共查询到20条相似文献,搜索用时 62 毫秒
1.
[目的]分析河西走廊东部近50年高、低温气候特征.[方法]利用河西走廊东部5个气象站 1960~2009 年高(日最高气温≥35℃)、低温(日最低气温≤-20℃)资料,运用统计学方法详细分析了高、低气温的时空分布、强度、持续性和环流形势等气候特征.[结果]河西走廊东部高温天气主要发生在东北部沙漠边缘;低温天气主要发生在海拔较高的山区和北部沙漠边缘.随着气候变暖,高温日数呈弱增加趋势,强度增强;低温日数呈明显减少趋势,强度减弱.高温天气主要出现在7、8月;低温主要出现在1、2、12月.高、低温天气具有持续性特征,强高、低温大多出现在高、低温持续时段内.高温天气出现在副热带高压控制及影响的区域内;低温天气出现在强冷空气堆积和入侵的区域内.[结论]该研究为高、低温的准确预报和预警提供了一定的理论基础. 相似文献
2.
选择 2006 年作为湖北省区域风能资源代表年,利用中尺度气象模式 MM5 和小尺度诊断模式 CALMET 组成的风能资源评估模式系统,模拟了代表年湖北省 1 km 水平分辨率下各高度层的风向风速,并以此为基础分析得到各风能资源参数,利用湖北省 4 座测风塔实测资料对模拟结果进行验证.给出了湖北省风能资源分布图,并对风能资源丰富地区进行了分区.结合 GIS 技术估算出湖北省 50 m高度层风功率密度≥250 w/m<'2>的面积为 1 664.16 km<'2>,风能资源储量为 332.8 万 kw.最后给出了湖北省风能资源开发利用的建议. 相似文献
3.
利用1973~2003年大雾气象资料,分析了连云港市沿海大雾的气候特征及大雾多发期的特征.结果表明,连云港市沿海大雾存在明显的年际和年代际变化,大雾呈现逐年增长趋势,且20世纪70年代大雾最少,90年代最多;大雾月变化呈双峰曲线,主要集中在3~6月和11月~次年1月;一天中大雾多发生20:00~次日08:00,其中以04:00~08:00发生频率最高,消散时间主要集中在12:00以前,其中以08:00~10:00最多;大雾持续的时间有长有短,大多数大雾都在8 h以内散尽消失,其中大雾持续2 h的比例最高;从连续性特征看,无论哪个多发期,持续2 d的连续性大雾最多,3 d次之;不同季节出现大雾时的风向风速也有所不同,11月~次年1月大雾时的风速90%以上均在3 m/s以下,风向以静风最多,占30.3%,其次是第3象限风向(SSW-W);而3-6月份,大雾时的风速明显偏大,且第1象限风向(NNE-E)最多,占52.2%. 相似文献
4.
[目的]研究太原盆地玉米和大豆的光合日变化以及光合光响应变化.[方法]采用Licor-6400型便携式光合测定仪进行测定,各参数使用非直角双曲线和二项式曲线拟合.[结果]玉米日变化曲线呈双峰型,pn峰值分别出现在10:00和15:00,有明显的光合午休现象.大豆日变化曲线由于天气状况的影响呈3峰型,Pn峰值分别出现在10:00、12:00和16:00,不考虑下午天气状况影响的条件下,也存在明显的光合午休现象.随着光合有效辐射强度PAR的增加,玉米和大豆的净光合速率Pn增大.当PAR达到1 900 μmol/(m2·s)时,大豆出现光抑制现象,玉米在PAR达到1 700 μmol/(m2·s)时出现光抑制现象.[结论]玉米和大豆均表现为典型的阳性植物特点,R2分别为0.958和0.932,拟合效果良好. 相似文献
5.
[目的]研究山东省霜冻的气候变化特征.[方法]以秋季或春季日最低地面温度≤0℃作为霜冻指标,利用1961~2008年山东省67个气象监测站的逐日地面最低温度资料,采用气候诊断分析方法,对山东省初、终霜日期和无霜期的变化特征进行了分析.[结果]近48年来,山东省的初、终霜日和无霜期的气候特征具有明显地域差异.初、终霜日和无霜期的极差均为标准差的3倍以上,说明初、终霜日和无霜期离散程度均较大.近48年山东省平均初霜日以1.99 d/10a的速率推迟,终霜日以1.46d/10a的速率提早,初霜日推迟幅度比终霜日提早幅度大;无霜期以3.42 d/10a的速率延长.从年代际变化来看,初霜日20世纪90年代以后开始明显推迟,终霜日90年代之后明显提早,无霜期是90年代开始明显延长.[结论]该研究为霜冻灾害的预测预防和农作物结构调整提供一定的参考. 相似文献
6.
[目的]研究火龙果的最佳冷却方法.[方法]首先进行不同终压(550,600及650Pa)的真空预冷、不同水温(0,1.5及3℃)的水冷及2m/s风速的强制通风(4℃)试验,然后,从每种试验中选择最优组进行比较,从中选择最适合火龙果的冷却方式.[结果]真空预冷最低只能将火龙果降到10℃左右;强制通风虽能把火龙果降到5℃以下,但时间过长,需要4-5h;冷水温度为0℃时,火龙果的温度降低最快,1h可降到5.5℃.[结论]火龙果的最佳冷却方式是0℃水冷. 相似文献
7.
[目的]研究桉蝙蛾幼虫的空间分布型.[方法]通过对广西北流市和陆川县等地的桉树人工林进行幼虫分布调查,共设10块标准地,采用6种不同的聚集度指标和回归模型分析法判断桉蝙蛾幼虫的空间分布格局.[结果]按蝙蛾幼虫主要分布在lm以下树干基部;按蝙蛾幼虫的空间分布型主体为聚集分布,是环境因素的作用结果.按蝙蛾幼虫在不同虫口密度下最适抽样数公式n=t2(1.1/m+0.674 4)/D2和序贯抽样决策限模式:T'0(n),T"0(n)=n±1.332√n(取m0=1).[结论]研究结果为桉蝙蛾的调查取样和预测预报工作提供了科学依据. 相似文献
8.
原生污泥经M1固化剂、木屑与煤粉按100:5:10:20(w/w)比例混合均匀,自然风干5d后制得改性污泥燃料。改性污泥燃烧结果表明:燃烧的经济风速为1~4m/s;燃烧时间随通风风速增大,颗粒粒径减小而减少.且颗粒粒径的影响较为显著;理想通风条件下,改性污泥燃烧烟气中SO2的浓度为44.6mg/m3,比原生污泥降低了52.4%,与煤粉SO2浓度相近;实际燃烧过程中,颗粒物浓度达到276mg/m3。 相似文献
9.
[目的]采用HPLC法测定棉团铁线莲(Clematis hexapetala)根及茎叶中齐墩果酸含量,为进一步开发棉团铁线莲药用资源提供理论依据.[方法]色谱柱为YW-C18柱(4.6 mm×150.0 mm,5 μm); 流动相为甲醇-水(V∶V=90∶10);检测波长为220 nm;进样量为10 μl;流速为1.0 ml/min;柱温为25 ℃.[结果]棉团铁线莲根中齐墩果酸的含量为0.175 2%,茎叶中齐墩果酸的含量为0.096 3%.[结论] 该方法简单、快速、准确,可用于棉团铁线莲中齐墩果酸的含量测定;同时该研究为评价棉团铁线莲茎叶的药用价值提供了参考,为进一步开发棉团铁线莲药用资源和质量控制提供了科学依据. 相似文献
10.
[目的]研究竹炭制备高比表面积活性炭及其电容性质.[方法]采用竹材加工剩余物制成的竹炭为原料,以氢氧化钾为活化剂制备了双电层电容器用活性炭,并通过正交试验研究了液固比、活化温度、活化时间及升温速率对产品吸附性能的影响.[结果]得到最优的活化工艺参数如下:碱炭比为4∶ 1,活化温度为770 ℃,活化时间为60 min,升温速率为10 ℃/min,比表面积高达2 379 m2/g,但其质量比电容不是最大.当比表面积为2 121 m2/g时,质量比电容最大(323 F/g),但其体积比电容偏小.[结论]为研制高比电容量且具有实际应用价值的电极材料提供了依据. 相似文献
11.
12.
Two studies investigated the role of expressive vocal behavior (specifically, speech rate and loudness) in fear and anxiety and in sadness and depression. In the 1st study, participants spoke about personally experienced fear and anxiety-arousing and neutral events using 3 different voice styles: fast and loud, normal, and slow and soft. In the 2nd study, participants spoke about personally experienced sad or depressing and neutral events using the same 3 voice styles. In both studies, the participants' highest levels of subjective affective and cardiovascular (CV) arousal occurred when they spoke about the emotional events in a mood-congruent voice style: fast and loud in the case of fear and anxiety, and slow and soft in the case of sadness or depression. Mood-incongruent voice styles canceled the heightened levels of CV arousal normally associated with these negative emotions. The voice-style manipulation had no significant effect on the participants' levels of CV arousal during the neutral discussions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
13.
Despite the use of multimodal therapy, higher-grade glioma is still uniformly fatal in the adult population. There is a considerable difference between the length of survival in each given patient, even within the same tumor type and malignancy grade group, suggesting that there are factors that might differentially influence outcome. To identify such factors, 107 patients with anaplastic or malignant glioma were retrospectively investigated. Clinical parameters and paraclinical data on the p53, mdm2, and EGFR genes at the DNA or protein level were evaluated by univariate analysis and Cox proportional hazards regression modeling. Kaplan-Meier survival estimation demonstrated that immunohistochemical positivity for mdm2 protein in patients with anaplastic astrocytoma or with glioblastoma multiforme was associated with a shorter survival time (p = 0.02). P53 gene mutations and immunopositivity for the epidermal growth factor receptor (EGFR) protein were not significantly related to poor prognosis. The Cox proportional hazards model revealed immunohistochemical positivity for p53, mdm2, or for both of them, the presence of postoperative irradiation, and the extent of surgical resection of tumor to be variables significantly associated with prolonged survival. EGFR overexpression, age over 60 years, and Karnofsky performance score below 40 points did not significantly shorten survival time. In conclusion, the present study identified immunohistochemically detected mdm2-protein overexpression as a statistically significant negative prognostic parameter in patients bearing anaplastic or malignant glioma. Association analysis of variables revealed a possible correlation between mdm2 and p53, which is also consistent with the biological interaction mode of both proteins in vivo. 相似文献
14.
BACKGROUND: As aging research increasingly reflects an effort to dissociate true time-driven changes from those that can be improved, sexuality in later life remains largely unexplored. Several problems are evident. There is a lack of normative data, a lack of a conceptual framework relating to the biology, psychology, and sociology of sex, and an attitudinal resistance that obscures the entire topic. METHODS: We conducted a three-part instructional series on major topics involved with sexuality and aging. We surveyed our group of attendees (n 158, average age 68 for males, 65 for females) before and after the series. RESULTS: A remarkably robust sex life was evidenced by both the men and the women, even until advanced old age. Yet, a substantially decreased involvement was reported from 10 years earlier. Despite current activities, people of both sexes wished they were participating even more than they currently were. Impotency was identified as the major negative feature for the men; relationship problems were for the women. A questionnaire 6 months after the series reported improved sexual attitudes, but no change in sexual activities from the earlier survey. CONCLUSION: Sexuality is a major quality-of-life issue which persists into old age. Our study showed that the usual sexual practices reported by our group were not considered by them to be ideal. The intervention of this instructional series provided improved sexual attitudes but not performance. Additional studies are encouraged. 相似文献
15.
M Engelhardt I Reuter J Freiwald T B?hme A Halbsguth 《Canadian Metallurgical Quarterly》1997,26(9):755-759
Spondylolysis and spondylolisthesis occur predominantly in the lower lumbar spine. Besides congenital defects such as predisposition of spondylolysis the correlation between competitive sports activities and an increased incidence of spondylolysis is proved. In early stages, complete healing can be achieved by conservative treatment (abstinence from sports activities for 3 months, orthesis). Persistence of pain, neurologic symptoms and progression of vertebral slipping are indications for operative treatment (reconstruction of the isthmus, dorso-ventral spondylodesis). The exercise tolerance depends on the extent of instability, progression of vertebral slipping and clinical symptoms. The limits of exercise tolerance vary among the individual athletes and require the decision of the physician. Backstroke swimming, abdominal and back muscle strengthening exercises, and types of sport involving smooth movements are advisable. Sports education in school is possible without restriction in patients with stable spondylolysis and in those with spondylolisthesis without unfavourable concomitant factors. 相似文献
16.
OBJECTIVE: To test the validity of Benjamin Franklin's maxim "early to bed and early to rise makes a man healthy, wealthy, and wise." DESIGN: Cross sectional analysis of sleeping patterns in a nationally representative group of elderly people, and longitudinal investigation of mortality. SETTING: Eight areas in Britain (five in England, two in Scotland, and one in Wales). SUBJECTS: 1229 men and women aged 65 and over who in 1973-4 had taken part in a survey funded by the Department of Health and Social Security and for whom data on sleeping patterns, health, socioeconomic circumstances, and cognitive function had been recorded. MAIN OUTCOME MEASURES: Self reported income, access to a car, standard of accommodation, performance on a test of cognitive function, state of health and mortality during 23 years of follow up. RESULTS: 356 people (29%) were defined as larks (to bed before 11 pm and up before 8 am) and 318 (26%) were defined as owls (to bed at or after 11 pm and up at or after 8 am). There was no indication that larks were richer than those with other sleeping patterns. On the contrary, owls had the largest mean income and were more likely to have access to a car. There was also no evidence that larks were superior to those with other sleeping patterns with regard to their cognitive performance or their state of health. Both larks and owls had a slightly reduced risk of death compared with the rest of the study sample, but this was accounted for by the fact that they spent less time in bed at night. In the study sample as a whole, longer periods of time in bed were associated with increased mortality. After adjustment for age, sex, the presence of illness, and other risk factors, people who spent 12 or more hours in bed had a relative risk of death of 1.7 (1.2 to 2.5) compared with those who were in bed for 9 hours. The lowest risk occurred in people who spent 8 hours in bed (adjusted relative risk 0.8; 0.7 to 1.0). CONCLUSION: These findings do not support Franklin's claim. A "late to bed and late to rise" lifestyle does not seem to lead to socioeconomic, cognitive, or health disadvantage, but a longer time spent in bed may be associated with increased mortality. 相似文献
17.
Mechanical allodynia (MA) following hand injury is a well-documented clinical problem. The purpose of this pilot study was to examine the relationship between hand MA and the upper limb tension test (ULTT). The ULTT mechanically stresses the neural structures from the C5/6/7 neural foramina to the median nerve distally. This study examined 29 subjects with unilateral hand MA before and after a 2-week neural self-mobilization programme. There was a significant difference between the subjects' affected and unaffected sides when tested using the ULTT, both in reproduction of symptoms and in reduced range of motion of the ULTT. Following the self-mobilization program, there was an improvement in the range of the ULTT, and subjects reported a reduction in their symptoms. Complete recovery was not obtained in all cases. The results of this study suggest that the ULTT is a useful tool both in assessment and treatment of subjects with hand MA. 相似文献
18.
刘印华 《有色冶金设计与研究》2006,27(2):47-50
根据深云立交桥梁的检测结果,对该桥目前的整体状况、工作状态,及其使用情况做出综合评价,对桥的病害原因进行了分析,并提出合理的加固方案。 相似文献
19.
20.
贺冬梅 《湖南冶金职业技术学院学报》2009,9(4):46-48
劳伦斯小说《儿子与情人》一个鲜明的语言特色就是标准英语和当地方言频繁的语码转换。莫瑞尔用方言来对抗妻子,而妻子坚持用标准英语,偶尔也用方言来讽刺、挖苦丈夫。语码转换反映了劳伦斯男女二元对立的哲学思想。 相似文献