Frontogenesis and Frontolysis of a Cold Filament Driven by the Cross-Filament Wind and Wave Fields Simulated by a Large Eddy Simulation

The variations of the frontogenetic trend of a cold filament induced by the cross-filament wind and wave fields are studied by a non-hydrostatic large eddy simulation. Five cases with different strengths of wind and wave fields are studied.The results show that the intense wind and wave fields further break the symmetries of submesoscale flow fields and suppress the levels of filament frontogenesis. The changes of secondary circulation directions—that is, the conversion between the convergence and divergence of the surface cross-filament currents with the downwelling and upwelling jets in the filament center—are associated with the inertial oscillation. The filament frontogenesis and frontolysis caused by the changes of secondary circulation directions may periodically sharpen and smooth the gradient of submesoscale flow fields.The lifecycle of the cold filament may include multiple stages of filament frontogenesis and frontolysis.

Cold filament frontogenesis and frontolysis induced by thermal convection turbulence using large eddy simulation

The frontogenetic processes of a submesoscale cold filament driven by the thermal convection turbulence are studied by a non-hydrostatic large eddy simulation.The results show that the periodic changes in the direction of the cross-filament secondary circulations are induced by the inertial oscillation.The change in the direction of the secondary circulations induces the enhancement and reduction of the horizontal temperature gradient during the former and later inertial period,which indicates that the frontogenetical processes of the cold filament include both of frontogenesis and frontolysis.The structure of the cold filament may be broken and restored by frontogenesis and frontolysis,respectively.The magnitude of the down-filament currents has a periodic variation,while its direction is unchanged with time.The coupling effect of the turbulent mixing and the frontogenesis and frontolysis gradually weakens the temperature gradient of the cold filament with time,which reduces frontogenetical intensity and enlarges the width of cold filament.

Simple procedure for assessing diffuse subarachnoid hemorrhage successfully created using filament perforation method in mice

The murine model of subarachnoid hemorrhage(SAH)is a valuable experimental tool for investigating molecular and cellular mechanisms,and the endovascular filament perforation technique can be used to simulate prominent pathophysiological features observed after human SAH;however,current validation methods for assessing an appropriate SAH model are limited.Here,we introduce a simple procedure for se-lecting a mouse model of diffuse SAH.SAH was induced in 24 mice using a standard filament perforation method.After confirming survival at 24 h,SAH was scored 0-1 based on T2*-weighted images on whole-brain magnetic resonance imaging(MRI)and visual surveillance of the cisterna magna(CM)through the dura mater.The CM-based SAH grading correlated well with a reference parameter defined by extracted brain(r^(2)=0.53,p<0.0001).The receiver operating characteristic curve revealed a sensi-tivity of 85%and a specificity of 91%for detecting diffuse SAH,with a similar area under the curve(0.89±0.06[standard error of the mean])as the MRI-based grading(0.72±0.10,p=0.12).Our data suggest that confirming an SAH clot in the CM is a valuable way to select a clinically relevant diffuse SAH model that can be used in future experimental studies.

Identification of Stability Domains for Flow Parameters in Fused Filament Fabrication Using Acoustic Emission

In Fused Filament Fabrication(FFF),the state of material flow significantly influences printing outcomes.However,online monitoring of these micro-physical processes within the extruder remains challenging.The flow state is affected by multiple parameters,with temperature and volumetric flow rate(VFR)being the most critical.The study explores the stable extrusion of flow with a highly sensitive acoustic emission(AE)sensor so that AE signals generated by the friction in the annular region can reflect the flow state more effectively.Nevertheless,the large volume and broad frequency range of the data present processing challenges.This study proposes a method that initially selects short impact signals and then uses the Fast Kurtogram(FK)to identify the frequency with the highest kurtosis for signal filtration.The results indicate that this approach significantly enhances processing speed and improves feature extraction capabilities.By correlating AE characteristics under various parameters with the quality of extruded raster beads,AE can monitor the real-time state of material flow.This study offers a concise and efficient method for monitoring the state of raster beads and demonstrates the potential of online monitoring of the flow states.

Diversity of filamentous fungi in organic layers of two forests in Zijin Mountain

A study was conducted to evaluate the cultivable filamentous fungal diversity in organic layers (L, F, and H layers) and A1 layer of two main forest types, Pinus massoniana and Liguidambar formasana mixed forest and Quercus variabilis forest, in Zijin Mountain(325?N, 11848?E), Nanjing, China. A total of 67 taxa comprising 56 Deuteromycetes, 3 Zygomycetes, 5 Asco-mycetes and 3 unidentified fungi were recognized from samples from the forest floor of the two forest types. The most abundant group was Deuteromycetes. The dominant genera in both forests were Alternaria sp., Aspergillus sp., Cladosporium sp., Mucor sp., Penicillium sp., Rhizopus sp., Gliocladium sp. and Trichoderma spp. The fungal diversity was higher in the mixed forest than that in Q. variabilis forest. For both forest types, the maximum fungal diversity was found in layer F and there existed significantly different in fungal diversity between layer F and layer L. In the mixed forest, richness of fungi isolated from needle litter (P. massoniana) was lower than that from leaf litter (L. formasana). The richness of fungi from needle litter increased with the in-crease of forest floor depth, but for leaf litter, the fungal diversity decreased with the depth of forest floor. The co-species of fungi from the two forest types, as well as from two kinds of litters in mixed forest, increased with the depth of the forest floor. The succession of fungi along with the process of decomposition was discussed here. The results also showed that litter quality was a critical factor affecting fungal diversity.

GENETIC OPTIMIZATION OF HOT FILAMENT PARAMETERS IN HFCVD SYSTEM

In HFCVD system the substrate temperature is a key factor which deeply affects the quality of diamond films. Th e magnitude and the variation of the substrate temperature must be limited in a suitable range to deposit diamond films of uniform thickness over large areas. In this paper, the hot filament parameters are investigated on the basi s of GAs to realize a good substrate temperature profile. Computer simulations d emonstrate that on parameters optimized by GAs a uniform substrate temperatur e field can be formed over a relatively large circle area with R s=10 cm.

Study on Limited Filamentous Sludge Bulking Test in A/O Activated Sludge Process

[Objective] This study aimed to make use of the limited filamentous sludge bulking characteristics to purify water quality and save energy. [Method] The effects of dissolved oxygen （DO） on sludge bulking were explored by changing the DO con- centration in the aerobiotic pool of NO system from the low load （0.25 kg COD/（kg MLSS.d）） and the medium to high load （0.55 kgCOD/（kg MLSSod））. [Result] In the NO activated sludge system, when the sludge load was 0.25 kg COD/（kg MLSS.d）, DO=1.5 mg/L, the sludge index was at around 250, while when the sludge load- ing was 0.55 kg COD/（kg MLSS.d）, DO=1.5 mg/L, the sludge index was close to 300, occurring the limited filamentous bulking. The bulked sludge still showed high removal rates to COD, SS, nitrogen and phosphorus. [Conclusion] It could improve the oxygen transfer rate and reduce the aeration rate at low DO conditions to achieve energy-saving.

基于“丝智活动”(Filamentality)的教育技术公共课教学设计应用实践

目前教育技术公共课已被国内广大教师接受且应用于教学活动中,基于简单易学的Filamentality进行教育技术公共课教学设计使教师将精力集中于对教学的设计。介绍如何应用Filamentality进行教育技术公共课教学设计,以提高教学效果。

Granulation of filamentous microorganisms in a sequencing batch reactor with saline wastewater

Proliferation of filamentous microorganisms frequently leads to operational failure for activate sludge systems. In this study, it was found that filamentous microorganisms could grow in compact granular structure with 5% sodium chloride in the substrate. In the early period of experiment, coccoid and rode-like bacteria predominated in the yellowish-brown granules, and later the white and the black granules were developed by filamentous microorganisms. The filamentous granules exhibited low porosity and fast settling velocity, and were more compact even than bacteria granules. It was hypothesized that the elevated pH in the later period might be a possible reason for the compact growth of filamentous granules. However, the bacteria granules showed the high bioactivity in terms of specific oxygen utilizing rate, and comprised of a wider diversity of compounds based on the thermogravimetric evaluation. The findings in this study demonstrated that filamentous microbes could form compact granular structure, which may encourage the utilization of filamentous microorganisms rather than the inhibition of their growth, as the latter is frequently used for sludge bulking control.

A New Giant Compsognathid Dinosaur with Long Filamentous Integuments from Lower Cretaceous of Northeastern China

A new compsognathid dinosaur, Sinocalliopteryx gigas gen. et sp. nov., is erected based on a complete skeleton from the Early Cretaceous Yixian Formation of western Liaoning, northeastern China. It shares the features with Huaxiagnathus orientalis in having a manus as long as the humerus plus radius, very large and subequally long manual claws I and H, and reduced olecranon process on the ulna. But it differs from Huaxiagnathus orientalis in having the much large size, a very long maxillary process of premaxilla not extending the vertical level of the maxillary antorbital fossa, and the proportionally longer ulna and so on. Sinocalliopteryx gigas gen. et sp. nov. represents the largest species among the known compsognathid dinosaurs, suggesting the tendency of the body enlargement in compsognathids to some extent. The long filamentous integuments are attached to the whole body of this compsognathid, confirming that such integuments evolved firstly in the basal coelurosaurs. This new giant compsognathid was a fierce carnivorous theropod, as shown further by an incomplete dromaeosaurid leg inside its abdominal cavity.

Femtosecond filamentation induced fluorescence technique for atmospheric sensing

Recent progress in filament-induced atmospheric sensing is reviewed. Self-guided propagation of ultrashort laser pulses in air induces laser filamentation. All molecules in the path of a filament can be dissociated into highly excited fragments, resulting in emission of characteristic fluorescence spectra. The fluorescence spectra provide information about the various molecules in the filaments. By using a filament-induced ＂fingerprinting＂ fluorescence technique, molecules in the atmosphere can be identified.

Stk2,a Mitogen-Activated Protein Kinase from Setosphaeria turcica,Specifically Complements the Functions of the Fus3 and Kss1 of Saccharomyces cerevisiae in Filamentation,Invasive Growth,and Mating Behavior

Setosphaeria turcica,an essential phytopathogenic fungus,is the primary cause of serious yield losses in corn; however,its pathogenic mechanism is poorly understood.We cloned STK2,a newly discovered mitogen-activated protein kinase gene with a deduced amino acid sequence that is 96% identical to MAK2 from Phaeosphaeria nodorum,56% identical to KSS1 and 57% identical to FUS3 from Saccharomyces cerevisiae.To deduce Stk2 function in S.turcica and to identify the genetic relationship between STK2 and KSS1/FUS3 from S.cerevisiae,a restructured vector containing the open reading frame of STK2 was transformed into a fus3/kss1 double deletion mutant of S.cerevisiae.The results show that the STK2 complementary strain clearly formed pseudohyphae and ascospores,and the strain grew on the surface of the medium after rinsing with sterile water and the characteristics of the complementary strain was the same as the wild-type strain.Moreover,STK2 complemented the function of KSS1 in filamentation and invasive growth,as well as the mating behavior of FUS3 in S.cerevisiae,however,its exact functions in S.turcica will be studied in the future research.

Approaches to functional genomics in filamentous fungi

The study of gene function in filamentous fungi is a field of research that has made great advances in very recent years. A number of transformation and gene manipulation strategies have been developed and applied to a diverse and rapidly expanding list of economically important filamentous fungi and oomycetes. With the significant number of fungal genomes now sequenced or being sequenced, functional genomics promises to uncover a great deal of new information in coming years. This review discusses recent advances that have been made in examining gene function in filamentous fungi and describes the advantages and limitations of the different approaches.

Construction and Virulence of Filamentous Hemagglutinin Protein B1 Mutant of Pasteurella multocida in Chickens

Pasteurella multocida, a Gram-negative nonmotile coccobacillus, is the causative agent of fowl cholera, bovine hemorrhagic septicemia, enzoonotic pneumonia and swine atropic rhinitis. Two filamentous hemagglutinin genes, fhaB1 and JhaB2, are the potential virulence factors. In this study, an inactivationfhaB1 mutant ofP. multocida in avian strain C48-102 was constructed by a kanamycin-resistance cassette. The virulence of thefhaB1 mutant and the wild type strain was assessed in chickens by intranasal and intramuscular challenge. The inactivation offhaB1 resulted in a high degree of attenuation when the chickens were challenged intranasally and a lesser degree when challenged intramuscularly. ThefhaB1 mutant and the wild type strain were investigated their sensitivity to the antibody-dependent classical complement-mediated killing pathway in 90% convalescent chicken serum. ThefhaB1 mutant was serum sensitive as the viability has reduced between untreated serum and heat inactivated chicken serum （P〈0.007）. These results confirmed that FhaB1 played the critical roles in the bacterial pathogenesis and further studies were needed to investigate the mechanism which caused reduced virulence of the fhaB1 mutant.

Preparation and characterization of ultrananocrystalline diamond films in H_2/Ar/CH_4 gas mixtures system with novel filament structure

Diamond films were prepared by hot filament chemical vapor deposition(HFCVD) in a gas mixtures system of methane, argon and hydrogen. The composition and morphology in different deposition pressures and filament structures were investigated, as well as the friction and wear-resistant properties. The sp3-bonded content was measured and nano-mechanics properties were also tested. Results of atomic force microscopy and X-ray photoelectron spectroscopy show that the diamond films whose surface roughness is less than 10 nm and sp3-bonded content is greater than 70% can be prepared by bistratal filament structure with optimized proportion of Ar. It is also shown that the friction coefficient of diamond films is 0.13 and its wear-resistant property is excellent. Nano-mechanics of films shows that its elastic modulus is up to 650 MPa and hardness can reach higher than 60 GPa. The diamond films with excellent performance have a broad application prospect in microelectromechanical systems(MEMS).

Fine-scale structures and material flows of quiescent filaments observed by the New Vacuum Solar Telescope

Study of the small-scale structures and material flows associated with solar quiescent filaments is very important for understanding the formation and equilibrium of solar filaments. Using high resolution Ha data observed by the New Vacuum Solar Telescope, we present the structures of barbs and material flows along the threads across the spine in two quiescent filaments on 2013 September 29 and on 2012 November 2, respectively. During the evolution of the filament barb, several paral- lel tube-shaped structures formed and the width of the structures ranged from about 2.3 Mm to 3.3 Mm. The parallel tube-shaped structures merged together accompanied by material flows from the spine to the barb. Moreover, the boundary between the barb and surrounding atmosphere was very neat. The counter-streaming flows were not found to appear alternately in the adjacent threads of the filament. However, the large-scale patchy counter-streaming flows were detected in the filament. The flows in one patch of the filament have the same direction but flows in the adjacent patch have opposite direction. The patches of two opposite flows with a size of about 10＂ were alternately exhibited along the spine of the filament. The velocity of these material flows ranged from 5.6 km s^-1 to 15.0 km s^-1. The material flows along the threads of the filament did not change their direction for about two hours and fourteen minutes during the evolution of the filament. Our results confirm that the large-scale counter- streaming flows with a certain width along the threads of solar filaments exist and are coaligned well with the threads.

Dependence of the length of solar filament threads on the magnetic configuration

High-resolution Ha observations indicate that filaments consist of an as- sembly of thin threads. In quiescent filaments, the threads are generally short, whereas in active region filaments, the threads are generally long. In order to explain these observational features, we performed one-dimensional radiative hydrodynamic sim- ulations of filament formation along a dipped magnetic flux tube in the framework of the chromospheric evaporation-coronal condensation model. The geometry of a dipped magnetic flux tube is characterized by three parameters, i.e., the depth （D）, the half-width （w） and the altitude （h） of the magnetic dip. A survey of the parame- ters in numerical simulations shows that when allowing the filament thread to grow in 5 days, the maximum length （Lth） of the filament thread increases linearly with w, and decreases linearly with D and h. The dependence is fitted into a linear function Lth = 0.84w --0.88D - 2.78h ＋ 17.31 （Mm）. Such a relation can qualitatively explain why quiescent filaments have shorter threads and active region filaments have longer threads.

Coexistence of unipolar and bipolar modes in Ag/ZnO/Pt resistive switching memory with oxygen-vacancy and metal-Ag filaments

In this study, the unipolar resistive switching （URS） and bipolar resistive switching （BRS） are demonstrated to be coexistent in the Ag/ZnO/Pt memory device, and both modes are observed to strongly depend on the polarity of forming voltage. The mechanisms of the URS and BRS behaviors could be attributed to the electric-field-induced migration of oxygen vacancies （Vo） and metal-Ag conducting filaments （CFs） respectively, which are confirmed by investigating the temperature dependences of low resistance states in both modes. Furthermore, we compare the resistive switching （RS） characteristics （e.g., forming and switching voltages, reset current and resistance states） between these two modes based on Vo- and Ag-CFs. The BRS mode shows better switching uniformity and lower power than the URS mode. Both of these modes exhibit good RS performances, including good retention, reliable cycling and high-speed switching. The result indicates that the coexistence of URS and BRS behaviors in a single device has great potential applications in future nonvolatile multi-level memory.

The propagation dynamics of ultraviolet light filament with Rayleigh scattering in air

In this paper we present for the first time the effects of Rayleigh scattering on the long distance propagation of ultraviolet （UV） light filament in air based on the stationary analysis. The simulation results show that the effects of Rayleigh scattering on the propagation of UV laser filaments may not be ignored. These influences are slightly dependent on the laser wavelength. We also compare the UV filament propagations at different input powers in the presence and the absence of the Rayleigh scattering and discuss the mechanisms of power loss and beam defocusing. In the absence of Rayleigh scattering, the filament propagation is determined by the oscillating behaviour of the beam size. In the presence of the scattering, the propagation lengths of filament are close to each other at different initial powers and determined by the Rayleigh scattering.

Friction Behaviors of the Hot Filament Chemical Vapor Deposition Diamond Film under Ambient Air and Water Lubricating Conditions

The friction behavior of the hot filament chemical vapor deposition（HFCVD） diamond film plays a critical role on its applications in mechanical fields and largely depends on the environment. Studies on the tribological properties of HFCVD diamond films coated on Co-cemented tungsten carbide （WC-Co） substrates are rarely reported in available literatures, especially in the water lubricating conditions. In this paper, conventional microcrystalline diamond（MCD） and fine-grained diamond（FGD） films are deposited on WC-Co substrates and their friction properties are evaluated on a reciprocating ball-on-plate tribometer, where they are brought to slide against ball-bearing steel and copper balls in dry and water lubricating conditions. Scanning electron microscopy（SEM）, atomic force microscopy（AFM）, surface profilometer and Raman spectroscopy are adopted to characterize as-deposited diamond films; SEM and energy dispersive X-ray（EDX） are used to investigate the worn region on the surfaces of both counterface balls and diamond films. The research results show that the friction coefficient of HFCVD diamond films always starts with a high initial value, and then gradually transits to a relative stable state. For a given counterface and a sliding condition, the FGD film presents lower stable friction coefficients by 0.02-0.03 than MCD film. The transferred materials adhered on sliding interface are supposed to have predominate effect on the friction behaviors of HFCVD diamond films. Furthermore, the effect of water lubricating on reducing friction coefficient is significant. For a given counterpart, the stable friction coefficients of MCD or FGD films reduce by about 0.07-0.08 while sliding in the water lubricating condition, relative to in dry sliding condition. This study is beneficial for widespread applications of HFCVD diamond coated mechanical components and adopting water lubricating system, replacing ofoil lubricating, in a variety of mechanical processing fields to implement the green production process.