珠江流域1960―2012年降雨侵蚀力时空变化特征     

赖成光  陈晓宏  王兆礼  赵仕威  吴旭树  于海霞 《农业工程学报》2015,31(8):159-167

降雨侵蚀力反映了降雨对土壤侵蚀的潜在能力,研究其时空变化特征对流域土壤侵蚀监测、评估、预报和治理等工作具有重要意义。根据珠江流域43个气象站1960-2012年逐日降雨资料计算各站点降雨侵蚀力,采用线性回归,Mann-Kendall方法,小波分析和Kriging插值等方法对流域降雨侵蚀力进行了时空变化分析。结果表明:珠江流域多年平均降雨侵蚀力值的分布范围为1 858.0~14 656.6 MJ·mm/(hm2·h),平均值为7 177.1 MJ·mm/(hm2·h),与多年平均降雨量极显著相关(相关系数0.952,P0.01),空间分布规律与多年平均降雨基本一致,即总体上均呈从东到西逐渐递减的规律,被统计站点的降雨侵蚀力随着经度增加而增加,但随纬度增加而减少;流域年、季节、汛期和非汛期降雨侵蚀力变化趋势均不显著,均没有发生显著的突变,其中春、秋两季降雨侵蚀力呈下降趋势,其余时间段呈上升趋势;珠江流域大部分地区年降雨侵蚀力呈上升的趋势,其中韶关站点上升显著,沾益站、风山站、河池站、百色站、柳州站、融安站和桂林站的冬季降雨侵蚀力同样上升显著,这些地区面临的水土保持压力较大;流域年均降雨侵蚀力变化主周期为3.8 a,且存在2.0~7.0 a的振荡周期。研究结果可为珠江流域的水土保持、农业和生态保护,灾害控制等工作提供科学决策依据。  相似文献   

Stages in the History of China's Acid Rain Control Strategy in the Light of China-Japan Relations     

Haiping Lai  Hiroyuki Kawashima  Junko Shindo  Keiji Ohga 《Water, air, and soil pollution》2001,130(1-4):1843-1848

We analyze the history of acid rain in China over the last three decades in the light of the relationship between China and Japan. China has been aware of the problem of acid rain and has been conducting scientific research since the late 1970s. However, little effort has been put into practical countermeasures. In the early 1990s, acid rain was re-evaluated as an international environmental problem. Meanwhile, Japan became concerned about trans-boundary air pollution from China. What is important is that Japan's concern strongly influences China's acid rain policy. In the context of growing international concern for environmental problems, China has taken remarkable steps to control acid rain. In this respect, dealing with acid rain is an issue of national pride for China.  相似文献   

Monitoring lipase-catalyzed interesterification for bulky fat modification with FT-IR/NIR spectroscopy     

Chang T  Lai X  Zhang H  Søndergaard I  Xu X 《Journal of agricultural and food chemistry》2005,53(26):9841-9847

This work demonstrates the application of FT-IR and FT-NIR spectroscopy to monitor the enzymatic interesterification process for bulky fat modification. The reaction was conducted between palm stearin and coconut oil (70:30, w/w) with the catalysis of Lipozyme TL IM at 70 degrees C in a batch reactor. The blends and interesterified fat samples in liquid form were measured by attenuated total reflectance based FT-IR (spectra region, 1516-781 cm(-1)) and transmission mode based FT-NIR (spectra region, 5369-4752 cm(-1)) with the temperature of both controlled at 70 degrees C. The samples in solid form were also measured by reflectance-based FT-NIR (spectra regions, 7037-6039 and 5995-5612 cm(-1)) at room temperature. Calibrations of FT-IR and FT-NIR for conversion degrees (evaluated by triglyceride profile), solid fat contents (SFC), and dropping points of interesterified products were carried out by using partial least-squares regression. High correlations (r > 0.96) were obtained from cross validations of the data estimated by FT-IR, FT-NIR, and the above-mentioned conventional analytical methods, except for correlations (r = 0.90-0.95) between FT-IR and SFC profiles. Overall, FT-NIR spectroscopy coupled with transmission mode measured at 70 degrees C had the highest correlations, which also had the closest conditions to the sampled products in the process, indicating a great potential for implementation as an on-line control for monitoring the enzymatic interesterification process.  相似文献   

玉米根茬根土分离方式的试验研究     

武涛  马旭  陈学深  陈耿文  赖远宏 《湖南农业大学学报(自然科学版)》2015,41(3)

为确定较优的玉米根茬根土分离作业方式与作业参数,在根茎类作物根土分离试验台上进行了碾压、击打和抖动的单独及组合作业方式的根土分离效果对比试验。结果表明,采用碾压+击打组合方式对低含水率(10%~15%)的玉米根茬样品进行根土分离优于其他作业方式。为优化碾压+击打组合作业方式的作业参数,根据Box–Behnken试验设计原理,以根土分离率和作业功耗为性能指标,以轧距、飞锤转速和飞锤质量为试验因素进行试验,建立了根土分离率以及作业功耗的回归模型,通过响应曲面法分析指标与因素间的相互作用,并对回归模型进行多目标优化。优化获得的最佳作业参数为:轧距22 mm,飞锤转速200 r/min,飞锤质量0.3 kg,试验验证根土分离率为95.44%,作业功耗为0.72 k W,试验值与理论预测值基本一致,表明采用碾压+击打组合方式具有良好的根土分离效果。  相似文献   

滨湖水牛血液蛋白多态性与数量遗传特性研究     

赖松家  余超群 《四川农业大学学报》1997,15(2):246-249,179

采用电泳法对滨湖水牛血红蛋白、血清运铁蛋白、淀粉酶、白蛋白的多态性进行了检测。结果表明，血红蛋白多态型表现为ＡＡ、ＡＢ、ＢＢ三种类型，其频率分别为０．０１２、０．０５８、０．９３０，并且发现一头三条泳带的稀有变异体，基因ＨｂＡ、ＨｂＢ频率分别为０．０４１、０．９５９。运铁蛋白多态型表现为ＡＡ、ＡＤ、ＤＤ、ＡＥ、ＤＥ五种类型，频率为０．０５８、０．３５６、０．５１７、０．０１２、０．０５８，基因ＴｆＡ、ＴｆＤ、ＴｆＥ的频率为０．２４１４、０．７２４１、０．０３４５。淀粉酶多态型表现为ＡＡ、ＡＢ、ＡＣ、ＢＣ四种类型，频率为０．１２８２、０．１０２６、０．７１７９、０．０５１３，基因ＡｍｙＩＡ、ＡｍｙＩＢ、ＡｍｙＩＣ频率为０．５３８５、０．０７８９、０．３８４６。白蛋白多态型表现为ＡＡ、Ａｘ、Ｂｘ、ｘｘ四种类型，频率为０．０８０４、０．２９８８、０．０２３０、０．５９７７，基因ＡｌｂＡ、Ａｌｂｘ、ＡｌｂＢ频率０．２３００、０．７５８６、０．０１１５。对滨湖水牛遗传变异性研究表明其杂合度较低为０．２５７８。  相似文献   

荆州古城旅游特色创新浅析     

周来 《湖北农学院学报》2003,23(3):186-188,195

从荆州城的现状出发，针对历史文化名城的特点，对其旅游特色创新问题进行了分析，并对城区具体景点的建设以及城市色彩等问题提出了一些建议。  相似文献   

原油等熵压缩温升测定及研究     

许振民  辛玉兰 《油气储运》1995,14(2):14-17

采用反平衡法测试泵的效率，具有测试参数少（不需要测定泵流量），易于实现等优点，但是原油等熵压缩温升参数及其测试方法需要深入研究。实测液体等熵压缩温升要在绝热，压力稳定的条件下进行，并取升压测得的温升△ｔｐ和降压测得的温降△ｔｐ的算术平均值，作为等熵温升。从对原油实测的等熵压缩温升结果来看，原油的等熵压缩温升与原油性质，被压缩原油的温度，压力，密度有关，其中与原油密度的关系较为明显。介绍了测试这一参  相似文献   

鸡大肠杆菌病研究Ⅰ．鸡E．Coli人工感染模型的建立及致病力评价   总被引：3，自引：0，他引：3  

赖平安  崔德凤  高立武 《畜牧兽医学报》1996,(3)

本文对分离自典型大肠杆菌病变和粪便的４５株Ｅ．Ｃｏｌｉ通过４日龄雏鸡人工感染试验建立了大肠杆菌病的人工感染模型，并对菌株的致病性进行评价。结果表明：４日龄雏鸡颈部皮下接种０．２ｍｌ菌液，接种后，前６５ｈ内雏鸡死亡率≥６０％的菌株为强致病力菌株；死亡率＜６０％，或出现典型大肠杆菌病变为中等致病力菌株；试验期不引起雏鸡死亡也无病变者为无致病力大肠杆菌。试验的１３株分离自粪便的苗株，２株为中等致病力，１１株为无致病力；３２株分离自典型病变的菌，９株为强致病力菌，１５株为中等致病力，８株为无致病力。  相似文献   

喷灌设施的小气候效应在苗木培育中的影响     

来志法  谢国军  邱春英 《中国林副特产》2008,(6):33-34

喷灌设施对苗圃小气候影响的试验表明：在夏季高温季节，可为苗木生长提供温凉湿润的气候条件，与常规相比，白天平均温度降低3．1℃，最高气温降低3．4℃，可有效减轻苗木受高温干旱的影响。喷灌设施应用可使苗木成活率提高23．1％，促进成形苗出圃速度；1hm^2年增加产值近8万元，经济效益明显。  相似文献   

右心室心肌梗塞心电图的观察（附22例分析）     

赖兆新 《湛江医学院学报》1996,(2)

对２２例右心室心肌梗塞（ＲＭＩ）患者住院期的心电图作连续观察，发现多数仅累及Ｖ３Ｒ、Ｖ４Ｒ两个导联；相应导联病理性Ｑ波出现率占６８；２％，多数表现为ＱＳ、Ｑｒ、ＱＲ，其次为ｑＲ、ｑｒ；ＳＴ段抬高１～２ｍｍ占８１．１％，起病４８、７２小时内分别有７７．３％和９０．９％的病例ＳＴ段回到等电位线；Ｔ波多在４８小时内变为倒置，极少形成冠状Ｔ波。结果表明ＲＭＩ的心电图没有单纯性左室梗塞（ＳＬＭＩ）典型，演变快，提示梗塞范围小且程度较轻。  相似文献