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1.
Carbohydr Polym ; 333: 121951, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38494216

RESUMEN

Passive daytime radiative cooling (PDRC) as a zero-energy-consumption cooling technique offers rich opportunities in reducing global energy consumption and mitigating CO2 emissions. Developing high-performance PDRC coolers with practical applicability based on sustainable materials is of great significance, but remains a big challenge. Herein, polyvinyl alcohol (PVA) and esterified cellulose (EC) extracted from sawdust were used as raw materials to construct foams by using a dual-crosslinking assisted-unidirectional freeze-drying strategy followed by hydrophobic surface modification. The resultant PVA/EC (PEC) foams with ideal hierarchical macropore structure displayed various excellent features, such as low thermal conductivity (26.2 mW·m-1·K-1), high solar reflectance (95 %) and infrared emissivity (0.97), superhydrophobicity as well as high mechanical properties. The features allowed the PEC foams to be used as radiative coolers with excellent PDRC performance and thermal insulating materials. A maximum sub-ambient temperature drops of 10.2 °C could be achieved for optimal PEC foams. Building simulations indicated that PEC foams could save 55.8 % of the energy consumption for Xi'an. Our work would give inspiration for designing various types of PDRC coolers, including but certainly not limited to foams-based radiative coolers.

2.
ACS Appl Mater Interfaces ; 16(8): 11134-11144, 2024 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-38354312

RESUMEN

Recently, materials with superlubricity captured widespread attention on account of their great potential in energy savings and environmental protection. However, certain issues still remain to be solved for the traditional materials, such as the dependence on strict conditions and an unstable superlubricity state. Herein, a long-term stable superlubricity coating was prepared using a low-cost and simple method via an epoxy-based coating with polydimethylsiloxane (PDMS) brushes under silicone oil (SO) lubrication conditions. Compared with the pure epoxy resin matrix, the friction coefficient and wear track width of the superlubricity coating with the optimal amount of 6 wt % PDMS are reduced to 0.006 and 50.9 µm (reduced by 10-fold and 5.6-fold decrease, respectively). In addition, the coating can maintain a stable superlubricity state during a 5 h tribological test. The superlubricity of the coating results from the synergistic lubrication effect of the PDMS brush and SO. First, PDMS brushes with high-stretched conformation due to the swelling effect of the SO can significantly reduce friction. Second, a stable oil film is generated between the contact surfaces, which significantly improves the frictional performance. Moreover, the PDMS incorporated into the coating matrix, along with oil-swelling PDMS brushes on the surface, is highly beneficial for enhancing corrosion resistance of the epoxy resin matrix. Such an epoxy-based coating with long-term stable superlubricity is considered as a potential lubricating and protective surface for tribological components for long-term service.

3.
J Org Chem ; 89(5): 3453-3470, 2024 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-38335461

RESUMEN

In the present study, we successfully developed an efficient thiocyanation of carbonyl compounds by using low-toxicity and inexpensive ammonium thiocyanate as the thiocyanate source under visible light in air (O2) at room temperature. This unified strategy is very facile for thiocyanation of various carbonyl compound derivatives (ß-keto esters, ß-keto amides, pyrazo-5-ones, isoxazol-5-ones, etc.). More importantly, the reaction proceeded smoothly without the addition of a photocatalyst and strong oxidant, ultimately minimizing the production of chemical waste. Furthermore, this green and sustainable synthetic chemistry can be used in the late-stage functionalization (LSF) of biorelevant compounds, which offers unique opportunities to achieve smooth and clean thiocyanation of drugs under mild reaction conditions.

4.
ACS Nano ; 18(3): 2395-2408, 2024 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-38194614

RESUMEN

The development of high-energy-density Li-S batteries (LSBs) is still hindered by the disturbing polysulfide shuttle effect. Herein, with clever combination between "high entropy" and MXene, an HE-MXene doped graphene composite containing multiple element quasi-atoms as bifunctional mediator for separator modification (HE-MXene/G@PP) in LSBs is proposed. The HE-MXene/G@PP offers high electrical conductivity for fast lithium polysulfide (LiPS) redox conversion kinetics, abundant metal active sites for efficient chemisorption with LiPSs, and strong lipophilic characteristics for uniform Li+ deposition on lithium metal surface. As demonstrated by DFT theoretical calculations, in situ Raman, and DRT results successively, HE-MXene/G@PP efficiently captures LiPSs through synergistic modulation of the cocktail effect and accelerates the LiPSs redox reaction, and the lattice distortion effect effectively induces the homogeneous deposition of dendritic-free lithium. Therefore, this work achieves excellent long-term cycling performance with a decay rate of 0.026%/0.031% per cycle after 1200 cycles at 1 C/2 C. The Li||Li symmetric cell still maintains a stable overpotential after 6000 h under 40 mA cm-2/40 mAh cm-2. Furthermore, it delivers favorable cycling stability under 7.8 mg cm-2 and a low E/S ratio of 5.6 µL mg-1. This strategy provides a rational approach to resolve the sulfur cathode and lithium anode problems simultaneously.

5.
Adv Mater ; 36(9): e2307967, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37910074

RESUMEN

The rapid charge recombination, low selectivity for two-electron oxygen reduction reaction (ORR), and limited O2 diffusion rate hinder the practical applications of photocatalytic H2 O2 generation. Herein, a triphase photocatalytic system in which the H2 O2 generation occurs at the air-liquid-solid joint interfaces is developed, using polymeric carbon nitride (PCN). The introduction of pyrrole units and cyano group into PCN can promote the activation of oxygen molecules and facilitate the spatial separation of HOMO and LUMO orbits, hence improving the charge carrier separation efficiency and enhancing the formation of H2 O2 . Importantly, the gas-liquid-solid triphase interface system allows for the rapid transport of oxygen from the air to the reaction interface, overcoming the low solubility and slow diffusion of oxygen in the water in conventional liquid reaction systems. The triphase system shows a benchmark H2 O2 generation rate over PCN-based materials in pure water (2063.21 µmol g-1 h-1 ), which is an approximate tenfold enhancement as compared to powder photocatalyst (215.44 µmol g-1 h-1 ). Simulation and electrochemical tests reveal that the rapid oxygen diffusion rate of triphase interface can promote charge separation and provide more O2 to generate H2 O2 . This work provides a promising strategy for constructing an efficient and sustainable H2 O2 production system.

6.
Adv Mater ; 36(11): e2308257, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38102857

RESUMEN

The development of Li-free anodes to inhibit Li dendrite formation and provide high energy density Li batteries is highly applauded. However, the lithiophobic interphase and heterogeneous Li deposition hindered the practical application. In this work, a 20 nm ultra-sleek high entropy alloy (HEA, NiCdCuInZn) tights loaded with HEA nanoparticles are developed by a thermodynamically driven phase transition method on the carbon fiber (HEA/C). Multiple Li+ transport paths and abundant active sites are enabled by the cocktail effect of different constituent elements in HEA. These active sites with gradient absorption energies (-3.18 to -2.03 eV) facilitate selective binding, providing a low barrier for homogeneous Li nucleation. Simultaneously, multiple transport paths promote Li diffusion behavior with uniform Li deposition. Thus, the HEA/C achieves high reversibility of Li plating/stripping processes over 2000 cycles with a coulombic efficiency of 99.6% at 5 mA cm-2 /1 mAh cm-2 in asymmetric cells, as well as over 7200 h at 60 mA cm-2 /60 mAh cm-2 in symmetric cells. Moreover, the anode-free full cell with the HEA/C host has an average coulombic efficiency of 99.5% at 1 C after 160 cycles. This advanced HEA structure design shows a favorable potential application for anode-free Li metal batteries.

7.
ACS Appl Mater Interfaces ; 16(1): 1451-1460, 2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38112199

RESUMEN

Hydrogels with excellent mechanical flexibility are widely used in flexible electronic devices. However, it is difficult to meet further applications of high-power integrated flexible electronics as a result of their low thermal conductivity. Herein, highly thermally conductive composite hydrogels with a solid-liquid interpenetrating thermal conductivity network are constructed by aromatic polyamide nanofibers (ANF) and fluorinated graphene (FG) reinforced poly(vinyl alcohol) (PVA) and cross-linked by tannic acid (TA) solution immersion to obtain a hydrogel with a double cross-linked network. The PVA-ANF-FG3T-11.1% composite hydrogel exhibits good mechanical properties compared to PVA-ANFT, with a tensile modulus of up to 0.89 MPa, a tensile strength of up to 1.23 MPa, and an energy of rupture of up to 3.45 MJ cm-3, which is mainly attributed to the multihydrogen bonding interactions in the composite hydrogel. In addition, the friction coefficient of the PVA-ANF-FG3T-11.1% composite hydrogel is 0.178, making it suitable for use in high-friction coefficient applications. The thermal conductivity of the PVA-ANF-FG3T-11.1% composite hydrogel is 1.42 W m-1 K-1, which is attributed to the synergistic effect of the solid thermal conductivity network and the liquid convection network, resulting in a high thermal conductivity of the composite hydrogel. The high thermal conductivity of the PVA-ANF-FG3T-11.1% composite hydrogel shows great potential for flexible wearable electronics and cooling paste applications.

8.
ACS Appl Mater Interfaces ; 16(1): 1794-1804, 2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38117240

RESUMEN

Salt deposition and pollutant enrichment greatly hamper efficient and sustainable water production for a solar evaporator. Inspired by the desert beetle, a dual-region hydrophobic graphene/hydrophilic titanium dioxide (TiO2) aerogel (GTA) with internal hydrophilic-hydrophobic hybrid wettability structure is prepared via a facile freeze-drying and thermal reduction method. The evaporator shows adjustable wettability, optimized water content, and a low energy loss in the evaporation process. Simultaneously, the hybrid wetting structure in aerogel subjects salt to a dynamic crystallization-dissolution process to prevent salt deposition. The GTA solar evaporator achieves an evaporation rate of 1.52 kg·m-2·h-1 with a 91.02% efficiency under 1 sun irradiation. Furthermore, GTAs achieve a stable evaporation rate in high salinity brine (25 wt % NaCl) under 1 sun irradiation for 100 h, which could compete well with other most advanced photothermal evaporation materials. Moreover, the synergistic effect of graphene and TiO2 endows GTAs with excellent photocatalytic degradation and self-cleaning properties, which can effectively reduce the enrichment of contaminants on the evaporator. Therefore, GTA evaporators can efficiently and stably obtain clean water from seawater and wastewater, which provides a feasible strategy for the purification of complex wastewater.

9.
Psychol Res Behav Manag ; 16: 2367-2381, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37404575

RESUMEN

Purpose: Based on ego depletion theory and interaction ritual theory, this research explores the impact of compulsory citizenship behavior on new-generation knowledge workers' job performance via the mediating role of ego depletion and the moderating role of relational energy employees experienced in interactions with coworkers. Methods: Two studies were conducted to explore the impact of compulsory citizenship behavior on job performance. Study 1 used a 10-day daily diary Survey (N=112) and Study 2 used a questionnaire survey conducted multiple times (N=356) to test the hypotheses. Results: The results of Study 1 and Study 2 were almost convergent. Compulsory citizenship behavior had a negative effect on job performance through the mediating effect of ego depletion. In addition, relational energy negatively moderated the effect of compulsory citizenship behavior on ego depletion and negatively moderated the mediating effect of ego depletion between compulsory citizenship behavior and job performance. Conclusion: The results deepen our understanding of the mechanism underlying the effect of compulsory citizenship behavior on job performance from the theoretical perspective of psychological energy, and also provide practical implications on how to manage new-generation knowledge employees' work behavior and job performance.

10.
Psychol Res Behav Manag ; 16: 2517-2531, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37431432

RESUMEN

Purpose: This study explored the J-shaped effect of compulsory citizenship behavior on counterproductive work behavior of new generation employees, as well as the separate and joint moderating effects of trust and felt trust on the J-shaped relationship between compulsory citizenship behavior and counterproductive work behavior. Methods: Three waves of data were collected from 659 new generation employees in China. A self-report method was used to measure compulsory citizenship behavior, counterproductive work behavior, trust and felt trust. Then, based on the cognitive appraisal theory of stress and social information processing theory, a nonlinear model was constructed and tested. Results: (1) Compulsory citizenship behavior had a J-shaped effect on job performance. That is, when the compulsory citizenship behavior level was lower, the effect of compulsory citizenship behavior on counterproductive work behavior was not significant; but when it increased to medium and higher levels, the effect was significant and stronger. (2) The moderating effect of trust (employees' perceived trust in leader) or felt trust (employees' perception of being trusted by leader) was significant. That is, when trust or felt trust was lower, the J-shaped effect was stronger; conversely, the J-shaped effect was weak. (3) The joint moderating effect of trust and felt trust was significant. That is, when trust was high, the moderation effect of felt trust was significant; conversely, the moderation effect of felt trust was not significant. Conclusion: The results identify the nonlinear effect of compulsory citizenship behavior through exploring the J-shaped effect of compulsory citizenship behavior on counterproductive work behavior and the boundary conditions in the nonlinear relationship. Meanwhile, the study provide implications for organizations regarding how to manage employees' work behavior.

11.
ACS Appl Mater Interfaces ; 15(22): 27223-27233, 2023 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-37218624

RESUMEN

With the rapid development of miniaturization and high-power portable electronics, the accumulation of undesired heat can degrade the performance of electronic devices and even cause fires. Therefore, multifunctional thermal interface materials that combine high thermal conductivity and flame retardancy remain a challenge. Herein, an ILC (ionic liquids crystal)-armored boron nitride nanosheet (BNNS) with flame retardant functional groups was first developed. The high in-plane orientation structure aerogel film made of such an ILC-armored BNNS and aramid nanofiber and polyvinyl alcohol matrix through directional freeze-drying and mechanical pressing exhibits strong anisotropy thermal conductivity (λ// of 17.7 W m-1 K-1 and λ⊥ of 0.98 W m-1 K-1). In addition, the highly oriented IBAP aerogel films have excellent flame retardancy (peak heat release rate = 44.5 kW/m2 and heat release rate = 0.8 MJ/m2) due to the physical barrier effect and catalytic carbonization effect of ILC-armored BNNS. Meanwhile, IBAP aerogel films exhibit good flexibility and mechanical properties, even in harsh environments such as acids and bases. Further, IBAP aerogel films can also be used as a substrate for paraffin phase change composites. The ILC-armored BNNS provides a practical way to produce flame-resistant polymer composites with high thermal conductivity for TIMs in modern electronic devices.

12.
Insights Imaging ; 14(1): 52, 2023 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-36977913

RESUMEN

OBJECTIVE: To build a clinical-radiomics model based on noncontrast computed tomography images to identify the risk of hemorrhagic transformation (HT) in patients with acute ischemic stroke (AIS) following intravenous thrombolysis (IVT). MATERIALS AND METHODS: A total of 517 consecutive patients with AIS were screened for inclusion. Datasets from six hospitals were randomly divided into a training cohort and an internal cohort with an 8:2 ratio. The dataset of the seventh hospital was used for an independent external verification. The best dimensionality reduction method to choose features and the best machine learning (ML) algorithm to develop a model were selected. Then, the clinical, radiomics and clinical-radiomics models were developed. Finally, the performance of the models was measured using the area under the receiver operating characteristic curve (AUC). RESULTS: Of 517 from seven hospitals, 249 (48%) had HT. The best method for choosing features was recursive feature elimination, and the best ML algorithm to build models was extreme gradient boosting. In distinguishing patients with HT, the AUC of the clinical model was 0.898 (95% CI 0.873-0.921) in the internal validation cohort, and 0.911 (95% CI 0.891-0.928) in the external validation cohort; the AUC of radiomics model was 0.922 (95% CI 0.896-0.941) and 0.883 (95% CI 0.851-0.902), while the AUC of clinical-radiomics model was 0.950 (95% CI 0.925-0.967) and 0.942 (95% CI 0.927-0.958) respectively. CONCLUSION: The proposed clinical-radiomics model is a dependable approach that could provide risk assessment of HT for patients who receive IVT after stroke.

13.
Langmuir ; 39(10): 3589-3600, 2023 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-36848873

RESUMEN

Nitrogen-doped lubricating additives have been proved to be an effective strategy to improve the tribological properties of lubricating oil. However, the traditional preparation methods of nitrogen-doped lubricating additives have the defects including harsh preparation conditions and a time-consuming preparation process. Herein, we report a preparation method of nitrogen-doped carbon dot (NCD) lubricating additives in a short time by one-step aldehyde condensation reaction at room temperature. The small size effect and nitrogen-containing functional groups of NCD lubricating additives provide favorable conditions for their dispersion and low friction in base oil. The tribological properties of NCD lubricating additives in sunflower oil (SFO) and PAO10 were systematically evaluated. The results show that NCD lubricating additives could reduce the average friction coefficient of SFO from 0.15 to 0.06 and PAO10 oil from 0.12 to 0.06, and the wear width is also decreased by 50-60%. In particular, the friction curve is very stable, and the friction coefficient was maintained at about 0.06 even under the working time of 5 h. By analyzing the morphology and chemical properties of the worn surface, the lubrication effect of NCDs is attributed to its small size effect and adsorption, which was easy to enter the friction gap to fill and repair. Furthermore, the doping of nitrogen induces the occurrence of friction chemical reactions, forming a friction film of nitrides and metal oxides at the friction interface, which effectively reduces the friction and wear of the surface. These findings provide a possibility for the convenient and effective preparation of NCD lubricating additives.

14.
ACS Appl Mater Interfaces ; 15(8): 11053-11061, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36791287

RESUMEN

Recently, smart windows have attracted widespread attention on account of their unique features, yet traditional smart windows still rely on external energy support to accomplish dynamic reversible switching, which not only confines usage but also causes waste of energy. For this purpose, we have prepared hemiaminal dynamic covalent network (HDCN) film with outstanding flexibility and strength by a simple and low-cost method, in which the modulus is 206.28 MPa and the elongation at break is 39.02%. Additionally, the transition from a transparent to an opaque state is achieved when the film is stimulated by humidity, and the dynamic transformation of the film to different phases of transparency is obtained when the film is exposed to different relative humidities (60-99%). Most importantly, HDCN film fulfills the modern green requirements and enables complete dissolution in a certain mildly acidic solution, avoiding environmental pollution when the material is discarded due to loss of function. The dynamic tunability of HDCN film demonstrates great advantages and potential in smart windows and anticounterfeiting.

15.
J Pers Med ; 12(12)2022 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-36556272

RESUMEN

Hemorrhagic complication (HC) is the most severe complication of intravenous thrombolysis (IVT) in patients with acute ischemic stroke (AIS). This study aimed to build a machine learning (ML) prediction model and an application system for a personalized analysis of the risk of HC in patients undergoing IVT therapy. We included patients from Chongqing, Hainan and other centers, including Computed Tomography (CT) images, demographics, and other data, before the occurrence of HC. After feature engineering, a better feature subset was obtained, which was used to build a machine learning (ML) prediction model (Logistic Regression (LR), Random Forest (RF), Support Vector Machine (SVM), eXtreme Gradient Boosting (XGB)), and then evaluated with relevant indicators. Finally, a prediction model with better performance was obtained. Based on this, an application system was built using the Flask framework. A total of 517 patients were included, of which 332 were in the training cohort, 83 were in the internal validation cohort, and 102 were in the external validation cohort. After evaluation, the performance of the XGB model is better, with an AUC of 0.9454 and ACC of 0.8554 on the internal validation cohort, and 0.9142 and ACC of 0.8431 on the external validation cohort. A total of 18 features were used to construct the model, including hemoglobin and fasting blood sugar. Furthermore, the validity of the model is demonstrated through decision curves. Subsequently, a system prototype is developed to verify the test prediction effect. The clinical decision support system (CDSS) embedded with the XGB model based on clinical data and image features can better carry out personalized analysis of the risk of HC in intravenous injection patients.

16.
ACS Nano ; 16(10): 17049-17061, 2022 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-36173441

RESUMEN

Three-dimensional (3D) elastic aerogels enable diverse applications but are usually restricted by their low thermal and electrical transfer efficiency. Here, we demonstrate a strategy for fabricating the highly thermally and electrically conductive aerogels using hybrid carbon/ceramic structural units made of hexagonal boron nitride nanoribbons (BNNRs) with in situ-grown orthogonally structured graphene (OSG). High-aspect-ratio BNNRs are first interconnected into a 3D elastic and thermally conductive skeleton, in which the horizontal graphene layers of OSG provide additional hyperchannels for electron and phonon conduction, and the vertical graphene sheets of OSG greatly improve surface roughness and charge polarization ability of the entire skeleton. The resulting OSG/BNNR hybrid aerogel exhibits very high thermal and electrical conductivity (up to 7.84 W m-1 K-1 and 340 S m-1, respectively) at a low density of 45.8 mg cm-3, which should prove to be vastly advantageous as compared to the reported carbonic and/or ceramic aerogels. Moreover, the hybrid aerogel possesses integrated properties of wide temperature-invariant superelasticity (from -196 to 600 °C), low-voltage-driven Joule heating (up to 42-134 °C at 1-4 V), strong hydrophobicity (contact angel of up to 156.1°), and powerful broadband electromagnetic interference (EMI) shielding effectiveness (reaching 70.9 dB at 2 mm thickness), all of which can maintain very well under repeated mechanical deformations and long-term immersion in strong acid or alkali solution. Using these extraordinary comprehensive properties, we prove the great potential of OSG/BNNR hybrid aerogel in wearable electronics for regulating body temperature, proofing water and pollution, removing ice, and protecting human health against EMI.

17.
ACS Appl Mater Interfaces ; 14(25): 29302-29314, 2022 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-35707960

RESUMEN

Solar energy-facilitated materials are promising to solve energy problems by converting clean solar energy to thermal energy. However, heat loss of photothermal materials still limits the photothermal conversion phenomenon. Herein, we designed bio-inspired hollow carbon microtubes (HCMTs) by one-step carbonization of renewable cotton fibers, which can avoid the complex preparation procedures of the template method. Similar to polar bears, the hollow construction can efficiently reduce heat loss, which improves the utilization of light and photothermal property. The HCMTs can be applied on a variety of substrates to obtain multifunctional photothermal protective coatings. The temperature of the coating can rapidly warm up to 97.7 °C under 1 kW/m2 sun irradiation. In addition, the coatings show excellent superhydrophobic property (CA of 161.5 ± 0.9°), which can prevent the adhesion of the contaminant and maintain the long-time photothermal property of the surface. Also, the coating is able to withstand sandpaper abrasion, repeat tape-peeling, and tribological friction without losing superhydrophobic properties, indicating remarkable mechanical stability. Furthermore, the coating can withstand high-temperature calcination (400 °C), long-time UV radiation, and corrosive liquid erosion, which exhibits prominent chemical stability. More importantly, the combination of active deicing and passive anti-icing of the coating can effectively prevent the formation and accumulation of ice on the surface. The outstanding environmental adaptability can greatly extend its lifespan and meet the long-term service conditions.

18.
Langmuir ; 38(25): 7791-7801, 2022 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-35687508

RESUMEN

Because of the high synthesis cost, strong chemical inertness, complex process, and easy to endanger environment of traditional carbon-based nanolubricant additives, the development of its application in lubrication is limited. Therefore, a new type of lubricant additive with low cost, high yield, high performance, and environmental protection is urgently needed. Herein, a kilogram-scale carbon dots (CDs) lubricant additive was prepared by a simple and green one-step reaction of aldol condensation, which showed excellent lubricating properties in water and sunflower oil. The tribological properties of the CDs lubricant additive at different concentrations, loads, and speeds were systematically studied. The results show that the average friction coefficient of water is significantly reduced by 75% by a CDs lubricant additive. In particular, CDs not only exhibited excellent service life and lubrication stability during friction but also kept the friction coefficient change rate of sunflower seed oil close to 0 within 500 min. According to the tribological evaluation and wear surface analysis, the lubrication mechanism of CDs was attributed to their own morphological characteristics and abundant oxygen-containing functional groups on the surface. In the friction process, the charge adsorption effect, the adsorption protective film, and the hydrogen bonding layer are generated, which play an essential role in obvious antiwear and friction reduction. Therefore, this work provides a reference for the preparation of high-performance and high-yield lubricant additives.

19.
Front Psychol ; 13: 1049174, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36698585

RESUMEN

As competition grows, when employees are required to accelerate innovation, they also face increasing time pressure. In order to shed light on how time pressure affects employees' innovation performance, two studies were conducted to examine the effect of time pressure on innovation performance. In Study 1, based on 50 effect sizes from 50 independent samples (N = 15,751) in 40 articles, a meta-analysis was conducted to examine the J-shaped effect of time pressure on innovation performance. In Study 2, based on a two-wave survey of 645 employees, the mechanism underlying the J-shaped effect of time pressure on innovation performance was explored. Results from Study 1 revealed that time pressure had a J-shaped effect on innovation performance, such that high levels of time pressure had a more positive effect on innovation performance. Results from Study 2 showed that learning behavior significantly mediated the J-shaped effect of time pressure on innovation performance, and that supervisor developmental feedback moderated the intermediary process. These results deepen the understanding of the relationship between time pressure and innovation performance, and provide practical advice on how to manage innovation performance under time pressure.

20.
Carbohydr Polym ; 272: 118527, 2021 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-34420761

RESUMEN

Design and fabrication of structurally optimized three-dimensional porous materials are highly desirable for engineering applications. Herein, through a facile bidirectional freezing technique, we prepared superelastic biomass sponges in air and underwater, which possess biomimetic porous sandwich-like architectures with lamellar layers interconnected by porous microstructures, similar to the structure of rice stems. This distinctive architecture was obtained by incorporating Typha orientalis fibers (TOFs) and graphene oxide (GO) nanosheets into sodium alginate (SA) matrix, in which SA flakes and GO nanosheets were intimately grown along TOFs. The porous sandwich-like microstructure allows stress to be distributed throughout the lamellar to avoid stress concentration and endows SA/TOFs/GO sponge with excellent mechanical compressibility and recoverability. Especially, underwater superelasticity and superoleophobicity of the sponge facilitates removal of water-miscible contaminants or oil/water separation with high efficiency. This novel strategy for the design biomimetic architecture of superelastic biomass sponge can promote its application for protecting environment.


Asunto(s)
Alginatos , Biomimética , Grafito , Porosidad
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