Showing papers by "Yu Huang published in 2017"
TL;DR: In this article, a three-dimensional (3D) holey-graphene/niobia (Nb2O5) composite for ultra-high-rate energy storage at high mass loading was proposed.
Abstract: Nanostructured materials have shown extraordinary promise for electrochemical energy storage but are usually limited to electrodes with rather low mass loading (~1 milligram per square centimeter) because of the increasing ion diffusion limitations in thicker electrodes. We report the design of a three-dimensional (3D) holey-graphene/niobia (Nb2O5) composite for ultrahigh-rate energy storage at practical levels of mass loading (>10 milligrams per square centimeter). The highly interconnected graphene network in the 3D architecture provides excellent electron transport properties, and its hierarchical porous structure facilitates rapid ion transport. By systematically tailoring the porosity in the holey graphene backbone, charge transport in the composite architecture is optimized to deliver high areal capacity and high-rate capability at high mass loading, which represents a critical step forward toward practical applications.
1,099 citations
TL;DR: Density functional theory calculations reveal that the improved activity and stability stems from the promoted production of free OH radicals (on Ni active sites) which facilitate the oxidative removal of carbonaceous poison and combination with CH3CO radicals on adjacent Pd active sites.
Abstract: Incorporating oxophilic metals into noble metal-based catalysts represents an emerging strategy to improve the catalytic performance of electrocatalysts in fuel cells. However, effects of the distance between the noble metal and oxophilic metal active sites on the catalytic performance have rarely been investigated. Herein, we report on ultrasmall (∼5 nm) Pd–Ni–P ternary nanoparticles for ethanol electrooxidation. The activity is improved up to 4.95 A per mgPd, which is 6.88 times higher than commercial Pd/C (0.72 A per mgPd), by shortening the distance between Pd and Ni active sites, achieved through shape transformation from Pd/Ni–P heterodimers into Pd–Ni–P nanoparticles and tuning the Ni/Pd atomic ratio to 1:1. Density functional theory calculations reveal that the improved activity and stability stems from the promoted production of free OH radicals (on Ni active sites) which facilitate the oxidative removal of carbonaceous poison and combination with CH3CO radicals on adjacent Pd active sites. Incorporating oxophilic metals into noble metal catalysts can improve electrocatalytic performance; however, the influence of the distance between noble metal and oxophilic metal active site is not well understood. Here the authors make Pd–Ni–P nanocatalysts for ethanol oxidation, with improved performance achieved by shortening the Pd–Ni distance.
354 citations
TL;DR: The results of this study indicate that CQDs/ZnFe2O4 is a promising photocatalyst for air purification.
Abstract: A highly efficient and environmentally-friendly oxidation process is always desirable for air purification. This study reported a novel carbon quantum dots (CQDs)/ZnFe2O4 composite photocatalyst for the first time through a facile hydrothermal process. The CQDs/ZnFe2O4 (15 vol %) composite demonstrates stronger transient photocurrent response, approximately 8 times higher than that of ZnFe2O4, indicating superior transfer efficiency of photogenerated electrons and separation efficiency of photogenerated electron–hole pairs. Compared with pristine ZnFe2O4 nanoparticles, CQDs/ZnFe2O4 displayed enhanced photocatalytic activities on gaseous NOx removal and high selectivity for nitrate formation under visible light (λ > 420 nm) irradiation. Electron spin resonance analysis and a series of radical-trapping experiments showed that the reactive species contributing to NO elimination were ·O2– and ·OH radicals. The possible mechanisms were proposed regarding how CQDs improve the photocatalytic performance of ZnFe2...
241 citations
TL;DR: This catalyst was designed on the basis of the following three points: ultrathin NWs with high numbers of surface atoms can increase the atomic efficiency of Pt and thus decrease the catalyst cost, and the incorporation of Mo can stabilize both Ni and Pt atoms, leading to high catalytic stability.
Abstract: Developing cost-effective, active, and durable electrocatalysts is one of the most important issues for the commercialization of fuel cells. Ultrathin Pt-Mo-Ni nanowires (NWs) with a diameter of ~2.5 nm and lengths of up to several micrometers were synthesized via a H2-assisted solution route (HASR). This catalyst was designed on the basis of the following three points: (i) ultrathin NWs with high numbers of surface atoms can increase the atomic efficiency of Pt and thus decrease the catalyst cost; (ii) the incorporation of Ni can isolate Pt atoms on the surface and produce surface defects, leading to high catalytic activity (the unique structure and superior activity were confirmed by spherical aberration-corrected electron microscopy measurements and ethanol oxidation tests, respectively); and (iii) the incorporation of Mo can stabilize both Ni and Pt atoms, leading to high catalytic stability, which was confirmed by experiments and density functional theory calculations. Furthermore, the developed HASR strategy can be extended to synthesize a series of Pt-Mo-M (M = Fe, Co, Mn, Ru, etc.) NWs. These multimetallic NWs would open up new opportunities for practical fuel cell applications.
217 citations
TL;DR: A novel approach to synthesize atomically dispersed uniform clusters via a cage-separated precursor preselection and pyrolysis strategy is reported, finding that Ru3/CN exhibits excellent catalytic activity, high chemoselectivity, and significantly high turnover frequency for oxidation of 2-aminobenzyl alcohol.
Abstract: Here we report a novel approach to synthesize atomically dispersed uniform clusters via a cage-separated precursor preselection and pyrolysis strategy. To illustrate this strategy, well-defined Ru3(CO)12 was separated as a precursor by suitable molecular-scale cages of zeolitic imidazolate frameworks (ZIFs). After thermal treatment under confinement in the cages, uniform Ru3 clusters stabilized by nitrogen species (Ru3/CN) were obtained. Importantly, we found that Ru3/CN exhibits excellent catalytic activity (100% conversion), high chemoselectivity (100% for 2-aminobenzaldehyde), and significantly high turnover frequency (TOF) for oxidation of 2-aminobenzyl alcohol. The TOF of Ru3/CN (4320 h–1) is about 23 times higher than that of small-sized (ca. 2.5 nm) Ru particles (TOF = 184 h–1). This striking difference is attributed to a disparity in the interaction between Ru species and adsorbed reactants.
214 citations
TL;DR: In this article, the degradation pathway of methylammonium lead iodide microplates was investigated using in situ transmission electron microscopy to follow the thermal degradation process, and it was shown that under moderate heating at 85°C the crystalline structure shows a gradual evolution from tetragonal MAPbI3 to trigonal lead iodides layered with a fixed crystallographic direction.
194 citations
TL;DR: A switchable cross-species liquid-repellent surface is developed that can rapidly switch between two distinct liquid- repellent modes: i) the superhydrophobic mode, modeled after lotus leaves, and ii) the slippery mode, modeling after the pitcher-plant peristome.
Abstract: A switchable cross-species liquid-repellent surface is developed that can rapidly switch between two distinct liquid-repellent modes: i) the superhydrophobic mode, modeled after lotus leaves, and ii) the slippery mode, modeled after the pitcher-plant peristome. Adaptive liquid repellency and programmable fog harvesting are demonstrated as application examples for the new switchable surface.
185 citations
TL;DR: In this paper, perovskite LaFeO 3 microspheres were synthesized and employed as photocatalysts to remove parts-per-billion level NO, and it was found that the photocatalyst efficiency was dramatically improved by coupling with SrTiO 3 nanocubes.
Abstract: Perovskite oxides (ABO 3 ) are widely studied as excellent sorbing and catalytic materials for NO x abatement in automobile or stationary depollution processes, and recently they have attracted significant interest in solar conversion reactions due to the flexible composition, facile optical and electronic tuning properties. In this work, perovskite LaFeO 3 microspheres were synthesized and employed as photocatalysts to remove parts-per-billion level NO, and it is found that the photocatalytic efficiency was dramatically improved by coupling with SrTiO 3 nanocubes. The LaFeO 3 -SrTiO 3 composite with proper mass ratio (0.3–1) displayed 3.1 and 4.5 fold enhancement in NO removal rate as compared to the pristine LaFeO 3 and SrTiO 3 , respectively. Moreover, the LaFeO 3 -SrTiO 3 composite exhibited decreased NO 2 yield possibly due to the basic surface property of strontium sites. The synergistically improved activity was due to broad visible light harvest, enlarged surface area, and most importantly, the depressed surface charge recombination originating from the perfectly matched LaFeO 3 -SrTiO 3 interface and facile charge transfer along the staggered band alignment. The temperature programmed desorption (TPD) analysis revealed that the composite had efficient chemisorption for NO. Further, the electron spin resonance (ESR) combined with the radical scavenger tests and density functional theory (DFT) calculations suggested that the photocatalytic NO oxidation via superoxide radicals ( O 2 − ) from SrTiO 3 and direct hole (h + ) transfer from LaFeO 3 might be the predominant routes. We believe that this study provides some new insights into perovskite nanomaterials as photocatalyst for NO x abatement under ambient conditions.
127 citations
TL;DR: In this article, a first comprehensive campaign was conducted at an urban roadside in Xi'an, China in summer 2016, and a total of 57 VOCs, as known as critical surface ozone (O3) precursors, and other trace gases were measured simultaneously during the sampling period.
116 citations
TL;DR: In this article, a counter-pumped all-optical difference frequency process was proposed to coherently generate and control THz plasmons in atomic layer graphene with an octave tunability and high efficiency.
Abstract: Graphene, a unique two-dimensional material of carbon in a honeycomb lattice, has brought remarkable breakthroughs across the domains of electronics, mechanics, and thermal transport, driven by the quasiparticle Dirac fermions obeying a linear dispersion. Here we demonstrate a counter-pumped all-optical difference frequency process to coherently generate and control THz plasmons in atomic layer graphene with an octave tunability and high efficiency. We leverage the inherent surface asymmetry of graphene for a strong second-order nonlinear polarizability chi(2), which together with tight plasmon field confinement, enables a robust difference frequency signal at THz frequencies. The counter-pumped resonant process on graphene uniquely achieves both energy and momentum conservation. Consequently we demonstrate a dual-layer graphene heterostructure that achieves the charge- and gate-tunability of the THz plasmons over an octave, from 9.4 THz to 4.7 THz, bounded only by the pump amplifier optical bandwidth. Theoretical modeling supports our single-volt-level gate tuning and optical-bandwidth-bounded 4.7 THz phase-matching measurements, through the random phase approximation with phonon coupling, saturable absorption, and below the Landau damping, to predict and understand the graphene carrier plasmon physics.
114 citations
TL;DR: The chemical composition of PM2.5 and cellular effects from exposure to fine aerosol extracts were studied for samples collected in Beijing, Tianjin, Shijiazhuang, and Hengshui, China in winter 2015 and provides a new approach for evaluating relationships between air-quality and cell toxicity with respect to specific chemicals.
TL;DR: In this article, on-site measurements of straw smoldering in a residence with a Chinese ‘Heated Kang’ (Scenario 1) were done to determine the emissions factors (EFs) for pollutants.
TL;DR: The fabrication and optical characterization of a biologically inspired antireflective surface that emulates the surface architecture of the leafhopper-produced brochosomes with antire flective performance comparable to the state-of-the-art antireFlective coatings is reported.
Abstract: Since the early discovery of the antireflection properties of insect compound eyes, new examples of natural antireflective coatings have been rare. Here, we report the fabrication and optical characterization of a biologically inspired antireflective surface that emulates the intricate surface architectures of leafhopper-produced brochosomes—soccer ball-like microscale granules with nanoscale indentations. Our method utilizes double-layer colloidal crystal templates in conjunction with site-specific electrochemical growth to create these structures, and is compatible with various materials including metals, metal oxides, and conductive polymers. These brochosome coatings (BCs) can be designed to exhibit strong omnidirectional antireflective performance of wavelengths from 250 to 2000 nm, comparable to the state-of-the-art antireflective coatings. Our results provide evidence for the use of brochosomes as a camouflage coating against predators of leafhoppers or their eggs. The discovery of the antireflective function of BCs may find applications in solar energy harvesting, imaging, and sensing devices. New examples of natural antireflective coatings are rare. Here, Yang et al. report the fabrication and optical characterization of a biologically inspired antireflective surface that emulates the surface architecture of the leafhopper-produced brochosomes with antireflective performance from 250 to 2000 nm.
TL;DR: The study demonstrates a low-cost and scalable pathway to high-performance flexible thin film thermoelectric devices from relatively earth-abundant elements, with negligible performance change after 1000 bending cycles.
Abstract: A solid-state thermoelectric device is attractive for diverse technological areas such as cooling, power generation and waste heat recovery with unique advantages of quiet operation, zero hazardous emissions, and long lifetime. With the rapid growth of flexible electronics and miniature sensors, the low-cost flexible thermoelectric energy harvester is highly desired as a potential power supply. Herein, a flexible thermoelectric copper selenide (Cu2 Se) thin film, consisting of earth-abundant elements, is reported. The thin film is fabricated by a low-cost and scalable spin coating process using ink solution with a truly soluble precursor. The Cu2 Se thin film exhibits a power factor of 0.62 mW/(m K2 ) at 684 K on rigid Al2 O3 substrate and 0.46 mW/(m K2 ) at 664 K on flexible polyimide substrate, which is much higher than the values obtained from other solution processed Cu2 Se thin films (<0.1 mW/(m K2 )) and among the highest values reported in all flexible thermoelectric films to date (≈0.5 mW/(m K2 )). Additionally, the fabricated thin film shows great promise to be integrated with the flexible electronic devices, with negligible performance change after 1000 bending cycles. Together, the study demonstrates a low-cost and scalable pathway to high-performance flexible thin film thermoelectric devices from relatively earth-abundant elements.
TL;DR: The photoluminescence spectra essentially maintain the same features before and after the thermal annealing process, demonstrating that the charge transport measurement provides a sensitive way to probe low-concentration defects in perovskite materials.
Abstract: Transformation of unipolar n-type semiconductor behavior to ambipolar and finally to unipolar p-type behavior in CH3 NH3 PbI3 microplate field-effect transistors by thermal annealing is reported. The photoluminescence spectra essentially maintain the same features before and after the thermal annealing process, demonstrating that the charge transport measurement provides a sensitive way to probe low-concentration defects in perovskite materials.
TL;DR: In this paper, the pomegranate-like structure of the Bi-CN composites and an explanation for their improved photocatalytic activity were proposed. But they did not provide new insights into the mechanistic understanding of g-C3N4-based photocatalysis.
TL;DR: In this paper, a review on the photodetection in the infrared spectrum and recent progresses in constructing advanced infrared photodetsectors based on quantum wells, dots, and the rapidly evolving 1D and 2D materials are summarized.
Abstract: Infrared photodetectors are finding widespread applications in telecommunication, motion detection, chemical sensing, thermal imaging and bio-medical imaging, etc. The nanostructured materials and architectures are attracting extensive interests in photodetectors in view of the potential benefits from confined light-matter interaction, fast carrier dynamics and ultrahigh photoconductive gains. This review concentrates on the photodetection in the infrared spectrum and recent progresses in constructing advanced infrared photodetectors based on quantum wells, dots, and the rapidly evolving 1D and 2D materials are summarized. The recent achievements in exploring nanostructured plasmonic metamaterials for the intriguing subwavelength photon confinement and waveguides in devices are also surveyed considering their importance in device integration. An outlook of infrared photodetection is given in the end as a guideline for this vigorous field.
TL;DR: In this article, the authors measured optical and chemical properties of PM2.5 brown carbon (BrC) in Xi'an, China during two and a half months from 2 November 2009 to 13 October 2010.
TL;DR: It is shown that PPARδ is a crucial mediator for exercise to exert a beneficial effect on the vascular endothelium in diabetic mice and provides potentially effective targets for treating diabetic vasculopathy.
Abstract: Physical activity has profound benefits on health, especially on cardiometabolic wellness. Experiments in rodents with trained exercise have shown that exercise improves vascular function and reduces vascular inflammation by modulating the balance between nitric oxide (NO) and oxidative stress. However, the upstream regulator of exercise-induced vascular benefits is unclear. We aimed to investigate the involvement of peroxisome proliferator-activated receptor δ (PPARδ) in exercise-induced vascular functional improvement. We show that PPARδ is a crucial mediator for exercise to exert a beneficial effect on the vascular endothelium in diabetic mice. In db/db mice and high-fat diet-induced obese mice, 4 weeks of treadmill exercise restored endothelium-dependent vasodilation of aortas and flow-mediated vasodilation in mesenteric resistance arteries, whereas genetic ablation of Ppard abolished such improvements. Exercise induces AMPK activation and subsequent PPARδ activation, which help to reduce endoplasmic reticulum (ER) and oxidative stress, thus increasing NO bioavailability in endothelial cells and vascular tissues. Chemical chaperones 4-phenylbutyric acid and tauroursodeoxycholic acid decrease ER stress and protect against endothelial dysfunction in diabetic mice. The results demonstrate that PPARδ-mediated inhibition of ER stress contributes to the vascular benefits of exercise and provides potentially effective targets for treating diabetic vasculopathy.
TL;DR: In this article, a core-shell-structured Bi2O3 nanospheres were synthesized through a one-step solvothermal method, and the reaction mechanisms on NO removal were proposed.
Abstract: The size, morphology, and structure of a Bi nanoparticle can significantly affect its photocatalytic performance. In this study, core–shell structured Bi@amorphous Bi2O3 nanospheres were synthesized through a one-step solvothermal method, and the reaction mechanisms on NO removal were proposed. It was found that Bi nanoparticles can generate charge carriers by surface plasma resonance (SPR) under visible light irradiation, while the surface amorphous Bi2O3 layer can facilitate the charge carriers’ separation. The Bi@Bi2O3 sample with the synthesis time of 18 h exhibited superior visible light photocatalytic activity for NO degradation, attributed to the suited size and suitable amorphous Bi2O3 layer. •O2–, 1O2, and •OH radicals were identified as the main reactive species involved in the photocatalysis processes. Moreover, the enhancement mechanisms of photocatalytic NO removal over Bi@Bi2O3 samples were discussed. This study demonstrated that the fabrication of core–shell structured Bi@Bi2O3 is a good st...
TL;DR: It is demonstrated that Bmal1 deficiency in macrophages promotes atherosclerosis by enhancing recruitment of Ly6chi monocytes to atherosclerotic lesions.
Abstract: BMAL1, the nonredundant transcription factor in the core molecular clock, has been implicated in cardiometabolic diseases in mice and humans. BMAL1 controls the cyclic trafficking of Ly6chi monocytes to sites of acute inflammation. Myeloid deficiency of Bmal1 also worsens chronic inflammation in diet-induced obesity. We studied whether myeloid Bmal1 deletion promotes atherosclerosis by enhancing monocyte recruitment to atherosclerotic lesions. By generating Bmal1FloxP/FloxP;LysMCre mice on the Apoe-/- background, we showed that Bmal1 deletion in myeloid cells increased the size of atherosclerotic lesions. Bmal1 deficiency in monocytes and macrophages resulted in an increased total number of lesional macrophages in general and Ly6chi infiltrating monocyte-macrophages in particular, accompanied by skewed M2 to M1 macrophage phenotype. Ly6chi and/or Ly6clo monocyte subsets in blood, spleen, and bone marrow were not altered. Cell tracking and adoptive transfer of Ly6chi monocytes showed Bmal1 deficiency induced more trafficking of Ly6chi monocytes to atherosclerotic lesions, preferential differentiation of Ly6chi monocytes into M1 macrophages, and increased macrophage content and lesion size in the carotid arteries. We demonstrated that Bmal1 deficiency in macrophages promotes atherosclerosis by enhancing recruitment of Ly6chi monocytes to atherosclerotic lesions.-Huo, M., Huang, Y., Qu, D., Zhang, H., Wong, W. T., Chawla, A., Huang, Y., Tian, X. Y. Myeloid Bmal1 deletion increases monocyte recruitment and worsens atherosclerosis.
TL;DR: Hybrid laser-magnetic welding 316L steel with butt joint was investigated in this paper, where the bottom width of the bead profile was broadened from 1.606mm to 2.492mm, grain size was homogenized, and austenitic content was also improved.
TL;DR: In this paper, titania/hydroxyapatite (TiO2/HAp) composites were synthesized by a facile hydrothermal method and employed to decontaminate nitric oxide (NO) in air under simulated solar light irradiation.
Abstract: Effective photocatalysis processes with production of fewer toxic intermediates are highly desirable for air purification. In this study, titania/hydroxyapatite (TiO2/HAp) composites were synthesized by a facile hydrothermal method and employed to decontaminate nitric oxide (NO) in air under simulated solar light irradiation for the first time. It was found that the photocatalytic activity of the as-prepared TiO2/HAp composite (44.61%) was superior to those of the pristine components (TiO2: 38.57%, HAp: 36.73%) and mechanically mixed samples (35.36%). The TiO2/HAp composite with mass ratio of 3 : 1 (75% TiO2/HAp) exhibited the highest NO removal efficiency among them. Moreover, the toxic intermediate NO2 production was significantly inhibited over TiO2/HAp. These synergistically improved properties can be ascribed to the high separation efficiency and faster transfer of the photo-generated charge carriers as evidenced by the experimental results from photocurrent tests and electrochemical impedance spectroscopy (EIS). The results from temperature programmed desorption (TPD) confirmed that the 75% TiO2/HAp sample had stronger chemisorption for NO due to the increased concentration of surface OH groups. Furthermore, the electron spin resonance (ESR) characterization suggested that ˙O2− and ˙OH radicals were the major species involved for NO removal over TiO2/HAp composites. The five recycling tests suggested that the TiO2/HAp has superior photocatalytic stability. This study suggests that the combination of TiO2 with HAp is an effective approach for air purification.
TL;DR: Result of source apportionment indicated that industrial emission, vehicular exhaust, and solvent evaporation were three major pollution origins, suggesting the strong influences from industrial and traffic sectors.
Abstract: Level of surface ozone (O3) has been increasing continuously in China in recent years, while its contributors and formation pathways are less understood. In this study, distributions of volatile organic compounds (VOCs) and the roles on O3 pollution have been investigated in a typical industrial city of Baoji in Northwestern China by means of monitoring of their concentrations and other trace gases. The air samples have been collected at three sites according to urban function area. Concentration of VOCs in Weibin site, which near to industrial zone, was higher than most of other cities in China, and the ambient VOCs were dominated by aromatics and alkenes. The temporal variations of VOCs and O3 coincided with the surface wind, implying that the formation of O3 was impacted by both exports of plumes upwind and local photochemical reactions. Result of source apportionment indicated that industrial emission, vehicular exhaust, and solvent evaporation were three major pollution origins. Alkenes and aromatics contributed to the largest fractions of photochemical reactivity, suggesting the strong influences from industrial and traffic sectors. The study presents the characteristic VOCs and other factors in the contribution of O3 formation in China.
TL;DR: It is shown that tendon sheath cells harbor stem/progenitor cell properties and contribute to tendon repair by activating Hedgehog signaling, and it is found that Osteocalcin (Bglap) can be used as an adult tendon-sheath-specific marker in mice.
Abstract: Both extrinsic and intrinsic tissues contribute to tendon repair, but the origin and molecular functions of extrinsic tissues in tendon repair are not fully understood. Here we show that tendon sheath cells harbor stem/progenitor cell properties and contribute to tendon repair by activating Hedgehog signaling. We found that Osteocalcin (Bglap) can be used as an adult tendon-sheath-specific marker in mice. Lineage tracing experiments show that Bglap-expressing cells in adult sheath tissues possess clonogenic and multipotent properties comparable to those of stem/progenitor cells isolated from tendon fibers. Transplantation of sheath tissues improves tendon repair. Mechanistically, Hh signaling in sheath tissues is necessary and sufficient to promote the proliferation of Mkx-expressing cells in sheath tissues, and its action is mediated through TGFβ/Smad3 signaling. Furthermore, co-localization of GLI1+ and MKX+ cells is also found in human tendinopathy specimens. Our work reveals the molecular function of Hh signaling in extrinsic sheath tissues for tendon repair.
TL;DR: In this article, a facile ultrasonic spray pyrolysis (USP) method using NaCl as a salt template was used to synthesize hollow Bi2WO6 microspheres.
TL;DR: A novel fluorescent detection strategy based on DNAzyme branched junction structure with three kinds of DNAzymes and graphene oxide that was successfully used for simultaneous detection of Cu2+, Mg2+ and Pb2+ in human serum and had potential application for simultaneous Detection of multiple metal ions in environmental and biological samples.
TL;DR: Wang et al. as mentioned in this paper investigated the relationship between indoor pollution levels and ventilation time and found that the concentrations of formaldehyde and TVOC decreased with ventilation time, and the duration was one year after decoration especially after summer ventilation.
Abstract: To investigate the indoor air quality (IAQ) over Xi’an, the concentrations of volatile organic compounds (VOCs, including formaldehyde, benzene, toluene, o-xylene, p-xylene, n-butyl acetate, ethylbenzene, styrene, n-undecane, and total VOCs) in 471 residential rooms and 58 public rooms during 2014-2015 were determined. All the data were measured at a variety of 6-48 months after the decorations of these rooms. The results showed that formaldehyde was the most serious pollutant in almost all the monitored rooms. The concentrations of formaldehyde in residences and public places ranged from 0.02 mg m^(-3) to 0.45 mg m^(-3) and 0.05 mg m^(-3) to 0.32 mg m^(-3), respectively. And the concentration levels in the 83.6% selected residences and 44.8% public places exceeded the Chinese National Indoor Air Quality Standard (GB/T 18883-2002) of formaldehyde value (0.1 mg m^(-3)). However, the TVOC concentrations in most sites were lower than the Chinese National Standard (GB/T 18883-2002) value. In residences, the formaldehyde and TVOC concentrations in bedrooms were slightly higher than those in living rooms and other rooms. The relationships among formaldehyde and TVOC concentrations with indoor temperature, relative humidity (RH), and decorative materials (curtain, wall decoration, wood floor, and panel furniture) were also investigated. Formaldehyde levels showed strong positive correlation with indoor temperature and RH. However, the TVOC levels had a relatively weak correlation with indoor air temperature and RH. The wall decoration and panel furniture were the main sources of indoor formaldehyde, while wood floor and panel furniture were the main sources of TVOC. In addition, indoor air pollution of three selected newly decorated houses with 11 rooms was monitored monthly for one year to evaluate the relationship between indoor pollution levels and ventilation time. It was found that the concentrations of formaldehyde and TVOC decreased with ventilation time, and the duration was one year after decoration especially after summer ventilation.
TL;DR: In this review, an overview of the fabrications and applications of NPs patterned assembly by printing methods, including inkjet printing, lithography, imprinting, and extended printing techniques is presented.
Abstract: With facile manufacturability and modifiability, impressive nanoparticles (NPs) assembly applications were performed for functional patterned devices, which have attracted booming research attention due to their increasing applications in high-performance optical/electrical devices for sensing, electronics, displays, and catalysis. By virtue of easy and direct fabrication to desired patterns, high throughput, and low cost, NPs assembly printing is one of the most promising candidates for the manufacturing of functional micro-chips. In this review, an overview of the fabrications and applications of NPs patterned assembly by printing methods, including inkjet printing, lithography, imprinting, and extended printing techniques is presented. The assembly processes and mechanisms on various substrates with distinct wettabilities are deeply discussed and summarized. Via manipulating the droplet three phase contact line (TCL) pinning or slipping, the NPs contracted in ink are controllably assembled following the TCL, and generate novel functional chips and correlative integrate devices. Finally, the perspective of future developments and challenges is presented and widely exhibited.
TL;DR: Seasonal variation and spatial distribution of PM2.5 bound polycyclic aromatic hydrocarbons were investigated at urban residential, commercial area, university, suburban region, and industry in Xi'an, during summer and winter time at 2013 and it was demonstrated that PAHs in suburban have significant differences with those in urban residential in both seasons.