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Mobility and dynamic erosion process of granular flow:insights from numerical investigation using material point method
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作者 YU Fangwei SU Lijun +1 位作者 LI Xinpo ZHAO Yu 《Journal of Mountain Science》 SCIE CSCD 2024年第8期2713-2738,共26页
In order to understand the dynamics of granular flow on an erodible base soil,in this paper,a series of material point method-based granular column collapse tests were conducted to investigate numerically the mobility... In order to understand the dynamics of granular flow on an erodible base soil,in this paper,a series of material point method-based granular column collapse tests were conducted to investigate numerically the mobility and dynamic erosion process of granular flow subjected to the complex settings,i.e.,the aspect ratio,granular mass,friction and dilatancy resistance,gravity and presence of water.A set of power scaling laws were proposed to describe the final deposit characteristics of granular flow by the relations of the normalized run-out distance and the normalized final height of granular flow against the aspect ratio,being greatly affected by the complex geological settings,e.g.,granular mass,the friction and dilatancy resistance of granular soil,and presence of water in granular flow.An index of the coefficient of friction of granular soil was defined as a ratio of the target coefficient of friction over the initial coefficient of friction to quantify the scaling extent of friction change(i.e.,friction strengthening or weakening).There is a characteristic aspect ratio of granular column corresponding to the maximum mobility of granular flow with the minimum index of the apparent coefficient of friction.The index of the repose coefficient of friction of granular flow decreased gradually with the increase in aspect ratio because higher potential energy of granular column at a larger aspect ratio causes a larger kinetic energy of granular soil to weaken the friction of granular soil as a kind of velocity-related friction weakening.An increase in granular mass reduces gradually the indexes of the apparent and repose coefficients of friction of granular soil to enhance the mobility of granular flow.The mobility of granular flow increases gradually with the decrease in friction angle or increase in dilatancy angle of granular soil.However,the increase of gravity accelerates granular flow but showing the same final deposit profile without any dependence on gravity.The mobility of granular flow increases gradually by lowering the indexes of the apparent and repose coefficients of friction of granular flow while changing the surroundings,in turn,the dry soil,submerged soil and saturated soil,implying a gradually increased excessive mobility of granular flow with the friction weakening of granular soil.Presence of water in granular flow may be a potential catalyzer to yield a long run-out granular flow,as revealed in comparison of water-absent and water-present granular flows.In addition,the dynamic erosion and entrainment of based soil induced by granular flow subjected to the complex geological settings,i.e.,the aspect ratio,granular mass,gravity,friction and dilatancy resistance,and presence of water,were comprehensively investigated as well. 展开更多
关键词 Column collapse Granular flow Granular soil Material point method MOBILITY Numerical tests
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Application of Rollout Strategy to Test Points Selection for Integer-Coded Fault Wise Table 被引量:4
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作者 Cheng-Lin Yang Shu-Lin Tian Bing Long 《Journal of Electronic Science and Technology of China》 2009年第4期308-311,共4页
Test points selection for integer-coded fault wise table is a discrete optimization problem. The global minimum set of test points can only be guaranteed by an exhaustive search which is eompurationally expensive. In ... Test points selection for integer-coded fault wise table is a discrete optimization problem. The global minimum set of test points can only be guaranteed by an exhaustive search which is eompurationally expensive. In this paper, this problem is formulated as a heuristic depth-first graph search problem at first. The graph node expanding method and rules are given. Then, rollout strategies are applied, which can be combined with the heuristic graph search algorithms, in a computationally more efficient manner than the optimal strategies, to obtain solutions superior to those using the greedy heuristic algorithms. The proposed rollout-based test points selection algorithm is illustrated and tested using an analog circuit and a set of simulated integer-coded fault wise tables. Computa- tional results are shown, which suggest that the rollout strategy policies are significantly better than other strategies. 展开更多
关键词 Heuristic graph search integer-coded fault wise table optimization rollout strategy test points selection.
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Principle and operation of Jing-well point temperatures' test 被引量:1
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作者 Li-Hao Chen 《TMR Theory and Hypothesis》 2019年第3期212-218,共7页
Principle and operation of Jing-well point temperatures' test is a method to diagnose and treat diseases by measuring and comparing the symmetrical Jing-well point temperature of human body 12 meridians.It is an i... Principle and operation of Jing-well point temperatures' test is a method to diagnose and treat diseases by measuring and comparing the symmetrical Jing-well point temperature of human body 12 meridians.It is an important supplement to traditional Chinese medicine four diagnoses. The theoretical basis are that the Jing-well is closely related to Meridians and Viscera, the basic traditional Chinese medicine principle of 'governing exterior to infer interior' and the balancing phenomenon of Meridians. In this paper, the operation steps and treatment measures of Jing-well point temperatures' test are put forward, and 2 successful cases are given. At the end of this paper, the prospect of this method is discussed. 展开更多
关键词 Jing-well point temperatures' test Traditional Chinese medicine diagnosis PRINCIPLE Operation STEPS
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Selection of Minimal Test Points Set for Integer-Coded Fault Wise Table 被引量:1
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作者 Shu-Lin Tian Cheng-Lin Yang Bing Long 《Journal of Electronic Science and Technology of China》 2009年第4期312-316,共5页
Test points selection for integer-coded fault wise table is a discrete optimization problem. On one hand, traditional exhaustive search method is computationally expensive. On the other hand, the space complexity of t... Test points selection for integer-coded fault wise table is a discrete optimization problem. On one hand, traditional exhaustive search method is computationally expensive. On the other hand, the space complexity of traditional exhaustive is low. A tradeoff method between the high time complexity and low space complexity is proposed. At first, a new fault-pair table is constructed based on the integer-coded fault wise table. The fault-pair table consists of two columns: one column represents fault pair and the other represents test points set that can distinguish the corresponding faults. Then, the rows are arranged in ascending order according to the cardinality of corresponding test points set. Thirdly, test points in the top rows are selected one by one until all fault pair are isolated. During the test points selection process, the rows that contain selected test points are deleted and then the dimension of fault-pair table decreases gradually. The proposed test points selection algorithm is illustrated and tested using an integercoded fault wise table derived from a real analog circuit. Computational results suggest show policies are better than the exhaustive strategy. 展开更多
关键词 Fault-pair table integer-coded fault wise table optimization test points selection.
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Damage Position of Concrete Beam Based on Test of Even Change Point
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作者 张开鹏 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2004年第3期72-73,共2页
The quantitative analysis of damage position of concrete beam is established.The method of damage position free of models used in this paper is based on the variations of strain mode and test of even change point.The ... The quantitative analysis of damage position of concrete beam is established.The method of damage position free of models used in this paper is based on the variations of strain mode and test of even change point.The discrete model and the position criterion are presented.Numerical example is conducted,the result demonstrates that the method of damage position is correct and effective. 展开更多
关键词 test of even change point strain mode damage position
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Reusing Test Cases Based on the Function Point
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作者 张娟 童维勤 +2 位作者 蔡立志 黄文彬 HWANG Jenq-Neng 《Journal of Donghua University(English Edition)》 EI CAS 2014年第4期441-446,共6页
Reusing test cases from existing test case library is quite common in the software testing field. Testing practice tells us that there is a strong relationship between the granularity of a function unit under testing ... Reusing test cases from existing test case library is quite common in the software testing field. Testing practice tells us that there is a strong relationship between the granularity of a function unit under testing and that of the test case. A function unit with small granularity usually results in the test cases with the same small granularity. Therefore a test case defined as the function point,i. e.,the smallest size function unit,was provided for the first time.Though test cases with smaller granularity usually have better reusability,the cost of accurately reusing and integrating such test cases is also higher. In order to balance the test case reusability and the cost of test case reuse,a novel test case reuse model based on the function point was proposed in this paper. In this model,a reusable test case for specification-based testing was defined and some reuse strategies and three formal reuse methods were given. Finally,the complete automatic software process was realized by a reusing generation tool. The new method has improved reuse accuracy,while greatly enhances the software productivity. 展开更多
关键词 function point function unit test case test case suite REUSE RG tool Z specification language
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Process of Designing Robust, Dependable, Safe and Secure Software for Medical Devices: Point of Care Testing Device as a Case Study
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作者 Sivanesan Tulasidas Ruth Mackay +3 位作者 Pascal Craw Chris Hudson Voula Gkatzidou Wamadeva Balachandran 《Journal of Software Engineering and Applications》 2013年第9期1-13,共13页
This paper presents a holistic methodology for the design of medical device software, which encompasses of a new way of eliciting requirements, system design process, security design guideline, cloud architecture desi... This paper presents a holistic methodology for the design of medical device software, which encompasses of a new way of eliciting requirements, system design process, security design guideline, cloud architecture design, combinatorial testing process and agile project management. The paper uses point of care diagnostics as a case study where the software and hardware must be robust, reliable to provide accurate diagnosis of diseases. As software and software intensive systems are becoming increasingly complex, the impact of failures can lead to significant property damage, or damage to the environment. Within the medical diagnostic device software domain such failures can result in misdiagnosis leading to clinical complications and in some cases death. Software faults can arise due to the interaction among the software, the hardware, third party software and the operating environment. Unanticipated environmental changes and latent coding errors lead to operation faults despite of the fact that usually a significant effort has been expended in the design, verification and validation of the software system. It is becoming increasingly more apparent that one needs to adopt different approaches, which will guarantee that a complex software system meets all safety, security, and reliability requirements, in addition to complying with standards such as IEC 62304. There are many initiatives taken to develop safety and security critical systems, at different development phases and in different contexts, ranging from infrastructure design to device design. Different approaches are implemented to design error free software for safety critical systems. By adopting the strategies and processes presented in this paper one can overcome the challenges in developing error free software for medical devices (or safety critical systems). 展开更多
关键词 point of CARE testing System Architecture Safety CRITICAL Systems SOFTWARE Development
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Security Framework for Managing Data Security within Point of Care Tests
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作者 Sivanesan Tulasidas Ruth Mackay +1 位作者 Chris Hudson Wamadeva Balachandran 《Journal of Software Engineering and Applications》 2017年第2期174-193,共20页
Point of Care (PoC) devices and systems can be categorized into three broad classes (CAT 1, CAT 2, and CAT 3) based on the context of operation and usage. In this paper, the categories are defined to address certain u... Point of Care (PoC) devices and systems can be categorized into three broad classes (CAT 1, CAT 2, and CAT 3) based on the context of operation and usage. In this paper, the categories are defined to address certain usage models of the PoC device. PoC devices that are used for PoC testing and diagnostic applications are defined CAT 1 devices;PoC devices that are used for patient monitoring are defined as CAT 2 devices (PoCM);PoC devices that are used for as interfacing with other devices are defined as CAT 3 devices (PoCI). The PoCI devices provide an interface gateway for collecting and aggregating data from other medical devices. In all categories, data security is an important aspect. This paper presents a security framework concept, which is applicable for all of the classes of PoC operation. It outlines the concepts and security framework for preventing security challenges in unauthorized access to data, unintended data flow, and data tampering during communication between system entities, the user, and the PoC system. The security framework includes secure layering of basic PoC system architecture, protection of PoC devices in the context of application and network. Developing the security framework is taken into account of a thread model of the PoC system. A proposal for a low-level protocol is discussed. This protocol is independent of communications technologies, and it is elaborated in relation to providing security. An algorithm that can be used to overcome the threat challenges has been shown using the elements in the protocol. The paper further discusses the vulnerability scanning process for the PoC system interconnected network. The paper also presents a four-step process of authentication and authorization framework for providing the security for the PoC system. Finally, the paper concludes with the machine to machine (M2M) security viewpoint and discusses the key stakeholders within an actual deployment of the PoC system and its security challenges. 展开更多
关键词 point of CARE testing Data SECURITY SECURITY Framework THREAT Model
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Bamboo Taper Effect on Center Point Bending Test
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作者 Naresworo Nugroho Effendi Tri Bahtiar 《Journal of Physical Science and Application》 2012年第9期386-391,共6页
Bamboo became the best material choice for sustainable construction because it is fully renewable materials. Indonesian people traditionally choose bamboo for their housing since a long time ago. Bamboo stems usually ... Bamboo became the best material choice for sustainable construction because it is fully renewable materials. Indonesian people traditionally choose bamboo for their housing since a long time ago. Bamboo stems usually have unique shape. Its geometrical shape assumed as tapered hollow pipe. This study aims to find the effect of bamboo taper to its strength properties on center point bending test. The ratio between the Modulus of Rupture (S~) calculated in the center point, and the maximum bending stress along the beam is called strength ratio of taper (Ct). The theoretical calculation results Ct value is 1 if the taper lower than 0.023, while Ct value become lower if the taper is higher than 0.023. The survey on Ampel (Bambusa vulgaris Schrad.), Tali (Gigantochloa apus (BI. Ex Schult. f) Kurz), Gombong (Gigantochloa verticillata (Willd.) Munro), and Mayan (Gigantochloa robusta Kurz.) found that the overall taper range is -0.0047-0.0088 and 0-0.0127 for inner and outer taper respectively. On that overall range the Ct value is always 1, so it is reasonable to ignore the taper effect on one point bending test. 展开更多
关键词 Bamboo taper strength ratio one point bending test.
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Interpretation of data and treatment of Jing-well point temperatures test
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作者 Lei-Ming Wang Kang Tan Li-Hao Chen 《TMR Theory and Hypothesis》 2019年第4期260-266,共7页
The Jing-well point temperatures test method is a method to diagnose and guide the treatment of diseases by measuring the subjects' symmetrical well point temperature. it is improved from the method of knowing hea... The Jing-well point temperatures test method is a method to diagnose and guide the treatment of diseases by measuring the subjects' symmetrical well point temperature. it is improved from the method of knowing heat sensitivity. The application of Jing-well point temperatures test method is wide, and it can be used in internal and external gynecology and pediatrics and facial features department. at the same time, it has the advantage of objective and accurate diagnosis. The old law has some shortcomings, such as poor intuition, unavoidable omission of information, incomplete interpretation of information and so on. In this paper, Excel software is used to transform the data into line chart form, which improves the intuition and comprehensiveness of this method, so that the data can be better interpreted and used. It is newly proposed in this article that in addition to observing the longitudinal di fference of well point temperature, more attention should be paid to the horizontal contrast difference of well point temperature in different meridians. The article also summarizes a number of treatment methods, including acupuncture, moxa moxibustion, cupping and scraping, and the selection of acupoints, including mother acupoints, tenderness points and heat-sensitive moxibustion, so that doctors can combine traditional Chinese medicine professional knowledge in clinic. 展开更多
关键词 Jing-well point temperatures test Meridian diagnostic methods Line graphs DATA Teatment
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Optimal Test Points Selection Based on Multi-Objective Genetic Algorithm
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作者 Yong Zhang Xi-Xiang Chen Guan-Jun Liu Jing Qiu Shu-Ming Yang 《Journal of Electronic Science and Technology of China》 2009年第4期317-321,共5页
A new approach to select anoptimal set of test points is proposed. The described method uses fault-wise table and multi-objective genetic algorithm to find the optimal set of test points. First, the fault-wise table i... A new approach to select anoptimal set of test points is proposed. The described method uses fault-wise table and multi-objective genetic algorithm to find the optimal set of test points. First, the fault-wise table is constructed whose entries are measurements associated with faults and test points. The selection of optimal test points is transformed to the selection of the columns that isolate the rows of the table. Then, four objectives are described according to practical test requirements. The multi-objective genetic algorithm is explained. Finally, the presented approach is illustrated by a practical example. The results indicate that the proposed method can efficiently and accurately find the optimal set of test points and is practical for large scale systems. 展开更多
关键词 Design for testability multi-objective genetic algorithm system testing test points selection.
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Evaluation of a Plasma hCG Method for Point of Care Testing with the Aim of Shortening Test-Turnaround-Times
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作者 Anna-Karin Wikstrom Magnus Hagmar +1 位作者 Goran Ronquist Anders Larsson 《Open Journal of Obstetrics and Gynecology》 2015年第6期341-343,共3页
Objective: To examine the correlation between plasma hCG results obtained with the new i-STAT&reg hCG point of care test with those concomitantly obtained from the central hospital laboratory utilizing the same pa... Objective: To examine the correlation between plasma hCG results obtained with the new i-STAT&reg hCG point of care test with those concomitantly obtained from the central hospital laboratory utilizing the same patient samples. Methods: Prospective cross-sectional laboratory test evaluation. We compared plasma hCG results obtained with the i-STAT&reg hCG test (Abbott Point of Care, Princeton, NJ, USA) with Architect Ci8200 (Abbott Laboratories, Abbott Park, IL, USA). We also calculated the total coefficient of variation (CV) for the i-STAT&reg method. Results: The two methods showed a good linear correlation (R2 = 0.994;slope 1.03) and CV for the i-STAT&reg method was 2.1% - 5.2%. Conclusion: We suggest that the i-STAT&reg hCG blood assay could be used as a complement to urine hCG assays in clinical situations when rapid test results are needed and urine is not available. 展开更多
关键词 Human Chorionic Gonadotropin PREGNANCY Method Evaluation point of Care test
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The Power of Change-Point Test for Two-Phase Regression
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作者 To Van Ban Nguyen Thi Quyen 《Applied Mathematics》 2014年第19期2994-3000,共7页
In this paper, the roughness of the model function to the basis functions and its properties have been considered. We also consider some conditions to take the limit of the roughness when the observations are i.i.d. A... In this paper, the roughness of the model function to the basis functions and its properties have been considered. We also consider some conditions to take the limit of the roughness when the observations are i.i.d. An explicit formula to calculate the power of change-point test for the two phases regression through the roughness was obtained. 展开更多
关键词 CHANGE-point test The POWER The ROUGHNESS RANDOM Design
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A Point-of-Care Test System for Biochemical Blood Analysis Based on ADUC824
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作者 Hui Wang Qing Tian +3 位作者 Liying Jiang Chunxiu Liu Zonghui Guo Xinxia Cai 《稀有金属材料与工程》 SCIE EI CAS CSCD 北大核心 2006年第A03期75-79,共5页
A point-of-care test system has been studied in this paper.It was used to determine substances in blood such as Hemoglobin (HB),Aspartate Aminotransferase (AST),Creatine Kinase (CK) and so on.Based on the principle ... A point-of-care test system has been studied in this paper.It was used to determine substances in blood such as Hemoglobin (HB),Aspartate Aminotransferase (AST),Creatine Kinase (CK) and so on.Based on the principle of amperometric determination,the research on detecting weak current signals was carried on.At the same time as to the weak signals (nA level),magnifying,sampling and processing the signals were also studied.Controlled by ADUC824 and assisted by other units, every substance could be determined automatically and rapidly integrated with the corresponding biosensor.In the experiment, the minimum detectable current of the instrument (YT2005-1) is 0.2 nA.With regard to the 1 nA which the experiment demanded,it could be up to the mustard.And the system can provide results in 180 s with a long term stability. 展开更多
关键词 point-of-care test ADUC824 weak signals HB AST and CK
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Point-of-Care Testing vs. Laboratory Testing during High Patient Volume Situations
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作者 Jonathan McCoy Robert Eisenstein +5 位作者 Channing Hui Greg Corcoran Chris Kilker Pamela Ohman-Strickland Mark Merlin Clifton Lacy 《Open Journal of Emergency Medicine》 2019年第4期49-56,共8页
Introduction: Our aim was to determine what patient volume, if any, in-laboratory testing provides results faster than Point-of-Care-Testing (POCT). Methods: To evaluate POCT effectiveness during high volume situation... Introduction: Our aim was to determine what patient volume, if any, in-laboratory testing provides results faster than Point-of-Care-Testing (POCT). Methods: To evaluate POCT effectiveness during high volume situations, POCT was compared to in-laboratory testing during busy periods with large numbers of patients. Our setting was an urban level 1 trauma center with an academic emergency medicine department (ED) and annual patient volume of 70,000. Patients seen requiring laboratory testing during peak volume between 11 a.m. and 7 p.m. were enrolled over a five-week period. One tube of blood was sent to the laboratory and the other tube was run in the ED using POCT. Turnaround time was recorded as time from when the tube was received to when the result was available. We also completed a time-motion study to assess the number of POCT machines that would be needed to process the entire average hourly hospital laboratory volume. Results: We collected 539 hematology and chemistry specimens. The POCT group was significantly faster than in-laboratory testing, with mean POCT [complete blood count (CBC) and chemistry] 3.5 minutes compared to in-laboratory CBC test time of 30.9 minutes and chemistry test time of 55 minutes. As the volume of samples peaked, there was a slight but insignificant decrease in POCT turnaround time. If POCT was used to process the entire average hospital laboratory volume which approached 54 samples an hour, 3 POCT machines would be necessary to maintain turnaround times. Conclusion: Even during ED high volume situations, POCT provided results significantly faster than in-laboratory testing. 展开更多
关键词 point-OF-CARE testing EMERGENCY DEPARTMENT DISASTER MEDICINE
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Point-of-Care Testing Using Three Dimensional Optical Biosensor Based on Microfluidic Technology
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作者 Chunxiu Liu Haoyuan Cai +4 位作者 Jian Jia Tianyang Cao Tong Li Tianjun Ma Chang Liu 《Journal of Biosciences and Medicines》 2016年第12期56-61,共6页
We have presented a three dimensional optical protein chip that fulfills the demanding for point-of-care diagnostics in terms of ease-of-use (one step assay), miniaturization (5 μl). The artful combination of magneti... We have presented a three dimensional optical protein chip that fulfills the demanding for point-of-care diagnostics in terms of ease-of-use (one step assay), miniaturization (5 μl). The artful combination of magnetic nanoparticles on chip and total internal reflection imaging (TIRI) technology permits the sensitive and rapid detection of hs-CRP (high-sensitivity C-reactive protein). The whole test was complete within 10 min using “all in one step” assay with a limit of detection of 0.1 ng/mL hs-CRP. The measuring range for hs-CRP could be extended to 10 ng/mL. The chip can also be used to detect more parameters in blood samples. 展开更多
关键词 point-of-Care testing (POCT) Three Dimensional Optical Chip HS-CRP
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Detecting Climate Change Trend, Size, and Change Point Date on Annual Maximum Time Series Rainfall Data for Warri, Nigeria
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作者 Masi G. Sam Ify L. Nwaogazie +2 位作者 Chiedozie Ikebude Chigozie Dimgba Diaa W. El-Hourani 《Open Journal of Modern Hydrology》 2023年第3期165-179,共15页
The study focused on the detection of indicators of climate change in 24-hourly annual maximum series (AMS) rainfall data collected for 36 years (1982-2017) for Warri Township, using different statistical methods yiel... The study focused on the detection of indicators of climate change in 24-hourly annual maximum series (AMS) rainfall data collected for 36 years (1982-2017) for Warri Township, using different statistical methods yielded a statistically insignificant positive mild trend. The IMD and MCIMD downscaled model’s time series data respectively produced MK statistics varying from 1.403 to 1.4729, and 1.403 to 1.463 which were less than the critical Z-value of 1.96. Also, the slope magnitude obtained showed a mild increasing trend in variation from 0.0189 to 0.3713, and 0.0175 to 0.5426, with the rate of change in rainfall intensity at 24 hours duration as 0.4536 and 0.42 mm/hr.year (4.536 and 4.2 mm/decade) for the IMD and the MCIMD time series data, respectively. The trend change point date occurred in the year 2000 from the distribution-free CUSUM test with the trend maintaining a significant and steady increase from 2010 to 2015. Thus, this study established the existence of a trend, which is an indication of a changing climate, and satisfied the condition for rainfall Non-stationary intensity-duration-frequency (NS-IDF) modeling required for infrastructural design for combating flooding events. 展开更多
关键词 Climate Change Annual Maximum Series Statistical test Rainfall Trend and Size Change point Date
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Comparative Analysis of Climatic Change Trend and Change-Point Analysis for Long-Term Daily Rainfall Annual Maximum Time Series Data in Four Gauging Stations in Niger Delta
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作者 Masi G. Sam Ify L. Nwaogazie +4 位作者 Chiedozie Ikebude Jonathan O. Irokwe Diaa W. El Hourani Ubong J. Inyang Bright Worlu 《Open Journal of Modern Hydrology》 2023年第4期229-245,共17页
The aim of this study is to establish the prevailing conditions of changing climatic trends and change point dates in four selected meteorological stations of Uyo, Benin, Port Harcourt, and Warri in the Niger Delta re... The aim of this study is to establish the prevailing conditions of changing climatic trends and change point dates in four selected meteorological stations of Uyo, Benin, Port Harcourt, and Warri in the Niger Delta region of Nigeria. Using daily or 24-hourly annual maximum series (AMS) data with the Indian Meteorological Department (IMD) and the modified Chowdury Indian Meteorological Department (MCIMD) models were adopted to downscale the time series data. Mann-Kendall (MK) trend and Sen’s Slope Estimator (SSE) test showed a statistically significant trend for Uyo and Benin, while Port Harcourt and Warri showed mild trends. The Sen’s Slope magnitude and variation rate were 21.6, 10.8, 6.00 and 4.4 mm/decade, respectively. The trend change-point analysis showed the initial rainfall change-point dates as 2002, 2005, 1988, and 2000 for Uyo, Benin, Port Harcourt, and Warri, respectively. These prove positive changing climatic conditions for rainfall in the study area. Erosion and flood control facilities analysis and design in the Niger Delta will require the application of Non-stationary IDF modelling. 展开更多
关键词 Rainfall Time Series Data Climate Change Trend Analysis Variation Rate Change point Dates Non-Parametric Statistical test
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基于数字图像相关的地聚物混凝土轨枕的力学性能分析 被引量:1
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作者 韩宜康 王俊逸 +1 位作者 张睿哲 井国庆 《铁道科学与工程学报》 EI CAS CSCD 北大核心 2024年第1期116-124,共9页
随着混凝土轨枕在我国的广泛应用,混凝土的生产带来大量的能源消耗和碳排放。地聚物作为一种新型低碳材料,能在节能减碳的同时消耗矿渣和粉煤灰等固废。目前,针对地聚物应用于铁路轨枕的相关研究,如混合使用水泥与粉煤灰、矿渣的地聚物... 随着混凝土轨枕在我国的广泛应用,混凝土的生产带来大量的能源消耗和碳排放。地聚物作为一种新型低碳材料,能在节能减碳的同时消耗矿渣和粉煤灰等固废。目前,针对地聚物应用于铁路轨枕的相关研究,如混合使用水泥与粉煤灰、矿渣的地聚物混凝土轨枕及其裂缝扩展特性的研究还比较有限。本文设计2种配合比的地聚物混凝土并制造成轨枕,使用数字图像相关(Digital Image Correlation)技术,在轨下截面的三点弯曲实验下分析2种配合比下轨枕挠度、裂缝扩展特性及裂缝宽度发展规律。研究结果表明,2种配合比地聚物混凝土轨枕的抗弯承载力均高于普通混凝土轨枕。相比于普通混凝土轨枕,地聚物混凝土轨枕在较低的静荷载作用下挠度较大,但随着荷载的增加轨枕挠度的增长速度较慢,刚度损失较小,弹性阶段延续的荷载区间更长,这种特征在配合比为Geo50的地聚物混凝土轨枕上更为显著。2种配合比的轨枕微裂纹萌生的荷载相近,分别为130 kN和120 kN。在较低荷载下2种轨枕裂缝扩展相差不大,在较高荷载下配合比为Geo100的地聚物轨枕的裂缝发展加快,裂缝宽度值和增长速度都大于Geo50。配合比为Geo100的地聚物混凝土轨枕主要表现为受弯正截面破坏,配合比为Geo50的地聚物混凝土轨枕主要表现为受剪斜拉破坏。掺入部分水泥代替矿渣和粉煤灰的地聚物能使所制成轨枕在较高的荷载下保持更高刚度和更缓慢的裂缝扩展速度,该方案有助于推动地聚物应用于混凝土轨枕,促进铁路双碳战略贯彻与实施。 展开更多
关键词 数字图像相关技术(DIC) 地聚物 地聚物混凝土轨枕 裂缝 三点抗弯试验
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应用于食品检测领域的分子即时检测技术研究进展 被引量:4
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作者 王薇 付群 +4 位作者 郑艳敏 王波 刘岩 刘佳 孙万平 《食品安全质量检测学报》 CAS 2024年第1期48-56,共9页
食品安全问题关系人类民生。为有效预防和控制食品安全风险,减少食品安全经济损失,迫切需要开发出针对食源性病原体、食物掺假、转基因作物的高特异性、高敏感性、快速的核酸检测技术。即时检测(point-of-care testing,POCT)作为一种新... 食品安全问题关系人类民生。为有效预防和控制食品安全风险,减少食品安全经济损失,迫切需要开发出针对食源性病原体、食物掺假、转基因作物的高特异性、高敏感性、快速的核酸检测技术。即时检测(point-of-care testing,POCT)作为一种新兴的快速检测手段,由于其检测速度快、操作简单、现场检查等特点,在食品检测领域应用广泛。本文首先介绍了POCT技术的发展历史,而后根据食品安全事件的特点,从食源性致病菌、食物掺假、转基因作物3个方向分析了食品检测的主要对象,阐述了分子POCT技术在食品检测领域的应用现状,最后对应用于食品检测领域的分子POCT技术存在的问题和解决办法进行了分析总结,对食品检测分子POCT技术的发展方向进行了展望。本文有助于进一步了解分子POCT技术在食品检测中的应用,并为分子POCT技术在食品快速检测中的研究和应用提供参考。 展开更多
关键词 食品检测 分子即时检测 食品安全 等温扩增技术 成簇规律间隔短回文重复序列及其相关系统检测技术
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