mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
Wideband switchable dual-functional terahertz polarization converter based on vanadium dioxide-assisted metasurface

The terahertz technology has attracted considerable attention because of its potential applications in various fields. However, the research of functional devices, including polarization converters, remains a major demand for practical applications. In this work, a reflective dual-functional terahertz metadevice is presented, which combines two different polarization conversions through using a switchable metasurface. Different functions can be achieved because of the insulatorto- metal transition of vanadium dioxide (VO2). At room temperature, the metadevice can be regarded as a linear-to-linear polarization convertor containing a gold circular split-ring resonator (CSRR), first polyimide (PI) spacer, continuous VO2 film, second PI spacer, and gold substrate. The converter possesses a polarization conversion ratio higher than 0.9 and a bandwidth ratio of 81% in a range from 0.912 THz to 2.146 THz. When the temperature is above the insulator-to-metal transition temperature (approximately 68 ℃) and VO2 becomes a metal, the metasurface transforms into a wideband linearto- circular polarization converter composed of the gold CSRR, first PI layer, and continuous VO2 film. The ellipticity is close to -1, while the axis ratio is lower than 3 dB in a range of 1.07 THz-1.67 THz. The metadevice also achieves a large angle tolerance and large manufacturing tolerance.
Enlightenment of the Mariana Fore-arc Sedimentary Basin Evolution to the Subduction Process

The Mariana subduction structure is a hot topic in ocean-ocean subduction zone research, and its subduction mechanism has attracted wide attention from experts and scholars in China and abroad. Based on the multi-channel seismic data of survey line MGL1204 in the Mariana fore-arc and DSDP ocean drilling data, this paper studies the development and evolution characteristics of the structure and strata in the Cenozoic Mariana fore-arc sedimentary basin. The Cenozoic strata are divided into six seismic sequences, with the possible era of each seismic sequence discerned, and the relationship between fault development and earthquakes analyzed. The episodic activity of the volcanic chain of the Mariana island arc is thought to control the tectonic and stratigraphic development pattern of the Cenozoic sedimentary basin in the fore-arc. Between 16°N–19°N and 146°E–151°E, the maximum thickness of the sedimentary center of the Cenozoic fore-arc sedimentary basin in Mariana is about 2360 m. Normal faults are developed in the area and some broke to the seabed, indicating that the Mariana island arc is still in the post-arc expansion stage. The application of multi-channel seismic sections in structural and stratigraphic evolution study is an important means to elucidating the Mariana subduction mechanism.
Distributed state estimation for heterogeneous mobile sensor networks with stochastic observation loss

The problem of distributed fusion and random observation loss for mobile sensor networks is investigated herein. In view of the fact that the measured values, sampling frequency and noise of various sensors are different, the observation model of a heterogeneous network is constructed. A binary random variable is introduced to describe the drop of observation component and the topology switching problem caused by complete observation loss is also considered. A cubature information filtering algorithm is adopted to design local filters for each observer to suppress the negative effects of measurement noise. To derive a consistent and accurate estimation result, a novel weighted average consensus-based filtering approach is put forward. For the sensor that suffers from observation loss, its local prediction information vector is fused with the information contribution vectors of the neighbors to obtain the local estimation. Then the consensus weight matrix is designed for consensus-based distributed collaborative information fusion. The boundness of the estimation errors is proved by employing the stochastic stability theory. In the end, two numerical examples are offered to assert the validity of the presented method.
An Isentropic Mass Circulation View on the Extreme Cold Events in the 2020/21 Winter

Three extreme cold events successively occurred across East Asia and North America in the 2020/21 winter. This study investigates the underlying mechanisms of these record-breaking persistent cold events from the isentropic mass circulation (IMC) perspective. Results show that the midlatitude cold surface temperature anomalies always co-occurred with the high-latitude warm anomalies, and this was closely related to the strengthening of the low-level equatorward cold air branch of the IMC, particularly along the climatological cold air routes over East Asia and North America. Specifically, the two cold surges over East Asia in early winter were results of intensification of cold air transport there, influenced by the Arctic sea ice loss in autumn. The weakened cold air transport over North America associated with warmer northeastern Pacific sea surface temperatures (SSTs) explained the concurrent anomalous warmth there. This enhanced a wavenumber-1 pattern and upward wave propagation, inducing a simultaneous and long-lasting stronger poleward warm air branch (WB) of the IMC in the stratosphere and hence a displacement-type Stratospheric Sudden Warming (SSW) event on 4 January. The WB-induced increase in the air mass transported into the polar stratosphere was followed by intensification of the equatorward cold branch, hence promoting the occurrence of two extreme cold events respectively over East Asia in the beginning of January and over North America in February. Results do not yield a robust direct linkage from La Nina to the SSW event, IMC changes, and cold events, though the extratropical warm SSTs are found to contribute to the February cold surge in North America.
Impact of Joule heating and multiple slips on a Maxwell nanofluid flow past a slendering surface

This manuscript presents a study of three-dimensional magnetohydrodynamic Maxwell nanofluid flow across a slendering stretched surface with Joule heating. The impact of binary chemical reactions, heat generation, thermal radiation, and thermophoretic effect is also taken into consideration. The multiple slip boundary conditions are utilized at the boundary of the surface. The appropriate similarity variable is used to transfer the flow modeled equations into ODEs, which are numerically solved by the utilization of the MATLAB bvp4c algorithm. The involved parameter's impact on the concentration, velocity, and temperature distribution are scrutinized with graphs. The transport rates (mass, heat) are also investigated using the same variables, with the results reported in tabulated form. It is seen that the fluid relaxation, magnetic, and wall thickness characteristics diminish the velocities of fluid. Further, the velocity, concentration, and temperature slip parameters reduce the velocities of fluid, temperature, and concentration distribution. The results are compared to existing studies and shown to be in dependable agreement.
A new approach for determining GND and SSD densities based on indentation size effect: An application to additive-manufactured Hastelloy X

Dislocation plays a crucial role in controlling the strength and plasticity of bulk materials. However, determining the densities of geometrically necessary dislocations (GNDs) and statistically stored dislocations (SSDs) is one of the classical problems in material research for several decades. Here, we proposed a new approach based on indentation size effect (ISE) and strengthening theories. This approach was performed on a laser powder bed fused (L-PBF) Hastelloy X (HX), and the results were verified by the Hough-based EBSD and modified Williamson–Hall (m-WH) methods. Furthermore, to better understand the new approach and essential mechanisms, an in-depth investigation of the microstructure was conducted. The distribution of dislocations shows a clear grain orientation-dependent: low density in large<101> preferentially orientated grains while high density in fine <001> orientated grains. The increment of strengthening in L-PBF HX is attributed to a huge amount of edge-GNDs. Planar slip is the main operative deformation mechanism during indentation tests, and the slip step patterns depend mostly on grain orientations and stacking fault energy. This study provides quantitative results of GND and SSD density for L-PBF HX, which constructs a firm basis for future quantitative work on other metals with different crystal structures.
Nano-scale coating wear measurement by introducing Raman-sensing underlayer

For gaining fundamental insight into coating wear mechanisms and increasing operational efficiency and automation degree of equipment in important application fields of coating techniques, it is of great importance to developing novel wear measurement techniques enabling nanoscale studies of coating wear in the running process, but this remains a significant challenge. Here, a facile strategy is reported to achieve accurate coating thickness quantification at nanoscale level, which is based on a bilayer structure: a top target layer of a-C:H (hydrogenated amorphous carbon) film is considered as a light attenuating and anti-wear layer while underlayer of silicon serves as Raman-sensing layer. Through constructing the relationship between the thickness of a-C:H and Raman intensity of attenuated silicon signal, the coating thickness quantification method is established and successfully applied to quantify coating wear in the friction process. This approach can effectively avoid remarkable errors caused by tribo-induced effects in the interface regions, demonstrating its advantage in error tolerance. Details about these tribo-induced effects are also elucidated by a combination of Raman spectroscopy, optical profilometer, EELS, and TEM. In particular, the proposed approach enables the possibility of measuring coating wear with oil film on top, which breaks an important limitation of existed wear measurement methods, i.e., incapable of applying in oil-lubricated conditions. This approach can be used to quantify the wear condition of diverse target coatings and has the potential of online wear monitoring when combining a compact laser excitation and detection system.
Wave effects on the anti-liquefaction of the seabed around composite bucket foundation of offshore wind turbines

By using the open-source software OpenFOAM and the grid generation tool the integrated computer engineering and manufacturing code for computational fluid dynamics (ICEM CFD),a computational fluid dynamics-computational structural dynamics (CFD-CSD) coupling model is established.The dynamic response and the liquefaction of the seabed around the composite bucket foundation of the offshore wind turbines in the Xiangshui area of Jiangsu Province are investigated.The pore water pressure,the effective stress,the liquefaction depth and the anti-liquefaction effect of the overlying stones are analyzed.It is shown that the seabed around the composite bucket foundation will be liquefied under 50 year return waves,the liquefaction width is approximately 1/3 of the wavelength,and the maximum liquefaction depth is approximately 1/4 of the wave height.In addition,the overlying stones provide an effective anti-liquefaction method.Thicker,less porous overlying stones have a better anti-liquefaction effect.
Structural and Bonding Properties of Al_nC_4~(-/0) (n=2-4) Clusters: Anion Photoelectron Spectroscopy and Theoretical Calculations

We measured the photoelectron spectra of Al_nC_4~-(n=2-4) clusters by using size-selected anion photoelectron spectroscopy. The structures of Al_nC_4~-=0 (n=2-4) clusters were explored with quantum chemistry calculations and were determined by comparing the theoretical results with the experimental spectra. It is found that the most stable structure of Al_2C_4~-anion is a C_(2v) symmetry planar structure with two Al atoms interacting with two C_2 units. In addition, Al_2C_4~-anion also has a D_(∞h) symmetry linear structure with two Al atoms located at the two ends of a C_4 chain, which is slightly higher in energy than the planar structure. The most stable structure of neutral Al_2C_4 has a D_(∞h) symmetry linear structure. The most stable structure of Al_3C_4-anion is a planar structure with three Al atoms interacting with two C_2 units. Whereas neutral Al_3C_4 cluster has a C_(2v) symmetric V-shaped bent structure. The global minima structures of both Al_4C_4~-and neutral Al_4C_4 are C_2h symmetry planar structures with four Al atoms interacting with the ends of two C_2 units. Adaptive natural density partitioning analyses of Al_nC_4~-(n=2-4) clusters show that the interactions between the Al atoms and C_2 units have both σ and π characters.
Application of the generalized body-fixed coordinate system for the wave-body interaction problem of a small-depth elastic structure in head seas

The body-fixed coordinate system is applied to the wave-body interaction problem of a small-depth elastic structure which has both rigid and elastic body motions in head waves.In the weakly non-linear assumption,the perturbation scheme is used and the expansion is conducted up to second-order to consider several non-linear quantities.To solve the boundary value problem,linearization is carried out based not on inertial coordinate but on body-fixed coordinate which could be accelerated by a motion of a body.At first,the main feature of the application of body-fixed coordinate system for a seakeeping problem is briefly described.After that the transformation of a coordinate system is extended to consider an elastic body motion and several physical variables are re-described in the generalized mode.It has been found that the deformation gradient could be used for the transformation of a coordinate system if several conditions are satisfied.Provided there are only vertical bending in elastic modes and the structure has relatively small depth,these conditions are generally satisfied.To calculate an elastic motion of a body,the generalized mode method is adopted and the mode shape is obtained by solving eigen-value problem of dynamic beam equation.In the boundary condition of the body-fixed coordinate system,the motion effect reflected to free-surface boundary is considered by extrapolating each mode shape to the horizontal direction from a body.At last,simple numerical tests are implemented as a validation process.The second-order hydrodynamic force of a freely floating hemisphere is first calculated in zero forward speed condition.Next,motion and added resistance of a ship with forward speed are considered at different flexibility to confirm the effect of an elastic body motion in body-fixed coordinate system.
我国慢性阻塞性肺疾病早期防控的现状、挑战与思考

慢性阻塞性肺疾病(慢阻肺)是我国居民主要的死亡原因之一,加强慢阻肺早期防控有利于降低疾病负担,以较低成本取得较高健康绩效。我国存在慢阻肺知晓率低、肺功能检查率低、漏诊率高等状况。国家出台了《健康中国行动(2019-2030年)》等一系列文件及政策,大大推动了我国慢阻肺早期防控工作,但仍面临基层人力资源问题、肺功能筛查的质量问题、常态化疫情防控的影响等挑战。需持续从人员培训、人员配备、技术指引、经费支持等方面强化基层医疗机构对慢阻肺的筛查干预能力,调动各级医疗机构的积极性,整合各类医疗资源及社会力量,探索新的诊治技术,建立临床诊疗质控体系等,多途径、多层面推进慢阻肺早诊早治。
我国免费艾滋病抗病毒治疗启动与发展--走出一条中国特色抗病毒治疗道路

2001年,历史车轮刚刚驶入21世纪,建设中国特色社会主义事业进入了崭新的发展阶段。然而,艾滋病性病在我国流行却呈快速增长趋势,已成为党和政府高度重视的公共卫生问题。艾滋病发病人数快速上升,各类传播途径尚未阻断,尤其中原地区因20世纪90年代中期参与不规范采供血活动感染艾滋病病毒的农民进入发病高峰,到2002年,局部地区感染者集中发病、死亡增多。艾滋病病毒感染者大多为青壮年,发病死亡后,留下儿童、老人无人照顾,带来了严重的社会问题、沉重的经济和社会负担,引起了群众的极大恐慌,对当地的社会稳定造成了严重影响。艾滋病的医疗救治已刻不容缓。
基于改进RRT算法的7-DOF机械臂运动规划

针对七自由度的机械臂运动规划问题,提出了一种基于改进快速扩展随机树算法的新算法,Gm-RRT算法。新算法是在机械臂的关节空间内进行路径规划处理。新算法在高维空间中利用生成随机点数组而非单个随机点的方法提高了路径规划中的计算效率;引入自适应的目标虚拟引力的方法,保证了新算法在目标导向和向周围空间进行探索的平衡;利用弹性带原理和B样条曲线对机器人路径进行局部的优化和拟合。在最后基于MATLAB平台进行了仿真实验,实现了对冗余机械臂进行的运动规划。结果表明,改进算法能够较好地完成机械臂路径规划,同时保持了RRT算法的简洁特性。
隔膜分切机放卷张力混合串级控制系统设计

重绕分切是隔膜材料应用中的一个重要的工艺过程。为提高产品的质量和生产效率,以锂电池隔膜分切机中的放卷张力控制为研究对象,提出一种混合串级控制方案。考虑到张力滞后于速度,张力外环利用模型预测控制的优点,通过滚动优化,得到速度内环的给定值;速度内环通过反演控制律实现速度的自动跟踪,以达到稳定张力的目的。建立了张力及多轴驱动的动力学模型,基于模型设计了放卷张力的两级控制器;针对系统的扰动及建模不准等因素,设计了实时的干扰观测器对控制器进行补偿。仿真结果表明,提出的混合串级控制系统能够很好地适应隔膜分切机不同工况下的控制要求,具有很好的有效性和可靠性。在实际生产和相关控制研究中有一定借鉴意义。
履带式被动自适应机器人的通过性研究

危险灾害现场是非结构化地形环境,机器人辅助救援人员快速进入灾害现场,展开救援工作。要求机器人能够自适应于地形环境,具有良好的通过性能,对现场环境进行信息采集,对履带式被动自适应机器人建立多体动力学模型,利用RecurDyn软件建立整体机器人的几何模型,确定仿真参数为速度大小和地面参数;创建坡地、台阶和壕沟的地形模型,根据仿真参数分别对典型障碍物进行定量分析,选择机器人良好的通过性能。加工零件、组装样机,完成了履带式被动自适应机器人的样机,对坡地、台阶、壕沟和野外进行越障试验,观察越障过程,测量越障数据与仿真实验数据结果进行对比,确定机器人的通过性能并验证机械结构和参数设计的合理性。
基于最小二乘曲线拟合提取基频分量

输电线路发生单相接地故障,故障电流会产生直流偏移现象。针对故障信号提取基频分量时出现对直流偏移分量抑制能力较差、数学模型复杂和运算量较大的缺点,提出了一种新的基频分量提取算法。首先,使用均方根域-小波方法检测与定位故障发生时间,获取完整的故障时间段数据。然后,利用新构建的故障信号数学模型,将故障信号分解为基频分量和直流偏移分量。最后,对不同情况的故障信号提取基频分量并使用阻抗法计算故障发生位置,验证了算法的可行性和有效性。实验结果表明,算法对直流偏移分量具有良好的抑制能力,能快速准确地提取基频分量。
核电设备数字化设计平台关键技术研究与应用

核电设备结构复杂、设计周期长、涉及学科众多,传统的设计方式仍然停留在工具应用层面,设计过程缺乏规范化和协同化管理,设计数据散落在个人电脑上,难以共享和重用,数据孤立存在,缺少关联,价值难以挖掘。针对以上问题,利用互联网信息化技术,借鉴数据生命周期管理理念,结合核电设备设计特点,本文提出了核电设备数字化设计方法,基于该理论体系研发出核电设备设计平台。该平台实现了设计流程与任务规范化管理以及基于流程与数据的协同设计,封装了核电设备研发工具和方法,构建了一体化集成设计环境。目前,该平台已在中广核设计院的核电设备设计相关工作中广泛应用,得到了设计人员和管理人员等用户的认可,有效地推进了设计工作的标准化、自动化及智能化水平,具有很好地实际应用和推广价值。
时机理论干预在鞘内给药镇痛病人管理中的临床研究

疼痛是一种与实际或潜在的组织损伤相关的不愉快的感觉和情绪情感体验,或与此相似的经历,疼痛病人遭受生理侵害的同时,也面临着焦虑、抑郁情绪等心理痛苦及社交退缩及机体失能。 1986年WHO推出3阶梯镇痛后此模式在全球范围内逐渐普及,但该模式仍存在不良反应大、药物耐受等问题,尤其对于难治性癌痛及顽固性疼痛效果不佳,而《难治性癌痛专家共识(2017)》指出,癌症病人爆发痛高达33%~95%,10%~20%癌痛病人为难治性癌痛,因此近年来介入镇痛成为发展的新趋势。鞘内镇痛是指利用鞘内输注系统(intrathecal drug delivery systems, IDDS)将药物泵入蛛网膜下腔,通过脑脊液循环对大脑及脊髓产生直接镇痛作用,该方法镇痛作用确切且起效快,不良反应较少,临床主要应用于治疗难治性癌痛及顽固性疼痛。带泵病人的管理、健康教育及随访会影响其镇痛效果及生活质量。目前选择鞘内镇痛的病人数量不断增加,但相关的干预性研究较少,因此需要进一步探究不同干预方式对鞘内镇痛病人的应用效果。时机理论(timing it right, TIR)由Cameron于2008年提出,将疾病发展分为诊断期、稳定期、准备期、调整期及适应期,医护人员根据不同阶段病人治疗与护理的需求,给予针对性的专业知识、健康教育及情感支持,促使其身心及社会功能恢复。目前该理论在酒精依赖及慢性心力衰竭等群体中应用并取得较好效果,其干预机制符合鞘内镇痛病人照护需求但尚未在该人群中应用。为提高带泵病人生活质量,促进其身心及社会功能恢复,本研究基于时机理论对带泵镇痛病人展开干预,现报道如下。
全球清洁能源研究现状

基于爱思唯尔Scopus数据库,本文索引了2001- 2020年间发表的160多万篇研究文献及80多万项有效专利,梳理了全球清洁能源研究现状,希望能够为清洁能源未来研究指明方向,并为气候变化议题的探讨、政策及行动制定提供数据支持。
地理学视角下非物质文化遗产的跨地方实践

非物质文化遗产不仅是来源于过去的特定区域的传统实践,更是生成于全球化体系中面向未来的现代文化政治和文化经济过程。因此,本文尝试以跨地方性理论为切入点,架构非遗的形成、运作和认同的社会—空间过程,在此基础上使用跨地方聚合的思想重新概念化非遗实践,将其解读为多元主体权力关系中介下,由跨地方异质性要素聚合而成的不稳定的开放系统,以区别于固有对非遗实践“稳定”“以人为中心”和“边界化”的认知。通过分析云南鹤庆银器锻制技艺和摩梭纺织技艺两个案例来呈现非遗实践作为跨地方聚合的过程及特性,以及非遗传承和保护由此所面对的机遇和挑战,呼吁在重视非遗服务于乡村振兴等发展战略的潜力时,要进一步认识非遗实践的跨地方性对本土社区的影响,反思遗产原真性和文化价值与当前非遗实践的关系,强调在非遗全球化生产和消费中保持其与本土认同和本土生计之间的关联。
DNA damage repair promotion in colonic epithelial cells by andrographolide downregulated cGAS–STING pathway activation and contributed to the relief of CPT-11-induced intestinal mucositis

Gastrointestinal mucositis is one of the most debilitating side effects of the chemotherapeutic agent irinotecan (CPT-11). Andrographolide, a natural bicyclic diterpenoid lactone, has been reported to possess anti-colitis activity. In this study, andrographolide treatment was found to significantly relieve CPT-11-induced colitis in tumor-bearing mice without decreasing the tumor suppression effect of CPT-11. CPT-11 causes DNA damage and the release of double-stranded DNA (dsDNA) from the intestine, leading to cyclic-GMP-AMP synthase (cGAS)–stimulator of interferon genes (STING)-mediated colitis, which was significantly decreased by andrographolide both in vivo and in vitro. Mechanistic studies revealed that andrographolide could promote homologous recombination (HR) repair and downregulate dsDNA–cGAS–STING signaling and contribute to the improvement of CPT-11-induced gastrointestinal mucositis. These results suggest that andrographolide may be a novel agent to relieve gastrointestinal mucositis caused by CPT-11.
Recovery time of macroinvertebrate community from Cd pollution in Longjiang River,Guangxi,China

Estimating recovery times from pollution incident is an important issue of targeted biomonitoring programs.In the present study,the impact and recovery of macroinvertebrate communities from a cadmium wastewater discharge in the Longjiang River,Guangxi,China,in early January 2012 were studied based on 83 samples collected in five surveys within 20 months after the incident.The pollution affected seriously the local aquatic biota,and consequently,the invertebrate abundance and species richness were reduced considerably.Twelve months later,the taxonomic number of macroinvertebrates began to increase.However,sensitive taxa remained rare.Twenty months later,the taxon richness and abundance of macroinvertebrates increased significantly compared to those in the previous four time points.To explore the possible time-scale over which pre-disturbance conditions might occur,we chose four different typical metrics of taxa richness (total taxa number,cumulative taxa number,taxa number per samples,and the Shannon-Wiener diversity index) and extrapolated modeled recovery trajectories.Target values for the four metrics were set at average values for sites from the nearby Lijiang River,which were used as a reference.Assuming a continued linear trajectory,the recovery times were estimated to be 52,39,39,and 31 months,respectively,which was roughly 3-5 years.This is consistent with results from recovery times from other studies of acute pollution cases,but contrasted strongly to the much longer recovery times associated with chronic pollution from groundwater contamination and mine-tailing runoff.
TaMADS2-3D,a MADS transcription factor gene,regulates phosphate starvation responses in plants

Soil inorganic phosphate(Pi)levels are frequently suboptimal for the growth and development of crop plants.Although MADS-box genes participate in diverse plant developmental processes,their involvement in phosphate starvation responses(PSRs)remains unclear.We identified a type I MADS-box transcription factor gene,TaMADS2-3D,which was rapidly induced under low-Pi stress in roots of wheat(Triticum aestivum).A TaMADS2-3D-GFP fusion protein was found located in the nucleus.Transgenic Arabidopsis plants overexpressing TaMADS2-3D(TaMADS2-3DOE)showed shortened primary roots,increased lateral root density,and retarded seedling growth under high-Pi(HP)conditions,accompanied by increased Pi contents in their shoots and roots.The Arabidopsis TaMADS2-3DOE plants showed similar PSR phenotypes under low Pi(LP)conditions.These results indicate constitutive activation of PSRs by overexpression of TaMADS2-3D in Arabidopsis.Reactive oxygen species(ROS),H_2O_2 and O_2~-,levels were increased in root tips of Arabidopsis TaMADS2-3DOE plants under HP conditions.Transcriptome analysis of Arabidopsis TaMADS2-3DOE plants under different Pi regimes revealed expression changes for a variety of PSR genes including AtZAT6.Overexpression of TaMADS2-3D in wheat also led to constitutive activation of PSRs.We propose that TaMADS2-3D regulates plant PSRs probably by modulating ROS homeostasis,root development,PSR gene expression,and Pi uptake.This study increases our understanding of plant PSR regulation and provides a valuable gene for improving phosphorus-use efficiency in wheat and other crops.
Late Cretaceous K-rich rhyolitic crystal tuffs from the Chuduoqu area in Eastern Qiangtang subterrane: evidence for crustal thickening of the central Tibetan Plateau prior to India–Asia collision

In order to constrain whether the Lhasa–Qiangtang collision contributed to an early crustal thickening of the central Tibetan Plateau prior to the India–Asia collision, we present zircon LA–ICP–MS U–Pb ages, wholerock geochemistry, and zircon Hf isotopic compositions of the newly discovered rhyolitic crystal tuffs from the Chuduoqu area in the eastern Qiangtang subterrane, central Tibet. Zircon U–Pb dating suggests that the Chuduoqu rhyolitic crystal tuffs were emplaced at ca. 68 Ma. The Chuoduoqu rhyolitic crystal tuffs display high SiO_2 and K_2O, and low MgO, Cr, and Ni. Combined with their zircon Hf isotopic data, we suggest that they were derived from partial melting of the juvenile lower crust, and the magma underwent fractional crystallization and limited upper continental crustal assimilation during its evolution prior to eruption. They should be formed in a post-collisional environment related to lithospheric mantle delamination. The Chuduoqu rhyolitic crystal tuffs could provide important constraints on the Late Cretaceous crustal thickening of the central Tibetan Plateau caused by the Lhasa–Qiangtang collision.