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1.
Opt Express ; 32(9): 16426-16436, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38859269

RESUMO

Optical scattering measurement is one of the most commonly used methods for non-contact online measurement of film properties in industrial film manufacturing. Terahertz photons have low energy and are non-ionizing when measuring objects, so combining these two methods can enable online nondestructive testing of thin films. In the visible light band, some materials are transparent, and their thickness and material properties cannot be measured. Therefore, a method based on physical consistency modeling and machine learning is proposed in this paper, which realizes the method of obtaining high-precision thin film parameters through single-frequency terahertz wave measurement, and shows good performance. Through the experimental measurement of organic material thin films, it is proved that the proposed method is an effective terahertz online detection technology with high precision and high throughput.

2.
Eur J Clin Microbiol Infect Dis ; 42(1): 87-98, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36409375

RESUMO

The investigation on antibiotic stewardship in neonatal intensive care unit in China is scarce. This study aimed to analyze the effect of a comprehensive 2-year antibiotic stewardship in a level 4 NICU. During this baseline period from October 1st 2017 to October 1st 2019, continuation of empirical antibiotic therapy for ruled-out sepsis courses was beyond 72 h and for pneumonia was more than 7 days. Meropenem or vancomycin was used even if they were not the only bacterial sensitive antibiotics. The intervention period was from October 2nd 2019 to August 23rd 2021. Three areas for quality improvement were targeted in our center: discontinuation of antibiotic use in ruled-out sepsis within 72 h, treatment duration for culture-negative pneumonia less than 7 days, and vancomycin or meropenem was not used unless the cultured bacteria was only susceptible to them. The total antibiotic consumption decreased from 791.1 to 466.3 days of therapy per 1000 patient days from baseline to intervention period. Antibiotics were stopped within 72 h for 47.48% patients with rule-out sepsis and within 7 days for 75.70% patients with pneumonia compared with 11.56% and 37.69% during the baseline period respectively. The prevalence of multi-drug resistance bacteria decreased from 67.20 to 48.90%. The total use rate of meropenem or vancomycin decreased from 7.6 to 1.8%. Our quality improvement approach on antibiotic strategy significantly reduced antibiotic use and prevalence of multi-drug resistance bacteria in our NICU.


Assuntos
Infecções Bacterianas , Sepse , Recém-Nascido , Humanos , Antibacterianos/farmacologia , Vancomicina/uso terapêutico , Unidades de Terapia Intensiva Neonatal , Sepse/microbiologia , Meropeném/uso terapêutico , Infecções Bacterianas/tratamento farmacológico , Farmacorresistência Bacteriana Múltipla
3.
Inorg Chem ; 61(24): 9257-9268, 2022 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-35670559

RESUMO

We report the synthesis and characterization of a series of new open-framework iron fluoride-fluorophosphates based on linear, trinuclear, and tetranuclear chain FeIII building units. KFe2(PO3F)2F3 (I) consists of {Fe2(O3F)2F2}10- zigzag chains interconnected by P(O/F)4 tetrahedra forming a three-dimensional (3D) open framework. K2Fe(PO2.5F1.5)2F2 (II) is built up by {Fe(PO2.5F1.5)2F2}2- chains separated by K+ cation layers. The framework for K3Fe3(PO4)(PO3F)2F5 (III) contains two-dimensional {Fe3O4F4(PO3F)2}2- sheets, which are built from trimeric Fe-octahedra insulated by PO3F tetrahedra. The macroanionic framework of K3Fe4(PO4)2F9 (IV) comprises linear {Fe4O8F9}10- chains consisting of tetranuclear magnetic clusters of [Fe4O8F9]10- formed via corner-sharing fluorine atoms decorated with PO4 groups. The magnetic characterization of three iron fluorophosphates reveals diversified magnetism: S = 5/2 spin chains for I, antiferromagnetically coupled triangular Fe units for III, and coupled tetrahedral S = 5/2 spin chains for IV. IV shows strong geometric frustration thanks to its spin motifs of corner-shared tetrahedral clusters.

4.
Inorg Chem ; 60(16): 12001-12008, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34309359

RESUMO

Two M2(SeO3)F2 fluoro-selenites (M = Mn2+, Ni2+) have been synthesized using optimized hydrothermal reactions. Their 3D framework consists of 1D-[MO2F2]4-chains of edge-sharing octahedra with a rare topology of alternating O-O and F-F µ2 bridges. The interchain corner-sharing connections are assisted by the mixed O vs F anionic nature and develop a complex set of M-X-M superexchanges as calculated by LDA+U. Their interplay induces prominent in-chain antiferromagnetic frustration, while the interchain exchanges are responsible for the cycloidal magnetic structure observed below TN ≈ 21.5 K in the Ni2+ case. For comparison the Mn2+ compound develops a nearly collinear spin (canted) ordering below TN ≈ 26 K with ferromagnetic chain units.

5.
Inorg Chem ; 60(17): 13707-13717, 2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34380318

RESUMO

Three new alkali-metal manganese fluoride selenates, A2Mn(SeO4)F3 (A = K, Rb, Cs), were prepared through hydrothermal redox reactions. The products consisted of one-dimensional polymeric anionic ∞[Mn(SeO4)F3]2- chains, where the A+ cations are connected by O and/or F atoms to form blocks with two-dimensional layers. A2Mn(SeO4)F3 (A= Rb, Cs) is isostructural with the monoclinic space group P21/c, while K2Mn(SeO4)F3 crystallizes in the orthorhombic space group Pbcn. A2Mn(SeO4)F3 (A = K, Rb, Cs) forms spin chains of Mn3+ with different Mn-F-Mn bridges, which showed canting antiferromagnetic behaviors. Single-crystal magnetic measurements revealed that the magnetic moments of the Mn ions were more canted for larger alkali-metal compounds in an antiferromagnetically ordered state.

6.
Inorg Chem ; 59(6): 3794-3804, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32114764

RESUMO

Four transition-metal monofluorophosphates, with a chemical formula of Ba2M2(PO3F)F6 (M = Mn, Co, Ni, and Cu), have been synthesized hydrothermally using phosphoric and fluorophosphoric acids. The structures of Ba2M2(PO3F)F6 were intensively investigated by single-crystal and powder X-ray diffraction. Their networks exhibited three-dimensional frameworks formed by cis-MO2F4 octahedra and PO3F tetrahedra. Ba2M2(PO3F)F6 (M = Mn, Co, and Cu) are isostructural, crystallizing in the monoclinic space group P21/c, while Ba2Ni2(PO3F)F6 adopted an unpredetermined structure, crystallizing in the monoclinic space group P21/n. The different arrangements of the same cis-MO2F4 moieties and PO3F groups within one-dimensional chains lead to different frameworks in this late-first-row transition-metal series. By a comparison of normalized bond lengths with their normal counterparts, the more elongated octahedral cis-MO2F4 units in Ba2Cu2(PO3F)F6 reveal the presence of static Jahn-Teller distortion, uncovering the puzzling reason for the exceptional structure of Ba2Ni2(PO3F)F6 in the series. Ba2M2(PO3F)F6 (M = Mn, Co, and Ni) forms spin chains of M2+ made of coupled dimers or tetramers, showing dominant antiferromagnetic behavior.

7.
Water Sci Technol ; 82(11): 2472-2481, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33339800

RESUMO

Previous studies on the extraneous water problem (or infiltration/inflow) in sanitary sewer systems assumed that the wastewater flow is mainly composed of foul sewage (FS), groundwater infiltration (GWI) and rainfall-derived inflow and infiltration (RDII). Most existing assessment methods are based on this assumption. In 2018, China initiated the 'Protection of the Yangtze River Program', and the two-year research data showed that it was neither the GWI nor the RDII but the direct surface water intrusion (DSWI), which has rarely been reported in literatures, that serves as the main source of the extraneous water in many local sewer systems. The discovery has enriched the understanding of the extraneous water in sewer systems. Meanwhile, it brings new challenges for the assessment of extraneous water. In this study, starting from the analysis of the low influent concentration of chemical oxygen demand (COD) of the wastewater treatment plant in a southeastern city in China, a river water intrusion point was successfully localized and the volume of river water intrusion was quantified by a series of field experiments. The methodology used in this study can also be applied in other areas with DSWI.


Assuntos
Rios , Esgotos , China , Cidades , Águas Residuárias , Água
8.
Water Sci Technol ; 80(2): 290-299, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31537765

RESUMO

One of the most common strategies for sewer cleaning is to generate flushing flows using flushing gates to store water in the upstream sewer pipe. Therefore it is important to obtain the flow information on the flushing waves and their eroding effects. In this study, the flow characteristics of the flushing wave and the flushing effect were investigated by a transient flow calculation using a commercial computational fluid dynamics (CFD) code. The values of bottom shear stress were obtained and the effect of several factors are discussed. The water depth and the slope were related to the release rate of the storage volume, while the flushing volume determined the flushing distance at long sewer distances. The initial downstream water level was found to dramatically reduce the flushing effect. Equations based on the storage depth were developed to estimate the flushing effect, and suggestions for the installation and operation of flushing gates are provided.


Assuntos
Eliminação de Resíduos Líquidos , Movimentos da Água , Modelos Teóricos , Esgotos , Estresse Mecânico
9.
Water Sci Technol ; 77(5-6): 1346-1354, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29528322

RESUMO

Catch basins are designed to convey surface runoff into sewer systems. They are also found to be effective in retaining sediments. A number of factors can influence catch basin sediment capture efficiency, such as sediment size distribution, flow hydraulics and catch basin design. To better understand the influence of these factors, numerical simulations using the Eulerian-Lagrangian method were conducted to provide insights into flow fields and to predict sediment capture rates. The numerical model was validated using previous experimental measurements of flow field and sediment capture rates for sediment sizes larger than 0.25 mm. The influence of catch basin designs, including the bottom sump and inflow arrangements, was also studied, and an equation was developed for predicting the capture rate.


Assuntos
Sedimentos Geológicos , Modelos Teóricos , Eliminação de Resíduos Líquidos , Drenagem Sanitária , Movimentos da Água
10.
Water Sci Technol ; 77(3-4): 647-654, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29431709

RESUMO

Determining the proper installation location of flow meters is important for accurate measurement of discharge in sewer systems. In this study, flow field and flow regimes in two types of manholes under surcharged flow were investigated using a commercial computational fluid dynamics (CFD) code. The error in measuring the flow discharge using a Doppler flow meter (based on the velocity in a Doppler beam) was then estimated. The values of the corrective coefficient were obtained for the Doppler flow meter at different locations under various conditions. Suggestions for selecting installation positions are provided.


Assuntos
Drenagem Sanitária/métodos , Movimentos da Água , Hidrodinâmica , Esgotos
11.
Asian J Psychiatr ; 91: 103831, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37988928

RESUMO

OBJECTIVE: There seems to be an association between the DRD4 48-bp VNTR polymorphisms and antipsychotic treatment response, but there is a rare reference to confirm this finding. Hence, the present study tried to investigate the association between DRD4 48-bp VNTR polymorphisms and the treatment response of antipsychotics in patients with schizophrenia in Taiwan, using a propensity score matching (PSM) method. METHODS: A total of 882 participants were enrolled in this study and completed informed consent, research questionnaires, including demographic information and the revised Chinese version Beliefs about Voices Questionnaire, and blood sampling. For descreasing of the selection bias and confounding variables, the PSM nearest neighbor matching method was used to select 765 paitents with schizophrenia (ratio of 1:8 between 85 persistent auditory hallucination and 680 controls) with matched and controlled the age and gender. RESULTS: Schizophrenia patients with DRD4 4 R homozygosity had a lower rate of good antipsychotic treatment response than the other DRD4 genotype carriers (DRD4 non-4/4). Among those 4 R homozygosity carriers, 60 cases of 503 (11.9%) retain persistent auditory hallucinations. Furthermore, this subgroup of patients is accounted for up to 70.6% of cases with poor neuroleptic treatment response. CONCLUSIONS: A poor treatment outcome for patients with the 4 R homozygosity had presented,that comparing with those DRD non-4/4 genotype carriers. DRD4 VNTR 4 R homozygosity could be a genetic biomarker to predict poor antipsychotic treatment response in schizophrenia. Patients with DRD 4/4 probably receive novel antipsychotic medications preferentially or in combination with alternative therapy, such as psychotherapy or milieu therapy.


Assuntos
Antipsicóticos , Esquizofrenia , Humanos , Esquizofrenia/tratamento farmacológico , Esquizofrenia/genética , Antipsicóticos/uso terapêutico , Receptores de Dopamina D4/genética , Repetições Minissatélites/genética , Genótipo , Alucinações/genética , Alucinações/tratamento farmacológico , Biomarcadores
12.
Nat Commun ; 15(1): 4426, 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38789507

RESUMO

Iron and phosphorus are essential nutrients that exist at low concentrations in surface waters and may be co-limiting resources for phytoplankton growth. Here, we show that phosphorus deficiency increases the growth of iron-limited cyanobacteria (Synechocystis sp. PCC 6803) through a PhoB-mediated regulatory network. We find that PhoB, in addition to its well-recognized role in controlling phosphate homeostasis, also regulates key metabolic processes crucial for iron-limited cyanobacteria, including ROS detoxification and iron uptake. Transcript abundances of PhoB-targeted genes are enriched in samples from phosphorus-depleted seawater, and a conserved PhoB-binding site is widely present in the promoters of the target genes, suggesting that the PhoB-mediated regulation may be highly conserved. Our findings provide molecular insights into the responses of cyanobacteria to simultaneous iron/phosphorus nutrient limitation.


Assuntos
Proteínas de Bactérias , Regulação Bacteriana da Expressão Gênica , Ferro , Fósforo , Synechocystis , Fósforo/metabolismo , Fósforo/deficiência , Synechocystis/metabolismo , Synechocystis/genética , Ferro/metabolismo , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Regiões Promotoras Genéticas/genética , Água do Mar/microbiologia , Homeostase , Espécies Reativas de Oxigênio/metabolismo
13.
Ear Nose Throat J ; 102(10): NP527-NP533, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34134529

RESUMO

Malignant peripheral nerve sheath tumor (MPNST) is a rare tumor that can develop on the lining of nerves and within the network of nerve fibers in different organs, and it is commonly found in the head and neck, limbs, and trunk. These tumors can occur in patients of any age. They most commonly occur in adults aged 20 to 50 years; however, fewer cases of this tumor in children have been reported. To date, no neonatal case of MPNST in the nasal cavity has been reported. Here, we report the case of a 4-day-old female newborn who presented with a nasal mass that re-enlarged after surgery and was diagnosed as MPNST of the nasal cavity on the basis of pathological results. This is the first report of MPNST in the nasal cavity of a neonate. Differential diagnosis and treatment of nasal masses have been proposed in the related literature.


Assuntos
Neoplasias de Bainha Neural , Neurofibrossarcoma , Adulto , Criança , Recém-Nascido , Humanos , Feminino , Neoplasias de Bainha Neural/diagnóstico , Neoplasias de Bainha Neural/cirurgia , Neoplasias de Bainha Neural/patologia , Cavidade Nasal/patologia
14.
ACS Omega ; 7(45): 40625-40637, 2022 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-36406550

RESUMO

Hydrogen fuel cell vehicles have always been regarded as the main direction for developing new energy vehicles in the future due to their advantages of zero emission, high cruising range, and strong environmental adaptability. Currently, although the related technologies have gradually matured, there are still many factors hindering its development. One of the main reasons is that the price of hydrogen fuel increases the cost of using vehicles, which puts it at a competitive disadvantage compared with traditional fuel vehicles and pure electric vehicles. Herein, we summarize the recent development status of hydrogen fuel cell vehicles at home and abroad, and analyze the cost and sustainability brought by the latest scientific research progress to the hydrogen production industry, which is derived from basic research on electrocatalysts used in industrial electrocatalytic water splitting with an alkaline electrolyte. Finally, the development of hydrogen fuel cell vehicles was analyzed and prospected, which is one of the main application fields of hydrogen in the future.

15.
Biomed Res Int ; 2022: 1530525, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35281594

RESUMO

Biofilm formation is easily found in patients suffered from ventilator-associated pneumonia (VAP) in neonatal intensive care unit (NICU) and makes the VAP infections not only harder to be treated but easier to relapse. In order to find some novel ways to inhibit biofilm formation, this study describe a previously unrecognized role for the human umbilical cord mesenchymal stem cells (hUCMSCs). In addition to multiple differentiation, hUCMSCs have the ability to prevent the biofilms formation in vitro by secreting antibacterial peptides (LL-37 and hBD-2). This occurred while P. aeruginosa PA27853 and hUCMSCs were cocultured, and the filtrated medium, which was the supernatant containing antibacterial peptides (5.9 ng/ml of LL-37, 1.77 ng/ml of hBD-2), and inhibited the growth of the bacterial biofilm on the surface of tracheal tube (2.5#, for preterm infant). Using microarrays, we were able to demonstrate that the antibacterial peptides from hUCMSC affected biofilm formation by downregulating the gene-encoded polysaccharide biosynthesis protein. In addition, in order to find out the most suitable concentration of hUCMSCs, P. aeruginosa was cocultured with eight-level concentrations of hUCMSCs, and we found that the concentration of LL-37 was positively correlated with the concentration of hUCMSCs. Meanwhile, the concentration of LL-37 became stable while the hUCMSC concentration reaches higher than 5 × 106 cells/ml. But the concentration of hBD-2 had no significant correlation with hUCMSCs. The collection of these stem cells is not only limited by ethics but also reduces host rejection. This makes it possible to use autologous hUCMSCs to treat neonatal VAP.


Assuntos
Células-Tronco Mesenquimais , Cordão Umbilical , Antibacterianos/metabolismo , Biofilmes , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Células-Tronco Mesenquimais/metabolismo
16.
J Psychiatr Res ; 156: 698-704, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36410308

RESUMO

Air pollution is a risk factor for increased hospital admissions due to mental disorders, while green spaces have been linked with better mental health. We linked daily hospital admission records from Wuhan's 74 municipal hospitals from 2017 to 2019 with modeled annual average NO2 concentrations and added data on the residential surrounding green spaces with 250 m and 500 m buffers based on the normalized difference vegetation index (NDVI) using a land use regression model (LUR). The conditional logistic regression model was used to estimate the acute effect of short-term NO2 exposure, and stratification analyses were applied to explore the modification effect of long-term NO2 exposure and green spaces by estimating the odds ratios in the single- and dual-environmental factor groups. A total of 42,705 hospital admissions for mental disorders were identified. Short-term exposure to NO2 was associated with an increased risk of hospital admission for mental disorders. A 10 µg/m3 increase in NO2 (lag01 day) was associated with an increase in hospital admissions of 2.86% (95% CI, 2.05-3.68) for the total mental disorders. Compared with patients in the "low-NDVI/low-NO2" group (ER = 2.27%, 95% CI, 0.27-4.31), patients in the "high-NDVI/low-NO2" group (ER = 1.93%, -0.10-3.99) showed a lower and insignificant increase in hospitalizations for the total mental disorders, while greenness had a slight moderating effect in the high-level long-term NO2 exposure areas. This study suggested that green spaces may moderate the acute effect of NO2 exposure for mental disorder hospitalizations, especially in low-level long-term NO2 exposure areas.


Assuntos
Transtornos Mentais , Parques Recreativos , Humanos , Transtornos Mentais/epidemiologia , Transtornos Mentais/terapia , Hospitais
17.
Huan Jing Ke Xue ; 42(10): 4807-4814, 2021 Oct 08.
Artigo em Zh | MEDLINE | ID: mdl-34581123

RESUMO

Viruses in the aquatic environment have strong resistance to common disinfection techniques. To contribute to the development of efficient virus inactivation technologies, the characteristics and mechanisms of virus inactivation in a UV activated sodium persulfate(UV/PS) system were studied. The inactivation rate and kinetic characteristics of bacteriophage MS2 in water samples by the UV/PS were studied. The effects of PS dosage, pH, and the initial concentration of bacteriophages on the inactivation effect were also investigated. Furthermore, the morphologies of phages before and after UV/PS treatment were observed by transmission scanning electron microscope, and the free radicals in the reaction system were identified by electron paramagnetic resonance spectroscopy. By means of a free radical quenching experiment, the contribution rate of various factors in the UV/PS system to phage inactivation was also analyzed and calculated. The results showed that when the UV irradiation intensity was 160 µW·cm-2, the phage MS2 of 4.39 lg could be removed after UV/PS treatment for 4 min, which was 1.44 lg higher than that of the same UV dose alone. The inactivation of phage MS2 by the UV/PS system was in accordance with the first-order kinetic model. Increasing the initial concentration of PS in the system significantly improved the inactivation rate of phages, while pH and the initial concentration of phages had little effect on the inactivation rate. UV/PS treatment damages the capsid of phages and promotes the aggregation of phage particles. The presence of SO4-· and·OH in the UV/PS system was an important factor for the inactivation of MS2 phages. Finally, ·OH contributed more to MS2 phage inactivation than SO4-·.


Assuntos
Levivirus , Purificação da Água , Compostos de Sódio , Sulfatos , Raios Ultravioleta , Inativação de Vírus , Água
18.
J Matern Fetal Neonatal Med ; 34(7): 1149-1154, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32627623

RESUMO

OBJECTIVE: To investigate histopathological placental lesions and adverse neonatal outcomes by Pre-eclampsia (PE) with Gestational Diabetes Mellitus (GDM). METHODS: This was a retrospective cohort study of pregnancies with PE delivered between 1 January 2012 to 1 January 2014. Pregnant women with PE were recruited, and divided into PE with GDM (PE + GDM) group (n = 278) and PE without GDM (PE - GDM) group (n = 586). We compared the placental pathology and neonatal outcomes between the two groups. RESULTS: The (PE + GDM) group was significantly associated with high placenta weight (534.8 ± 124.1 vs 519.3 ± 132.3 g, p = .011), the large diameter of the placenta (17.8 ± 2.2 vs 16.2 ± 2.7 cm, p = .016) than (PE - GDM) group. The incidence of chorioamnionitis in (PE + GDM) group was significantly higher than (PE - GDM) group [48.9% (136/278) vs 41.5% (243/586), p = .028], whereas there were no significant differences in umbilical cord length and infarction between the two groups. The (PE + GDM) group had a higher rate of prematurity [44.9% (125/278) vs 39.9% (234/586), p = .042] than (PE - GDM) group, in (PE + GDM) group the incidence of LGA [15.1% (42/278) vs 1.0% (6/586), p = .034], RDS [18.7% (52/278) vs 9.2% (54/586), p = .011] and hyperbilirubinemia [10.7% (30/278) vs 1.0% (6/586), p = .038] were higher than (PE - GDM) group. CONCLUSIONS: GDM increased the offspring's complication in pregnancy with PE, the potential mechanism might be that GDM increased the placenta inflammation.


Assuntos
Diabetes Gestacional , Pré-Eclâmpsia , Diabetes Gestacional/epidemiologia , Feminino , Humanos , Recém-Nascido , Placenta , Pré-Eclâmpsia/epidemiologia , Gravidez , Resultado da Gravidez/epidemiologia , Estudos Retrospectivos
19.
Artigo em Inglês | MEDLINE | ID: mdl-32784870

RESUMO

To analyze the time-frequency characteristics of the particulate matter (PM10) concentration, data series measured at dry bulk ports were used to determine the contribution of various factors during different periods to the PM10 concentration level so as to support the formulation of air quality improvement plans around port areas. In this study, the Hilbert-Huang transform (HHT) method was used to analyze the time-frequency characteristics of the PM10 concentration data series measured at three different sites at the Xinglong Port of Zhenjiang, China, over three months. The HHT method consists of two main stages, namely, empirical mode decomposition (EMD) and Hilbert spectrum analysis (HSA), where the EMD technique is used to pre-process the HSA in order to determine the intrinsic mode function (IMF) components of the raw data series. The results show that the periods of the IMF components exhibit significant differences, and the short-period IMF component provides a modest contribution to all IMF components. Using HSA technology for these IMF components, we discovered that the variations in the amplitude of the PM10 concentration over time and frequency are discrete, and the range of this variation is mainly concentrated in the low-frequency band. We inferred that long-term influencing factors determine the PM10 concentration level in the port, and short-term influencing factors determine the difference in concentration data at different sites. Therefore, when formulating PM10 emission mitigation strategies, targeted measures must be implemented according to the period of the different influencing factors. The results of this study can help guide recommendations for port authorities when formulating the optimal layout of measurement devices.


Assuntos
Poluição do Ar , Material Particulado , Poluição do Ar/análise , China , Material Particulado/análise
20.
Dalton Trans ; 49(28): 9751-9761, 2020 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-32618324

RESUMO

Four new alkali metal copper chlor-tellurites, [Cs(NH4)]layer[Cu4Te2O6Cl6]layer (I), [Rb3(NH4)2(OH)0.5]layer[Cu12Te6Cl16.5O18]layer (II), [K(NH4)]layer[Cu4Te2O6Cl6]layer (III) and [NaCl]layer[Cu4Te2O6Cl4]layer (IV), have been synthesized via hydrothermal reactions using mixtures of AF (A = Cs, Rb, K, Na), CuCl2·2H2O, TeO2, and hydrazine monohydrate. They have two-dimensional (2D)-layered [Cu4Te2Cl5+x-yO6]∞ (x = 0, 2/3, 1; y = 0, 1/6) structures that are separated by different layers comprised of various cations and anions, including A+, NH4+ Cl- OH-, etc. The blocks feature S-shaped ∞[Cu2O3Cl3-x] chains linked by TeO3 trigonal pyramids. The magnetic susceptibility shows a broad maximum at 220 K for I and 240 K for III, which is well simulated by using an alternating antiferromagnetic chain model. The J2/J1 ratio within the alternating chain is estimated to be 0.60(1), and the spin gaps are refined to be 152 K for I and 136 K for III.

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