期刊文献+
共找到148,952篇文章
< 1 2 250 >
每页显示 20 50 100
Coexistence of Dirac and Weyl points in non-centrosymmetric semimetal NbIrTe_(4)
1
作者 刘清馨 付阳 +4 位作者 丁鹏飞 马欢 郭朋杰 雷和畅 王善才 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期146-151,共6页
Using angle-resolved photoemission spectroscopy and density functional theory calculations methods,we investigate the electronic structures and topological properties of ternary tellurides NbIrTe_(4),a candidate for t... Using angle-resolved photoemission spectroscopy and density functional theory calculations methods,we investigate the electronic structures and topological properties of ternary tellurides NbIrTe_(4),a candidate for type-II Weyl semimetal.We demonstrate the presence of several Fermi arcs connecting their corresponding Weyl points on both termination surfaces of the topological material.Our analysis reveals the existence of Dirac points,in addition to Weyl points,giving both theoretical and experimental evidences of the coexistence of Dirac and Weyl points in a single material.These findings not only confirm NbIrTe_(4) as a unique topological semimetal but also open avenues for exploring novel electronic devices based on its coexisting Dirac and Weyl fermions. 展开更多
关键词 Fermi arc Weyl point Dirac point angle-resolved photoemission spectroscopy
下载PDF
Exceptional points and quantum dynamics in a non-Hermitian two-qubit system
2
作者 张益玺 张振涛 +2 位作者 杨震山 魏晓志 梁宝龙 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期212-218,共7页
We study the exceptional-point(EP) structure and the associated quantum dynamics in a system consisting of a non-Hermitian qubit and a Hermitian qubit. We find that the system possesses two sets of EPs, which divide t... We study the exceptional-point(EP) structure and the associated quantum dynamics in a system consisting of a non-Hermitian qubit and a Hermitian qubit. We find that the system possesses two sets of EPs, which divide the systemparameter space into PT-symmetry unbroken, partially broken and fully broken regimes, each with distinct quantumdynamics characteristics. Particularly, in the partially broken regime, while the PT-symmetry is generally broken in the whole four-dimensional Hilbert space, it is preserved in a two-dimensional subspace such that the quantum dynamics in the subspace are similar to those in the PT-symmetry unbroken regime. In addition, we reveal that the competition between the inter-qubit coupling and the intra-qubit driving gives rise to a complex pattern in the EP variation with system parameters. 展开更多
关键词 non-Hermitian system exceptional point PT-SYMMETRY
下载PDF
Prediction of collapse process and tipping points for mutualistic and competitive networks with k-core method
3
作者 段东立 毕菲菲 +3 位作者 李思凡 吴成星 吕长春 蔡志强 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期173-180,共8页
Ecosystems generally have the self-adapting ability to resist various external pressures or disturbances,which is always called resilience.However,once the external disturbances exceed the tipping points of the system... Ecosystems generally have the self-adapting ability to resist various external pressures or disturbances,which is always called resilience.However,once the external disturbances exceed the tipping points of the system resilience,the consequences would be catastrophic,and eventually lead the ecosystem to complete collapse.We capture the collapse process of ecosystems represented by plant-pollinator networks with the k-core nested structural method,and find that a sufficiently weak interaction strength or a sufficiently large competition weight can cause the structure of the ecosystem to collapse from its smallest k-core towards its largest k-core.Then we give the tipping points of structure and dynamic collapse of the entire system from the one-dimensional dynamic function of the ecosystem.Our work provides an intuitive and precise description of the dynamic process of ecosystem collapse under multiple interactions,and provides theoretical insights into further avoiding the occurrence of ecosystem collapse. 展开更多
关键词 complex networks tipping points dimension reduction k-core
下载PDF
Triple points and phase transitions of D-dimensional dyonic Ad S black holes with quasitopological electromagnetism in Einstein–Gauss–Bonnet gravity
4
作者 牟平辉 蒋青权 +1 位作者 何柯腱 李国平 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期272-287,共16页
By considering the negative cosmological constant Λ as a thermodynamic pressure, we study the thermodynamics and phase transitions of the D-dimensional dyonic Ad S black holes(BHs) with quasitopological electromagnet... By considering the negative cosmological constant Λ as a thermodynamic pressure, we study the thermodynamics and phase transitions of the D-dimensional dyonic Ad S black holes(BHs) with quasitopological electromagnetism in Einstein–Gauss–Bonnet(EGB) gravity. The results indicate that the small/large BH phase transition that is similar to the van der Waals(vdW) liquid/gas phase transition always exists for any spacetime dimensions. Interestingly, we then find that this BH system exhibits a more complex phase structure in 6-dimensional case that is missed in other dimensions.Specifically, it shows for D = 6 that we observed the small/intermediate/large BH phase transitions in a specific parameter region with the triple point naturally appeared. Moreover, when the magnetic charge turned off, we still observed the small/intermediate/large BH phase transitions and triple point only in 6-dimensional spacetime, which is consistent with the previous results. However, for the dyonic Ad S BHs with quasitopological electromagnetism in Einstein–Born–Infeld(EBI) gravity, the novel phase structure composed of two separate coexistence curves observed by Li et al. [Phys. Rev. D105 104048(2022)] disappeared in EGB gravity. This implies that this novel phase structure is closely related to gravity theories, and seems to have nothing to do with the effect of quasitopological electromagnetism. In addition, it is also true that the critical exponents calculated near the critical points possess identical values as mean field theory. Finally, we conclude that these findings shall provide some deep insights into the intriguing thermodynamic properties of the dyonic Ad S BHs with quasitopological electromagnetism in EGB gravity. 展开更多
关键词 AdS black hole phase transition triple point
下载PDF
Petrophysical Evaluation of Cape Three Points Reservoirs
5
作者 Striggner Bedu-Addo Sylvester Kojo Danuor Larry Pax Chegbeleh 《International Journal of Geosciences》 CAS 2024年第2期162-179,共18页
The findings of a study to ascertain and assess the petrophysical characteristics of Cape Three Points reservoirs in the Western basin with a view to describe the reservoir quantitatively using Well Logs, Petrel and T... The findings of a study to ascertain and assess the petrophysical characteristics of Cape Three Points reservoirs in the Western basin with a view to describe the reservoir quantitatively using Well Logs, Petrel and Techlog. The investigated characteristics, which were all deduced from geophysical wire-line logs, include lithology, porosity, permeability, fluid saturation, and net to gross thickness. To characterise the reservoir on the field, a suite of wire-line logs including gamma ray, resistivity, spontaneous potential, and density logs for three wells (WELL_1X, WELL_2X, and WELL_3X) from the Tano Cape Three Point basin were studied. The analyses that were done included lithology delineation, reservoir identification, and petrophysical parameter determination for the identified reservoirs. The tops and bases of the three wells analysed were marked at a depth of 1203.06 - 2015.64 m, 3863.03 - 4253.85 m and 2497.38 - 2560.32 m respectively. There were no hydrocarbons in the reservoirs from the studies. The petrophysical parameters computed for each reservoir provided porosities of 13%, 3% and 11% respectively. The water saturation also determined for these three wells (WELL_1X, WELL_2X and WELL_3X) were 94%, 95% and 89% respectively. These results together with the behaviour of the density and neutron logs suggested that these wells are wildcat wells. 展开更多
关键词 Petrophysical Cape Three points RESERVOIRS
下载PDF
Quantitative determination of the critical points of Mott metal–insulator transition in strongly correlated systems
6
作者 牛月坤 倪煜 +4 位作者 王建利 陈雷鸣 邢晔 宋筠 冯世平 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第1期647-652,共6页
Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transiti... Mottness is at the heart of the essential physics in a strongly correlated system as many novel quantum phenomena occur in the metallic phase near the Mott metal–insulator transition. We investigate the Mott transition in a Hubbard model by using the dynamical mean-field theory and introduce the local quantum state fidelity to depict the Mott metal–insulator transition. The local quantum state fidelity provides a convenient approach to determining the critical point of the Mott transition. Additionally, it presents a consistent description of the two distinct forms of the Mott transition points. 展开更多
关键词 critical point metal–insulator transition local quantum state fidelity strongly correlated system quasiparticle coherent weight
下载PDF
Analysis of the inflection points of height-diameter models
7
作者 Tzeng Yih Lam Mark J.Ducey 《Forest Ecosystems》 SCIE CSCD 2024年第4期414-422,共9页
The inflection point is an important feature of sigmoidal height-diameter(H-D)models.It is often cited as one of the properties favoring sigmoidal model forms.However,there are very few studies analyzing the inflectio... The inflection point is an important feature of sigmoidal height-diameter(H-D)models.It is often cited as one of the properties favoring sigmoidal model forms.However,there are very few studies analyzing the inflection points of H-D models.The goals of this study were to theoretically and empirically examine the behaviors of inflection points of six common H-D models with a regional dataset.The six models were the Wykoff(WYK),Schumacher(SCH),Curtis(CUR),HossfeldⅣ(HOS),von Bertalanffy-Richards(VBR),and Gompertz(GPZ)models.The models were first fitted in their base forms with tree species as random effects and were then expanded to include functional traits and spatial distribution.The distributions of the estimated inflection points were similar between the two-parameter models WYK,SCH,and CUR,but were different between the threeparameter models HOS,VBR,and GPZ.GPZ produced some of the largest inflection points.HOS and VBR produced concave H-D curves without inflection points for 12.7%and 39.7%of the tree species.Evergreen species or decreasing shade tolerance resulted in larger inflection points.The trends in the estimated inflection points of HOS and VBR were entirely opposite across the landscape.Furthermore,HOS could produce concave H-D curves for portions of the landscape.Based on the studied behaviors,the choice between two-parameter models may not matter.We recommend comparing seve ral three-parameter model forms for consistency in estimated inflection points before deciding on one.Believing sigmoidal models to have inflection points does not necessarily mean that they will produce fitted curves with one.Our study highlights the need to integrate analysis of inflection points into modeling H-D relationships. 展开更多
关键词 CONCAVITY Forest inventory and analysis Generalized height-diameter models Growth functions Height-diameter functions Mixed-effects modeling points of inflection Species-specific models
下载PDF
Analysis of the Significance of Key Points of Patient Interventional Psychological Care and Pain Care
8
作者 Xiaoping Dai Chu Luo Jiawei Dai 《Journal of Clinical and Nursing Research》 2024年第3期66-71,共6页
Interventional therapy has become increasingly popular in clinical practice due to advancements in medical technology.However,patients often experience psychological and physiological pressure due to its invasive natu... Interventional therapy has become increasingly popular in clinical practice due to advancements in medical technology.However,patients often experience psychological and physiological pressure due to its invasive nature.The management of patient discomfort and tension is crucial to ensure effective treatment.Psychological and pain management are essential components of interventional therapy,as they significantly impact patient recovery and prognosis.This article discussed the importance of interventional psychological and pain care for patients,starting with the development and spread of interventional therapy.The significance of providing high-quality nursing services to patients and improving their quality of life was also discussed. 展开更多
关键词 Interventional treatment Psychological nursing Pain care Key points Significance analysis
下载PDF
铀对α-Al_(2)O_(3)中氢与本征点缺陷相互作用的影响
9
作者 杨飞龙 向鑫 +2 位作者 胡立 张桂凯 陈长安 《原子与分子物理学报》 CAS 北大核心 2025年第5期123-129,共7页
在长期高温服役过程中,铀床的氚渗透泄露问题是聚变堆涉氚系统中需要关注的焦点之一,而一种行之有效的解决思路是在内壁制备阻氚涂层.然而,服役过程中通过热扩散渗入涂层内部的铀可能在阻氚涂层氢行为中起作用,进而影响其服役可靠性.基... 在长期高温服役过程中,铀床的氚渗透泄露问题是聚变堆涉氚系统中需要关注的焦点之一,而一种行之有效的解决思路是在内壁制备阻氚涂层.然而,服役过程中通过热扩散渗入涂层内部的铀可能在阻氚涂层氢行为中起作用,进而影响其服役可靠性.基于此,采用第一性原理计算方法,研究了铀对α-Al_(2)O_(3)中氢与本征点缺陷相互作用的影响.结果发现,铀对α-Al_(2)O_(3)中空位型本征点缺陷及氢相关缺陷的存在形式、电荷态及相对稳定性有重要影响.从形成能观点来看,铀对α-Al_(2)O_(3)中空位型本征点缺陷及氢相关缺陷的形成有利,且α-Al_(2)O_(3)中空位型点缺陷对氢的捕陷能力因铀的引入显著增加.研究结果对α-Al_(2)O_(3)基内壁阻氚涂层在氚工艺系统铀床中应用的可靠性评估具有重要的指导意义. 展开更多
关键词 本征点缺陷 氢相关缺陷 相互作用 α-Al_(2)O_(3)
下载PDF
滞动针干预“激痛点”对肌筋膜疼痛综合征模型大鼠中枢镇痛的作用机制
10
作者 赵丽萍 陈艺箔 +3 位作者 王雅倩 李之彤 张琪 苟波 《中国组织工程研究》 CAS 北大核心 2025年第17期3614-3623,共10页
背景:滞动针治疗肌筋膜疼痛综合征的镇痛效果显著,但镇痛机制尚不明确。目的:探索滞动针干预激痛点缓解肌筋膜疼痛综合征疼痛的作用机制。方法:按照随机数字表法将54只SD大鼠随机分为空白组(n=16)和造模组(n=38),造模组采用“打击结合... 背景:滞动针治疗肌筋膜疼痛综合征的镇痛效果显著,但镇痛机制尚不明确。目的:探索滞动针干预激痛点缓解肌筋膜疼痛综合征疼痛的作用机制。方法:按照随机数字表法将54只SD大鼠随机分为空白组(n=16)和造模组(n=38),造模组采用“打击结合离心运动”方式制备左侧股内侧肌筋膜疼痛综合征模型,造模12周后随机挑选6只验证造模成功,将剩余32只造模大鼠随机分为模型组(n=16)与滞动针组(n=16),使用滞动针对滞动针组大鼠左侧股内侧肌局部激痛点进行干预治疗,2次/周,治疗4周。造模前后及治疗后进行左足机械缩足阈值测定;治疗后第4周,苏木精-伊红染色观察大鼠左侧股内侧肌肌肉组织形态学变化,ELISA法检测血清和中脑导水管周围灰质中P物质、β-内啡肽水平,免疫组化检测中脑导水管周围灰质中小胶质细胞标志物(Iba-1)和c-fos阳性表达,Western Blot检测中脑导水管周围灰质脑源性神经营养因子蛋白表达。结果与结论:①与空白组比较,造模后模型组、滞动针组大鼠机械缩足阈值降低(P<0.05);治疗4周后,滞动针组大鼠机械缩足阈值高于模型组(P<0.05);②苏木精-伊红染色结果显示,模型组肌纤维排列紊乱、粗细不等,肌细胞增大并出现核内移现象,细胞内出现圆形挛缩结节以及紧张带;滞动针组肌纤维排列整齐,肌细胞多呈角状,细胞内偶见挛缩结节;③与空白组比较,模型组血清中P物质水平升高(P<0.05),血清中β-内啡肽及脑中P物质、β-内啡肽水平均降低(P<0.05);与模型组比较,滞动针组血清中P物质水平降低(P<0.05),血清中β-内啡肽及脑中P物质、β-内啡肽水平均升高(P<0.05);④与空白组比较,模型组c-fos、Iba-1阳性表达及脑源性神经营养因子蛋白均升高(P<0.05);与模型组比较,滞动针组c-fos阳性表达升高(P<0.05),Iba-1阳性表达及脑源性神经营养因子蛋白均降低(P<0.05);(5)结果表明,滞动针可能通过抑制中脑导水管周围灰质小胶质细胞的活性、下调脑源性神经营养因子蛋白表达间接促进小胶质细胞向M2表型极化释放β-内啡肽、增加c-fos神经元兴奋性,从而降低中枢致敏程度,有效缓解肌筋膜疼痛综合征疼痛的症状。 展开更多
关键词 肌筋膜疼痛综合征 激痛点 滞动针 中枢镇痛 脑源性神经营养因子 中脑导水管周围灰质
下载PDF
基于协同执行器的GCPS自适应调度模型 被引量:2
11
作者 张晶 陈垚 +1 位作者 孙俊 范洪博 《系统仿真学报》 CAS CSCD 北大核心 2019年第10期2112-2121,共10页
针对电网信息物理系统的不确定性易导致系统连锁故障的问题,建立基于协同执行器的GCPS自适应调度模型;分析了系统约束条件,提出了一种GCPS系统模型约束条件刻画电网系统的约束条件,并证明其度量与表示方法的一致性,通过PILOT求解逼近误... 针对电网信息物理系统的不确定性易导致系统连锁故障的问题,建立基于协同执行器的GCPS自适应调度模型;分析了系统约束条件,提出了一种GCPS系统模型约束条件刻画电网系统的约束条件,并证明其度量与表示方法的一致性,通过PILOT求解逼近误差最优值,描述了模型框架,通过PtolemeyII平台对模型的性能指标、输出功率准确度及故障对系统的影响进行仿真分析,实验结果表明模型可较为准确地描述电源输出功率,且系统对故障有较好的适应能力。 展开更多
关键词 电网信息物理系统 不确定性 实时性 自适应调度 约束条件
下载PDF
耳穴压豆联合磁刺激治疗产后压力性尿失禁临床观察
12
作者 何艳 唐慧 《中国中医药现代远程教育》 2025年第2期108-110,共3页
目的探究耳穴压豆联合磁刺激治疗产后压力性尿失禁的效果。方法选取潜江市中心医院2021年1月—2022年6月收治的产后压力性尿失禁患者60例作为研究对象,按照治疗方式的不同分为对照组、研究组,各30例。对照组予耳穴压豆治疗,研究组予耳... 目的探究耳穴压豆联合磁刺激治疗产后压力性尿失禁的效果。方法选取潜江市中心医院2021年1月—2022年6月收治的产后压力性尿失禁患者60例作为研究对象,按照治疗方式的不同分为对照组、研究组,各30例。对照组予耳穴压豆治疗,研究组予耳穴压豆联合磁刺激治疗。比较两组临床疗效及治疗后盆底肌力、60 min漏尿量、3 d漏尿次数、生活质量评分。结果研究组治疗总有效率为96.67%(29/30),高于对照组的80.00%(24/30)(P<0.05)。治疗后,研究组盆底肌肌力、生活质量评分均高于对照组,60 min漏尿量、3 d漏尿次数均低于对照组(P<0.05)。结论耳穴压豆联合磁刺激治疗产后压力性尿失禁的临床效果显著,不仅能够缓解盆底肌肌力、降低漏尿量及漏尿次数,还能促进产妇生活质量提高,缓解焦虑、降低压力,值得临床推广使用。 展开更多
关键词 产后压力性尿失禁 耳穴压豆疗法 磁刺激疗法
下载PDF
慢性肌筋膜触发点模型大鼠的尿液代谢组学分析
13
作者 刘琳 刘世轩 +1 位作者 陆馨悦 王侃 《中国组织工程研究》 CAS 北大核心 2025年第8期1585-1592,共8页
背景:慢性肌筋膜触发点通过非靶向代谢组学技术可识别差异性代谢物变化,有助于从内源性小分子代谢物层面理解并进一步探究慢性肌筋膜触发点的病理生理过程和发病机制。目的:以慢性肌筋膜触发点模型大鼠为研究对象,基于尿液代谢组学寻找... 背景:慢性肌筋膜触发点通过非靶向代谢组学技术可识别差异性代谢物变化,有助于从内源性小分子代谢物层面理解并进一步探究慢性肌筋膜触发点的病理生理过程和发病机制。目的:以慢性肌筋膜触发点模型大鼠为研究对象,基于尿液代谢组学寻找潜在生物标志物及相关代谢通路。方法:将16只SD大鼠随机分为造模组和正常组,造模组大鼠采用钝性打击结合离心运动(跑台坡度为-16°,跑速为16 m/min,训练时间为90 min/次)方式建立慢性肌筋膜触发点动物模型,每周1次,连续干预8周,休息4周;正常组大鼠不做干预。12周造模结束后,采用代谢笼法收集大鼠造模后24 h尿液,利用液相色谱-质谱联用非靶向代谢组学技术对尿样进行代谢图谱检测,筛选出共同差异代谢物,并进行生物信息学分析。结果与结论:①与正常组相比,造模组有32个差异代谢标志物,其中上调21个、下调11个;依据变量权重值>3,共14个差异代谢物被认定为潜在生物标志物;②京都基因与基因组百科全书富集分析表明,慢性肌筋膜触发点的形成与初级胆汁酸生物合成、花生四烯酸代谢通路密切相关。 展开更多
关键词 肌筋膜触发点 大鼠 尿液 代谢组学 生物信息学 生物标志物 差异代谢物 代谢笼法 运动损伤
下载PDF
CLINICAL STUDY ON THE TREATMENT OF POST-STROKE DEPRESSION WITH ELECTROACUPUNCTURE OF “NIWAN BAZHEN” POINTS 被引量:6
14
作者 蒋振亚 高李 +1 位作者 李常度 李金存 《World Journal of Acupuncture-Moxibustion》 2007年第1期11-16,共6页
Objective To observe the therapeutic effect of electroacupuncture (EA) of "Niwan Bazhen" points in the treatment of post-stroke depression. Methods A total of 66 post-stroke depression patients were randomized int... Objective To observe the therapeutic effect of electroacupuncture (EA) of "Niwan Bazhen" points in the treatment of post-stroke depression. Methods A total of 66 post-stroke depression patients were randomized into treatment group (EA+oral administration of Prozac-20, n =31 ) and control group (o- ral administration of Prozac-20, 20 mg/d, 28 days altogether, n =30). For patients of treatment group, EA (2/100 Hz, a tolerable stimulation strength) was applied to "Niwan Bazhen" points [Baihui (百会 GV20), etc. ] for 30 min, once daily, (except weekends) continuously for one month. Halmiton Rating Scale (HAMD) for Depression and Chinese Scale for Stroke (CSS) were used to evaluate the therapeutic effect. Results After the treatment, of the 30 and 31 cases in control and treatment groups, 4 and 6 were cured, 10 and 14 experienced marked improvement.in their symptoms, 6 and 7 had an improvement, 6 and 4 failed, with the cure+ markedly effective rates being 46.7% and 64.5% respectively. The therapeutic effect of treatment group was significantly superior to that of control group ( P〈0.05). The decreased values of both HAMD and C,,SS of treatment group were remarkably lower than those of control group (P〈0.01,0.05) . Conclusion EA of "Niwan Bazhen" points is an effective remedy for post-stroke depression. 展开更多
关键词 Post-stroke depression EA Niwon Bo.zhen points
下载PDF
Spatial variation law of vertical derivative zero points for potential field data 被引量:8
15
作者 王万银 张功成 梁建设 《Applied Geophysics》 SCIE CSCD 2010年第3期197-209,292,共14页
In this paper we deduce the analytic solutions of the first- and second-order vertical derivative zero points for gravity anomalies in simple regular models with single, double, and multiple edges and analyze their sp... In this paper we deduce the analytic solutions of the first- and second-order vertical derivative zero points for gravity anomalies in simple regular models with single, double, and multiple edges and analyze their spatial variation. For another simple regular models where it is difficult to obtain the analytic expression of the zero point, we try to use the profile zero points to analyze the spatial variation. The test results show that the spatial variation laws of both first- and second-order vertical derivative zero points are almost the same but the second-order derivative zero point position is closer to the top surface edge of the geological bodies than the first-order vertical derivative and has a relatively high resolution. Moreover, with an increase in buried depth, for a single boundary model, the vertical derivative zero point location tends to move from the top surface edge to the outside of the buried body but finally converges to a fixed value. For a double boundary model, the vertical derivative zero point location tends to migrate from the top surface edge to the outside of the buried body. For multiple boundary models, the vertical derivative zero point location converges from the top surface edge to the outside of the buried body where some zero points coincide and finally vanish. Finally, the effectiveness and reliability of the proposed method is verified using real field data. 展开更多
关键词 vertical derivative zero point spatial variation law edge location
下载PDF
钻孔联合地质剖面探测施工中若干问题探讨
16
作者 贺为民 《地球与行星物理论评(中英文)》 2025年第2期157-166,共10页
基于《活动断层探测》GB/T 36072—2018、《活动断层探查钻探》DB/T 92—2022等现行规范规程,对跨隐伏活动断层的钻孔联合地质剖面探测施工的基本要求和存在的主要问题进行了探讨,认为现行技术标准存在的问题有:(1)对岩芯采取率的要求偏... 基于《活动断层探测》GB/T 36072—2018、《活动断层探查钻探》DB/T 92—2022等现行规范规程,对跨隐伏活动断层的钻孔联合地质剖面探测施工的基本要求和存在的主要问题进行了探讨,认为现行技术标准存在的问题有:(1)对岩芯采取率的要求偏低;(2)对横跨隐伏逆断层的钻孔深度和钻孔之间距离的要求偏低.提出了下列改进措施:(1)各类岩土的岩芯采取率应大于现行技术标准要求的数值;其中,黏土的岩芯采取率应不小于99%;(2)对横跨隐伏逆断层的钻孔深度应大于现行技术标准要求的孔深;在第四系厚度较薄时,在逆断层上断点附近,位于逆断层上盘的钻孔在钻遇上盘的前第四系后,还应继续钻进,钻孔深度应达到能够揭露逆断层下盘的前第四系的深度;(3)当隐伏逆断层在第四系中的断距较小时,逆断层上断点两侧的2个相邻钻孔间距就需要1~3 m甚至更小的数值.补充了钻孔联合地质剖面探测中的钻孔布设方式、隐伏断层产状的求取方法.分析了在钻孔联合地质剖面探测的断层识别中存在的一些不确定性因素,并提出了相应对策.指出钻孔联合地质剖面探测施工是基于动态设计的信息化施工,现场技术负责人及其施工现场技术管理在钻孔联合地质剖面探测工作中起着重要作用. 展开更多
关键词 活动断层 钻孔联合地质剖面 断层活动性鉴定 断层上断点 岩芯采取率
下载PDF
RS+GCPs获取滑坡基本信息 被引量:8
17
作者 王治华 《中国地质灾害与防治学报》 CSCD 2004年第1期94-101,共8页
在20多年滑坡遥感调查实践的基础上,文章介绍RS+GCPs获取滑坡基本信息的信息源、滑坡基本信息、遥感图像地面分辨率与最小可识别滑坡及不同比例尺滑坡遥感调查的关系。遥感图像是获取滑坡及其发育环境信息的最基本和最重要的信息源。目... 在20多年滑坡遥感调查实践的基础上,文章介绍RS+GCPs获取滑坡基本信息的信息源、滑坡基本信息、遥感图像地面分辨率与最小可识别滑坡及不同比例尺滑坡遥感调查的关系。遥感图像是获取滑坡及其发育环境信息的最基本和最重要的信息源。目前用于滑坡调查的遥感数据可分为全色(panchromatic)、多光谱(Multi spectral)和雷达(SAR)3类。据传感器又分为航摄和卫星两大类。获取地面控制点 GCPs信息源的方法主要有地形图采集GCPs、GPS现场实测GCPs以及用航片立体像对、卫星图像像对或雷达数据产生DEM。经过合格几何校正和地理位置配准的正射影像,才能作为获取数字滑坡基本信息的基础。滑坡基本信息就是滑坡要素及滑坡发育环境要素。一个发育完全的滑坡,一般具有下列要素:滑坡体、滑坡周界、滑坡壁、滑坡台阶、滑坡舌、滑坡轴、滑坡鼓丘、拉张裂缝、剪切裂缝、扇形裂缝、鼓张裂缝、破裂缘、后缘洼地、滑动面、滑动带、滑坡床等。就滑坡解译而言,滑坡体和滑坡后壁两项为必要的最基本要素。产生滑坡的基本地质环境要素有:①能产生滑动面的物质(地层、岩体、堆积),②使部分斜坡与山体分离的软弱结构面或带,③使与山体分离的部分斜坡可能向前运动的临空面。滑坡遥感调查还需收集及调查包括人类活动状况在内的触发因素? 展开更多
关键词 滑坡 遥感监测 数据源 遥感图像 地面分辨率
下载PDF
Singular Points, Closed Orbits, Stable Manifolds and Unstable Manifolds of Second Order Autonomous Birkhoff Systems 被引量:1
18
作者 陈向炜 梅凤翔 《Journal of Beijing Institute of Technology》 EI CAS 1998年第4期330-336,共7页
Aim To study singular points, closed orbits, stable manifolds and unstable manifolds of a second order autonomous Birkhoff system. Methods Qualitative methods of ordinary differential equation were used. Results and ... Aim To study singular points, closed orbits, stable manifolds and unstable manifolds of a second order autonomous Birkhoff system. Methods Qualitative methods of ordinary differential equation were used. Results and Conclusion The criteria for singular points, closed orbits and hyperbolic equilibrium points of a second order autonomous Birkhoff system are given. Moreover the stability of equilibria, stable manifolds and unstable manifolds are obtained. 展开更多
关键词 Birkhoff system singular point closed orbit stable manifold unstable manifold
下载PDF
The Order of Approximation by Complex Rational Type Interpolating Operators at Fejer's Points 被引量:1
19
作者 王子玉 朱长青 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第3期66-70,共5页
In this paper, supose Γ be a boundary of a Jordan domain D and Γ satisfied Альпер condition, the order that rational type interpolating operators at Fejer's points of f(z)∈C(Γ) converge to f(z) in the se... In this paper, supose Γ be a boundary of a Jordan domain D and Γ satisfied Альпер condition, the order that rational type interpolating operators at Fejer's points of f(z)∈C(Γ) converge to f(z) in the sense of uniformly convergence is obtained. 展开更多
关键词 rational type interpolation Fejer's points order of approximation Jordan domain
下载PDF
The Order of Approximation by(0,1,…,q) Hermite-Fejer Interpolation Polynomials at Nearly Fejer's Points
20
作者 沈燮昌 王鸿飞 朱长青 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第1期81-88,共8页
Suppose that the outer mapping function of domain D has its second continuous derivatives. In this paper, the order proximation by (0,1,…,q) Hermite-Fejer interpolating polynomials at nearly Fejer's points of fun... Suppose that the outer mapping function of domain D has its second continuous derivatives. In this paper, the order proximation by (0,1,…,q) Hermite-Fejer interpolating polynomials at nearly Fejer's points of function of class A(D) are presented. Moreover in general the order of approximation is sharp. 展开更多
关键词 Hermite-Fejer interpolating Fejer's point
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部