A5000446800- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Synthetic Organic Chemistry Methods
- Integrated Circuits and Semiconductor Failure Analysis
- Traditional and Medicinal Uses of Annonaceae
- Force Microscopy Techniques and Applications
- Plant-derived Lignans Synthesis and Bioactivity
- Near-Field Optical Microscopy
- Semiconductor materials and devices
- 3D IC and TSV technologies
- Electronic Packaging and Soldering Technologies
- Copper Interconnects and Reliability
- Remote Sensing and Land Use
- Chemical synthesis and alkaloids
- Alkaloids: synthesis and pharmacology
- Catalytic C–H Functionalization Methods
- Remote Sensing in Agriculture
- Crystallography and molecular interactions
- 2D Materials and Applications
- Adhesion, Friction, and Surface Interactions
- Molecular Junctions and Nanostructures
- Oxidative Organic Chemistry Reactions
- Advanced Electron Microscopy Techniques and Applications
- Microwave and Dielectric Measurement Techniques
- Electrostatic Discharge in Electronics
The University of Texas Southwestern Medical Center
2016-2023
Southwestern Medical Center
2016-2023
National Institute of Standards
2013-2022
National Institute of Standards and Technology
2013-2022
Micron (United States)
2022
Peking University
2009-2020
Physical Measurement Laboratory
2014-2019
Theiss Research
2018
State Key Laboratory of Remote Sensing Science
2017
Beijing National Laboratory for Molecular Sciences
2010-2016
All together: A concise strategy for the first diastereoselective total synthesis of (±)-schindilactone is reported. The features a ring-closing metathesis, thiourea/cobalt-catalyzed Pauson–Khand reaction, and thiourea/palladium-catalyzed carbonylative annulation reaction. chemistry can be applied to structures related schindilactone A. Detailed facts importance specialist readers are published as "Supporting Information". Such documents peer-reviewed, but not copy-edited or typeset. They...
Abstract Chiral N‐heterocyclic carbenes were found to be efficient catalysts for the formal [4+2] cycloaddition reaction of alky(aryl)ketenes and o ‐quinone methides give corresponding 3,3,4‐trisubstituted 3,4‐dihydrocoumarins in good yields with diastereoselectivities excellent enantioselectivities.
A concise total synthesis of (+)-propindilactone G, a nortriterpenoid isolated from the stems Schisandra propinqua var. propinqua, has been achieved for first time. The key steps include an asymmetric Diels-Alder reaction, Pauson-Khand Pd-catalyzed reductive hydrogenolysis and oxidative heterocoupling reaction. These reactions enabled G in only 20 steps. As consequence our synthetic studies, structure revised.
In this work, we compare the electrical characteristics of MoS2 field-effect transistors (FETs) with Ag source/drain contacts those Ti and demonstrate that metal–MoS2 interface is crucial to device performance. FETs show more than 60 times higher ON-state current contacts. order better understand mechanism performance contacts, 5 nm Au/5 (contact layer) or film was deposited onto monolayers few layers, topography metal films characterized using scanning electron microscopy atomic force...
Eine kurze Route führt zur diastereoselektiven Totalsynthese von (±)-Schindilacton A. Schlüsselschritte sind eine Ringschlussmetathese, Thioharnstoff/Cobalt-katalysierte Pauson-Khand-Reaktion und Thioharnstoff/Palladium-katalysierte carbonylierende Anellierung. Derivate Schindilacton A ebenfalls zugänglich.
Abstract The final phase for the total synthesis of (±)‐schindilactone A ( 1 ) is described herein. Two independent synthetic approaches were developed that featured Pd–thiourea‐catalyzed cascade carbonylative annulation reactions to construct intermediate 3 and a RCM reaction make 4 . Other important steps enabled completion included: 1) Ag‐mediated ring‐expansion form vinyl bromide 17 from dibromocyclopropane 30 ; 2) Pd‐catalyzed coupling with copper enolate synthesize ketoester 16 3)...
Abstract The successful synthesis of the highly complex model compound ( 2 ) CEFGH ring system schindilactone A 1 is described. Several synthetic methodologies were developed and applied to achieve this goal, including ring‐closing metathesis (RCM) Co–thiourea‐catalyzed Pauson–Khand reactions. Furthermore, two independent approaches for construction GH , key steps which included Pd–thiourea‐catalyzed carbonylative annulation, methylation, sequential RCM/oxa‐Michael‐addition chemistry herein...
We demonstrate the ability of scanning microwave microscope (SMM) to detect subsurface metal lines embedded in a dielectric film with sub-micrometer resolution. The SMM was used image 1.2 μm-wide Al–Si–Cu encapsulated either 800 nm or 2300 plasma deposited silicon dioxide. Both reflected (S11) amplitude and phase shifted near resonance frequency while tip scanned across these buried lines. shallower line edge could be resolved within 900 ± 70 nm, deeper 1200 260 nm. spatial resolution...
The enantioselective synthesis of the fully functionalized BCDE tetracyclic ring system propindilactone G (A) is reported. Several synthetic methods were developed and applied to achieve this goal, including: 1) an asymmetric Diels-Alder reaction in presence Hayashi's catalyst for optically pure key intermediate 3; 2) intramolecular Pauson-Khand (PKR) stereoselective with all-carbon chiral quaternary center at C13 position by using TMS-substituted acetylene as substrate; 3) Pd-catalyzed...
Abstract Our first‐generation synthetic study towards the total synthesis of propindilactone G ( 1 ) and its analogues is reported. The key steps were an intramolecular Pauson–Khand reaction (PKR) a vinylogous Mukaiyama (VMAR). stereoselective CDE ring moiety with all‐carbon quaternary center through PKR was difficult, whilst VMAR afforded product opposite stereochemistry at C20 position on side chain. These results led us to redesign our strategy for compound .
Two independent synthetic approaches were evaluated for the final phase of asymmetric total synthesis propindilactone G (1). The key steps that led to completion included: 1) an intermolecular oxidative heterocoupling reaction enolsilanes link core structure side chain; 2) Wittig formation α,β,γ,δ-unsaturated ester; and 3) a regio- stereoselective OsO4 -catalyzed dihydroxylation enone, followed by intramolecular lactonization afford product. These reactions enabled (+)-propindilactone in...
Surface dipoles are a powerful tool in interfacial modification for improving device output via energy level matching. Fluorinated alkanethiols show strong promise these applications as they can generate large and tunable based on fluorine location chain length. Furthermore, chains be designed to possess fluorocarbons solely along the backbone, enabling an "embedded" configuration that generates significant dipole effect from fluorines while maintaining surface chemistry prevent deleterious...
Scanning probe microscopes (SPMs) have some ability to image sub-surface structures. This paper describes the theoretical and practical basis for imaging metal lines buried beneath insulating layers regions or voids within with SPMs. Three techniques are discussed: scanning Kelvin force microscopy (SKFM) potential of lines, microwave (SMM) capacitance SMM in metals through frequency dependence skin depth. A test chip, designed at NIST, that contains structures precisely produce electric...
Ceramide is a lipid molecule that regulates diverse physiological and pathological reactions in part through inverting the topology of certain transmembrane proteins. This topological inversion achieved regulated alternative translocation (RAT), which reverses direction by membrane proteins are translocated across endoplasmic reticulum during translation. However, owing to technical challenges studying protein-ceramide interaction, it remains unclear how ceramide levels sensed cells trigger...
Palladium(II) acetate, in combination with triphenylphosphine, catalyzes direct arylation of 1,4-disubstituted 1,2,3-triazoles effectively. This C-H reaction provides facile access to fully substituted triazoles well-defined regiochemistry.
In recent decades, various kinds of remote sensing-based drought indexes have been proposed and widely used in the field monitoring. However, drought-related software platform development lag behind theoretical research. The current monitoring systems focus mainly on information management publishing, cannot implement professional or parameter inversion modelling, especially models based multi-dimensional feature space. view above problems, this paper aims at fixing gap with a...
SnTe is a conventional thermoelectric material and has been newly found to be topological crystalline insulator. In this work, back-gate field-effect transistors have fabricated fully characterized. The devices exhibit n-type transistor behaviors with excellent current-voltage characteristics large on/off ratio (>106). device threshold voltage, conductance, mobility, subthreshold swing studied compared at different temperatures. It that the swings as function of temperature an...
cGAMP is a signaling molecule produced by the cGAS-DNA complex to establish antimicrobial and antitumor immunity through STING. Whereas STING activation holds potential as new strategy treat cancer, generally considered unsuitable for in vivo use because of rapid cleavage its phosphodiester linkages limited cellular uptake under physiological conditions. Consequently, phosphorothioation fluorination are commonly used improve metabolic stability permeability synthetic analogues. We now show...
In this paper, we discuss the use of broadband high frequency electromagnetic waves (RF) to non-destructively identify, classify and characterize performance-limiting defects in emerging nanoelectronic devices. As an illustration, impact thermal cycling on RF signal characteristics (insertion loss (S21) return (S11)) is used infer thermo-mechanical stress-induced metal interconnects. The inferred are supported with physical analytical data where possible.
Drought is a harmful and headachy natural disaster in the world, which has caused considerable loss to agricultural production economy per year with high frequency. It therefore very important necessary for drought monitoring over large scales by remotely sensed techniques. In order establish physically meaningful water stress index, SWIR bands strong absorption features are used this study, then shortwave infrared indices (SIWSI) constructed using NIR bands. A representative arid semi-arid...