Ni-Zn ferrite and Bi_(2)O_(3)composites were developed by the sol-gel method.The structural,magnetic,and dielectric properties were studied for all the prepared samples.X-ray diffraction(XRD)was performed to study the...Ni-Zn ferrite and Bi_(2)O_(3)composites were developed by the sol-gel method.The structural,magnetic,and dielectric properties were studied for all the prepared samples.X-ray diffraction(XRD)was performed to study the crystal structure.The results of field emission scanning electron microscopy(FE-SEM)showed that the addition of Bi_(2)O_(3)can increase the grain size of the Ni-Zn ferrite.Magnetic properties were analyzed by a hysteresis loop test and it was found that the saturation magnetization and coercivity decreased with the increase of Bi_(2)O_(3)ratio.In addition,the dielectric properties of the Ni-Zn ferrite were also improved with the addition of Bi_(2)O_(3).展开更多
Catalytic dehydrogenation,with its exceptional atom economy and chemoselectivity,offers a highly desirable yet challenging approach for converting multiple environmentally friendly alcohols into crucial molecules.Furt...Catalytic dehydrogenation,with its exceptional atom economy and chemoselectivity,offers a highly desirable yet challenging approach for converting multiple environmentally friendly alcohols into crucial molecules.Furthermore,the utilization of catalysts based on abundant elements found on Earth for alcohol dehydrogenation to produce acryl ketone holds significant promise as a versatile strategy in synthesizing key building blocks for numerous pharmaceutical applications.The present study describes a practical Co-catalyzed cascade dehydrogenative Claisen condensation of secondary alcohols with esters,facilitating the synthesis of a wide range of 3-hydroxy-prop-2-en-1-ones.We introduce a catalytic system based on novel and scalable indazole NNP-ligands coordinated to cobalt for efficient dehydrogenations of secondary alcohols,and propose a plausible reaction mechanism supported by control experiments and labeling studies.Notably,it allows for the streamlined synthesis of multiple pharmaceuticals in one-pot.展开更多
Rapid development of supercomputers and the prospect of quantum computers are posing increasingly serious threats to the security of communication.Using the principles of quantum mechanics,quantum communication offers...Rapid development of supercomputers and the prospect of quantum computers are posing increasingly serious threats to the security of communication.Using the principles of quantum mechanics,quantum communication offers provable security of communication and is a promising solution to counter such threats.Quantum secure direct communication(QSDC)is one important branch of quantum communication.In contrast to other branches of quantum communication,it transmits secret information directly.Recently,remarkable progress has been made in proof-of-principle experimental demonstrations of QSDC.However,it remains a technical feat to bring QSDC into a practical application.Here,we report the implementation of a practical quantum secure communication system.The security is analyzed in the Wyner wiretap channel theory.The system uses a coding scheme of concatenation of lowdensity parity-check(LDPC)codes and works in a regime with a realistic environment of high noise and high loss.The present system operates with a repetition rate of 1 MHz at a distance of 1.5 kilometers.The secure communication rate is 50 bps,sufficient to effectively send text messages and reasonably sized files of images and sounds.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11804006)the Natural Science Foundation of Shanxi Province,China(Grant Nos.201901D111126 and 201901D111117).
文摘Ni-Zn ferrite and Bi_(2)O_(3)composites were developed by the sol-gel method.The structural,magnetic,and dielectric properties were studied for all the prepared samples.X-ray diffraction(XRD)was performed to study the crystal structure.The results of field emission scanning electron microscopy(FE-SEM)showed that the addition of Bi_(2)O_(3)can increase the grain size of the Ni-Zn ferrite.Magnetic properties were analyzed by a hysteresis loop test and it was found that the saturation magnetization and coercivity decreased with the increase of Bi_(2)O_(3)ratio.In addition,the dielectric properties of the Ni-Zn ferrite were also improved with the addition of Bi_(2)O_(3).
基金supported by the National Natural Science Foundation of China(22002067,22202228)the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(20220052)+1 种基金the Science and Technology Project of Shanxi Province(202103021223457,202303021221256)Research Project Supported by Shanxi Scholarship Council of China.
文摘Catalytic dehydrogenation,with its exceptional atom economy and chemoselectivity,offers a highly desirable yet challenging approach for converting multiple environmentally friendly alcohols into crucial molecules.Furthermore,the utilization of catalysts based on abundant elements found on Earth for alcohol dehydrogenation to produce acryl ketone holds significant promise as a versatile strategy in synthesizing key building blocks for numerous pharmaceutical applications.The present study describes a practical Co-catalyzed cascade dehydrogenative Claisen condensation of secondary alcohols with esters,facilitating the synthesis of a wide range of 3-hydroxy-prop-2-en-1-ones.We introduce a catalytic system based on novel and scalable indazole NNP-ligands coordinated to cobalt for efficient dehydrogenations of secondary alcohols,and propose a plausible reaction mechanism supported by control experiments and labeling studies.Notably,it allows for the streamlined synthesis of multiple pharmaceuticals in one-pot.
基金supported by the National Basic Research Program of China under Grant Nos.2017YFA0303700 and 2015CB921001the National Natural Science Foundation of China under Grant Nos.61727801,11474181,61871257,and 11774197supported in part by the Beijing Advanced Innovation Center for Future Chip(ICFC).
文摘Rapid development of supercomputers and the prospect of quantum computers are posing increasingly serious threats to the security of communication.Using the principles of quantum mechanics,quantum communication offers provable security of communication and is a promising solution to counter such threats.Quantum secure direct communication(QSDC)is one important branch of quantum communication.In contrast to other branches of quantum communication,it transmits secret information directly.Recently,remarkable progress has been made in proof-of-principle experimental demonstrations of QSDC.However,it remains a technical feat to bring QSDC into a practical application.Here,we report the implementation of a practical quantum secure communication system.The security is analyzed in the Wyner wiretap channel theory.The system uses a coding scheme of concatenation of lowdensity parity-check(LDPC)codes and works in a regime with a realistic environment of high noise and high loss.The present system operates with a repetition rate of 1 MHz at a distance of 1.5 kilometers.The secure communication rate is 50 bps,sufficient to effectively send text messages and reasonably sized files of images and sounds.
