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Mineral Chemistry and Geochemistry as Proxy for Petrogenetic Evaluation of Charnockites: Evidences from Marandahalli, Salem Block of Southern India
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作者 Sunki Amarendhar Valluri Sai Krishna Priya +1 位作者 Malintee Vittal Madabhhoshi Srinivas 《Open Journal of Geology》 CAS 2024年第11期963-987,共25页
The charnockites of Marandahalli, Dharmapuri District, Tamil Nadu India, form a part of the southern granulitic terrain in the Salem Block (SB). The charnockites are medium to coarse grained, inequigranular, with porp... The charnockites of Marandahalli, Dharmapuri District, Tamil Nadu India, form a part of the southern granulitic terrain in the Salem Block (SB). The charnockites are medium to coarse grained, inequigranular, with porphyroblastic and granophyric textures. They are composed of plagioclase feldspars (49 - 66 vol.%), K-feldspar (1 - 5 vol.%) and quartz (21 - 34 vol.%). The mafic minerals include pyroxene (2 - 7 vol.%) and biotite (1 - 12 vol.%). The accessory minerals include magnetite and apatite. Orthopyroxene compositions (MgO 16 - 22 wt.%) fall within the hypersthene series (En55.03Fs43.57Wo1.4) and yield peak metamorphic temperatures of 800˚C - 1000˚C. Biotites show K2O, MgO, FeO, TiO2, and Al2O3 concentrations consistent with magmatic formation, and Ti-in-biotite thermometry suggests temperatures of ~740˚C - 800˚C. Plagioclase compositions (An26-33) plot in the oligoclase field, while K-feldspar (Or93-99) plots in the orthoclase/microcline field. A ternary feldspar geothermometer indicates a retrograde temperature of 2 (65 - 68 wt.%), Na2O > K2O, high CaO (3 - 5 wt.%), MgO (2.5 - 4 wt.%) and Fe2O3 (2 - 6 wt.%). The concentration of V, Rb and Ni, and LREE-rich and HREE-depleted patterns of the rocks indicate low degree of partial melting. 展开更多
关键词 CHARNOCKITE Salem block Fractional Crystallization AMPHIBOLITE Marandahalli Peninsular Gneissic Complex (PGC)
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Metamorphic P-T conditions and ages of garnet-biotite schists in the Dahongshan Group from the southwestern Yangtze Block
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作者 Jun-xiao Ma Guang-shu Yang +5 位作者 Yong-feng Yan Xiao-Fei Xu Yun-hua Ren Hui Zhao Xiao-jun Zheng Yuan Qin 《Acta Geochimica》 EI CAS CSCD 2024年第4期707-718,共12页
The Dahongshan Group,situated at the southwestern margin of the Yangtze Block,represents a geological unit characterized by relatively high-grade metamorphism in the region.This paper investigates the garnet-biotite s... The Dahongshan Group,situated at the southwestern margin of the Yangtze Block,represents a geological unit characterized by relatively high-grade metamorphism in the region.This paper investigates the garnet-biotite schist from the Laochanghe Formation of the Dahongshan Group,employing an integrated approach that includes petrological analysis,phase equilibrium modeling,and zircon U-Pb dating.The schist is mainly composed of garnet,biotite,plagioclase,quartz,rutile,and ilmenite.Phase equilibrium modeling revealed the peak metamorphic conditions of 8-9 kbar and 635-675°C.By further integrating the prograde metamorphic profile of garnet and geothermobarometric results,a clockwise P-T metamorphic evolution path is constructed,which includes an increase in temperature and pressure during the prograde stage.LA-ICP-MS zircon U-Pb dating and zircon Ti thermometry constrains the post-peak metamorphic age of 831.2±7.2 Ma.Integrated with previously reported results,it is revealed that the southwestern margin of the Yangtze Block experienced a large-scale regional metamorphism during the Neoproterozoic(890-750 Ma),which is related to the collisional orogenic process.This may be associated with the late-stage assembly of the Rodinia supercontinent or with local compression and subduction processes during the breakup of the Rodinia supercontinent. 展开更多
关键词 Southwestern Yangtze block dahongshan Group Phase equilibrium modeling Zircon U-Pb dating Neoproterozoic metamorphism
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Databases of 2D material-substrate interfaces and 2D charged building blocks
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作者 邓俊 潘金波 杜世萱 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期34-38,共5页
Discovery of materials using“bottom-up”or“top-down”approach is of great interest in materials science.Layered materials consisting of two-dimensional(2D)building blocks provide a good platform to explore new mater... Discovery of materials using“bottom-up”or“top-down”approach is of great interest in materials science.Layered materials consisting of two-dimensional(2D)building blocks provide a good platform to explore new materials in this respect.In van der Waals(vdW)layered materials,these building blocks are charge neutral and can be isolated from their bulk phase(top-down),but usually grow on substrate.In ionic layered materials,they are charged and usually cannot exist independently but can serve as motifs to construct new materials(bottom-up).In this paper,we introduce our recently constructed databases for 2D material-substrate interface(2DMSI),and 2D charged building blocks.For 2DMSI database,we systematically build a workflow to predict appropriate substrates and their geometries at substrates,and construct the 2DMSI database.For the 2D charged building block database,1208 entries from bulk material database are identified.Information of crystal structure,valence state,source,dimension and so on is provided for each entry with a json format.We also show its application in designing and searching for new functional layered materials.The 2DMSI database,building block database,and designed layered materials are available in Science Data Bank at https://doi.org/10.57760/sciencedb.j00113.00188. 展开更多
关键词 2D material-substrate interfaces charged building block database functional-oriented materials design layered materials density functional theory
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Sliding behaviors of the trapezoidal roof rock block under a lateral dynamic disturbance
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作者 Feng Dai Wancheng Zhu +2 位作者 Min Ren Shunchuan Wu Leilei Niu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期741-760,共20页
The surrounding rock of underground space is always affected by external dynamic disturbance from the side position,such as blasting vibration from a stope at the same level or seismic waves from adjacent strata.A ser... The surrounding rock of underground space is always affected by external dynamic disturbance from the side position,such as blasting vibration from a stope at the same level or seismic waves from adjacent strata.A series of laboratory tests,numerical simulations and theoretical analyses were carried out in this study to disclose the sliding mechanism of roof rock blocks under lateral disturbance.Firstly,the experiments on trapezoidal key block under various clamping loads and disturbance were conducted,followed by numerical simulations using the fast Lagrangian analysis of continua(FLAC3D).Then,based on the conventional wave propagation model and the classical shear-slip constitutive model,a theoretical model was proposed to capture the relative displacement between blocks and the sliding displacement of the key block.The results indicate that the sliding displacement of the key block increased linearly with the disturbance energy and decreased exponentially with the clamping load when the key block was disturbed to slide(without instability).Meanwhile,when the key block was disturbed to fall,two types of instability process may appear as immediate type or delayed type.In addition,the propagation of stress waves in the block system exhibited obvious low-velocity and lowfrequency characteristics,resulting in the friction reduction effect appearing at the contact interface,which is the essential reason for the sliding of rock blocks.The results can be applied to practical underground engineering and provide valuable guidance for the early detection and prevention of rockfalling disasters. 展开更多
关键词 Lateral dynamic disturbance Trapezoidal rock block system Low-velocity and low-frequency wave Friction reduction effect Instability mode
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Factors influencing agitation during anesthesia recovery after laparoscopic hernia repair under total inhalation combined with caudal block anesthesia
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作者 Yun-Feng Zhu Fan-Yan Yi +4 位作者 Ming-Hui Qin Ji Lu Hao Liang Sen Yang Yu-Zheng Wei 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第11期3499-3510,共12页
BACKGROUND Laparoscopic hernia repair is a minimally invasive surgery,but patients may experience emergence agitation(EA)during the post-anesthesia recovery period,which can increase pain and lead to complications suc... BACKGROUND Laparoscopic hernia repair is a minimally invasive surgery,but patients may experience emergence agitation(EA)during the post-anesthesia recovery period,which can increase pain and lead to complications such as wound reopening and bleeding.There is limited research on the risk factors for this agitation,and few effective tools exist to predict it.Therefore,by integrating clinical data,we have developed nomograms and random forest predictive models to help clinicians predict and potentially prevent EA.AIM To establish a risk nomogram prediction model for EA in patients undergoing laparoscopic hernia surgery under total inhalation combined with sacral block anesthesia.METHODS Based on the clinical information of 300 patients who underwent laparoscopic hernia surgery in the Nanning Tenth People’s Hospital,Guangxi,from January 2020 to June 2023,the patients were divided into two groups according to their sedation-agitation scale score,i.e.,the EA group(≥5 points)and the non-EA group(≤4 points),during anesthesia recovery.Least absolute shrinkage and selection operator regression was used to select the key features that predict EA,and incorporating them into logistic regression analysis to obtain potential pre-dictive factors and establish EA nomogram and random forest risk prediction models through R software.RESULTS Out of the 300 patients,72 had agitation during anesthesia recovery,with an incidence of 24.0%.American Society of Anesthesiologists classification,preoperative anxiety,solid food fasting time,clear liquid fasting time,indwelling catheter,and pain level upon awakening are key predictors of EA in patients undergoing laparoscopic hernia surgery with total intravenous anesthesia and caudal block anesthesia.The nomogram predicts EA with an area under the receiver operating characteristic curve(AUC)of 0.947,a sensi-tivity of 0.917,and a specificity of 0.877,whereas the random forest model has an AUC of 0.923,a sensitivity of 0.912,and a specificity of 0.877.Delong’s test shows no significant difference in AUC between the two models.Clinical decision curve analysis indicates that both models have good net benefits in predicting EA,with the nomogram effective within the threshold of 0.02 to 0.96 and the random forest model within 0.03 to 0.90.In the external model validation of 50 cases of laparoscopic hernia surgery,both models predicted EA.The nomogram model had a sensitivity of 83.33%,specificity of 86.84%,and accuracy of 86.00%,while the random forest model had a sensitivity of 75.00%,specificity of 78.95%,and accuracy of 78.00%,suggesting that the nomogram model performs better in predicting EA.CONCLUSION Independent predictors of EA in patients undergoing laparoscopic hernia repair with total intravenous anesthesia combined with caudal block include American Society of Anesthesiologists classification,preoperative anxiety,duration of solid food fasting,duration of clear liquid fasting,presence of an indwelling catheter,and pain level upon waking.The nomogram and random forest models based on these factors can help tailor clinical decisions in the future. 展开更多
关键词 Inhalation anesthesia Sacral block anesthesia Laparoscopic hernia surgery Agitation during recovery period NOMOGRAM Surgical outcomes Postoperative complications
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Enhancing postoperative pain control by surgically-initiated rectus sheath block in abdominal aortic aneurysm open repair: A case report
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作者 Kuan-Hua Chen Ming-Yuan Kang +2 位作者 Yi-Ting Chang Sheng-Yang Huang Yung-Szu Wu 《World Journal of Clinical Cases》 SCIE 2025年第6期41-47,共7页
BACKGROUND Abdominal aortic aneurysm(AAA)repair often involves significant postoperative pain,traditionally managed with systemic opioids,which can cause undesirable side effects.This case report explores the novel us... BACKGROUND Abdominal aortic aneurysm(AAA)repair often involves significant postoperative pain,traditionally managed with systemic opioids,which can cause undesirable side effects.This case report explores the novel use of a surgically-initiated rectus sheath block with a catheter-over-needle assembly for pain management in AAA repair.CASE SUMMARY A 67-year-old female with hypertension and previous aortic dissection underwent elective open repair of an infrarenal AAA,which had grown from 3.4 cm to 4.3 cm over 14 months.A rectus sheath block was initiated surgically for postoperative pain control.The patient reported low pain scores and did not require systemic intravenous opioids,enabling early ambulation and discharge on postoperative day seven without complications.By preventing complications of systemic opi-oids,the method indicating a promising direction for postoperative pain management in major vascular surgeries.CONCLUSION Surgically-initiated rectus sheath block as a valuable tool for managing postoperative pain in AAA repair. 展开更多
关键词 Abdominal aortic aneurysm Postoperative pain management Rectus sheath block Surgical anesthesia Opioid-sparing techniques Case report
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安氏Ⅱ类错[牙合]畸形佩戴Twin-block矫治器时上颌骨的应力分布
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作者 李帅 刘桦 +3 位作者 商永慧 刘义琮 赵启航 刘文 《中国组织工程研究》 CAS 北大核心 2025年第5期881-887,共7页
背景:Twin-block矫治器常用于安氏Ⅱ类错[牙合]畸形的矫治,其刺激下颌骨生长的作用机制已得到许多研究证实,但对上颌骨生长的影响尚不清楚。目的:通过有限元法分析安氏Ⅱ类错[牙合]畸形患者佩戴Twin-block矫治器时上颌骨复合体、周围骨... 背景:Twin-block矫治器常用于安氏Ⅱ类错[牙合]畸形的矫治,其刺激下颌骨生长的作用机制已得到许多研究证实,但对上颌骨生长的影响尚不清楚。目的:通过有限元法分析安氏Ⅱ类错[牙合]畸形患者佩戴Twin-block矫治器时上颌骨复合体、周围骨缝及上颌牙列的应力分布。方法:选择在山东省康复大学青岛医院/青岛市市立医院口腔正畸科进行正畸治疗的安氏Ⅱ类错[牙合]畸形患者1例,测量患者佩戴Twin-block矫治器时的咬合力数据,采集其锥形束CT数据,建立包含上颌骨复合体、周边各骨缝、Twin-block矫治器及上颌牙列在内的有限元模型,通过ABAQUS软件模拟患者戴入Twin-block时上颌骨、骨缝及上颌牙列的应力分布与位移。结果与结论:①上颌前牙受到的等效应力明显小于后牙,两侧牙齿的最大等效应力分别为4.7975 MPa和8.7161 MPa,均位于第一前磨牙处;最大位移呈现在两侧上颌切牙处,分别为0.0805 mm和0.0810 mm;②骨缝的最大等效应力为1.284 MPa,主要集中在两侧翼腭缝及额颌缝,其余骨缝受力情况几乎无差异;骨缝的最大位移为0.07 mm,其中翼腭缝的位移量最大,其次是额颌缝;③上颌骨复合体受到的最大等效应力为27.18 MPa,主要集中在上颌骨前面梨状孔两侧、鼻额缝周边及颚骨后部翼腭缝附近;上颌骨的最大位移值为0.07 mm,主要集中于上颌牙槽骨;④结果显示,咬合力通过Twin-block矫治器作用于上颌骨复合体,导致上颌骨顺时针旋转、牙合平面变陡,应采取相应措施补偿这种趋势,例如建牙合过程中考虑上颌磨牙伸长、下颌磨牙压低,不仅能够将牙合平面整平,同时有利于下颌前伸,这将进一步提高Ⅱ类错[牙合]正畸治疗效果。 展开更多
关键词 错牙合畸形 组织构建 骨组织工程 TWIN-block矫治器 功能矫治 有限元分析
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Normal faulting and its role in the drainage divide migration in the Karιncalιda?region,Menderes Massif,Western Türkiye
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作者 TOPAL Savaş IRFAN Mohammad 《Journal of Mountain Science》 2025年第1期312-323,共12页
Drainage divide migration refers to the shifting boundaries between adjacent drainage basins over time,driven by processes such as tectonic uplift,differential erosion,stream capture,and lithological variations.This p... Drainage divide migration refers to the shifting boundaries between adjacent drainage basins over time,driven by processes such as tectonic uplift,differential erosion,stream capture,and lithological variations.This phenomenon has a significant impact on water flow patterns and basin extents,serving as an indicator of the landscape's response to active tectonic forces.One of the key drivers of divide migration is asymmetric uplift,which causes divides to shift from areas of lower uplift to regions experiencing higher uplift.Drainage divides are inherently dynamic,evolving over time as drainage networks develop and adjust to changing conditions.This study focuses on the migration of the main drainage divide along Karιncalιda?,located between Bozdo?an and Karacasu.It employs geomorphic analyses using metrics such as the normalized steepness index(ksn),Chi(χ),and Gilbert metrics.The main divide is categorized into four segments(D1–D4),with the Karacasu Fault,situated along the mountain's north-eastern boundary,identified as the primary factor influencing divide dynamics.Secondary factors include the relatively low elevation of Karιncalιda?,uniform lithology,and consistent rainfall patterns across the region.The results indicate that the main divide is currently stable,suggesting a balance between uplift and erosion.However,higherχvalues in the D4 segment suggest that future erosion may dominate,potentially causing the divide to migrate toward the Bozdo?an Basin.These findings highlight the dynamic nature of drainage divides and the complex interplay of tectonic,erosional,and lithological processes that shape their evolution.Continued monitoring and advanced geomorphic analysis are essential for understanding the long-term stability of the divide and its response to future tectonic activity and erosional modifications. 展开更多
关键词 Drainage divide migration Gilbert metrics Karıncalıdağ Karacasu Fault
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Thermo-Hydraulic Performances of Microchannel Heat Sinks with Different Types of Perforated Rectangular Blocks
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作者 Heng Zhao Honghua Ma +4 位作者 Hui Liu Xiang Yan Huaqing Yu Yongjun Xiao Xiao Xiao 《Fluid Dynamics & Materials Processing》 2025年第1期87-105,共19页
The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areex... The behavior of single-phase flow and conjugate heat transfer in micro-channel heat sinks(MCHS)subjected to auniform heat flux is investigated by means of numerical simulations.Various geometrical configurations areexamined,particularly,the combinations of rectangular solid and perforated blocks,used to create a disturbancein the flow.The analysis focuses on several key aspects and related metrics,including the temperature distribution,the mean Fanning friction factor,the pressure drop,the Nusselt number,and the overall heat transfer coefficientacross a range of Reynolds numbers(80–870).It is shown that the introduction of such blocks significantlyenhances the heat transfer performances of the MCHS compared to the straight-through flow channel.Specifically,a case is found where the Nusselt number increases by 2.3 times relative to the reference case.The integrationof perforated blocks facilitates the generation of vorticity within the channel,promoting the mixing of coldand hot fluids.Notably,MCHS incorporating perforated rectangular blocks exhibit more pronounced heat transferbenefits at Reynolds numbers smaller than 400. 展开更多
关键词 Micro-channel heat sink(MCHS) perforated rectangular blocks thermal performance convection heat transfer
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P-block基金属原子在TiO_(2)(110)表面的吸附及扩散性质研究
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作者 丁雅妮 郭梦雨 +3 位作者 王博涵 贾晨怡 王美娟 史金磊 《原子与分子物理学报》 CAS 北大核心 2025年第6期17-21,共5页
基于密度泛函理论的第一性原理计算方法,我们系统研究了p-block金属原子(Sn,Sb,Bi和Te)在TiO_(2)(110)表面上的吸附及扩散行为.计算结果表明Sn,Sb及Bi金属原子在TiO_(2)(110)表面上具有较大的吸附能和较高的扩散势垒,倾向于形成分散的p-... 基于密度泛函理论的第一性原理计算方法,我们系统研究了p-block金属原子(Sn,Sb,Bi和Te)在TiO_(2)(110)表面上的吸附及扩散行为.计算结果表明Sn,Sb及Bi金属原子在TiO_(2)(110)表面上具有较大的吸附能和较高的扩散势垒,倾向于形成分散的p-block单原子,然而对于Te金属原子,由于其与衬底结合能相对较弱且扩散势垒较低而更倾向于形成团簇,该研究结果有助于为实验上构建基于p-block的金属单原子催化剂提供理论依据. 展开更多
关键词 p-block单原子催化剂 吸附及扩散势垒 第一性原理计算
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基于分布式光纤声波传感技术(DAS)的地下管道、隧道侵入监测方法研究
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作者 曹鹏涛 韦义师 +1 位作者 李轶 吴奇 《物探化探计算技术》 2025年第1期104-116,共13页
地铁隧道沿线入侵事件造成地铁线路变形破坏,地下管道沿线人为破坏、野蛮施工引发安全事故与财产损失,有必要在隧道沿线与地下管道沿线进行监测与预警,及时发现入侵破坏处,进行阻止或者及时开展补救维修降低事故损失。分布式光纤声波传... 地铁隧道沿线入侵事件造成地铁线路变形破坏,地下管道沿线人为破坏、野蛮施工引发安全事故与财产损失,有必要在隧道沿线与地下管道沿线进行监测与预警,及时发现入侵破坏处,进行阻止或者及时开展补救维修降低事故损失。分布式光纤声波传感(DAS)技术,具有动态在线监测、大范围密集测量、方便布设免维护等独特优势。通过在地下轨道交通、地下管道沿线布设分布式光纤,采用DAS技术对光纤沿线外界扰动进行监测,针对传统的时频分析算法不适用分析DAS信号,笔者采用基于优化S变换的时频分析方法,将DAS信号变换到时间-频率域,根据不同振动信号的时频特征差异,在时间频率域对不同振动信号进行分类识别、精确定位,并对超过阈值的侵入信号进行预警。通过数值模拟分析以及实际地铁线路区间DAS监测实验,结果表明基于优化S变换的DAS监测方法技术,对不同主频振动信号具有较强识别监测能力,并且具有监测距离长、响应及时等特点,可以实现长距离、大范围密集测量、动态、实时监测预警,为城市地下管道、地下轨道交通沿线监测提供了一种快速准确的解决方案。 展开更多
关键词 分布式光纤声波传感(daS) 监测预警 时频分析
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Database-oriented storage based on LMDB and linear octree for massive block model 被引量:6
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作者 毕林 赵辉 贾明涛 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第9期2462-2468,共7页
Data organization requires high efficiency for large amount of data applied in the digital mine system. A new method of storing massive data of block model is proposed to meet the characteristics of the database, incl... Data organization requires high efficiency for large amount of data applied in the digital mine system. A new method of storing massive data of block model is proposed to meet the characteristics of the database, including ACID-compliant, concurrency support, data sharing, and efficient access. Each block model is organized by linear octree, stored in LMDB(lightning memory-mapped database). Geological attribute can be queried at any point of 3D space by comparison algorithm of location code and conversion algorithm from address code of geometry space to location code of storage. The performance and robustness of querying geological attribute at 3D spatial region are enhanced greatly by the transformation from 3D to 2D and the method of 2D grid scanning to screen the inner and outer points. Experimental results showed that this method can access the massive data of block model, meeting the database characteristics. The method with LMDB is at least 3 times faster than that with etree, especially when it is used to read. In addition, the larger the amount of data is processed, the more efficient the method would be. 展开更多
关键词 block model linear octree lightning memory-mapped database mass data access digital mine etree
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东海OBN和三维DAS-VSP数据的联合采集与处理方法研究 被引量:1
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作者 张少华 苟量 +8 位作者 余刚 刘海波 张昊 曹中林 陈沅忠 何光明 吴俊军 王熙明 王艳华 《石油物探》 CSCD 北大核心 2024年第1期30-44,共15页
近年来,光纤传感技术已经应用于地面地震数据、海洋地震数据、井中地震数据和井地联合地震数据的采集,推动了光纤传感技术在地球物理特别是地震数据采集中的应用。井地或井海联合地震勘探是陆地或海洋三维地震与三维DAS-VSP勘探相结合... 近年来,光纤传感技术已经应用于地面地震数据、海洋地震数据、井中地震数据和井地联合地震数据的采集,推动了光纤传感技术在地球物理特别是地震数据采集中的应用。井地或井海联合地震勘探是陆地或海洋三维地震与三维DAS-VSP勘探相结合形成的三维立体地震勘探方法,利用井海联采的三维DAS-VSP数据,可以获得地下井周围准确的时深关系、地层速度、反褶积算子、球面扩散补偿因子、吸收衰减因子、各向异性参数和井筒周围的高分辨率构造成像,这些参数可以基于井驱处理提高陆地或海洋三维地震数据的处理质量。在中国东海某OBN数据勘探中首次开展了井下套管内铠装光缆同步采集的三维DAS-VSP数据的处理方法研究以及成像处理。首先,采用常规的三维VSP数据成像处理技术对三维DAS-VSP数据进行常规处理,具体处理流程包括:观测系统定义、预处理、初至拾取、静校正、振幅补偿、反褶积、波场分离、速度分析与建模和利用上行反射波进行井周围地层的构造成像;然后,再根据海上三维DAS-VSP数据下行多次波的特点,研发了海上三维DAS-VSP数据的下行多次波成像技术,扩展了三维DAS-VSP数据成像范围,提高了三维DAS-VSP数据成像的整体质量。与本工区早期的三维OBC数据成像结果相比,本次三维DAS-VSP数据的下行多次波成像结果表明,井周围三维构造成像质量得到了显著改进,大幅度扩展了成像范围;新采集的OBN数据和三维DAS-VSP数据的成像结果展示了更为详细和较高分辨率的构造成像,基于新的成像资料,对储层顶部和储层内流体的识别与追踪变得更加容易和清晰。井海联采技术生产效率高且成本低,既能快速获得三维DAS-VSP数据及成像,还能对三维海洋地震数据进行井驱提高分辨率处理。此外,三维OBN或OBC数据和三维DAS-VSP数据还能够进行融合处理,实现井地或井海同步采集数据的联合偏移成像,可以大幅度提高三维海洋地震数据的成像品质,值得在有条件的地方推广应用。 展开更多
关键词 光纤 分布式 daS-VSP OBN OBC 联采 多次波偏移
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基于DA-VMD联合小波阈值的排种器田间振动信号去噪方法
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作者 刘正道 马壮红 +3 位作者 张军昌 闫小丽 黄玉祥 张志强 《农业机械学报》 EI CAS CSCD 北大核心 2024年第11期262-272,共11页
播种机作业过程中排种器会受到非平稳随机振动,对排种性能产生较大的影响,对振动信号采集和分析具有重要意义,而田间振动信号采集过程中受到诸多噪声干扰,难以从中获取有效的信息。本文提出了一种结合蜻蜓算法(Dragonfly algorithm,DA)... 播种机作业过程中排种器会受到非平稳随机振动,对排种性能产生较大的影响,对振动信号采集和分析具有重要意义,而田间振动信号采集过程中受到诸多噪声干扰,难以从中获取有效的信息。本文提出了一种结合蜻蜓算法(Dragonfly algorithm,DA)、变分模态分解(Variational mode decomposition,VMD)和小波阈值的去噪方法,可通过不断迭代更新蜻蜓个体位置和速度,寻找使得VMD分解效果最优的参数组合。以仿真得到的时域随机路面信号为初始信号,分别采用DA-VMD联合小波阈值、小波阈值去噪、经验模态分解(Empirical mode decomposition,EMD)、VMD和小波联合EMD方法对其进行去噪处理,结果表明本文所提出的去噪方法对非平稳随机振动信号去噪效果更优,去噪后信噪比、均方根和相关系数分别为21.570、0.094和0.833。采集田间播种过程不同地表和作业速度下排种器振动信号,并采用DA-VMD联合小波阈值去噪方法对其进行去噪处理,以平滑度、信号能量比和噪声模为评价指标分析去噪效果,结果表明本文所提出方法去噪后信号更加平滑,信号能量比和噪声模更高,且在不同工况条件下均具有较好的去噪效果。 展开更多
关键词 排种器 振动 去噪 da-VMD 小波阈值
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基于“脑肠轴理论”探讨龟羚帕安丸对PD大鼠纹状体DA及血清CCK、VIP水平影响的研究
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作者 常学辉 张良芝 +2 位作者 陈帅杰 王冬莲 张创业 《四川中医》 2024年第1期80-83,共4页
目的:基于“脑肠轴理论”探讨龟羚帕安丸对PD大鼠纹状体裂解液多巴胺(Dopamine,DA)、血清胆囊收缩素(cholecystokinin,CCK)及血管活性肠肽(vasoactive intestinal peptide,VIP)水平的影响。方法:采用6-羟基多巴胺注射法制作PD大鼠模型,... 目的:基于“脑肠轴理论”探讨龟羚帕安丸对PD大鼠纹状体裂解液多巴胺(Dopamine,DA)、血清胆囊收缩素(cholecystokinin,CCK)及血管活性肠肽(vasoactive intestinal peptide,VIP)水平的影响。方法:采用6-羟基多巴胺注射法制作PD大鼠模型,随机分为模型组、西药组、中药高、中、低剂量组,每组15只,另设15只假手术组。模型组及假手术组给予等容积生理盐水灌胃,其余组给予相应药物灌胃,连续给药4周。酶联免疫吸附测定法(ELISA)检测纹状体裂解液DA及血清CCK、VIP水平。结果:模型组大鼠纹状体DA、血清CCK及VIP水平显著降低;中药各剂量组、西药组大鼠纹状体DA、血清CCK及VIP水平明显均增加(P<0.01)。结论:龟羚帕安丸具有明显神经保护作用,作用机制与激活脑肠轴、增加血清CCK及VIP水平、增加中脑黑质纹状体DA的水平、发挥改善肠道功能作用有关。 展开更多
关键词 帕金森病 龟羚帕安丸 多巴胺 胆囊收缩素 血管活性肠肽
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采用非稳相偏振滤波的DAS-VSP数据P/S波分离方法及其应用
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作者 王腾飞 程玖兵 +3 位作者 孟涛 曹中林 胡善政 段鹏飞 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2024年第7期2761-2772,共12页
分布式光纤声学传感(DAS)因成本低、易布设以及高密度采样等优势正成为重要的地震观测技术,尤其是越来越多地与垂直地震剖面(VSP)结合,用于主动地震勘探或被动地震监测.DAS传感器通过感知弹性波场产生的轴向应变或应变速率来观测地震波... 分布式光纤声学传感(DAS)因成本低、易布设以及高密度采样等优势正成为重要的地震观测技术,尤其是越来越多地与垂直地震剖面(VSP)结合,用于主动地震勘探或被动地震监测.DAS传感器通过感知弹性波场产生的轴向应变或应变速率来观测地震波场振动.然而,目前单分量DAS-VSP数据未完整地记录地下弹性波场的三维矢量振动信号,因此如何从中分离出P波或S波用于后续地震成像与参数反演是重要且很有挑战的课题.以弹性波传播理论为基础,本文根据P波和S波的频散关系估算接收点处各自的偏振方向,通过随频率和空间位置变化的偏振滤波实现DAS-VSP数据的P/S波分离.理论模型合成数据与东海实际DAS-VSP数据实验结果表明,该方法能有效地将P波和S波信号从单分量DAS-VSP数据中分离出来,可为后续纵横波速度反演、PP与PS波成像提供关键的数据预条件处理. 展开更多
关键词 分布式光纤声学传感(daS) VSP P/S波分离 偏振投影 非稳相滤波
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分组密码算法uBlock积分攻击的改进
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作者 王晨 崔佳敏 +1 位作者 李木舟 王美琴 《电子与信息学报》 EI CAS CSCD 北大核心 2024年第5期2149-2158,共10页
积分攻击是由Daemen等人(doi:10.1007/BFb0052343)于1997年提出的一种密码分析方法,是继差分分析和线性分析之后最有效的密码分析方法之一。作为2018年全国密码算法设计竞赛分组算法的获胜算法,uB-lock抵抗积分攻击的能力受到较多的关... 积分攻击是由Daemen等人(doi:10.1007/BFb0052343)于1997年提出的一种密码分析方法,是继差分分析和线性分析之后最有效的密码分析方法之一。作为2018年全国密码算法设计竞赛分组算法的获胜算法,uB-lock抵抗积分攻击的能力受到较多的关注。为了重新评估uBlock家族密码算法抵抗积分攻击的安全性,该文利用单项式传播技术,结合混合整数线性规划(MILP)工具搜索积分区分器,并利用部分和技术进行密钥恢复攻击。对于uBlock-128/128和uBlock-128/256,基于搜索到的9轮积分区分器分别进行了首个11轮和12轮攻击,数据复杂度为2~(127)选择明文,时间复杂度分别为2~(127.06)和2~(224)次加密,存储复杂度分别为2~(44.58)和2~(138)字节;对于uBlock-256/256,基于搜索到的10轮积分区分器进行了首个12轮攻击,数据复杂度为2~(253)选择明文,时间复杂度为2~(253.06)次加密,存储复杂度为2~(44.46)字节。与之前uBlock的最优积分攻击结果相比,uBlock-128/128和uBlock-256/256的攻击轮数分别提高2轮,uBlock-128/256的攻击轮数提高3轮。本文的攻击说明,uBlock针对积分攻击依然有足够的安全冗余。 展开更多
关键词 密码分析 分组密码 ublock 积分攻击
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Long-term anodal block stimulation at sacral anterior roots promoted recovery of neurogenic bladder function in a rabbit model of complete spinal cord injury 被引量:6
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作者 Xiaoran Wang Qi Gao +11 位作者 Xiaoyu Yang Weihua Wang Xinquan Gu Guifeng Liu Peng Yan Ge Gao Xin Yu Yongjie Wang Jihu Lian Chaoling Shi Yao Wang Li Fan 《Neural Regeneration Research》 SCIE CAS CSCD 2012年第5期352-358,共7页
A complete spinal cord injury model was established in experimental rabbits using the spinal cord clip compression method. Urodynamic examination was performed 2 weeks later to determine neurogenic bladder status. The... A complete spinal cord injury model was established in experimental rabbits using the spinal cord clip compression method. Urodynamic examination was performed 2 weeks later to determine neurogenic bladder status. The rabbits were treated with anodal block stimulation at sacral anterior roots for 4 weeks. Electrical stimulation of sacral anterior roots improved urodynamic parameters of neurogenic bladder in rabbit models of complete spinal cord injury, effectively promoted urinary function, and relieved urinary retention. Immunohistochemistry results showed that a balance was achieved among expression of muscarinic receptor subunits M2, M3, ATP-gated ion channel P2X3 receptors, and 132-adrenergic receptor, and nerve growth factor expression decreased. These results suggested that long-term sacral anterior root stimulation of anodal block could'be used to treat neurogenic bladder in a rabbit model of complete spinal cord injury. 展开更多
关键词 anode block electrical stimulation immunohistochemistry neurogenic bladder URODYNAMICS spinal cord injury
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基于SDRS数据的钻石DA20飞机故障分析及处理
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作者 孙一 《机电信息》 2024年第16期47-49,53,共4页
基于使用困难报告系统(SDRS)对钻石DA20飞机的故障数据进行分析。基于SDRS系统收集到的数据,结合故障分类方法,对钻石DA20飞机的不同故障进行研究,并提出相应的解决措施,有利于提高钻石DA20飞机机队的可靠性和安全性。
关键词 SDRS da20飞机 故障 数据
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Present-day crustal deformation around Kalpin block,Xinjiang,China,observed by InSAR 被引量:3
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作者 Liu Liwei Ji Lingyun Yang Xiaodong 《Geodesy and Geodynamics》 2014年第3期23-28,共6页
Due to the effect of the collision between the Indian plate and Eurasian plate, Pamirs is constantly moving to the north. Under the interaction among multiple tectonic blocks, strong earthquakes often occurred around ... Due to the effect of the collision between the Indian plate and Eurasian plate, Pamirs is constantly moving to the north. Under the interaction among multiple tectonic blocks, strong earthquakes often occurred around the Kalpin block which is located in western Tianshan of Chinese continent. In this paper, we used Intefferometric Synthetic Aperture Radar (InSAR) technique and adopted stacking algorithm to achieve the present-day crustal deformation field of the Kalpin block region based on 38 Envisat ASAR images. The results show that the deformation in radar line of sight around Kalpin block is mainly compressive between south and north with magnitude 1-1.5 mm/a. Displacement decreases gradually from northwest to southeast, which is consistent with the deformation characteristics shown in Tianshan, i.e. crust is gradually shortening from west to east detected by the GPS observations. Also, the Piqiang fault zone is uplifting. And there is an obvious displacement difference between the two sides of the Aozigeertawu fault. 展开更多
关键词 INSAR STACKING Kalpin block deformation velocity
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