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Cumulative effects of stress-sensitivity factors on depressive symptoms and suicide risk:A prospective study
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作者 Xue-Mei Qin Meng-Qi Xu +20 位作者 Ya-Qi Qin Fang-Zhou Shao Mo-Han Ma Wen-Wen Ou Guan-Yi Lv Qian-QianZhang Wen-Tao Chen Xiao-Tian Zhao Ao-Qian Deng Jin-Tao Xiong Ling-Si Zeng Yi-Lin Peng Mei Huang Shu-Yin Xu Mei Liao Li Zhang Ling-Jiang Li Yu-Meng Ju Jin Liu Bang-Shan Liu Yan Zhang 《World Journal of Psychiatry》 2025年第2期173-185,共13页
BACKGROUND Sensitivity to stress is essential in the onset,clinical symptoms,course,and prognosis of major depressive disorder(MDD).Meanwhile,it was unclear how variously classified but connected stress-sensitivity va... BACKGROUND Sensitivity to stress is essential in the onset,clinical symptoms,course,and prognosis of major depressive disorder(MDD).Meanwhile,it was unclear how variously classified but connected stress-sensitivity variables affect MDD.We hypothesize that high-level trait-and state-related stress-sensitivity factors may have different cumulative effects on the clinical symptoms and follow-up outcomes of MDD.AIM To investigate how stress-sensitivity factors added up and affected MDD clinical symptoms and follow-up results.METHODS In this prospective study,281 MDD patients were enrolled from a tertiary care setting.High-level stress-sensitivity factors were classified as trait anxiety,state anxiety,perceived stress,and neuroticism,with a total score in the top quartile of the research cohort.The cumulative effects of stress-sensitivity factors on cognitive dysfunction,disability and functional impairment,suicide risk,and depressive and anxiety symptoms were examined using an analysis of variance with linear trend analysis.Correlations were investigated further using multiple regression analysis.RESULTS Regarding high-level stress-sensitivity factors,53.40%of patients had at least one at baseline,and 29.61%had two or more.Four high-level stress-sensitivity components had significant cumulative impacts on MDD symptoms at baseline(all P<0.001).Perceived stress predicted the greatest effect sizes of state-related factors on depressive symptoms(partialη^(2)=0.153;standardizedβ=0.195;P<0.05).The follow-up outcomes were significantly impacted only by the high-level trait-related components,mainly when it came to depressive symptoms and suicide risk,which were predicted by trait anxiety and neuroticism,respectively(partialη^(2)=0.204 and 0.156;standardizedβ=0.247 and 0.392;P<0.05).CONCLUSION To enhance outcomes of MDD and lower the suicide risk,screening for stress-sensitivity factors and considering multifaceted measures,mainly focusing on trait-related ones,should be addressed clinically. 展开更多
关键词 Major depressive disorder Stress sensitivity Depressive symptoms Suicide risk cumulative effect
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Cumulative effects of excess high-normal alanine aminotransferase levels in relation to new-onset metabolic dysfunction-associated fatty liver disease in China 被引量:7
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作者 Jing-Feng Chen Zhuo-Qing Wu +5 位作者 Hao-Shuang Liu Su Yan You-Xiang Wang Miao Xing Xiao-Qin Song Su-Ying Ding 《World Journal of Gastroenterology》 SCIE CAS 2024年第10期1346-1357,共12页
BACKGROUND Within the normal range,elevated alanine aminotransferase(ALT)levels are associated with an increased risk of metabolic dysfunction-associated fatty liver disease(MAFLD).AIM To investigate the associations ... BACKGROUND Within the normal range,elevated alanine aminotransferase(ALT)levels are associated with an increased risk of metabolic dysfunction-associated fatty liver disease(MAFLD).AIM To investigate the associations between repeated high-normal ALT measurements and the risk of new-onset MAFLD prospectively.METHODS A cohort of 3553 participants followed for four consecutive health examinations over 4 years was selected.The incidence rate,cumulative times,and equally and unequally weighted cumulative effects of excess high-normal ALT levels(ehALT)were measured.Cox proportional hazards regression was used to analyse the association between the cumulative effects of ehALT and the risk of new-onset MAFLD.RESULTS A total of 83.13%of participants with MAFLD had normal ALT levels.The incidence rate of MAFLD showed a linear increasing trend in the cumulative ehALT group.Compared with those in the low-normal ALT group,the multivariate adjusted hazard ratios of the equally and unequally weighted cumulative effects of ehALT were 1.651[95%confidence interval(CI):1.199-2.273]and 1.535(95%CI:1.119-2.106)in the third quartile and 1.616(95%CI:1.162-2.246)and 1.580(95%CI:1.155-2.162)in the fourth quartile,respectively.CONCLUSION Most participants with MAFLD had normal ALT levels.Long-term high-normal ALT levels were associated with a cumulative increased risk of new-onset MAFLD. 展开更多
关键词 Metabolic dysfunction-associated fatty liver disease High-normal alanine aminotransferase level cumulative effect Cox proportional hazards regression Cohort study
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Study on cumulative effects of biological craniocerebral trauma under repeated blast
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作者 Xingyuan Huang Bingchen Xia +3 位作者 Lijun Chang Zhikang Liao Hui Zhao Zhihua Cai 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2024年第3期174-183,共10页
Repeated blast impacts on personnel in explosive environments can exacerbate craniocerebral trauma.Most existing studies focus on the injury effects of a single blast,lacking in-depth analysis on the injury effects an... Repeated blast impacts on personnel in explosive environments can exacerbate craniocerebral trauma.Most existing studies focus on the injury effects of a single blast,lacking in-depth analysis on the injury effects and cumulative effects of repeated blasts.Therefore,rats were used as the experimental samples to suffer from explosion blasts with different peak air overpressures(167 kPa~482 kPa)and varying number of repeated blasts.The cumulative effect of craniocerebral trauma was most pronounced for moderate repeated blast,showing approximately 95%increase of trauma severity with penta blast,and an approximately 85%increase of trauma severity with penta minor blast.The cumulative effect of craniocerebral trauma from severe,repeated blast has a smaller rate of change compared to the other two conditions.The severity of trauma from penta blast increased by approximately 69%compared to a single blast.Comprehensive physiological,pathological and biochemical analysis show that the degree of neurological trauma caused by repeated blasts is higher than that of single blasts,and the pathological trauma to brain tissue is more extensive and severe.The trauma degree remains unchanged after double blast,increases by one grade after triple or quadruple blast,and increases by two grades after penta blast. 展开更多
关键词 Repeated blast Craniocerebral trauma Trauma severity grade cumulative effects
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Correlation between the cumulative analgesic effect of electroacupuncture intervention and synaptic plasticity of hypothalamic paraventricular nucleus neurons in rats with sciatica 被引量:6
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作者 Qiuling Xu Tao Liu +4 位作者 Shuping Chen Yonghui Gao Junying Wang Lina Qiao Junling Liu 《Neural Regeneration Research》 SCIE CAS CSCD 2013年第3期218-225,共8页
In the present study, a rat model of chronic neuropathic pain was established by ligation of the sciatic nerve and a model of learning and memory impairment was established by ovariectomy to investigate the analgesic ... In the present study, a rat model of chronic neuropathic pain was established by ligation of the sciatic nerve and a model of learning and memory impairment was established by ovariectomy to investigate the analgesic effect of repeated electroacupuncture stimulation at bilateral Zusanfi (ST36) and Yanglingquan (GB34). In addition, associated synaptic changes in neurons in the paraventricular nucleus of the hypothalamus were examined. Results indicate that the thermal pain threshold (paw withdrawal latency) was significantly increased in rats subjected to 2-week electroacupuncture intervention compared with 2-day electroacupuncture, but the analgesic effect was weakened remarkably in ovariectomized rats with chronic constrictive injury. 2-week electroacupuncture intervention substantially reversed the chronic constrictive injury-induced increase in the synaptic cleft width and thinning of the postsynaptic density. These findings indicate that repeated electroacupuncture at bilateral Zusanfi and Yanglingquan has a cumulative analgesic effect and can effectively relieve chronic neuropathic pain by remodeling the synaptic structure of the hypothalamic paraventricular nucleus. 展开更多
关键词 neural regeneration acupuncture and moxibustion Chronic neuropathic pain electroacupuncture acupuncture analgesia cumulative effect synaptic plasticity HYPOTHALAMUS learning and memory NEUROBIOLOGY grants-supported paper photographs-containing paper neuroregeneration
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Seasonal Cumulative Effect of Ural Blocking Episodes on the Frequent Cold events in China during the Early Winter of 2020/21 被引量:10
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作者 Yao YAO Wenqi ZHANG +2 位作者 Dehai LUO Linhao ZHONG Lin PEI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2022年第4期609-624,共16页
Starting in mid-November,China was hit by several cold events during the early winter of 2020/21.The lowest temperature observed at Beijing station on 7 January reached−19.6°C.In this paper,we show that the outbr... Starting in mid-November,China was hit by several cold events during the early winter of 2020/21.The lowest temperature observed at Beijing station on 7 January reached−19.6°C.In this paper,we show that the outbreak of the record-breaking extreme cold event can be attributed to a huge merging Ural blocking(UB)ridge over the Eurasian region.The sea-ice cover in the Kara and East Siberia Seas(KESS)in autumn was at its lowest value since 1979,which could have served as a precursor signal.Further analysis shows that several successive UB episodes occurred from 1 September 2020 to 10 January 2021.The persistent UB that occurred in late September/early October 2020 may have made an important contribution to the October historical minimum of sea ice in the KESS region.Our results also show that,after each UB episode in winter,significant upward propagation of wave activity occurred around 60°E,which resulted in weakening the stratospheric vortex.Meanwhile,each UB episode also caused a significant reduction in sea-ice extent in KESS and a significant weakening of the westerly jet in mid-high-latitude Eurasia.Results suggest that the Arctic vortex,which is supposed to enhance seasonally,became weaker and more unstable than the climatic mean under the seasonal cumulative effects of UB episodes,KESS warming,and long-lasting negative-phase North Atlantic Oscillation(NAO-).Those seasonal cumulative effects,combined with the impact of La Niña winter,led to the frequent occurrence of extreme cold events. 展开更多
关键词 extreme cold events Ural blocking Arctic sea ice Arctic vortex cumulative effect
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The cumulative analgesic effect of repeated electroacupuncture involves synaptic remodeling in the hippocampal CA3 region 被引量:5
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作者 Qiulinq Xu Tao Liu +4 位作者 Shuping Chen Yonghui Gao Junying Wang Lina Qiao Junling Liu 《Neural Regeneration Research》 SCIE CAS CSCD 2012年第18期1378-1385,共8页
In the present study, we examined the analgesic effect of repeated electroacupuncture at bilateral Zusanfi (ST36) and Yanglingquan (GB34) once a day for 14 consecutive days in a rat model of chronic sciatic nerve ... In the present study, we examined the analgesic effect of repeated electroacupuncture at bilateral Zusanfi (ST36) and Yanglingquan (GB34) once a day for 14 consecutive days in a rat model of chronic sciatic nerve constriction injury-induced neuropathic pain. In addition, concomitant changes in calcium/calmodulin-dependent protein kinase II expression and synaptic ultrastructure of neurons in the hippocampal CA3 region were examined. The thermal pain threshold (paw withdrawal latency) was increased significantly in both groups at 2 weeks after electroacupuncture intervention compared with 2 days of electroacupuncture. In ovariectomized rats with chronic constriction injury, the analgesic effect was significantly reduced. Electroacupuncture for 2 weeks significantly diminished the injury-induced increase in synaptJc cleft width and thinning of the postsynaptJc density, and it significantly suppressed the down-regulation of intracellular calcium/ calmodulin-dependent protein kinase II expression in the hippocampal CA3 region. Repeated electroacupuncture intervention had a cumulative analgesic effect on injury-induced neuropathic pain reactions, and it led to synaptic remodeling of hippocampal neurons and upregulated calcium/calmodulin-dependent protein kJnase II expression in the hippocampal CA3 region. 展开更多
关键词 chronic neuropathic pain acupuncture analgesia cumulative effect synaptic plasticity hippocampal CA3 region calcium/calmodulin-dependent protein kinase II NEUROBIOLOGY ELECTROACUPUNCTURE neural regeneration
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Enhancement effect of cumulative second-harmonic generation by closed propagation feature of circumferential guided waves 被引量:1
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作者 Guang-Jian Gao Ming-Xi Deng +1 位作者 Ning Hu Yan-Xun Xiang 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第2期301-308,共8页
On the basis of second-order perturbation approximate and modal expansion approach,we investigate the enhancement effect of cumulative second-harmonic generation(SHG)of circumferential guided waves(CGWs)in a circular ... On the basis of second-order perturbation approximate and modal expansion approach,we investigate the enhancement effect of cumulative second-harmonic generation(SHG)of circumferential guided waves(CGWs)in a circular tube,which is inherently induced by the closed propagation feature of CGWs.An appropriate mode pair of primary-and double-frequency CGWs satisfying the phase velocity matching and nonzero energy flux is selected to ensure that the second harmonic generated by primary CGW propagation can accumulate along the circumference.Using a coherent superposition of multi-waves,a model of unidirectional CGW propagation is established for analyzing the enhancement effect of cumulative SHG of primary CGW mode selected.The theoretical analyses and numerical simulations performed directly demonstrate that the second harmonic generated does have a cumulative effect along the circumferential direction and the closed propagation feature of CGWs does enhance the magnitude of cumulative second harmonic generated.Potential applications of the enhancement effect of cumulative SHG of CGWs are considered and discussed.The theoretical analysis and numerical simulation perspective presented here yield an insight previously unavailable into the physical mechanism of the enhancement effect of cumulative SHG by closed propagation feature of CGWs in a circular tube. 展开更多
关键词 CIRCUMFERENTIAL guided wave second-harmonic generation(SHG) enhancement effect of cumulative SHG CLOSED PROPAGATION FEATURE
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The Impact of Meteorological Factors on the Short-term Cumulative Effect of Air Particulate in Tianjin 被引量:1
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作者 Wang Wei Liu Lili Wang Yan 《Meteorological and Environmental Research》 CAS 2019年第2期27-32,40,共7页
In order to reveal the rapid increase mechanism of particulate concentration in short time,a notion of short-term cumulative effect of air particulate is defined as the significant increase of pollutant concentration ... In order to reveal the rapid increase mechanism of particulate concentration in short time,a notion of short-term cumulative effect of air particulate is defined as the significant increase of pollutant concentration in a short time under the condition of breeze,stable weather and constant emission caused by human being's activities. Subsequently,an index of short-term cumulative effect is established with air diffusive equation,and then the macro-scale meteorological situation and micro-scale factors of forming the short-term cumulative effect are discussed with the observation data. The macro-scale meteorological variables contain upper-level weather situations and surface weather situations. The micro-scale factors mainly include the boundary-layer height and boundary-layer stability. The analyses show that boundary-layer factors and weather variables have a significant influence on the short-term cumulative effect. The notion of short-term cumulative effect will play an important role in interpreting the severe pollution weather. 展开更多
关键词 AIR PARTICULATE SHORT-TERM cumulative effect METEOROLOGICAL factor cumulative index
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Blasting cumulative damage effects of underground engineering rock mass based on sonic wave measurement 被引量:5
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作者 闫长斌 《Journal of Central South University of Technology》 EI 2007年第2期230-235,共6页
The principle of sonic wave measurement was introduced, and cumulative damage effects of underground engineering rock mass under blasting load were studied by in situ test, using RSM-SY5 intelligent sonic wave apparat... The principle of sonic wave measurement was introduced, and cumulative damage effects of underground engineering rock mass under blasting load were studied by in situ test, using RSM-SY5 intelligent sonic wave apparatus. The blasting test was carried out for ten times at some tunnels of Changba Lead-Zinc Mine. The damage depth of surrounding rock caused by old blasting excavation (0.8-1.2 m) was confirmed. The relation between the cumulative damage degree and blast times was obtained. The results show that the sonic velocity decreases gradually with increasing blast times, hut the damage degree (D) increases. The damage cumulative law is non-linear. The damage degree caused by blast decreases with increasing distance, and damage effects become indistinct. The blasting damage of rock mass is anisotropic. The damage degree of rock mass within charging range is maximal. And the more the charge is, the more severe the damage degree of rock mass is. The test results provide references for researches of mechanical parameters of rock mass and dynamic stability analysis of underground chambers. 展开更多
关键词 sonic wave measurement cumulative damage effects damage degree blasting load surrounding rock of underground engineering RSM-SY5 intelligent sonic wave apparatus
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Quantitative Evaluation of Ecological Cumulative Effects and Zoning Regulations for Prefectural Mining Units in China 被引量:1
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作者 MA Li KANG Lei +1 位作者 TIAN Huazheng XU Die 《Chinese Geographical Science》 SCIE CSCD 2022年第1期49-63,共15页
Although the development of energy and mineral resources strongly supports China’s rapid industrialization and urbanization,it has led to a series of ecological and environmental problems.Strengthening the spatial re... Although the development of energy and mineral resources strongly supports China’s rapid industrialization and urbanization,it has led to a series of ecological and environmental problems.Strengthening the spatial regulation considering the ecological and environmental protection on energy and mineral resource development areas is an important aspect of realizing China’s sustainable development.In this study,we mapped,categorized,and analyzed the ecological cumulative effects of the Chinese 134 prefectural mining units based on the pressure-state-response model,which is demonstrated as impact of mining activities on ecological environment,ecological environmental fragility,and ecological function.This investigation developed a stress zoning typology of the mining units based on scores of three dimensions of the ecological cumulative effects and classified 134 prefectural mining units into eight types of stress zones.A series of regulation and policy suggestions have been proposed to different types of zones from three aspects:space control,intensity control,and development mode control.The application of this evaluation and spatial zoning system will contribute to the refined spatial management of China’s mining areas. 展开更多
关键词 ecological cumulative effects quantitative evaluation pressure-state-response model ZONING
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Cumulative impact of dam constructions on streamflow and sediment regime in lower reaches of the Jinsha River, China 被引量:7
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作者 HUANG Xiao-rong GAO Lin-yun +1 位作者 YANG Peng-peng XI Yuan-yuan 《Journal of Mountain Science》 SCIE CSCD 2018年第12期2752-2765,共14页
The cumulative effect of cascade hydropower stations on river ecological environment has been widely concerned because of the significant streamflow hydrology change induced by dam constructions. The characteristics o... The cumulative effect of cascade hydropower stations on river ecological environment has been widely concerned because of the significant streamflow hydrology change induced by dam constructions. The characteristics of the change in the lower reaches of the Jinsha River, China are analyzed based on long-term(1952–2015) hydrological and sedimentological data. The averaging coefficient, reservoir regulation coefficient(RRC), incoming sediment coefficient(ISC), and sediment transport modulus(STM), which reflect the variation of streamflow and sediment regimes, are defined and calculated. The results show that the construction and regulation of reservoirs reduces flow in flood season, increases flow in dry season, significantly altering the monthly discharge regimes. These alterations also led directly to changes in the timing of extreme flows at Pingshan Station. The monthly flow records at the basin outlet are reconstructed using stepwise regression, to reduce reservoir impacts. Comparisons of observed and reconstructed monthly flows demonstrate that the previous studies overestimated the cumulative effects of cascade reservoirs on flow processes. Furthermore, this study clearly illustrates that the reduction in sediment trapping and sediment transportation capacity together lead to the sharp reduction in annual sediment yield at the Pingshan Station. The earlier constructed reservoirs have more obvious effects on the ISC and STM than the more recent reservoirs and the effect of sediment trapping is related to reservoir location, on the main stream versus tributaries. 展开更多
关键词 CASCADE RESERVOIRS cumulative effect HYDROLOGICAL REGIME Sediment load Jinsha River
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Cumulative second-harmonic generation of Lamb waves propagating in a two-layered solid plate 被引量:2
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作者 项延训 邓明晰 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第11期4232-4241,共10页
The physical process of cumulative second-harmonic generation of Lamb waves propagating in a two-layered solid plate is presented by using the second-order perturbation and the technique of nonlinear reflection of aco... The physical process of cumulative second-harmonic generation of Lamb waves propagating in a two-layered solid plate is presented by using the second-order perturbation and the technique of nonlinear reflection of acoustic waves at an interface. In general, the cumulative second-harmonic generation of a dispersive guided wave propagation does not occur. However, the present paper shows that the second-harmonic of Lamb wave propagation arising from the nonlinear interaction of the partial bulk acoustic waves and the restriction of the three boundaries of the solid plates does have a cumulative growth effect if some conditions are satisfied. Through boundary condition and initial condition of excitation, the analytical expression of cumulative second-harmonic of Lamb waves propagation is determined. Numerical results show the cumulative effect of Lamb waves on second-harmonic field patterns. 展开更多
关键词 Lamb waves second harmonics cumulative effect layered plates
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Utilizing a new soil effective temperature scheme and archived satellite microwave brightness temperature data to estimate surface soil moisture in the Nagqu region, Tibetan Plateau of China 被引量:1
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作者 TIAN Hui Mudassar IQBAL 《Journal of Arid Land》 SCIE CSCD 2018年第1期84-100,共17页
Since the early 2000s, many satellite passive microwave brightness temperature (BT) archives, such as the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) BTs, have become the useful ... Since the early 2000s, many satellite passive microwave brightness temperature (BT) archives, such as the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) BTs, have become the useful resources for assessing the changes in the surface and deep soil moistures over both arid and semi-arid regions. In this study, we used a new soil effective temperature (T scheme and the archived AMSR-E BTs to estimate surface soil moisture (SM) over the Nagqu region in the central Tibetan Plateau, China. The surface and deep soil temperatures required for the calculation of regional-scale T were obtained from outputs of the Community Land Model version 4.5 (CLM4.5). In situ SM measurements at the CEOP-CAMP/Tibet (Coordinated Enhanced Observing Period Asia-Australia Monsoon Project on the Tibetan Plateau) experimental sites were used to validate the AMSR-E-based SM estimations at regional and single-site scales. Furthermore, the spatial distribution of monthly mean surface SM over the Nagqu region was obtained from 16 daytime AMSR-E BT observations in July 2004 over the Nagqu region. Results revealed that the AMSR-E-based surface SM estimations agreed well with the in situ-based surface SM measurements, with the root mean square error (RMSE) ranging from 0.042 to 0.066 m3/m3 and the coefficient of determination (R2) ranging from 0.71 to 0.92 during the nighttime and daytime. The regional surface soil water state map showed a clear spatial pattern related to the terrain. It indicated that the lower surface SM values occurred in the mountainous areas of the northern, mid-western and southeastern parts of Nagqu region, while the higher surface SM values appeared in the low elevation areas such as the Tongtian River Basin, Namco Lake and bog meadows in the central part of Nagqu region. Our analysis also showed that the new T^scheme does not require special fitting parameters or additional assumptions, which simplifies the data requirements for regional-scale applications. This scheme combined with the archived satellite passive microwave BT observations can be used to estimate the historical surface SM for hydrological process studies over the Tibetan Plateau regions. 展开更多
关键词 soil effective temperature archived AMSR-E brightness temperature CLM4.5 soil temperature output cumulative Distribution Function (CDF) matching surface soil moisture Tibetan Plateau
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Shaking table test and cumulative deformation evaluation analysis of a tunnel across the hauling sliding surface 被引量:1
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作者 Lifang Pai Honggang Wu Xu Wang 《Deep Underground Science and Engineering》 2023年第4期371-393,共23页
To explore the cumulative deformation effect of the dynamic response of a tunnel crossing the hauling sliding surface under earthquakes,the shaking table test was conducted in this study.Combined with the numerical ca... To explore the cumulative deformation effect of the dynamic response of a tunnel crossing the hauling sliding surface under earthquakes,the shaking table test was conducted in this study.Combined with the numerical calculations,this study proposed magnification of the Arias intensity(MIa)to characterize the overall local deformation damage of the tunnel lining in terms of the deformation characteristics,frequency domain,and energy.Using the time‐domain analysis method,the plastic effect coefficient(PEC)was proposed to characterize the degree of plastic deformation,and the applicability of the seismic cumulative failure effect(SCFE)was discussed.The results show that the low‐frequency component(f1 and f2≤10 Hz)and the high‐frequency component(f3 and f4>10 Hz)acceleration mainly cause global and local deformation of the tunnel lining.The local deformation caused by the high‐frequency wave has an important effect on the seismic damage of the lining.The physical meaning of PEC is more clearly defined than that of the residual strain,and the SCFE of the tunnel lining can also be defined.The SCFE of the tunnel lining includes the elastic deformation effect stage(<0.15g),the elastic–plastic deformation effect stage(0.15g–0.30g),and the plastic deformation effect stage(0.30g–0.40g).This study can provide valuable theoretical and technical support for the construction of traffic tunnels in high‐intensity earthquake areas. 展开更多
关键词 magnification of Arias intensity plastic effect coefficient seismic action seismic cumulative failure effect shaking table test tunnel engineering
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Cumulative radiation exposure from diagnostic imaging in intensive care unit patients
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作者 Fiachra Moloney Daniel Fama +7 位作者 Maria Twomey Ruth O'Leary Conor Houlihane Kevin P Murphy Siobhan B O'Neill Owen J O'Connor Dorothy Breen Michael M Maher 《World Journal of Radiology》 CAS 2016年第4期419-427,共9页
AIM:To quantify cumulative effective dose of intensive care unit(ICU)patients attributable to diagnostic imaging.METHODS:This was a prospective,interdisciplinary study conducted in the ICU of a large tertiary referral... AIM:To quantify cumulative effective dose of intensive care unit(ICU)patients attributable to diagnostic imaging.METHODS:This was a prospective,interdisciplinary study conducted in the ICU of a large tertiary referral and level 1 trauma center.Demographic and clinical data including age,gender,date of ICU admission,primary reason for ICU admission,APACHE Ⅱ score,length of stay,number of days intubated,date of death or discharge,and re-admission data was collected on all patients admitted over a 1-year period.The overall radiation exposure was quantified by the cumulative effective radiation dose(CED)in millisieverts(mS v)and calculated using reference effective doses published by the United Kingdom National Radiation Protection Board.Pediatric patients were selected for subgroupanalysis.RESULTS:A total of 2737 studies were performedin 421 patients.The total CED was 1704 m Sv with a median CED of 1.5 mS v(IQR 0.04-6.6 mS v).Total CED in pediatric patients was 74.6 mS v with a median CED of 0.07 mS v(IQR 0.01-4.7 mS v).Chest radiography was the most commonly performed examination accounting for 83% of all studies but only 2.7% of total CED.Computed tomography(CT)accounted for 16% of all studies performed and contributed 97% of total CED.Trauma patients received a statistically significant higher dose [median CED 7.7 mS v(IQR 3.5-13.8 mS v)] than medical [median CED 1.4 m Sv(IQR 0.05-5.4 m Sv)] and surgical [median CED 1.6 mS v(IQR 0.04-7.5 mS v)] patients.Length of stay in ICU [OR = 1.12(95%CI:1.079-1.157)] was identified as an independent predictor of receiving a CED greater than 15 mS v.CONCLUSION:Trauma patients and patients with extended ICU admission times are at increased risk of higher CEDs.CED should be minimized where feasible,especially in young patients. 展开更多
关键词 cumulative effective DOSE PEDIATRIC PATIENTS COMPUTED tomography Radiation DOSE INTENSIVE care unit
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短路累积效应对绕组磁-力特征影响试验研究
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作者 律方成 汪鑫宇 +2 位作者 王平 耿江海 高树国 《华北电力大学学报(自然科学版)》 北大核心 2025年第1期95-102,共8页
为探究变压器绕组在多次短路冲击下逐渐劣化过程,开展了110 kV真型变压器短时多次短路冲击试验,测量了短路试验过程中的漏磁、振动加速度实时波形以及试验后绕组轴向压力稳态值及电抗变化率,提取了漏磁、振动频谱特征,获得了各项物理量... 为探究变压器绕组在多次短路冲击下逐渐劣化过程,开展了110 kV真型变压器短时多次短路冲击试验,测量了短路试验过程中的漏磁、振动加速度实时波形以及试验后绕组轴向压力稳态值及电抗变化率,提取了漏磁、振动频谱特征,获得了各项物理量随短路电流强度、短路次数下的变化趋势。结果表明:多次短路冲击会使变压器绕组产生累积效应,累积效应影响程度与冲击次数和冲击强度有关;在累积效应作用下,磁场信号会由于绕组形变程度低或测点距离形变处较远而变化不明显,但振动加速度的频谱熵、Pearson相关系数的变化可以良好反映绕组的机械状态改变。因此监测变压器振动信号并分析其频谱是评估短路累积效应影响、绕组形变诊断的可靠手段。 展开更多
关键词 变压器绕组 累积效应 短时多次短路 特征评估
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金沙江下游梯级水电开发引起的水温累积效应分析
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作者 胡光洋 杨中华 +3 位作者 白凤朋 任玉峰 马一鸣 李文晖 《湖泊科学》 EI CAS 北大核心 2025年第1期293-303,共11页
金沙江下游梯级水库群在流域水温调控中扮演着关键角色,然而,对于梯级水库联合运行对下泄水温影响的认识仍然不够充分。本研究基于金沙江下游龙街(三)、乌东德、白鹤滩、溪洛渡、向家坝水文站长序列实测水温数据,从水温基线偏移、相位... 金沙江下游梯级水库群在流域水温调控中扮演着关键角色,然而,对于梯级水库联合运行对下泄水温影响的认识仍然不够充分。本研究基于金沙江下游龙街(三)、乌东德、白鹤滩、溪洛渡、向家坝水文站长序列实测水温数据,从水温基线偏移、相位偏移和极值变幅3方面定量分析了金沙江下游梯级水库在不同运行阶段对沿程水温的累积影响。结果表明:(1)金沙江下游梯级水库建成后“热源效应”显著,乌东德、白鹤滩、溪洛渡、向家坝年均下泄水温逐年升高,年内水温变幅较天然水温最大减小4.1、2.4、1.6、3.2℃,沿程增温率由天然状态的0.348℃/100 km降至现阶段的0.256℃/100 km。(2)随着建库时间的增长,金沙江下游梯级水库水温累积程度逐渐增强,变化速度趋缓,至2022年四级水电全部投产运行后,乌东德、白鹤滩、溪洛渡、向家坝下泄水温比天然水温分别滞后19、58、49、65 d。(3)金沙江下游4个水库中白鹤滩对水温的影响最大,且不同类型水库在水温传递和累积方面呈现出独特的规律,混合型水库作为“龙头”水库时表现为正效应,稳定分层型水库表现为正效应,不稳定分层型和过渡型水库在不同阶段分别表现出正效应和负效应。本研究对于优化水资源管理、提高水电效益具有指导作用,同时为维护下游生态系统的健康提供了科学依据。 展开更多
关键词 金沙江下游 梯级水库 水温 累积效应
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基于单风电场功率波形幅-时特性的风电场群功率波动幅度演化建模与机理分析
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作者 付子恒 穆钢 +2 位作者 武方泽 杨茂 严干贵 《中国电机工程学报》 北大核心 2025年第1期124-137,I0010,共15页
大规模风电场群的功率波形是由场群内所有风电场功率波形累加而成。风电场群区域内风速时空分布的差异和风电场空间位置的分散导致各单风电场功率波形时序上的差异性,从而使场群功率的最大相对波动幅度低于单场功率的最大相对波动幅度,... 大规模风电场群的功率波形是由场群内所有风电场功率波形累加而成。风电场群区域内风速时空分布的差异和风电场空间位置的分散导致各单风电场功率波形时序上的差异性,从而使场群功率的最大相对波动幅度低于单场功率的最大相对波动幅度,称为风电场群功率的汇聚效应。为了揭示汇聚效应的机理及其时空影响因素,该文根据各风电场功率波形具有相关性的特点,建立描述风电场群区域主要风速时空变化特征的一维风速行波函数,构建反映单风电场到风电场群功率波形演化关系的风电场群功率汇聚模型;基于离散小波变换构建反映风电功率波形多尺度变化特征的风电功率波形幅-时关联特性;深入分析风电场功率波形幅-时关联特性与风电场空间尺度的关联关系,建立基于单风电场功率波形幅-时关联特性的风电场群功率波动幅度评价方法,揭示单风电场功率波形特质及风电场空间间距影响风电场群功率波动幅度的机理。通过两个风电场群的实例验证所提模型和分析方法的有效性。 展开更多
关键词 风电场群 风电功率波形 汇聚效应 幅-时关联特性 风电功率波动幅度
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Characterization of combined blast-and fragments-induced synergetic damage in polyurea coated liquid-filled container
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作者 Chen Tao Chong Ji +3 位作者 Xin Wang Juan Gu Yuting Wang Changxiao Zhao 《Defence Technology(防务技术)》 2025年第1期201-224,共24页
Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves a... Liquid-filled containers(LFC)are widely used to store and transport petroleum,chemical reagents,and other resources.As an important target of military strikes and terrorist bombings,LFC are vulnerable to blast waves and fragments.To explore the protective effect of polyurea elastomer on LFC,the damage characteristics of polyurea coated liquid-filled container(PLFC)under the combined loading of blast shock wave and fragments were studied experimentally.The microstructure of the polyurea layer was observed by scanning electron microscopy,and the fracture and self-healing phenomena were analyzed.The simulation approach was used to explain the combined blast-and fragments-induced on the PLFC in detail.Finally,the effects of shock wave and fragment alone and in combination on the damage of PLFC were comprehensively compared.Results showed that the polyurea reduces the perforation rate of the fragment to the LFC,and the self-healing phenomenon could also reduce the liquid loss rate inside the container.The polyurea reduces the degree of depression in the center of the LFC,resulting in a decrease in the distance between adjacent fragments penetrating the LFC,and an increase in the probability of transfixion and fracture between holes.Under the close-in blast,the detonation shock wave reached the LFC before the fragment.Polyurea does not all have an enhanced effect on the protection of LFC.The presence of internal water enhances the anti-blast performance of the container,and the hydrodynamic ram(HRAM)formed by the fragment impacting the water aggravated the plastic deformation of the container.The combined action has an enhancement effect on the deformation of the LFC.The depth of the container depression was 27%higher than that of the blast shock wave alone;thus,it cannot be simply summarized as linear superposition. 展开更多
关键词 POLYUREA Prefabricated fragment Liquid-filled container Hydrodynamic ram cumulative effect
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对称双线性起爆下爆轰波的轴向传播特性
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作者 李昱锦 缪玉松 +4 位作者 李斌 黄飞飞 葛帅 杨涛 吴佳怡 《爆破器材》 北大核心 2025年第1期7-13,共7页
利用爆轰波的碰撞可在药包中产生聚能效应,从而改善爆轰效果。为分析爆轰波碰撞聚能特性,首先,基于爆轰波碰撞理论,推导了对称双线性起爆下条形药包中爆轰波的轴向传播速度;其次,利用LS-DYNA有限元软件分析了爆轰波的轴向传播特性;最后... 利用爆轰波的碰撞可在药包中产生聚能效应,从而改善爆轰效果。为分析爆轰波碰撞聚能特性,首先,基于爆轰波碰撞理论,推导了对称双线性起爆下条形药包中爆轰波的轴向传播速度;其次,利用LS-DYNA有限元软件分析了爆轰波的轴向传播特性;最后,利用连续压导探针对药包中心轴线处的爆速进行测定,并对爆轰波在轴向达到稳定时的爆压进行分析。结果表明:爆轰波在轴向的传播达到稳定后,马赫波传播速度接近导爆索的爆速,马赫杆占据整个药包直径,并以近似平面波的形式稳定传播。数值计算与现场实验得到的爆轰参数相近,均与导爆索的设定值相当,且爆速比铵油炸药的设定爆速高出60%左右,爆压高出160%左右。理论分析、数值计算及现场实验得到的爆轰参数互相吻合。研究结果表明,对称双线性起爆技术能显著提高炸药的爆轰性能,实现爆轰波的聚能效应。 展开更多
关键词 对称双线性起爆 连续压导探针 聚能效应 爆速 爆压
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