Individual modelling is a foundational approach to study the natural forest growth and in this paper, we develop a serial distance-depended individual tree model for some species in natural forest ...which would provide prediction and characteristics for natural species. The data used to develop individual model for natural mixed forests were collected from 712 remeasured 10-year periodic permanent sample plots of in Baihe Forest Bureau of Changbai Mountains, northeast China. Based on analyzing relationship between diameter increment of individual trees with tree size, competitive status, and site condition and finding out the major independent variables, the growth models for individual trees of 15 species in the natural mixed forests, that have good predicting precision, and easily applicable, were developed using stepwise regression method. The individual growth model developed in this study can reflect the tree increment of 15 species and be generally well suited for simulating tree and stand growth for natural mixed forests in Changbai Mountains. The research results for individual trees growth model of each species showed that main variable to influence on diameter increment of individual trees for natural mixed forests were tree size (D) and then competition index. The site condition was not related with diameter increment. The natural logarithm of DBH (lnD) and square diameter (D2) were included in the predicting models of diameter increment for all 15 species. The diameter increment was directly proportional to tree diameter for each species. For the competitive indexes in growth model, the relative diameter (RD), canopy closure (P), and the ratio of diameter of subject tree with maximum diameter (DDM) were related to diameter increment and the stand density measures were not significantly influenced on diameter increment. As canopy closure increase, tree increment decreases. The site conditions were performance less of factors in increment predictions in the model.
Cobalt in lithium-ion batteries Li, Matthew; Lu, Jun
Science (American Association for the Advancement of Science),
02/2020, Volume:
367, Issue:
6481
Journal Article
Peer reviewed
Replacements are sought for cobalt, a costly element used in lithium-ion battery cathodes
The use of cobalt in lithium-ion batteries (LIBs) traces back to the well-known LiCoO
2
(LCO) cathode, which ...offers high conductivity and stable structural stability throughout charge cycling. Compared to the other transition metals, cobalt is less abundant and more expensive and also presents political and ethical issues because of the way it is mined in Africa (
1
). Cheaper cathodes have been developed that substitute some of the cobalt with nickel and manganese, and LiNi
0.80
Co
0.15
Al
0.05
O
2
(NCA) and LiNi
1-
x-y
Co
x
Mn
y
O
2
(NMC, where
x
and
y
<1) are used in the majority of the LIBs in electric vehicles. Nonetheless, in NCA and NMC, cobalt enables high-rate performance and to some extent, enhances cycle stability. We outline research efforts that could further decrease or even eliminate cobalt content in LIBs to lower their cost while maintaining high performance.
Over the past 30 years, significant commercial and academic progress has been made on Li‐based battery technologies. From the early Li‐metal anode iterations to the current commercial Li‐ion ...batteries (LIBs), the story of the Li‐based battery is full of breakthroughs and back tracing steps. This review will discuss the main roles of material science in the development of LIBs. As LIB research progresses and the materials of interest change, different emphases on the different subdisciplines of material science are placed. Early works on LIBs focus more on solid state physics whereas near the end of the 20th century, researchers began to focus more on the morphological aspects (surface coating, porosity, size, and shape) of electrode materials. While it is easy to point out which specific cathode and anode materials are currently good candidates for the next‐generation of batteries, it is difficult to explain exactly why those are chosen. In this review, for the reader a complete developmental story of LIB should be clearly drawn, along with an explanation of the reasons responsible for the various technological shifts. The review will end with a statement of caution for the current modern battery research along with a brief discussion on beyond lithium‐ion battery chemistries.
The major development events in the history of lithium‐ion batteries are presented and the driving forces responsible for the various technological shifts are discussed.
A
bstract
We perform a systematical analysis of the
A
4
modular models with generalized CP for the masses and flavor mixing of quarks and leptons, and the most general form of the quark and lepton ...mass matrices is given. The CP invariance requires all couplings real in the chosen basis and thus the vacuum expectation value of the modulus
τ
uniquely breaks both the modular symmetry and CP symmetry. The phenomenologically viable models with minimal number of free parameters and the results of fit are presented. We find 20 models with 7 real free parameters that can accommodate the experimental data of lepton sector. We then apply
A
4
modular symmetry to the quark sector to explain quark masses and CKM mixing matrix, the minimal viable quark model is found to contain 10 free real parameters. Finally, we give two predictive quark-lepton unification models which use only 16 real free parameters to explain the flavor patterns of both quarks and leptons.
A compact two-antenna building block for forming the multiple-input multiple-output (MIMO) array in the mobile device such as the smartphone is presented. The building block has a planar structure of ...small size 7 × 10 mm 2 (about 0.08λ × 0.12λ) for operating at 3.5-GHz band (3.4-3.6 GHz), which is the recently identified frequency spectrum in World Radiocommunication Conference 2015 for future broadband mobile services. The building block is formed by two gap-coupled loop antennas having asymmetrically mirrored (AM) structures with respect to the system ground plane of the smartphone. The two AM antennas show good isolation thereof and their envelope correlation coefficient is much less than 0.1 in the operating band, showing very good independence of the two antennas in their far-field radiation characteristics. By using four such building blocks, an eight-antenna MIMO array at 3.5-GHz band in the smartphone is easily implemented. The channel capacity of the eight-antenna MIMO array in an 8 \× 8 MIMO system is calculated to be about 36 b/s/Hz with 20-dB signal-to-noise ratio. The measured channel capacity obtained using an 8 × 8 MIMO measurement setup is also presented, which generally agrees with the calculated results. The obtained eight-antenna MIMO array is promising for future or fifth-generation smartphone applications.
Unlike the revolutionary advances in the anodes of lithium-ion batteries from Li intercalation materials to Li alloy and/or conversion reaction materials, the development of the cathode is still ...dominated by the Li intercalation compounds. Transition metal ions are essential in these cathodes as the rapid redox reaction centers, and one of the biggest challenges for the TM-based cathodes is the capacity and power fading especially at an elevated temperature, which is directly associated with the dissolution-migration-deposition (DMD) process of TMs from the cathode materials. This process not only alters the surface structure of the cathode materials, but more importantly, changes the SEI composition at the anode side. There is no doubt that the TM-DMD issue should be addressed thoroughly to unlock the potential of these compounds to enable a prolonged battery lifetime. This review article mainly focuses on research activities with regard to the DMD process in TM-based cathode materials. In the first four sections, we choose Mn-based cathodes as an example to discuss how Mn DMD relates to the capacity fade of the cell, and what possible approaches might suppress the DMD process by modification of the electrode or electrolyte. In the fifth section, we discuss the TM DMD process in Ni-, Co-, Fe- and V-containing cathode materials. This article reviews the frontier electrochemical research on TM-based cathodes and summarizes the progress and challenges, thereby helping to advance future R&D of LIBs.
This paper reviews the research activities on the mechanistic understanding and solutions to overcome the TM DMD process, from the earliest discoveries to the latest progress.
This technical note presents necessary and sufficient conditions for the stability and stabilization of fractional-order interval systems. The results are obtained in terms of linear matrix ...inequalities. Two illustrative examples are given to show that our results are effective and less conservative for checking the robust stability and designing the stabilizing controller for fractional-order interval systems.
Objectives
Coronavirus disease 2019 (COVID‐19) is rapidly spreading worldwide. Lianhua Qingwen capsule (LQC) has shown therapeutic effects in patients with COVID‐19. This study is aimed to discover ...its molecular mechanism and provide potential drug targets.
Materials and Methods
An LQC target and COVID‐19–related gene set was established using the Traditional Chinese Medicine Systems Pharmacology database and seven disease‐gene databases. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and protein‐protein interaction (PPI) network were performed to discover the potential mechanism. Molecular docking was performed to visualize the patterns of interactions between the effective molecule and targeted protein.
Results
A gene set of 65 genes was generated. We then constructed a compound‐target network that contained 234 nodes of active compounds and 916 edges of compound‐target pairs. The GO and KEGG indicated that LQC can act by regulating immune response, apoptosis and virus infection. PPI network and subnetworks identified nine hub genes. The molecular docking was conducted on the most significant gene Akt1, which is involved in lung injury, lung fibrogenesis and virus infection. Six active compounds of LQC can enter the active pocket of Akt1, namely beta‐carotene, kaempferol, luteolin, naringenin, quercetin and wogonin, thereby exerting potential therapeutic effects in COVID‐19.
Conclusions
The network pharmacological strategy integrates molecular docking to unravel the molecular mechanism of LQC. Akt1 is a promising drug target to reduce tissue damage and help eliminate virus infection.
A Lianhua Qingwen capsule (LQC) target and COVID‐19 related gene set is established to construct compound‐target pharmacology network. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analysis indicate the regulating effect of LQC on apoptosis, antivirus, immune defense, and inflammatory response. Protein‐protein interaction network and critical subnetworks are constructed to identify hub gene target. The most significant gene, Akt 1, is selected to perform molecular docking with active compounds of LQC. Six compounds are finally recognized as potential anti‐COVID‐19 agents.
This note further investigates the locally and globally adaptive synchronization of an uncertain complex dynamical network. Several network synchronization criteria are deduced. Especially, our ...hypotheses and designed adaptive controllers for network synchronization are rather simple in form. It is very useful for future practical engineering design. Moreover, numerical simulations are also given to show the effectiveness of our synchronization approaches.
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