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1.
2.
Models for weather and climate prediction are complex, and each
model typi-cally has at least a small number of phenomena that are
poorly represented, such as perhaps the Madden-Julian Oscillation
(MJO for short) or El Ni\~{n}o-Southern Oscillation (ENSO for short)
or sea ice. Furthermore, it is often a very challenging task to
modify and improve a complex model without creating new
deficiencies. On the other hand, it is sometimes possible to design
a low-dimensional model for a particular phenomenon, such as the MJO
or ENSO, with significant skill, although the model may not
represent the dynamics of the full weather-climate system. Here a
strategy is proposed to mitigate these model errors by taking
advantage of each model''s strengths. The strategy involves
inter-model data assimilation, during a forecast simulation, whereby
models can exchange information in order to obtain more faithful
representations of the full weather-climate system. As an initial
investigation, the method is examined here using a simplified
scenario of linear models, involving a system of stochastic partial
differential equations (SPDEs for short) as an imperfect tropical
climate model and stochastic differential equations (SDEs for short)
as a low-dimensional model for the MJO. It is shown that the MJO
prediction skill of the imperfect climate model can be enhanced to
equal the predictive skill of the low-dimensional model. Such an
approach could provide a route to improving global model forecasts
in a minimally invasive way, with modifications to the prediction
system but without modifying the complex global physical model
itself. 相似文献
3.
手性奎宁-卟啉锰催化剂的合成及其催化性能 总被引:1,自引:0,他引:1
为了寻找催化活性、相转移活性和手性诱导为一体的卟啉配体[1-4],我们把卟啉和手性相转移源连结起来,用奎宁-卟啉化合物作配体[5],考察其锰 配合物为催化剂对烯烃环氧化反应的催化性能。奎宁-卟啉锰 配合物结构式如下:1 实验部分1.1 试剂和仪器苯乙烯和α-甲基苯乙烯在氮气保护下减压蒸馏处理。氧源NaOCl的浓度由碘量法测定。其余试剂均为化学纯,色谱标样环氧苯乙烯和α-甲基环氧苯乙烯按文献[6]方法合成。奎宁-卟啉配体按文献[5]合成。260-50型红外光谱仪,KBr压片;UV-3000型紫外可见光谱仪,溶剂DMF;MT-3型CHN元素… 相似文献
4.
This paper describes a highly enantioselective epoxidation of alpha,beta-unsaturated esters using the fructose-derived ketone 2 as catalyst and Oxone as oxidant. High ee's have been obtained for a number of trans and trisubstituted substrates (82-98% ee). The results described show that it is feasible for dioxiranes to effectively epoxidize electron-deficient olefins with high ee's. 相似文献
5.
6.
7.
本文研究了试剂5-羧基偶氮胂I与铍的显色反应。试剂与铍在557nm形成1∶1络合物,其反应的酸度pH为5.3~6.2,毫克量级的干扰离子存在不干扰测定。该试剂可不加任何掩蔽剂,直接测定水样及锌基合成样中的铍。 相似文献
8.
9.
William R. Dolbier Jr. Yian Zhai Wei Xu Will Wheelus Florian Dulong Efram Goldberg Ion Ghiviriga Merle A. Battiste 《Journal of fluorine chemistry》2008,129(12):1133-1138
When 4-nitro-AF4 is treated with nucleophiles such as alkoxides and cyanide, a novel ring opening, cyclophane destroying reaction is observed whereby, via an SNAr mechanism, the nucleophile attacks the bridgehead aryl carbon vicinal to the nitro group with subsequent aryl-CF2 bond cleavage. 相似文献
10.
A series of chitosan-g-poly(acrylic acid)/biotite (CTS-g-PAA/BT) hydrogels with unique clay biotite (BT) were prepared and used to remove cationic dye methylene blue (MB) from aqueous
solution by batch adsorption experiments. Variables of the system including BT content, initial pH, contact time, initial
concentration, and temperature affecting the adsorption efficiency of MB by CTS-g-PAA/BT hydrogels were investigated. Kinetic studies indicated that the adsorption data well followed pseudo-second-order
kinetics. Langmuir and Freundlich isotherm models were applied to experimental equilibrium data of MB adsorption depending
on temperature. The adsorption equilibrium data obeyed Langmuir isotherm, and the monolayer adsorption capacity calculated
from the Langmuir isotherm was 2,125.70 mg/g for CTS-g-PAA/10% BT at 30 °C. The adsorption capacity was much higher compared with other hydrogels with the same content of other
clays. The introduction of BT into the hydrogel could effectively improve its adsorption properties and reduce the cost. Thermodynamic
parameters were evaluated for the dye-adsorbent systems and revealed that the adsorption process was spontaneous and exothermic
in nature. All the information gave an indication that CTS-g-PAA/10% BT could potentially be applied as an efficient adsorbent for cationic dye removal from aqueous solution. 相似文献