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81.
Aphrons containing di-(2-ethylhexyl)phosphoric acid (DEHPA) as an active substance were used for preconcentration of strontium from acetate buffers. Conditions for preparation of reasonably stable aphrons using non-ionic and anionic detergents in n-alkane and water mixture were found. After distribution of strontium, aphrons were separated from water solution by filtration with micro-filters. The separation efficiency was compared to the results obtained in liquid-liquid extraction of strontium with DEHPA in n-alkane. The results show that the preconcentration efficiency for strontium for aphrons is as good as for liquid-liquid extraction systems. 相似文献
82.
Phan Van Kiem Chau Van Minh Nguyen Xuan Nhiem Nguyen Thi Cuc Ngo Van Quang Hoang Le Tuan Anh Bui Huu Tai Pham Hai Yen Nguyen Thi Hoai Kim Young Ho Nanyoung Kim SeonJu Park Seung Hyun Kim 《Magnetic resonance in chemistry : MRC》2014,52(1-2):51-56
Seven new muurolane‐type sesquiterpenes, (4R,5R)‐muurol‐1(6),10(14)‐diene‐4,5‐diol (1), (4R,5R)‐muurol‐1(6)‐ene‐4,5‐diol (2), (4R,5R,10R)‐10‐methoxymuurol‐1(6)‐ene‐4,5‐diol (3), (4S)‐4‐hydroxy‐1,10‐seco‐muurol‐5‐ene‐1,10‐dione (4), (4R)‐4‐hydroxy‐1,10‐seco‐muurol‐5‐ene‐1,10‐dione (5), (6S,10S)‐6,10‐dihydroxy‐7,8‐seco‐2,8‐cyclo‐muurol‐4(5),7(11)‐diene‐12‐oic acid (6), and (6R,10S)‐6,10‐dihydroxy‐7,8‐seco‐2,8‐cyclo‐muurol‐4(5),7(11)‐diene‐12‐oic acid (7) were isolated from the marine sponge Dysidea cinerea. Their structures were determined by the combination of spectroscopic and chemical methods, including 1D‐NMR, 2D‐NMR, and CD spectra as well as by comparing the NMR data with those reported in the literature. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
83.
84.
Moore’s Law postulated that the number of transistors per chip would double roughly every 2 years. In parallel with the increased device density within a chip, there is an increased overall functionality. This trend can be seen in applications such as MEMS, RF circuits, where sensors, microactuators are integrated with digital and analog electronic components. This complexity leads to smaller bond pads on devices and packaging challenges. One of the requirements for the packages of image sensors and MEMS devices (such as RF- and AeroMEMS) or solar cells is the backside contact. The optical devices require an interface with environment without any restriction caused by the packages and on the other hand require a protection against the environment. Figure 1 shows main differences between IC package and package of an imaging sensor. In this paper, we discuss the two existing wafer-level-packaging technologies used already in mass production and give process details about our new WLP technology using via contacts between front end pads and redistribution. 相似文献
85.
Chiral porous hybrid solids for practical heterogeneous asymmetric hydrogenation of aromatic ketones 总被引:3,自引:0,他引:3
Chiral porous zirconium phosphonates containing Ru-BINAP-DPEN moieties were synthesized via a molecular building-block approach, and characterized by a variety of techniques including TGA, adsorption isotherms, XRD, SEM, IR, and microanalysis. These hybrid solids were used for enantioselective heterogeneous asymmetric hydrogenation of aromatic ketones with remarkably high ee values of up to 99.2%. These solid catalysts can also be easily recycled and reused for eight times without the loss of activity and enantioselectivity. Ready tunability of such a molecular building-block approach will allow the optimization of these hybrid materials and promise to lead to other practically useful heterogeneous asymmetric catalysts. 相似文献
86.
Polar phosphonic acid-derived Ru-BINAP systems were used to catalyze asymmetric hydrogenation of beta-keto esters in room temperature ionic liquids (RTILs) with complete conversions and ee values higher than those obtained from homogeneous reactions in MeOH (up to 99.3%), and were recycled by simple extraction and used for four times without the loss of activity and enantioselectivity. 相似文献
87.
A generalised finite difference scheme based on compact integrated radial basis function for flow in heterogeneous soils 下载免费PDF全文
D. Ngo‐Cong C. M. T. Tien T. Nguyen‐Ky D.‐A. An‐Vo N. Mai‐Duy D. V. Strunin T. Tran‐Cong 《国际流体数值方法杂志》2017,85(7):404-429
In the present paper, we develop a generalised finite difference approach based on compact integrated radial basis function (CIRBF) stencils for solving highly nonlinear Richards equation governing fluid movement in heterogeneous soils. The proposed CIRBF scheme enjoys a high level of accuracy and a fast convergence rate with grid refinement owing to the combination of the integrated RBF approximation and compact approximation where the spatial derivatives are discretised in terms of the information of neighbouring nodes in a stencil. The CIRBF method is first verified through the solution of ordinary differential equations, 2–D Poisson equations and a Taylor‐Green vortex. Numerical comparisons show that the CIRBF method outperforms some other methods in the literature. The CIRBF method in conjunction with a rational function transformation method and an adaptive time‐stepping scheme is then applied to simulate 1–D and 2–D soil infiltrations effectively. The proposed solutions are more accurate and converge faster than those of the finite different method used with a second‐order central difference scheme. Additionally, the present scheme also takes less time to achieve target accuracy in comparison with the 1D‐IRBF and higher order compact schemes. 相似文献
88.
89.
Nhi Tran Thi Y Cong Trinh Duc Hop Tran Thi Thanh Hai Luong Nhu Huu Nguyen The Tung Ngo Trinh 《Russian Journal of Applied Chemistry》2022,95(3):379-386
Russian Journal of Applied Chemistry - In this study, an optimized method for surface modification of cellulose microfibrils (CMF) with (3-Aminopropyl) trimethoxysilane (APTMS) for eco-friendly... 相似文献
90.
Ding Y Chen S Xu H Wang Z Zhang X Ngo TH Smet M 《Langmuir : the ACS journal of surfaces and colloids》2010,26(22):16667-16671
A CO(2)-responsive dispersant, N,N-dimethyl-N'-(pyren-1-ylmethyl) acetimidamidinium (PyAH(+)), which bears both a pyrene moiety and an amidinium cation, has been successfully synthesized. Through strong π-π interaction between the pyrene moiety and single-walled carbon nanotubes (SWNTs), we have demonstrated that PyAH(+) can be modified onto SWNT surfaces to promote the dispersion of SWNTs in water. Furthermore, taking advantage of gas triggered interconversions between the amidinium cation and amidine, reversible control on the solubility of SWNTs has been achieved simply through alternated bubbling of CO(2) and Ar. This work has demonstrated a new method for controlled dispersion and aggregation of SWNTs, and it may contribute to the development of gas responsive carbon materials. 相似文献