mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
Fatigue Crack Initiation Potential from Defects in terms of Local Stress Analysis

The competition of surface and subsurface crack initiation induced failure is critical to understand very high cycle fatigue(VHCF) behavior, which necessitates the elucidation of the underlying mechanisms for the transition of crack initiation from surface to interior defects. Crack initiation potential in materials containing defects is investigated numerically by focusing on defect types, size, shape, location, and residual stress influences. Results show that the crack initiation potency is higher in case of serious property mismatching between matrix and defects, and higher strength materials are more sensitive to soft inclusions(elastic modulus lower than the matrix). The stress localization around inclusions are correlated to interior crack initiation mechanisms in the VHCF regime such as inclusion-matrix debonding at soft inclusions and inclusion-cracking for hard inclusions(elastic modulus higher than the matrix). It is easier to emanate cracks from the subsurface pores with the depth 0.7 times as large as their diameter. There exists an inclusion size independent region for crack incubation, outside which crack initiation will transfer from the subsurface soft inclusion to the interior larger one. As for elliptical inclusions, reducing the short-axis length can decrease the crack nucleation potential and promote the interior crack formation, whereas the long-axis length controls the site of peak stress concentration. The compressive residual stress at surface is helpful to shift crack initiation from surface to interior inclusions. Some relaxation of residual stress can not change the inherent crack initiation from interior inclusions in the VHCF regime. The work reveals the crack initiation potential and the transition among various defects under the influences of both intrinsic and extrinsic factors in the VHCF regime, and is helpful to understand the failure mechanism of materials containing defects under long-term cyclic loadings.
中国PX项目为何风波不断

2014年3月30日,广东省茂名市区群众在市政府门前大草坪聚集,表达对该市拟建芳烃(PX)项目的不满和抗议。3月31日凌晨,茂名市政府发布“告全体市民书”,呼吁公众通过和平、合法方式表达意见。与此同时,一场“PX词条争夺战”正在上演——由于PX在百度百科上的词条释义由“低毒化合物”被人修改为“剧毒化合物”,清华大学化工系学生将其修改回“低毒”后,近10人昼夜维护词条内容长达120小时。此后多天,国内主流媒体将目光聚焦于此。PX项目引发公众、媒体及科学界广泛热议。
Bilateral endogenous endophthalmitis secondary to group B streptococcal sepsis

To the editor: Endogenous bacterial endophthalmitis accounts for a small minority (2%-6%) of cases of endophthalmitis, but the visual outcome is almost always poor. ~1Group B streptococcus (GBS) accounts for only 5.2% among 267 endogenous endophthalmitis cases, and only about 30 cases have been reported in literature. We describe a rare case of bilateral GBS endogenous endophthalmitis and suggest that GBS should be a leading suspect in bilateral endogenous endophthalmitis.
Relevance of muscle biopsy for diagnosing multifocal motor neuropathy

Multifocal motor neuropathy (MMN) is a rare, focal, inflammatory, demyelinating disease of the peripheral nerves with pure motor involvement.~1 MMN is clinically characterized by slowly progressive, asymmetric, distal, upper limb predominant weakness, in the absence of sensory disturbances.~2 Weakness is usually multifocal and connected to a distinct motor nerve, such as the musculocutaneous nerve resulting in biceps weakness, the posterior interosseus nerve resulting in finger drop, the median, ulnar, or radial nerve resulting in dexterity problems or grip weakness, or the peroneal nerve resulting in a foot drop. Onset of clinical manifestations is between 20 and 50 years of age. The prevalence of MMN is reported as 1-2 per 100 000.~2 MMN is three times more frequent in men as compared to women. MMN follows a chronic or stepwise progressive course, affects the myelin sheath, has an immune-mediated pathogenesis, and presents with multifocal motor conduction blocks. MMN responds favorably to immunoglobulins (IVIG) in about 80% of the cases but not to steroids or plasmapheresis.~3 The diagnosis of MMN is usually established upon clinical presentation, nerve conduction studies revealing focal conduction block, elevated serum titers of anti-GM1 antibodies, and the favorable response to IVIG.~1 Occasionally, motor nerve biopsy is carried out in MMN to support the diagnosis of a focal or multifocal demyelination. Whether muscle biopsy plays a role in the diagnostic work-up of MMN is questionable.
Research progress in traumatic brain penumbra

Objective Following traumatic brain injury (TBI), brain tissue that surrounding the regional primary lesion is known as traumatic penumbra; this region may undergo secondary injury and is considered to have the potential to recover. This review aimed to reveal the existence and significance of traumatic penumbra by analyzing all relevant studies concerning basic pathologic changes and brain imaging after TBI. Data sources We collected all relevant studies about TBI and traumatic penumbra in Medline (1995 to June 2013) and ISI (1997 to March 2013), evaluated their quality and relevance, then extracted and synthesized the information. Study selection We included all relevant studies concerning TBI and traumatic penumbra (there was no limitation of research design and article language) and excluded the duplicated articles. Results The crucial pathological changes after TBI include cerebral blood flow change, cerebral edema, blood-brain barrier damage, cell apoptosis and necrosis. Besides, traditional imaging method cannot characterize the consequences of CBF reduction at an early stage and provides limited insights into the underlying pathophysiology. While advanced imaging technique, such as diffusion tensor imaging (DTI) and positron emission tomography (PET), may provide better characterization of such pathophysiology. Conclusions The future of traumatic brain lesions depends to a large extent on the evolution of the penumbra. Therefore, understanding the formation and pathophysiologic process of the traumatic penumbra and its imaging research progress is of great significant for early clinical determination and timely brain rescue.
Mitochondrial biogenesis of astrocytes is increased under experimental septic conditions

Background Mitochondrial dysfunction has been reported to be one of the contributing factors of sepsis-associated encephalopathy (SAE). Mitochondrial biogenesis controls mitochondrial homeostasis and responds to changes in cellular energy demand. In addition, it is enhanced or decreased due to mitochondrial dysfunction during SAE. The aim of this study was to explore the changes of mitochondrial biogenesis of astrocytes under septic conditions. Methods Lipopolysaccharide (LPS; 50 ng/ml) and interferon-y (IFN-y; 200 U/ml) were incubated with astrocytes to model the effects of a septic insult on astrocytes in vitro. The mitochondrial ultrastructure and volume density were evaluated by transmission electron microscopy. Intracellular adenosine triphosphate (ATP) levels were detected by the firefly luciferase system. The expression of protein markers of mitochondrial biogenesis and the binding ability of mitochondrial transcription factor A (TFAM) were determined by western blot and electrophoretic mobility shift assays, respectively. The mitochondrial DNA (mtDNA) content was detected by real-time polymerase chain reaction. Results The number of mildly damaged mitochondria was found to be significantly greater after treatment for 6 hours, as compared with at 0 hour (P<0.05). The mitochondrial volume density was significantly elevated at 24 hours, as compared with at 0 hour (P<0.05). The ATP levels at 6 hours, 12 hours, and 24 hours were significantly greater than those at 0 hour (P<0.05). The protein markers of mitochondrial biogenesis were significantly increased at 6 hours and 12 hours, as compared with at 0 hour (P<0.05). The TFAM binding activity was not significantly changed among the four time points analyzed. The mtDNA contents were significantly increased at 12 hours and 24 hours, as compared with at 0 hour (P<0.05). Conclusions Under septic conditions, mitochondrial biogenesis of astrocytes increased to meet the high-energy demand and to promote mitochondrial recovery. Furthermore, the TFAM-DNA binding ability was not sensitive to sepsis-induced injury.
针刺联合循经按摩、中药外敷为主治疗哺乳期急性乳腺炎25例

哺乳期急性乳腺炎的发病率有逐年升高的趋势,因要考虑到对哺乳和婴儿的影响,所以治疗上比较棘手。近年来,笔者运用针刺联合循经按摩、中药芒硝外敷等中医特色疗法治疗哺乳期急性乳腺炎,现报道如下。
Engineering cybernetics: 60 years in the making

The landmark book of Hsue-Shen Tsien, ‘Engineering Cybernetics’, gave birth 60 years ago to an engineering science of interrelations and synthetic behaviors. Clothing the bare bones of Norbert Wiener’s conception of cybernetics, the book delineates for the new science the requirement (of having direct impacts on engineering applications), the aim (of encapsulating engineering principles and concepts), the problems (of analysis, design, and uncertainty), the tools (of basic and advanced mathematics), and the scope (systems that are single input and output or multiple input and output, linear or nonlinear, deterministic or stochastic). The book is a showcase of originality, critical thinking and foresights. In particular, the author calls into question the basic assumption that ‘the properties and characteristics of the system to be controlled were always assumed to be known’ and points out that, in reality, ‘large unpredictable variations of the system properties may occur’. Sixty years later, the full spectrum of Tsien’s prophetic ideas is yet to be fully grasped and engineering cybernetics, as Tsien envisioned, is still in the making.
Reconstruction of 3D light distribution produced by cylindrical diffuser in deep tissues based on photoacoustic imaging

Measurement of light distribution in biological tissue contributes to selecting strategy and optimizing dose for biomedical application. In this letter, a photoacoustic method combined with Monte Carlo simulation was used to estimate the three-dimensional light distribution in biological tissue. The light distribution was produced by a cylindrical diffuser which interposed into tissues. The light profiles obtained by the method were compared to those detected by photo diodes. The experimental results demonstrate the feasibility of this method. The approach can play a significant role for photo-dosimetry in biomedical phototherapy.
Optical phase control for MMW sparse aperture upconversion imaging

The random phase errors of the optical carriers are discussed and controlled for passive millimeter-wave sparse aperture (PMMW SA) upconversion imaging. A two-channel model is set up for analyzing characteristics of the phase errors, and an active optical control technique based on stochastic parallel gradient decent algorithm (SPGD controller) is proposed to calibrate the phase errors. To demonstrate the feasibility of the SPGD controller, simulations are performed and an experimental system with a two-channel fiber array is set up. Simulation and experiment results show that the SPGD controller can effectively and rapidly compensate the phase errors of the optical carrier, and the accuracy of the phase control is sufficient for imaging systems.
A Method to Distinguish Twinning Variants and Second Twins by EBSD Measurements

This paper proposes a direct and simple method to identify the second twins from twinning variants by electron back scattered diffraction (EBSD). To clarify the orientation relationship between the neighboring crystals, the misorientation calculation by MATLAB software based on the EBSD data is also used. This method is generally applicable to predict the variants occurring in the nucleation and growth of the recrystallization or phase transformation process.
左心房黏液瘤超声表现1例

心脏黏液瘤并非罕见,约占心脏全部肿瘤的30%~50%,其中90%以上的黏液瘤发生于心房,左房黏液瘤发生率最高,约为右房黏液瘤的3~4倍。该例患者超声表现为左房内非均质团块占位,团块的结构、形态及附着部位似为附壁血栓,而真正血栓发生部位多位于左房后壁、外侧壁及左心耳处,因此不支持附壁血栓的诊断。结合临床分析,该患者1年来间断头晕、心慌、胸闷、憋气等症状逐渐加重,发作次数频繁增多,可能与瘤体增长迅速,瘤体增大,占据左房腔一定的容积,左房血充盈量减少,脑、心脏自身血容量灌注不足有关。患者术后3 d行彩色多普勒超声心动图检查:左房内径32 mm,左室内径测值46 mm,射血分数达71%。心电图心肌缺血现象明显好转。术后证实彩色多普勒超声诊断与病理诊断结果一致,彩色多普勒超声检查为临床提供了可靠的诊断依据。
应用传统文化陶冶实习护生人文情怀

目的探索护理教育过程中医德情怀陶冶、人文精神塑造。方法挖掘中国传统文化汲取医学人文精神,努力营造传统文化育人氛围,在实践技能成长过程中实施人文素质教育渗透。结果通过教改项目的实施,与往届实习护生相比,在仪容仪表、服务意识、操作水平、尊师守纪、沟通协作方面,带教老师满意度显著提高(均P<0.05),护理教学质量也有所提高。结论在护理教育中弘扬中国传统人文精神具有重大意义,“温、良、恭、俭、让”应成为护理人员高尚人文素质的集中体现。
Hedgehog signaling downregulates Suppressor of Fused through the HIB/SPOP-Crn axis in Drosophila

Hedgehog (Hh) signaling plays vital roles in animal development and tissue homeostasis, and its misregulation causes congenital diseases and several types of cancer. Suppressor of Fused (Su(fu)) is a conserved inhibitory component of the Hh signaling pathway, but how it is regulated remains poorly understood. Here we demonstrate that in Drosophila Hh signaling promotes downregulation of Su(fu) through its target protein HIB (Hh-induced BTB protein). Interestingly, although HIB-mediated downregulation of Su(fu) depends on the E3 ubiquitin ligase Cul3, HIB does not directly regulate Su(fu) protein stability. Through an RNAi-based candidate gene screen, we identify the spliceosome factor Crooked neck (Crn) as a regulator of Su(fu) level. Epistasis analysis indicates that HIB downregulates Su(fu) through Crn. Furthermore, we provide evidence that HIB retains Crn in the nucleus, leading to reduced Su(fu) protein level. Finally, we show that SPOP, the mammalian homologue of HIB, can substitute HIB to downregulate Su(fu) level in Drosophila. Our study suggests that Hh regulates both Ci and Su(fu) levels through its target HIB, thus uncovering a novel feedback mechanism that regulates Hh signal transduction. The dual function of HIB may provide a buffering mechanism to fine-tune Hh pathway activity.
色谱技术在天然活性物分离分析中的应用

1循环高效液相色谱技术分离纯化复杂生物源的复合糖当前,糖生物学领域亟须建立糖标准品库,尽管许多低聚糖已能通过化学合成方法获得,但一些具有重要生理活性的复合糖仍难以合成制备。为解决这一问题,美国印第安纳大学伯明顿分校的Novotny等采用循环高效液相色谱技术从多种天然产物中分离纯化复合糖。循环高效液相色谱由2根色谱短柱和1个十通阀组成,十通阀将待分离组分交替循环输入2根色谱柱进行循环分离,通过连续的循环操作方式实现模拟长柱的色谱分离效果,获得了比传统长色谱柱更高的分离效率。在此之前该方法尚未用于复杂生物活性物质的分离。他们应用此方法通过亲水性色谱柱Amide-80有效分离了海藻低聚糖混合物以及糖蛋白中N-聚糖混合物,并得到纯度>98%的低聚糖及聚糖同分异构体,如棉子糖和松三糖、3种高甘露糖型聚糖异构体。
Construction of lake bathymetry from MODIS satellite data and GIS from~2003 to 2011

In recent years, sedimentation conditions in Dongting Lake have varied greatly because of significant changes in runoff and sediment load in the Changjiang (Yangtze) River following the construction of Three Gorges Dam. The topography of the lake bottom has changed rapidly because of the intense exchange of water and sediment between the lake and the Changjiang River. However, time series information on lake-bottom topographic change is lacking. In this study, we introduced a method that combines remote sensing data and in situ water level data to extract a record of Dongting Lake bottom topography from~2003 to 2011. Multi-temporal lake land/water boundaries were extracted from MODIS images using the linear spectral mixture model method. The elevation of water/land boundary points were calculated using water level data and spatial interpolation techniques. Digital elevation models of Dongting Lake bottom topography in different periods were then constructed with the multiple heighted waterlines. The mean root-mean-square error of the linear spectral mixture model was 0.036, and the mean predicted error for elevation interpolation was -0.19 m. Compared with field measurement data and sediment load data, the method has proven to be most applicable. The results show that the topography of the bottom of Dongting Lake has exhibited uneven erosion and deposition in terms of time and space over the last nine years. Moreover, lake-bottom topography has undergone a slight erosion trend within this period, with 58.2% and 41.8% of the lake-bottom area being eroded and deposited, respectively.
Measurement of trace nitrate concentrations in seawater by ion chromatography with valve switching

An ion chromatographic method with a valve switching facility was developed to determine trace nitrate concentrations in seawater using two pumps, two different suppressors, and two columns. A carbohydrate membrane desalter was used to reduce the high concentrations of sodium salts in samples. In this method, trace nitrate was eluted from the concentrator column to the analytical columns, while the matrix flowed to waste. Neither chemical pre-treatment nor sample dilution was required. In the optimized separation conditions, the method showed good linearity (R >0.99) in the 0.05 and 50 mg/L concentration range, and satisfactory repeatability (RSD<5%, n =6). The limit of detection for nitrate was 0.02 mg/L. Results showed that the valve switching system was suitable and practical for the determination of trace nitrate in seawater.
Temporal and spatial variations in the distribution of macroalgal communities along the Yantai coast, China

To explore the impact of environmental variables on macroalgal communities, their temporal and spatial distributions were examined along the Yantai coast, China between April 2010 and March 2011. Macroalgae sampling was conducted monthly at four sites along the coast: Jiahe River estuary, Zhifu Island, Fisherman's Wharf, and Yangma Island. The species composition and abundance, and their relationship with environmental variables were assessed. Along the Yantai coast, 35 macroalgae species were identified, including 24 Rhodophyta spp., 7 Chlorophyta, and 4 Phaeophyta spp. Highest species numbers were recorded in the summer at all sampling sites, except in the Jiahe River estuary. Macroalgae biomass was the greatest in the summer. Year-round, the highest species number and dry biomass recorded at Fisherman's Wharf and Yangma Island was attributed to the substrate type. In summer, Ulva pertusa Kjellman was the dominant species identified along the Yantai coast, which indicates a risk of macroalgae blooms. Our results show that seawater temperature and nutrients appear to significantly affect the temporal and spatial patterns of macroalgal abundance along the Yantai coast. The effects of environmental variables on the macroalgae on the Yantai coast need further study.
TWO-LEVEL MULTISCALE FINITE ELEMENT METHODS FOR THE STEADY NAVIER-STOKES PROBLEM

In this article, on the basis of two-level discretizations and multiscale finite el- ement method, two kinds of finite element algorithms for steady Navier-Stokes problem are presented and discussed. The main technique is first to use a standard finite element dis- cretization on a coarse mesh to approximate low frequencies, then to apply the simple and Newton scheme to linearize discretizations on a fine grid. At this process, multiscale finite element method as a stabilized method deals with the lowest equal-order finite element pairs not satisfying the inf-sup condition. Under the uniqueness condition, error analyses for both algorithms are given. Numerical results are reported to demonstrate the effectiveness of the simple and Newton scheme.
黄河源区多年冻土活动层和季节冻土冻融过程时空特征

基于黄河源区2010~2012年4个监测场地的土壤温度和水分资料, 分析了多年冻土活动层和季节冻土冻融过程时空差异. 结果表明, 4个场地地温和冻土厚度不同, 活动层底板或最大季节冻结深度年平均温度(TTOP)分别为: 查拉坪场地(CLP) -1.9℃, 扎陵湖场地(ZLH)-0.9℃, 麻多乡场地(MDX) –0.4℃, 鄂陵湖场地(ELH)1.1℃. 冻融过程差异与冻土温度和TTOP 相关, 随着TTOP 升高, 融化开始时间提前, CLP 在6月初, ZLH 在5月中下旬, MDX在5月初, ELH 在4月上旬; 冻结开始时间滞后, CLP 为10月初, ZLH 为10月上中旬, MDX为10月中旬, ELH 为10月中下旬; 活动层整体冻结期随之减小, CLP 为202 d, ZLH 为130 d,MDX 为100 d, ELH 整体融化期为89 d. CLP 和ZLH 冻结融化过程均于年内完成, 冻结过程表现为由上向下和由下向上双向进行. MDX 冻结过程持续至次年1月末, 但在冻结期末冻结速率很小, 由下向上冻结因极微弱而呈单向进行. ELH 冻结持续至次年5月初, 出现季节冻结和季节融化过程并存格局; 冻结过程单向进行, 但融化呈现微弱的双向过程; 6月下旬至7月初双向融化比较稳定. 各场地随着TTOP升高, 由下向上冻结速率相对由上向下的减慢, 由下向上的冻结深度减小, 融化过程相对冻结过程持续时间比值减小. 总之, 黄河源区活动层季节冻融过程与青藏高原其他地区有比较显著的差异.
Decomposition of 2-Mercaptoethyl O-Ester: SN2 Displacement or Acyl Transfer? A Theoretical Study

The mechanism for the decomposition of 2-mercaptoethyl O-ester was theoretically investigated. The mechanism that 2-mercaptoethyl O-ester undergoes an SN_2 displacement of the O atom by the S atom on α-C is much favored over the mechanism of N-to-S acyl transfer. The length of the alcohol moiety has large effects on the decomposition efficiency of thiol-substituted alkyl O-esters. The reactivities of these esters are controlled by distortion energies. Only 2-mercaptoethyl O-ester can undergo the decomposition at room temperature due to the low distortion energy to achieve the transition state geometry. If the thiol group of 2-mercaptoethyl O-ester is replaced by an amino group, the N-to-N acyl transfer mechanism is more favored than the SN_2 displacement mechanism.
CMIP5多模式对全球典型干旱半干旱区气候变化的模拟与预估

应用CRU 3.1气温资料和GPCC V6降水数据, 系统评估了国际耦合模式比较计划第5阶段(CMIP5)中17个耦合模式对全球典型干旱半干旱区的长期气候变化的模拟能力, 并在此基础上分析了不同典型浓度路径(representative concentration pathways, RCPs)下典型干旱半干旱区未来的气候变化情景. 结果表明: 大多数模式都能模拟出全球陆地以及典型干旱半干旱区观测气温时空分布特征, 特别是近60年来显著增温的空间格局, 但增温幅度偏小0.1~0.3℃/50 a;大多数模式难以捕捉到全球陆地观测降水的年际变化特征, 模拟的变率和趋势均明显偏弱, 不同模式对干旱半干旱区降水的模拟存在较大的时空差异, 但总体上还是多模式集成结果更为接近观测值; 在人类活动和自然变化的共同影响下, 全球及其不同干旱半干旱区未来气温的变化均是以显著增温为主, 特别是高端浓度路径(RCP 8.5)下的增温幅度几乎是中低端浓度路径(RCP 4.5)下的2倍; 降水的未来变化情景基本上是“干愈干、湿愈湿”的时空特征, 也是高端浓度路径下的变化更为明显; 而未来中国北方干旱半干旱区很可能是气温上升、降水增加最为显著的地区之一.
数据填补及能量闭合对半干旱区生态系统年净碳交换的影响

基于半干旱区2种不同下垫面(草地和旱作农田)2005和2008年涡动相关法取得的通量资料, 分析了数据填补、能量收支闭合率以及摩擦风速(u~*)阈值等对生态系统年净碳交换的影响. 通过加入4种不同长度的人工空缺(空缺长度从0.5 h~12 d), 比较了平均日变化法(MDV)、边缘分布抽样法(MDS)和非线性回归法等6种填补方法的填补效果. 结果表明, MDS 的整体表现最好, 特别是对长空缺的填补效果优于其他方法, 估算的年NEE 偏差在5 g C m~(-2) a~(-1)以内. 非线性回归法估算的夜间NEE 具有较大的正偏差, 表明非线性回归法估算的夜间生态系统呼吸偏高. 4种非线性回归法估算的年NEE 偏差在8.0~30.8g C m~(-2) a~(-1). 由于在半干旱区土壤含水量是生态系统碳交换的重要限制因子, 非线性回归法中综合考虑土壤温度和土壤含水量影响的Non_linear3和Non_linear4表现较好. MDV对白天NEE 空缺的填补优于夜间, 估算的年NEE 偏差在?2.6~?13.4 g C m~(-2) a~(-1). 总体上, 数据填补的精确度受下垫面类型、空缺长度以及空缺出现时间(白天、晚上)影响. 2个观测站点的能量收支闭合率在80%左右. 能量收支闭合率受湍流强度影响显著; 当夜间摩擦风速较低时, 湍流混合不充分, 能量收支闭合率也较低. 生态系统在某个风向的累积通量印痕较大时, 有效能量和湍流通量源区的不匹配造成这一风向上的能量收支闭合率也较低. 通过假设能量收支不闭合全部由感热通量和潜热通量的低估引起, 评估了能量闭合订正对生态系统CO_2通量的影响. 结果表明经过订正后的草地、农田的年净碳交换量平均增加近10 g C m~(-2) a~(-1). 此外当u~*阈值从0.1增加到0.2 m s~(-1),年净碳交换平均增加37.5 g C m~(-2) a~(-1),这表明u~*阈值的设定对生态系统的年净碳交换影响较大.
念青唐古拉山西段冰碛垄漂砾~(10)Be暴露测年及末次冰期序列

气温和亚洲季风降水变化影响青藏高原冰川的进退, 念青唐古拉山西段末次冰期年代的研究能够为认识季风影响过渡带的冰期气候特征提供重要依据. 然而, 该地区末次冰期时代及其南北坡是否存在差异仍不确定. 本文采用~(10)Be 暴露测年方法, 对青藏高原南部的念青唐古拉山西段北坡的爬玉王山谷谷口两道冰碛垄的年代进行测定, 确认内侧冰碛垄为末次冰盛期产物,年代为(18.0±1.7)~(30.6±2.8) ka(n=10). 外侧冰碛垄时代为(18.0±1.6)~(39.9±3.7) ka(n=5), 可能对应MIS3阶段或更早的冰进. 与念青唐古拉山西段南坡~(10)Be 暴露年代对比表明, 念青唐古拉山西段末次冰期最大规模冰进可能发生在MIS3阶段, 与全球降温不同步, 具有异时性, 但在区域内则具有同时性, 可能响应北半球千年尺度气候变化.
中国主要土壤高光谱反射特性分类与有机质光谱预测模型

土壤可见-近红外漫反射光谱是当前对地遥感观察和土壤近地传感器研究的重要方向, 同时也被认为是土壤数字制图、精确农业和土壤资源调查等方面最重要的数据获取技术. 从中国西藏、新疆、黑龙江、海南等地采集16种土类的1581个土壤样本, 经干燥过筛后统一采用 ASD 光谱仪测量了其室内可见-近红外反射光谱(350~2500 nm). 对所有的土壤光谱数据采用Savitzky-Golay 平滑加一阶微分进行转换, 来减少大样本数据受到实验室光学测试环境条件差异的影响, 然后对数据进行主成分变换降维处理. 引入模糊k-means 方法进行大样本光谱数据的最佳分类数目计算, 并将中国土壤光谱数据分成五类, 各自代表了不同的土壤矿物和有机组分, 主要类型与国际同行类似成果有可比性. 最后提出了采用土壤光谱分类方法结合偏最小二乘回归法(PLSR)方法建立土壤有机质的光谱分类-局部预测模型, 结果比未分类直接采用PLSR 方法的一阶微分-全局预测模型的精度有了显著提高, 其预测模型的R~2和RPD两个指数分别从0.697和1.817提高到0.899和3.158.
利用地表变形直接推算地震断层破裂深度

地震断层几何形态的确定是研究断层震源破裂过程和地面运动的先决条件. 其中断层的破裂深度和倾角是两个未知的关键参数. 半无限空间的地震弹性位错理论公式表明, 除纯走滑断层以外, 对于断层破裂至地表的地震产生的地表变形, 其上盘水平应变的零值点与破裂深度之间存在简单的对应关系, 可由地表的零应变点直接推算断层深度. 本文通过数值计算方法探讨了盲断层与非均匀介质情形下, 利用地表零应变点推算断层破裂深度的可行性. 结果显示, 介质和应力场的非均匀性一定程度上影响了对应关系; 对于盲断层, 当埋深在~1 km 以内时, 对应关系近似成立. 此外, 根据地表水平变形还可估算断层倾角的范围. 最后探讨了如何根据大地震后的孔径雷达干涉方法记录推算断层破裂深度的方法, 并将此方法应用于2008年汶川大地震, 获得了这次地震的断层破裂深度. 这种利用地表变形观测确定断层几何参数的方法简便易行, 没有余震的影响, 可以为反演提供有价值的约束.
新疆西南天山科克苏河新发现榴辉岩岩石学特征和相平衡研究及其地质意义

西南天山高压-超高压变质带东段特克斯县科克苏河一带首次发现了榴辉岩和含绿辉石的蓝片岩, 通过详细的岩石学研究, 并运用THERMOCALC 软件、在MnNC(K)FMASHO体系下对其进行了相平衡模拟. 选择的样品为新鲜的榴辉岩TK003, 含绿辉石包体的蓝片岩TK026-8及退变榴辉岩TK027. 3个样品石榴石成分均显示出从核部到边部X_(py)和X_(grs)逐渐升高, X_(sps)不断降低的变质生长环带特征. 相平衡模拟结果显示, 榴辉岩和蓝片岩经历了相似的P-T 演化轨迹, 早期近等压条件下升温至峰期, 达到榴辉岩相变质作用温压范围, 峰期温压条件为T=480~515℃, P=2.0~2.3 GPa; 而后在近等温条件下快速降压, 退变初期经历的温压条件为515~519℃, 1.78~1.93 GPa. 不同样品中变质矿物组合及其含量的不同主要受全岩成分控制的退变路径不同所引起, 此外还可能与体系含水量有关. 峰期温压条件及其地热梯度(6~7℃km~(-1))表明科克苏河流域出露的高压变质岩石同样经历了冷俯冲榴辉岩相变质作用, 它与西端的昭苏境内的榴辉岩-蓝片岩带相连, 构成了东西向长约200 km 的榴辉岩相变质带. 但在该区并未发现超高压变质矿物, 说明西南天山东段的科克苏河一带可能没有俯冲到达发生超高压变质作用的深度.