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1.
J Phys Chem Lett ; 14(47): 10693-10699, 2023 Nov 30.
Article in English | MEDLINE | ID: mdl-37988698

ABSTRACT

Activated carbon (AC)-based materials have shown promising performance in carbon capture, offering low cost and sustainable sourcing from abundant natural resources. Despite ACs growing as a new class of materials, theoretical guidelines for evaluating their viability in carbon capture are a crucial research gap. We address this gap by developing a hierarchical guideline, based on fundamental gas-solid interaction strength, that underpins the success and scalability of AC-based materials. The most critical performance indicator is the CO2 adsorption energy, where an optimal range (-0.41 eV) ensures efficiency between adsorption and desorption. Additionally, we consider thermal stability and defect sensitivity to ensure consistent performance under varying conditions. Further, selectivity and capacity play significant roles due to external variables such as partial pressure of CO2 and other ambient air gases (N2, H2O, O2), bridging the gap between theory and reality. We provide actionable examples by narrowing our options to methylamine- and pyridine-grafted graphene.

2.
Front Immunol ; 14: 1186258, 2023.
Article in English | MEDLINE | ID: mdl-37283767

ABSTRACT

Introduction: Adenoid hypertrophy is the main cause of obstructive sleep apnea in children. Previous studies have suggested that pathogenic infections and local immune system disorders in the adenoids are associated with adenoid hypertrophy. The abnormalities in the number and function of various lymphocyte subsets in the adenoids may play a role in this association. However, changes in the proportion of lymphocyte subsets in hypertrophic adenoids remain unclear. Methods: To identify patterns of lymphocyte subsets in hypertrophic adenoids, we used multicolor flow cytometry to analyze the lymphocyte subset composition in two groups of children: the mild to moderate hypertrophy group (n = 10) and the severe hypertrophy group (n = 5). Results: A significant increase in naïve lymphocytes and a decrease in effector lymphocytes were found in severe hypertrophic adenoids. Discussion: This finding suggests that abnormal lymphocyte differentiation or migration may contribute to the development of adenoid hypertrophy. Our study provides valuable insights and clues into the immunological mechanism underlying adenoid hypertrophy.


Subject(s)
Adenoids , Sleep Apnea, Obstructive , Child , Humans , Lymphocyte Subsets/pathology , Lymphocyte Count , Hypertrophy
3.
Angew Chem Int Ed Engl ; 62(26): e202302765, 2023 Jun 26.
Article in English | MEDLINE | ID: mdl-37114300

ABSTRACT

Hydrogels with pure hydrophilic network have received much attention due to their excellent low frictional behavior. However, the lubrication performance of hydrogels is not satisfied under high-speed condition due to the energy dissipation caused by adsorbed polymer chains as well as the failure of lubricating mechanisms accompanied by the transition of lubrication regime. In this work, interpenetrating double-network organohydrogels were constructed by combining hydrophilic and oleophilic polymer networks to modify the physiochemical properties of surface polymer chains, especially the chain mobility. The oleophilic polymer network spatially restricting the mobility of the swollen hydrophilic network in water, resulted in a low coefficient of friction (ca. 0.01) compared with conventional hydrogels at high speed (0.1 m s-1 ). Meanwhile, the organohydrogels had superior wear resistance, with almost no wear observed on the sliding track after 5 k cycles of rubbing at high speed. The design concept of organohydrogels can be extended to a variety of low-wear, highly-lubricating materials.


Subject(s)
Hydrogels , Polymers , Polymers/chemistry , Lubrication , Hydrophobic and Hydrophilic Interactions , Friction , Hydrogels/chemistry
4.
Small ; 18(50): e2200272, 2022 Dec.
Article in English | MEDLINE | ID: mdl-36319476

ABSTRACT

For most electrodes fabricated with carbon, transition metal compounds, or conductive polymers, the capacitance may deteriorate with cyclic charging and discharging. Thus, an electrochemically stable supercapacitor has long been pursued by researchers. In this work, the hierarchical structure of balsa wood is preserved in the converted carbon which is used as a supporting framework to fabricate electrodes for supercapacitors. Well-grown carbon nanotubes (CNTs) on interior and exterior surfaces of balsa carbon channels provide two advantages including 1) offering more specific surface area to boost capacitance via electric double layer capacitance and 2) offering more active Fe and Ni sites to participate in the redox reaction to enhance capacitance of the balsa carbon/CNTs electrode. The balsa carbon/CNTs demonstrate an excellent area capacitance of 1940 mF cm-2 . As active sites on Ni and Fe catalysts and inner walls of CNTs are gradually released, the capacitance increases 66% after 4000 charge-discharge cycles. This work brings forward a strategy for the rational design of high-performance biomass carbon coupled with advanced nanostructures for energy storage.

5.
J Oncol ; 2022: 6243165, 2022.
Article in English | MEDLINE | ID: mdl-36090905

ABSTRACT

Objective: Arsenic trioxide (ATO) has been effectively used for the treatment of hematological malignancies and some solid tumors, while ATO effects were not tested clinically in epithelial ovarian cancer (EOC). Methods: Patients with primary or secondary platinum-resistant EOC were enrolled from October 2015 to December 2019. Patients were mainly treated with ATO-based combined sequential chemotherapy as follows: Regimen 1 (ATO combined taxanes weekly therapy); Regimen 2 (ATO + taxanes + 5-fluorouracil + adriamycin ± bevacizumab sequential chemotherapy), for 5 patients platinum-free interval >12 months, added oxaliplatin). Prespecified end points in this cohort included confirmed best overall response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety. Results: A total of 33 patients were enrolled in this study. After a median follow-up time of 22.1 months (range 5.5-42.9 months), ORR was 42% and DCR was 85%. The overall PFS was 9.5 months (range 1-38.4 months). The main side effect was myelosuppression. Conclusions: ATO-based sequential combined chemotherapy is effective for primary and recurrent drug-resistant EOC patients in clinical phase II trials. The associated side effects could be controlled, while further study is needed.

6.
Eur Arch Otorhinolaryngol ; 279(3): 1349-1355, 2022 Mar.
Article in English | MEDLINE | ID: mdl-34104981

ABSTRACT

PURPOSE: This study aimed to detect the epidemiological relevance between adenoid hypertrophy (AH) and rhinosinusitis, and AH and allergic rhinitis (AR) through an Internet search. METHODS: Internet search query data from January 2011 to December 2019 in China were retrieved from the Baidu Index (BI). Spearman's correlation coefficients were used to detect the correlation among the search volumes of AH, rhinosinusitis, and AR. We also collected search data from the first 5 months of 2020, when quarantine was implemented in China due to the coronavirus disease 2019 epidemic. Then, we compared the search data to those obtained during the same period in 2019 to assess the effects of isolation on AH and AR. RESULTS: Statistically significant relevance was found between the search variations of AH and rhinosinusitis during 2011-2019 (R = 0.643, P < 0.05). However, the relationship between AH and AR was weak (R = - 0.239, P < 0.05) and that between rhinosinusitis and AR (R = - 0.022, P > 0.05) was not relevant. The average monthly search volume of AH and rhinosinusitis had a strong correlation (R = 0.846, P < 0.01), but AH and AR and rhinosinusitis and AR were not correlated (R = - 0.350, P > 0.05; R = - 0.042, P > 0.05, respectively). AH and rhinosinusitis search volumes decreased consistently during the first 5 months of 2020 (isolation), whereas that for AR increased during January-February. CONCLUSION: AH had an epidemiological relationship with rhinosinusitis, which was not consistent with AR. The decrease in public gathering effectively reduced the morbidities of AH and rhinosinusitis but not those of AR.


Subject(s)
Adenoids , COVID-19 , Rhinitis, Allergic , COVID-19/epidemiology , Humans , Hypertrophy/epidemiology , Internet , Rhinitis, Allergic/diagnosis , Rhinitis, Allergic/epidemiology , SARS-CoV-2
7.
Acta Pharm Sin B ; 11(9): 2914-2923, 2021 Sep.
Article in English | MEDLINE | ID: mdl-34589404

ABSTRACT

Cyclodextrin metal-organic framework (CD-MOF) as a highly porous supramolecular carrier could be one of the solutions to the insolubility of isosteviol (STV). The solubility of STV was lower than 20.00 ng/mL at pH 1.0 and pH 4.5, whilst its solubility increased to 20,074.30 ng/mL at pH 6.8 and 129.58 ng/mL in water with a significant pH-dependence. The in vitro release profiles of STV from STV@CD-MOF (0.5:1) were pH-independent in distinct pH media and closed to be thoroughly released but no such release profiles were observed for STV@CD-MOF (1:1) owing to nanoclusters formation. The bioavailability of STV@CD-MOF (1:1) in rats was 8.67-fold higher than that of STV, and was 1.32- and 1.27-fold higher than that of STV@CD and STV@CD-MOF (0.5:1). Our results indicated that the inclusion mechanism played a primary role when STV in CD-MOF was at a low loading ratio, while the increasement in bioavailability at a high loading ratio, which was attributed to the nanocluster mechanism. This was confirmed by molecular simulation. In conclusion, CD-MOF is a promising system for STV loading, overcoming the insolubility and to improve the bioavailability of this natural compound.

8.
Nature ; 594(7861): 57-61, 2021 06.
Article in English | MEDLINE | ID: mdl-34079133

ABSTRACT

If a bulk material can withstand a high load without any irreversible damage (such as plastic deformation), it is usually brittle and can fail catastrophically1,2. This trade-off between strength and fracture toughness also extends into two-dimensional materials space3-5. For example, graphene has ultrahigh intrinsic strength (about 130 gigapascals) and elastic modulus (approximately 1.0 terapascal) but is brittle, with low fracture toughness (about 4 megapascals per square-root metre)3,6. Hexagonal boron nitride (h-BN) is a dielectric two-dimensional material7 with high strength (about 100 gigapascals) and elastic modulus (approximately 0.8 terapascals), which are similar to those of graphene8. Its fracture behaviour has long been assumed to be similarly brittle, subject to Griffith's law9-14. Contrary to expectation, here we report high fracture toughness of single-crystal monolayer h-BN, with an effective energy release rate up to one order of magnitude higher than both its Griffith energy release rate and that reported for graphene. We observe stable crack propagation in monolayer h-BN, and obtain the corresponding crack resistance curve. Crack deflection and branching occur repeatedly owing to asymmetric edge elastic properties at the crack tip and edge swapping during crack propagation, which intrinsically toughens the material and enables stable crack propagation. Our in situ experimental observations, supported by theoretical analysis, suggest added practical benefits and potential new technological opportunities for monolayer h-BN, such as adding mechanical protection to two-dimensional devices.

9.
Parasit Vectors ; 13(1): 611, 2020 Dec 09.
Article in English | MEDLINE | ID: mdl-33298142

ABSTRACT

BACKGROUND: Haem is a key metabolic factor in the life cycle of the malaria parasite. In the blood stage, the parasite acquires host haemoglobin to generate amino acids for protein synthesis and the by-product haem for metabolic use. The malaria parasite can also synthesize haem de novo on its own. Plasmodium falciparum-specific histidine-rich protein 2 (PfHRP2) has a haem-binding site to mediate the formation of haemozoin, a biocrystallized form of haem aggregates. Notably, the gene regulates the mechanism of haemoglobin-derived haem metabolism and the de novo haem biosynthetic pathway in the Pfhrp2-disrupted parasite line during the intraerythrocytic stages. METHODS: The CRISPR/Cas9 system was used to disrupt the gene locus of Pfhrp2. DNA was extracted from the transgenic parasite, and PCR, Southern blotting and Western blotting were used to confirm the establishment of transgenic parasites. RNA-sequencing and comparative transcriptome analysis were performed to identify differences in gene expression between 3D7 and Pfhrp2--3D7 parasites. RESULTS: Pfhrp2- transgenic parasites were successfully established by the CRISPR/Cas9 system. A total of 964, 1261, 3138, 1064, 2512 and 1778 differentially expressed genes (DEGs) were identified in the six comparison groups, respectively, with 373, 520, 1499, 353, 1253 and 742 of these DEGs upregulated and 591, 741, 1639, 711, 1259 and 1036 of them downregulated, respectively. Five DEGs related to haem metabolism and synthesis were identified in the comparison groups at six time points (0, 8, 16, 24, 32, and 40 h after merozoite invasion). The genes encoding delta-aminolevulinic acid synthetase and ferrochelatase, both related to haem biosynthesis, were found to be significantly upregulated in the comparison groups, and those encoding haem oxygenase, stromal-processing peptidase and porphobilinogen deaminase were found to be significantly downregulated. No GO terms were significantly enriched in haem-related processes (Q value = 1). CONCLUSION: Our data revealed changes in the transcriptome expression profile of the Pfhrp2--3D7 parasite during the intraerythrocytic stages. The findings provide insight at the gene transcript level that will facilitate further research on and development of anti-malaria drugs.


Subject(s)
Antigens, Protozoan/genetics , Antigens, Protozoan/metabolism , Heme/metabolism , Plasmodium falciparum/metabolism , Protozoan Proteins/genetics , Protozoan Proteins/metabolism , Animals , Antimalarials/metabolism , Base Sequence , Binding Sites , CRISPR-Cas Systems , Diagnostic Tests, Routine , Gene Targeting , Hemoglobins , Humans , Life Cycle Stages , Malaria, Falciparum/parasitology , Plasmodium falciparum/genetics , Polymerase Chain Reaction , Transcriptome
10.
Int J Hypertens ; 2020: 7109502, 2020.
Article in English | MEDLINE | ID: mdl-32328302

ABSTRACT

OBJECTIVES: The association between accessory renal artery (ARA) and hypertension remains not fully understood. We observed the association between ARA and clinical characteristics among middle-aged patients with primary hypertension. METHODS: One hundred and sixty-two middle-aged (mean 39.82 ± 10.25 years, 58.0% male) patients with primary hypertension were enrolled, and patients underwent Computed Tomography Angiography (CTA) of renal arteries, ambulatory blood pressure monitor (ABPM), echocardiography, physical examination, and routine blood chemistry examinations. According to the CTA results, patients were divided into a non-ARA (n = 108) and ARA (n = 54) group. Direct renin concentration (DRC), plasma aldosterone concentration (PAC), ABPM, echocardiography, creatinine, and glomerular filtration rate were compared between the two groups. RESULTS: DRC (mU/L) (11.21 (5.34, 20.87) vs. 18.24 (10.32, 33.59), P=0.002) was significantly higher in the ARA group than in the non-ARA group. However, PAC (ng/dL) (98.30 (67.30, 134.00) vs. 116.50 (78.80, 137.25), P=0.103) was similar between these two groups. ABPM (mmHg) results showed that daytime (146.75 ± 17.04/95.86 ± 11.39 vs. 155.50 ± 14.76/100.48 ± 10.69, P < 0.05), night time (133.44 ± 17.50/85.28 ± 12.80 vs. 139.81 ± 14.64/89.83 ± 11.21, P < 0.05), and 24 h blood pressure (143.95 ± 15.99/93.90 ± 11.78 vs. 152.07 ± 13.85/98.11 ± 10.36, P < 0.05) were significantly higher in the ARA group than in the non-ARA group. Accordingly, echocardiographic-derived posterior left ventricular wall thickness value was higher in the ARA group than in the non-ARA group. CONCLUSION: ARA is related to higher blood pressure and higher direct renin concentration in middle-aged patients with primary hypertension, and these patients deserve stricter blood pressure control. Our results provide important evidence for that ARA is a cause of hypertension and target organs damages.

11.
RSC Adv ; 10(30): 17438-17443, 2020 May 05.
Article in English | MEDLINE | ID: mdl-35515587

ABSTRACT

The strong force that originates from breaking covalent bonds can be easily quantified through various testing platforms, while weak interfacial sliding resistance (ISR), originating from hydrogen bonding or van der Waals (vdW) forces, is very challenging to measure. Facilitated by an in-house nanomechanical testing system, we are able to precisely quantify and clearly distinguish the interfacial interactions between individual carbon fibers and several substrates governed by either hydrogen bonding or vdW forces. The specific ISR of the interface dominated by vdW forces is 3.55 ± 0.50 µN mm-1 and it surprisingly increases to 157.86 ± 44.18 µN mm-1 if the interface is bridged by hydrogen bonding. The ad hoc studies demonstrate that hydrogen bonding rather than vdW forces has great potential in sewing the interface if both surfaces are supportive of the formation of hydrogen bonds. The findings will enlighten the engineering of interfacial interactions and further mediate the entire mechanical performance of structures.

12.
Int J Hypertens ; 2019: 2195796, 2019.
Article in English | MEDLINE | ID: mdl-31354984

ABSTRACT

OBJECTIVES: Aldosterone-to-plasma renin activity ratio (ARR) derived from traditional radioimmunoassay (RIA) is widely used to detect primary aldosteronism (PA). Recently, aldosterone-to-direct renin concentration ratio (ADRR), which is calculated by direct renin concentration (DRC) measured by chemiluminescent immunoassay (CLIA), is proposed to replace ARR as the screening test method for PA. The purpose of the present study was to estimate the diagnostic accuracy and cutoff value of ADRR as screening test for PA. METHODS: 450 hypertensive patients with suspected PA referred to hypertension center of our department were enrolled and underwent screening and confirmatory tests of PA. Plasma renin activity (PRA), DRC, and plasma aldosterone concentration (PAC) were measured by both RIA and CLIA simultaneously during screening and confirmatory test. RESULTS: 386 patients were diagnosed as primary hypertension (PH) and 64 patients as PA. Within-patient correlation between PRA and DRC (r=0.88, P<0.001) and correlation between PAC measured by RIA and CLIA were high (r=0.80, P<0.001). The optimal cutoff value of ADRR was 2.93 (ng/dL)/(mU/L), sensitivity 80.33%, and specificity 92.11%. The optimal cutoff value of ARR was 25.28 (ng/dL)/(ng/mL/h), sensitivity 76.92%, and specificity 93.38%. CONCLUSION: The optimal cutoff values of ADRR and ARR for screening PA are defined in this patient cohort with high sensitivity and specificity. Our results are of clinical importance for accelerating the extensive use of ADRR as a screening test for PA in daily practice.

13.
Medicine (Baltimore) ; 98(18): e15436, 2019 May.
Article in English | MEDLINE | ID: mdl-31045809

ABSTRACT

RATIONALE: de Winter electrocardiograph (ECG) pattern signifies proximal left anterior descending coronary artery (LAD) occlusion and extensive anterior myocardial infarction, and it is found in about 2% of patients with proximal LAD occlusion. However, it is often unrecognized by physicians. In this case report, we present a patient with chest pain but showing an atypical and delayed de Winter ECG pattern. PATIENT CONCERNS: A previously healthy 61-year-old man attended our emergency department with chest pain radiating to the left arm and back for 4 hours, who was without serious cardiovascular risk factors. ECG at emergency department showed no significant changes. High-sensitivity cardiac troponin I (hs-cTnI) was within normal limit. DIAGNOSIS: At 5 hours after onset, ECG showed significant upsloping ST depression at J point in precordial leads V3 to V6, slight ST elevation in aVR and depression in inferior leads, and hs-cTnI peaked at 2.610 µg/L. The diagnosis of de Winter ECG pattern was confirmed by coronary angiography with an occlusion of the proximal LAD. INTERVENTIONS: A stent was implanted through percutaneous coronary intervention. OUTCOMES: The patient's chest pain was relieved without further increase of hs-cTnI. ECG after procedure showed ST segment back to baseline in leads V4 to V6, but persistent ST elevation in V1 to V3 with QS or Q wave. LESSONS: Timely diagnosis of de Winter ECG pattern is very important, especially the atypical and delayed ECG changes. It should be treated as ST elevation myocardial infarction equivalent and deserves emergent revascularization therapy.


Subject(s)
Chest Pain/etiology , Coronary Occlusion/diagnosis , Electrocardiography , Coronary Occlusion/surgery , Humans , Male , Middle Aged , Stents , Time Factors , Troponin I
14.
ACS Nano ; 12(8): 7901-7910, 2018 Aug 28.
Article in English | MEDLINE | ID: mdl-30051705

ABSTRACT

Perfect graphene is believed to be one of the strongest materials, yet its resistance to fracture is much less impressive. The modest fracture toughness is thought to be related to the general brittle nature in the fracture process of graphene and its two-dimensional (2D) analogous. The brittleness also makes it extremely difficult to assess mechanical properties of 2D materials. The introduction of carbon nanotubes (CNTs) into bulk materials has proven to be a widely accepted method for toughening and strengthening materials. To date, such toughening effect of CNTs on 2D materials is largely unknown. A unique material, rebar graphene, has been synthesized that consists of CNTs embedded in graphene. In this study, by implementing a "dry" transfer technique, the freely suspended rebar graphene was systematically tested under uniaxial tension mode inside a scanning electron microscope. Our combined experiments and molecular dynamics simulations confirm that the embedded CNTs divert and bridge the propagating crack and provide a toughening mechanism for the material. Our work identifies a promising extrinsic toughening strategy for 2D materials and provides mechanistic insights into the fracture process of graphene hybrid material.

15.
Nanoscale ; 10(31): 14938-14946, 2018 Aug 09.
Article in English | MEDLINE | ID: mdl-30046774

ABSTRACT

The electrical behaviors under mechanical deformation of an aligned single-walled carbon nanotube (SWCNT) film nanocomposite have been systematically investigated in this work. Electrical signals along the CNT axis (‖) and perpendicular to the CNT axis (⊥) follow a specific pattern, which enables the mechanical motion to be determined by vector analysis of such signals. The unique electrical behaviors of the sandwiched nanocomposites originate from the anisotropic characteristics of the CNT films. By combining in situ mechanical investigation with a coarse-grained molecular dynamics simulation, the shearing effect between SWCNTs is found to play a key role in stress-transfer along the ‖ direction, resulting in arc-shape cracks, while the peeling effect is dominant along the ⊥ direction, leading to unifom SWCNT bar bridging at cracks. The fabricated CNT based sandwiched nanocomposite is believed to have great potential in building flexible all-direction sensors.

16.
Adv Sci (Weinh) ; 4(9): 1700076, 2017 09.
Article in English | MEDLINE | ID: mdl-28932666

ABSTRACT

Graphene/hexagonal boron nitride (h-BN) monolayer in-plane heterostructure offers a novel material platform for both fundamental research and device applications. To obtain such a heterostructure in high quality via controllable synthetic approaches is still challenging. In this work, in-plane epitaxy of graphene/h-BN heterostructure is demonstrated on Cu-Ni substrates. The introduction of nickel to copper substrate not only enhances the capability of decomposing polyaminoborane residues but also promotes graphene growth via isothermal segregation. On the alloy surface partially covered by h-BN, graphene is found to nucleate at the corners of the as-formed h-BN grains, and the high growth rate for graphene minimizes the damage of graphene-growth process on h-BN lattice. As a result, high-quality graphene/h-BN in-plane heterostructure with epitaxial relationship can be formed, which is supported by extensive characterizations. Photodetector device applications are demonstrated based on the in-plane heterostructure. The success will have important impact on future research and applications based on this unique material platform.

17.
Sci Rep ; 7(1): 7098, 2017 08 02.
Article in English | MEDLINE | ID: mdl-28769104

ABSTRACT

There is a longstanding challenge to disperse metal nanoparticles uniformly in bulk polymers for widespread applications. Conventional scale-down techniques often are only able to shrink larger elements (such as microparticles and microfibers) into micro/nano-elements (i.e. nanoparticles and nanofibers) without much altering their relative spatial and size distributions. Here we show an unusual phenomenon that tin (Sn) microparticles with both poor size distribution and spatial dispersion were stretched into uniformly dispersed and sized Sn nanoparticles in polyethersulfone (PES) through a stack and draw technique in thermal drawing. It is believed that the capillary instability plays a crucial role during thermal drawing. This novel, inexpensive, and scalable method overcomes the longstanding challenge to produce bulk polymer-metal nanocomposites (PMNCs) with a uniform dispersion of metallic nano-elements.

18.
Nanoscale ; 9(8): 2916-2924, 2017 Feb 23.
Article in English | MEDLINE | ID: mdl-28181613

ABSTRACT

Hierarchically organized three-dimensional (3D) carbon nanotubes/graphene (CNTs/graphene) hybrid nanostructures hold great promises in composite and battery applications. Understanding the junction strength between CNTs and graphene is crucial for utilizing such special nanostructures. Here, in situ pulling an individual CNT bundle out of graphene is carried out for the first time using a nanomechanical tester developed in-house, and the measured junction strength of CNTs/graphene is 2.23 ± 0.56 GPa. The post transmission electron microscopy (TEM) analysis of remained graphene after peeling off CNT forest confirms that the failure during pull-out test occurs at the CNT-graphene junction. Such a carefully designed study makes it possible to better understand the interfacial interactions between CNTs and graphene in the 3D CNTs/graphene nanostructures. The coupled experimental and computational effort suggests that the junction between the CNTs and the graphene layer is likely to be chemically bonded, or at least consisting of a mixture of chemical bonding and van der Waals interactions.

19.
Adv Mater ; 29(2)2017 Jan.
Article in English | MEDLINE | ID: mdl-27809368

ABSTRACT

An in situ quantitative tensile testing platform is developed to enable the uniform in-plane loading of a freestanding membrane of 2D materials inside a scanning electron microscope. The in situ tensile testing reveals the brittle fracture of large-area MoSe2 crystals and measures their fracture strength for the first time.

20.
Nanotechnology ; 27(36): 364004, 2016 Sep 09.
Article in English | MEDLINE | ID: mdl-27483462

ABSTRACT

Hexagonal boron nitride (h-BN) atomic layers were utilized as a passivation coating in this study. A large-area continuous h-BN thin film was grown on nickel foil using a chemical vapor deposition method and then transferred onto sputtered copper as a corrosion passivation coating. The corrosion passivation performance in a Na2SO4 solution of bare and coated copper was investigated by electrochemical methods including cyclic voltammetry (CV), Tafel polarization and electrochemical impedance spectroscopy (EIS). CV and Tafel analysis indicate that the h-BN coating could effectively suppress the anodic dissolution of copper. The EIS fitting result suggests that defects are the dominant leakage source on h-BN films, and improved anti-corrosion performances could be achieved by further passivating these defects.

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