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1.
有机高分子絮凝剂AUF的研制及其除油效果测定   总被引:3,自引:0,他引:3  
以尿素、甲醛为原料合成脲醛树脂,加入环氧氯丙烷对树脂进行改性,再加入三乙铵进行季胺化,得到改性脲醛树脂季铵盐絮凝剂AUF。在WEMCO浮选机上考察AUF的除油性能及最佳合成条件。结果表明:AUF投药量为10mg/L时,出水中油浓度达到国家排放标准;当甲醛、尿素、环氧氯丙烷三者的摩尔比为2:1:0.5,季铵化温度为80~110C,反应时间为4~5h时,得到的絮凝剂AUF除油效果最好。  相似文献   

2.
本文根据中国光温生态试验资料及四川水稻品比试验与气象观测的历史资料,讨论了早、中稻感温性和对温度的适应性,分析了播期、纬度、海拔等因素与稻种需求积温量的关系,以水稻品种类型对热量的适应性指标为依据,考虑四川水稻气候生态的差异性,划分出水稻综合气候生态类型区。  相似文献   

3.
东南亚珠芽魔芋多苗接力生长特性及应用前景   总被引:4,自引:2,他引:2  
以珠芽魔芋人工诱导开花进行规模化无性育种,可将魔芋繁殖系数从1位数提高约330倍;采用催苗技术让种子及叶面球茎提早出苗,可显著延长魔芋生长周期,使魔芋种植周期由3年缩短为1年;魔芋种子1年生长最高膨大率超过5000倍,当年即形成1180g球茎;魔芋叶面球茎最大膨大率超过100倍,两者种植一季魔芋即可用于加工.突破了魔芋繁殖系数低、膨大率低导致种植周期长的双重困局,显著降低了病害风险,大幅度缩短了魔芋种植周期,从而突破魔芋传统种植区域的地理限制,使魔芋总产量超常规增长.  相似文献   

4.
四川省中稻→冬水田近2000万亩,集中分布于盆地丘陵区,资源丰富。为发挥它的增产潜力,将中稻改为“双杂”间作稻,增产极显著。其中威优49间汕优63,双行间作,早稻科距8cm、窄行15cm、宽行49cm 中嵌插2行晚稻的小区,亩产728.0~776.9kg,比同田毗邻的汕优63中稻增产31.4%~45.0%,增加纯收入56.46元,为丘陵区中稻→冬水田的合理利用开辟了一条很好的途径。  相似文献   

5.
香格里拉是我国西部旅游的一支“生力军”,其发展是基于高品位的旅游资源和优越的政策环境,并顺应了市场需求。香格里拉旅游地的生成经历了较长的探索期,并没有明显的参与期,几乎直接进入了发展期。市场需求导向是香格里拉旅游地生成机制的内在逻辑,环境因素是背景,政策因素则起到了直接推动作用。香格里拉的旅游发展形成了以生态旅游为主导、以民族生态旅游接待村为发展载体、以开展藏民家访为具体形式的模式。分析认为,生态与旅游的和谐、基础设施建设、规范化管理、提高居民的参与能力是优化这种模式的路径选择。  相似文献   

6.
为研究西安环境空气中二噁英类物质的浓度变化特征,选择西安市采暖季和非采暖季开展持续22周监测工作,并使用高分辨气相色谱高分辨质谱法对样品进行分析研究。结果显示:该市采暖季和非采暖季二噁英浓度均低于国内其他城市;采暖季期间化石能源燃烧是二噁英毒性当量质量浓度升高的主要原因;17种二噁英同类物浓度在时间与空间上分布特征基本相同。在采暖季期间,二噁英主要存在于细颗粒物中;在非采暖季,低氯代二噁英及呋喃主要存在于气相中,高氯代二噁英及呋喃主要存在于颗粒物中。采暖季期间,可通过采用非化石能源燃烧和佩戴PM2.5口罩减少二噁英对人体的危害。  相似文献   

7.
张波  鲁振宇  张葵  颜萍 《资源开发与市场》2009,25(12):1150-1152
对龙门山成都段平原和中低山区旅游舒适气候进行了分析和评价,旨在为合理开发利用龙门山旅游气候资源,为旅游者选择最佳旅游季节提供依据。结果表明,该区为一类生态旅游圈,平原及低山区平均每年舒适天数在180d以上;平原和中山区旅游舒适气候有显著差异,适宜旅游期平原比中山区长2—3个月;最佳旅游期中山区比平原长1个月左右,最佳旅游期平原出现在春秋季,而中山区集中在5—10月。  相似文献   

8.
利用2013~2015年廊坊市气象站霾、气温、相对湿度、气压、风速、降水、日照等地面观测资料以及环保局PM2. 5资料,对各级霾的季、日气象要素特征进行了深入研究,结果表明:(1)廊坊市各级霾均有明显的季节性分布特征,轻微霾以夏季为最多,轻度、中度霾以秋季为最多,重度霾以冬季为最多;(2)重度霾的日平均气温接近相应季节的季平均值,轻微及中度霾则与季平均气温相差较大,轻度霾与季平均气温相差最大;(3)各级别霾的平均相对湿度值均高于相应季平均值,且以重度霾高出平均值为最多;(4)较低的气压利于重度霾的形成;(5)各级别霾日平均风速均小于同季平均风速,以重度霾偏小最多;(6)随着霾级别加重,日照时数明显减少;(7)各级别霾日中无降水日占比最多,表明降水可以抑制霾的形成。  相似文献   

9.
以芦苇秸秆为原材料,通过铁负载及季胺化改性的方式制备了新型复合吸附除磷材料.利用扫描电镜分析(XRD)、红外吸收光谱(IR)对样品进行了表征,选择磷酸盐作为吸附质考察其吸附性能,并通过单因素和响应面法优化了材料制备的工艺.实验结果表明,复合材料制备最优工艺条件为:氢氧化钠浓度7.7%、交联温度81℃、铵化温度80℃、铁...  相似文献   

10.
以二乙胺盐酸盐、环氧氯丙烷和十八烷基二甲基叔胺为原料,合成十八烷基多头基季铵盐表面活性剂。采用电导率的方法,测定了合成产物的临界胶束浓度;并采用分光光度法,研究了多头基季铵盐在土壤表面的静态吸附行为,探讨了吸附时间、液固比、多头基季铵盐浓度对吸附行为的影响。结果表明,合成产物为目标产物,合成产物的临界胶束浓度(cmc)为1.2×10~(-4)mol/L,多头基季铵盐在土壤表面达到吸附平衡的时间为6 h,最佳液固比为400:1,吸附等温线符合Langmuir单分子层吸附,饱和吸附量为4.17×10~(-4)mol/g。  相似文献   

11.
本文论证了湖北稻区冬半年的农业资源及其特点,讨论了开发本区冬季农业的意义、发展方向及其关键措施。  相似文献   

12.
试验研究表明,当早稻收获时间作晚稻才开始幼穗分化,即适宜早、晚稻出穗开花之间有60多天的时间,种植双杂间作稻就可获得好的收成,效果、效益都很显著。1992年用D 优287间汕优63,在达县永进乡的示范田中个别田块产量已达15t/ha,而盆地丘陵区适宜早、晚稻出穗开花之间的时间多数地区不到70天,种植双杂连作稻有困难。且双杂间作稻在抗灾增产,合理利用农村劳动力,提高稻田复种等方面优于双杂连作稻。因此,四川盆地丘陵区的中稻→冬水田在耕作改制中发展部分双杂间作稻是恰当的,其范围在巴中、盐亭、简阳一线以南海拔400m 以下的广大丘陵区。  相似文献   

13.
Disproportionately little attention has been paid to the dry season trade‐off between rice and (inland capture) fish production on the floodplains of Bangladesh, compared to the same trade‐off during the flood season. As the rural economy grows increasingly dominated by dry‐season irrigated rice production, and floodplain land and water come under ever‐increasing pressure during the dry winter months, there is an urgent need to focus attention on these dry months that are so critical to the survival and propagation of the floodplain resident fish, and to the poor people that depend on these fish for their livelihood. This article examines three important dry‐season natural resource constraints to floodplain livelihoods in Bangladesh, and finds a common factor at the heart of all three: rice cultivation on lands at low and very low elevations. The article articulates the system interlinkages that bind these constraints and the long‐run trend towards irrigated rice cropping on lower‐lying lands, and suggests a management approach based on locally tailored strategies to arrest this trend. Apart from its direct relevance to the floodplains of Bangladesh, which support more than 100 million people, these lessons have relevance for river floodplain systems elsewhere in the developing world, notably the Mekong Delta.  相似文献   

14.
通过2年的定点调查,研究了湘中某工业区附近农田土壤、糙米中重金属含量状况;并对重金属在水稻植株中的含量分布,以及影响糙米中重金属含量的土壤因素进行了探讨。  相似文献   

15.
稻壳纳米SiO2研究及开发利用   总被引:3,自引:0,他引:3  
采用强酸消煮方法从水稻稻壳中提取二氧化硅.EDX能谱分析表明,提取物中不含其它杂质,在透射电子显微镜下观察到稻壳二氧化硅是由直径为50nm的凝胶颗粒组成.讨论了纳米二氧化硅的开发前景和利用途径.  相似文献   

16.
通过多年的试验、示范证明,杂交稻具有旱能保产、湿能增产的特点,特别是在通气式大田水层栽插、湿润管理的条件下,具有节水、增产、改良土壤的作用。对在灌溉条件较差的丘陵山区和圩区发展水稻生产有积极的作用。  相似文献   

17.
In vitro methane emissions from different rice paddy soils and algal mats were studied under anoxic and atmospheric conditions. Methane production from rice paddy soils cultivating different strains of rice was found to be appreciable under anoxic conditions, but considerably reduced under atmospheric conditions, and dependent on rice cultivars (strains). A contradictory result was obtained with a Gobindabhog cultivated rice field (a strain of rice with aroma), where methane yield under anoxic was greater than that under atmospheric conditions. The results indicated aerotolerance of methanogens or the possible existence of microaerophilic methanogens. The results from algal mats corroborated these findings.Methane has been considered to be an important greenhouse gas contributing significantly to global thermal warming (GTW). Flooded rice paddy fields have been considered to be a most prominent source of abiogenic methane emission, though considerable uncertainty exists regarding the true estimates of methane emission. Factors affecting methane emission and its abatement have been examined. In spite of increasing methane emission, rice cultivation leads to enormous utilization of the green house gas carbon dioxide and release of oxygen to the atmosphere. Thus, the contribution of methane to GTW (from rice paddy cultivation) is more than compensated by carbon dioxide absorption.Appropriate steps have been suggested for the reduction of methane emissions, the most important of which is the restoration of methane sinks.  相似文献   

18.
本文论证了湖北稻区的资源具有三大特点。因此,认定该区应细分为:东南部早三熟双季稻区,中部单、双季稻两热三熟并存区,西北部单季稻两熟区。笔者认为,本区近10年发展麦稻、油稻稻、油稻减少肥稻稻、肥稻其主流是好的;讨论了紫云英大量减步后如何解决有机肥源匮乏的问题。主张今后应积极开发冬种,积极提倡冬作起厢分带间套,既稳定大宗作物的发展,又增产经作、饲料、蔬菜、绿肥,以提高稻田的经济效益。  相似文献   

19.
This study investigated seasonal and geographical variation in the fluorescence properties of dissolved organic matter (DOM) in a river system that includes rice paddy fields in its watershed. The river system covers a northern area of the main island of Japan, and between 6 and 45% the watershed area of the tributaries is paddy fields. Water samples were collected monthly from eight tributaries for 1 yr, and the fluorescence properties of DOM were monitored by combined excitation-emission matrix (EEM) and parallel factor analysis. The EEM was statistically decomposed into six fluorescence components with different environmental dynamics. The relative proportion of these components varied with season and geographic location, the former having a greater effect than the latter. Seasonal variation is largely attributed to changes in the source of DOM associated with irrigated rice cultivation practice. The fluorescence component composition showed a stronger autochthonous signature, which varied over a wider range during off-cropping period (October-April) than cropping period (May-September). During the cropping period, a large amount of allochthonous DOM with relatively similar quality was transported into river water from flooded paddy fields and masked the variability in the quality of DOM among tributaries. Therefore, irrigated rice cropping practices are considered to be one of major factors that influence seasonal and geographical variation of fluvial DOM composition.  相似文献   

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