A simple formylation reaction of aryl halides, aryl triflates, and vinyl bromides under synergistic nickel‐ and organic‐dye‐mediated photoredox catalysis is reported. Distinct from widely used palladium‐catalyzed ...
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A simple formylation reaction of aryl halides, aryl triflates, and vinyl bromides under synergistic nickel‐ and organic‐dye‐mediated photoredox catalysis is reported. Distinct from widely used palladium‐catalyzed formylation processes, this reaction proceeds by a two‐step mechanistic sequence involving initial in situ generation of the diethoxymethyl radical from diethoxyacetic acid by a 4CzIPN‐mediated photoredox reaction. The formyl‐radical equivalent then undergoes nickel‐catalyzed substitution reactions with aryl halides and triflates and vinyl bromides to form the corresponding aldehyde products. Significantly, besides aryl bromides, less reactive aryl chlorides and triflates and vinyl halides serve as effective substrates for this process. Since the mild conditions involved in this reaction tolerate a plethora of functional groups, the process can be applied to the efficient preparation of diverse aromatic aldehydes.
With the increase of rotating speed, the rotor unbalance of the modern rotating machinery becomes more sensitive. The on-line active balance is an ideal balancing mode for precision machines. Electromagnetic balancer ...
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ISBN:
(纸本)9781509008223
With the increase of rotating speed, the rotor unbalance of the modern rotating machinery becomes more sensitive. The on-line active balance is an ideal balancing mode for precision machines. Electromagnetic balancer is a non-contact new-structure balancing device in the on-line balancing field, as it can reliably work in high-speed condition and keep the position balanceable after turning down. Balance ability is an important indicator evaluating the performance of a balancer. This paper studies a new electromagnetic balancer carrying permanent magnet for the motorized spindle. Because the counterweight disk is the primary moving element of the balancer, its balance compensation value and distribution are mainly discussed in this paper. Based on the existing disk structure, the balance ability of disks with different structure is researched. The two counterweight disks with the same compensation value and distribution angle, the two disks have the same compensation value and different distribution angles, the two disks have different compensation values and the same distribution angle are analysed. The calculation results demonstrate that the first scheme is proven better in the balance ability and can be easily developed.
Reported herein is a conceptually novel organocatalytic strategy for the formylation of boronic acids. New reactivity is engineered into the α‐amino‐acid‐forming Petasis reaction occurring between aryl boronic aci...
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Reported herein is a conceptually novel organocatalytic strategy for the formylation of boronic acids. New reactivity is engineered into the α‐amino‐acid‐forming Petasis reaction occurring between aryl boronic acids, amines, and glyoxylic acids to prepare aldehydes. The operational simplicity of the process and its ability to generate structurally diverse and valued aryl, heteroaryl, and α,β‐unsaturated aldehydes containing a wide array of functional groups, demonstrates the practical utility of the new synthetic strategy.
To improve the robustness of performance assessment for aileron actuators, a novel performance assessment for aileron actuators using multi-fractal detrended fluctuation analysis (MF-DFA) and self-organizing mapping (...
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ISBN:
(纸本)9781467384155
To improve the robustness of performance assessment for aileron actuators, a novel performance assessment for aileron actuators using multi-fractal detrended fluctuation analysis (MF-DFA) and self-organizing mapping (SOM) neural network is first proposed. First, a generalized regression neural network (GRNN) is employed to establish a fault observer, then the residue is generated by subtracting the actual actuator system output from the observer output. Second, the residue's feature is extracted by MF-DFA. Third, SOM neural network, trained only by the normal residue's feature, is used to obtain the minimum quantization error (MQE) between the current feature and the normal feature, and the health confidence value (CV) is obtained by normalizing MQE. Lastly, four types of faults, namely electronic amplifier gain abrupt change, electronic amplifier gain gradual change, sensor gain change and cylinder leakage, are applied to validate the effectiveness of the proposed method.
As the Three Mile Island and Chernobyl,the tragic Fukushima Dai-ichi Nuclear Power Plant accident occurring 4years ago has been the driving force to the safety improvement,its R&D and even for the next generation ...
As the Three Mile Island and Chernobyl,the tragic Fukushima Dai-ichi Nuclear Power Plant accident occurring 4years ago has been the driving force to the safety improvement,its R&D and even for the next generation *** NPIC there are three dominant R&D fields:1) Safety improvement after Fukushima accident includes SBO evaluation and improvement,Seismic Margin Assessment(SMA) based on risk information,development and implementation of Severe Accident Management Guidelines,Severe Accident Expert systems and etc.;2) R&D on nuclear safely covers fundamental research on key phenomena(*** degradation and reflooding,corium behaviour,hydrogen risks and etc.),Accident Tolerant Fuel(ATF),new methodology for coupling of PSA and deterministic safety analysis and etc.;3) design for GEN Ⅲ safely systems contains Cavity Injection system(CIS),Passive Removal system(PRS),passive containment cooling system and *** could be summarized that not only the safety of operating nuclear power plants and those under constructions has been enhanced due to these implements,but also the elaborative R&D are of significant value as the basement to finally achieve the practical elimination of large radioactive release.
It is difficulty for the MOC method based on Cell Modular Ray Tracing to deal with the irregular geometry such as the water gap between the PWR lattices. Hence, the neutron transport code NECP-Medlar based on Assembly...
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Taking the CSR1000 reactor as the research object, the SCAC-CSR1000 transient safety analysis code was made. The safety analysis of CSR1000 was done. The results showed that there is a flow reversal phenomenon in the ...
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China supercritical water cooled reactor CSR1000 is one of the fourth generation advanced reactors and is the first one which introduces passive safety system into the fourth generation reactor. Establish an analysis ...
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Face detection is one of the key technology for face information ***,face detection is mainly based on the RGB image,which might lead unexpected results when dealing with non-real 2-dimensional face,which printed on c...
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ISBN:
(纸本)9781509011964
Face detection is one of the key technology for face information ***,face detection is mainly based on the RGB image,which might lead unexpected results when dealing with non-real 2-dimensional face,which printed on clothes and *** work proposes a face detection approach based on features of depth *** used depth camera to obtain the raw depth data,and then mapped it to the 2D image combined with smooth image processing method to get the depth *** improved HOG-LBP algorithm was designed to profiling the features of face depth,and SVM-light was used for machine ***,an online video face detection system was accomplished.
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