期刊文献+
共找到5,195篇文章
< 1 2 250 >
每页显示 20 50 100
Effect of FeSi additive in dual-chamber sample cup on thermal analysis characteristic values and vermiculating rate of compacted graphite iron
1
作者 De-quan Shi Ze-yu Liu +1 位作者 Gui-li Gao Yi-cheng Feng 《China Foundry》 SCIE EI CAS CSCD 2024年第1期91-100,共10页
Thermal analysis plays a key role in the online inspection of molten iron quality.Different solidification process of molten iron can be reflected by thermal analysis curves,and silicon is one of important elements af... Thermal analysis plays a key role in the online inspection of molten iron quality.Different solidification process of molten iron can be reflected by thermal analysis curves,and silicon is one of important elements affecting the solidification of molten iron.In this study,FeSi75 was added in one chamber of the dual-chamber sample cup,and the influences of FeSi75 additive on the characteristic values of thermal analysis curves and vermiculating rate were investigated.The results show that with the increase of FeSi75,the start temperature of austenite formation TALfirstly decreases and then increases,but the start temperature of eutectic growth TSEF,the lowest eutectic temperature TEU,temperature at maximum eutectic reaction rate TEM,and highest eutectic temperature TERkeep always an increase.The temperature at final solidification point TEShas little change.The FeSi75 additive has different influences on the vermiculating rate of molten iron with different vermiculation,and the vermiculating rate increases for lower vermiculation molten iron while decreases for higher one.According to the thermal analysis curves obtained by a dual-chamber sample cup with 0.30wt.%FeSi75 additive in one chamber,the vermiculating rate of molten iron can be evaluated by comparing the characteristic values of these curves.The time differenceΔtERcorresponding to the highest eutectic temperature TERhas a closer relationship with the vermiculating rate,and a parabolic regression curve between the time differenceΔtERand vermiculating rateηhas been obtained within the range of 65%to 95%,which is suitable for the qualified melt. 展开更多
关键词 FeSi75 additive characteristic value vermiculating rate thermal analysis compacted graphite iron
下载PDF
The Convergence Rate of Fréchet Distribution under the Second-Order Regular Variation Condition
2
作者 Xilai Dai 《Journal of Applied Mathematics and Physics》 2024年第5期1597-1605,共9页
In this article we consider the asymptotic behavior of extreme distribution with the extreme value index γ>0 . The rates of uniform convergence for Fréchet distribution are constructed under the second-order ... In this article we consider the asymptotic behavior of extreme distribution with the extreme value index γ>0 . The rates of uniform convergence for Fréchet distribution are constructed under the second-order regular variation condition. 展开更多
关键词 Convergence rate Second-Order Regular Variation Condition Fréchet Distribution Extreme value Index
下载PDF
Analysis of the USD/JPY and EUR/JPY Exchange Rates Using Multifractal Analysis and Extreme Value Theory
3
作者 Fumio Maruyama 《Journal of Applied Mathematics and Physics》 2023年第10期2816-2827,共12页
We performed a multifractal analysis using wavelet transform to detect the changes in the fractality of the USD/JPY and EUR/JPY exchange rates, and predicted their extreme values using extreme value theory. After the ... We performed a multifractal analysis using wavelet transform to detect the changes in the fractality of the USD/JPY and EUR/JPY exchange rates, and predicted their extreme values using extreme value theory. After the 1997 Asian financial crisis, the USD/JPY and EUR/JPY became multifractal, then the USD/JPY became monofractal and stable, and yen depreciation was observed. However, the EUR/JPY became multifractal and unstable, and a strong yen depreciation was observed. The coherence between the USD/JPY and EUR/JPY was strong between 1995 and 2000. After the 2007-2008 financial crisis, the USD/JPY became monofractal and stable, and yen appreciation was observed. However, the EUR/JPY became multifractal and unstable, and strong yen appreciation was observed. Various diagnostic plots for assessing the accuracy of the GP model fitted to USD/JPY and EUR/JPY are shown, and all the diagnostic plots support the fitted GP model. The shape parameters of USD/JPY and EUR/JPY were close to zero, therefore the USD/JPY and EUR/JPY did not have finite upper limits. We predicted the maximum return level for the return periods of 10, 20, 50, 100, 350, and 500 years and their respective 95% confidence intervals (CI). As a result, the 10-year and 100-year return levels for USD/JPY were estimated to be 149.6 and 164.8, with 95% CI [143.2, 156.0] and [149.4, 180.1], respectively. 展开更多
关键词 WAVELET MULTIFRACTAL Extreme value theory GP USD/JPY and EUR/JPY Ex-change rates
下载PDF
Sustainability Assessment of Banana (Musa spp.) Yield Gap Reduction through Value Chain Development Interventions in Smallholder Farming Systems in Manicaland, Zimbabwe
4
作者 Mthintwa Tawanda Hove Hlamalani Ngwenya Johan Van Niekerk 《Agricultural Sciences》 2024年第8期962-992,共31页
This study evaluated the effectiveness of donor supported agricultural value chain development projects in sustainably narrowing yield gaps for banana smallholder farmer producers in Manicaland, Zimbabwe. The study us... This study evaluated the effectiveness of donor supported agricultural value chain development projects in sustainably narrowing yield gaps for banana smallholder farmer producers in Manicaland, Zimbabwe. The study used a mixed methods research design that relied on farmers records for the quantitative analysis and focus group discussion and in-depth interviews for key experts for the qualitative aspects. A mix of regression analysis, t-tests, Pearsons’s correlation and analysis of variance statistical methods were used for the quantitative analysis while thematic response analysis was used for the qualitative engagements. The findings showed that by the end of the activity, the project had successfully narrowed the banana yield gaps to 18.66 tons per hectare working with a potential yield base of 40 tons. However, 5 years after the project closure the yield gap had fallen to 24.7 tons indicating a lack of sustainability of yield gap reduction. However, the yield gap slump does not override the fact that farmers on average were still able to sell approximately 5 tons per every 6 months after 5 years from the project closure which is beyond any poverty threshold. This suggests genuine upward economic mobility. Additionally, in analyzing what factors had the greatest influence on yield gap reduction, the access to fertilizer ranked highest where genetics, irrigation and improved agronomy followed in that respective order. The study further showed that farmers who receive value chain development support whilst at an already commercialized state tend to maintain productivity thresholds higher in comparison to those who are at a pre commercial state. This is evidenced by the fact that the pre commercial farmers had a yield reduction of 30.83 percent after 5 years of the project closure whereas the former realized a productivity growth of 7.84%. In conclusion, whilst the intervention was successful in transitioning farmers out of poverty, more investment should be made towards transitioning smallholder farmers to integrated soil fertility management practices and improvement of agronomic efficiency through stronger on field collaboration between research institutions, the government and development institutions. 展开更多
关键词 Yield Gap value Chain Development Soil Health Varietal Replacement rate Sustainability and Economic Mobility
下载PDF
Cyberattack Ramifications, The Hidden Cost of a Security Breach
5
作者 Meysam Tahmasebi 《Journal of Information Security》 2024年第2期87-105,共19页
In this in-depth exploration, I delve into the complex implications and costs of cybersecurity breaches. Venturing beyond just the immediate repercussions, the research unearths both the overt and concealed long-term ... In this in-depth exploration, I delve into the complex implications and costs of cybersecurity breaches. Venturing beyond just the immediate repercussions, the research unearths both the overt and concealed long-term consequences that businesses encounter. This study integrates findings from various research, including quantitative reports, drawing upon real-world incidents faced by both small and large enterprises. This investigation emphasizes the profound intangible costs, such as trade name devaluation and potential damage to brand reputation, which can persist long after the breach. By collating insights from industry experts and a myriad of research, the study provides a comprehensive perspective on the profound, multi-dimensional impacts of cybersecurity incidents. The overarching aim is to underscore the often-underestimated scope and depth of these breaches, emphasizing the entire timeline post-incident and the urgent need for fortified preventative and reactive measures in the digital domain. 展开更多
关键词 Artificial Intelligence (AI) Business Continuity Case Studies Copyright Cost-Benefit Analysis Credit Rating Cyberwarfare Cybersecurity Breaches Data Breaches Denial of Service (DOS) Devaluation of Trade Name Disaster Recovery Distributed Denial of Service (DDOS) Identity theft increased Cost to Raise Debt Insurance Premium Intellectual Property Operational Disruption Patent Post-Breach Customer Protection Recovery Point Objective (RPO) Recovery Time Objective (RTO) Regulatory Compliance Risk Assessment Service Level Agreement Stuxnet Trade Secret
下载PDF
ESTIMATION OF THE CRITICAL RATE OF TEMPERATURE INCREASE OF THERMAL EXPLOSION OF NITROCELLULOSE USING NON-ISOTHERMAL DSC 被引量:1
6
作者 胡荣祖 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2003年第3期285-290,共6页
A method of estimating the critical rate of temperature increase of thermal explosion for the first orderautocatalytic decomposition reaction system using non-isothermal DSC is presented. Information is obtained on th... A method of estimating the critical rate of temperature increase of thermal explosion for the first orderautocatalytic decomposition reaction system using non-isothermal DSC is presented. Information is obtained on theincreasing rate of temperature in nitrocellulose containing 13.54% of nitrogen when the first order autocatalytic decomposition converts into thermal explosion. 展开更多
关键词 DSC NITROCELLULOSE Increasing rate of temperature NON-ISOtheRMAL
下载PDF
Numerical Computing for a Class of Free Multipoint Boundary Value Problem of O.D.E in the Intervention of Exchange Rate
7
作者 赵连霞 朱正佑 秦成林 《Journal of Shanghai University(English Edition)》 CAS 2005年第4期320-325,共6页
In this paper by means of generalized shooting method and homotopy technique a numerical method was given for computing free multipoint boundary value problem proposed in the intervention of exchange rate by Cadenilla... In this paper by means of generalized shooting method and homotopy technique a numerical method was given for computing free multipoint boundary value problem proposed in the intervention of exchange rate by Cadenillas and Femaado Zapatero. A numerical example was given for illustrating the validity of this method. 展开更多
关键词 exchange rate interventon nonlinear ordinary differential equation free boundary value problem generalized shooting method
下载PDF
Is It Wrong to Apply the Intrinsic Rate of Natural Increase to Individuals and Compare It among Genotypes?
8
作者 Takahiro Miyo 《Open Journal of Genetics》 2018年第1期1-13,共13页
In order to gain insights into the seasonal dynamics of genetic variation in insecticide resistance within a natural population of Drosophila melanogaster during population growth, which we considered the most importa... In order to gain insights into the seasonal dynamics of genetic variation in insecticide resistance within a natural population of Drosophila melanogaster during population growth, which we considered the most important ecological factor there, we conducted a series of genetic analyses of resistance factors involved in that population and compared individual-based intrinsic rates of natural increase among resistance genotypes. However, some researchers have argued that it is a misconception to apply the intrinsic rate of natural increase to individuals, because it is a population parameter. We consider that their criticisms were incorrect. In this article, I described our research briefly and set forth the reasons why we conducted these studies. 展开更多
关键词 Drosophila MELANOGASTER INSECTICIDE Resistance Intrinsic rate of NATURAL increase NATURAL Population
下载PDF
Effect of Sudden Increase of Solid Feed Rate on the Arching in Hoppers Connected to a Moving-Bed Standpipe with Interstitial Gas Flow
9
作者 景山 李洪钟 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 1999年第1期1-9,共9页
In this paper, a model is proposed for the prediction of the width of arching in hoppers resulted from sudden changes in solid feed rates. Such changes in solid feed rate usually come from the collision on the surface... In this paper, a model is proposed for the prediction of the width of arching in hoppers resulted from sudden changes in solid feed rates. Such changes in solid feed rate usually come from the collision on the surface of the moving-bed in the standpipe. The model also takes into account the effect of the powder height in the standpipe of the hopper. The model proves to be adaptable for predicting operational conditions to avoid arching by keeping constant powder height in the main standpipe with interstitial gas flow. 展开更多
关键词 moving-bed standpipe width of arching model sudden increase of solid feed rate
下载PDF
Value of preoperative erythrocyte sedimentation rate, CRP and D-D levels in evaluating the prognosis of elderly patients after hip replacement
10
作者 Yong Yao Jian-Xin Yan Gang Wu 《Journal of Hainan Medical University》 2020年第1期61-61,共1页
Objective: To analyze the clinical value of blood sedimentation rate, C-reactive protein (CRP) and D-dimer (D-D) expression levels in elderly patients before hip replacement for judging the prognosis after operation. ... Objective: To analyze the clinical value of blood sedimentation rate, C-reactive protein (CRP) and D-dimer (D-D) expression levels in elderly patients before hip replacement for judging the prognosis after operation. Methods 88 patients who needed hip replacement in orthopaedic surgery of our hospital from January 2014 to December 2017 were selected as the research object. According to the prognosis of patients, they were divided into two groups. 42 patients with good prognosis were treated as observation group and 46 patients with poor prognosis were treated as control group. The ESR and CRP of the two groups were recorded and analyzed before and after operation. The expression level of D-D, perioperative changes, and the prognostic value of the area under the curve (AUC) were compared by drawing the patient's working characteristic curve (ROC curve). Results The expression levels of ESR, CRP and D-D in the observation group were significantly higher than those in the control group (P < 0.05). The expression levels of CRP in the observation group were significantly higher than those in the control group (P < 0.05). The expression levels of ESR and CRP in the observation group before discharge were significantly higher than those in the control group (P < 0.05). There was significant difference between the two groups (P < 0.05);the level of ESR expression before and 2 days after operation was significantly lower than that before discharge (P < 0.05);the level of ESR expression before operation was significantly lower than that 2 days after operation (P < 0.05);and the CRP and D-D table before operation were compared between the two groups (P < 0.05). The level of CRP and D-D expression in two groups was significantly higher than that before discharge (P < 0.05). In this study, two groups of patients were infected. The incidence of thrombosis in the observation group was higher than that in the control group, but the difference was not statistically significant (P > 0.05). The Harris score of the observation group was significantly higher than that of the control group (P < 0.05). Conclusion There are abnormal levels of ESR, CRP and D-D expression in elderly patients with hip replacement before operation, and they have certain clinical value in evaluating the prognosis of elderly patients after hip replacement. 展开更多
关键词 ERYTHROCYTE SEDIMENTATION rate C-reactive protein D-DIMER HIP replacement predictive value
下载PDF
A Probe into the Mortgage Rates of Land Contract Management Rights Based on Unified Annual Output Value 被引量:1
11
作者 Zhongjun YI 《Asian Agricultural Research》 2013年第9期49-52,共4页
The mortgage of land contract management rights has launched a pilot project in Ningxia,Hubei,Henan,Guizhou,Chongqing and other provinces,municipalities and autonomous regions,which provides a good solution to the pro... The mortgage of land contract management rights has launched a pilot project in Ningxia,Hubei,Henan,Guizhou,Chongqing and other provinces,municipalities and autonomous regions,which provides a good solution to the problem of funds for rural development and plays a huge role in promoting local rural economic development.In the mortgage financing of land contract management rights implemented in various regions,how to determine a scientific,accurate and reasonable mortgage rate of land contract management rights becomes a difficulty troubling the mortgage financing of land.On the basis of unified annual output value of land,this article uses survey method,income capitalization method,and comparison method to analyze the value of land contract management rights,and finally determine the mortgage rates of land contract management rights. 展开更多
关键词 Land CONTRACT management RIGHTS MORTGAGE rates UNI
下载PDF
Loss Rate Estimation of Yield and Output Value of Tobacco Leaf Infected by Tobacco Blown Spot (Alternaria alternata) 被引量:3
12
作者 余清 《Plant Diseases and Pests》 CAS 2010年第6期23-27,63,共6页
[Objective] The paper was to study the effect of tobacco blown spot on the yield and output value of tobacco leaf.[Method]The upper,middle and lower leaves in tobacco plant were selected during the harvest period of t... [Objective] The paper was to study the effect of tobacco blown spot on the yield and output value of tobacco leaf.[Method]The upper,middle and lower leaves in tobacco plant were selected during the harvest period of tobacco to carry out loss rate estimation of yield and output value of tobacco leaf caused by different disease levels of brown spot.Regression correlation analysis was also conducted.[Result]The disease levels of brown spot had extremely significant strong negative correlation with single leaf weight of tobacco leaf,and it had extremely significant strong positive correlation with the loss rate of single leaf weight.The increase speed of loss rate of single leaf weight of middle and upper leaves was obviously faster than that of lower leaves.The loss rates of single leaf weight of upper,middle and lower leaves were 3.18%-28.95%,3.43%-28.88% and 10.07%-26.90%,respectively.The higher the disease level of blown spot was,the lower the yield and output value of tobacco leaf was,and the corresponding loss rate was also higher.Correlation analysis showed that the disease level of blown spot had extremely significant strong negative correlation with the yield and output value of tobacco leaf,and it had extremely significant strong positive correlation with the loss rate of yield and output value.The negative impact of blown spot on the output value of tobacco leaf was far greater than that on the yield.The highest loss rate of the yield of tobacco leaf was 28.56%,while the highest loss rate of output value reached 89.67%.[Conclusion] The study provided theoretical basis for accurately holding the critical period for the control of blown spot,thus reducing the damage on tobacco leaf and improving the output value of tobacco leaf. 展开更多
关键词 Tobacco brown spot Single-leaf weight Yield of tobacco leaf Output value of tobacco leaf Loss rate estimation
下载PDF
Dynamic behaviors of water-saturated and frozen sandstone subjected to freeze-thaw cycles 被引量:3
13
作者 Feng Gao Cong Li +2 位作者 Xin Xiong Yanan Zhang Keping Zhou 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第6期1476-1490,共15页
In high-altitude cold areas,freeze-thaw(F-T)cycles induced by day-night and seasonal temperature changes cause numerous rock mass slope engineering disasters.To investigate the dynamic properties of rock in the natura... In high-altitude cold areas,freeze-thaw(F-T)cycles induced by day-night and seasonal temperature changes cause numerous rock mass slope engineering disasters.To investigate the dynamic properties of rock in the natural environment of a high-altitude cold area,standard specimens were drilled from the slope of the Jiama copper mine in Tibet,and dynamic compression tests were performed on watersaturated and frozen sandstone with different numbers of F-T cycles(0,10,20,30,and 40)by the split Hopkinson pressure bar(SHPB)system with a cryogenic control system.The influence of water-saturated and frozen conditions on the dynamic performance of sandstone was investigated.The following conclusions are drawn:(1)With increasing strain rate,the attenuation factor(la)of water-saturated sandstone and the intensifying factor(li)of frozen sandstone linearly increase.As the number of F-T cycles increases,the dependence factor(ld)of water-saturated sandstone linearly decreases,whereas the ld of frozen sandstone linearly increases.(2)The prediction equation of the dynamic compressive strength of water-saturated and frozen sandstone is obtained,which can be used to predict the dynamic compressive strength of sandstone after various F-T cycles based on the strain rate.(3)The mesoscopic mechanism of water-saturated and frozen sandstone’s dynamic compressive strength evolution is investigated.The water softening effect causes the dynamic compressive strength of water-saturated sandstone to decrease,whereas the strengthening effect of pore ice causes it to increase.(4)The decrease in the relative dynamic compressive strength of water-saturated sandstone and the increase in the relative dynamic compressive strength of frozen sandstone can be attributed to the increased porosity. 展开更多
关键词 Freeze-thaw(F-T)cycle damage Dynamic properties Split Hopkinson pressure bar(SHPB) Increasing rate of porosity
下载PDF
APPLICATION OF WYATT-WHITE METHOD TO CALCULATING INTRINSIC RATES OF INCREASE FOR HYMENOPTEROUS PARASITOIDS
14
作者 况荣平 Sandy M.Smith 《Zoological Research》 CAS CSCD 1993年第3期208-214,共7页
The method developed by Wyatt and White (1977) was applied to calculate the intrinsic rates of increase for parasitoids based on 23 fecundity data sets from the literature. The studies showed that there existed the li... The method developed by Wyatt and White (1977) was applied to calculate the intrinsic rates of increase for parasitoids based on 23 fecundity data sets from the literature. The studies showed that there existed the linear relationship between the accurate values of rm and In f (Md) / d or In (A/d/2) / d, that is, 1) rm= 0.845 In (Md) / d or 2) rm= 0.880 In (Md/ 2) / d. Where d is the prereproductive time, Md is the number of female offspring produced per original female from the first to the dthday of reproduction, and Md/2 is the number of female offspring produced per original female from the first to the (d/ 2) th day of reproduction. These equations can provide the accurate estimates of rm for parasitoids in this study. The approach is advantageous because it does not require the construction of detailed fecundity tables for estimating parasitoid rates of increase. Of course, whether these equations are appropriate for the other taxa will need to be further studied. 展开更多
关键词 PARASITOID Intrinsic rate of increase Calculation
下载PDF
Combined APACH Ⅱ score and arterial blood lactate clearance rate to predict the prognosis of ARDS patients 被引量:21
15
作者 Wen-Hui Wu Yuan-Yuan Niu +4 位作者 Chang-Ran Zhang Long-Bin Xiao Hui-Shao Ye De-Mao Pan Mian Zeng 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2012年第8期656-660,共5页
Objective:To explore the easily applicable indicators of practical value to evaluate the prognosis of acute respiratory distress syndrome(ARDS).Methods:Blood and biochemical tests and bloodgas analyses were performe... Objective:To explore the easily applicable indicators of practical value to evaluate the prognosis of acute respiratory distress syndrome(ARDS).Methods:Blood and biochemical tests and bloodgas analyses were performed upon entry into the ICUs,12 h,24 h,48 h and 72 h after that in 72 ARDS patients(who were admitted to the ICUs of our hospital from January 2000 to December 2009).Then APACHEⅡscores were achieved by combining relevant physiological parameters and laboratory results.Results:There was a statistical difference between the death group and survival group at different time points upon entering the ICUs in terms of APACHEⅡscore, alveolar-arterial oxygen difference and arterial blood lactate clearance rate.PaO<sub>2</sub>/FiO<sub>2</sub> values were recorded to be statistically different between the death group and survival group 24 h,48 h and 72 h,respectively after entry into the ICUs.In addition,registered linear regression existed between APACHEⅡscore,alveolar-arterial oxygen difference or PaO<sub>2</sub>/FiO<sub>2</sub> value and time. APACHEⅡscore 24 h and 72 h after entering ICUs predicted mortality with an area under the ROC curve(AUC) standing respectively at 0.919 and 0.9SS.Arterial blood lactate clearance rate 12 h, 24 h,48 h and 72 h after entering ICUs predicted mortality with an area under the ROC curve (AUC) at 0.918,0.918,0.909 and 0.991,respectively.Conclusions:APACHEⅡscore applied in combination with arterial blood lactate clearance rate is of clinical significance in assessing the prognosis of ARDS patients. 展开更多
关键词 Acute respiratory distress syndrome APACHE Ⅱscore Arterial blood LACTATE clearance rate PaO2/FiO2 value Alveolar-arterial oxygen difference
下载PDF
Analysis of heart rate variability based on singular value decomposition entropy 被引量:2
16
作者 李世阳 杨明 +1 位作者 李存岑 蔡萍 《Journal of Shanghai University(English Edition)》 CAS 2008年第5期433-437,共5页
Assessing the dynamics of heart rate fluctuations can provide valuable information about heart status. In this study, regularity of heart rate variability (HRV) of heart failure patients and healthy persons using th... Assessing the dynamics of heart rate fluctuations can provide valuable information about heart status. In this study, regularity of heart rate variability (HRV) of heart failure patients and healthy persons using the concept of singular value decomposition entropy (SvdEn) is analyzed. SvdEn is calculated from the time series using normalized singular values. The advantage of this method is its simplicity and fast computation. It enables analysis of very short and non-stationary data sets. The results show that SvdEn of patients with congestive heart failure (CHF) shows a low value (SvdEn: 0.056±0.006, p 〈 0.01) which can be completely separated from healthy subjects. In addition, differences of SvdEn values between day and night are found for the healthy groups. SvdEn decreases with age. The lower the SvdEn values, the higher the risk of heart disease. Moreover, SvdEn is associated with the energy of heart rhythm. The results show that using SvdEn for discriminating HRV in different physiological states for clinical applications is feasible and simple. 展开更多
关键词 heart rate variability (HRV) singular value decomposition (SVD) ENTROPY congestive heart failure (CHF)
下载PDF
The Effect of a High-Frequency-Hearing-Threshold Weighted Value on the Diagnosis of Occupational-Noise-Induced Deafness 被引量:1
17
作者 Laijun Xue Yanhong Zhang Aichu Yang 《Journal of Biosciences and Medicines》 2018年第12期88-99,共12页
Objective: In order to provide a theoretical basis for the revision of the current diagnostic criteria for occupational noise-induced deafness (ONID), we evaluated the degree of ONID by analyzing different high-freque... Objective: In order to provide a theoretical basis for the revision of the current diagnostic criteria for occupational noise-induced deafness (ONID), we evaluated the degree of ONID by analyzing different high-frequency-hearing- threshold-weighted values (HFTWVs). Methods: A retrospective study was conducted to evaluate the diagnosis of patients with ONID from January 2016 to January 2017 in Guangdong province, China. Based on 3 hearing tests (each interval between the tests was greater than 3 days), the minimum threshold value of each frequency was obtained using the 2007 edition’s diagnostic criteria for ONID. The speech frequency and the HFTWVs were analyzed based on age, noise exposure, and diagnostic classi-fication using SPSS21.0. Results: 168 patients in total were involved in this study, 154 males and 14 females, and the average age was 41.18 ± 6.07. The diagnosis rate was increased by the weighted value of the high frequencies and was more than the mean value of the pure speech frequency (MVPSF). The diagnosis rate for the weighted 4 kHz frequency level increased by 13.69% (χ2 = 9.880, P = 0.002), the weighted 6 kHz level increased by 15.47% (χ2 = 9.985, P = 0.002), and the weighted 4 kHz + 6 kHz level increased by 15.47% (χ2 = 9.985, P = 0.002). The differences were all statistically significant. The diagnostic rate of the different thresholds showed no obvious difference between the genders. The age groups were divided into less than or equal to 40 years old (group A) and 40 - 50 years old (group B). There were several groups with a high frequency: high frequency weighted 4 kHz ( group A χ2 = 3.380, P = 0.050;group B χ2 = 4.054, P = 0.032), high frequency weighted 6 kHz (group A χ2 = 6.362, P = 0.012;group B χ2 = 4.054, P = 0.032), weighted 4 kHz + 6 kHz (group A χ2 = 6.362 P = 0.012;B χ2 = 4.054, P = 0.032) than those of MVPSF in the same group on ONID diagnosis rate. The differences between the groups were statistically significant. There was no significant difference between the age groups (χ2 = 2.265, P = 0.944). The better ear’s (the smaller hearing threshold weighted value) MVPSF and the weighted values for the different high frequencies were examined in light of the number of working years;the group that was exposed to noise for more than 10 years had significantly higher values than those of the average thresholds of each frequency band in the groups with 3 - 5 years of exposure (F = 2.271, P = 0.001) and 6 - 10 years of exposure (F = 1.563, P = 0.046). The differences were statistically significant. The different HFTWVs were higher than those of the MVPSF values, and the high frequency weighted 4 kHz + 6 kHz level showed the greatest difference, with an average increase of 2.83 dB. The diagnostic rate that included the weighted high frequency values was higher for the mild, moderate, and severe cases than those patients who were only screened with the pure frequency tests. The results of the comparisons of the diagnosis rates for mild ONID were as follows: the weighted 3 kHz high frequency level (χ2 = 3.117, P = 0.077) had no significant difference, but the weighted 4 kHz level (χ2 = 10.835, P = 0.001), 6 kHz level (χ2 = 9.985, P = 0.002), 3 kHz + 4 kHz level (χ2 = 6.315, P = 0.012), 3 kHz + 6 kHz level (χ2 = 6.315, P = 0.012), 4 kHz + 6 kHz level (χ2 = 9.985, P = 0.002), and 3 kHz + 4 kHz + 6 kHz level (χ2 = 7.667, P = 0.002) were significantly higher than the diagnosis rate of the mean value of the PSF. There was no significant difference between the 2 groups for the moderate and severe grades (P > 0.05). Conclusion: Different HFTWVs increase the diagnostic rate of ONID. The weighted 4 kHz, 6 kHz, and 4 kHz + 6 kHz high frequency values greatly affected the diagnostic results, and the weighted 4 kHz + 6 kHz high frequency hearing threshold value has the maximum the effect on the ONID diagnosis results. 展开更多
关键词 Noise OCCUPATIONAL Noise DEAFNESS NOISE-INDUCED HEARING Loss High Fre-quency HEARING THRESHOLD WEIGHTED value Diagnostic rate
下载PDF
pH Value Effects in Shear Rheology of Concentrated Alumina Suspensions 被引量:1
18
作者 曾人杰 魏光 B.Rand 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2000年第2期180-183,共4页
The influence of pH on the rheological properties of concentrated alumina suspensions was investigated. At various pH values, the alumina exhibited pseudoplastic, near Bingham flow behaviors. The fully-deflocculated s... The influence of pH on the rheological properties of concentrated alumina suspensions was investigated. At various pH values, the alumina exhibited pseudoplastic, near Bingham flow behaviors. The fully-deflocculated suspensions exhibited Newtonian flow behaviors, while the fully-flocculated suspensions demonstrated very high viscosity and shear yield stress. 展开更多
关键词 shear rate shear stress extrapolated shear yield stress plastic viscosity pH value
下载PDF
Relationship between reference value (Wintrobe) of Chinese people's erythrocyte sedimentation rate (ESR) and geographical factors
19
作者 GEMiao YAN Yan +3 位作者 REN Zhi-yuan GUO Cai-ling YUE Da-peng YIN Shu-yan (Department of Geography,Shaanxi Normal University, Xi’an 710062, China) 《Journal of Geographical Sciences》 SCIE CSCD 1999年第2期181-186,共6页
In order to provide a scientific basis for laying out a unified standard of the reference value (Wintrobe) of Chinese people's erythrocyte sedimentation rate (ESR). this paper studies the relationship between the ... In order to provide a scientific basis for laying out a unified standard of the reference value (Wintrobe) of Chinese people's erythrocyte sedimentation rate (ESR). this paper studies the relationship between the reference values (Wintrobe) of Chinese healthy people's ESR, and the test is done according to the Wintrobe Laws and five geographical factors. It is found that the altitude is the modt important factor affecting the reference value (Wintrobe) of Chinese people's ESR. As altitude increases gradually, the reference value (Wintrobe) of people's ESR decreases accordingly, the correlation is quite obvious. By using the method of regression analysis, two multivariate regression equations and ten univariate regression equations are deduced If the geographical index values in a particular area are known, the reference value (Wintrobe) of Chinese people's ESR of this region can be established by means of the regression equations. Furthermore, according to the dependent relationship of the reference value (Wintrobe) of Chinese people's ESR on geographical factors.China can be divided into sin districts: Qinghai-Tibet, Southwest. Northwest. Southeast, North and Northeast China. 展开更多
关键词 erythrocyte sedimentation rate (ESR) reference value geographical elements ALTITUDE HEMORHEOLOGY
下载PDF
Application Research on K/S Value in Determination of Reactive Dyes Fixation Rate
20
作者 FENG Long HAO Qingqing +1 位作者 HU Xuemin YANG Wenxiu 《Journal of Donghua University(English Edition)》 CAS 2021年第4期289-293,共5页
Reactive dyes are the main dyes in printing and dyeing of cellulosic fibers.Reactive dyes fixation rate is a vital indicator to measure the degree of the covalent bond between cellulose and reactive dyes.However,the d... Reactive dyes are the main dyes in printing and dyeing of cellulosic fibers.Reactive dyes fixation rate is a vital indicator to measure the degree of the covalent bond between cellulose and reactive dyes.However,the determination of the fixation rate is tedious and time-consumptive.Based on the theory of reactive dyes dyeing and application of modern computer color matching technology,the relationship between K/S value and the fixation rate with the reactive dyes on cotton fabric was studied.The feasibility of K/S value instead of the traditional washing method for the determination of reactive dyes fixation rate was proved.In this study,the K/S value of the fabric has an excellent linear relationship to the reactive dyes fixation rate obtained by the washing method.The reactive dyes fixation rate can be obtained through the K/S correction value. 展开更多
关键词 reactive dye pure cotton fabric fixation rate Kubelka-Munk function K/S value
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部