Ziyu Zeng - Academia.edu (original) (raw)
Papers by Ziyu Zeng
Norditerpenoid alkaloids are the main bioactive components of the medicinal plants of Aconitum an... more Norditerpenoid alkaloids are the main bioactive components of the medicinal plants of Aconitum and Delphinium. To achieve structure-activity relationship (SAR) studies of these natural products, especially of methyllycaconitine (MLA), investigation of their 3D structures is essential as the conformation of a molecule determines its bioactivities. NMR spectroscopic data (1 H, 13 C, COSY, HSQC, HMBC and NOESY) of 5 commercially available norditerpenoid alkaloid free bases and 2 of their salts (aconitine HCl and lappaconitine HBr) were obtained. It is notable that basic norditerpenoid alkaloids and their analogues are partially protonated at neutral pH, e.g. in plasma or water. Therefore, essential studies on the solution conformations of the two alkaloid salts, which are bioactive conformations, were carried out in D2O. Solution conformation of these alkaloids were investigated with NOESY spectroscopies and key 1 H signal coupling patterns. NMR analyses also demonstrated a rare through-space 1 H NMR effect of steric compression in synthetic [3.3.1]azabicyclic analogues of MLA. This effect is shown in norditerpenoid alkaloids with uncommonly small intensity compared with that in the synthetic analogues, suggesting there are conformational differences between the alkaloids and their synthetic analogues. Singlecrystal X-ray diffraction (XRD) is one of the best methods for investigating configuration and conformation, if such high quality crystals are available. 15 single-crystals of norditerpenoid alkaloids and their synthetic analogues were obtained in this work and used for determining their crystal conformations, and then their conformational common features were summarized. 13 C signal assignments reported in previous studies of the well-known lycoctonine, lappaconitine and crassicauline A norditerpenoid alkaloids are revised supported by 2D NMR spectroscopic data. Notably, a rare NMR effect of steric compression has been clearly demonstrated. Protonated norditerpenoid alkaloid salts adopt boat/chair conformations in crystals and in D2O, the same conformation of protonated [3.3.1]azabicycle in crystals, but that protonated [3.3.1]azabicycle adopts a chair/chair conformation in D2O.
European Journal of Medicinal Chemistry, 2022
Induction of apoptosis by the FDA-approved drug Venetoclax in cancer cells mainly derives from bl... more Induction of apoptosis by the FDA-approved drug Venetoclax in cancer cells mainly derives from blocking the interactions between BCL-2 and BH3-only proteins. Anti-apoptotic BFL-1, a homolog of BCL-2, also competitively binds to the BH3-only proteins and is responsible for Venetoclax-induced drug resistance. Compared to BCL-2, small-molecule inhibitors of BFL-1 are relatively underexplored. In order to tackle this issue, in-house compound library was screened and a hit compound was identified and optimized to obtain 12 (ZH97) functioning as a covalent and selective inhibitor of BFL-1. 12 modifies BFL-1 at the C55 residue, blocks BFL-1/BID interaction in vitro, promotes cellular cytochrome c release from mitochondria, and induced apoptosis in BFL-1 overexpressing cancer cells. Mechanistic studies show that 12 inhibited BFL-1/PUMA interaction in cell lysate and is effective in cancer cells that harboring high expression level of BFL-1. In summary, blockade of BFL-1/BH3-only proteins interactions with a covalent small-molecule inhibitor induced apoptosis and elicited antitumor activity. Thus, our study demonstrates an appealing strategy for selective modulation of cellular BFL-1 for cancer therapy.
2021 IEEE Sustainable Power and Energy Conference (iSPEC), 2021
With the massive construction of wind plants in the power system, the power balance is getting mo... more With the massive construction of wind plants in the power system, the power balance is getting more and more difficult to maintain because of the uncertainties bringing by wind power. However, the above problems can be greatly alleviated by introducing a variety of flexible resources such as cascaded hydropower system (CHS) and energy storage. Therefore, a stochastic optimal dispatching model considering CHS and energy storage is proposed. Further, participation of thermal power plants (TPPs) in deep peak regulation is considered in the model which can improve the flexibility of the grid. The proposed model is performed through a modified 24-node test system with the CHS in the Wujiang River. The numerical result shows that the proposed method can improve renewable energy accommodation.
2021 IEEE 5th Conference on Energy Internet and Energy System Integration (EI2), 2021
To cope with the energy crisis, environmental pollution, and global warming problem, the installe... more To cope with the energy crisis, environmental pollution, and global warming problem, the installed capacities of renewable energy are increasing rapidly. However, this trend has brought serious stability problems to the operation of the power systems, and huge flexible resources are needed to regulate the drastic fluctuations of wind and photovoilaic power generation. Cascaded hydropower system (CHS) is an excellent regulatory power source with great flexibility, thus this paper establishes a stochastic hydrothermal dispatching model considering CHS and renewable energy uncertainties. In addition, the deep peak shaving of thermal units is also considered. The effectiveness and the validity of the proposed model are verified using numerical examples based on the Wujiang River CHS in China.
Journal of Healthcare Engineering, 2022
In this study, we have used TCM medical record management platform and SAS statistical software t... more In this study, we have used TCM medical record management platform and SAS statistical software to analyze the cases of a professor in the treatment of type 2 diabetes, in order to explore the medication rules for the treatment of type 2 diabetes, so as to enrich and optimize the diagnosis and treatment plan for type 2 diabetes based on the experience of famous doctors. Chinese medicine treatment provides more diagnosis and treatment ideas. We have collected the professor’s treatment of type 2 diabetes, screened out 100 patients, from a total of 285 prescriptions, and entered them into the TCM medical record management platform. We used the TCM medical record management platform and SAS statistical software to analyze his professor’s experience in the treatment of type 2 diabetes. The medication analysis is as follows: (1) frequency of medication: 285 cases that met the inclusion criteria used a total of 187 traditional Chinese medicines. Among them, Salvia miltiorrhiza was used mos...
IEEE Transactions on Power Electronics, 2021
This letter assesses the impact of cyber-attacks on the control system of the Modular Multilevel ... more This letter assesses the impact of cyber-attacks on the control system of the Modular Multilevel Converter (MMC) based High-Voltage DC (MMC-HVDC) transmission technology. Specifically, the small-signal model of the MMC-HVDC is characterized by a closed-loop matrix and the distance to the small-signal instability is then quantified by structured pseudospectrum. Furthermore, a vertical search method is proposed to quantify the boundary of the structured pseudospectrum. The proposed quantification model with the vertical search method can be extended to the control of other power electronics-based systems. Case studies on a two-terminal MMC-HVDC system verify the effectiveness of the qualification method.
2021 13th International Conference on Machine Learning and Computing, 2021
One-shot face recognition is a challenging problem which requires recognizing novel identities fr... more One-shot face recognition is a challenging problem which requires recognizing novel identities from only one seen face image. One-shot classes are simply neglected because of the lack of training samples. Therefore, these classes contribute less to the improvement of face recognition performance. The main goal of one-shot face recognition task is to use the novel face samples to enhance the ability of network not only in close-set classify, but also in open-set face verification. In this paper, Base data and Novel data is trained separately with two classifiers to reduce the impact of data imbalance. We propose Confidence Constrain Loss to train classifiers in parallel and get better classifiers fusion in the test phase. Besides, we use data augmentation with 3D face reconstruction to obtain a variety of oneshot set's training samples. Thus, our method can effectively increase the recognition accuracy in the novel set without reducing recognition accuracy in base set. Experiment...
IEEE Transactions on Power Systems, 2021
The frequency security problem becomes a critical concern in power systems when the system inerti... more The frequency security problem becomes a critical concern in power systems when the system inertia is lowered due to the high penetration of renewable energy sources (RESs). A wind-storage system (WSS) controlled by power electronics can provide the virtual inertia to guarantee the fast frequency response after a disturbance. However, the provision of virtual inertia might be affected by the variability of wind power generation. To address this concern, we propose a two-stage chance-constrained stochastic optimization (TSCCSO) model to find the optimal thermal unit commitment (i.e., economic operation) and the optimal placement of virtual inertia (i.e., frequency stability) in a power grid using representative power system operation scenarios. An enhanced bilinear Benders decomposition method is employed with strong valid cuts to effectively solve the proposed optimization model. Numerical results on a practical power system show the effectiveness of the proposed model and solution method.
Natural Product Reports, 2021
This highlight focuses on norditerpenoid alkaloids from Aconitum and Delphinium where their struc... more This highlight focuses on norditerpenoid alkaloids from Aconitum and Delphinium where their structural differences result in pharmacological diversity that ranges from poisons to drugs.
2021 International Conference on Smart Energy Systems and Technologies (SEST), 2021
With a significant increase of load type and distributed generator permeability in multiple commu... more With a significant increase of load type and distributed generator permeability in multiple community integrated energy systems (CIESs), a hybrid distribution system (HDS) including AC/DC power network and heat network is required to satisfy multi-energy demands. This paper presents a detailed model for CIES and HDS to realize cascade utilization of multi-energy. To overcome the profit conflicts among HDS and multiple CIESs, a coordinated operation model based on hierarchical decentralized scheduling is proposed. Furthermore, the alternating direction method of multipliers (ADMM) algorithm is used to solve this coordinated model. Finally, the proposed model and method have been verified on a test HDS, which consists of an IEEE 33-bus AC power system coupling with a 4-bus DC power system and a 6-node heat system, and multiple CIESs which locate in Jiangsu Province, China.
2021 Power System and Green Energy Conference (PSGEC), 2021
Energy storages can significantly relieve the pressure of the power system brought by a large amo... more Energy storages can significantly relieve the pressure of the power system brought by a large amount of renewable energy generation. Under this situation, the risk assessment method becomes critical. In this paper, an explicit model for diverse energy storages with battery and Hydrogen Storage Systems (HSS) is built. Further, an optimal load shedding model by utilizing the sequential Monte Carlo (SMC) method is proposed to assess the risk of the power system with diverse energy storages. Then, the proposed method is test on a power system which is adapted from the IEEE 24-bus system. The numerical results show that diverse energy storages can improve risk assessment results of the power system.
![Research paper thumbnail of The 1H NMR Spectroscopic Effect of Steric Compression Is Found in [3.3.1]Oxa- and Azabicycles and Their Analogues](https://attachments.academia-assets.com/93609764/thumbnails/1.jpg)
](ACS Omega, 2021
The through-space 1 H NMR effect of steric compression by the lone-pair electrons of O-and N-atom... more The through-space 1 H NMR effect of steric compression by the lone-pair electrons of O-and N-atoms is shown in synthetic [3.3.1]oxa-and azabicycles. The electrons of the compressed proton bond are pushed away by the repulsive force generated by the lone-pair electrons of the heteroatom. There is a corresponding significant increase in the chemical shift of the compressed proton. The intensity of this deshielding effect is related to the proximity and overlap of the lone-pair or compressing atom. The steric compression decreases when the lone-pair electrons of the heteroatom and the compressed proton are not directly overlapped, for example, in [4.3.1]-and [3.2.1]azabicycles. Steric compression is also caused by a proton, deuterium, or an ethyl group close in space to the compressed proton. The protonated [3.3.1]azabicycle adopts a true-boat/true-chair conformation in its crystal lattice, but in solution the conformation is true-chair/true-chair.
Renewable and Sustainable Energy Reviews, 2021
Abstract The composition of worldwide energy consumption is undergoing tremendous changes due to ... more Abstract The composition of worldwide energy consumption is undergoing tremendous changes due to the consumption of non-renewable fossil energy and emerging global warming issues. Renewable energy is now the focus of energy development to replace traditional fossil energy. Energy storage system (ESS) is playing a vital role in power system operations for smoothing the intermittency of renewable energy generation and enhancing the system stability. We divide ESS technologies into five categories, mainly covering their development history, performance characteristics, and advanced materials. Biomass storage and gas storage are also discussed, which are not considered in most reviews. After detailed research, the rapid development of each technology in recent years is introduced, and some representative research works are surveyed. We comprehensively summarized the advantages and disadvantages of various ESS technologies and presented several evaluation indicators for quantitative analysis. Hybrid ESS is also considered based on the complex market demand. Then, we investigate the applications of various ESS technologies as short-term, medium-term, and long-term storages in power systems, covering the power generation, transmission and distribution, and end-user. Finally, this paper reviews global developing trends, and identifies critical challenges and promising opportunities.
European Journal of Organic Chemistry, 2021
1 H− 15 N HMBC spectra of norditerpenoid alkaloids and their synthetic azabicyclic analogues were... more 1 H− 15 N HMBC spectra of norditerpenoid alkaloids and their synthetic azabicyclic analogues were obtained to investigate the impacts of the through-space effect of steric compression, protonation, and formation of intramolecular hydrogen bonding on the 15 N NMR spectroscopy of these natural products and their piperidine-containing analogues. A rare 15 N NMR effect of steric compression is demonstrated in half-cage A/E-rings of norditerpenoid alkaloid free bases and their synthetic azabicyclic analogues, in which the distribution of the lone pair of electrons of the tertiary amine N-atom is sterically restricted by bridged cycloalkanes, e.g., cyclopentane, cyclohexane, and cycloheptane rings. This results in significant changes in the 15 N chemical shift, typically by at least ∼10 ppm. The lone pair of electrons of the N-atom in the piperidine ring are sterically compressed whether the bridged cyclohexane ring adopts a chair or boat conformation. The 15 N chemical shifts of 1α-OMe norditerpenoid alkaloid free bases significantly increase (Δδ N ≥ 15.6 ppm) on alkaloid protonation and thence the formation of an intramolecular hydrogen bond between N +-H and 1α-OMe. The intramolecular hydrogen bonds between the N-atom and 1α-OH of 1α-OH norditerpenoid alkaloid free bases, karacoline, condelphine, and neoline stabilize their A-rings, adopting an unusual twisted-boat conformation, and they also significantly increase δ N of the tertiary amine N-atom.
RSC Advances, 2020
The skeletal conformations of naturally occurring norditerpenoid alkaloids fix their substituent ... more The skeletal conformations of naturally occurring norditerpenoid alkaloids fix their substituent functional groups in space, thereby directing their bioactivities.
IEEE Transactions on Industry Applications, 2020
Norditerpenoid alkaloids are the main bioactive components of the medicinal plants of Aconitum an... more Norditerpenoid alkaloids are the main bioactive components of the medicinal plants of Aconitum and Delphinium. To achieve structure-activity relationship (SAR) studies of these natural products, especially of methyllycaconitine (MLA), investigation of their 3D structures is essential as the conformation of a molecule determines its bioactivities. NMR spectroscopic data (1 H, 13 C, COSY, HSQC, HMBC and NOESY) of 5 commercially available norditerpenoid alkaloid free bases and 2 of their salts (aconitine HCl and lappaconitine HBr) were obtained. It is notable that basic norditerpenoid alkaloids and their analogues are partially protonated at neutral pH, e.g. in plasma or water. Therefore, essential studies on the solution conformations of the two alkaloid salts, which are bioactive conformations, were carried out in D2O. Solution conformation of these alkaloids were investigated with NOESY spectroscopies and key 1 H signal coupling patterns. NMR analyses also demonstrated a rare through-space 1 H NMR effect of steric compression in synthetic [3.3.1]azabicyclic analogues of MLA. This effect is shown in norditerpenoid alkaloids with uncommonly small intensity compared with that in the synthetic analogues, suggesting there are conformational differences between the alkaloids and their synthetic analogues. Singlecrystal X-ray diffraction (XRD) is one of the best methods for investigating configuration and conformation, if such high quality crystals are available. 15 single-crystals of norditerpenoid alkaloids and their synthetic analogues were obtained in this work and used for determining their crystal conformations, and then their conformational common features were summarized. 13 C signal assignments reported in previous studies of the well-known lycoctonine, lappaconitine and crassicauline A norditerpenoid alkaloids are revised supported by 2D NMR spectroscopic data. Notably, a rare NMR effect of steric compression has been clearly demonstrated. Protonated norditerpenoid alkaloid salts adopt boat/chair conformations in crystals and in D2O, the same conformation of protonated [3.3.1]azabicycle in crystals, but that protonated [3.3.1]azabicycle adopts a chair/chair conformation in D2O.
European Journal of Medicinal Chemistry, 2022
Induction of apoptosis by the FDA-approved drug Venetoclax in cancer cells mainly derives from bl... more Induction of apoptosis by the FDA-approved drug Venetoclax in cancer cells mainly derives from blocking the interactions between BCL-2 and BH3-only proteins. Anti-apoptotic BFL-1, a homolog of BCL-2, also competitively binds to the BH3-only proteins and is responsible for Venetoclax-induced drug resistance. Compared to BCL-2, small-molecule inhibitors of BFL-1 are relatively underexplored. In order to tackle this issue, in-house compound library was screened and a hit compound was identified and optimized to obtain 12 (ZH97) functioning as a covalent and selective inhibitor of BFL-1. 12 modifies BFL-1 at the C55 residue, blocks BFL-1/BID interaction in vitro, promotes cellular cytochrome c release from mitochondria, and induced apoptosis in BFL-1 overexpressing cancer cells. Mechanistic studies show that 12 inhibited BFL-1/PUMA interaction in cell lysate and is effective in cancer cells that harboring high expression level of BFL-1. In summary, blockade of BFL-1/BH3-only proteins interactions with a covalent small-molecule inhibitor induced apoptosis and elicited antitumor activity. Thus, our study demonstrates an appealing strategy for selective modulation of cellular BFL-1 for cancer therapy.
2021 IEEE Sustainable Power and Energy Conference (iSPEC), 2021
With the massive construction of wind plants in the power system, the power balance is getting mo... more With the massive construction of wind plants in the power system, the power balance is getting more and more difficult to maintain because of the uncertainties bringing by wind power. However, the above problems can be greatly alleviated by introducing a variety of flexible resources such as cascaded hydropower system (CHS) and energy storage. Therefore, a stochastic optimal dispatching model considering CHS and energy storage is proposed. Further, participation of thermal power plants (TPPs) in deep peak regulation is considered in the model which can improve the flexibility of the grid. The proposed model is performed through a modified 24-node test system with the CHS in the Wujiang River. The numerical result shows that the proposed method can improve renewable energy accommodation.
2021 IEEE 5th Conference on Energy Internet and Energy System Integration (EI2), 2021
To cope with the energy crisis, environmental pollution, and global warming problem, the installe... more To cope with the energy crisis, environmental pollution, and global warming problem, the installed capacities of renewable energy are increasing rapidly. However, this trend has brought serious stability problems to the operation of the power systems, and huge flexible resources are needed to regulate the drastic fluctuations of wind and photovoilaic power generation. Cascaded hydropower system (CHS) is an excellent regulatory power source with great flexibility, thus this paper establishes a stochastic hydrothermal dispatching model considering CHS and renewable energy uncertainties. In addition, the deep peak shaving of thermal units is also considered. The effectiveness and the validity of the proposed model are verified using numerical examples based on the Wujiang River CHS in China.
Journal of Healthcare Engineering, 2022
In this study, we have used TCM medical record management platform and SAS statistical software t... more In this study, we have used TCM medical record management platform and SAS statistical software to analyze the cases of a professor in the treatment of type 2 diabetes, in order to explore the medication rules for the treatment of type 2 diabetes, so as to enrich and optimize the diagnosis and treatment plan for type 2 diabetes based on the experience of famous doctors. Chinese medicine treatment provides more diagnosis and treatment ideas. We have collected the professor’s treatment of type 2 diabetes, screened out 100 patients, from a total of 285 prescriptions, and entered them into the TCM medical record management platform. We used the TCM medical record management platform and SAS statistical software to analyze his professor’s experience in the treatment of type 2 diabetes. The medication analysis is as follows: (1) frequency of medication: 285 cases that met the inclusion criteria used a total of 187 traditional Chinese medicines. Among them, Salvia miltiorrhiza was used mos...
IEEE Transactions on Power Electronics, 2021
This letter assesses the impact of cyber-attacks on the control system of the Modular Multilevel ... more This letter assesses the impact of cyber-attacks on the control system of the Modular Multilevel Converter (MMC) based High-Voltage DC (MMC-HVDC) transmission technology. Specifically, the small-signal model of the MMC-HVDC is characterized by a closed-loop matrix and the distance to the small-signal instability is then quantified by structured pseudospectrum. Furthermore, a vertical search method is proposed to quantify the boundary of the structured pseudospectrum. The proposed quantification model with the vertical search method can be extended to the control of other power electronics-based systems. Case studies on a two-terminal MMC-HVDC system verify the effectiveness of the qualification method.
2021 13th International Conference on Machine Learning and Computing, 2021
One-shot face recognition is a challenging problem which requires recognizing novel identities fr... more One-shot face recognition is a challenging problem which requires recognizing novel identities from only one seen face image. One-shot classes are simply neglected because of the lack of training samples. Therefore, these classes contribute less to the improvement of face recognition performance. The main goal of one-shot face recognition task is to use the novel face samples to enhance the ability of network not only in close-set classify, but also in open-set face verification. In this paper, Base data and Novel data is trained separately with two classifiers to reduce the impact of data imbalance. We propose Confidence Constrain Loss to train classifiers in parallel and get better classifiers fusion in the test phase. Besides, we use data augmentation with 3D face reconstruction to obtain a variety of oneshot set's training samples. Thus, our method can effectively increase the recognition accuracy in the novel set without reducing recognition accuracy in base set. Experiment...
IEEE Transactions on Power Systems, 2021
The frequency security problem becomes a critical concern in power systems when the system inerti... more The frequency security problem becomes a critical concern in power systems when the system inertia is lowered due to the high penetration of renewable energy sources (RESs). A wind-storage system (WSS) controlled by power electronics can provide the virtual inertia to guarantee the fast frequency response after a disturbance. However, the provision of virtual inertia might be affected by the variability of wind power generation. To address this concern, we propose a two-stage chance-constrained stochastic optimization (TSCCSO) model to find the optimal thermal unit commitment (i.e., economic operation) and the optimal placement of virtual inertia (i.e., frequency stability) in a power grid using representative power system operation scenarios. An enhanced bilinear Benders decomposition method is employed with strong valid cuts to effectively solve the proposed optimization model. Numerical results on a practical power system show the effectiveness of the proposed model and solution method.
Natural Product Reports, 2021
This highlight focuses on norditerpenoid alkaloids from Aconitum and Delphinium where their struc... more This highlight focuses on norditerpenoid alkaloids from Aconitum and Delphinium where their structural differences result in pharmacological diversity that ranges from poisons to drugs.
2021 International Conference on Smart Energy Systems and Technologies (SEST), 2021
With a significant increase of load type and distributed generator permeability in multiple commu... more With a significant increase of load type and distributed generator permeability in multiple community integrated energy systems (CIESs), a hybrid distribution system (HDS) including AC/DC power network and heat network is required to satisfy multi-energy demands. This paper presents a detailed model for CIES and HDS to realize cascade utilization of multi-energy. To overcome the profit conflicts among HDS and multiple CIESs, a coordinated operation model based on hierarchical decentralized scheduling is proposed. Furthermore, the alternating direction method of multipliers (ADMM) algorithm is used to solve this coordinated model. Finally, the proposed model and method have been verified on a test HDS, which consists of an IEEE 33-bus AC power system coupling with a 4-bus DC power system and a 6-node heat system, and multiple CIESs which locate in Jiangsu Province, China.
2021 Power System and Green Energy Conference (PSGEC), 2021
Energy storages can significantly relieve the pressure of the power system brought by a large amo... more Energy storages can significantly relieve the pressure of the power system brought by a large amount of renewable energy generation. Under this situation, the risk assessment method becomes critical. In this paper, an explicit model for diverse energy storages with battery and Hydrogen Storage Systems (HSS) is built. Further, an optimal load shedding model by utilizing the sequential Monte Carlo (SMC) method is proposed to assess the risk of the power system with diverse energy storages. Then, the proposed method is test on a power system which is adapted from the IEEE 24-bus system. The numerical results show that diverse energy storages can improve risk assessment results of the power system.
ACS Omega, 2021
The through-space 1 H NMR effect of steric compression by the lone-pair electrons of O-and N-atom... more The through-space 1 H NMR effect of steric compression by the lone-pair electrons of O-and N-atoms is shown in synthetic [3.3.1]oxa-and azabicycles. The electrons of the compressed proton bond are pushed away by the repulsive force generated by the lone-pair electrons of the heteroatom. There is a corresponding significant increase in the chemical shift of the compressed proton. The intensity of this deshielding effect is related to the proximity and overlap of the lone-pair or compressing atom. The steric compression decreases when the lone-pair electrons of the heteroatom and the compressed proton are not directly overlapped, for example, in [4.3.1]-and [3.2.1]azabicycles. Steric compression is also caused by a proton, deuterium, or an ethyl group close in space to the compressed proton. The protonated [3.3.1]azabicycle adopts a true-boat/true-chair conformation in its crystal lattice, but in solution the conformation is true-chair/true-chair.
Renewable and Sustainable Energy Reviews, 2021
Abstract The composition of worldwide energy consumption is undergoing tremendous changes due to ... more Abstract The composition of worldwide energy consumption is undergoing tremendous changes due to the consumption of non-renewable fossil energy and emerging global warming issues. Renewable energy is now the focus of energy development to replace traditional fossil energy. Energy storage system (ESS) is playing a vital role in power system operations for smoothing the intermittency of renewable energy generation and enhancing the system stability. We divide ESS technologies into five categories, mainly covering their development history, performance characteristics, and advanced materials. Biomass storage and gas storage are also discussed, which are not considered in most reviews. After detailed research, the rapid development of each technology in recent years is introduced, and some representative research works are surveyed. We comprehensively summarized the advantages and disadvantages of various ESS technologies and presented several evaluation indicators for quantitative analysis. Hybrid ESS is also considered based on the complex market demand. Then, we investigate the applications of various ESS technologies as short-term, medium-term, and long-term storages in power systems, covering the power generation, transmission and distribution, and end-user. Finally, this paper reviews global developing trends, and identifies critical challenges and promising opportunities.
European Journal of Organic Chemistry, 2021
1 H− 15 N HMBC spectra of norditerpenoid alkaloids and their synthetic azabicyclic analogues were... more 1 H− 15 N HMBC spectra of norditerpenoid alkaloids and their synthetic azabicyclic analogues were obtained to investigate the impacts of the through-space effect of steric compression, protonation, and formation of intramolecular hydrogen bonding on the 15 N NMR spectroscopy of these natural products and their piperidine-containing analogues. A rare 15 N NMR effect of steric compression is demonstrated in half-cage A/E-rings of norditerpenoid alkaloid free bases and their synthetic azabicyclic analogues, in which the distribution of the lone pair of electrons of the tertiary amine N-atom is sterically restricted by bridged cycloalkanes, e.g., cyclopentane, cyclohexane, and cycloheptane rings. This results in significant changes in the 15 N chemical shift, typically by at least ∼10 ppm. The lone pair of electrons of the N-atom in the piperidine ring are sterically compressed whether the bridged cyclohexane ring adopts a chair or boat conformation. The 15 N chemical shifts of 1α-OMe norditerpenoid alkaloid free bases significantly increase (Δδ N ≥ 15.6 ppm) on alkaloid protonation and thence the formation of an intramolecular hydrogen bond between N +-H and 1α-OMe. The intramolecular hydrogen bonds between the N-atom and 1α-OH of 1α-OH norditerpenoid alkaloid free bases, karacoline, condelphine, and neoline stabilize their A-rings, adopting an unusual twisted-boat conformation, and they also significantly increase δ N of the tertiary amine N-atom.
RSC Advances, 2020
The skeletal conformations of naturally occurring norditerpenoid alkaloids fix their substituent ... more The skeletal conformations of naturally occurring norditerpenoid alkaloids fix their substituent functional groups in space, thereby directing their bioactivities.
IEEE Transactions on Industry Applications, 2020