学科分类
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15 个结果
  • 简介:一条直接途径被兰姆波浪繁殖在一个稳固的盘子中为累积的秒泛音的一般答案开发了。由兰姆波浪的秒泛音产生的现在的分析集中于基本兰姆波浪的阶段速度确切或近似等于双频率兰姆波浪(DFLW)的盒子。基于获得的一般答案,累积秒泛音回答的数字分析表演与在基本兰姆波浪和主导的DFLW部件的阶段速度之间的刺激来源和差别的位置被联系。

  • 标签: 谐音 波形传播 固体 声学
  • 简介:Tomodelthecumulativedeformationofgranularsoilsundercyclicloading,amathematicalmodelwasproposed.Thepowerlawconnectionbetweentheshearstrainandloadingcyclewasrepresentedbyusingfractionalderivativeapproach.Thevolumetricstrainwascharacterizedbyamodifiedcyclicflowrulewhichconsideredtheeffectofparticlebreakage.Allmodelparameterswereobtainedbythecyclicandstatictriaxialtests.Predictionsofthetestresultswereprovidedtovalidatetheproposedmodel.Comparisonwithanexistingcumulativemodelwasalsomadetoshowtheadvantageoftheproposedmodel.

  • 标签: 下线 服务 迁移
  • 简介:Inthiswork,westudythephotonicbandofcumulativeFibonaccilattices,ofwhichthestructureiscomposedofallgeneratedunitsinaFibonaccisequence.TheresultsarecomparedwithdistributedBraggreflector(DBR)structureswiththesamenumbersoflayers.Photonicbandgapsarefoundattwocharacteristicfrequencies,symmetricallyseparatedfromthecentralbandgapintheDBRcounterpart.FieldamplitudeandphasedistributionintheFibonaccilatticeindicatesaninterferentialoriginofthebandgaps.Fouriertransformontherefractiveindexprofileiscarriedout,andtheresultconfirmsadeterminatelong-rangeperiodicitythatagreeswellwiththephotonicbandstructure.

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  • 简介:CumulativefrequencybvaluewithoutupperboundmagnitudeanditsregressiondeterminationJian-WenSHEN(沈建文)(SeismologicalBureauofAnhuiP...

  • 标签: b VALUE earthquake RECURRENCE relation seismic
  • 简介:AbstractBackground:Despite the recent large number of studies comparing endoscopic and laparoscopic resection for small gastrointestinal stromal tumors (GISTs) (diameter ≤5 cm), the results remain conflicting. The objective of this work was to perform a cumulative meta-analysis to assess the advantages and disadvantages of endoscopic resection vs. laparoscopic resection.Methods:The meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We searched medical databases up to January 2020. Meta-analytical random or fixed effects models were used in pooled analyses. Meta-regression, cumulative meta-analyses, and sub-group analyses were performed to improve the accuracy of the conclusion. Sensitivity analyses were applied to assess the robustness of the results.Results:A total of 12 cohort studies with 1383 participants comparing endoscopic resection and laparoscopic resection were identified, while three cohort studies with 167 participants comparing endoscopic resection and laparoscopic and endoscopic cooperative surgery were found. We found that endoscopic resection had shorter operation times (weighted mean difference [WMD]= -27.1 min, 95% confidence interval [CI]: -40.8 to -13.4 min) and lengths of hospital stay (WMD = -1.43 days, 95% CI: -2.31 to -0.56 days) than did laparoscopic resection. The results were stable and reliable. There were no significant differences in terms of blood loss, hospitalization costs, incidence of complications or recurrence rates. For tumor sizes 2 to 5 cm, endoscopic resection increased the risk of positive margins (relative risk [RR] = 5.78, 95% CI: 1.31-25.46). Although operation times for endoscopic resection were shorter than those of laparoscopic and endoscopic cooperative surgery (WMD = -41.03 min, 95% CI: -59.53 to -22.54 min), there was a higher incidence of complications (RR = 4.03, 95% CI: 1.57-10.34).Conclusions:In general, endoscopic resection is an alternative method for gastric GISTs ≤5 cm. Laparoscopic and endoscopic cooperative surgery may work well in combination. Further randomized controlled trials are recommended to validate or update these results.

  • 标签: Endoscopic resection Laparoscopic resection Gastrointestinal stromal tumors Meta-analysis
  • 简介:城市的总线网络的多客观的优化能帮助改进运输系统的操作效率并且为在中国减少城市的交通拥挤开发策略。工作使用了累积前景理论,当前为在无常下面的决定的最有影响的模型,优化城市的公共汽车网络。完成研究目的,工作开发了城市的总线网络优化,包括的优化原则,优化目的和限制的理论框架。而且,优化目的能包括地从时间,空间和价值的尺寸反映旅客和总线公司的期望。它在以前的研究独自与仅仅一个股东或尺寸相比更科学、合理。另外,为由到理想的答案TOPSIS的类似的顺序偏爱的技术被用来决定积极、否定的理想的选择。在优化选择和理想的选择之间的关联被灰关系分析同时估计。累积前景理论CPT被用来由比较每种选择的全面前景价值决定最好的选择,精确地在实际生活与期望的用途理论相比描述决策行为。最后,Xian的大小写证明方法能更好调整总线网络,并且优化解决方案是更合理的满足实际需要。

  • 标签: 多目标优化 城市公交 公交网络 累积 逼近理想解 TOPSIS
  • 简介:ThesuitabilityofcalculatingatomicmultipolemomentsfromAM1wavefunctionsbycumulativepotential-derivedmethodhasbeeninvestigated.ItisshownthatthismethodhasafasterconvergenceofthefittingprocessandgivesabetterdescriptionofthechargedistributionthantheoriginalPDmethod.Atomicchargesobtainedinthiswayareofcomparablequalitywith6-31G.dataandthecalculateddipolemomentsareclosertotheexperimentaldatathanthevaluescomputeddirectlyfromtheAM1charges.Theresultsdemonstratethattheatomicmultipolemomentshigherthanmonopolemomentcanbeusedtosupplementtheatomicchargetoobtainamoreaccuratedescriptionofchargedistribution.Forthesakeofcomparison,boththeWilliamsfittingpotentialsurfaceandtheConnollyoneareusedinthecalculation.

  • 标签: ATOMIC charge ATOMIC MULTIPOLE MOMENT CUMULATIVE
  • 简介:AbstractObjective:To investigate cumulative live birth rate (cLBR) per oocyte retrieval in infertile patients aged 40 years and over undergoing their first in vitro fertilization/intracytoplasmic sperm injection cycles and to identify the possible predictors.Methods:A total of 1,613 patients at a university hospital in China from January 2013 to May 2017 were enrolled in this retrospective study. All data for fresh and subsequent frozen-thawed cycles were analyzed. Multivariate logistic regression analysis with stepwise selection of possible predictors for cLBR was performed, and Loess curve was constructed to determine the association between cLBR and the number of oocytes retrieved.Results:cLBR significantly increased with the number of oocytes retrieved and reached up to 75% when > 20 oocytes were retrieved (P < 0.001). Variables of antral follicle count (AFC) and the number of oocytes retrieved were selected using multiple logistic regression analysis with stepwise selection to predict the significance of cLBR. cLBR demonstrated an obvious upward trend as the number of oocytes retrieval increased in the Loess curve.Conclusions:For patients aged 40 years and over, AFC and the number of oocytes retrieved were two key predictors for cLBR and maximization of ovarian reserve exploitation was pivotal to increase the chance of live birth.

  • 标签: Advanced Maternal Age Cumulative Live Birth Rate In vitro Fertilization Number of Oocytes Retrieved
  • 简介:Inthiswork,thelaserinducedplasmaplumecharacteristicsandsurfacemorphologyofPt-andAg-iondepositedsiliconwerestudied.Thedepositedsiliconwasexposedtocumulativelaserpulses.Theplasmaplumeimagesproducedbyeachlasershotwerecapturedthroughacomputercontrolledimagecapturingsystemandanalyzedwithimage-Jsoftware.Theintegratedopticalemissionintensityofbothsamplesshowedanincreasingtrendwithincreasingpulses.Ag-iondepositedsiliconshowedhigheropticalemissionintensityascomparedtoPt-iondepositedsilicon,suggestingthatmoredamageoccurredtothesiliconbyAgions,whichwasconfirmedbySRIM/TRIMsimulations.Thesurfacemorphologiesofbothsampleswereexaminedbyopticalmicroscopeshowingthermal,exfoliationalandhydrodynamicalsputteringprocessesalongwiththere-depositionofthematerial,debrisandheataffectedzones’formation.ThecraterofPt-iondepositedsiliconwasdeeperbuthadlesslateraldamagethanAgiondepositedsilicon.Thenovelresultsclearlyindicatedthattheiondepositedsiliconsurfaceproducedincubationcenters,whichledtomoreabsorptionofincidentlightresultingintoahigheremissionintensityfromtheplasmaplumeanddeepercraterformationascomparedtopuresilicon.Theapproachcanbeeffectivelyutilizedinthelaserinducedbreakdownspectroscopytechnique,whichendurespoorlimitsofdetection.

  • 标签: 等离子体羽 离子沉积 激光脉冲 硅表面 表面形态 银离子
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  • 简介:AbstractBackground:Cumulative blood pressure (BP), a measure incorporating the level and duration of BP exposure, is associated with the risk of cardiovascular disease (CVD). However, the level at which cumulative BP could significantly increase the risk remains unclear. This study aimed to investigate the association of 15-year cumulative BP levels with the long-term risk of CVD, and to examine whether the association is independent of BP levels at one examination.Methods:Data from a 26-year follow-up of the Chinese Multi-provincial Cohort Study-Beijing Project were analyzed. Cumulative BP levels between 1992 and 2007 were calculated among 2429 participants free of CVD in 2007. Cardiovascular events (including coronary heart disease and stroke) occurring from 2007 to 2018 were registered. Adjusted hazard ratios (HRs) for CVD incidence associated with quartiles of cumulative systolic blood pressure (SBP) and diastolic blood pressure (DBP) were calculated.Results:Of the 2429 participants, 42.9% (1042) were men, and the mean age in 2007 was 62.1 ± 7.9 years. Totally, 207 CVD events occurred during the follow-up from 2007 to 2018. Participants with higher levels of cumulative SBP or DBP exhibited a higher incidence rate of CVD (P < 0.001). Compared with the lowest quartile of cumulative SBP, the HR for CVD was 1.03 (95% confidence interval [CI]: 0.59-1.81), 1.69 (95% CI: 0.99-2.87), and 2.20 (95% CI: 1.21-3.98) for the second to the fourth quartile of cumulative SBP, and 1.46 (95% CI: 0.86-2.48), 1.99 (95% CI: 1.18-3.35), and 2.08 (95% CI: 1.17-3.71) for the second to the fourth quartile of cumulative DBP, respectively. In further cross-combined group analyses with BP measurements in 2007, 15-year cumulative BP levels higher than the median, that is, 1970.8/1239.9 mmHg·year for cumulative SBP/DBP, which were equivalent to maintaining SBP/DBP levels of 131/83 mmHg or above on average in 15 years, were associated with higher risk of CVD in subsequent years independent of BP measurements at one-time point.Conclusion:Cumulative exposure to moderate elevation of BP is independently associated with increased future cardiovascular risk.

  • 标签: Blood pressure Cardiovascular disease Cohort study
  • 简介:AbstractBackground:More and more scholars have called for the cumulative live birth rate (CLBR) of a complete ovarian stimulation cycle as a key indicator for assisted reproductive technology. This research aims to study the CLBR of the first ovarian hyperstimulation cycles and analyze the related prognosis factors that might affect the CLBR.Methods:Our retrospective study included first in vitro fertilization or intracytoplasmic sperm injection (IVF/ICSI) cycles performed between January 2013 to December 2014. A total of 17,978 couples of first ovarian hyperstimulation IVF/ICSI cycles were included. The study was followed up for 4 years to observe the CLBR. The multivariable logistic regression model was used to analyze the prognosis factor, P value of <0.05 was considered statistically significant.Results:The cumulative pregnancy rate was 58.14% (10,452/17,978), and the CLBR was 49.66% (8928/17,978). The female age was younger in the live birth group when compared with the non-live birth group (30.81 ± 4.05 vs. 33.09 ± 5.13, P < 0.001). The average duration of infertility was shorter than the non-live birth cohort (4.22 ± 3.11 vs. 5.06 ± 4.08, P < 0.001). The preliminary gonadotropin used and the total number of gonadotropin used were lower in the live birth group when compared with the non-live birth group (both P < 0.001). Meanwhile, the number of oocytes retrieved and transferrable embryos were both significantly higher in the live birth group (15.35 ± 7.98 vs. 11.35 ± 7.60, P < 0.001; 6.66 ± 5.19 vs. 3.62 ± 3.51, P < 0.001, respectively).Conclusions:The women’s age, body mass index, duration of infertility years, infertility factors, controlled ovarian hyperstimulation protocol, the number of acquired oocytes, and number of transferrable embryos are the prognosis factors that significantly affected the CLBR.

  • 标签: Cumulative live birth rates IVF ICSI Controlled ovarian hyperstimulation In vitro fertilization Intracytoplasmic sperm injection