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Preventing the proliferation of highly enriched uranium (HEU) is an important issue all over the world. The active interrogation of HEU hided in the suitcase based on neutron technique is studied by using MCNP5 code. The neutron source of the detection system is based on the NG-9 neutron generator developed by Northeast Normal University. A set of HEU detection devices has been established. Lead is a kind of neutron-multiplier material with high density, so the lead block is chosen as the substitute for HEU. The size of the aluminum alloy suitcase is 58 cm × 42 cm × 25 cm. The NG-9 D-T neutron generator is placed on the suitcase. A lead block measuring 26.5 cm × 12 cm × 1 cm is placed in the center of the suitcase. The lead block has a density of 11.35 g/cm and a mass of approximately 3.6 kg. Daily clothes are placed inside the suitcase as a distraction. A cylindrical BGO detector with a diameter of 7.2 cm, a height of 29.7 cm is placed close to the suitcase to record gamma rays. A cylindrical lead shield with a thickness of 5 cm is placed outside the BGO detector. Paraffin wax is placed around the whole detection device to protect the neutron radiation and avoid the interference of other substances on the detection results. The purpose of this experiment is to verify the agreement of the MCNP5 simulation results and the experimental results. In this paper, threshold energy neutron analysis (TENA), fast neutron method, and thermal neutron method are used to detect HEU. The simulation results show that the presence of HEU in the suitcase can be determined by neutron flux which is higher than those in the absence of HEU.

Online composition analysis is a crucial method for energy-saving and environment-friendly cement industry. A prompt gamma neutron activation analysis (PGNAA) system, which is aimed to determine the elemental concentrations of cement sample, has been designed and optimized by the Monte Carlo approach. This system consists of a 2 × 2” Bismuth Germanate (BGO) scintillation detector, a portable D-D neutron generator, a multi-channel analyzer, the reflector, the moderator and the shield. Out of consideration for minimization of costs and maximization of the thermal neutron flux at the output surface, different models of reflectors and moderators were tested in the MCNP code. Meanwhile, lead shield was also designed to reduce gamma-ray background produced by the nature and the system itself. In addition, simulated spectra of a standard cement sample were obtained to test the performance of this system. For ensuring the safety of the system operators, the dose rate distribution around the system were evaluated. The results demonstrated the feasibility of adopting this optimized design for chemical composition analysis of cement sample, and provided data reference for similar research. Eventually, an in-situ system has been established for further study.

In this paper, MCNP5 code is used to establish a landmine clearance system based on pulse fast thermal neutron method. The system prototype is modeled based on the NG-9 D-T neutron generator, which is independently developed by Northeast Normal University. Gamma rays produced by fast neutron inelastic scattering and thermal neutron capture are used to identify suspicious areas. The neutron flux passing through landmine cell before and after adding neutron reflector into initial detection system is studied. The simulation results show that the addition of a neutron reflection layer hardly improves the flux of fast neutrons passing through the landmine cell during at pulse width of 10 µs; but the thermal neutron flux through the landmine cell in the pulse interval of 90 µs is significantly increased. Among the several common reflector materials, tungsten (W) and tungsten carbide (WC) materials show better reflection performance. When W and WC are used as reflector materials and the thickness is 6 cm, the thermal neutron flux through the landmine cell is 2.00 and 1.90 times the initial value, respectively. The ratio of the thermal neutron flux in the pulse interval to the fast neutron flux during the emission of the neutron pulse increased to 0.468 and 0.444, respectively, from the initial value of 0.259. Finally, the improved model is used to simulate the landmines hidden in different depths. The results show that using 4.44 MeV and 2.22 MeV peak area counts in the region of interest can identify whether there are explosives in the detection area.

The application of D-D neutron tube is increasingly widespread. The replacement of the original pure titanium target with an alloy target can effectively improve the defects such as embrittled and not flexible of titanium after hydrogen absorption. In this paper, a titanium film was prepared by magnetron sputtering and characterized by scanning electron microscope (SEM). The prepared titanium target was used to assemble D-D neutron tube. The actual operation of the neutron tube was carried out, and the neutron yield was measured with the 3He neutron monitor. The experimental results are in good agreement with the calculation results by SRIM. Subsequently, the neutron output and target sputtering yield of the D-D neutron tube with alloy targets were calculated by SRIM, and the atomic ratios of scandium-titanium, molybdenum-titanium, niobium-titanium alloy were 0.2, 0.4, 0.6, 0.8, and 1.0. The results show that the neutron yield is relatively high and the sputtering yield is low when the scandium-titanium alloy with atomic ratio of 0.4 is chosen for target material.

A prompt gamma neutron activation analysis (PGNAA) system based on a deuterium-deuterium (D-D) sealed neutron generator was designed using the MOCA code for explosive detection. The system is mainly composed of four parts: D-D sealed neutron generator, moderator, shielding, and Lutetium Yttrium OxyorthoSilicate (LYSO) scintillation detectors. Polyethylene (PE) was selected as the moderator and the optimal thickness was 7cm. Lead, PE, and boron-containing polyethylene were used as shielding materials. In the optimized model, the LYSO detector is used to measure eighteen materials, such as wood, melamine, glucose, and nylon, and so on. Firstly, the nitrogen characteristic peak of 10.8 MeV was analyzed to determine whether the material contained nitrogen. Then, the ratio of characteristic peak counts of C/O and O/N were calculated to distinguish explosives from nitrogen containing materials. Finally, dinitrobenzene, nitroglycerin, TNT, and ammonium nitrate can be separated from nitrogenous substances by a discriminant algorithm. The final device can be used to detect the chemical composition of the threat substances, and the maximum dose rate of the system meets the limits of international protection standards.

In this study, we investigated the time course in the cerebrospinal fluid (CSF) advanced oxidation protein products (AOPPs) levels in patients with aneurysmal subarachnoid hemorrhage (aSAH), and ascertained the relationship between the levels of AOPPs and early brain injury (EBI), hydrocephalus and prognosis of patients with aSAH.We measured the CSF AOPPs levels in 50 patients with aSAH at 1-3 d, 4-6 d, 7-9 d, and 10-12 d after hemorrhage. The modified Fisher grades, Hunt-Hess grades, CSF IL-6 levels, peripheral blood count of white blood cells, cerebral edema scores and hydrocephalus were used to assess the severity of brain injury. Modified Rankin Scale (mRS) scores were used to assess the prognosis. Patients with mRS scores greater than 2 were considered to have a poor outcome.CSF AOPPs levels were significantly higher in patients with aSAH with poor prognosis, compared to patients with good prognosis and peaked in the early stage. Among patients with aSAH, the levels of CSF AOPPs on days 1-3 were significantly correlated with modified Fisher grades, Hunt-Hess grades, CSF IL-6 levels, peripheral blood count of white blood cells, and cerebral edema scores. Also, in patients with hydrocephalus, early CSF AOPPs levels were significantly elevated. Levels of CSF AOPPs in aSAH patients on days 1-3, 4-6, and 7-9 were independently associated with poor prognosis at the 90-day follow-up, and the optimal area under the curve (AUC) values for CSF AOPPs levels were found on days 1-3.AOPPs may serve as the potential biomarker to assess the severity of EBI and prognosis in patients with aSAH.

The Schwartz-Neuman alternating method is employed to analyze 3D cracks in structural components with complicated geometries.The SIFs of Mode I, II and III for the mixed-mode cracks under complicated stress state are obtained from the alternating computing scheme between finite element method solution for the uncracked body and the symmetric Galerkin boundary element method solution for the crack in an infinite body. The SIFs of the different surface cracks postulated at a regular pipe and elliptical surface cracks at the nozzle-cylinder intersection of a typical reactor pressure vessel are investigated by using the Schwartz-Neuman alternating method. The comparison with other analysis models and results reported in the literature shows that the Schwartz-Neuman alternating method can efficiently and accurately evaluate SIFs of surface cracks of different shapes and depths with much smaller computational models, which indicates that the Schwartz-Neuman alternating method is an efficient method in the evaluation of the SIFs of 3D cracks.

Ocean acidification (OA) is likely to have an effect on the fertilizing potential of desert dust in high-nutrient, low-chlorophyll oceanic regions, either by modifying iron (Fe) speciation and bioavailability or by altering phytoplankton Fe requirements and acquisition. To address this issue, short incubations (4 days) of northeast subarctic Pacific waters enriched with either FeSO4 or dust and set at pH 8.0 (in situ) and 7.8 were conducted in August 2010. We assessed the impact of a decrease in pH on dissolved Fe concentration, phytoplankton biomass, taxonomy and productivity, and the production of dimethylsulfide (DMS) and its algal precursor dimethylsulfoniopropionate (DMSP). Chlorophyll a (chl a) remained unchanged in the controls and doubled in both the FeSO4-enriched and dust-enriched incubations, confirming the Fe-limited status of the plankton assemblage during the experiment. In the acidified treatments, a significant reduction (by 16–38 %) in the final concentration of chl a was measured compared to their nonacidified counterparts, and a 15 % reduction in particulate organic carbon (POC) concentration was measured in the dust-enriched acidified treatment compared to the dust-enriched nonacidified treatment. FeSO4 and dust additions had a fertilizing effect mainly on diatoms and cyanobacteria as estimated from algal pigment signatures. Lowering the pH affected mostly the haptophytes, but pelagophyte concentrations were also reduced in some acidified treatments. Acidification did not significantly alter DMSP and DMS concentrations. These results show that dust deposition events in a low-pH iron-limited northeast subarctic Pacific are likely to stimulate phytoplankton growth to a lesser extent than in today's ocean during the few days following fertilization and point to a low initial sensitivity of the DMSP and DMS dynamics to OA.

A dynamic material model is presented to characterize the mechanical behavior of rock materials under high confining pressures and high strain rates. The yield surface is defined based on the extended Drucker–Prager strength criterion and the Johnson–Cook material model. Two internal damage variables are introduced to represent, respectively, the tensile and compressive damage of rock materials. The proposed dynamic material model of rocks is incorporated into the nonlinear dynamic analysis code LS-DYNA through a user-defined material interface. Its reliability and accuracy are verified by the simulation of various basic experiments with different loading conditions. The present rock model is also applied to simulate the penetration of granite target plate by hard projectile. The typical damage and failure on the granite targets predicated by the proposed dynamic material model of rocks agree well with the experimental results. It demonstrates that the proposed model is capable of capturing the failure of rock materials.

Previous researches proved that aerosols have a significant influence on the Moderate Resolution Imaging Spectroradiometer (MODIS) cloud observation. In East China, this impact is much greater and special compared with other regions because of the frequent haze pollution. This study evaluated the impact of aerosols on cloud detection, cloud top height (CTH) and cloud optical thickness (COT) retrieval in East China primarily using the MODIS and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) observation, combined with a cloud detection rectification algorithm. The results showed that, in haze weather, MODIS misjudged large-scale of dense aerosols as "clouds", which increased the observed cloud cover by 0.4 to 0.6 in the most seriously polluted regions. Compared with the clear condition, high aerosol loading with AOD >2 would increase the misjudgment possibility by 35%. Another influence is that MODIS has a 30% higher possibility to obtain an over low CTH of high and thin clouds, and overestimate the COT of thin ice clouds by 2.15 to 3.74 under serious air pollution. Further analyzes found that the cloud detection and COT retrieval was mainly influenced by the dense aerosols, while the CTH retrieval is vulnerable to both thin and dense aerosol. This study made a quantitative measurement of the aerosol influence on MODIS cloud observation, and first made a deep explanation for the effect of air pollution density.

Physiological responses of ryegrass in cadmium-nonylphenol (Cd-NP) co-contaminated water, as well as the phytoremediation effect were studied under laboratory conditions. The experiment revealed that the biomass and chlorophyll content of ryegrass significantly declined at high concentrations of Cd

The influence of Cd on the degradation of nonylphenol (NP) by

The effect of the face and side panels of honeycomb cores on their equivalent in-plane elastic properties is studied by the numerical simulation in this paper. The numerical results show that the deformation pattern of the honeycomb core constrained by either face panels or side panels is totally different from that of pure honeycomb materials. As a result, both the face panels and the side panels of honeycomb cores significantly increase the equivalent in-plane moduli of honeycombs. The commonly used prediction model of honeycombs cannot be used for the evaluation of the additional in-plane tensile stiffness contributed from the honeycomb core. However, the prediction model for the equivalent in-plane moduli of honeycombs with the periodic displacement condition yields much better results.

Based on molecular mechanics and the stick-spiral model, this paper first presents the analytical analysis of the effective in-plane mechanical properties of both zigzag and armchair monolayer graphene sheets. We find that the equivalent in-plane elastic constants of monolayer graphene sheets are the same in the two principal directions of graphene. The effective in-plane mechanical properties of graphene are then evaluated numerically using an improved molecular structural mechanics (MSM) model, in which the flexible connections are used to characterize the bond angle variations of graphene. Furthermore, the effective bending rigidity of the beam representing a C-C bond in this improved MSM model is determined from the energy equivalence over the basic cell of graphene and the force constants given by molecular mechanics. A rigidly connected frame model with the bending stiffness of the equivalent beams for C-C bonds different from the existing structural mechanics model is also used to evaluate the mechanical properties of graphene. The flexibly connected frame model gives very good results of Youngs modulus and Poisson ratio of monolayer graphene sheet. The new rigidly connected frame model presented here also gives improved results than the existing rigidly connected frame model of graphene.

This paper studies the evaluation of the proper stress intensity factor ranges in the fracture mechanics-based fatigue analysis of the rib-to-deck welded joints of orthotropic steel decks. It is pointed out in the paper that the stress intensity factor ranges used in Paris law for the fatigue crack growth at a rib-to-deck welded joint can not be taken as a value proportional to the corresponding stress ranges since the compressive stresses are the dominant transverse stresses in the cyclic stresses under the action of truck traffics. The proper fatigue design loads to characterize the standard truck loading for the accurate calculation of the tensile transverse stresses at the rib-to-deck joints is also discussed in the paper. It is shown that the loads from two neighboring wheel-axles of heavy trucks have to be taken into account.

A new analytical approximation for diffusivity factor has been developed to deal with the angular integration of the diffuse transmission function for infrared radiation. The method is based on the bridging function theory which connects the exact results at both of the transparent and opaque limits. It is shown that the new scheme is much more accurate than any previously proposed schemes. By implemented into a one-dimensional radiative model, it is found that the new diffusivity factor can produce very accurate results in flux and cooling rate in the main spectral ranges for CO 2 , O 3 , and H 2 O. Also, the new proposed diffusivity factor is efficient in computing. Therefore, the new scheme is a proper choice to replace the constant diffusivity factor of 1.66 currently used in radiative transfer models.

Based on a new molecular structural mechanics model, the effective in-plane mechanical properties of monolayer graphene sheet is analytically analyzed in this paper. The energy equivalence between the basic cell of the atomic structure of graphene and the corresponding basic cell, defined in the homogenization of periodic cellular media, of its equivalent periodic framed structure is used to determine the mechanical properties of the equivalent structural members representing the C-C bonds of graphene. The resulting relationship between the mechanical parameters of the equivalent structural members and the force constants defined in molecular mechanics are different from those used in other molecular structural mechanics models. And these mechanical parameters yield more accurate effective mechanical properties of graphene, especially the Poisson ratio, than the existing molecular structural mechanics models.

This paper presents the finite element damage simulation of laminated plates induced by low-velocity transverse impact. The solid elements are used to model the laminae, and the solid-shell interface elements are employed to characterize the behavior of the interfacial layers of the laminated plates. The material properties of the adhesive layers are used in the solid-shell interfacial elements for the damage prediction. The simulated damage propagation agrees well with the experimental results. Therefore, the numerical results show that the solid-shell interface element is a good computational model for the interfacial layer modeling in the damage simulation.

The analytical solutions of shear flexible beams with displacement boundary conditions are derived by using the new sixth-order differential equation beam theory presented by Shi and Voyiadjis (ASME J. Appl. Mech., Vol. 78, 021019, 2011), in which the boundary layer effects are included. The accuracy of the boundary layer effects predicted by the new sixth-order beam theory is evaluated by the finite element analysis in this study. The numerical results show that the new sixth-order beam theory is capable of taking account of the displacement boundary conditions of shear deformable beams and predicting good results of the boundary layer effects induced by the displacement boundaries and the continuity constraints.

This paper gives a brief explanation of the failure mechanism of rock fragmentation in rock cutting. The JOHNSON_HOLMGIST_CONCRETE is selected as the rock material model in numerical simulation with confining pressure and damage influence introduced. We use the non-linear dynamic finite element software LS/DYNA to simulate the dynamic process of cutting rock. The cutting forces acting on disc cutter are computed. The relationship between cutting forces and penetration depth, confining pressure and damage parameters are obtained. The results show that, the cutting forces increase with the penetration depth. They are larger in equal confining pressure than unequal condition. The forces are amplified with the damage parameters increasing. The conclusion provides a reference for the prediction of the cutting forces.

This paper discusses several schemes for handling gaseous overlapping bands in the context of the correlated k distribution model (CKD). Commonly used methods are generally based on certain spectral correlation assumptions; thus they are either less accurate or less efficient and rarely apply to all overlapping bands. We propose a new treatment, which we developed from the traditional absorber amount weighted scheme and improved for application to various bands. This approach is quite efficient for treating the gaseous mixture as if it were a “single gas.” Numerical experiments demonstrate that the new scheme achieves high accuracy with a fast operating speed. To validate the new scheme, we conducted spectrally integrated calculations and sensitivity experiments in the thermal infrared region. Compared to line-by-line integration results, errors in cooling rates were less than 0.2 K/day below 70 Km and rose to 1 K/day from above 70 Km up to 100 Km; flux differences did not exceed 0.8 W/m2 at any altitude. Changes in CO2 and H2O concentrations slightly influenced the accuracy of the results.

Solar radiation is one of the most important factors affecting climate and the environment. Routine measurements of irradiance are valuable for climate change research because of long time series and areal coverage. In this study, a set of quality assessment (QA) algorithms is used to test the quality of daily solar global, direct, and diffuse radiation measurements taken at 122 observatories in China during 1957–2000. The QA algorithms include a physical threshold test (QA1), a global radiation sunshine duration test (QA2), and a standard deviation test applied to time series of annually averaged solar global radiation (QA3). The results show that the percentages of global, direct, and diffuse solar radiation data that fail to pass QA1 are 3.07%, 0.01%, and 2.52%, respectively; the percentages of global solar radiation data that fail to pass the QA2 and QA3 are 0.77% and 0.49%, respectively. The method implemented by the Global Energy Balance Archive is also applied to check the data quality of solar radiation in China. Of the 84 stations with a time series longer that 20 yr, suspect data at 35 of the sites were found. Based on data that passed the QA tests, trends in ground solar radiation and the effect of the data quality assessment on the trends are analyzed. There is a decrease in ground solar global and direct radiation in China over the years under study. Although the quality assessment process has significant effects on the data from individual stations and/or time periods, it does not affect the long-term trends in the data.

Several approaches are considered to determine the temperature effect on the absorption coefficient within a correlated k-distribution method. Taking CO 2 15 μ m in the 610– 730 cm - 1 region for example, the absorption coefficients and atmospheric cooling rates calculated using these approaches are compared with line-by-line integration. It is emphasized in this paper by numerical calculation that the effect of pressure on absorption coefficient is related to temperature and vise versa; the larger the pressure, the larger the effect of temperature on absorption coefficient. Results show that the temperature effect must be considered in radiative calculations although its effect on the absorption coefficient is much smaller than that of pressure.

There are many uncertainties in the quantitative assessment of radiative effects due to atmospheric dust aerosol and the optical properties of dust particles contribute large to them. Numerical sensitivity experiments to evaluate the impacts of optical characteristics on the radiative forcing have been performed in this study. The experiments involve the effects of refractive indices, single scattering albedo, asymmetry factor and optical depth of the dust particles. An updated data set of refractive indices representing East Asian dust and the data set recommended by World Meteorology Organization (WMO) are used in our calculations for comparison. A k-distribution model for solar and thermal radiation transfer is employed in the calculation of radiative forcing. It is found that comparing with the WMO model, East Asian dust model has stronger scattering and weaker absorption at solar regime, which leads to higher negative forcing at the top of atmosphere (TOA) in this study. The more important is the signs of radiative forcing at TOA over certain regions could be reversed for the two dust models, which emphasizes the essentiality of accurate measurements of optical properties of dust aerosols for quantitatively estimating their radiative forcing.

Numerical simulations are conducted to demonstrate that (a) correlation between spectral absorption at two levels decreases with increasing level distance; and (b) the contribution to the flux gained by one layer from another decreases rapidly with the layer separation. The combination of the two facts explains why the existence of poor correlation between distant layers produces insignificant radiative cooling rate error. Therefore, the overall accuracy of cooling rate calculations under the correlated k-distribution hypothesis is high.

To explore biomechanical properties and stress-strain of mucosa scars after cleft palate surgery.After the model of mucosa scars was made, the mucosa scars and normal mucosa were excised and examined immediately by tensionometry.The mucosa scars after cleft palate surgery were compared with normal mucosa. The Poisson's ratio of mucosa scars and normal mucosa was 0.5 and 0.49, respectively, showing no significant difference between the two groups. The ultimate Young's modulus of mucosa scars was about 24.22 MPa, however, it declined to 3.32 Mpa in normal mucosa.The mucosa scars after cleft palate surgery are biomechanically weaker than normal mucosa. It can be used for further research, such as maxillary orthognathic surgery, distraction osteogenesis, and orthodontic treatment.

A new approach to deal with diffuse radiation is presented in this paper. The atmospheric cooling rates by line-by-line method are given for different approaches to the diffusive radiation. Accuracy and calculating time among different methods are compared in some detail. The numerical results show that the formula proposed in this work is not only exact but also very simple and efficient, and that it can be widely used in the thermal radiation calculations.

A coupled two-dimensional model of the dynamics, chemistry, and radiation of the stratosphere is described. The effects of Rossby wave mixing are parameterized by externally specified coefficients Kyy, which are used consistently in the zonal mean momentum equation and the diffusion term of the tracer transport equation. Rossby wave mixing is reduced in the tropics. Transport between the tropics and midlatitudes is controlled by advection in the model. It is shown that subtropical tracer gradients [e.g., Trepte and Hitchman, 1992; Randel et al., 1993] are produced as a consequence of the difference between advective timescales in the tropics and the diffusive time scale in midlatitudes. In the annual mean, the flow of air is directed from the tropics toward midlatitudes. However, advection between tropics and midlatitudes takes place in both directions at stratospheric altitudes at any given time. Calculated temperatures show some discrepancies with observations in the polar regions. Distributions of long-lived tracers are compared with observations made by instruments aboard the Upper Atmospheric Research Satellite and data from the Atmospheric Trace Molecule Spectroscopy Experiment. Tropical and midlatitude profiles calculated by the model are in reasonable agreement with observations. The sensitivity of calculated temperatures and distributions of long-lived tracers to the choice of large-scale diffusion coefficients, Kyy, is shown to be small due to the dual role of Kyy in determining diffusive tracer transport and providing a forcing term for the mean circulation [Holton, 1986].

The degradation characteristics of decabromodiphenyl ether (BDE-209) by crude enzyme from Pseudomonas aeruginosa were investigated. The results revealed that the degradation efficiency of the intracellular enzyme excreted from this bacterial strain reached 69.22% after incubation with 1 mg x L(-1) BDE-209 for 12 h. Temperature, pH, enzyme concentration and BDE-209 concentration all influenced the ability of crude enzyme to degrade BDE-209. When the BDE-209 concentration was 1 mg x L(-1), the optimal condition for enzymatic degradation was temperature 30 degrees C and pH 7.5, and the degradation rate increased with increasing enzyme concentration. The degradation process of BDE-209 by intracellular enzyme of the strain conformed to the first-order kinetic model. The highest reaction rate was achieved when the initial concentration of BDE-209 was 1 mg x L(-1) and the half-life of this substrate was 6.9 h. In addition, the biodegradation of BDE-209 can be well described by enzymatic reaction of high concentration substrate inhibition, with a maximum substrate utilization rate of 0.133 mg x (L x h)(-1), a Michaelis-Menten constant of 0.642 mg x L(-1), and an inhibitory constant of 1.558 mg x L(-1), respectively.

To study three-dimensional finite element analysis for external midface distraction after different osteotomy in patients with cleft lip and palate (CLP).Three-dimensional FEM models of Le Fort I, II and III osteotomy in CLP patients were established. External midface distraction were simulated. An anteriorly and inferiorly directed 900 g force was applied to bilateral maxillary arch in directions 30 degrees to the occlusal plane. Biomechanical changes for the maxillary complex were investigated by means of finite element analysis.Maxillary complex was advanced after different osteotomy. Constriction of alveolar crest and palate occurred in Le Fort I osteotomy, but not in Le Fort II and III osteotomy. Clockwise rotation occurred in Le Fort I osteotomy complex. Counterclockwise rotation occurred in Le Fort II and III osteotomy complex.Three-dimensional finite element research on external midface distraction could provide reference for the preoperative design.

[1] This study examined the spatiotemporal variability of ocean primary production (OPP) in the South China Sea (SCS) for the period 1998–2006; OPP was estimated using a satellite primary production model. Estimated OPP showed variability both in multiyear averages and interannually. Peaks in average OPP in the SCS appeared in winter (January) and summer (August), with the winter peak greater than the summer peak. As for the whole SCS, both along the coast at Guangdong Province and in the central basin region, the maximum OPP peak occurred in winter with a secondary peak observed during summer. OPP values were approximately three times higher near the coastal regions than in the central basin regions. High OPP in the western SCS occurred in every summer season (June–August) and was related to the surface circulation, upwelling, and seasonal rain. A jet of high OPP that developed offshore in the western SCS was associated with coastal upwelling driven by the southwest monsoon, Vietnamese offshore current, and discharges from the Mekong River. Monthly averaged OPP from January 1998 to December 2006 in the western SCS had lowest values during the summer of 1998. This anomalous event coincided with the 1997–1998 El Nino event. Spatial and temporal variability of OPP in the SCS is influenced by physicochemical environmental conditions, such as nutrients, the depth of the mixed layer, the seasonally reversed monsoon, river discharge, upwelling, and coastal currents.

Short-wave radiative flux at top of atmosphere (TOA) changes due to aerosols. The analysis provides a new measurement perspective to an aerosol radiative effect problem dominated so far by models. Short-wave radiative fluxes at TOA from a satellite measurement CERES merged with the aerosol optical depth (AOD) from MODIS were used here to estimate direct radiative effect (DRE) of aerosols over cloud-free oceans. The results show that clear sky DRE at TOA is about 5plusmn1.2 Wm-2 over global ocean, consistence with previous studies. The spatial distribution of aerosols AOD and DRE were clearly seen from satellite observations. The study is an independent measurement-based assessment of cloud-free aerosol radiative effect that could be used as a validation tool for numerical modeling studies.

This paper documents the incorporation of the radiative effect of trace gases CH4, N2O, CF2Cl2, and CFCl3 into the National Center for Atmospheric Research community climate model (CCMl) longwave scheme, which presently includes the radiative effect of H2O, CO2, and O3. This development is intended for using the CCMl to study the combined greenhouse effect of increasing atmospheric CO2, CH4, CF2Cl2, CFCl3, and N2O. The radiative effect of the trace gases in a homogeneous layer is parameterized based on Wang and Shi's (1988) analytical expression for the total band absorptance. For an inhomogeneous path, a scaling approximation is used to calculate the effective total band model parameters. The same treatment of the overlapping gaseous absorption bands used in the present CCMl scheme is adopted for the new trace gases.

An interactive two-dimensional model of the stratosphere, consisting of a primitive equation dynamics module, a simplified HO(x) ozone model, and a full radiative transfer scheme, is used to study the effect of eddy diffusion in the model. Consideration is given to the effects of nonlocal forcing from dissipation in the model troposphere and frictional drag at mesospheric levels, mechanical damping in the stratosphere itself, and potential vorticity flux due to large scale waves. It is found that the ozone distributions generated with the model are very sensitive to the choice of values for the friction and the eddy diffusion coefficients. It is shown that reasonable latitudinal gradients of ozone may be obtained by using small values for the mechanical damping for the mid- and high-latitude stratopsphere.

Analytical expressions for the total band absorptance and absorption-coefficient distribution function for radiatively-important, atmospheric gases are derived from the Malkmus narrow-band model and the wide-band approximation of Edwards and Menard. For individual absorption bands, the expressions are functions of the band width, the mean line-half-width to spacing ratio and two parameters describing the spectral variation of the mean line intensity. Procedures to calculate these absorption band parameters directly from the AFGL absorption line data are presented. The accuracy of the formulation is demonstrated by good agreement in the 15-μm CO 2 band, the H 2 O rotational band and the 9.6-μm O 3 band for the absorptances calculated from analytical expressions, line-by-line calculations and available measurements. This formulation thus provides a useful approach to calculate the coupled radiative processes of absorption and multiple scattering due to atmospheric gases and particles.