A concise total synthesis of novel monoterpenoid indole alkaloid(-)-voacafricine A is described,which proceeded in 14 longest linear steps and 5.2%overall yield.Key transformations comprised of(a)an organocatalyticall...A concise total synthesis of novel monoterpenoid indole alkaloid(-)-voacafricine A is described,which proceeded in 14 longest linear steps and 5.2%overall yield.Key transformations comprised of(a)an organocatalytically asymmetric Pictet-Spengler cyclization/lactamization cascade reaction generating the key tetracyclic lactam skeleton;(b)asymmetricα-alkylation of carbonyl group induced by Evans'chiral auxiliary with excellent diastereoselectivity;(c)a highly efficient one-pot desulfurization/hydrogenation/debenzylation transformation using Raney Ni under hydrogen atmosphere;as well as(d)an intramolecular Vorbürggen reaction constructing the quaternary ammonium motif and the final cagelike skeleton.展开更多
In this paper, the preparation technique of lavender essential oil microcapsules and the construction method of aromatic textiles were expounded, and the research status of bed curtains and lavender microcapsules at h...In this paper, the preparation technique of lavender essential oil microcapsules and the construction method of aromatic textiles were expounded, and the research status of bed curtains and lavender microcapsules at home and abroad was analyzed and studied from the perspective of application in textiles. The application of lavender essential oil to bed curtains through the microcapsule technique was put forward to allow lavender essential oil to play its role of helping sleep in bed curtains. This paper expounded the material selection and preparation technique of lavender microcapsule agents, and put forward the preparation method of microcapsules with mixed solutions of pure Chinese medicine extracts and natural essences as core material and high-viscosity epoxy resin as wall materials. The post-processing techniques and the spray ironing method for clothing were studied and developed, and these techniques and methods were applied to bed curtains, and good results were obtained.展开更多
Objective Motor control is encoded by neuronal activity. Small conductance Ca2＋-activated K＋ channels （SK channels） maintain the regularity and precision of firing by contributing to the afterhyperpolarization （...Objective Motor control is encoded by neuronal activity. Small conductance Ca2＋-activated K＋ channels （SK channels） maintain the regularity and precision of firing by contributing to the afterhyperpolarization （AHP） of the action potential in mammals. However, it is not clear how SK channels regulate the output of the vocal motor system in songbirds. The premotor robust nucleus of the arcopallium （RA） in the zebra finch is responsible for the output of song information. The temporal pattern of spike bursts in RA projection neurons is associated with the timing of the acoustic features of birdsong. Methods The firing properties of RA projection neurons were analyzed using patch clamp whole-cell and cell-attached recording techniques. Results SK channel blockade by apamin decreased the AHP amplitude and increased the evoked firing rate in RA projection neurons. It also caused reductions in the regularity and precision of firing. RA projection neurons displayed regular spontaneous action potentials, while apamin caused irregular spontaneous firing but had no effect on the firing rate. In the absence of synaptic inputs, RA projection neurons still had spontaneous firing, and apamin had an evident effect on the firing rate, but caused no significant change in the firing regularity, compared with apamin application in the presence of synaptic inputs. Conclusion SK channels contribute to the maintenance of firing regularity in RA projection neurons which requires synaptic activity, and consequently ensures the precision of song encoding.展开更多
Continuing investigation of Delphinium souliei Franch yielded two minor new diterpenoid alkaloids--souline E(1) and souline F(2), their structures were determined on the basis of spectroscopic evidences.
The phytochemical investigation of Delphinium tongolense Franch. yielded two new diterpenoid alkaloids tongolenine C and tongolenine D. Their structures were elucidated by spectroscopical methods.
With the atomically sharp interface and stable switching channel, van der Waals(vdW) heterostructure memristors have attracted extensive interests for the application of high-density memory and neuromorphic computing....With the atomically sharp interface and stable switching channel, van der Waals(vdW) heterostructure memristors have attracted extensive interests for the application of high-density memory and neuromorphic computing. Here, we demonstrate a new type of vdW heterostructure memristor device by sandwiching a single-crystalline h-BN layer between two thin graphites. In such a device, a stable bipolar resistive switching(RS) behavior has been observed for the first time. We also characterize their switching performance, and observe an on/off ratio of >10^(3) and a minimum RESET voltage variation coefficient of3.81%. Our work underscores the potential of 2D materials and vdW heterostructures for emerging memory and neuromorphic applications.展开更多
Two-dimensional(2D)van der Waals heterostructure(vdWH)-based floating gate devices show great potential for next-generation nonvolatile and multilevel data storage memory.However,high program voltage induced substanti...Two-dimensional(2D)van der Waals heterostructure(vdWH)-based floating gate devices show great potential for next-generation nonvolatile and multilevel data storage memory.However,high program voltage induced substantial energy consumption,which is one of the primary concerns,hinders their applications in lowenergy-consumption artificial synapses for neuromorphic computing.In this study,we demonstrate a three-terminal floating gate device based on the vdWH of tin disulfide(SnS2),hexagonal boron nitride(h-BN),and few-layer graphene.The large electron affinity of SnS2 facilitates a significant reduction in the program voltage of the device by lowering the hole-injection barrier across h-BN.Our floating gate device,as a nonvolatile multilevel electronic memory,exhibits large on/off current ratio(105),good retention(over 104 s),and robust endurance(over 1000 cycles).Moreover,it can function as an artificial synapse to emulate basic synaptic functions.Further,low energy consumption down to7 picojoule(pJ)can be achieved owing to the small program voltage.High linearity(<1)and conductance ratio(80)in long-term potentiation and depression(LTP/LTD)further contribute to the high pattern recognition accuracy(90%)in artificial neural network simulation.The proposed device with attentive band engineering can promote the future development of energy-efficient memory and neuromorphic devices.展开更多
Neuromorphic intelligent hardware technologies have undergone rapid advancement during the past decade,with the goal of building intelligent devices and systems capable of overcoming challenges associated with convent...Neuromorphic intelligent hardware technologies have undergone rapid advancement during the past decade,with the goal of building intelligent devices and systems capable of overcoming challenges associated with conventional hardware.Realization of neuromorphic intelligent hardware depends on major advances in materials science,condensed matter physics,device physics and engineering.As a revolutionary discovery,two-dimensional(2D)materials with atomically-thin thickness and exceptionally high tunability introduce a new physical paradigm and show great promise in the development of intelligent devices.Here,we give prominence to three categories of tunable properties(i.e.,charge carrier,band structure,lattice structure)that are inherent for 2D materials and review their superiorities in constructing intelligent devices particularly in electronics and optoelectronics.Furthermore,we provide insight into how the unique physical mechanisms emerging in 2D materials offer a fertile ground for the design of diverse intelligence devices.展开更多
Emulation of advanced synaptic functions of the human brain with electronic devices contributes an important step toward constructing high‐efficiency neuromorphic systems.Ferroelectric materials are promising candida...Emulation of advanced synaptic functions of the human brain with electronic devices contributes an important step toward constructing high‐efficiency neuromorphic systems.Ferroelectric materials are promising candidates as synaptic weight elements in neural network hardware due to their controllable polarization states.However,the increased depolarization field at the na-noscale and the complex fabrication process of the traditional ferroelectric materials hamper the development of high‐density,low‐power,and highly sensitive synaptic devices.Here,we report the implementation of two‐dimensional(2D)ferroelectricα‐In_(2)Se_(3)as an active channel material to emulate typical synaptic functions.Theα‐In_(2)Se_(3)‐based synaptic device fea-tures multimode operations,enabled by the coupled ferroelectric polarization under various voltage pulses applied at both drain and gate terminals.Moreover,the energy consumption can be reduced to~1 pJ by using high‐κdielectric(Al2O3).The successful control of ferroelectric polarizations inα‐In_(2)Se_(3)and its application in artificial synapses are expected to inspire the implementation of 2D ferroelectric materials for future neuromorphic systems.展开更多
基金supported by Beijing Key Laboratory of Active Substance Discovery and Druggability Evaluation,CAMS Innovation Fund for Medical Sciences(CIFMS,No.2022-I2M-3–002)。
文摘A concise total synthesis of novel monoterpenoid indole alkaloid(-)-voacafricine A is described,which proceeded in 14 longest linear steps and 5.2%overall yield.Key transformations comprised of(a)an organocatalytically asymmetric Pictet-Spengler cyclization/lactamization cascade reaction generating the key tetracyclic lactam skeleton;(b)asymmetricα-alkylation of carbonyl group induced by Evans'chiral auxiliary with excellent diastereoselectivity;(c)a highly efficient one-pot desulfurization/hydrogenation/debenzylation transformation using Raney Ni under hydrogen atmosphere;as well as(d)an intramolecular Vorbürggen reaction constructing the quaternary ammonium motif and the final cagelike skeleton.
基金Supported by Undergraduate Training Program for Innovation and Entrepreneurship of Guangxi University of Chinese Medicine in 2023(S202310600084)。
文摘In this paper, the preparation technique of lavender essential oil microcapsules and the construction method of aromatic textiles were expounded, and the research status of bed curtains and lavender microcapsules at home and abroad was analyzed and studied from the perspective of application in textiles. The application of lavender essential oil to bed curtains through the microcapsule technique was put forward to allow lavender essential oil to play its role of helping sleep in bed curtains. This paper expounded the material selection and preparation technique of lavender microcapsule agents, and put forward the preparation method of microcapsules with mixed solutions of pure Chinese medicine extracts and natural essences as core material and high-viscosity epoxy resin as wall materials. The post-processing techniques and the spray ironing method for clothing were studied and developed, and these techniques and methods were applied to bed curtains, and good results were obtained.
基金supported by grants from the National Natural Science Foundation of China (30970363 and 31172092)
文摘Objective Motor control is encoded by neuronal activity. Small conductance Ca2＋-activated K＋ channels （SK channels） maintain the regularity and precision of firing by contributing to the afterhyperpolarization （AHP） of the action potential in mammals. However, it is not clear how SK channels regulate the output of the vocal motor system in songbirds. The premotor robust nucleus of the arcopallium （RA） in the zebra finch is responsible for the output of song information. The temporal pattern of spike bursts in RA projection neurons is associated with the timing of the acoustic features of birdsong. Methods The firing properties of RA projection neurons were analyzed using patch clamp whole-cell and cell-attached recording techniques. Results SK channel blockade by apamin decreased the AHP amplitude and increased the evoked firing rate in RA projection neurons. It also caused reductions in the regularity and precision of firing. RA projection neurons displayed regular spontaneous action potentials, while apamin caused irregular spontaneous firing but had no effect on the firing rate. In the absence of synaptic inputs, RA projection neurons still had spontaneous firing, and apamin had an evident effect on the firing rate, but caused no significant change in the firing regularity, compared with apamin application in the presence of synaptic inputs. Conclusion SK channels contribute to the maintenance of firing regularity in RA projection neurons which requires synaptic activity, and consequently ensures the precision of song encoding.
文摘Continuing investigation of Delphinium souliei Franch yielded two minor new diterpenoid alkaloids--souline E(1) and souline F(2), their structures were determined on the basis of spectroscopic evidences.
文摘The phytochemical investigation of Delphinium tongolense Franch. yielded two new diterpenoid alkaloids tongolenine C and tongolenine D. Their structures were elucidated by spectroscopical methods.
基金supported by Laboratory of Solid State Microstructures,Nanjing University(M34049)the Jiangsu Postdoctoral Research Funding Program under Grant No.2021K451C。
文摘With the atomically sharp interface and stable switching channel, van der Waals(vdW) heterostructure memristors have attracted extensive interests for the application of high-density memory and neuromorphic computing. Here, we demonstrate a new type of vdW heterostructure memristor device by sandwiching a single-crystalline h-BN layer between two thin graphites. In such a device, a stable bipolar resistive switching(RS) behavior has been observed for the first time. We also characterize their switching performance, and observe an on/off ratio of >10^(3) and a minimum RESET voltage variation coefficient of3.81%. Our work underscores the potential of 2D materials and vdW heterostructures for emerging memory and neuromorphic applications.
基金National Natural Science Foundation of China,Grant/Award Numbers:U2032147,21872100Singapore MOE Grant,Grant/Award Number:MOE-2019-T2-1-002the Science and Engineering Research Council of A*STAR(Agency for Science,Technology and Research)Singapore,Grant/Award Number:A20G9b0135。
文摘Two-dimensional(2D)van der Waals heterostructure(vdWH)-based floating gate devices show great potential for next-generation nonvolatile and multilevel data storage memory.However,high program voltage induced substantial energy consumption,which is one of the primary concerns,hinders their applications in lowenergy-consumption artificial synapses for neuromorphic computing.In this study,we demonstrate a three-terminal floating gate device based on the vdWH of tin disulfide(SnS2),hexagonal boron nitride(h-BN),and few-layer graphene.The large electron affinity of SnS2 facilitates a significant reduction in the program voltage of the device by lowering the hole-injection barrier across h-BN.Our floating gate device,as a nonvolatile multilevel electronic memory,exhibits large on/off current ratio(105),good retention(over 104 s),and robust endurance(over 1000 cycles).Moreover,it can function as an artificial synapse to emulate basic synaptic functions.Further,low energy consumption down to7 picojoule(pJ)can be achieved owing to the small program voltage.High linearity(<1)and conductance ratio(80)in long-term potentiation and depression(LTP/LTD)further contribute to the high pattern recognition accuracy(90%)in artificial neural network simulation.The proposed device with attentive band engineering can promote the future development of energy-efficient memory and neuromorphic devices.
基金supported by the National Natural Science Foundation of China(Grant Nos.62122036,62034004,61921005,61974176,6220411012074176)+4 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20220775)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB44000000)the National Key R&D Program of China(Grant Nos.2019YFB2205400,and 2019YFB2205402)the Fundamental Research Funds for the Central Universities(Grant No.020414380179)the support from the AIQ foundation。
文摘Neuromorphic intelligent hardware technologies have undergone rapid advancement during the past decade,with the goal of building intelligent devices and systems capable of overcoming challenges associated with conventional hardware.Realization of neuromorphic intelligent hardware depends on major advances in materials science,condensed matter physics,device physics and engineering.As a revolutionary discovery,two-dimensional(2D)materials with atomically-thin thickness and exceptionally high tunability introduce a new physical paradigm and show great promise in the development of intelligent devices.Here,we give prominence to three categories of tunable properties(i.e.,charge carrier,band structure,lattice structure)that are inherent for 2D materials and review their superiorities in constructing intelligent devices particularly in electronics and optoelectronics.Furthermore,we provide insight into how the unique physical mechanisms emerging in 2D materials offer a fertile ground for the design of diverse intelligence devices.
基金Ministry of Education—Singapore,Grant/Award Number:MOE‐2019‐T2‐1‐002National Natural Science Foundation of China,Grant/Award Numbers:21872100,U2032147Agency for Science,Technology and Research,Grant/Award Numbers:A1938c0035,A20G9b0135。
文摘Emulation of advanced synaptic functions of the human brain with electronic devices contributes an important step toward constructing high‐efficiency neuromorphic systems.Ferroelectric materials are promising candidates as synaptic weight elements in neural network hardware due to their controllable polarization states.However,the increased depolarization field at the na-noscale and the complex fabrication process of the traditional ferroelectric materials hamper the development of high‐density,low‐power,and highly sensitive synaptic devices.Here,we report the implementation of two‐dimensional(2D)ferroelectricα‐In_(2)Se_(3)as an active channel material to emulate typical synaptic functions.Theα‐In_(2)Se_(3)‐based synaptic device fea-tures multimode operations,enabled by the coupled ferroelectric polarization under various voltage pulses applied at both drain and gate terminals.Moreover,the energy consumption can be reduced to~1 pJ by using high‐κdielectric(Al2O3).The successful control of ferroelectric polarizations inα‐In_(2)Se_(3)and its application in artificial synapses are expected to inspire the implementation of 2D ferroelectric materials for future neuromorphic systems.
