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Thermal convection in nature and industrial applications usually encounters time-varying internal heating (IH); however, the effect of temporal modulation on temperature responses and heat fluxes of the system has been rarely explored. Here, we numerically studied the IH convection with a temporally periodic heating source. We conducted direct numerical simulations over Rayleigh number ( Ra) range [Formula: see text] at fixed Prandtl number Pr = 1 with dimensionless modulation frequency [Formula: see text] and amplitude fixed at Ω = 1. We first find that the introduction of periodic modulation has a slight effect on the heat transport over the individual plates and flow strength except for the lowest Ra. We then focus on the characteristics of the amplitude A and phase lag [Formula: see text] of the globally averaged temperature response to the periodic modulation. Three regimes of the phase response are identified: (i) in-phase regime, where synchronous response is found at small frequencies with the vanished phase lag [Formula: see text] and A keeping at constant value; (ii) transition regime, where both [Formula: see text] and A decrease with increasing f for moderate frequencies; and (iii) half anti-phase regime, where [Formula: see text] attains the minimal value [Formula: see text]. We also find that the transition behavior between three regimes can be well described using the normalization of the Ra-dependent critical frequency with the scaling [Formula: see text]. To explain the regime transition, we further theoretically deduce an analytical solution for A and [Formula: see text], which agrees well with the numerical results. This solution can explain why [Formula: see text] gives a good description of the transition behavior. Our present findings provide a fundamental understanding of the underlying mechanism of temporal modulation on IH systems and have substantial implications for the investigation of convective system with periodic heating source.

Background: We aimed to carry out a comprehensive multiple-center epidemiological study of post-traumatic related limb osteomyelitis (PTRLO) in China. Methods: Approved by the Institutional Research Board (IRB), 3,526 PTRLO patients were identified from 212,394 traumatic limb fracture patients from 21 hospitals between January 1st, 2008- December 31st, 2017 to conduct an epidemiological retrospective analysis, which includes dynamic changes of infection rate (IR), pathogens, infection risk factors, and antibiotics resistant and sensitivity during the past decade. Findings: The IR of PTRLO gradually increased from 0.93% to 2.16% (Z=14.392, p 0.05). The dominant strains of GP are MSSA (17.03%), MRSA (10.46%), E. faecalis (5.19%), and S. epidermidis (4.87%). The dominant strains of GN are Pseudomonas Aeruginosa (10.92%), E. cloacae (10.34%), E.coli (9.47%), Acinetobacter Baumannii (7.92%) & Klebsiella Pneumoniae (3.33%). Overall, the high-risk factors of PI are open-fracture (odds ratio, 2.223), hypoproteinemia (odds ratio, 2.328), and multiple fractures (odds ratio, 1.465). The antibiotic-resistance and sensitivity analysis of the pathogens could be influenced by the complications or comorbidities. Interpretation: The current study demonstrates the epidemiology of PTRLO of a patient population in China, and provides a useful information for patient care and clinical practice. Trial Registration: The study is registered with the Chinese clinical trials registry (ChiCTR1800017597). Funding: National Natural Science Foundation of China, Technological Innovation Projects of Southwest Hospital of China, and AO Trauma Clinical Priority Program on Bone Infection. Declaration of Interests: All other authors declare no competing interests. Ethics Approval Statement: Approved by the Institutional Research Board (IRB)

Thermal stress of porous alumina films has been simulated by finite element method based on thermal transfer equation and thermal stress formulas. The influence of equivalent thermal conductivity and elastic modulus on laser induced damage threshold (LIDT) has been studied. It was found that the biggest circumferential tensile stress will be small with the porosity from 15% to 35%, and it effectively improves the LIDT. The equivalent thermal conductivity and LIDT decreases with the increase of porosity. The equivalent elastic modulus decreases and LIDT increase with the increase of porosity.

In the solutions which are prepared by mixing zinc nitrate hexahydrate, strong ammonia and methenamine in water bath at 90 Centigrade, lamellate and granular zinc oxide films have grown on different substrates such as B270 glass, glass based PAA films, pure aluminum foil and aluminum based PAA films. Films microstructures were characterized by scanning electron microscope (SEM). The influences of substrate and pH on the films microstructure were analyzed. Results reflect that: Ammonia plays an important role in the growing competition of grainy crystal; the more concentration of ammonia, the more zinc oxide crystals grow into granular. Because of the high specific area and adsorption capacity, lacunaris zinc oxide films have great application perspective in gas sensor, catalyzed sorption and biochemistry.

Optical films have been prepared on K9 glass by electronic beam evaporation. Parameters of S-polarized Nd: YAG laser used for pretreatment and damage tests are: wavelength is 355nm, pulse width is 8ns, and incidence angle is 33.75 degree. The results reflect that: the influence of laser pretreatment on laser induced damage threshold of films is uncertain. Laser pretreatment not always improve the laser induced damage threshold of films, and sometimes it will cause negative influence. As for damage probability, for a certain testing energy density, there is an energy density scope, pretreatment pulse with energy density in which can reduce the laser induced damage probability of films. The energy density of laser pretreatment pulse should be selected according to the serving conditions of films.

Aluminum films were deposited on glass substrate by electron beam heat evaporation, and porous alumina films with high transmittance were prepared by means of anodic oxidation under different anodizing conditions in oxalic acid solution or phosphoric acid solution respectively. Thus the morphology of these porous alumina films was characterized by different structural. he optical transmittance spectrum at normal incidence over the 300~1000nm spectra region were obtained by spectrophotometer, which shows, in visible and ultraviolet light region, the transmittance of porous alumina films prepared in oxalic acid solution is much better than that prepared in phosphoric acid solution. The SEM analysis results showed that the pores are circular and uniform in porous alumina prepared in oxalic acid but irregular and non-uniform in that prepared in phosphoric acid, which affected the surface roughness of alumina films.

In past investigations on the interaction of laser and optical films, research was not widely performed on the process after the burst of the films’ material. Based on a centrosymmetric burst model of a plasma droplet, combined with ionization and absorption, the conditions that the ejected droplet’s thermodynamic parameters change with time have been investigated. When the burst starting time is appropriate, research has shown that the droplets’ parameters, such as expansion velocity and acceleration, cracking velocity and acceleration, temperature, and radius will reach their maximums. An earlier or later time does not increase the intensity of the droplet’s burst. This conclusion has great significance in investigations of laser-induced films damage.

Shenfu coal (SFC), its liquefaction residue (RL), and carbon disulfide (CS{sub 2})/tetrahydrofuran (THF)-inextractable matter (RE) were subject to ruthenium ion-catalyzed oxidation to understand the differences in structural features among the above three samples. The results suggest that SFC is rich in long-chain arylalkanes and {alpha}. {omega}-diarylalkanes (DAAs) with carbon number of methylene linkage from 2 to 4 and that long-chain arylalkanes and DAAs are reactive toward hydroliquefaction and soluble in a CS{sub 2}/THF mixed solvent, whereas highly condensed aromatic species in SFC show poor solubility in the CS{sub 2}/THF mixed solvent. 29 refs., 6 figs., 4 tabs.

Four kinds of Y2O3 stabilized ZrO2 (YSZ) thin films with different Y2O3 content have been prepared on BK7 substrates by electron-beam evaporation method. Structural properties and surface morphology of thin films were investigated by X-ray diffraction (XRD) spectra and scanning probe microscope. Laser induced damage threshold (LIDT) was determined. It was found that crystalline phase and microstructure of YSZ thin films was dependent on Y2O3 molar content. YSZ thin films changed from monoclinic phase to high temperature phase (tetragonal and cubic) with the increase of Y2O3 content. The LIDT of stabilized thin film is more than that of unstabilized thin films. The reason is that ZrO2 material undergoes phase transition during the course of e-beam evaporation resulting in more numbers of defects compared to that of YSZ thin films. These defects act as absorptive center and the original breakdown points. (c) 2006 Elsevier B.V. All rights reserved.

A new formulation derived from thermal characters of inclusions and host films for estimating laser induced damage threshold has been deduced. This formulation is applicable for dielectric films when they are irradiated by laser beam with pulse width longer than tens picoseconds. This formulation can interpret the relationship between pulse-width and damage threshold energy density of laser pulse obtained experimentally. Using this formulation, we can analyze which kind of inclusion is the most harmful inclusion. Combining it with fractal distribution of inclusions, we have obtained an equation which describes relationship between number density of inclusions and damage probability. Using this equation, according to damage probability and corresponding laser energy density, we can evaluate the number density and distribution in size dimension of the most harmful inclusions.

To study the chemical composition of Tripterygirm wilfordii Hook. f.Colunm chromatography was used to separate the chemical constituents. UV, IR, MS, HRMS, 1HNMR, 13CNMR (COM and OFR), 1H-1H COSY, 1H-13C COSY, NOESY and COLOC spectra were used to determine the structures of the isolated constituents.Two sesquiterpene alkaloids were isolated and their structures were elucidated as wilforgine and wilfordlongine on the basis of spectral evidence.Wilfordclonine is a new sesquiterpene alkaloid.