Publications by authors named "Keke Chang"

Functional coatings, including organic and inorganic coatings, play a vital role in various industries by providing a protective layer and introducing unique functionalities. However, its design often involves time-consuming experimentation with multiple materials and processing parameters. To overcome these limitations, data-driven approaches are gaining traction in materials science.

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The development of fast neutron reactors with improved efficiency and sustainability, being a tangible solution to the large-scale utilization of nuclear energy, serves as a critical step prior to the commercialization of fusion energy. These reactors use liquid metal coolants, which can weaken the durability of metallic components. Conventional design of protective coatings counts upon thermodynamics, which often overlooks the kinetic factors such as structural evolutions, resulting in deteriorated coating properties.

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Platinum-based catalysts are widely used in hydrogen evolution reactions; however, their applications are restricted because of the cost-efficiency trade-off. Here, we present a thermodynamics-based design strategy for synthesizing an AlMnRu (atomic %) metal catalyst via combinatorial magnetron co-sputtering. The new electrocatalyst is composed of ~2 nanometers of medium-entropy nanocrystals surrounded by ~2 nanometers of amorphous regions.

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Article Synopsis
  • The study focuses on assessing heavy metal pollution in the soil surrounding the Luqionggang landfill in Shannan City, Tibet, using methods like the geo-accumulation index and potential ecological risk index.
  • Results show that the soil has a strong alkaline average pH of 9.37, with mercury (Hg) and nickel (Ni) exceeding background levels, while other heavy metals remain within safety standards.
  • The findings indicate that heavy metal pollution is most significant in the western area of the landfill, with Hg posing the highest ecological risk, categorizing the overall pollution level as moderate.
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Strength and toughness are at odds with each other in coating design. Constructing strength-toughness-integrated coatings has long been a pursuit in materials design but is a challenge to achieve. Conventional wisdom suggests that growth of coatings is only a uniform cumulative growth on a two-dimensional plane.

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The Tibetan Plateau works as an important environmental and ecological barrier for the Asian continent. The researches on Tibetan environment and ecology are becoming extensive, but there is no systematic summary of research hotspots and trends in this field. Here, we analyzed 9180 publications retrieved from the WOS and CNKI during 2000 ~ 2020.

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Phase transformations occurring in a solid govern the structural and physical properties significantly. Nevertheless, deformation-induced phase transition in a soft-brittle solid has not been demonstrated yet. Soft-brittle cadmium zinc telluride (CZT) based instruments have produced technological breakthroughs in the semiconductor industry, and therefore their phase transformations have been widely investigated during the past 60 years.

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Friction and wear remain the primary modes for energy dissipation in moving mechanical components. Superlubricity is highly desirable for energy saving and environmental benefits. Macroscale superlubricity was previously performed under special environments or on curved nanoscale surfaces.

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Tailoring of individual single-atom-thick layers in nanolaminated materials offers atomic-level control over material properties. Nonetheless, multielement alloying in individual atomic layers in nanolaminates is largely unexplored. Here, we report 15 inherently nanolaminated V( Sn)C ( = Fe, Co, Ni, Mn, and combinations thereof, with x ∼ 1/3) MAX phases synthesized by an alloy-guided reaction.

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No in situ nanomechanical tests on damaged brittle materials have been demonstrated. This means that the transition route in damaged silicon (Si) under deformation is elusive. A gap is formed between abrasive machining and present nanomechanical tests, due to the unmatched nanostructure produced.

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Previous studies predict pressure-induced superlubricity, but that is still undetermined due to the absence of a probing technique. Here, we present unprecedented mutual identification between the superlubricity and atomic-scale image from atomic force microscopy (AFM) measurement by the first-principles simulation of metallic Cu tip scanning on carbon nanostructures. With decreasing tip height, the sliding potential evolves from anticorrugated, to substantially flattened, and eventually to corrugated patterns, inducing superlubricity of the flattened potential at the critical height.

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Nanolaminated materials are important because of their exceptional properties and wide range of applications. Here, we demonstrate a general approach to synthesizing a series of Zn-based MAX phases and Cl-terminated MXenes originating from the replacement reaction between the MAX phase and the late transition-metal halides. The approach is a top-down route that enables the late transitional element atom (Zn in the present case) to occupy the A site in the pre-existing MAX phase structure.

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Although aptamer-functionalized AuNPs technology exhibits great potential in analytical and biological chemistry, direct analysis of molecules at a low concentration using colorimetric assay remains challenging. The development of intuitive methods has attracted interest for promising detection of melamine in milk samples due to a demand for stable and understandable process. In this study, we propose a rapid and facile colorimetric measurement method of melamine combined aptamer-functionalized AuNPs in contaminated milk samples.

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Article Synopsis
  • The study investigates how chemical composition affects phase formation and mechanical properties in Pt-Ir and Pt-Au thin films, revealing that a single metastable Pt-Ir solid solution forms across all conditions, while Pt-Au tends to decompose into two phases at higher temperatures.
  • In the Pt-Ir films, changes in lattice parameters and Young's modulus align with the rule of mixtures and ab initio data, while in the Pt-Au films, lattice parameters remain constant despite changes in composition in the dual phase region.
  • The differences in phase formation are explained using CALPHAD results and estimated activation energy for surface diffusion, noting that Ir in Pt-Ir faces a much higher energy barrier than
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Nanostructures in silicon (Si) induced by phase transformations have been investigated during the past 50 years. Performances of nanostructures are improved compared to that of bulk counterparts. Nevertheless, the confinement and loading conditions are insufficient to machine and fabricate high-performance devices.

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Paper aging and degradation are growing concerns for those who are responsible for the conservation of documents, archives, and libraries. In this study, the paper aging was investigated using laser-induced fluorescence spectroscopy (LIFS), where the fluorescence properties of 47 paper samples with different ages were explored. The paper exhibits fluorescence in the blue-green spectral region with two peaks at about 448 nm and 480 nm under the excitation of 405 nm laser.

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Oxidation of BiTe (space group R [Formula: see text] m) has been investigated using experimental and theoretical means. Based on calorimetry, x-ray photoelectron spectroscopy and thermodynamic modelling, BiTe is at equilibrium with BiO and TeO, whereby the most stable compound is BiTe, followed by BiO. The reactivity of Bi towards oxygen is expected to be higher than that of Te.

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Abscisic acid (ABA) plays an important role in abiotic stress response and physiological signal transduction resisting to the adverse environment. Therefore, it is very essential for the quantitative detection of abscisic acid (ABA) due to its indispensable role in plant physiological activities. Herein, a new detection method based on localized surface plasmon resonance (LSPR) using aptamer-functionalized gold nanoparticles (AuNPs) is developed without using expensive instrument and antibody.

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A biosensing system with optical fibers is proposed for the colorimetric detection of melamine in liquid milk samples by using the localized surface plasmon resonance (LSPR) of unmodified gold nanoparticles (AuNPs). The biosensing system consists of a broadband light source that covers the spectral range from 200 nm to 1700 nm, an optical attenuator, three types of 600 μm premium optical fibers with SMA905 connectors and a miniature spectrometer with a linear charge coupled device (CCD) array. The biosensing system with optical fibers is low-cost, simple and is well-proven for the detection of melamine.

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A method to model the metastable phase formation in the Cu-W system based on the critical surface diffusion distance has been developed. The driver for the formation of a second phase is the critical diffusion distance which is dependent on the solubility of W in Cu and on the solubility of Cu in W. Based on comparative theoretical and experimental data, we can describe the relationship between the solubilities and the critical diffusion distances in order to model the metastable phase formation.

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The purpose of this study was to develop a portable surface plasmon resonance (SPR) bioanalyzer for the sensitive detection of O157:H7 in comparison with an enzyme-linked immunosorbent assay (ELISA). The experimental setup mainly consisted of an integrated biosensor and a homemade microfluidic cell with a three-way solenoid valve. In order to detect O157:H7 using the SPR immunoassay, 3-mercaptopropionic acid (3-MPA) was chemisorbed onto a gold surface via covalent bond for the immobilization of biological species.

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Article Synopsis
  • Ethylene gas can be effectively measured as an indicator of fruit ripening using a sensitive electrochemical sensor, which operates based on a bias potential applied to the electrodes.
  • A calibration curve was created using standard ethylene gas concentrations, showing a strong linear relationship (R² = 0.9976) between sensor responses and ethylene concentrations ranging from 0 to 10 ppm.
  • The developed measurement system is compact, cost-effective, and able to quickly detect trace ethylene levels in fruits like apples, pears, and kiwis with a detection limit of 0.413 ppm.
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The aim of this study was to develop a circuit for an inexpensive portable biosensing system based on surface plasmon resonance spectroscopy. This portable biosensing system designed for field use is characterized by a special structure which consists of a microfluidic cell incorporating a right angle prism functionalized with a biomolecular identification membrane, a laser line generator and a data acquisition circuit board. The data structure, data memory capacity and a line charge-coupled device (CCD) array with a driving circuit for collecting the photoelectric signals are intensively focused on and the high performance analog-to-digital (A/D) converter is comprehensively evaluated.

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Article Synopsis
  • Kinetic analysis helps quantify how biomolecules, like antibodies and antigens, bind or dissociate over time, which is crucial for understanding biological processes.
  • Surface plasmon resonance biosensors are used to study these interactions, assessing binding affinity and how these processes contribute to immune responses and cell signaling.
  • The paper introduces a new analysis method using the Marquardt algorithm for better curve-fitting of these interactions, improving accuracy and efficiency compared to traditional methods.
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The application of titanium (Ti) based biomedical materials which are widely used at present, such as commercially pure titanium (CP-Ti) and Ti-6Al-4V, are limited by the mismatch of Young's modulus between the implant and the bones, the high costs of products, and the difficulty of producing complex shapes of materials by conventional methods. Niobium (Nb) is a non-toxic element with strong β stabilizing effect in Ti alloys, which makes Ti-Nb based alloys attractive for implant application. Metal injection molding (MIM) is a cost-efficient near-net shape process.

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