A Closer Look at Parameter-Efficient Tuning in Diffusion Models

Large-scale diffusion models like Stable Diffusion are powerful and find various real-world applications while customizing such models by fine-tuning is both memory and time inefficient. Motivated by the recent progress in natural language processing, we investigate parameter-efficient tuning in large diffusion models by inserting small learnable modules (termed adapters). In particular, we decompose the design space of adapters into orthogonal factors -- the input position, the output position as well as the function form, and perform Analysis of Variance (ANOVA), a classical statistical approach for analyzing the correlation between discrete (design options) and continuous variables (evaluation metrics). Our analysis suggests that the input position of adapters is the critical factor influencing the performance of downstream tasks. Then, we carefully study the choice of the input position, and we find that putting the input position after the cross-attention block can lead to the best performance, validated by additional visualization analyses. Finally, we provide a recipe for parameter-efficient tuning in diffusion models, which is comparable if not superior to the fully fine-tuned baseline (e.g., DreamBooth) with only 0.75 \% extra parameters, across various customized tasks.Comment: 8page

Realization of multiple charge density waves in NbTe2 at the monolayer limit

Abstract: Layered transition-metal dichalcogenides (TMDCs) down to the monolayer (ML) limit provide a fertile platform for exploring charge-density waves (CDWs). Though bulk NbTe2 is known to harbor a single axis 3*1 CDW coexisting with non-trivial quantum properties, the scenario in the ML limit is still experimentally unknown. In this study, we unveil the richness of the CDW phases in ML NbTe2, where not only the theoretically predicted 4*4 and 4*1 phases, but also two unexpected sqrt(28)*sqrt(28) and sqrt(19)*sqrt(19) phases, can be realized. For such a complex CDW system, we establish an exhaustive growth phase diagram via systematic efforts in the material synthesis and scanning tunneling microscope characterization. Moreover, we report that the energetically stable phase is the larger scale order (sqrt(19)*sqrt(19)), which is surprisingly in contradiction to the prior prediction (4*4). These findings are confirmed using two different kinetic pathways, i.e., direct growth at proper growth temperatures (T), and low-T growth followed by high-T annealing. Our results provide a comprehensive diagram of the "zoo" of CDW orders in ML 1T-NbTe2 for the first time and offer a new material platform for studying novel quantum phases in the 2D limit

SARS-CoV-2 infection causes dopaminergic neuron senescence

COVID-19 patients commonly present with signs of central nervous system and/or peripheral nervous system dysfunction. Here, we show that midbrain dopamine (DA) neurons derived from human pluripotent stem cells (hPSCs) are selectively susceptible and permissive to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. SARS-CoV-2 infection of DA neurons triggers an inflammatory and cellular senescence response. High-throughput screening in hPSC-derived DA neurons identified several FDA-approved drugs that can rescue the cellular senescence phenotype by preventing SARS-CoV-2 infection. We also identified the inflammatory and cellular senescence signature and low levels of SARS-CoV-2 transcripts in human substantia nigra tissue of COVID-19 patients. Furthermore, we observed reduced numbers of neuromelanin+ and tyrosine-hydroxylase (TH)+ DA neurons and fibers in a cohort of severe COVID-19 patients. Our findings demonstrate that hPSC-derived DA neurons are susceptible to SARS-CoV-2, identify candidate neuroprotective drugs for COVID-19 patients, and suggest the need for careful, long-term monitoring of neurological problems in COVID-19 patients.</p

SARS-CoV-2 infection causes dopaminergic neuron senescence

COVID-19 patients commonly present with signs of central nervous system and/or peripheral nervous system dysfunction. Here, we show that midbrain dopamine (DA) neurons derived from human pluripotent stem cells (hPSCs) are selectively susceptible and permissive to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. SARS-CoV-2 infection of DA neurons triggers an inflammatory and cellular senescence response. High-throughput screening in hPSC-derived DA neurons identified several FDA-approved drugs that can rescue the cellular senescence phenotype by preventing SARS-CoV-2 infection. We also identified the inflammatory and cellular senescence signature and low levels of SARS-CoV-2 transcripts in human substantia nigra tissue of COVID-19 patients. Furthermore, we observed reduced numbers of neuromelanin+ and tyrosine-hydroxylase (TH)+ DA neurons and fibers in a cohort of severe COVID-19 patients. Our findings demonstrate that hPSC-derived DA neurons are susceptible to SARS-CoV-2, identify candidate neuroprotective drugs for COVID-19 patients, and suggest the need for careful, long-term monitoring of neurological problems in COVID-19 patients.</p

The mixed-mode reliability stress of Silicon-Germanium heterojunction bipolar transistors

The objective of the dissertation is to combine the recent Mixed-Mode reliability stress studies into a single text. The thesis starts with a review of silicon-germanium heterojunction bipolar transistor fundamentals, development trends, and the conventional reliability stress paths used in industry, after which the new stress path, Mixed-Mode stress, is introduced. Chapter 2 is devoted to an in-depth discussion of damage mechanisms that includes the impact ionization effct and the selfheating effect. Chapter 3 goes onto the impact ionization effect using two-dimensional calibrated MEDICI simulations. Chapter 4 assesses the reliability of SiGe HBTs in extreme temperature environments by way of comprehensive experiments and MEDICI simulations. A comparison of the device lifetimes for reverse-EB stress and mixed-mode stress indicates different damage mechanisms govern these phenomena. The thesis concludes with a summary of the project and suggestions for future research in chapter 5.Ph.D.Committee Chair: Cressler, John; Committee Member: First, Phillip; Committee Member: Laskar, Joy; Committee Member: Shen, Shyh-Chiang; Committee Member: Tentzeris, Emmanoui

阿里巴巴：十年金融路

2012年9月，全世界最大的电子商务平台——阿里巴巴集团创始人马云在阿里网商大会上，将阿里未来定位为“平台、金融和数据”三大核心业务。自此，阿里在金融领域的动作频出，布局新业务、推出新产品和调整组织架构等齐头并进。阿里巴巴涉足金融之路并非一片坦途。随着大数据、云计算、平台,以及移动互联网等新兴技术的发展，B2B2C与O2O等商业模式的变革，马云在率先扛起互联网金融大旗时，不仅遭遇传统金融“大佬”的狙击，同时还得防范互联网“新贵”们的挑战。本案例以2002年阿里巴巴推出“诚信通”为开端，重点梳理阿里金融走过的十年历程、完成的关键七步，从过去、现在和未来三个维度全景展示阿里金融的发展历程、技术创新和商业变革，及挑战与思考

High-entropy oxide, (FeCoNiMnV)xO, boost the oxygen evolution

The sluggish kinetics of the oxygen evolution reaction (OER), an essential half-reaction of water splitting, lead to high OER overpotential and low energy-conversion efficiency, hampering its industrial application. Therefore, considerable attention has been paid to the development of efficient catalysts to accelerate the OER. In this study, we synthesized the high-entropy oxides [(FeCoNiMnV)xO] and used them as efficient OER catalysts. A simple oil-phase method was used to synthesize (FeCoNiMnV)xO. The catalytic performances of the (FeCoNiMnV)xO catalysts were modified by tuning the reaction temperature. The optimized (FeCoNiMnV)xO catalyst exhibited multiple elemental interactions and abundant exposed active sites, leading to an overpotential of approximately 264 mV to reach a current density of 10 mA cm−2 in 1 M KOH and stability of 50 h at 1000 mA cm−2. Thus, a highly active OER catalyst was synthesized. This study provides an efficient approach for the synthesis of high-entropy oxides

Behavior of superconductivity in a Pb/Ag heterostructure

The superconducting proximity effect is a long-standing topic of great importance in condensed matter physics. A crucial but unresolved issue is which interfacial and material details determine the efficiency of the proximity effect. In this work, we study an epitaxially grown superconductor (SC)/normal metal (NM) heterostructure (Pb/Ag) and find a spatially constant superconducting gap determined by local tunneling spectroscopy and magneto response measurements, despite the highly mismatched Fermi surfaces between individual Pb and Ag epitaxial layers, and the large differences in the lattice constants and electronic density of states in the separate components. The uniform superconducting gap is in contrast to the spatially varying pair potential with a discontinuity at the interface theoretically predicted for an ideal SC-NM junction and experimentally observed previously in several lateral SC-NM junctions. We experimentally verify that the transmission of electrons across the interface in the vertical Pb/Ag heterostructure is high enough that a new band structure emerges even at the single particle level. Our experimental results call for further theoretical work in order to develop predictive power for the proximity effect starting from realistic, material relevant microscopic models.This work was supported by ONR-N00014-14-1-0330, the National Science Foundation DMR- 1506678, DMR-1507621, NSF Materials Research Science and Engineering Center Grant No. DMR-1720595, DMR-1729588, and the Welch Foundation (F-1672). H. -J. Gao acknowledges support by MOST grant No. 2013CBA01601 and by NSFC grant No. 61390501. G.A.F. acknowledges support from a Simons Fellowship and a QuantEmX grant from ICAM and the Gordon and Betty Moore Foundation.Center for Dynamics and Control of Material

SiGe BiCMOS Precision Voltage References for Extreme Temperature Range Electronics

Abstract — We present the first investigation of the optimal implementation of SiGe BiCMOS precision voltage references for extreme temperature range applications (+120 oC to-180 oC and below). We have developed and fabricated two unique Ge profiles optimized specifically for cryogenic operation, and for the first time compare the impact of Ge profile shape on precision voltage reference performance down to-180 oC. Our best case reference achieves a 28.1 ppm / oC temperature coefficient over +27 oC to-180 oC, more than adequate for the intended lunar electronics applications. Index Terms — analog circuits, SiGe HBT, cryogenic temperature, voltage reference, device physics