A Simple Asymmetric Momentum Make SGD Greatest Again

We propose the simplest SGD enhanced method ever, Loss-Controlled Asymmetric Momentum(LCAM), aimed directly at the Saddle Point problem. Compared to the traditional SGD with Momentum, there's no increase in computational demand, yet it outperforms all current optimizers. We use the concepts of weight conjugation and traction effect to explain this phenomenon. We designed experiments to rapidly reduce the learning rate at specified epochs to trap parameters more easily at saddle points. We selected WRN28-10 as the test network and chose cifar10 and cifar100 as test datasets, an identical group to the original paper of WRN and Cosine Annealing Scheduling(CAS). We compared the ability to bypass saddle points of Asymmetric Momentum with different priorities. Finally, using WRN28-10 on Cifar100, we achieved a peak average test accuracy of 80.78\% around 120 epoch. For comparison, the original WRN paper reported 80.75\%, while CAS was at 80.42\%, all at 200 epoch. This means that while potentially increasing accuracy, we use nearly half convergence time. Our demonstration code is available at\\ https://github.com/hakumaicc/Asymmetric-Momentum-LCA

Cu doping effects on the electronic structure of Fe1-xCuxSe

Using angle-resolved photoemission spectroscopy (ARPES), we studied the evolution of the electronic structure of Fe1-xCuxSe from x = 0 to 0.10. We found that the Cu dopant introduces extra electron carriers. The hole bands near the gamma point are observed to steadily shift downward with increasing doping and completely sink down below the Fermi level (EF) for x > 0.05. Meanwhile, the electron pocket near the M point becomes larger but loses the spectral weight near EF. We also observed that effective mass of the electron band near the M point increases with doping. Our result explains why superconductivity disappears and metal insulator transition (MIT) like behavior occurs upon Cu doping in terms of electronic structure, and provide insight into emergent magnetic fluctuation in Fe1-xCuxSe

Highly-stable, flexible delivery of microjoule-level ultrafast pulses in vacuumized anti-resonant hollow-core fibers for active synchronization

We demonstrate the stable and flexible light delivery of multi-{\mu}J, sub-200-fs pulses over a ~10-m-long vacuumized anti-resonant hollow-core fiber (AR-HCF), which was successfully used for high-performance pulse synchronization. Compared with the pulse train launched into the AR-HCF, the transmitted pulse train out of the fiber exhibits excellent stabilities in pulse power and spectrum, with pointing stability largely improved. The walk-off between the fiber-delivery and the other free-space-propagation pulse trains, in an open loop, was measured to be <6 fs root-mean-square (RMS) over 90 minutes, corresponding to a relative optical-path variation of <2x10-7. This walk-off can be further suppressed to ~2 fs RMS simply using an active control loop, highlighting the great application potentials of this AR-HCF set-up in large-scale laser and accelerator facilities

Three-dimensional nanoscopy of whole cells and tissues with in situ point spread function retrieval

Single-molecule localization microscopy is a powerful tool for visualizing subcellular structures, interactions and protein functions in biological research. However, inhomogeneous refractive indices inside cells and tissues distort the fluorescent signal emitted from single-molecule probes, which rapidly degrades resolution with increasing depth. We propose a method that enables the construction of an in situ 3D response of single emitters directly from single-molecule blinking datasets, and therefore allows their locations to be pinpointed with precision that achieves the Cramér-Rao lower bound and uncompromised fidelity. We demonstrate this method, named in situ PSF retrieval (INSPR), across a range of cellular and tissue architectures, from mitochondrial networks and nuclear pores in mammalian cells to amyloid-β plaques and dendrites in brain tissues and elastic fibers in developing cartilage of mice. This advancement expands the routine applicability of super-resolution microscopy from selected cellular targets near coverslips to intra- and extracellular targets deep inside tissues

AI is a viable alternative to high throughput screening: a 318-target study

: High throughput screening (HTS) is routinely used to identify bioactive small molecules. This requires physical compounds, which limits coverage of accessible chemical space. Computational approaches combined with vast on-demand chemical libraries can access far greater chemical space, provided that the predictive accuracy is sufficient to identify useful molecules. Through the largest and most diverse virtual HTS campaign reported to date, comprising 318 individual projects, we demonstrate that our AtomNet® convolutional neural network successfully finds novel hits across every major therapeutic area and protein class. We address historical limitations of computational screening by demonstrating success for target proteins without known binders, high-quality X-ray crystal structures, or manual cherry-picking of compounds. We show that the molecules selected by the AtomNet® model are novel drug-like scaffolds rather than minor modifications to known bioactive compounds. Our empirical results suggest that computational methods can substantially replace HTS as the first step of small-molecule drug discovery

Synthesis and Characterization of Furan-Based Non-ionic Surfactants (FBNIOS)

A series of furan-based non-ionic surfactants (fbnios) derived from 5-(chloromethyl)furfural (5-CMF), a feedstock prepared by Origin Materials through a carbon negative process, were prepared from commercially available 2,5-bis(hydroxymethyl) furan (2,5-bisHMF). The fbnios were synthesized by alkylating one hydroxyl of 2,5-bisHMF by Williamson ether synthesis and ethoxylating the other hydroxyl to generate an oligo(ethylene oxide) (OEO). Through systematic variations in the OEO length achieved by anionic polymerization, and the use of octyl and dodecyl groups, fbnios with different hydrophilic-lipophilic balances (HLBs) were synthesized. The number-average degree of polymerization (DPn), and purity of the fbnios samples were determined by proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), and matrix-assisted laser desorption ionization-time of flight-mass spectroscopy (MALDI-ToF-MS). The amphiphilic properties of these fbnios were characterized by surface tension and fluorescence measurements. Surface tension was applied to determine the efficiency and effectiveness of the fbnios. The critical micelle concentration (CMC) of fbnios was determined by both characterization methods. The CMC of the fbnios prepared with an octyl chain was found to decrease about 3-fold upon increasing the DPn of the OEO block from 3 to 14. The length of the OEO block had less influence on the CMC of the fbnios series prepared with a dodecyl chain. In contrast, the alkyl chain used to prepare the fbnios was found to affect their CMC, the CMC of the fbnios with an octyl chain being more than one order of magnitude larger than the CMC of the fbnios with a dodecyl chain. The range of CMC values found for the fbnios prepared in this thesis covered the range of CMCs found for well-known non-ionic surfactants (nios) such as the Triton X or Brij surfactant families. The fbnios with a dodecyl chain were found to have lower CMCs than the Brij surfactants prepared with the same alkyl chain. In summary, fbnios appear to behave as typical nios and show promising amphiphilic properties

Bifurcation, chaos analysis and control in a discrete-time predator–prey system

Abstract The dynamical behavior of a discrete-time predator–prey model with modified Leslie–Gower and Holling’s type II schemes is investigated on the basis of the normal form method as well as bifurcation and chaos theory. The existence and stability of fixed points for the model are discussed. It is showed that under certain conditions, the system undergoes a Neimark–Sacker bifurcation when bifurcation parameter passes a critical value, and a closed invariant curve arises from a fixed point. Chaos in the sense of Marotto is also verified by both analytical and numerical methods. Furthermore, to delay or eliminate the bifurcation and chaos phenomena that exist objectively in this system, two control strategies are designed, respectively. Numerical simulations are presented not only to validate analytical results but also to show the complicated dynamical behavior

Dynamic behaviors of a discrete-time predator–prey bioeconomic system

Abstract Bifurcation and chaotic behavior of a discrete-time singular bioeconomic system are investigated. First, the traditional catch equation is modified after accounting for the handling time of the catch in a singular bioeconomic system. To discover the richer dynamics compared with the continuous form, the proposed system is considered difference scheme. Specially, the tangent space local parameterization condensed method for DAEs is generalized. The new local parameterization method is sufficiently general to be applicable to this type of discrete singular system. Also the dynamic behaviors of the system are investigated, by using normal form theory, center manifold theorem and bifurcation theory, it is shown that the system undergoes a Neimark–Sacker bifurcation and a flip bifurcation, on varying step-size in some range. In addition, numerical simulations are presented not only to illustrate our results with the theoretical analysis, but also to exhibit the complex dynamical behaviors