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National Science Review 2024年第1期11卷 8-10页

作者： David j.Bottjer Department of Earth Sciences University of Southern California

The defining feature of a mass extinction and its associated recovery is the global amount of extinction that occurred[1]. However, there is finer-scale detail to the story, as seen in the ongoing modern mass extinction(the sixth mass extinction), which exhibits variable effects among marine ecosystems and environments, and hence geographic areas [1].

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Review of current method to determine outburst threshold limits in Australian underground coal mines

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International journal of Mining Science and Technology 2019年第6期29卷 859-865页

作者： Dennis j.Black CoalGAS Department of Civil Mining and Environmental Engineering University of Wollongong

Desorption rate index(DRI)was presented to the Australian underground coal industry in 1995 as a means for determining outburst threshold limits for Australian coal *** is a measure of the gas volume released from a coal sample in the first 30 s of crushing during the Q3 stage of gas content testing,multiplied by the ratio between measured Q3 and *** were identified between QM and DRI for both CO2 and CH4 rich coal samples collected from the Bulli Seam at West Cliff Colliery and that identified relationship was referred to as the Bulli Seam *** outburst mining gas content threshold limit values specified for the Bulli Seam at that time,when applied to the QM-DRI Bulli Seam benchmark,was shown to closely align with a DRI value of 900(DRI900),for both CO2 and CH4 rich seam gas *** Australian coal industry adopted the DRI900 as the basis for determining outburst gas content TLV for Australian coal *** mining experience in Australia has shown that gas content is not the only significant factor that impacts outburst risk,as all significant outburst events have been associated with abnormal geological conditions,such as faults and ***,assessing the potential application of additional outburst risk factors,to accurately define outburst risk zones,set safe mining threshold levels,and determine appropriate mining controls,warrants further *** Australian coal mines have implemented mining procedures enabling mining to continue in areas with gas content greater than the TLV determined using the DRI900 approach,without inducing an *** is a broad lack of understanding among Australian coal mine operators as to the procedure and calculations used to determine ***,there has been growing concern regarding the accuracy and validity of the DRI900 method for determining outburst TLV.A comprehensive set of gas data has been collected from Australian coal seams,including the Bulli Seam,and t

关键词： Outburst Desorption rate DRI Threshold limit

Global weirding at mass extinction horizons

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National Science Review 2024年第1期11卷 10-12页

作者： Gregory j.Retallack Department of Earth Sciences University of Oregon

A strong motivation for studying mass extinctions is understanding how current climatic and biodiversity crises will affect creatures living on land such as ourselves. Perhaps the question is: how bad can it get? In that case, terrestrial Permian-Triassic mass extinctions are an irresistible worst-case scenario [1].

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Why Marginal Pricing?

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journal of Modern Power Systems and Clean Energy 2023年第3期11卷 693-697页

作者： Antonio j.Conejo Department of Integrated Systems Engineering and the Department of Electrical and Computer Engineering The Ohio State UniversityColumbusOhio 43210USA

Under perfect competition,marginal pricing results in short-term efficiency and the subsequent right short-term price ***,the main reason for the adoption of marginal pricing is not the above,but investment cost *** is,the fact that the profits obtained by infra-marginal technologies(technologies whose production cost is below the marginal price)allow them just to recover their investment *** the other hand,if the perfect competition assumption is removed,investment over-recovery or under-recovery generally occurs for infra-marginal technologies.

关键词： Electricity market marginal pricing investment cost recovery maximum social welfare right spatial and temporal price signals

Characterization of mudrocks:a practical application of advanced laboratory testing

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journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第1期12卷 1-14页

作者： Richard j.jARDINE Department of Civil and Environmental Engineering Imperial College London

An integrated approach to geomaterial characterization is advocated that combines geology, in-situ testing, fabric studies, routine index experiments and advanced laboratory testing. It is shown that advanced laboratory testing can explore features such as kinematic yielding and anisotropy in stiffness or shear strength that would otherwise be impossible to quantify. A detailed study performed in London clay at the new Heathrow Terminal 5 site is used to illustrate the arguments made. It is shown that the London clay has strong anisotropy in stiffness, is highly non-linear over the strain range of engineering interest, has markedly anisotropic shear strength characteristics and exhibits a pronounced degree of brittleness. These features can impact significantly on the practical design and analysis of civil engineering works including shallow and deep foundations, tunnels and excavations, and the stability of slopes.

关键词： Mudrock Fabric Anisotropy Hollow cylinder tests

Two distinct Paleozoic metamorphic events in the Tarim-North China Collage

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National Science Review 2023年第2期10卷 7-8页

作者： jérémie Soldner State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences CAS Center for Excellence in Deep Earth Science

The Central Asian Or ogenic Belt(CAOB) [1],which includes the Altaids in Central and Northern Asia [2],is the largest accretionary orogen formed during the subduction of the Paleo-Asian Ocean and the Panthalassa Ocean in the period of the Late Proterozoic to Late Paleozoic [3].Closure of the Paleo-Asian Ocean is attributed to the northward drift of the North China and Tarim cratons leading to the massive shortening and oroclinal buckling of the CAOB accretionary system in the Permian [4].

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Surface Modification of Nanometer Silica by N, N'-dicyclohexyl- carbodiimide Mediated Amidation

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Chinese Chemical Letters 2001年第10期12卷 933-934页

作者： Guo, ZX Yu, j Yu, j Tsing Hua Univ Dept Chem Engn Inst Polymer Sci & Engn Beijing 100084 Peoples R China

A potentially versatile procedure for surface modification of nanometer silica is illustrated by N, N-dicyclohexylcarbodiimide (DCC) mediated amidation of stearic acid.

关键词： Nanometer silica surface modification DCC acid amidation.

Unimodal Sequences of Gorenstein Ideals of Codimension 4

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Acta Mathematica Sinica,English Series 1998年第4期14卷 563-568页

作者： Hyoung j. Ko Department of Mathematics. Yonsei University 134 Shinchon-dong Seodaemun-gu. Seoul Korea 120-749

We present Gorenstein ideals of condimension 4 which have unimodal Hilbert functions.

关键词： k-configuration Hilbert function Minimal free resolution Gorenstein ideal of codimension 4

The role of the Mg_(17)Al_(12)-phase in the high-pressure die-cast magnesium-aluminum alloy system

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journal of Magnesium and Alloys 2023年第11期11卷 4235-4246页

作者： j.P.Weiler Meridian Lightweight Technologies Canada

The Mg_(17)Al_(12)β-phase is highly influential to the performance of magnesium-aluminum high-pressure die-casting alloys. Numerous studies have investigated the effect of this phase on the room temperature and elevated-temperature mechanical properties as well as the corrosion,flammability, thermal conductivity and castability performance. This work summarizes the results of these works, as well as the studies that describe control of the Mg_(17)Al_(12)-phase through alloying additions that modify the microstructure and resulting alloy performance. The results of this work can be used as a basis for the development of alloying additions that enable modifications to the performance of high-pressure die-cast magnesium-aluminum-based alloys.

关键词： Magnesium alloys HPDC Alloy development Properties

Methylation status of p16 gene in colorectal carcinoma and normal colonic mucosa

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World journal of Gastroenterology 1999年第5期5卷 451-454页

作者： Zhang j Lai MD Chen j Hangzhou Railway Cent Hosp Dept Clin Pathol Hangzhou 310000 Zhejiang Provin Peoples R China Zhejiang Univ Sch Med Dept Pathol Hangzhou 310006 Zhejiang Provin Peoples R China

INTRODUCTIONp16 gene (also known as MTS-1, INK4a, CDKN2A), located on chromosome 9p21, is a G1-specific cell-cycle regulatory gene. It is composed of three exons, which encode 156 amino acids[1]. The gene is frequently inactivated in many human cancers. Unlike other tumor-suppressor genes that are commonly inactivated by point mutations, small homozygous deletions and methylation of the promoter represent the major mechanism of p16 gene inactivation[2,3]. In the Western countries, colorectal carcinoma ranks first among malignant tumors. The mortality from colorectal carcinoma has been rapidly growing in China in the last two to three decades. The genetic alterations involved in this tumor are still unclear. Rare mutation and infrequent deletion of p16 gene in primary colorectal carcinoma has been widely reported[4]. There were a few papers on p16 gene methylation in colorectal carcinoma, but the results were contradictory[5,6]. In this study, we have examined a total of 60 samples of colorectal carcinoma and paired 60 samples of the normal colonic mucosa for methylation by means of PCR-based methylation assay. There is infrequent methylation in the promoter of p16 gene both in colorectal carcinoma and normal colonic mucosa. The methylation status in 5′ CpG island of p16 gene in colorectal carcinoma is not related to the clinical pathologic parameters of these tumors.

关键词： Colonic mucosa colorectal neoplasms p16 gene methylation