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Bending Strength of Glass Materials under Strong Dynamic Impact and Its Strain Rate Effects
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作者 LIU Xiaogen QI Shuang +2 位作者 WEI Shaoshan WAN Detian JIN Chunxia 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第6期1358-1364,共7页
Based on the structural characteristics of the high-speed loading tester,a four-point bending test device was designed to carry out the four-point bending strength test of glass under the action of static load and dif... Based on the structural characteristics of the high-speed loading tester,a four-point bending test device was designed to carry out the four-point bending strength test of glass under the action of static load and different impact velocities,and the formulae for calculating the maximum dynamic stress and strain rate of glass specimens under the action of impact loads were derived.The experimental results show that the bending strength values of the glass under dynamic impact loading are all higher than those under static loading.With the increase of impact speed,the bending strength value of glass specimens generally tends to increase,and the bending strength value increases more obviously when the impact speed exceeds 0.5 m/s or higher.By increasing the impact velocity,higher tensile strain rate of glass specimens can be obtained because the load action time becomes shorter.The bending strength of the glass material increases with its tensile strain rate,and when the tensile strain rate is between 0 and 2 s^(-1),the bending strength of the glass specimen grows more obviously with the strain rate,indicating that the glass bending strength is particularly sensitive to the tensile strain rate in this interval.As the strain rate increases,the number of cracks formed after glass breakage increases significantly,thus requiring more energy to drive the crack formation and expansion,and showing the strain rate effect of bending strength at the macroscopic level.The results of the study can provide a reference for the load bearing and structural design of glass materials under dynamic loading. 展开更多
关键词 glass materials strong dynamic impact bending strength strain rate effect dynamic enhancement factor
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Effect of Health Management in Raising Awareness Rate of Disease Prevention and Treatment in Patients with Prehypertension
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作者 Jing Huang 《Journal of Biosciences and Medicines》 2024年第2期236-243,共8页
Objective: To analyze the effect of health management on improving the awareness rate of disease prevention and treatment in patients with prehypertension, so as to provide guidance for clinical management of patients... Objective: To analyze the effect of health management on improving the awareness rate of disease prevention and treatment in patients with prehypertension, so as to provide guidance for clinical management of patients with prehypertension. Methods: 108 patients diagnosed with prehypertension in our hospital were divided into a control group and an experimental group. The control group was not given management measures, while the experimental group was given health management. The incidence of hypertension and cognition level of hypertension knowledge were compared between the two groups after management. Results: The incidence of hypertension in the experimental group was 7.41% lower than that in the control group 29.63%. The cognitive level of hypertension in the patients (66.54 ± 1.25) was significantly higher than that in the patients without health management (41.45 ± 2.45), and P < 0.05;Conclusion: For patients with prehypertension, the implementation of health management is helpful to improve their cognition of hypertension, master related prevention knowledge, and reduce the incidence of hypertension. 展开更多
关键词 effect of Health Management in Raising Awareness rate of Disease Prevention and Treatment in Patients with Prehypertension
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Evaluation of the Effectiveness and Efficiency of the Combination of Levamlodipine Besylate and Valsartan in the Treatment of Hypertension
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作者 Dazhuan Li 《Proceedings of Anticancer Research》 2024年第1期92-98,共7页
Objective:To investigate the effectiveness and efficiency of combining levamlodipine besylate and valsartan in the treatment of hypertension.Methods:This study selected 28 patients with hypertension as observation sub... Objective:To investigate the effectiveness and efficiency of combining levamlodipine besylate and valsartan in the treatment of hypertension.Methods:This study selected 28 patients with hypertension as observation subjects.The treatment duration ranged from January 2020 to June 2023.Using the random number table method,patients were divided into two groups.The control group received treatment with valsartan,while the observation group received a combination of valsartan and levamlodipine besylate.Therapeutic effects and safety were compared between the groups,and changes in the patient’s blood pressure and renal function index levels were assessed.Results:The total clinical effective rate of the observation group was significantly higher than that of the control group(P<0.05).The observation group demonstrated better diastolic blood pressure,systolic blood pressure,and renal function indicators compared to the control group(P<0.05).There was no significant difference in the incidence of adverse reactions between the two groups(P>0.05).Conclusion:The combined treatment of levamlodipine besylate and valsartan in patients with hypertension showed significant clinical efficacy and holds broad application value. 展开更多
关键词 Levamlodipine besylate VALSARTAN HYPERTENSION Renal function effective rate
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Impact of cooling rate on mechanical properties and failure mechanism of sandstone under thermal-mechanical coupling effect 被引量:1
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作者 Pingye Guo Peng Zhang +2 位作者 Mohua Bu Hang Xing Manchao He 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第2期97-116,共20页
High geo-temperature is one of the inevitable geological disasters in deep engineering such as resource extraction,space development,and energy utilization.One of the key issues is to understand the mechanical propert... High geo-temperature is one of the inevitable geological disasters in deep engineering such as resource extraction,space development,and energy utilization.One of the key issues is to understand the mechanical properties and failure mechanism of high-temperature rock disturbed by low-temperature airflow after excavation.Therefore,.the experimental and numerical investigation were carried out to study the impact of cooling rate on mechanical properties and failure mechanism of high temperature sandstone.First,uniaxial compression experiments of high temperature sandstone at different real-time cooling rates were carried out to study the mechanical properties and failure modes.The experimental results indicate that the cooling rate has a significant effect on the mechanical properties and failure modes of sandstone.The peak strain,peak stress,and elastic modulus decrease with an increase in cooling rate,and the fragmentation degree after failure increases gradually.Moreover,the equivalent numerical model of heterogeneous sandstone was established using particle flow code(PFC)to reveal the failure mechanism.The results indicate that the sandstone is dominated by intragrain failure in the cooling stage,the number of microcracks is exponentially related to the cooling rate,and the higher the cooling rate,the more cracks are concentrated in the exterior region.Under axial loading,the tensile stress is mostly distributed along the radial direction,and the damage in the cooling stage is mostly due to the fracture of the radial bond.In addition,axial loading,temperature gradient and thermal stress mismatch between adjacent minerals are the main reasons for the damage of sandstone in the cooling stage.Moreover,the excessive temperature gradient in the exterior region of the sandstone is the main reason for the damage concentration in this region. 展开更多
关键词 High geo-temperature Thermo-mechanical coupling effect Cooling rate SANDSTONE PFC
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Laser-assisted Simulation of Dose Rate Effects of Wide Band Gap Semiconductor Devices
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作者 TANG Ge XIAO Yao +3 位作者 SUN Peng LIU Jingrui ZHANG Fuwang LI Mo 《原子能科学技术》 EI CAS CSCD 北大核心 2023年第12期2314-2325,共12页
Laser-assisted simulation technique has played a crucial role in the investigation of dose rate effects of silicon-based devices and integrated circuits,due to its exceptional advantages in terms of flexibility,safety... Laser-assisted simulation technique has played a crucial role in the investigation of dose rate effects of silicon-based devices and integrated circuits,due to its exceptional advantages in terms of flexibility,safety,convenience,and precision.In recent years,wide band gap materials,known for their strong bonding and high ionization energy,have gained increasing attention from researchers and hold significant promise for extensive applications in specialized environments.Consequently,there is a growing need for comprehensive research on the dose rate effects of wide band gap materials.In response to this need,the use of laser-assisted simulation technology has emerged as a promising approach,offering an effective means to assess the efficacy of investigating these materials and devices.This paper focused on investigating the feasibility of laser-assisted simulation to study the dose rate effects of wide band gap semiconductor devices.Theoretical conversion factors for laser-assisted simulation of dose rate effects of GaN-based and SiC-based devices were been provided.Moreover,to validate the accuracy of the conversion factors,pulsed laser and dose rate experiments were conducted on GaN-based and SiC-based PIN diodes.The results demonstrate that pulsed laser radiation andγ-ray radiation can produce highly similar photocurrent responses in GaN-based and SiC-based PIN diodes,with correlation coefficients of 0.98 and 0.974,respectively.This finding reaffirms the effectiveness of laser-assisted simulation technology,making it a valuable complement in studying the dose rate effects of wide band gap semiconductor devices. 展开更多
关键词 laser-assisted simulation dose rate effect wide band gap semiconductor conversion factor
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Readmission rate and early complications in patients undergoing total knee arthroplasty:A retrospective study
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作者 Tushar Jethi Deepak Jain +1 位作者 Rajnish Garg Harpal Singh Selhi 《World Journal of Orthopedics》 2024年第8期713-721,共9页
BACKGROUND Total knee arthroplasty(TKA)can improve pain,quality of life,and functional outcomes.Although uncommon,postoperative complications are extremely consequential and thus must be carefully tracked and communic... BACKGROUND Total knee arthroplasty(TKA)can improve pain,quality of life,and functional outcomes.Although uncommon,postoperative complications are extremely consequential and thus must be carefully tracked and communicated to patients to assist their decision-making before surgery.Identification of the risk factors for complications and readmissions after TKA,taking into account common causes,temporal trends,and risk variables that can be changed or left unmodified,will benefit this process.AIM To assess readmission rates,early complications and their causes after TKA at 30 days and 90 days post-surgery.METHODS This was a prospective and retrospective study of 633 patients who underwent TKA at our hospital between January 1,2017,and February 28,2022.Of the 633 patients,28 were not contactable,leaving 609 who met the inclusion criteria.Both inpatient and outpatient hospital records were retrieved,and observations were noted in the data collection forms.RESULTS Following TKA,the 30-day and 90-day readmission rates were determined to be 1.1%(n=7)and 1.8%(n=11),respectively.The unplanned visit rate at 30 days following TKA was 2.6%(n=16)and at 90 days was 4.6%(n=28).At 90 days,the unplanned readmission rate was 1.4%(n=9).Reasons for readmissions included medical(27.2%,n=3)and surgical(72.7%,n=8).Unplanned readmissions and visits within 90 days of follow-up did not substantially differ by age group(P=0.922),body mass index(BMI)(P=0.633),unilateral vs bilateral TKA(P=0.696),or patient comorbidity status(30-day P=0.171 and 90-day P=0.813).Reoperation rates after TKA were 0.66%(n=4)at 30 days and 1.15%(n=8)at 90 days.The average length of stay was 6.53 days.CONCLUSION In this study,there was a low readmission rate following TKA.There was no significant correlation between readmission rate and patient factors such as age,BMI,and co-morbidity status. 展开更多
关键词 Total knee arthroplasty Length of stay READMISSION rates CAUSES Risk factors PROSPECTIVE RETROSPECTIVE follow-up REOPERATION
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Research on the Intervention Effect of Vibroacoustic Therapy in the Treatment of Patients with Depression
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作者 Xiaodan Wang Zheng Xie Guiping Du 《International Journal of Mental Health Promotion》 2024年第2期149-160,共12页
Research purpose:This study implemented somatosensory music therapy on patients with depressive disorders,and explored the effects of somatosensory music therapy on the degree of depression,positive and negative emoti... Research purpose:This study implemented somatosensory music therapy on patients with depressive disorders,and explored the effects of somatosensory music therapy on the degree of depression,positive and negative emotions,intuitive stress and autonomic nervous function of patients.Research method:We collected 66 patients diagnosed with depression from the Department of Psychological Medicine of Henan Provincial People’s Hospital,and divided them into a control group and an intervention group according to the random number table,with 33 people in each group.The control group received routine psychiatric treatment and nursing.On the basis of the control group,the intervention group received somatosensory music therapy 3 times a week,30 min each time,for 4 consecutive weeks.The Hamilton Depression Scale,Positive and Negative Emotion Scale,Perceived Stress Scale,and Heart Rate Variability Index were collected and analyzed at baseline(T0),2 weeks after treatment(T1)and 4 weeks after treatment(T2).Research results:After 4 weeks of treatment,the HAMD scores of the two groups decreased to varying degrees,and the difference between the groups was statistically significant(p<0.05).After 4 weeks of treatment,the scores of positive emotions in both groups increased to varying degrees,and the scores of negative emotions increased to varying degrees.The scores decreased to varying degrees,and there were statistically significant differences between the positive and negative emotion groups(p<0.05).After 4 weeks of treatment,the CPSS scores of the two groups decreased to varying degrees,and the difference between the two groups was statistically significant(p<0.05).Analyzing the main effect of intervention factors alone,after 4 weeks of treatment,SDNN and RMSSD indexes all increased to varying degrees,and the degree of increase in the intervention group was greater than that in the control group,and the difference between the groups was statistically significant(p<0.05).Research conclusion:assisting somatosensory music therapy for patients with depressive disorders can improve depressive symptoms,increase positive emotions,reduce negative emotions,and reduce perceived stress.These are beneficial to restore the balance of autonomic nervous system,and are effective for the treatment of depression. 展开更多
关键词 Somatosensory music depressive disorder intervention effect perceived stress heart rate variability
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Risk factors for recurrence of common bile duct stones after surgical treatment and effect of ursodeoxycholic acid intervention
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作者 Wei-Hong Yuan Zheng Zhang +2 位作者 Qi Pan Bo-Neng Mao Tao Yuan 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第1期103-112,共10页
BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)is an accurate diagnostic method for choledocholithiasis and treatment option for stone removal.Additionally,ursodeoxycholic acid(UDCA)can dissolve choles... BACKGROUND Endoscopic retrograde cholangiopancreatography(ERCP)is an accurate diagnostic method for choledocholithiasis and treatment option for stone removal.Additionally,ursodeoxycholic acid(UDCA)can dissolve cholesterol stones and prevent their development and reappearance by lowering the cholesterol concen-tration in bile.Despite these treatment options,there are still patients who experience stone recurrence.The clinical data of 100 patients with choledochal stones who were hospitalized at the Yixing People’s Hospital and underwent ERCP for successful stone extraction between June 2020 and December 2022 were retrospectively collected.According to the post-ERCP treatment plan,100 patients were classified into UDCA(n=47)and control(n=53)groups.We aimed to assess the clinical efficacy and rate of relapse in the two patient populations.We then collected information(basic demographic data,clinical characteristics,and serum biochemical indicators)and determined the factors contributing to relapse using logistic regression analysis.Our secondary goal was to determine the effects of UDCA on liver function after ERCP.Compared to the control group,the UDCA group demonstrated a higher clinical effectiveness rate of 92.45%vs 78.72%(P<0.05).No significant differences were observed in liver function indices,including total bilirubin,direct bilirubin,gamma-glutamyl transpeptidase,alanine aminotransferase,alkaline phosphatase,and aspartate aminotransferase,between the two groups before treatment.After treatment,all liver function indices were significantly reduced.Comparing the control vs UDCA groups,the UDCA group exhibited significantly lower levels of all indices(55.39±6.53 vs 77.31±8.52,32.10±4.62 vs 45.39±5.69,142.32±14.21 vs 189.63±16.87,112.52±14.25 vs 149.36±15.36,122.61±16.00 vs 171.33±22.09,96.98±10.44 vs 121.35±11.57,respectively,all P<0.05).The stone recurrence rate was lower in the UDCA group(13.21%)in contrast with the control group(44.68%).Periampullary diverticula(OR:6.00,95%CI:1.69-21.30),maximum stone diameter(OR:1.69,95%CI:1.01-2.85),stone quantity>3(OR:4.23,95%CI:1.17-15.26),and positive bile culture(OR:7.61,95%CI:2.07-27.91)were independent factors that influenced the relapse of common bile duct stones after ERCP(P<0.05).Furthermore,postoperative UDCA was identified as a preventive factor(OR:0.07;95%CI:0.08-0.09).CONCLUSION The intervention effect of UDCA after ERCP for common bile duct stones is adequate,providing new research directions and references for the prevention and treatment of stone recurrence. 展开更多
关键词 Endoscopic retrograde cholangiopancreatography RECURRENCE Ursodeoxycholic acid Common bile duct stones Clinical effective rate Risk factors
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Environmental Impact Assessment Follow-Up of Seismic Survey Offshore Activities in Brazil
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作者 Fontes Nuno Eduardo Paulo Marcelo Montaño 《Journal of Environmental Protection》 2024年第2期141-155,共15页
Follow-up of environmental impacts is an integral part of the Environmental Impact Assessment (EIA) process, closely related to the effectiveness of the instrument. EIA follow-up has been receiving a lot of interest f... Follow-up of environmental impacts is an integral part of the Environmental Impact Assessment (EIA) process, closely related to the effectiveness of the instrument. EIA follow-up has been receiving a lot of interest from scientists and practitioners, though it is recognized as one of the weakest points of EIA systems globally. Also, EIA follow-up is influenced by the context, mainly in terms of the types of projects or activities and their related impacts on the environment. Therefore, the present paper is focused on the investigation of the follow-up stage applied to the activity of seismic survey coupled with offshore oil & gas exploitation in Brazil. Research was based on a qualitative approach that included document analysis and semi-structured interviews with analysts involved in EIA processes, and sought to generate evidence of effectiveness of the EIA follow-up as conducted by the Federal Environment Agency (Ibama) in order to situate the practice of follow-up in the broader context of international best practice principles. Based on the findings, it was concluded that, due to the peculiarities of offshore seismic survey, it is necessary to promote adaptations in the procedures for monitoring impacts in order to ensure proper alignment with the principles and conceptual foundations that guide EIA practice. Specifically, the timing of the execution of the activity imposes challenges for its integration into the “conventional” cycle that has guided the monitoring of the impacts in the EIA of projects. 展开更多
关键词 Environmental Impact Assessment follow-up follow-up effectiveness Oil and Gas Offshore Seismic Survey
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Contemporary Global Issue of Rising Water Scarcity for Agriculture: The Quest for Effective and Feasible Soil Moisture and Free-Water Surface Conservation Strategies
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作者 Sunday E. Obalum Gloria I. Ezenne +1 位作者 Yoshinori Y. Watanabe Toshiyuki Wakatsuki 《Journal of Water Resource and Protection》 2011年第3期166-175,共10页
There is the need to take seriously the task of conserving soil moisture in agricultural fields and free-water surfaces in reservoirs, especially in recent years of climate change. Many strategies exist for achieving ... There is the need to take seriously the task of conserving soil moisture in agricultural fields and free-water surfaces in reservoirs, especially in recent years of climate change. Many strategies exist for achieving this task and improving the productivity of arable soils. These strategies traditionally come under biological and physical or mechanical measures. Some other relatively new techniques operate neither on physical nor on biological principle. All these measures which operate on different principles frequently overlap. The principles involved, together with the prospects and constraints of the key techniques of conserving soil moisture found in the literature, are reviewed in this paper. Among other considerations, the effectiveness and/or practicability of any one of the techniques depend upon soil type, topography, climate, scale of production, level of technology, and socio-economic status. Such agronomic practices as conservation tillage and live vegetation mulch that maintain infiltration rates often appear to be more beneficial in the long run than engineering structures, especially those that lead to blocking of waterways on the soil surface. However, this review reveals that none of the soil moisture conservation strategies could be credited as universally applicable. Consequently, an integrated approach to soil water management and conservation, where feasible, is considered more appropriate. This is because the different principles involved in the techniques identified to be compatible would readily complement and strengthen one another. Such a multi-mechanistic approach is expected to result in improved efficacy in conserving water resources in soils and open reservoirs. 展开更多
关键词 effective Rainfall EVAPOTRANSPIRATION rate Deep PERCOLATION Losses to SEEPAGE Integrated Soil Moisture Conservation Strategies
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Clinical Application of Monitoring Glomerular Filtration Rate and Effective Renal Plasma Flow
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作者 姚薇萱 常国钧 +3 位作者 徐兆强 马玉琪 林戟 李永军 《The Journal of Biomedical Research》 CAS 1997年第1期26-29,共4页
Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured by SPECT in 172 patients (192 times) with renal impairment due to various diseases and also in 18 normal controls. The results sugg... Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were measured by SPECT in 172 patients (192 times) with renal impairment due to various diseases and also in 18 normal controls. The results suggest that GFR and ERPF are sensitive and efficient renal function indicators in monitoring the change of the disease and assessing therapeutic effect. However, they should be checked carefully because of many factors affect the resutls of the measurement. 展开更多
关键词 glomerular filtration rate (GFR) effective renal plasma flow (ERPF) renal function
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Proposal for a Tax Rate Swap to Shield Against the Gap Between Statutory and Effective Tax Rates-A Boost for Entrepreneurship and a Motive for New Investments
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作者 Nicholas Belesis Nansy Karali Christina Heliotis 《Management Studies》 2021年第2期137-152,共16页
This paper focuses on a common problem for entrepreneurs and investors:the uncertainty around the actual tax rate,which is the percent of net income that a corporation pays in taxes.This uncertainty results from a dif... This paper focuses on a common problem for entrepreneurs and investors:the uncertainty around the actual tax rate,which is the percent of net income that a corporation pays in taxes.This uncertainty results from a difference(i.e.,a gap)between the statutory and the effective tax rate,which is the actual tax rate.This gap results from the legal framework which provides that certain types of incomes and expenses are not considered income.This gap causes significant uncertainty and may hinder entrepreneurship.This paper studies this gap in seven OECD countries(Austria,Canada,France,Germany,Italy,UK,and USA)and Brazil.We selected the 10 top-listed companies of each country and calculated the gaps for the period 2016-2019.Our findings proved that these gaps are unstable and may differ between companies of the same country and between countries.In addition,gaps of specific companies may change over time.The key outcome of this paper is the proposal of a new derivative tax rate swap.Using this derivative,governments will be able to eliminate the gap of specific companies,attract new investment,and increase entrepreneurship. 展开更多
关键词 tax rate swap corporate taxes statutory tax rate effective tax rate INVESTMENTS ENTREPRENEURSHIP
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Evaluation of the Effect and Efficiency of Ear Tip Bloodletting Combined with Xianfang Huoming Yin in the Treatment of Early-Stage Wheals
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作者 Ying Pang 《Journal of Clinical and Nursing Research》 2024年第2期86-91,共6页
Objective:To evaluate the effect and efficiency of ear tip bloodletting combined with Xianfang Huoming Yin(XFH)in the treatment of early-stage wheals.Methods:70 patients with early-stage wheals admitted from September... Objective:To evaluate the effect and efficiency of ear tip bloodletting combined with Xianfang Huoming Yin(XFH)in the treatment of early-stage wheals.Methods:70 patients with early-stage wheals admitted from September 2020 to September 2022 were divided into two groups by randomized numerical table method,with 35 cases/group.Both groups received conventional treatment,the control group combined with XFH,and the observation group combined with ear tip bloodletting therapy and XFH.Conscious symptom scores,ocular indexes,therapeutic effects,and sleep quality between the two groups were compared.Results:After the treatment,the patients in the observation group had lower self-awareness symptom scores and sleep quality scores as compared to those in the control group;the diameter of the mass in the observation group was smaller than that of the control group after treatment;the average tear film rupture time and the time taken for the first non-contact tear film to rupture were longer in the observation group than those in the control group;the total effective rate of the treatment in the observation group was higher than that of the control group(P<0.05).Conclusion:Ear tip bloodletting combined with XFH was ideal for the treatment of early-stage wheals and has a high effective rate. 展开更多
关键词 Early stage of wheal Ear tip bloodletting Xianfang huoming yin effective rate
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Testification on Effectiveness of Average or Weight-added Internal Rate of Return
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作者 Xiaoshui Yu Guojie Zhao 《Chinese Business Review》 2006年第1期60-63,共4页
It seems that an effective way of how to make the right choice of Various investment projects is based on the theory of average internal income rate, or the theory of weight-added internal income rate. With several ex... It seems that an effective way of how to make the right choice of Various investment projects is based on the theory of average internal income rate, or the theory of weight-added internal income rate. With several examples of numerical value, this paper proves that this method is not as effective as expected, but indirectly testifies that only with the principle of maximization of NPV that independent projects can be the best combination of projects with limited investment that is achieved. 展开更多
关键词 average internal income rate weight-added internal income rate combination of independent projects testification of effectiveness
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Strain-rate effect on initial crush stress of irregular honeycomb under dynamic loading and its deformation mechanism 被引量:4
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作者 Peng Wang Zhijun Zheng +1 位作者 Shenfei Liao Jilin Yu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2018年第1期117-129,共13页
The seemingly contradictory understandings of the initial crush stress of cellular materials under dynamic loadings exist in the literature, and a comprehensive analysis of this issue is carried out with using direct ... The seemingly contradictory understandings of the initial crush stress of cellular materials under dynamic loadings exist in the literature, and a comprehensive analysis of this issue is carried out with using direct information of local stress and strain. Local stress/strain calculation methods are applied to determine the initial crush stresses and the strain rates at initial crush from a cell-based finite element model of irregular honeycomb under dynamic loadings. The initial crush stress under constant-velocity compression is identical to the quasi-static one, but less than the one under direct impact, i.e. the initial crush stresses under different dynamic loadings could be very different even though there is no strain-rate effect of matrix material. A power-law relation between the initial crush stress and the strain rate is explored to describe the strain-rate effect on the initial crush stress of irregular honeycomb when the local strain rate exceeds a critical value, below which there is no strain-rate effect of irregular honeycomb. Deformation mechanisms of the initial crush behavior under dynamic loadings are also explored.The deformation modes of the initial crush region in the front of plastic compaction wave are different under different dynamic loadings. 展开更多
关键词 Cellular material Constant-velocity compression Direct impact Cross-sectional stress Initial crush stress Strain rate effect
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Model Building of the Initial Crown Effect Rate in 4-High Mill 被引量:2
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作者 Jianzhong XU, Dianyao GONG, Wencai ZHANG, Xianwen CHANG, Xianghua LIU and Guodong WANG State Key Laboratory of Rolling Technology and Automation, Northeastern University, PO. Box 105, Shenyang 110004, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第2期165-169,共5页
The code for calculating the crown effect rate of hot strip steel Was developed using the effect function method. The effect of the initial crown on the crown of the product in hot strip rolling was investigated. The ... The code for calculating the crown effect rate of hot strip steel Was developed using the effect function method. The effect of the initial crown on the crown of the product in hot strip rolling was investigated. The coefficients of a polynomial of degree six for calculating the base value of initial crown effect rate in 4-high mill were determined and the compensation factors of per unit width rolling force, bending force, work roll crown and draft on the initial crown effect rate were given. The difference between the calculation result by established model and theoretical value obtained by effect function method was 4.88 μm when the strip width was 1.85 m. 展开更多
关键词 4-high mill effect function Hot rolling strip effect rate
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Effectiveness of MRA on embolized intracranial aneurysms: a comparison of DSA, CE-MRA, and TOF-MRA 被引量:5
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作者 Ally Mohamed Qassim Sheng Guan +2 位作者 Halfan Saidi Ngowo Binghui Liu Haowen Xu 《Journal of Interventional Medicine》 2018年第1期32-41,共10页
Purpose: The endovascular treatment of intracranial aneurysms was proven safe and effective compared to the alternative method of surgical clipping, despite the high recurrence rate. Follow-up of embolized intracrania... Purpose: The endovascular treatment of intracranial aneurysms was proven safe and effective compared to the alternative method of surgical clipping, despite the high recurrence rate. Follow-up of embolized intracranial aneurysms is mandatory for the early detection of recurrence and improved outcomes. DSA is used as the reference standard for this assessment. To determine the effectiveness of MRA in follow-up evaluations of intracranial aneurysms after embolization by comparing DSA, CE-MRA, and TOF-MRA. Materials and Methods: Sixty-eight consecutive patients undergoing DSA, TOF-MRA, and CE-MRA during an interval of <1 week were enrolled in this 6-month study. Images were evaluated for occlusion status, patency of the parent vessels, and artifacts. The modified Raymond-Roy occlusion classification and Aneurysm Embolization Grades were used to assess the occlusion status and initial DSA images for detection of recurrence in two filtered study phases with optimized selection criteria. Seventeen observers(phase I: 9, phase II: 8) independently interpreted the double-blinded images. Agreement was expressed with a Fleiss kappa value; p < 0.05 was considered significant. Results: This study included 68 patients with 77 aneurysms; 38(49.35%) were treated with coil alone and 39(50.65%) with stent-assisted coiling. In both phases, DSA was superior to TOF-MRA and CE-MRA using MRRC(Phase I: k = 0.567, p ≤ 0.001; k = 0.287, p ≤ 0.001; k = 0.117, p ≤ 0.001, respectively; Phase II: k = 0.503, p ≤ 0.001; k = 0.303, p ≤ 0.001; k = 0.115, p = 0.038, respectively). TOF-MRA was as effective as DSA(TOF: k = 0.335, p ≤ 0.001; DSA: k = 0.323, p ≤ 0.001) for recurrence detection. Conclusion: We suggest TOF-MRA as a first-line follow-up tool to detect aneurysm recurrence, and DSA to quantify the filling space to make a definite decision on re-embolization. 展开更多
关键词 effectiveNESS follow-up INTRACRANIAL ANEURYSMS MRA DSA
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Effect of montmorillonite on hydrate-based methane separation from mine gas 被引量:7
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作者 ZHANG Qiang WU Qiang +2 位作者 ZHANG Hui ZHANG Bao-yong XIA Ting 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第1期38-50,共13页
Three types of mine gas samples were used in the solutions of tetrahydrofuran(THF),sodium dodecyl sulfate(SDS)and THF-SDS with/without MMT respectively to investigate the effect of montmorillonite(MMT)on separation ch... Three types of mine gas samples were used in the solutions of tetrahydrofuran(THF),sodium dodecyl sulfate(SDS)and THF-SDS with/without MMT respectively to investigate the effect of montmorillonite(MMT)on separation characteristics of methane recovered from mine gas based on hydrate method.The partition coefficient,separation factor and recovery rate were used to evaluate the effects of MMT,and the selection factor was primarily proposed to define the selectivity of mine gas hydrate in the relative target gases.The experimental results indicate that MMT could improve the following factors including hydration separation factor,the selection factor,the partition coefficient,and the recovery rate.Furthermore,the effect of SDS on the function of MMT is analyzed in the process of hydration separation.Finally,due to the results of the experiment,it is concluded that MMT hydration mechanism explores the effect of MMT enrichment methane from mine gas. 展开更多
关键词 mine gas HYDrate MONTMORILLONITE separation effect partition coefficient separation factor recovery rate selection factor
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Mechanical properties of deep sandstones under loading rate effect 被引量:4
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作者 ZHANG Jun-wen DING Lu-jiang +2 位作者 SONG Zhi-xiang FANWen-bing WANG Shan-yong 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第6期1933-1944,共12页
The advance speed of the working face in coal mines can significantly affect the fluctuation frequency of abutment pressure in front of the coal body.Moreover,it has a certain correlation with the change of axial load... The advance speed of the working face in coal mines can significantly affect the fluctuation frequency of abutment pressure in front of the coal body.Moreover,it has a certain correlation with the change of axial loading rate in coal and rock mechanics test.Therefore,uniaxial compression tests under various loading rates of 0.05,0.1,0.15,0.25,0.5 MPa/s were conducted using 2000 kN triaxial testing machine and PCI-2 acoustic emission test system to study the loading rate effect on the mechanical properties of deep sandstones.The results show that 1)the peak strength and elastic modulus of the deep sandstone increase with the loading rate increasing;2)with the loading rate increasing,the deep sandstone transforms from plastic-elastic-plastic to plastic-elastic and moreover,the failure mode gradually transfers from type I to type III;3)With the loading rate increasing,the total input strain energy,elastic strain energy,and dissipated strain energy generally increase;4)the damage variable presents the evolution characteristics of inverted“S”shape with time,and with the loading rate increasing,the damage degree of the deep sandstone is aggravated.The conclusion obtained can provide the theoretical basis for the stability control of the surrounding rock in deep engineering. 展开更多
关键词 loading rate effect failure mode energy evolution damage evolution mechanical properties deep sandstone
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Research on effectiveness of coal mine safety supervision system reform on three types of collieries in China 被引量:7
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作者 Quanlong Liu Xinchun Li Fuyuan Guan 《International Journal of Coal Science & Technology》 EI CAS 2014年第3期376-382,共7页
Coal mine safety supervision system plays an important role in the coal mine safety management in China.However,the current supervision system is established on the basis of learning the advanced experience from other... Coal mine safety supervision system plays an important role in the coal mine safety management in China.However,the current supervision system is established on the basis of learning the advanced experience from other developed countries.It needs to be further improved according to national conditions.Therefore,the effectiveness of coal mine safety supervision system reform on three types of collieries are assessed by using time series analysis method based on comparative analysis of the supervision system before and after the reform in this paper.The regression results show that the structural reform is not conductive to the improvement of coal mine safety situation in the short term,but conductive significantly in the long term.Specifically,the effects in township coal mines are more significant than stateowned key coal mines in the long run,but negative effects also exist in the short term.The negative effects in state-owned key coal mines are non-significant compared with township coal mines.Moreover,the regression results are analyzed from the aspects of the closure policy of illegal small township coal mines at the end of 1998 and shortage of the new supervision system.Finally,the suggestions on improving the new supervision system are put forward based on the above analysis. 展开更多
关键词 Coal mine safety supervision Time series analysis Sinuctural reform Death rate per million tonnes effectiveness of supervision
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