Bond Force Research Articles

Activating continuous dislocation pinning enhanced toughness of nanocomposite coating through specially oriented semicoherent heterointerface lattice distortion

Ionic crystal ceramics are known to be susceptible to brittle cracks along the intergranular due to the strong ionic bond forces. Accordingly, an outstanding toughened coating consisting of yttria-stabilized tetragonal zirconia (YSTZ) and MgO, with a reinforced heterointerface, has been successfully achieved through the plasma electrolytic oxidation process. The results demonstrate that the enhanced Zr/Y–O bond strength improves the interfacial strength of the ionic crystal, while the lattice distortion activates continuous dislocation pinning at the (101) YSTZ//(111) MgO semicoherent heterointerface effectively hinders crack propagation of the coating. With the YSTZ content approaching 65 %, the toughness (KIC) value surpasses that of PEO coating by 42 %. These findings not only elucidate the scientific foundation for the improved toughness of the YSTZ/MgO nanocoating but also provide valuable insights into design strategies for improving ceramic toughness.

Heat transfer, crystallization and properties of Bayan Obo tailings-based nanocrystalline glass-ceramics processed with microwave radiation

Using Bayan Obo tailings containing rare earth element as raw material to prepare nanocrystalline glass-ceramics by microwave heating is a feasible scheme for the sustainable development of resources and low-carbon production. In this paper, the effects of conduction, infrared, microwave and plasma heating on nucleation were studied in order to obtain evidence for a thermal and non-thermal microwave effect. The differences in the mechanical properties, high-temperature softening properties and microstructures of the glass-ceramics prepared by conventional and microwave heating were analyzed. The results showed that microwave heating had a higher heating rate than conventional heating. The volumetric heating reduced the dependence of heat conduction within the sample, forming a uniform thermodynamic system for nucleation. The polymeric character of the silicon-oxygen network could be reduced by microwave radiation to promote nucleation, and fine nanocrystals with globular crystals and a uniform microstructure were produced after continuous nucleation-crystallization. In contrast to conventional heat treatment, the flexural strength of the samples increased from 169 MPa to 219.9 MPa under microwave radiation, and the thermal stability improved. The excellent mechanical properties were attributed to the increased Si–O stretching vibration frequency and bond force. In addition, the structure of the diopside cell tended to be dumpy with a decreased β angle, and the crystal orientation was affected. Tailings-based nanocrystalline glass-ceramics with excellent properties can be prepared in a short processing time by microwave heating.

Influence of cobalt on the performance of Pt/CeO2 for CO-PROX at low temperature: reducing the energy of the Pt–O–Ce bond

The interaction of Pt–Co–Ce decreases the bond energy of Pt–O–Ce, thereby promoting the redox cycle via the MvK mechanism. It is helpful in reducing the reaction temperature, widening the temperature window and improving the selectivity of CO2.

The 3d-4f electron transition of the CoS2/CeO2 heterojunction for efficient oxygen evolution.

CoS2/CeO2, exhibiting the 3d-4f orbital coupling effect, is developed and shows exceptional OER activity, with an overpotential of 140 mV at 10 mA cm-2. DFT calculation and Raman spectra show the existence of a d-p-f electron transport ladder that can accelerate electron transfer through the Co-O(S)-Ce bond, optimize the adsorption free energy, and enhance the catalytic activity.

Theoretical analysis of cargo transport by catch bonded motors in optical trapping assays.

Dynein motors exhibit catch bonding, where the unbinding rate of the motors from microtubule filaments decreases with increasing opposing load. The implications of this catch bond on the transport properties of dynein-driven cargo are yet to be fully understood. In this context, optical trapping assays constitute an important means of accurately measuring the forces generated by molecular motor proteins. We investigate, using theory and stochastic simulations, the transport properties of cargo transported by catch bonded dynein molecular motors - both singly and in teams - in a harmonic potential, which mimics the variable force experienced by cargo in an optical trap. We estimate the biologically relevant measures of first passage time - the time during which the cargo remains bound to the microtubule and detachment force - the force at which the cargo unbinds from the microtubule, using both two-dimensional and one-dimensional force balance frameworks. Our results suggest that even for cargo transported by a single motor, catch bonding may play a role depending on the force scale which marks the onset of the catch bond. By comparing with experimental measurements on single dynein-driven transport, we estimate realistic bounds of this catch bond force scale. Generically, catch bonding results in increased persistent motion, and can also generate non-monotonic behaviour of first passage times. For cargo transported by multiple motors, emergent collective effects due to catch bonding can result in non-trivial re-entrant phenomena wherein average first passage times and detachment forces exhibit non-monotonic behaviour as a function of the stall force and the motor velocity.

The fully coupled thermo-mechanical dual-horizon peridynamic correspondence damage model for homogeneous and heterogeneous materials

To accurately address the thermally induced dynamic and steady-state crack propagation problems for homogeneous and heterogeneous materials involving crack branching, interfacial de-bonding and crack kinking, we propose the fully coupled thermo-mechanical dual-horizon peridynamic correspondence damage model (TM-DHPD). To this end, the integral coupled equations for TM-DHPD are firstly derived within the framework of thermodynamics. And then, the alternative dual-horizon peridynamic correspondence principle is used to derive the constitutive bond force state, heat flow state and their general linearizations. Moreover, the unified criterion for bond damage is proposed to characterize the internal bond damage in a single material and the interface bond damage in dissimilar materials. To ensure convergence and accuracy, the coupled equations are solved using the standard implicit method without the use of artificial damping. In both homogeneous and heterogeneous materials, some representative and challenging numerical cases are examined, such as dynamic crack branching in a centrally heated disk and multiple interface failure of thermal barrier coating. The numerical results are in good agreement with the available experimental results or the previous predictions, which shows the great potential of the proposed TM-DHPD in addressing the physics of numerous thermally induced fractures in the real-world engineering problems.

Rational Design of l-Threonine Transaldolase-Mediated System for Enhanced Florfenicol Intermediate Production.

l-threo-p-methylsulfonylphenylserine (compound 1b) is the main intermediate of florfenicol, and its efficient synthesis has been the subject of current research. Herein, Burkholderia diffusa l-threonine transaldolase (BuLTTA) was rationally designed based on the sequence-structure-function relationship. A mutant M4 (Asn35Ser/Thr352Asn) could produce 35.5 mM 1b with 88.8% conversion and 93.8% diastereoselectivity, 314 and 129% of the values observed for wild-type BuLTTA. Molecular dynamics simulations indicated that the shortened distance between key active site residues and the transition state (PLP-1b) and the improved hydrogen bond force enhanced the catalytic performance of the M4 variant. Then, the mutant M4 was combined with K. kurtzmanii alcohol dehydrogenase (KkADH) to eliminate the BuLTTA-inhibiting byproduct acetaldehyde, and a cosubstrate was added to regenerate the ADH cofactor NADH. Under optimized conditions, the yield of 1b reached 115.2 mM with a conversion of 96% and a diastereoselectivity of 95.5%. This work provides a new strategy for the efficient and sustainable production of 1b.

Synergistic mechanism of hetero-interfacial oxygen vacancies on catalytic oxidation of 1,2-dichloroethane over Ru-modified monolayer-dispersed WOx/CeO2 catalysts: Differences in distribution of active sites

Ru-modified monolayer-dispersed WOx/CeO2 hybrid composites were prepared by co-impregnation (CI) and step impregnation (SI) methods, and the effects of active site distribution on the catalytic oxidation of 1,2-dichloroethane (DCE) were investigated. Ru species tends to be deposited on the monolayer-dispersed WOx (m-WOx) by SI method, which can increase the oxygen vacancies (OV,m-WOx) at m-WOx/CeO2 interfaces. Abundant OV,m-WOx can promote the formation of more active W–OH and accelerate the dechloridation and oxydehydrogenation of DCE. Oppositely, for CI method, Ru species exists mainly in the form of Ru−O−Ce bonds, increasing the oxygen vacancies (OV,RuCe) into CeO2 surface lattices and promoting the deep oxidation of intermediate products. The closer contact between the two hetero-interfacial oxygen vacancies (OV,RuCe and OV,m-WOx) on Ru-modified m-WOx/CeO2 produces a stronger synergistic effect on DCE activation and oxidation, and meanwhile advantageously inhibits the adsorption of chlorine species as well as the formation of polychlorinated by-products.

Preparing Multi-Functional Protein Textiles by the Flavonoid-Rich Ginkgo Biloba L. Leaf Extracts

ABSTRACT Flavonoids in ginkgo biloba L. leaf (abbreviated as GBL) extracts exhibited superior biological activity, but their light color limited their development in the field of textiles. Therefore, this work innovatively used GBL extracts as textile functional finishing agent, through exhaustion dyeing process endowed protein fabrics the multifunction. Flavonoids of GBL in protein fabrics showed outstanding rubbing and washing fastness, becuase of their formed strong affinity by electrostatic attraction, hydrogen bond and van der Waals force. Moreover, the flavonoid content on protein fibers was enhanced by the GBL extract concentration increase, treating time stretch, temperature improve. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy result that flavonoids in GBL extracts adsorbent the fibers. In addition, the treated protein fabrics possessed good antioxidant, antibacterial and heavy metal protective performance. Finally,GBL dyed silk fabrics exhibited stronger functionalities than GBL dyed wool fabrics. This work provides the methods that reuse GBL waste and functionalization of protein fabric.

(Invited) Al-Al Waferbonding Process Development for Heterogeneous Integration

3D heterogeneous integration provides the possibility to combine dissimilar semiconductor technologies and add new components to obtain a higher performance and increase the functionality. Aligned Wafer level bonding, where the chips are vertically interconnected is known as one of the key technologies needed for 3D integration. Here, Aluminum to aluminum bonding is very attractive due to its easy compatibility to complementary metal-oxide-semiconductor (CMOS) processes. Furthermore Al-Al bonding provides not only the mechanical attachment between different wafers but also enables a good electrical and thermal conductivity. One of the main challenges for Al-Al thermocompression bonding is the formation of aluminum oxide which inhibits uniform and reliable Al-Al bonding at low temperatures with minimum bond forces. To overcome this limitation, this work presents a surface activated bonding process carried out in an EVG® ComBond® 200 mm automated high vacuum wafer bonding system. Here, the surface oxide is first removed with an argon plasma treatment. Without breaking vacuum to avoid a reoxidation, the wafers are optically aligned to each other and then bonded by applying force and temperature.This paper shows an integration concept for patterned 200 mm Al-Al bonded wafers and focusses on different factors influencing the quality of the Al-Al bonding. The bond quality is evaluated with various characterization methods. For electrical characterization single contacts with sizes down to 10 µm x 10 µm are analyzed. To characterize the bond interface C-mode scanning acoustic microscopy (C-SAM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) are used. To calculate the bond strength, shear force measurements are carried out. The alignment accuracy is evaluated with an infrared microscope measuring the overlay of specific alignment marks at different dice across the wafer.A great factor influencing the bonding quality are the process parameters during the actual bonding process. Here, we vary the duration of the argon plasma activation from 1.5 to 5 min. Additionally, the impact of the bonding temperature in the range of 200 to 300 °C and the influence of the bonding force between 20 and 60 kN is investigated. Furthermore the bonding time is varied from 15 to 60 min. The best results with contact resistances in the mΩ-Range and a bonding yield >95% are achieved for wafers bonded for 1 h at 300 °C with 60 kN and an activation time of 5 min.Besides the bonding parameters, also the wafer fabrication prior to the bonding process has a significant influence on the Al-Al bond quality. In this context, the local and global topography of the wafers play an important role. An improved wafer flatness increases the contact area during bonding and can thus contribute to a better bonding result. In order to reduce the surface roughness of the Al bonding pads, we vary the parameters for the aluminum deposition and analyze the impact of different adhesion/barrier layers below the aluminum bonding film. The paper shows that also the tungsten plugs under the Al bonding pads affect their topography and thus the bond quality. In addition, we modify an etch-mask influencing the condition of the Al bonding pads and directly correlate it to the bonding yield and electrical resistance. Moreover, the impact of the wafer bow on the bond strength is studied.Even the processes that follow the Al-Al bonding can still negatively affect the final result. After bonding a backside grinding process is used, which causes silicon dust on the wafer surface and requires an additional cleaning step. This study shows the effect of an ultrasonic clean on the measured bond strength.In summary we present a surface activated, low temperature Al-Al bonding process of patterned 200 mm wafers with a high bonding yield, low contact resistances and an alignment accuracy close to 1 µm. Our work presents an integration concept for Al-Al bonded wafers and highlights different factors that influence the bonding result.

Study of Physical and Electrical Properties of Sandwich Compound as Drug Delivery to Transport Chlorpheniramine Medication Using Density Functional Theory

Sandwich compounds have widespread applications in fields such as medicine, molecular electronics, and pharmacology. This study is an attempt to design drug delivery by using a di-benzene chromium sandwich compound Cr(η6-C6H6)2 to transport chlorpheniramine medication (C16H19ClN2). Some of the electronic and spectrum properties of the sandwich compounds and chlorpheniramine medication using density functional theory (DFT) and the B3LYP/6-31G (d,p) basis set were investigated. The sandwich compound, chlorpheniramine, and the sandwich compound bonded with chlorpheniramine were evaluated by studying the geometry optimization and calculating the HOMO and LUMO, bond length, energy gap, UV-VIS, IR spectrum, and force constant for the three compounds. These calculations highlight several features of the new compound, including strength and higher stability. In the investigation, it was observed that the UV-VIS and IR spectra for the new compound exhibits shifts towards longer wavelengths absorptions. The energy gap values for the three compounds were determined to be 2.1768 eV, 4.813 eV, and 3.0557 eV, respectively, while the force constant values were measured as 3 mDyne/Å, 2.7 mDyne/Å, and 4 mDyne/Å.

Pickering emulsion gel stabilized by Auricularia auricula protein

Pickering emulsion is a new stable emulsion system with high safety. In this study, Auricularia auriculata mycelium protein-xanthan gum composite pickering emulsion (AAMP/XG PE) 3D printing ink was prepared and characterized. The results of particle size, Zeta potential and FTIR showed that electrostatic force and hydrogen bond force promoted the formation of XG-AAMP complex. The morphology of the confocal laser scanning microscopy (CLSM) indicated that adding XG reduced the droplet size of AAMP/XG PE, promoting the formation of its tight structure. The rheological properties showed that AAMP/XG Pickering emulsion gel containing 2% XG had excellent water holding capacity, extrudability and supportability, which enhanced the stability and resolution of 3D printing AAMP/XG Pickering ink. Finally, AAMP/XG PE gel had good storage stability (30 days). In this study, we used AAMP/XG Pickering emulsion to create semi-solid structure to replace hydrogenated oil. It has provided a new way to increase the application diversity of AAMP/XG Pickering emulsion in food sectors.

Analysis of debonding mechanism and concrete cover failure of steel and steel fibre reinforced concrete composite beams

To solve the construction problems of steel reinforced concrete structures, the rebar cage was replaced by steel fibres, thus an innovative structure, steel and steel fibre reinforced concrete (SSFRC) structure, was proposed. Based on the four-point bending tests and numerical modelling of 18 SSFRC beams, the debonding mechanism and concrete cover failure were investigated. The results reflected that SSFRC beams experienced shearing failure, debonding failure and bending failure. Bonding cracks existed in most specimens, and the generation of abundant bonding cracks led to the sudden load decrease. The uncoordinated deformation between concrete cover and top flange appeared during the internal force transmission, making the bonding interface between them resist strong tensile stress and resulting in the debonding failure. After the chemical bond force at the bonding interface failed, the lateral concrete cover was firstly torn at the top flange tip, forming bonding cracks. The trapezoidal failure zone would form in the pure bending zone if bonding cracks developed sufficiently. Increasing the amount of steel fibres could prevent the trapezoidal failure zone from separation. Influenced by debonding failure, the extrusion action between bottom flange and bottom concrete cover was aggravated, generating longitudinal splitting cracks on the bottom surface of specimen.

Sensitive detection of furazolidone and nitrofurantoin by fluorescent nanoprobe coated with 3-mercaptopropionic acid on CdS quantum dots

Cadmium sulfide quantum dots (CdS QDs) were synthesized with 3-mercaptopropionic acid (MPA) as protective agent, which were characterized by TEM, UV–vis, fluorescence, XRD and TGA. Based on the fluorescence quenching of 3-MPA-CdS QDs, the indirect methods for the determination of furazolidone (FZD) and nitrofurantoin (NFT) were established. The interaction between FZD/NFT and CdS QDs was investigated by using fluorescence, resonance light scattering, UV–vis and FT-IR. The analyses of Stern-Volmer and fluorescence lifetime indicated that the two quenching systems were all static. The binding constant (Ka) of FZD/NFT-CdS QDs was 1.20 × 104/1.81 × 104 L/mol at 293 K, respectively. Hydrogen bond or van der Waals force was the main binding force between CdS QDs and drugs. Under optimum experimental conditions, the concentration of FZD/NFT was respectively highly correlated with the fluorescence intensity ratio in the range of 0.27 – 36.03/0.57 – 28.58 μg mL−1. The interference experiments showed that the methods had good selectivity. The limit of detection (LOD) for FZD/NFT was 0.02/0.01 μg mL−1. The contents of FZD and NFT in fish samples were determined, and the recoveries were 97.41–99.52 % and 96.64–100.49 %, respectively.

Fabrication of a biochar-doped monolithic adsorbent and its application for the extraction and determination of coumarins from Angelicae Pubescentis Radix

A monolithic adsorbent was designed aiming to the structure of osthole and columbianadin, and fabricated using diallyl phthalate as the monomer and ethylene dimethacrylate as the crosslinker with the addition of bamboo biochar, via polymerization reaction in a stainless-steel tube. The prepared composite adsorbent packed in the tube was used as a solid-phase extraction column for the extraction and determination of two coumarins (osthole and columbianadin) in Angelicae Pubescentis Radix, combing with a C18 analytical column through an HPLC instrument, which show excellent matrix-removal ability and good selectivity to osthole and columbianadin. Furthermore, the present adsorbent shows good applicability, which was used for the extraction of osthole from Duhuo Jisheng Pill. Compared to the commercial C18 and phenyl adsorbent, the present adsorbent own better selectivity and higher resolution. These results attributed to the enhanced specific surface area (141 m2/g) and enriched interaction sites of the resulting composite adsorbent, due to the doping of bamboo biochar, which can produce hydrogen bond, dipole-dipole, π-π and hydrophobic force interactions with the osthole and columbianadin. The methodology validation indicated that the present method showed good precision and good accuracy, and the composite adsorbent showed good preparative repeatability, which can be reused for no less than 100 times with the relative standard deviation ≤4.6 % (n = 100). The present work provided a simple and efficient method for the extraction and determination osthole and columbianadin from Angelicae Pubescentis Radix.

Improved encapsulation effect and structural properties of whey protein isolate by dielectric barrier discharge cold plasma

The whey protein isolate (WPI) was modified by dielectric barrier discharge cold plasma (DBD) in order to improve its encapsulation efficiency of rutin. In this work, the effect of DBD treatment on structure and physicochemical properties of WPI and the interaction between DBD-treated WPI and rutin were investigated. The results showed that the structural change of WPI leaded to the exposure of internal hydrophobic groups, increasing the interaction site with rutin. The encapsulation efficiency of DBD-treated WPI (30 kV, 30 s) on rutin was improved by 12.42 % compared with control group. The results of multispectral analysis showed that static quenching occurred in the process of interaction between DBD-treated and rutin, hydrogen bond and van der Waals force were the main forces between them. Therefore, DBD treatment can be used as a method to improve the encapsulation efficiency of WPI on hydrophobic active substances.

Recycling enzymatic hydrolysis lignin residues saved cellulase in enzymatic hydrolysis of lignocellulose: An insight from cellulase adsorption mechanism

Enzymatic hydrolysis lignin residues (EHLRs) of lignocellulose usually adsorbs cellulase, which can be recycled and used to replace parts of cellulase in the hydrolysis process. To understand this phenomenon during enzymatic hydrolysis (EH) of sugarcane bagasse (SCB) treated with sulfite (SPORL) and dilute acid (DA), the adsorption characteristics between lignin and cellulase in EHLRs were investigated, focusing on interaction force at molecular level and enzymatic activity. The results revealed that SPORL-EHLR adsorbed more β-glucosidases (β-GLs) through the stronger electrostatic attraction and hydrogen bond force, causing higher cellulase adsorption amount compared to DA-EHLR. Further exploration demonstrated that the cellobiose’s catalytic and binding sites on β-GLs were separated from the binding site of SPORL-EHLR on β-GLs, resulting in minimal inhibition of β-GLs activity when bound to SPORL-EHLR. Furthermore, adding SPORL-EHLR in SCB hydrolysis saved 40% cellulase. This study deepens the understanding of the adsorption behavior between lignin and cellulase.

Unraveling the underlying mechanism of interactions between astaxanthin geometrical isomers and bovine serum albumin

The health benefits of astaxanthin (AST) are related to its geometric isomers. Generally, functional activity is realized by the interactions between active substances and transporters. Hereto, bovine serum albumin (BSA), as a model-binding protein and transporter, is able to recognize and transport isomers of active substances through binding with them. However, differences in the binding mechanism of isomers to BSA may affect the functional activities of isomers through the “binding-transport-activity” chain reaction. Thus, this study sought to elucidate the interactions between AST geometrical isomers and BSA using multi-spectroscopy, surface plasmon resonance and molecular docking. The results showed that Z-AST displayed more interacting amino acid residues and lower thermodynamic parameters than all-E-AST. Meanwhile, the order of binding affinity to BSA was 13Z-AST (1.56 × 10−7 M) > 9Z-AST (2.70 × 10−7 M) > all-E-AST (4.01 × 10−7 M), indicating that Z-AST possessed stronger binding ability to BSA. Moreover, AST isomers were located at the junction between subdomains ⅡA and ⅢA of BSA, and showed the same interaction forces (hydrogen bond and van der Waals force) as well as kinetic processes (slow combination, slow dissociation). These interaction parameters provide valuable insights into their pharmacokinetics in vivo, and it was of great significance to explain the potential differences among AST isomers in functional activities.

Interaction of narcissoside with α-amylase from Bacillus subtilis and Porcine pancreatic by multi-spectral analysis and molecular dynamics simulation.

In this work, interaction mechanism of narcissoside with two α-amylase from Bacillus subtilis (BSA) and Porcine pancreatic (PPA) are comparatively studied by multi-spectral analysis, molecular docking and molecular dynamics simulation. The results prove that narcissoside can statically quench fluorescence of BSA/PPA. Two complexes are mainly formed by hydrogen bond and van der Waals force. With the increase of temperature, the two complexes formed by narcissoside and two enzymes become unstable. At the same experimental temperature, the binding force of narcissoside to PPA is higher than that of BSA. The binding of narcissoside to PPA/BSA increases the hydrophobicity of microenvironment. Moreover, the secondary structure of PPA/BSA is mainly changed by decreasing the α-helix. The optimal binding modes of narcissoside with BSA/PPA are predicted by molecular docking, and the stability of the two complexes is evaluated by molecular dynamics simulations.

Adsorption Behavior of Microplastics as a Carrier of Various Contaminants and Their Ecotoxicity in Aquatic Environment

Objectives : Microplastics are released into the aquatic environment through multiple pathways including runoff, atmospheric sedimentation, aquaculture, and fishing and pose a hazard to organisms. Public concerns regarding microplastics are raising as microplastic pollution increases. A lot of studies have been evaluated the behavior of microplastics in the environment, suggesting that microplastics remain a prolonged period in the environment due to their persistence and can interact with other contaminants. Microplastics as carriers of coexisting contaminants may pose a more severe toxicity to organisms than microplastics alone. In this study, we investigated the behavior of microplastics as carriers of environmental contaminants and introduced a potential ecotoxicity of microplastics carrying other contaminants.Methods : The behavior of microplastics as carriers of contaminants were classified as adsorption mechanisms. Research literature regarding ecological risk of microplastics carrying contaminants was reviewed in papers published between October 2003 and August 2023.Results and Discussion : Adsorption of contaminants onto microplastics are mainly involved in hydrophobic interaction, electrostatic interaction, hydrogen bond, and Van der Waals forces. The co-exposure of microplastics with contaminants to organisms can induce oxidative stress and bioaccumulation and reduce the survival and reproduction rates, chlorophyll content, and photosynthetic efficiency. On the other hand, a few studies reported that the co-exposure of microplastics with contaminants can decrease the toxicity to organisms.Conclusion : This paper provides basic information regarding the adsorption interactions of microplastics with diverse contaminants and their ecological effects on organisms. The contents will help to understand a potential function of microplastics as a carrier of coexisting contaminants in aquatic environment and their biological risk.