3,141 research outputs found
Development of positioning jig for glass capillary bending mechanism
In a bending mechanism for glass capillary, the positioning jig to hold the capillary in place is one of the most important components to ensure the bending quality. The tapered shoulder of the capillary is used as the positioning reference. Since the dimension of the shoulder of individual capillaries varies slightly, the geometry of the capillaries is studied to identify the desired positioning spot on the shoulder. Upon determination of the positioning spot, a positioning jig is designed, which is composed of positioning, holding, and clamping units. A prototype is made and assembled onto the bending mechanism for testing. The testing results show that the mechanism is able to achieve the desired functionalities demanded by the delicate bending process.<br /
Assessing Electricity Service Unfairness with Transfer Counterfactual Learning
Energy justice is a growing area of interest in interdisciplinary energy
research. However, identifying systematic biases in the energy sector remains
challenging due to confounding variables, intricate heterogeneity in
counterfactual effects, and limited data availability. First, this paper
demonstrates how one can evaluate counterfactual unfairness in a power system
by analyzing the average causal effect of a specific protected attribute.
Subsequently, we use subgroup analysis to handle model heterogeneity and
introduce a novel method for estimating counterfactual unfairness based on
transfer learning, which helps to alleviate the data scarcity in each subgroup.
In our numerical analysis, we apply our method to a unique large-scale
customer-level power outage data set and investigate the counterfactual effect
of demographic factors, such as income and age of the population, on power
outage durations. Our results indicate that low-income and elderly-populated
areas consistently experience longer power outages under both daily and
post-disaster operations, and such discrimination is exacerbated under severe
conditions. These findings suggest a widespread, systematic issue of injustice
in the power service systems and emphasize the necessity for focused
interventions in disadvantaged communities.Comment: The preliminary version titled "Detecting Electricity Service Equity
Issues with Transfer Counterfactual Learning on Large-Scale Outage Datasets"
is presented at NeurIPS 2023 Workshops on Causal Representation Learning
(CRL) and Algorithmic Fairness through the Lens of Time (AFT); See v
Blockage of transdifferentiation from fibroblast to myofibroblast in experimental ovarian cancer models
<p>Abstract</p> <p>Background</p> <p>Tumour stromal myofibroblasts can promote tumour invasion. As these cells are genetically more stable than cancer cells, there has been enormous interest in developing targeted molecular therapies against them. Chloride intracellular channel 4 (CLIC4) and reactive oxygen species (ROS) have been linked with promoting stromal cell transdifferentiation in various cancers, but little is known of their roles in ovarian cancer. In this study, we examined the functional roles that both CLIC4 and ROS play in the process of ovarian cancer cell-stimulated or TGF-β1 induced fibroblast-to-myofibroblast transdifferentiation. We also examine whether it is possible to reverse such a process, with the aim of developing novel therapies against ovarian cancer by targeting activated transdifferentiated myofibroblasts.</p> <p>Results</p> <p>We demonstrate that TGF-β1 induced or CM<sup>SKOV3 </sup>activate transdifferentiated myofibroblasts (fibroblasts). These fibroblasts mimic "reactive" stromal myofibroblasts and demonstrate significant up-regulation of CLIC4 expression and increased level of ROS production. Blocking the production of ROS with an antioxidant consequently reduces the expression of CLIC4, and is accompanied by disappearance of <it>α</it>-smooth-muscle actin (α-SMA), a myofibroblast marker, suggesting ROS acts as a signalling molecule that promotes and enhances CLIC4 activities in the myofibroblast transdifferentiaton process. Down-regulation of CLIC4 with a generic agent or specific siRNA both significantly reduces the expression of factors related to the phenotypes and functions of myofibroblasts, such as α-SMA, hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF), thus reversing the myofibroblast phenotype back to fibroblasts. These results convincingly show that ROS and CLIC4 are responsible for TGF-β1 induced fibroblast-to-myofibroblast transdifferentiaton and down-regulation of both is sufficient to block transdifferentiated myofibroblasts.</p> <p>Conclusion</p> <p>Molecular targeting of ROS and CLIC4 has the potential to develop novel therapies for ovarian cancer.</p
M-estimation in Low-rank Matrix Factorization: a General Framework
Many problems in science and engineering can be reduced to the recovery of an unknown large matrix from a small number of random linear measurements. Matrix factorization arguably is the most popular approach for low-rank matrix recovery. Many methods have been proposed using different loss functions, for example the most widely used L_2 loss, more robust choices such as L_1 and Huber loss, quantile and expectile loss for skewed data. All of them can be unified into the framework of M-estimation. In this paper, we present a general framework of low-rank matrix factorization based on M-estimation in statistics. The framework mainly involves two steps: firstly we apply Nesterov's smoothing technique to obtain an optimal smooth approximation for non-smooth loss function, such as L_1 and quantile loss; secondly we exploit an alternative updating scheme along with Nesterov's momentum method at each step to minimize the smoothed loss function. Strong theoretical convergence guarantee has been developed for the general framework, and extensive numerical experiments have been conducted to illustrate the performance of proposed algorithm
Gallium-Doped Li7La3Zr2O12 Garnet-Type Electrolytes with High Lithium-Ion Conductivity
Owing to their high conductivity, crystalline Li7–3xGaxLa3Zr2O12 garnets are promising electrolytes for all-solid-state lithium-ion batteries. Herein, the influence of Ga doping on the phase, lithium-ion distribution, and conductivity of Li7–3xGaxLa3Zr2O12 garnets is investigated, with the determined concentration and mobility of lithium ions shedding light on the origin of the high conductivity of Li7–3xGaxLa3Zr2O12. When the Ga concentration exceeds 0.20 Ga per formula unit, the garnet-type material is found to assume a cubic structure, but lower Ga concentrations result in the coexistence of cubic and tetragonal phases. Most lithium within Li7–3xGaxLa3Zr2O12 is found to reside at the octahedral 96h site, away from the central octahedral 48g site, while the remaining lithium resides at the tetrahedral 24d site. Such kind of lithium distribution leads to high lithium-ion mobility, which is the origin of the high conductivity; the highest lithium-ion conductivity of 1.46 mS/cm at 25 °C is found to be achieved for Li7–3xGaxLa3Zr2O12 at x = 0.25. Additionally, there are two lithium-ion migration pathways in the Li7–3xGaxLa3Zr2O12 garnets: 96h-96h and 24d-96h-24d, but the lithium ions transporting through the 96h-96h pathway determine the overall conductivity
Experimental Study on Damage Breakage Properties of Shaft Lining Concrete under Hydromechanical Coupling
Shaft lining concrete is exposed to a long-term coupled effect of a complex stress environment and high underground water pressure. To study the damage breakage properties under the above specific working conditions, shaft lining concrete specimens meeting the requirements of engineering application were prepared. The triaxial hydraulic coupling permeability test was conducted, and the designed osmotic pressures were 4 MPa, 6 MPa, 8 MPa, and 10 MPa. The results show that as osmotic pressure increases, the peak strength of shaft lining concrete decreases gradually, the surface cracks of specimen increase, and the failure mode is oblique shear failure. According to variation characteristics of permeability-strain and stress-strain curves of shaft lining concrete during loading, it is divided into three stages: compaction stage, sudden increase of permeability stage, and postpeak permeability change stage. In addition, the constitutive model of the shaft lining concrete with the influence of confining pressure and osmotic pressure was established, and the theoretical curve is in good agreement with the test curve. The damage evolution model shows that damage threshold of shaft lining concrete occurs earlier than that of ordinary concrete because of the influence of permeable water, and the damage development of the strain softening stage is particularly rapid
Site-specific Forest-assembly of Single-Wall Carbon Nanotubes on Electron-beam Patterned SiOx/Si Substrates
Based on electron-beam direct writing on the SiOx/Si substrates, favorable
absorption sites for ferric cations (Fe3+ ions) were created on the surface
oxide layer. This allowed Fe3+-assisted self-assembled arrays of single-wall
carbon nanotube (SWNT) probes to be produced. Auger investigation indicated
that the incident energetic electrons depleted oxygen, creating more dangling
bonds around Si atoms at the surface of the SiOx layer. This resulted in a
distinct difference in the friction forces from unexposed regions as measured
by lateral force microscopy (LFM). Atomic force microscopy (AFM) affirmed that
the irradiated domains absorbed considerably more Fe3+ ions upon immersion into
pH 2.2 aqueous FeCl3 solution. This rendered a greater yield of FeO(OH)/FeOCl
precipitates, primarily FeO(OH), upon subsequent washing with lightly basic
dimethylformamide (DMF) solution. Such selective metalfunctionalization
established the basis for the subsequent patterned forest-assembly of SWNTs as
demonstrated by resonance Raman spectroscopy
Predicting Multi-Codebook Vector Quantization Indexes for Knowledge Distillation
Knowledge distillation(KD) is a common approach to improve model performance
in automatic speech recognition (ASR), where a student model is trained to
imitate the output behaviour of a teacher model. However, traditional KD
methods suffer from teacher label storage issue, especially when the training
corpora are large. Although on-the-fly teacher label generation tackles this
issue, the training speed is significantly slower as the teacher model has to
be evaluated every batch. In this paper, we reformulate the generation of
teacher label as a codec problem. We propose a novel Multi-codebook Vector
Quantization (MVQ) approach that compresses teacher embeddings to codebook
indexes (CI). Based on this, a KD training framework (MVQ-KD) is proposed where
a student model predicts the CI generated from the embeddings of a
self-supervised pre-trained teacher model. Experiments on the LibriSpeech
clean-100 hour show that MVQ-KD framework achieves comparable performance as
traditional KD methods (l1, l2), while requiring 256 times less storage. When
the full LibriSpeech dataset is used, MVQ-KD framework results in 13.8% and
8.2% relative word error rate reductions (WERRs) for non -streaming transducer
on test-clean and test-other and 4.0% and 4.9% for streaming transducer. The
implementation of this work is already released as a part of the open-source
project icefall.Comment: Submitted to ICASSP 202
The methods to detect vacuum polarization by evanescent modes
We propose the evanescent-mode-sensing methods to probe the electrodynamics
(QED) vacuum polarization. From our methods, high-sensitivity can be achieved
even though the external field is much smaller than the Schwinger critical
field and may be realizable in contemporary experimental conditions. The
methods are based on the effect of phase change and time delay of evanescent
wave which is transmitted in QED vacuum. These methods can also be widely used
in sensitive probing of tiny dissipation in other fields
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