Carbonate reservoir patterns play an important role in the production performance of oil and gas wells,and it is usually classified through static data analysis which cannot reflect the actual well performance.This pa...Carbonate reservoir patterns play an important role in the production performance of oil and gas wells,and it is usually classified through static data analysis which cannot reflect the actual well performance.This paper takes the Tazhong No.1 gas field in the Tarim Basin,China as an example to investigate the classification of carbonate reservoirs.The classification method mainly combines well test analysis with production analysis—especially the Blasingame type curve method.Based on the characteristics of type curves for well test analysis and the Blasingame method,the relationship between the type curves and reservoir pattern was established.More than 20 wells were analyzed and the reservoirs were classified into 3 major patterns with 7 sub-classes.Furthermore,the classification results were validated by dynamic performance analysis of wells in the Tazhong No.1 gas field.On the basis of the classification results,well stimulation（i.e.water flooding in a single well） was carried out in three volatile-oil wells,and the oil recovery increased by up to 20%.展开更多
A novel test approach for interconnect resources （IRs） in field programmable gate arrays （FPGA） has been proposed.In the test approach,SBs （switch boxes） of IRs in FPGA has been utilized to test IRs.Furthermore,...A novel test approach for interconnect resources （IRs） in field programmable gate arrays （FPGA） has been proposed.In the test approach,SBs （switch boxes） of IRs in FPGA has been utilized to test IRs.Furthermore,configurable logic blocks （CLBs） in FPGA have also been employed to enhance driving capability and the position of fault IR can be determined by monitoring the IRs associated SBs.As a result,IRs can be scanned maximally with minimum configuration patterns.In the experiment,an in-house developed FPGA test system based on system-on-chip （SoC） hardware/software verification technology has been applied to test XC4000E family of Xilinx.The experiment results revealed that the IRs in FPGA can be tested by 6 test patterns.展开更多
In this paper,we consider testing the hypothesis concerning the means of two independent semicontinuous distributions whose observations are zero-inflated,characterized by a sizable number of zeros and positive observ...In this paper,we consider testing the hypothesis concerning the means of two independent semicontinuous distributions whose observations are zero-inflated,characterized by a sizable number of zeros and positive observations from a continuous distribution.The continuous parts of the two semicontinuous distributions are assumed to follow a density ratio model.A new two-part test is developed for this kind of data.The proposed test takes the sum of one test for equality of proportions of zero values and one conditional test for the continuous distribution.The test is proved to follow a 2 distribution with two degrees of freedom.Simulation studies show that the proposed test controls the type I error rates at the desired level,and is competitive to,and most of the time more powerful than two popular tests.A real data example from a dietary intervention study is used to illustrate the usefulness of the proposed test.展开更多
Background: We aim to determine the proportions and patterns of resistance to first-line drugs: isoniazid (H), rifampicin (R), ethambutol (E) and streptomycin (S) among pulmonary tuberculosis patients. Methods: Strain...Background: We aim to determine the proportions and patterns of resistance to first-line drugs: isoniazid (H), rifampicin (R), ethambutol (E) and streptomycin (S) among pulmonary tuberculosis patients. Methods: Strains were obtained from 1584 culture positive pulmonary tuberculosis patients. All specimens were inoculated into L?wenstein-Jensen media (LJ) and TK selective;drug susceptibility tests (DST) were performed for first-line drugs. Results: Multidrug resistant (MDR) were detected in 146 (9.2%) isolates. Three hundred (18.9%) isolates were resistant to H;220 (13.9%) to R;168 (10.6%) to S;137 (8.6%) to E. Any drug resistance was detected in 442 (27.9%) isolates. MDR rate was higher in male patients than females (P = 0.006). MDR rates were different according to the age groups (P = 0.02). The highest rate was in 35 - 44 years and the lowest rate was in 15 - 24 years. Conclusions: We found an association between middle age and male gender and MDR tuberculosis.展开更多
Background: Tuberculosis (TB) is an infectious disease caused by the bacillus Mycobacterium tuberculosis. Anti-tuberculosis drug resistance is an emerging health problem in Kenya and especially in Coastal region. This...Background: Tuberculosis (TB) is an infectious disease caused by the bacillus Mycobacterium tuberculosis. Anti-tuberculosis drug resistance is an emerging health problem in Kenya and especially in Coastal region. This is a major challenge in tuberculosis control. Diagnosis is based on Ziel-Neelsen staining alone and patients are treated without information on sensitivity patterns. Aim: This study aimed to determine drug susceptibility patterns of Mycobacterium tuberculosis in Coastal Kenya. Study Design: Hospital and laboratory based cross-sectional study was carried between April 2015 and July 2016 at Coast General Referral hospital;Tudor, Port-Reitz, Likoni Sub-County hospitals;Mlaleo, Kongowea and Mikindani health centers. Methodology: Sputum samples from patients with bacteriological confirmed TB on microscopy were cultured on Lowenstein Jensen (LJ) media. Strains of MTB complex from Lowenstein Jensen (LJ) slopes were subjected to drug susceptibility testing (DST) to first-line drugs including isoniazid (H), rifampicin (R), streptomycin (S) and Ethambutol (E) using proportional method on the Mycobacterium Growth Indicator Tube (MGIT) conventional method. Participants were offered diagnostic testing and counselling for HIV testing. Results: Drug sensitivity test was performed for a total of 210 Mycobacterium tuberculosis isolates for the first line anti-TB drugs. About seventy eight percent and twenty nine percent of the strains from new patients and previously treated patients were fully sensitive to all the drugs tested respectively. Prevalence of any resistance to one drug was 102 (48.6%, 95% CI: 20.45 - 28.23). Any single drug resistance was most frequent in isoniazid 30 (16.0%), Ethambutol 20 (10.0%), Streptomycin 18 (18.3%) and Rifampicin 4 (2.1%) in newly diagnosed patients. Among previously treated patients any resistance to streptomycin, ethambutol, isoniaziad and rifampicin was 10 (58.8%), 9 (52.9%), 7 (41.2%) and 4 (23.5%) respectively. Prevalence of MDR-TB defined as resistant to at least both isoniazid and rifampicin was 10 (4.8%) among new and previously treated patients respectively. Conclusion: The current study reveals that the overall resistance to first line anti-TB drugs was high. Although the rate of MDR-TB was relatively low, this signifies that conditions favouring the spread of MDR-TB are on high rise. Therefore, it is essential to address the problems of development of drug re-sistant strains of TB by establishing good TB programmes (DOTS). Patients’ adherence to anti-TB drugs and introducing drug sensitivity testing (DST) services at County level hospitals will minimize occurrence of drug resistant.展开更多
DDR3芯片是一种能最高支持1600 Mbps传输速率的高速存储器芯片,本文对该类芯片的功能描述,寄存器配置进行介绍,针对ATE(Automated Test Equipment,自动测试设备)测试机台设计了相应的硬件Loadboard,最后在ATE测试机台上进行了速度等级测...DDR3芯片是一种能最高支持1600 Mbps传输速率的高速存储器芯片,本文对该类芯片的功能描述,寄存器配置进行介绍,针对ATE(Automated Test Equipment,自动测试设备)测试机台设计了相应的硬件Loadboard,最后在ATE测试机台上进行了速度等级测试,测试结果验证了DDR3芯片在最高频率1600Mbps下的功能正确性,运用shmoo进行绘制眼图,分析DDR3的信号完整性,为DDR3芯片测试提供了一定的参考。展开更多
In this study, based on the data on the frequency of waterlogging events and the number of waterlogging days of 1,638 stations from 1961 to 2016, a variety of mathematical statistics methods were used to analyze the s...In this study, based on the data on the frequency of waterlogging events and the number of waterlogging days of 1,638 stations from 1961 to 2016, a variety of mathematical statistics methods were used to analyze the spatiotemporal evolution of waterlogging events in eastern China. The results showed that:① In terms of time, the annual frequency of waterlogging events and the number of waterlogging days in eastern China in 1961–2016 showed an increasing trend despite of fluctuations. In the interdecadal changes, the highest frequency of waterlogging events and the greatest number of waterlogging days occurred in the 1990s, and from the 1960s to the 1980s, the frequency of waterlogging events and the number of waterlogging days in eastern China showed a decreasing trend. There were 6-year and 30-year periodic variations in the frequency of waterlogging events and the number of waterlogging days in eastern China, and mutations occurred in 1991.② In terms of space, from 1961 to 2016, the areas with high frequency of waterlogging events in various years in eastern China were mainly South China, western and southern Yunnan, northern Jiangsu, southern Zhejiang, northern Fujian, junction areas between Hunan and Chongqing, northern Sichuan, and eastern Liaoning.③ In the spatial distribution of change trends and fluctuation characteristics, the frequency of waterlogging events and the number of waterlogging days in eastern China increased significantly in the southeastern coastal areas from 1961 to 2016, and the fluctuations of the frequency of waterlogging events and the number of waterlogging days in eastern China from 1961 to 2016 presented a spatial variation pattern of low in the southwest and high in the northwest.展开更多
Introduction:This study aimed to characterize the genetic diversity and antimicrobial resistance patterns of Campylobacter isolates collected throughout China from 2020 to 2023.Methods:Campylobacter isolates analyzed ...Introduction:This study aimed to characterize the genetic diversity and antimicrobial resistance patterns of Campylobacter isolates collected throughout China from 2020 to 2023.Methods:Campylobacter isolates analyzed in this study were obtained from the National Pathogen Identification Network Center database,maintained by the National Institute for Infectious Disease Control and Prevention of the Chinese Center for Disease Control and Prevention.Antimicrobial susceptibility testing(AST)was performedagainsteleven antimicrobial agents.Genomic characteristics were analyzed through comprehensive genome sequence analysis.Results:Between 2020 and 2023,the National Pathogen Identification Network documented 1,077 Campylobacter jejuni(C.jejuni)and 221 Campylobacter coli(C.coli)isolates.Most isolates originated from patients presenting with diarrhea.Antimicrobial susceptibility testing was conducted on 634 C.jejuni and165C.coli isolates.The tested isolates demonstrated high resistance rates to nalidixic acid(78.22%),ciprofloxacin(78.07%),and tetracycline(71.96%).Longitudinal analysis of antimicrobial susceptibility testing results revealed a declining resistance trend from 2020 to 2023.Whole genome sequences were obtained for 540 C.jejuni and 125 C.coli isolates within the database.Virulence factors and antibiotic resistance determinants were identified using the VFDB and CARD databases,respectively.Phylogenetic relationships were established through Snippy 4.0 software analysis based on core genome comparisons.Conclusions:This comprehensive analysis.describes the antibiotic resistance profiles and genetic characteristics of Campylobacter isolates collected through the Identification Network Database from 2020 to 2023,establishing a foundational framework for campylobacteriosis control and prevention strategies in China.展开更多
A leading position in the areas of testing,instrumentation and machine control has been established by members of the British Textile Machinery Association(BTMA)and a number of new developments in these fields will be...A leading position in the areas of testing,instrumentation and machine control has been established by members of the British Textile Machinery Association(BTMA)and a number of new developments in these fields will be showcased at this year’s ITMA Asia+CITME exhibition,which takes place in Singapore from October 28-31.“Many of our members are currently developing new technologies,either in-house or increasingly through joint projects,and there will be much to reveal by the time of ITMA Asia in Singapore,”says BTMA CEO Jason Kent.“Some of the most recent developments are really going beyond what has previously been possible.”展开更多
Advancements in semiconductor technology are making gate-level test generation more challenging. This is because a large amount of detailed structural information must be processed in the search process of automatic t...Advancements in semiconductor technology are making gate-level test generation more challenging. This is because a large amount of detailed structural information must be processed in the search process of automatic test pattern generation (ATPG). In addition, ATPG needs to deal with new defects caused by process variation when IC is shrinking. To reduce the computation effort of ATPG, test generation could be started earlier at higher abstraction level, which is in line with top-down design methodology that has become more popular nowadays. In this research, we employ Chen’s high-level fault model in the high-level ATPG. Besides shorter ATPG time as shown in many previous works, our study showed that high-level ATPG also contributes to test compaction. This is because most of the high-level faults correlate with the gate-level collapsed faults especially at input/output of the modules in a circuit. The high-level ATPG prototype used in our work is mainly composed by constraint-driven test generation engine and fault simulation engine. Experimental result showed that more reduced/compact test set can be generated from the high-level ATPG.展开更多
A variety of faulty radar echoes may cause serious problems with radar data applications,especially radar data assimilation and quantitative precipitation estimates.In this study,＂test pattern＂ caused by test signal...A variety of faulty radar echoes may cause serious problems with radar data applications,especially radar data assimilation and quantitative precipitation estimates.In this study,＂test pattern＂ caused by test signal or radar hardware failures in CINRAD （China New Generation Weather Radar） SA and SB radar operational observations are investigated.In order to distinguish the test pattern from other types of radar echoes,such as precipitation,clear air and other non-meteorological echoes,five feature parameters including the effective reflectivity data percentage （Rz）,velocity RF （range folding） data percentage （RRF）,missing velocity data percentage （RM）,averaged along-azimuth reflectivity fluctuation （RNr,z） and averaged along-beam reflectivity fluctuation （RNa,z） are proposed.Based on the fuzzy logic method,a test pattern identification algorithm is developed,and the statistical results from all the different kinds of radar echoes indicate the performance of the algorithm.Analysis of two typical cases with heavy precipitation echoes located inside the test pattern are performed.The statistical results show that the test pattern identification algorithm performs well,since the test pattern is recognized in most cases.Besides,the algorithm can effectively remove the test pattern signal and retain strong precipitation echoes in heavy rainfall events.展开更多
Kissing bonds are defects in the adhesive bonds with intimate contact of touching surface but considerably lowered shear strength. Their detection specifically in the aerospace area is so not satisfactory. Usually, ki...Kissing bonds are defects in the adhesive bonds with intimate contact of touching surface but considerably lowered shear strength. Their detection specifically in the aerospace area is so not satisfactory. Usually, kissing bonds are inconspicuous in ultrasonic C-scans. However, the determination of attributes in the time domain and the frequency domain of an ultrasound signal provides the opportunity to derive a pattern for bonded area. Deviations from the pattern found in inconspicuous bonding areas indicate kissing bonds. The survey described here deals with the manufacturing of adhesively joint samples that purposefully include kissing bonds, as well as potential solutions for detecting them through ultrasonic testing combined with pattern recognition. The properties of the epoxy-based adhesive were varied by changing the mixing ratios between resin and hardener. Samples with a mixing ratio far apart from the manufacturer’s recommendation with an inconspicuous appearance in a C-scan, but low shear strength values were taken for further evaluation. After a definition and learning phase, a 100 percent hit rate to separate good bondings from kissing bonds could be derived in a blind test. The discriminating feature found is due to the frequency shift between good and kissing bonds as well as the relative amplitude of the second peak.展开更多
This paper presents modeling tools based on Boolean satisfiability (SAT) to solve problems of test generation for combinational circuits. It exploits an added layer to maintain circuit-related information and value ju...This paper presents modeling tools based on Boolean satisfiability (SAT) to solve problems of test generation for combinational circuits. It exploits an added layer to maintain circuit-related information and value justification relations to a generic SAT algorithm. It dovetails binary decision graphs (BDD) and SAT techniques to improve the efficiency of automatic test pattern generation (ATPG). More specifically, it first exploits inexpensive reconvergent fanout analysis of circuit to gather information on the local signal correlation by using BDD learning, then uses the above learned information to restrict and focus the overall search space of SAT-based ATPG. Its learning technique is effective and lightweight. The experimental results demonstrate the effectiveness of the approach.展开更多
Pressure buildup testing can be used to analyze fracture network characteristics and conduct quantitative interpretation of relevant parameters for shale gas wells,thus providing bases for assessing the well productiv...Pressure buildup testing can be used to analyze fracture network characteristics and conduct quantitative interpretation of relevant parameters for shale gas wells,thus providing bases for assessing the well productivity and formulating proper development strategies.This study establishes a new well test interpretation model for fractured horizontal wells based on seepage mechanisms of shale reservoirs and proposes a method for identifying fracturing patterns based on the characteristic slopes of pressure buildup curves and curve combination patterns.The pressure buildup curve patterns are identified to represent three types of shale reservoirs in the Sichuan Basin,namely the moderately deep shale reservoirs with high pressure,deep shale reservoirs with ultra-high pressure,and moderately deep shale reservoirs with normal pressure.Based on this,the relationship between the typical pressure buildup curve patterns and the fracture network types are put forward.Fracturing effects of three types of shale gas reservoir are compared and analyzed.The results show that typical flow patterns of shale reservoirs include bilinear flow in primary and secondary fractures,linear flow in secondary fractures,bilinear flow in secondary fractures and matrix,and linear flow in matrix.The fracture network characteristics can be determined using the characteristic slopes of pressure buildup curves and curve combinations.The linear flow in early secondary fractures is increasingly distinct with an increase in primary fracture conductivity.Moreover,the bilinear flow in secondary fractures and matrix and the subsequent linear flow in the matrix occur as the propping and density of secondary fractures increase.The increase in the burial depth,in-situ stress,and stress difference corresponds to a decrease in the propping of primary fractures that expand along different directions in the shale gas wells in the Sichuan Basin.Four pressure buildup curve patterns exist in the Sichuan Basin and its periphery.The pattern of pressure buildup curves of shale reservoirs in the Yongchuan area can be described as 1/2/→1/4,indicating limited stimulated reservoir volume,poorly propped secondary fractures,and the forming of primary fractures that extend only to certain directions.The pressure buildup curves of shale reservoirs in the main block of the Fuling area show a pattern of 1/4/→1/2 or 1/2,indicating greater stimulated reservoir volume,well propped secondary fractures,and the forming of complex fracture networks.The pattern of pressure buildup curves of shale reservoirs in the Pingqiao area is 1/2/→1/4→/1/2,indicating a fracturing effect somewhere between that of the Fuling and Yongchuan areas.For reservoirs with normal pressure,it is difficult to determine fracture network characteristics from pressure buildup curves due to insufficient formation energy and limited liquid drainage.展开更多
基金financial support from"Major Projects about Carbonate Reservoirs of Petrochina (2008E-0610-08)""Young Innovation Fund Project of Research Institute of Petroleum Exploration and Development (2009-A-17-13)"
文摘Carbonate reservoir patterns play an important role in the production performance of oil and gas wells,and it is usually classified through static data analysis which cannot reflect the actual well performance.This paper takes the Tazhong No.1 gas field in the Tarim Basin,China as an example to investigate the classification of carbonate reservoirs.The classification method mainly combines well test analysis with production analysis—especially the Blasingame type curve method.Based on the characteristics of type curves for well test analysis and the Blasingame method,the relationship between the type curves and reservoir pattern was established.More than 20 wells were analyzed and the reservoirs were classified into 3 major patterns with 7 sub-classes.Furthermore,the classification results were validated by dynamic performance analysis of wells in the Tazhong No.1 gas field.On the basis of the classification results,well stimulation（i.e.water flooding in a single well） was carried out in three volatile-oil wells,and the oil recovery increased by up to 20%.
基金supported by the Key Techniques of FPGA Architecture under Grant No. 9140A08010106QT9201
文摘A novel test approach for interconnect resources （IRs） in field programmable gate arrays （FPGA） has been proposed.In the test approach,SBs （switch boxes） of IRs in FPGA has been utilized to test IRs.Furthermore,configurable logic blocks （CLBs） in FPGA have also been employed to enhance driving capability and the position of fault IR can be determined by monitoring the IRs associated SBs.As a result,IRs can be scanned maximally with minimum configuration patterns.In the experiment,an in-house developed FPGA test system based on system-on-chip （SoC） hardware/software verification technology has been applied to test XC4000E family of Xilinx.The experiment results revealed that the IRs in FPGA can be tested by 6 test patterns.
基金Supported by the National Natural Science Foundation of China(No.11971433)the First Class Discipline of Zhejiang-A(Zhejiang Gongshang University-Statistics)the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
文摘In this paper,we consider testing the hypothesis concerning the means of two independent semicontinuous distributions whose observations are zero-inflated,characterized by a sizable number of zeros and positive observations from a continuous distribution.The continuous parts of the two semicontinuous distributions are assumed to follow a density ratio model.A new two-part test is developed for this kind of data.The proposed test takes the sum of one test for equality of proportions of zero values and one conditional test for the continuous distribution.The test is proved to follow a 2 distribution with two degrees of freedom.Simulation studies show that the proposed test controls the type I error rates at the desired level,and is competitive to,and most of the time more powerful than two popular tests.A real data example from a dietary intervention study is used to illustrate the usefulness of the proposed test.
文摘Background: We aim to determine the proportions and patterns of resistance to first-line drugs: isoniazid (H), rifampicin (R), ethambutol (E) and streptomycin (S) among pulmonary tuberculosis patients. Methods: Strains were obtained from 1584 culture positive pulmonary tuberculosis patients. All specimens were inoculated into L?wenstein-Jensen media (LJ) and TK selective;drug susceptibility tests (DST) were performed for first-line drugs. Results: Multidrug resistant (MDR) were detected in 146 (9.2%) isolates. Three hundred (18.9%) isolates were resistant to H;220 (13.9%) to R;168 (10.6%) to S;137 (8.6%) to E. Any drug resistance was detected in 442 (27.9%) isolates. MDR rate was higher in male patients than females (P = 0.006). MDR rates were different according to the age groups (P = 0.02). The highest rate was in 35 - 44 years and the lowest rate was in 15 - 24 years. Conclusions: We found an association between middle age and male gender and MDR tuberculosis.
文摘Background: Tuberculosis (TB) is an infectious disease caused by the bacillus Mycobacterium tuberculosis. Anti-tuberculosis drug resistance is an emerging health problem in Kenya and especially in Coastal region. This is a major challenge in tuberculosis control. Diagnosis is based on Ziel-Neelsen staining alone and patients are treated without information on sensitivity patterns. Aim: This study aimed to determine drug susceptibility patterns of Mycobacterium tuberculosis in Coastal Kenya. Study Design: Hospital and laboratory based cross-sectional study was carried between April 2015 and July 2016 at Coast General Referral hospital;Tudor, Port-Reitz, Likoni Sub-County hospitals;Mlaleo, Kongowea and Mikindani health centers. Methodology: Sputum samples from patients with bacteriological confirmed TB on microscopy were cultured on Lowenstein Jensen (LJ) media. Strains of MTB complex from Lowenstein Jensen (LJ) slopes were subjected to drug susceptibility testing (DST) to first-line drugs including isoniazid (H), rifampicin (R), streptomycin (S) and Ethambutol (E) using proportional method on the Mycobacterium Growth Indicator Tube (MGIT) conventional method. Participants were offered diagnostic testing and counselling for HIV testing. Results: Drug sensitivity test was performed for a total of 210 Mycobacterium tuberculosis isolates for the first line anti-TB drugs. About seventy eight percent and twenty nine percent of the strains from new patients and previously treated patients were fully sensitive to all the drugs tested respectively. Prevalence of any resistance to one drug was 102 (48.6%, 95% CI: 20.45 - 28.23). Any single drug resistance was most frequent in isoniazid 30 (16.0%), Ethambutol 20 (10.0%), Streptomycin 18 (18.3%) and Rifampicin 4 (2.1%) in newly diagnosed patients. Among previously treated patients any resistance to streptomycin, ethambutol, isoniaziad and rifampicin was 10 (58.8%), 9 (52.9%), 7 (41.2%) and 4 (23.5%) respectively. Prevalence of MDR-TB defined as resistant to at least both isoniazid and rifampicin was 10 (4.8%) among new and previously treated patients respectively. Conclusion: The current study reveals that the overall resistance to first line anti-TB drugs was high. Although the rate of MDR-TB was relatively low, this signifies that conditions favouring the spread of MDR-TB are on high rise. Therefore, it is essential to address the problems of development of drug re-sistant strains of TB by establishing good TB programmes (DOTS). Patients’ adherence to anti-TB drugs and introducing drug sensitivity testing (DST) services at County level hospitals will minimize occurrence of drug resistant.
文摘DDR3芯片是一种能最高支持1600 Mbps传输速率的高速存储器芯片,本文对该类芯片的功能描述,寄存器配置进行介绍,针对ATE(Automated Test Equipment,自动测试设备)测试机台设计了相应的硬件Loadboard,最后在ATE测试机台上进行了速度等级测试,测试结果验证了DDR3芯片在最高频率1600Mbps下的功能正确性,运用shmoo进行绘制眼图,分析DDR3的信号完整性,为DDR3芯片测试提供了一定的参考。
基金Sponsored by the National Natural Science Fund(41801064,71790611)China Postdoctoral Science Foundation(2019 T120114,2019M650756)the Central Asian Atmospheric Science Research Fund(CAAS201804)
文摘In this study, based on the data on the frequency of waterlogging events and the number of waterlogging days of 1,638 stations from 1961 to 2016, a variety of mathematical statistics methods were used to analyze the spatiotemporal evolution of waterlogging events in eastern China. The results showed that:① In terms of time, the annual frequency of waterlogging events and the number of waterlogging days in eastern China in 1961–2016 showed an increasing trend despite of fluctuations. In the interdecadal changes, the highest frequency of waterlogging events and the greatest number of waterlogging days occurred in the 1990s, and from the 1960s to the 1980s, the frequency of waterlogging events and the number of waterlogging days in eastern China showed a decreasing trend. There were 6-year and 30-year periodic variations in the frequency of waterlogging events and the number of waterlogging days in eastern China, and mutations occurred in 1991.② In terms of space, from 1961 to 2016, the areas with high frequency of waterlogging events in various years in eastern China were mainly South China, western and southern Yunnan, northern Jiangsu, southern Zhejiang, northern Fujian, junction areas between Hunan and Chongqing, northern Sichuan, and eastern Liaoning.③ In the spatial distribution of change trends and fluctuation characteristics, the frequency of waterlogging events and the number of waterlogging days in eastern China increased significantly in the southeastern coastal areas from 1961 to 2016, and the fluctuations of the frequency of waterlogging events and the number of waterlogging days in eastern China from 1961 to 2016 presented a spatial variation pattern of low in the southwest and high in the northwest.
基金Supported by the National Key Research and Development Program of China(Grant Number 2021YFC2301000)the Capital's Funds for Health Improvement and Research(No.2024-2G-7106).
文摘Introduction:This study aimed to characterize the genetic diversity and antimicrobial resistance patterns of Campylobacter isolates collected throughout China from 2020 to 2023.Methods:Campylobacter isolates analyzed in this study were obtained from the National Pathogen Identification Network Center database,maintained by the National Institute for Infectious Disease Control and Prevention of the Chinese Center for Disease Control and Prevention.Antimicrobial susceptibility testing(AST)was performedagainsteleven antimicrobial agents.Genomic characteristics were analyzed through comprehensive genome sequence analysis.Results:Between 2020 and 2023,the National Pathogen Identification Network documented 1,077 Campylobacter jejuni(C.jejuni)and 221 Campylobacter coli(C.coli)isolates.Most isolates originated from patients presenting with diarrhea.Antimicrobial susceptibility testing was conducted on 634 C.jejuni and165C.coli isolates.The tested isolates demonstrated high resistance rates to nalidixic acid(78.22%),ciprofloxacin(78.07%),and tetracycline(71.96%).Longitudinal analysis of antimicrobial susceptibility testing results revealed a declining resistance trend from 2020 to 2023.Whole genome sequences were obtained for 540 C.jejuni and 125 C.coli isolates within the database.Virulence factors and antibiotic resistance determinants were identified using the VFDB and CARD databases,respectively.Phylogenetic relationships were established through Snippy 4.0 software analysis based on core genome comparisons.Conclusions:This comprehensive analysis.describes the antibiotic resistance profiles and genetic characteristics of Campylobacter isolates collected through the Identification Network Database from 2020 to 2023,establishing a foundational framework for campylobacteriosis control and prevention strategies in China.
文摘A leading position in the areas of testing,instrumentation and machine control has been established by members of the British Textile Machinery Association(BTMA)and a number of new developments in these fields will be showcased at this year’s ITMA Asia+CITME exhibition,which takes place in Singapore from October 28-31.“Many of our members are currently developing new technologies,either in-house or increasingly through joint projects,and there will be much to reveal by the time of ITMA Asia in Singapore,”says BTMA CEO Jason Kent.“Some of the most recent developments are really going beyond what has previously been possible.”
文摘Advancements in semiconductor technology are making gate-level test generation more challenging. This is because a large amount of detailed structural information must be processed in the search process of automatic test pattern generation (ATPG). In addition, ATPG needs to deal with new defects caused by process variation when IC is shrinking. To reduce the computation effort of ATPG, test generation could be started earlier at higher abstraction level, which is in line with top-down design methodology that has become more popular nowadays. In this research, we employ Chen’s high-level fault model in the high-level ATPG. Besides shorter ATPG time as shown in many previous works, our study showed that high-level ATPG also contributes to test compaction. This is because most of the high-level faults correlate with the gate-level collapsed faults especially at input/output of the modules in a circuit. The high-level ATPG prototype used in our work is mainly composed by constraint-driven test generation engine and fault simulation engine. Experimental result showed that more reduced/compact test set can be generated from the high-level ATPG.
基金supported by the National Key Program for Developing Basic Sciences under Grant 2012CB417202the National Natural Science Foundation of China under Grant No. 41175038, No. 41305088 and No. 41075023+4 种基金the Meteorological Special Project "Radar network observation technology and QC"the CMA Key project "Radar Operational Software Engineering"the Chinese Academy of Meteorological Sciences Basic ScientificOperational Projects "Observation and retrieval methods of micro-physics and dynamic parameters of cloud and precipitation with multi-wavelength Remote Sensing"Project of the State Key Laboratory of Severe Weather grant 2012LASW-B04
文摘A variety of faulty radar echoes may cause serious problems with radar data applications,especially radar data assimilation and quantitative precipitation estimates.In this study,＂test pattern＂ caused by test signal or radar hardware failures in CINRAD （China New Generation Weather Radar） SA and SB radar operational observations are investigated.In order to distinguish the test pattern from other types of radar echoes,such as precipitation,clear air and other non-meteorological echoes,five feature parameters including the effective reflectivity data percentage （Rz）,velocity RF （range folding） data percentage （RRF）,missing velocity data percentage （RM）,averaged along-azimuth reflectivity fluctuation （RNr,z） and averaged along-beam reflectivity fluctuation （RNa,z） are proposed.Based on the fuzzy logic method,a test pattern identification algorithm is developed,and the statistical results from all the different kinds of radar echoes indicate the performance of the algorithm.Analysis of two typical cases with heavy precipitation echoes located inside the test pattern are performed.The statistical results show that the test pattern identification algorithm performs well,since the test pattern is recognized in most cases.Besides,the algorithm can effectively remove the test pattern signal and retain strong precipitation echoes in heavy rainfall events.
文摘Kissing bonds are defects in the adhesive bonds with intimate contact of touching surface but considerably lowered shear strength. Their detection specifically in the aerospace area is so not satisfactory. Usually, kissing bonds are inconspicuous in ultrasonic C-scans. However, the determination of attributes in the time domain and the frequency domain of an ultrasound signal provides the opportunity to derive a pattern for bonded area. Deviations from the pattern found in inconspicuous bonding areas indicate kissing bonds. The survey described here deals with the manufacturing of adhesively joint samples that purposefully include kissing bonds, as well as potential solutions for detecting them through ultrasonic testing combined with pattern recognition. The properties of the epoxy-based adhesive were varied by changing the mixing ratios between resin and hardener. Samples with a mixing ratio far apart from the manufacturer’s recommendation with an inconspicuous appearance in a C-scan, but low shear strength values were taken for further evaluation. After a definition and learning phase, a 100 percent hit rate to separate good bondings from kissing bonds could be derived in a blind test. The discriminating feature found is due to the frequency shift between good and kissing bonds as well as the relative amplitude of the second peak.
基金Supported by Joint Research Fund for Overseas Chinese Young Scholars (No. 50128503) and National Natural Science Foundation of China (No. 50390060)
文摘This paper presents modeling tools based on Boolean satisfiability (SAT) to solve problems of test generation for combinational circuits. It exploits an added layer to maintain circuit-related information and value justification relations to a generic SAT algorithm. It dovetails binary decision graphs (BDD) and SAT techniques to improve the efficiency of automatic test pattern generation (ATPG). More specifically, it first exploits inexpensive reconvergent fanout analysis of circuit to gather information on the local signal correlation by using BDD learning, then uses the above learned information to restrict and focus the overall search space of SAT-based ATPG. Its learning technique is effective and lightweight. The experimental results demonstrate the effectiveness of the approach.
基金SINOPEC's Scientific and Technological Research Project:Research on effective production strategies of Jurassic continental shale oil and gas(No.P21078-5).
文摘Pressure buildup testing can be used to analyze fracture network characteristics and conduct quantitative interpretation of relevant parameters for shale gas wells,thus providing bases for assessing the well productivity and formulating proper development strategies.This study establishes a new well test interpretation model for fractured horizontal wells based on seepage mechanisms of shale reservoirs and proposes a method for identifying fracturing patterns based on the characteristic slopes of pressure buildup curves and curve combination patterns.The pressure buildup curve patterns are identified to represent three types of shale reservoirs in the Sichuan Basin,namely the moderately deep shale reservoirs with high pressure,deep shale reservoirs with ultra-high pressure,and moderately deep shale reservoirs with normal pressure.Based on this,the relationship between the typical pressure buildup curve patterns and the fracture network types are put forward.Fracturing effects of three types of shale gas reservoir are compared and analyzed.The results show that typical flow patterns of shale reservoirs include bilinear flow in primary and secondary fractures,linear flow in secondary fractures,bilinear flow in secondary fractures and matrix,and linear flow in matrix.The fracture network characteristics can be determined using the characteristic slopes of pressure buildup curves and curve combinations.The linear flow in early secondary fractures is increasingly distinct with an increase in primary fracture conductivity.Moreover,the bilinear flow in secondary fractures and matrix and the subsequent linear flow in the matrix occur as the propping and density of secondary fractures increase.The increase in the burial depth,in-situ stress,and stress difference corresponds to a decrease in the propping of primary fractures that expand along different directions in the shale gas wells in the Sichuan Basin.Four pressure buildup curve patterns exist in the Sichuan Basin and its periphery.The pattern of pressure buildup curves of shale reservoirs in the Yongchuan area can be described as 1/2/→1/4,indicating limited stimulated reservoir volume,poorly propped secondary fractures,and the forming of primary fractures that extend only to certain directions.The pressure buildup curves of shale reservoirs in the main block of the Fuling area show a pattern of 1/4/→1/2 or 1/2,indicating greater stimulated reservoir volume,well propped secondary fractures,and the forming of complex fracture networks.The pattern of pressure buildup curves of shale reservoirs in the Pingqiao area is 1/2/→1/4→/1/2,indicating a fracturing effect somewhere between that of the Fuling and Yongchuan areas.For reservoirs with normal pressure,it is difficult to determine fracture network characteristics from pressure buildup curves due to insufficient formation energy and limited liquid drainage.
