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1.
针对钢管与砼膨胀系数的差异(分别为1.2×10-5/℃和0.7×10-5/℃),阐述低负温(-5℃至-17℃)下钢管砼柱砼顶升法施工原理、热工计算、外加剂选择以及开孔排气、压力灌浆等关键工艺方法步骤.最后,作出砼强度数理统计分析和技术经济效果评述.可供同类结构施工参考.  相似文献   

2.
报道了Tb3+ - TR络合物探针用于研究脱氢酶,并建立了3种典型脱氢酶的定量测定方法,测定乙醇脱氢酶(ADH)、苹果酸脱氢酶(MDH)和葡糖- 6 -磷酸脱氢酶(G 6 PDH)的线性范围分别为: 2. 14×10-6 ~5. 50×10-5 g/mL、4. 17×10-6 ~1. 03×10-4 g/mL和5. 02×10-6 ~3. 51×10-5 g/mL;检测限分别为: 1. 02×10-7 g/mL、5. 32×10-7 g/mL和1. 25×10-6 g/mL.研究结果表明,Tb3+ TR络合物除可以作为脱氢酶定量测定的灵敏探针外,还可以用作指示乙醇脱氢酶(ADH)热变性过程的灵敏探针,探测结果显示ADH的热变性过程在50~60℃有一突变,从另一角度阐明了ADH的热变性过程不是长期以来一直认为的“全或无”的过程,而是一个构象渐变的过程.由于ADH分子是由酶蛋白和NAD+组成的全酶,其变性失活过程,除了与酶蛋白有关以外,还与NAD+有关.利用Tb3+ - TR络合物荧光探针可以较灵敏地监测到这一点.  相似文献   

3.
离子对反相高效液相色谱法测定VB2,VB6,VB12,VC和叶酸   总被引:1,自引:0,他引:1  
建立了用离子对反相高效液相色谱法同时测定VB2,VB6,VB12,VC和叶酸含量的方法.用HypersilC18色谱柱(ODS2,5 μm,4.6 mm×150 mm,),V(甲醇)V(0.5%醋酸溶液)=3070,其中每升流动相加入2.5 mmol的戊烷磺酸钠作为流动相.柱温30℃时于254 nm波长处以外标法测定.结果表明VB2,VB6,VB12,VC和叶酸的浓度与峰高成良好的线性关系.VB2的线性范围为2.0×10-7~8.0×10-6g/mL(r=0.999 8),VB6的线性范围为2.0×10-6~5.0×10-4g/mL(r=0.999 0),VB1 2的线性范围为2.0×10-7~8.0×10-4g/mL(r=0.999 9),叶酸的线性范围为2.0×10~5.0×10-5g/mL(r=0.998 7),VC的线性范围为5.0×10-7~8.0×10-5g/mL(r=0.999 1).VB2,VB6,VB12,VC和叶酸的检测限分别为6×10-9g/mL,6×10-8g/mL,7×10-9g/mL,1×10-9g/mL和6×10-8g/mL实验表明该法准确,快捷,操作简便,应用于蜂蜜和复合维生素片中维生素的测定,取得了很好的结果.  相似文献   

4.
敌百虫对九孔鲍稚鲍和真猛水蚤的毒性作用   总被引:3,自引:0,他引:3  
不同温度下 ,敌百虫对稚鲍的毒性作用不同 ,在水温 2 1~ 2 2℃下 ,2 4h、 4 8h、72h、96h的半致死浓度分别为 182mg/L、 4 6mg/L、10 6mg/L ,6 6mg/L ,安全浓度为 4 6mg/L ;水温 2 6~ 2 7℃ ,在相同时间内的半致死浓度分别降至 12 9mg/L、 11 1mg/L、 8 2 5mg/L和5 1mg/L ,安全浓度为 1 11mg/L ;敌百虫对真猛水蚤的毒性也是随着水温升高而增强 ,水温2 1~ 2 2℃ ,2 4h、 4 8h、 72h的半致死浓度分别为 2 7× 10 - 1mg/L、 3 5× 10 - 2 mg/L、 2 0×10 - 2 mg/L ,安全浓度为 3 5× 10 - 2 mg/L ;当水温升至 2 6~ 2 7℃时 ,半致死浓度分别为 8 3× 10 - 2mg/L、8 3× 10 - 3mg/L、3 6× 10 - 3mg/L ,安全浓度为 8 3× 10 - 4mg/L 敌百虫对稚鲍的亚急性作用结果是 :在 0 4~ 2 0mg/L下生活 2 0d ,稚鲍的壳长、体重、摄食及存活率随其浓度的增大而降低 本文对九孔鲍工厂化育苗中如何正确使用敌百虫防治底栖桡足类提供了科学依据  相似文献   

5.
粉虱座壳孢对烟粉虱的致病力测定及其时间-浓度效应   总被引:4,自引:0,他引:4  
本研究用粉虱座壳孢 Aschersonia aleyrodis Webber孢子悬浮液 1× 10 5、5× 10 5、1× 10 6、5× 10 6和 1×10 7孢子 /ml,对烟粉虱 Bemisia tabaci(Gennadius) 2龄若虫进行致病力测定 ,并应用时间 -剂量 -死亡率模型研究了粉虱座壳孢对烟粉虱致死的时间和浓度效应 ,拟合良好。结果表明 ,粉虱座壳孢对烟粉虱的致病力较强 ,接种后第 9d,5× 10 6和 1× 10 7孢子 /ml两个浓度处理累计死亡率达 90 %以上 ;第 10 d的 LC50 和 LC90 分别为 2 .5 8× 10 5和 4 .6 7× 10 6孢子 /ml;在 5× 10 5- 1× 10 7孢子 /ml的浓度范围内 ,L T50 为 2 .6 1- 4.82 d  相似文献   

6.
本文探讨了蒿甲醚在0.25mol/L磷酸-50%甲醇体系中直流极谱的一些特性,确定了它在该体系中有一很好的受扩散控制为主的极谱波,其半波电位为-0.28V(对汞层阳极),温度系数为+1.9%/℃,电子得失数为2;在25.0℃时的扩散系数为:D=3.30×10~(-6)cm~2/s;在4.0×10~(-5)-8.0×10~(-4)mol/L浓度范围内有较好的线性关系.  相似文献   

7.
对端异氰酸酯基聚氨酯予聚体(PEU)分别与1,3—二(3—羟丙基)四甲基二硅氧烷(Ⅰ)和α,ω—二羟基聚二甲基硅氧烷齐聚物(Ⅱ)在THF/DOX中的反应动力学进行了研究。结果表明,反应程度直至6O%,这两种反应均为二级反应。PEU与Ⅰ对应于65、56和47℃三个温度的反应速度常数分别为6.3×10~(-2)、3.8×10~(-2)和1.68×10~(-2)1/mol·min, PEU与Ⅰ的反应活化能及频率因子分别为66,14kJ/mol和1.l×10~9;PEU与Ⅱ对应于65、56和47℃三个温度的反应速度常数分别为9.9×10~(-3)、2.4×10~(-3)和1.76×10~(-3)1/mol·min,PEU与Ⅱ的反应活化能及频率因子分别为85.81kJ/mol和1.43×10~(11)。  相似文献   

8.
低酸度介质中铀酰和dl-酒石酸的络合行为   总被引:1,自引:1,他引:0  
本文用阳离子交换法研究了低酸度介质中不同温度下 UO_2~(++)-dl-酒石酸的络合形成,证明在溶液中存在有 UO_2 HL~-,较高温度时还发现存在有 UO_2HL(H_2L)~(3-),在25、35、45和55℃时,β_1为1.5×10~(-6)、1.1×10~(-6)、6.6×10~(-7)、3.8×10~(-7);在45°C、55℃时,β_2为2.0×10~(-3)、4.2×10~(-3),求得△H(β_1)是—4.8千卡/克分子.  相似文献   

9.
烧成曲线对合成堇青石热膨胀系数的影响   总被引:3,自引:0,他引:3  
研究了不同烧成曲线对合成堇青石材料热膨胀系数的影响,提出了一种降低堇青石材料热膨胀系数的新途径。结果表明,采用成核-生长曲线法烧成时,试样的热膨胀系数为1.6-1.8×10-6/℃左右,比采用直接升温法时的热膨胀系数(2.0-2.4×10-6/℃)的值降低0.3-0.5×10-6/℃左右。  相似文献   

10.
1-(2-吡啶偶氮)-2-萘酚(PAN)对鲁米诺-亚铁氰化钾化学发光反应有良好的催化性能,实验结果表明:在1.0×10-5-1.0×10-7mol/L范围内,发光强度与PAN的浓度之间有良好的线性关系,检测极限为5.6×10-8mol/L。同时发现一些金属对此化学发光反应有强的抑制作用,为此建立了用此反应测定这此金属离子的新方法,测定Ni2+,Cr3+,Zn2+,Co2+和Cu2+的检测极限分别为1.0×10-9mol/L、1.0×10-8mol/L、1.0×10-8mol/L、5.0×10-9mol/L和6.0×10-9mol/L,相对标准偏差在1.28-3.10%(n=11)范围内。  相似文献   

11.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to  相似文献   

15.
Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications (up to 574.8 km/ h test speeds or 380 km/h commercial speeds) in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.  相似文献   

16.
17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.  相似文献   

19.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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