xiyi Liu Jiexiong Mo xiaobao Xu Guqiang Li Institute of Theoretical Physics Lingnan Normal UniversityZhanjiang524048GuangdongChina

Quantized vortices are important topological excitations in Bose–Einstein condensates. The Gross–Pitaevskii equation is a widely accepted theoretical tool. High accuracy quantized-vortex solutions are desirable in many numerical and analytical studies. We successfully derive the Padéapproximate solutions for quantized vortices with winding numbers ω = 1, 2. 3, 4, 5, 6 in the context of the Gross–Pitaevskii equation for a uniform condensate. Compared with the numerical solutions, we find that(1) they approximate the entire solutions quite well from the core to infinity;(2. higher-order Padé approximate solutions have higher accuracy;(3) Padé approximate solutions for larger winding numbers have lower accuracy. The healing lengths of the quantized vortices are calculated and found to increase almost linearly with the winding number. Based on experiments performed with 87Rb cold atoms, the healing lengths of quantized vortices and the number of particles within the healing lengths are calculated, and they may be checked by experiment. Our results show that the Gross–Pitaevskii equation is capable of describing the structure of quantized vortices and physics at length scales smaller than the healing length.

关键词： Gross-Pitaevskii equation Padéapproximation quantized-vortex solution

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温度波动对冻藏南美白对虾品质的影响

食品与发酵工业 2024年第4期50卷 246-252页

作者：孙志利张洁玲陈小宝陈兰候思聪任彤焦峰梁迪李金涛天津商业大学机械工程学院天津300400

为研究不同温度波动对冻藏南美白对虾品质影响规律,对-18℃冷柜设定不同的温度波动(±0.5、±2.±4、±6、±8℃)来冻藏南美白对虾,测量其挥发性盐基氮(total volatile basic nitrogen,TVB-N)、硫代巴比妥酸反应物(thiobarbituric acid... 详细信息

为研究不同温度波动对冻藏南美白对虾品质影响规律,对-18℃冷柜设定不同的温度波动(±0.5、±2.±4、±6、±8℃)来冻藏南美白对虾,测量其挥发性盐基氮(total volatile basic nitrogen,TVB-N)、硫代巴比妥酸反应物(thiobarbituric acid reactive substance,TBARS)、L^(*)值、硬度、弹性、咀嚼性等指标在12. d内的变化,并与-40℃冻藏的南美白对虾品质对比。结果表明,南美白对虾TVB-N值、TBARS值和L^(*)值随冻藏时间的延长不断增加,硬度、弹性、咀嚼性等质构指标随冻藏时间的延长显著降低;在(-18±0.5)℃工况下,各物化指标更接近-40℃冻藏南美白对虾的品质,且温度波动幅度越大,各物化指标劣变速度越快,实用贮藏期显著降低;其中,当南美白对虾以全虾状态在(-18±8)℃的冷柜中冻藏至第108天时,TVB-N值超过国家标准规定的初步腐败界限30 mg/100 g,已经不可食用。由此可知在相同冻藏温度的情况下,减小温度波动幅度能有效抑制南美白对虾冻藏过程中的品质劣变,较好地保持其品质。

关键词：南美白对虾冻藏温度波动品质冰晶