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151.
利用多层砌体房屋震害预测专家系统,对山东潍坊地区182栋多层砖房逐栋进行了单体房屋的震害预测,在此基础上,统计分析了该地区多层砖房的地震易损性特征,并进行了初步震害预测研究,给出了该类房屋的易损性矩阵,各破坏等级的损失参数矩阵和对应不同地震烈度的相对损失预测,为进一步开展震害预测和采取地对性的防震减灾对策提供了科学依据。 相似文献
152.
This study addresses a need to document changes in streamflow and base flow (groundwater discharge to streams) in Hawai‘i during the past century. Statistically significant long‐term (1913–2008) downward trends were detected (using the nonparametric Mann–Kendall test) in low‐streamflow and base‐flow records. These long‐term downward trends are likely related to a statistically significant downward shift around 1943 detected (using the nonparametric Pettitt test) in index records of streamflow and base flow. The downward shift corresponds to a decrease of 22% in median streamflow and a decrease of 23% in median base flow between the periods 1913–1943 and 1943–2008. The shift coincides with other local and regional factors, including a change from a positive to a negative phase in the Pacific Decadal Oscillation, shifts in the direction of the trade winds over Hawai‘i, and a reforestation programme. The detected shift and long‐term trends reflect region‐wide changes in climatic and land‐cover factors. A weak pattern of downward trends in base flows during the period 1943–2008 may indicate a continued decrease in base flows after the 1943 shift. Downward trends were detected more commonly in base‐flow records than in high‐streamflow, peak‐flow, and rainfall records. The decrease in base flow is likely related to a decrease in groundwater storage and recharge and therefore is a valuable indicator of decreasing water availability and watershed vulnerability to hydrologic changes. Whether the downward trends will continue is largely uncertain given the uncertainty in climate‐change projections and watershed responses to changes. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
153.
154.
栉孔扇贝不同种群杂交效果的研究 Ⅱ.中国种群和俄罗斯种群及其杂种F1中期生长发育 总被引:1,自引:1,他引:1
在对栉孔扇贝中国养殖种群(CC)、中国野生种群(CW)和俄罗斯种群(RW)及其3 种杂交种群早期(2,3,4月龄)生长发育研究的基础上进行了各种群的中期(6,8,10,12月龄)生长发育测定比较研究,结果表明,3个亲本群体各个性状的中期生长性能表现以中国养殖种群最好;3个杂交组合的杂种群体各个性状的中期生长性能均高于纯种亲本种群,杂种优势均较大,其范围在3%~52%,以CC♀×RW♂杂交效果最好;壳长、壳宽、壳高、活体重在4个生长发育指标中期的4 个阶段均表现出不同程度的杂种优势,杂种优势在性状间存在明显差别,体重的杂种优势远大于壳宽、壳长和壳高的,变化趋势为体重大于壳宽,壳宽大于壳长,壳长大于壳高;季节性变化因素对栉孔扇贝各个性状的生长速度影响非常大,6~8月龄处于冬季最寒冷的时间(11月份至翌年3月份),扇贝越冬期间仅能维持生命,生长率接近于0,温暖季节如6月龄(11月)以前和8月龄(3月份)以后各性状的生长速度提高幅度很大. 相似文献
155.
采集采自山东某养殖场的栉孔扇贝(Chlamys farreri)健康贝和病贝的血淋巴,测定其血浆蛋白浓度、血浆蛋白图谱和相对分子质量,以及血浆抗菌活性、凝集素活性等几种重要的体液免疫因素,研究环境胁迫对血浆蛋白及其抗菌活性的影响。结果表明:栉孔扇贝(C.farreri)血浆蛋白质量浓度约1 260~1 650μg/mL;血浆蛋白SDS-PAGE图谱显示3条蛋白带,相对分子质量分别为34 000、25 000和14 000;健康贝血浆抗菌活性指数BI为0.34,病贝BI为0.21;凝集素活力水平为1.602~2.204。氨氮胁迫下血浆蛋白浓度下降约780μg/mL,凝集素活力下降为1.301;高温胁迫下血浆蛋白质量浓度下降约为900μg/mL,凝集素活力为1.903;高盐胁迫下血浆蛋白浓度下降约为990μg/mL,凝集素活力为2.204。 相似文献
156.
Protective Effect of Topically Applied Polypeptide from Chlamys farreri Against Ultraviolet Radiation-Induced Chronic Skin Damage in Guinea Pig 总被引:2,自引:0,他引:2
INTRODUCTIONSolarultraviolet(UV)radiationisknowntobeamajoretiologicalriskofphotoaging.AsUVC(2 0 0nm -2 90nm)isabsorbedentirelybythestratosphericozonelayer,sunlightontheearthsur faceiscomposedofUVA (3 2 0nm -4 0 0nm)andUVB (2 90nm -3 2 0nm)only.UVAradiationenergyaccountsformorethan 90 %ofsolarUV ;andpenetratesthebasallayerofepidermismoreefficientlythanUVB (Brulsetal.,1984) .However,atsimilardosages,UVBismuchmoremuta genicthanUVA (Drobetskyetal.,1995) .Furthermore ,humanskinisexp… 相似文献
157.
Wendy K. Stovall B. F. Houghton A. J. L. Harris D. A. Swanson 《Bulletin of Volcanology》2009,71(3):313-318
Lava lakes are found at basaltic volcanoes on Earth and other planetary bodies. Density-driven crustal foundering leading
to surface renewal occurs repeatedly throughout the life of a lava lake. This process has been observed and described in a
qualitative sense, but due to dangerous conditions, no data has been acquired to evaluate the densities of the units involved.
Kīlauea Iki pit crater in Hawai`i houses a lava lake erupted during a 2 month period in 1959. Part of the surface of the Kīlauea
Iki lake now preserves the frozen record of a final, incomplete, crustal-overturn cycle. We mapped this region and sampled
portions of the foundering crust, as well as overriding and underlying lava, to constrain the density of the units involved
in the overturn process. Overturn is driven by the advance of a flow front of fresh, low-density lava over an older, higher
density surface crust. The advance of the front causes the older crust to break up, founder, and dive downwards into the lake
to expose new, hot, low-density lava. We find density differences of 200 to 740 kg/m3 between the foundering crust and over-riding and under-lying lava respectively. In this case, crustal overturn is driven
by large density differences between the foundering and resurfacing units. These differences lead, inevitably, to frequent
crustal renewal: simple density differences between the surface crust and underlying lake lava make the upper layers of the
lake highly unstable.
Work originally presented at the American Geophysical Union Fall Meeting in San Francisco, California on December 11, 2007. 相似文献
158.
~~The Polypeptide in Chlamys farreri can protect human dermal fibroblasts from ultraviolet B damage@张玉江$Qingdao University, Medical College,Qingdao Shandong 266021,China
@战松梅$Qingdao University, Medical College,Qingdao Shandong 266021,China
@曹鹏利$Qingdao University, Medical College,Qingdao Shandong 266021,China
@刘宁$Qingdao University, Medical College,Qingdao Shandong 266021,China
@陈雪红$Qingdao University, Medical College,Qingdao Shandong 266021,China
@… 相似文献
159.
目的 探索Sysmex UF-1000i尿沉渣分析仪定量检测结果中细菌和白细胞计数在诊断尿路感染中的价值,阐明标本采集送检的不同对UF-1000i诊断尿路感染的影响。方法 选取笔者医院2015年7月~2015年8月466例怀疑尿路感染的入院患者同时做细菌培养及尿常规的检验结果(A组标本),收集2016年3月下旬~4月上旬148例尿细菌培养清洁中段尿标本,接种之后立即送检尿常规检查(B组标本)。取两组标本的细菌及白细胞计数结果,以细菌培养为金标准用SPSS 18.0统计软件分别绘制ROC曲线,求出尿沉渣细菌和白细胞计数诊断尿路感染的阈值,并计算其敏感度、特异性、阳/阴性预测值、假阳性/假阴性率和准确性,比较两组标本的各项指标。结果 尿沉渣细菌与白细胞定量检测最佳阈值,A组标本分别为101.7/μl与18.8/μl,B组标本分别为98.7/μl与11.1/μl。尿沉渣细菌与白细胞ROC曲线下面积,A组标本分别为0.604与0.661,B组标本分别为0.941与0.848。对B组标本而言,细菌与白细胞联合诊断尿路感染最佳敏感度为82.4%,特异性为92.1%,阳性预测值为77.8%,阴性预测值为93.8%,假阳性率为7.9%,假阴性率为17.6%,准确度为89.9%,并可将细菌培养降低70.9%。结论 UF-1000i尿液沉渣分析仪在诊断尿路感染中有早期筛选,辅助诊断的价值。标本达到无菌采集、中段尿并在2h内送检的要求才能使UF-1000i发挥最大价值。 相似文献
160.
利用扫描电子显微镜技术对海湾扇贝、栉孔扇贝、太平洋牡蛎、菲律宾蛤仔4种滤食性养殖贝类的滤食器官鳃的形态结构进行了观察和比较。结果表明:1、4种贝类的鳃纤毛是极其发达的,鳃丝内侧分布大量的粘液细胞;2、海湾扇贝、栉孔扇贝鳃丝的侧纤毛不如太平洋牡蛎和菲律宾蛤仔的发达,太平洋牡蛎鳃丝内侧纤毛很发达;3、4种贝类鳃丝之间的距离都大于20μm,鳃丝间距排序为菲律宾蛤仔<海湾扇贝<栉孔扇贝<太平洋牡蛎。从电镜观察的结果看,贝类的取食与鳃的结构及鳃丝上纤毛的运动密切相关。 相似文献