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Study of the geomagnetic field's regional gradients in Chinese continent using three-dimensional surface Spline model

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Earth and Planetary Physics 2023年第1期7卷 74-83页

作者： Yan Feng YiJun Li JinYan Zhang Shuang Liu Abbas Nasir Ya Huang Institute of Space Weather Nanjing University of Information Science&TechnologyNanjing 210044China State Key Laboratory of Space Weather Chinese Academy of SciencesBeijing 100190China State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China School of Electronic and Optical Engineering Nanjing University of Science and TechnologyNanjing 210094China

We combined domestic ground-based and satellite magnetic measurements to create a regional three-dimensional surface Spline(3DSS)gradient model of the main geomagnetic field over the Chinese *** improve the precision of the model,we considered the data gap between the ground and satellite *** compared and analyzed the results of the Taylor polynomial,surface Spline,and CHAOS-6(the CHAMP,?rsted and SAC-C model of Earth’s magnetic field)gradient *** showed that the gradients in the south-north and east-west directions of the four models were *** 3DSS model was able to express not only gradients at different altitudes,but also average gradients inside the research *** two Spline models were able to capture more information on gradient anomalies than were the fitted *** local anomalies were observed in northern Xinjiang,Beijing,and the junction area between Jiangsu and Zhejiang,and the total intensity F decreased whereas the altitude *** gradient decreased by 21.69%in the south-north direction and increased by 11.78%in the east-west *** addition,the altitude gradient turned from negative to positive while the altitude *** Spline model and the two fitted models differed mainly in the field sources they expressed and the modeling theory.

关键词： geomagnetic field main field gradients regional model three-dimensional modeling

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Electric field-driven building blocks for introducing multiple gradients to hydrogels

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Protein & Cell 2020年第4期11卷 267-285页

作者： Gang Xu Zhaozhao Ding Qiang Lu Xiaoyi Zhang Xiaozhong Zhou Liying Xiao Guozhong Lu David L K aplan Department of Orthopedics The Second Affiliated Hospital of Soochow UniversitySuzhou 215000China Department of Bums and Plastic Surgery Engineering Research Center of the Ministry of Education for Wound Repair TechnologyThe Affiliated Hospital of Jiangnan UniversityWuxi 214041China National Engineering Laboratory for Modern Silk&Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow UniversitySuzhou 215123China Department of Orthopedics Affiliated Hospital of Xuzhou Medical UniversityLianyungang 222061China Department of Biomedical Engineering Tufts UniversityMedfordMA 02155USA

Gradient biomaterials are considered as preferable matrices for tissue engineering due to better simulation of native *** introduction of gradient cues usually needs special equipment and complex process but is only effective to limited *** of multiple gradients in the hydrogels remains ***,betasheet rich silk nanofibers(BSNF)were used as building blocks to introduce multiple gradients into different hydrogel systems through the joint action of crosslinking and electric *** blocks migrated to the anode along the electric field and gradually stagnated due to the solution-hydrogel transition of the systems,finally achieving gradient distribution of the blocks in the formed *** gradient distribution of the blocks could be tuned easily through changing different factors such as solution viscosity,which resulted in highly tunable gradient of mechanical *** blocks were also aligned under the electric field,endowing orientation gradient *** cargos could be loaded on the blocks and form gradient cues through the same crosslinking-electric field *** building blocks could be introduced to various hydrogels such as Gelatin and NIPAM,indicating the *** niches with multiple gradient cues could be achieved through the ***-based hydrogels with suitable mechanical gradients were fabricated to control the osteogenesis and ***-osteogenic gradient transition was obtained,which stimulated the ectopic osteochondral tissue regeneration in *** versatility and highly controllability of the strategy as well as multifunction of the building blocks reveal the applicability in complex tissue engineering and various interfacial tissues.

关键词： silk building blocks gradients hydrogel tissue regeneration

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Effect of heavy load carriage on cardiorespiratory responses with varying gradients and modes of carriage

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Military Medical Research 2019年第1期6卷 53-59页

作者： Subhojit Chatterjee Tirthankar Chatterjee Debojyoti Bhattacharyya Suranjana Sen Madhusudan Pal Defence Institute of Physiology and Allied Sciences Defence Research & Development Organisation Ministry of Defence

Background: The present study was undertaken to determine the effect of different uphill and downhill gradients on cardiorespiratory and metabolic responses of soldiers while carrying heavy military loads in two different ***: Eight physically fit male soldiers with a mean age 32.0±2.0 years, a mean height of 169.5±4.9 cm, and a mean weight of 63.8±8.4 kg volunteered for this study. Each volunteer completed treadmill walking trials at a speed of 3.5 km/h while carrying no external load, 31.4 kg load in a distributed mode(existing load carriage ensembles) and compact mode(new back pack) over 5 different downhill and uphill gradients(–5%, –10%, 0%, 5%, 10%) for 6 min at each gradient. During the walking trials, heart rate(HR), oxygen uptake(VO_2), respiratory frequency(RF) and energy expenditure(EE) were determined by the process of breath-by-breath gas analysis using a K4 b2 system. The average of the last 2 min data from each 6 min walking trial for each individual was subjected to statistical ***: All parameters(HR, VO_2, RF, and EE) gradually increased with the change in gradient from downhill to level to uphill. The distributed mode showed higher values compared to compact mode for all gradients, e.g., for VO_2, there was a 10.7, 7.4, 5.1, 28.2 and 18.7% increase in the distributed mode across the 5 different ***: It can be concluded from the present study that the compact mode of load carriage is more beneficial than the distributed mode in terms of cardiorespiratory responses while walking on downhill and uphill surfaces with a 31.4 kg load.

关键词： Heavy load carriage Cardio respiratory responses gradients Soldiers

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Radial Permeability Measurements for Shale Using Variable Pressure gradients

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Acta Geologica Sinica(English Edition) 2020年第2期94卷 269-279页

作者： FAN Kunkun SUN Renyuan DEREK ELS WORTH DONG Mingzhe LI Yajun YIN Congbin LI Yanchao CHEN Zhongwei WANG Chunguang State Key Laboratory of Mining Disaster Prevention and Control Shandong University of Science and TechnologyQingdao 266555China College of Energy and Mining Engineering.Shandong University of Science and Techology.Qingdao 266555 China College of Petroleum Engineering Chinese University of PetroleumQingdao 266555ShandongChina Energy and Mineral Engineering Pennsylvania State University PA 16X01USA Department of Chemical and Petroleum Engineering University of CalgaryAB T2NIN4Canada Downhole Service Company.Chuanqing Drilling Company CNPCChengdu 610051SichuanChina School of Mechanical and Mining Engineering The University of QueenslandQLD 4074Australia

Shale gas is becoming an important component of the global energy supply, with permeability a critical controlling factor for long-term gas production. Obvious deviation may exist between helium permeability determined using small pressure gradient(SPG) methods and methane permeability obtained under actual field production with variable pressure gradients(VPG). In order to more accurately evaluate the matrix permeability of shale, a VPG method using real gas(rather than He) is established to render permeability measurements that are more representative of reservoir conditions and hence response. Dynamic methane production experiments were performed to measure permeability using the annular space in the shale cores. For each production stage, boundary pressure is maintained at a constant and the gas production with time is measured on the basis of volume change history in the measuring pump. A mathematical model explicitly accommodating gas desorption uses pseudo-pressure and pseudo-time to accommodate the effects of variations in pressuredependent PVT parameters. Analytical and semi-analytical solutions to the model are obtained and discussed. These provide a convenient approach to estimate radial permeability in the core by nonlinear fitting to match the semi-analytical solution with the recorded gas production data. Results indicate that the radial permeability of the shale determined using methane is in the range of 1×10-6– 1×10-5 mD and decreases with a decrease in average pore pressure. This is contrary to the observed change in permeability estimated using helium. Bedding geometry has a significant influence on shale permeability with permeability in parallel bedding orientation larger than that in perpendicular bedding orientation. The superiority of the VPG method is confirmed by comparing permeability test results obtained from both VPG and SPG methods. Although several assumptions are used, the results obtained from the VPG method with reservoir gas are m

关键词： shale radial permeability variable pressure gradients pseudo pressure pseudo time

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Preparation of polyacrylamide gel-filled capillaries with step gradients and low UV-detection background

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Science China Chemistry 1997年第3期40卷 245-253页

作者：陈义 Institute of Chemistry Chinese Academy of SciencesBeijing 100080China

Polyacrylamide- filled capillaries with step gradients were designed and prepared with a newly established method,which is also suitable for producing other sorts of *** resulting capillaries allow the use of any UV light to approach the most sensitive detection and have the features of fast running speed and high separation efficiency In addition,the capillaries can he used continuously for more than two weeks.

关键词： gel-filled capillaries with step gradients low background polyatrylamide-filled capillaries high performance capillary gel electrophoresis size-separation of polysaccharides

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Surface-grafted block copolymer brushes with continuous composition gradients of poly(poly(ethylene glycol)-monomethacrylate) and poly(N-isopropylacrylamide)

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Science China Chemistry 2011年第2期54卷 334-342页

作者： LI LinHui WU JinDan GAO ChangYou MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310027China

Surface-grafted block copolymer brushes with continuous composition gradients containing poly(poly(ethylene glycol) monomethacrylate) (P(PEGMA)) and poly(N-isopropylacrylamide) (PNIPAAm) chains were fabricated by integration of the surface-initiated atom transfer radical polymerization (SI-ATRP) and continuous injection method. Three types of copolymer gradients were prepared: (1) a uniform P(PEGMA) layer was block copolymerized with a gradient PNIPAAm layer (PP1); (2) a gradient P(PEGMA) layer was block copolymerized with a uniform PNIPAAm layer (PP2); and (3) a gradient P(PEGMA) layer was inversely block copolymerized with a gradient PNIPAAm layer (PP3). The as-prepared gradients were characterized by ellipsometry, water contact angle and atomic force microscopy (AFM) to determine their alterations in thickness, surface wettability and morphology, confirming the gradient structures. In vitro culture of HepG2 cells was implemented on the gradient surfaces, revealing that the cells could adhere at 37 ℃ and be detached at 20 ℃. Introduction of the PEG chains as an underlying layer on the PNIPAAm grafting surfaces resulted in faster cell detachment compared with the PNIPAAm grafting surface.

关键词： gradients ATRP PNIPAAm cell attachment thermo-responsive

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Correcting the Variations of BOLD Signal Due to Susceptibility gradients and Its Application

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Journal of Computer and Communications 2019年第11期7卷 20-32页

作者： Lifang Zhao Lianjun Zhang Gang Liu Library Shandong University of Technology Zibo China School of Computer Shandong University of Technology Zibo China

Blood oxygenation level dependence signal (BOLD) for functional magnetic resonance imaging (FMRI), is the use of blood magnetization depending on the oxygenation state of hemoglobin. Susceptibility gradient can shift and skew k-space trajectories and it leads to echo time shift and BOLD sensitivity change. FMRI can be used to detect the signal, the change of the susceptibility gradient of the signal and the distortion of k space trajectory, resulting in echo time shift and BOLD sensitivity change. Using the percentage signal change (PSC) and calibration function, it can be applied to many different fields, such as age-related research. In this paper, the performance of BOLD signal change correction based on sensitivity gradient was verified by real data group calculation, and methods of further improving the calculation speed were analyzed. This paper also analyzed the performance of correcting the variations of BOLD Signal due to susceptibility gradients with real data set, and identified the computational issues that need to be improved for further research.

关键词： BOLD Signal Susceptibility gradients FMRI Percentage Signal Change

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Insect herbivory along environmental gradients

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Open Journal of Ecology 2012年第4期2卷 202-213页

作者： Nigel R. Andrew Isobel R. Roberts Sarah J. Hill Centre for Behavioural and Physiological Ecology Zoology University of New England Armidale Australia

There is a general assumption in the literature that insect herbivory increases towards the tropics, but decreases with increasing altitude. Similar generalities have been identified along other environmental gradients, such as resource, temperature, climatic and biotic gradients. However there is growing evidence in the scientific literature that such generalities are not consistent. This could be due to a number of reasons including the lack of consistency in the way herbivory is assessed such as different methodologies used by researchers, or fundamental differences in leaf damage caused by different types of insect herbivores. Here we assess 61 publications researching insect herbivory along a range of environmental gradients (both biotic and abiotic) and review the methods that researchers have used to collected their data. We found leaf chewing from samples collected in North America dominated the field and most studies assessed herbivory on a single host plant species. Thirty three percent of the studies assessed latitudinal gradients, while 10% assessed altitudinal gradients. Insect herbivory was most commonly expressed as percentage leaf damage using point herbivory. Fewer studies measured a range of different types of herbivory (such as sap sucking, leaf mining, galling, and root feeding) as leaves aged. From our synthesis, we hope that future research into insect herbivory along environmental gradients will take into account herbivory other than just leaf chewing, such as sap sucking, which may cause more damage to plants. Future research should also assess herbivory as a rate, rather than just a single point in time as damage to a young leaf may be more costly to a plant than damage to a mature or senescing leaf. Measurements of plant traits will also assist in comparing herbivory across habitats, plant species, and within species physiological variation. The true impacts that insects have on plants via herbivory along environmental gradients are still p

关键词： Insect Herbivory gradients Leaf Chewing Sap Sucking Galling Root Feeding

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Computation of magnetic gradients due to three-dimensional bodies

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Science China Earth Sciences 1997年第3期40卷 293-299页

作者：姚长利管志宁 China University of Geosciences Beijing 100083 China

The expressions of magnetic gradients due to 3-D homogeneous magnetized polyhedra are systematically derived and presented, from which the forward problem of magnetic gradients of an arbitrary shaped geological body is solved. It is shown that in the rotation of coordinate systems there is an essential difference between the transformation of magnetic fields and that of their gradients. In a 2-D coordinate system a unified transformation formula of any order gradients can be derived, but cannot in the 3-D case. The calculations of synthetic models show the correctness of the expressions of magnetic gradients.

关键词： polyhedral body magnetic gradients forward calculation coordinate transformation

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Distribution of Vascular Plants along Altitudinal gradients in Hoang Lien National Park, Vietnam

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Open Journal of Forestry 2019年第4期9卷 407-418页

作者： Mac Thi Yen Shiping Xing Hairong Han Xiaoqin Cheng Do Thi Thao Sajid Hussain Sher Shah Key Laboratory of Ministry of Cultivation and Conservation of Ministry of Education College of Forestry Beijing Forestry University Beijing China School of Economics and Management Beijing Forestry University Beijing China

The present study was conducted to examine the distributional characteristics of floral communities along the altitudinal gradients in Hoang Lien National Park (HLNP), located in Lao Cai province, Vietnam. We recorded the relatively abundant flora system with 3252 species (including 361 endemic species and 237 endangered species), belonging to 1126 genera, 230 families and 6 different phyla. Methodology of sampling, specimen collection and identification, statistical analysis are simultaneously used for investigating the complex changes of composition and richness of plant assemblages. The study results indicated the divisions in quantity and composition, especially differentiation of endemic and rare species in accordance with altitudinal gradients.

关键词： Hoang Lien National Park Altitudinal gradients Flora Diversity Distribution Endemic Plant Rare Plant Vascular Plant

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