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Assisted reproductive technology (ART) is the most widely used treatment for infertility and has resulted in millions of births worldwide. The safety of the offspring has been of the utmost concern. Previous studies suggested an increase in metabolic disorders in offspring later in life. The aim of the present study was to investigate metabolic changes at age 6–10 years in offspring conceived as a result of in vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI). A total of 380 children born from IVF/ICSI and a matched control group of 380 naturally conceived children, all aged 6–10 years, were recruited. Anthropometric measures, ultrasound and serum tests were performed for body mass, glucose metabolism and lipid profiles, and examination of vasculature structure. The children conceived by ART showed significantly higher fasting blood glucose and serum insulin levels and HOMA-IR (adjusted β [95% CI]: fasting blood glucose 0.49 [0.42, 0.55]; loge-transformed insulin 0.28 [0.20, 0.35]; loge-transformed HOMA-IR 0.38 [0.30, 0.46]), as well as a lower HOMA-B and serum apolipoprotein A (ApoA) levels (adjusted β [95% CI]: loge-transformed HOMA-B −0.19 [−0.27, −0.11]; ApoA −0.17 [−0.21, −0.13]), when compared with the control group. Furthermore, the ultrasound scan indicated elevated carotid intima–media thickness in children conceived by ART (β 0.13 [95% CI 0.12, 0.13]). Children conceived by IVF/ICSI have a less favourable glucose and cardiovascular metabolic profile in childhood when compared with naturally conceived children. The underlying mechanisms and potential long-term consequences need to be elucidated in future studies.

OBJECTIVE The clinical utility of screening for pediatric metabolic syndrome (MetS) in children and adolescents is still controversial. We examined the performance of pediatric MetS vs. clustering of cardiovascular risk factors (which are the components of MetS) for predicting high carotid intima-media thickness (cIMT) in children and adolescents. METHODS Participants included 2427 children and adolescents aged 6-17 years from population-based studies in three countries (Brazil, China and Italy). Pediatric MetS was defined using either the modified National Cholesterol Education Program Adult Treatment Panel III criteria or the modified International Diabetes Federation criteria. Clustering of cardiovascular risk factors was calculated as the sum of five components of MetS (i.e. central obesity, elevated blood pressure, elevated triglycerides, reduced HDL-cholesterol and elevated fasting blood glucose). High cIMT was defined as cIMT at least 95th percentile values for sex and age developed from European children. RESULTS Presence of one, two or at least three cardiovascular risk factors (using the National Cholesterol Education Program Adult Treatment Panel III criteria), as compared with none, was associated with gradually increasing odds of high cIMT [odds ratios (95% confidence intervals): 1.60 (1.29-1.99), 2.89 (2.21-3.78) and 4.24 (2.81-6.39), respectively]. High cIMT was also associated with presence (vs. absence) of MetS (odds ratio = 2.88, 95% confidence interval = 1.95-4.26). However, clustering of cardiovascular risk factors predicted high cIMT markedly better than MetS (area under the curve of 0.66 vs. 0.54, respectively). Findings were similar using the International Diabetes Federation criteria for pediatric MetS. CONCLUSION In children and adolescents, a graded score based on five cardiovascular risk factors (used to define MetS) predicted high cIMT markedly better than MetS. These findings do not support the clinical utility of MetS for screening youth at increased cardiovascular risk, as expressed in this study by high cIMT.

OBJECTIVE It has been argued that metabolically healthy obesity (MHO) does not increase cardiovascular disease (CVD) risk. This study examines the association of MHO with carotid intima-media thickness (cIMT), a proxy of CVD risk, in children and adolescents. RESEARCH DESIGN AND METHODS Data were available for 3,497 children and adolescents aged 6–17 years from five population-based cross-sectional studies in Brazil, China, Greece, Italy, and Spain. Weight status categories (normal, overweight, and obese) were defined using BMI cutoffs from the International Obesity Task Force. Metabolic status (defined as “healthy” [no risk factors] or “unhealthy” [one or more risk factors]) was based on four CVD risk factors: elevated blood pressure, elevated triglyceride levels, reduced HDL cholesterol, and elevated fasting glucose. High cIMT was defined as cIMT ≥90th percentile for sex, age, and study population. Logistic regression model was used to examine the association of weight and metabolic status with high cIMT, with adjustment for sex, age, race/ethnicity, and study center. RESULTS In comparison with metabolically healthy normal weight, odds ratios (ORs) for high cIMT were 2.29 (95% CI 1.58–3.32) for metabolically healthy overweight and 3.91 (2.46–6.21) for MHO. ORs for high cIMT were 1.44 (1.03–2.02) for unhealthy normal weight, 3.49 (2.51–4.85) for unhealthy overweight, and 6.96 (5.05–9.61) for unhealthy obesity. CONCLUSIONS Among children and adolescents, cIMT was higher for both MHO and metabolically healthy overweight compared with metabolically healthy normal weight. Our findings reinforce the need for weight control in children and adolescents irrespective of their metabolic status.

Magnetopause flux ropes (FRs) play a crucial role in the transport of energy and plasma from the solar wind to the Earth's magnetosphere. Once formed by multiple X-line reconnection, the FRs move poleward, during which they can coalesce with each other through a re-reconnection process. The poleward moving FRs eventually coalesce into the cusp regions, through another re-reconnection process. In this paper, using three-dimensional (3-D) global hybrid simulations, we study the two re-reconnection processes of magnetopause FRs by examining the topological changes of magnetic field lines. These re-reconnection processes are essentially 3-D. Two FRs coalesce with each other and form two new FRs (instead of one new FR in the two-dimensional regime). When FRs move close to the cusp region, their field lines can reconnect with the cusp field lines so that the FRs can break into two shorter ones. The two re-reconnection processes increase the plasma energy and the magnetic flux connected to the Earth, which favors particle and energy transport toward the Earth's magnetosphere.

Electromagnetic ion cyclotron (EMIC) waves are one commonly observed plasma waves in the Earth's inner magnetosphere and play a crucial role in particle dynamics in the radiation belt and ring current. EMIC waves are excited by a proton temperature anisotropy and generally have a left-handed polarization, however satellite observations have usually reported the existence of linearly polarized EMIC waves in the inner magnetosphere. In this paper, we employ a two-dimensional (2D) hybrid code in a dipole field (gcPIC-hybrid) to simulate the propagation of EMIC waves from the equatorial source region. We track one single EMIC wave packet and analyze how its properties evolve along its trajectory. In diagnosing the wave normal angle (WNA) of the packet, we propose a novel method called Wave Front Shape Identification (WFSI). The ellipticity can also been calculated after we know the WNA. By comparing the ellipticity calculated from the linear theory and the ellipticity diagnosed from the simulation, we conclude that in a proton-electron plasma, EMIC waves would turn from a left-handed polarization to a linear polarization solely due to the propagation effect when the waves propagate toward higher latitudes and become oblique. We also find that the peak frequency of the wave packet (the wave mode with the maximum amplitude) decreases when propagating toward higher latitudes, which is due to different growth and damping behavior of different modes.

Marine shale is one of the main reservoirs of shale gas. A large number of marine shales were developed in the Lower Silurian in Pengshui area of southeast Sichuan Basin. Types and spatial distribution of gas-bearing shale are key factors to the exploration and development of shale gas. Based on the results of TOC and total rock analysis of samples from cored well and outcrop sections, a quantitative classification standard for shale is established for gas-bearing shales in the area of Pengshui. TOC, quartz and clay minerals content which reflecting shale sedimentary characteristics and environment are selected as three evaluation parameters in this standard. According to this standard, Longmaxi Formation gas-bearing shales in Pengshui area are divided into five types: quartz-rich clay-bearing organic shale, quartz-rich clay organic shale, quartz clay organic, quartz clay-bearing organic shale and quartz clay organic-bearing shale. The intersection diagram of TOC and gas content of different shale in typical well shows that quartz-rich clay-bearing organic shale and quartz clay-bearing organic shale have high gas content and are the most favorable shale types for shale gas exploration, followed by quartz clay organic shale. The planar distribution of various shales is obtained by synthesizing the planar TOC content equivalent map, quartz content equivalent map and clay minerals equivalent map. The results show that quartz-rich clay-bearing organic shale is developed in southwest of Daozhen County and an area from Zouma Town to Zhufo Town in Pengshui, which is the most favorable shale gas exploration area. Quartz clay organic shale is developed in the periphery of the above regions, which is the second favorable shale gas exploration area. The method to determine the types of gas-bearing shale and favorable shale distribution area is of great significance to the selection of shale gas exploration in similar areas.

Flux ropes are ubiquitous at Earth's magnetopause and play important roles in energy transport between the solar wind and Earth's magnetosphere. In this study, structure and coalescence of the magnetopause flux ropes formed by multiple X line reconnection in cases with different southward interplanetary magnetic field (IMF) clock angles are investigated by using three-dimensional global hybrid simulations. As the IMF clock angle decreases from 180 degrees, the axial direction of the flux ropes becomes tilted relative to the equatorial plane, the length of the flux ropes gradually increases, and core field within flux ropes is formed by the increase in the guide field. The flux ropes are formed mostly near the subsolar point and then move poleward toward cusps. The flux ropes can eventually enter the cusps, during which their helical structure collapses, their core field weakens gradually, and their axial length decreases. When the IMF clock angle is large (i.e., the IMF is predominantly southward), the flux ropes can coalesce and form new ones with larger diameter. The coalescence between flux ropes can occur both near the subsolar point when they are newly formed and away from the subsolar point (e.g., in the southern hemisphere) when they move toward cusps. However, when the IMF clock angle is small (

Additional file 1

Simulation dataset of "Gap formation around 0.5Ωe of whistler-mode waves excited by electron temperature anisotropy",including electric fields and magnetic fields data, and energetic electron velocity data.

To make full use of parallel ability of multicore for ensuring the real-time system reliability constraints and low power consumption, a novel non-dependent directed acyclic graph algorithm was given based on coarse-grained software pipelining, which could transform a periodic dependency task graph into a set of independent tasks with retiming technique.

著者人数: 26名, Accepted: 2020-01-05, 資料番号: SA1190192000

Whistler mode chorus waves in the Earth's inner magnetosphere are usually composed of discrete elements, and each element can be characterized by the following properties: the amplitude, the duration, the frequency span, and the frequency chirping rate. Using a one-dimensional (1-D) particle-in-cell (PIC) simulation code, we study the dependence of these properties of a rising-tone chorus on the number densityn(heq)/n(c0)and temperature anisotropyA(T)of energetic electrons at the magnetic equator. The whistler waves are first excited around the magnetic equator by anisotropic energetic electrons and then develop into a rising-tone chorus when they leave away from the equator. During the propagation toward the pole, the rising-tone chorus with nearly constant frequency span first enhances and then decays. Its frequency chirping rate declines in the early stage and then gradually increases. Meanwhile, the chorus duration is quite the opposite due to propagation effect. Over a suitable range ofn(heq)/n(c0)to generate rising-tone chorus, the frequency chirping rate of the excited rising-tone chorus first increases and then saturates, while its saturated amplitude, duration, and frequency span have a rising tendency with the increasingn(heq)/n(c0). As forA(T), the frequency chirping rate of the generated rising-tone chorus is increasing with the increase ofA(T)that is consistent with prediction of nonlinear theory, while the duration is just the opposite. Our simulation study can give a further understanding of the generation and propagation of rising-tone chorus waves.

In this paper, whether the coal fines can be induced by shear failure during drainage process has been discussed in detail. By coupling with the percolation theory, the elasticity mechanics were used to construe the extra stresses in the formation surrounding with the hydraulic fracture. The safe window of the bottom hole pressure was also calculated from the failure envelope. The research shows that the formation pressure on the fracture surface of the coal seam is negatively related with the bottom hole pressure, and the induced stress is positively related with the bottom hole pressure during the drainage process of fractured CBM wells. The pore pressure around the fracture changed due to pore-elastic effects, which also caused a significant change of the in situ stresses. In order to avoid the breakout of the coal seam around hydraulic fracture during drainage process, the model of the reasonable bottom hole pressure is also built.

Background Pediatric hypertension is typically defined as blood pressure ≥ sex-, age-, and height-specific 95th percentile (high) cutoffs. Given the number of strata, there are hundreds of cutoffs for defining elevated and high blood pressure that make it cumbersome to use in clinical practice. This study aimed to evaluate the utility of the static cutoffs for pediatric hypertension (120/80 mm Hg for children and 130/80 mm Hg for adolescents) in determining high carotid intimamedia thickness (cIMT) in children and adolescents. Methods Data were from 6 population-based cross-sectional studies in Brazil, China, Greece, Italy, Spain, and the United Kingdom. A total of 4280 children and adolescents, aged 6 to 17 years, were included. High cIMT was defined as cIMT ≥ sex-, age- and cohort-specific 90th percentile cutoffs. Results Compared with normal blood pressure, hypertension defined using the percentile-based cutoffs from 2017 American Academy of Pediatrics guideline, and the static cutoffs were associated with similar higher odds for high cIMT (percentile-based cutoffs: odds ratio [OR], 1.46, 95% confidence interval [CI], 1.15-1.86; static cutoffs: OR, 1.65, 95% CI, 1.25-2.17), after adjustment for sex, age, race/ethnicity, body mass index, high-density lipoprotein-cholesterol, triglyceride, and fasting blood glucose. The similar utility of 2 definitions in determining high cIMT was further confirmed by area under the receiver operating characteristic curve and net reclassification improvement methods (P for difference > 0.05). Conclusion Static cutoffs (120/80 mm Hg for children, 130/80 mm Hg for adolescents) performed similarly compared with percentile-based cutoffs in determining high cIMT, supporting the use of static cutoffs in identifying pediatric hypertension in clinical practice.

Rising-tone chorus waves have already been successfully produced in a mirror magnetic field with the use of one- and two-dimensional particle-in-cell (PIC) simulations. However, in reality, the background magnetic field in the inner Earth's magnetosphere is a dipole magnetic field, unlike symmetric mirror fields. In this paper, with the two-dimensional (2-D) general curvilinear PIC (gcPIC) code, we investigate the generation of rising-tone chorus waves in the dipole magnetic field configuration. The plasma consists of three components: immobile ions, cold background, and hot electrons. In order to save computational resource, the topology of the magnetic field is roughly equal to that at L = 0.6 R-E, although the plasma parameters corresponding to those at L = 6 R-E (R-E is the Earth's radius) are used. Whistler mode waves are first excited around the magnetic equator by the hot electrons with a temperature anisotropy. The excited whistler mode waves propagate almost parallel and antiparallel to the background magnetic field in their source region, which is limited at vertical bar lambda vertical bar

Background: Pediatric blood pressure (BP) levels are typically assigned to categories when they exceed sex-, age-, and height-specific 90th (elevated) and 95th percentile (high) cutoffs. Given the number of stratum, there are hundreds of cutoffs for defining elevated and high BP that make it cumbersome to use in clinical practice. In 2017 the American Academy of Pediatrics (AAP) recommended simplified cutoffs of ≥120/80 mmHg and ≥130/80 mmHg be used to diagnose elevated BP and high BP, respectively, in clinical practice for adolescents aged 13-17 years. Accordingly, we suggest cutoffs of ≥110/70 mmHg and ≥120/80 mmHg be used for elevated BP and high BP among children aged 6-12 years. The aim of this study was to evaluate the utility of the simplified cutoffs for pediatric BP in determining high carotid intima-media thickness (cIMT) in children and adolescents. Methods: Data were from 6 population-based cross-sectional studies in Brazil, China, Greece, Italy, Spain and the UK. A total of 4280 children and adolescents aged 6-17 years were included. High cIMT was defined as cIMT ≥sex-, age- and cohort-specific 90th percentile cutoffs. Logistic regression model, receiver operating characteristic (ROC) curve and net reclassification improvement (NRI) methods were used to compare the performance of the simplified definition with three established complex definitions (i.e. 2017 AAP guideline, 2004 Fourth Report, and 2016 international BP references) in determining high cIMT (≥sex-, age- and cohort-specific 90th percentile of cIMT) in children and adolescents. Results: Compared with those who had normal BP, participants with high BP defined using either of the three complex definitions or simplified definition had similar odds of high cIMT, with odds ratios and 95% confidence intervals of 1.46 (1.15-1.86), 1.47 (1.10-1.96), 1.42 (1.12-1.80), and 1.65 (1.25-2.17), respectively, after adjustment for sex, age, race/ethnicity, body mass index, high density lipoprotein-cholesterol, triglyceride, and fasting blood glucose. The similar utility of all four high BP definitions in determining high cIMT were further confirmed by area under the ROC curve and NRI methods (all p for difference >0.05). Interpretation: The simplified BP definition performed similarly with three complex definitions in determining high cIMT in children and adolescents. The simplified definition offers a similarly accurate but more convenient means to identify pediatric high BP in clinical practice. Funding: Dr Bo Xi was supported by the National Natural Science Foundation of China (81673195). Dr. Costan G. Magnussen was supported by a National Heart Foundation of Australia Future Leader Fellowship (100849). Declaration of Interest: None Ethical Approval: Each study was approved by the corresponding institutional review board, and written informed consent was obtained from all study participants and their parents or guardians.

The actual meshing state of Planetary Roller Screw will change, then the pre-setting meshing state could not be ensured and backlash or pre-tightening will appear, when the sizes of the tooth figure vary with the manufacture error. Therefore, a vector method is proposed to quantify meshing state of planetary roller screw, in order to precisely describe the meshing state. Using the relative position of Roller, Nut and Screw, the space meshing coordinate system is set up through coordinate transformation. The meshing vector equation of any parameters conditions of planetary screw pair, is deduced from the space meshing principle, and the meshing relationship of roller, screw and nut will be determined. Then the equation is solved by Newton-Raphson iterative algorithm, the precision of the solution is 10–15 millimeter, and the meshing state, backlash or interference can be quantified accurately. Based on this, the effect of the error of tooth figure, including arc radius of roller, helix angle, half angle of tooth figure and geometric pitch diameter for meshing state of planetary roller screw is discussed.

An analytical model of cutting forces was established in end milling of curved geometries During the cutting process where the curvature of the workpiece geometry varies, cutting parameters such as the instantaneous undeformed chip thickness, the federate, entry and exit angles too vary along the tool path. Taken the curved geometries into account, the cutting process was discretized into a series of steady-state cutting process at intervals of the feed per tooth. Based on the steady-state cutting process, the mathematical expressions for the federate, entry and exit angles were obtained and Fourier series expansion was utilized to derived the cutting forces model. A PCrNi3MoVA component with curved geometry was machined. Compared with the experimental results, validity of the cutting force model was demonstrated.

Recently, the generation of rising-tone chorus has been implemented with one-dimensional (1-D) particle-in-cell (PIC) simulations in an inhomogeneous background magnetic field, where both the propagation of waves and motion of electrons are simply forced to be parallel to the background magnetic field. In this paper, we have developed a two-dimensional (2-D) general curvilinear PIC simulation code and successfully reproduced rising-tone chorus waves excited from an anisotropic electron distribution in a 2-D mirror field. Our simulation results show that whistler waves are mainly generated around the magnetic equator and continuously gain growth during their propagation toward higher-latitude regions. The rising-tone chorus waves are observed off the magnetic equator, which propagate quasi-parallel to the background magnetic field with the wave normal angle smaller than 25 degrees. Due to the propagating effect, the wave normal angle of chorus waves is increasing during their propagation toward higher-latitude regions along an enough curved field line. The chirping rate of chorus waves is found to be larger along a field line with a smaller curvature.

In this paper, we perform a 1-D particle-in-cell (PIC) simulation model consisting of three species, cold electrons, cold ions, and energetic ion ring, to investigate spectral structures of magnetosonic waves excited by ring distribution protons in the Earth's magnetosphere, and dynamics of charged particles during the excitation of magnetosonic waves. As the wave normal angle decreases, the spectral range of excited magnetosonic waves becomes broader with upper frequency limit extending beyond the lower hybrid resonant frequency, and the discrete spectra tends to merge into a continuous one. This dependence on wave normal angle is consistent with the linear theory. The effects of magnetosonic waves on the background cold plasma populations also vary with wave normal angle. For exactly perpendicular magnetosonic waves (parallel wave number k(parallel to) = 0), there is no energization in the parallel direction for both background cold protons and electrons due to the negligible fluctuating electric field component in the parallel direction. In contrast, the perpendicular energization of background plasmas is rather significant, where cold protons follow unmagnetized motion while cold electrons follow drift motion due to wave electric fields. For magnetosonic waves with a finite k(parallel to), there exists a nonnegligible parallel fluctuating electric field, leading to a significant and rapid energization in the parallel direction for cold electrons. These cold electrons can also be efficiently energized in the perpendicular direction due to the interaction with the magnetosonic wave fields in the perpendicular direction. However, cold protons can be only heated in the perpendicular direction, which is likely caused by the higher-order resonances with magnetosonic waves. The potential impacts of magnetosonic waves on the energization of the background cold plasmas in the Earth's inner magnetosphere are also discussed in this paper.

During the process of vertical oil quenching, the sides of a shaft with the same effective thickness often do not obtain the same quench cooling effect. Therefore, the quench cooling effect of such workpieces can only be described with the distribution of measured values on the whole surface instead of measured values at individual spots. This is the holistic problem of the quenching effect of such workpieces. The main hazard caused by this type of holistic phenomenon is the creation of serious and regular uneven longitudinal quenching hardness, from inside out on the shaft. The holistic problem is caused by two factors: (1) the gas flow within the vapor blanket and (2) the order of the transition of vapor blanket to nucleate boiling on the surface of the workpiece. Through experimental observation, analysis, and inference, a general model is summarized for the holistic problem of workpieces with shafts of different lengths in the quenching process. By using the general model and the law disclosed by it, a new technique is developed to solve the holistic problem of the workpieces. With the new technique, higher and more uniform quenching hardness can be achieved, the quenching period of the workpiece can be shortened substantially, and steels with lower hardenability can be used to make the workpieces and achieve the same hardening effect. Moreover, oil quenching can replace induction quenching and achieve the same case hardening effect. By comparing the characteristics of the holistic problem and the distortion problem of workpieces in quenching, we arrived at two inferences: (1) quenching distortion and the holistic phenomenon have the same driving factors and (2) quenching distortion is just one of the detriments caused by the holistic problem. Therefore, the quenching distortion problem of most workpieces can be solved by the angle of their holistic problems.

Hydrolysis of diethyl 6-chloro-2-pyridinephosphonate in HCl solution affords 6-hydroxy-2-pyridinephosphonic acid (H2hppa 1). In the structure, extensive hydrogen bonding interactions link the phosphonic acid molecules into a two-dimensional network. Reactions of H2hppa and cobalt acetate under hydrothermal conditions result in a new cobalt phosphonate Co(hppa)(H2O) (2). Compound 2 shows a layer structure, in which {Co2O2} dimers are connected through the corner-sharing of {CoO5N} octahedra and {PO3C} tetrahedra, forming an inorganic double-layer. Introduction of a second ligand (1,4-bis(imidazol-1-ylmethyl)benzene, L) in the reaction system, compound [Co(hppa)(L)0.5(H2O)]·H2O (3) was obtained. In this structure, Co2+ ions are bridged by O–P–O bridges into an inorganic layer and the layers are pillared up by 1,4-bis(imidazol-1-ylmethyl)benzene. Magnetic study suggests that the existence of weak ferromagnetic coupling between Co2+ ions in the {Co2O2} unit for 2. For compound 3, O–P–O bridges mediate very weak antiferromagnetic interactions.

The paper studied the sedimentary system of No.1 and No.2 structure in Nanpu oil field with methods of geological, logging, seismic and chemical analysis, associated with core characteristics, sedimentary structure, profile structure and logging facies. The results demonstrate the following three points. First, Minghuazhen Formation in Nanpu field is meandering river sedimentary, and the channel subphase can be further divided into channel bottom lag deposits, beach, abandoned channel and natural levee. Second, the isopach and sedimentary face map of Minghuazhen Formation are generated based on each well's thickness of sand body and curve characteristics, and show the trend of North West and South West distribution. Third, sand body distribution can be predicted though spatial distribution of sedimentary face. And linear reservoir and Barrage-type reservoir are the two typical zones of Minghuazhen Formation.

Reactions of Co(ClO4)2·6H2O with 2-pyrazinephosphonic acid (2-paPO3H2) under two different hydrothermal conditions gave two new cobalt 2-pyrazinephosphonates, Co(2-paPO3H)2 (1) and Co(2-paPO3)(H2O) (2). Compound 1 was obtained at 160 °C, while 2 was obtained at 180 °C. In 1, two Co(II) units are bridged by two O–P–O’s into a dimer and the dimers are linked by pyrazinyl groups into a 1-D double chain. In 2, the {CoO4N2} and {CPO3} polyhedra are interconnected via edge and corner-sharing into a metal phosphonate layer, and the layers are pillared by pyrazinyl groups into a 3-D network. Variable-temperature magnetic susceptibility studies reveal that both complexes have weak antiferromagnetic coupling between Co(II) ions.

In this study, we are developing a power add-on unit PAU for attendant propelled wheelchairs with sensorless speed control and power assistance to help an attendant who are pushing a conventional commercialized manual wheelchair in which a patient is sitting in the wheelchair. This development is based on the following three concept: to make our PAU 1 easy to be attached to and detached from the wheelchair; 2 able to be used to the most of the conventional commercialized wheelchairs; 3 low cost. Further, in order to make the attendant more easily and comfortably propel the wheelchair, a sensorless power assistance approach is proposed. The experimental results verify the effectiveness of the proposed approaches.

Three-dimensional printing (3D printing) is commonly used as a means of rapidly producing prototypes for manufacturing technology, which can further be personalized or customized products, since it is suitable for the design and manufacture of complicated structure. Now 3D printing can be used to

With one-dimensional (1-D) hybrid simulations we investigate the nonlinear evolution of the ion cyclotron waves excited by the H+ and He2+ temperature anisotropies, and analyze the evolution by using the wavelet analysis method. The results show that the proton cyclotron waves with the dominant frequency higher than the helium gyro-frequency (?He = 0.5?p, with ?p and ?He the proton and helium gyro-frequencies respectively) are firstly excited, and then the helium cyclotron waves with the dominant frequency lower than the helium gyro-frequency are excited. The relation of our simulation results to the BIF(bifurcated) (there are two peaks in the wave spectrum: one above and one below ?He) and CON(continuous) (continuous spectrum from 0.1 ?p to 1.0 ?p) wave spectra observed in the magnetosheath are discussed.

Using the two-fluid model in the case of α 1 (α = β/2Q, β is the ratio of thermal pressure to magnetic pressure, and Q = me/mi), we numerically investigate the interactions between two solitary kinetic Alfven waves (SKAWs) and between an SKAW and a density discontinuity. The results show that the two SKAWs would remain in their original shapes and propagate at their initiating speeds, which indicates that SKAWs behave just like standard solitons. The simulation also shows that SKAWs will reflect and refract when crossing a discontinuity and propagating into a higher density region. The transmission wave is an SKAW with increasing density, and the reverberation is a disturbance with lower amplitude.

We perform 2.5-dimensional particle-in-cell simulations to investigate the nonlinear evolution of the lower hybrid drift instability (LHDI) in Harris current sheet. Due to the drift motion of electrons in the electric field of the excited low hybrid drift (LHD) waves, the electrons accumulate at the outer layer, and therefore there is net positive charge at the inner edge of the current sheet. This redistribution of charge can create an electrostatic field along the z direction, which then modifies the motions of the electrons along the y direction by E × B drift. This effect strongly changes the structure of the current sheet.

Wenhua is an important genre of Chinese classical literary criticism. Besides the form of collections of tales and notes, as defined in a narrow sense, there are different writing formats of Wenhua, including theoretical monographs, compilations of sources, annotated and commented anthologies, etc. The four types of critical writings emerged simultaneously in the Song dynasty, thus signified the founding of Chinese classical article-logy and then grew in abundance in the Ming and Qing dynasties. They are rich in insights and artistic experience in the aspects of literature-Tao relationship, manner of writing, poetic state of the prose, genre, writing skills and criticism. After the reflection of “May-fourth Movement”, evaluation of the merits of Wenhua is supposed to be more comprehensive and scientific.

We further present a three-dimensional (3D) ray-tracing study on the propagation characteristic of the superluminous R-X mode waves during high geomagnetic activity following our recent two-dimensional results [J. Geophys. Res. 112 (2007) A10214]. We perform numerical calculations for this mode which originates at specific altitude r = 2.0RE in the source cavity along a 70° night geomagnetic field line. We demonstrate that the ray path of the R-X mode is essentially governed by the azimuthal angle of the wave vector k. Ray paths starting with azimuthal angle 180° (or in the meridian plane) can reach the lowest latitude, but stay at relatively higher latitudes with the azimuthal angles other than 180° (or off the meridian plane). The results further supports the previous finding that the R-X mode may be physically present in the radiation belts under appropriate conditions.

The ion motion in the presence of linear polarized Alfven waves is studied. For a linearly polarized wave, nonlinear resonances can occur when the amplitude of Alfven wave is large enough. Under certain conditions, these resonances can overlap and thus make the ion motion chaotic. In this process, the plasma can be heated without the limitation of cyclotron resonant condition. Taking into account of a spectrum of waves, the stochastic condition can decrease largely. In addition, the preferential heating can be found in the perpendicular direction.

The reactions of cyclohexenephosphonic acid (C6H9PO3H2) and 3-(2-pyridyl)pyrazole (2-pyPzH) with copper(II) chloride and copper(II) bromide affords a 1-D compound [Cu(2-pyPz)Cl] (1) and a decanuclear [Cu10(OH)4(C6H9PO3)6(2-pyPz)4] (2) cage complex. In 1, adjacent copper ions are bridged by two 2-pyPz ligands into dimers, which are further linked by Cl− into a ladder-like chain. Compound 2 has a decanuclear cage structure, the overall cage can be viewed as composed of two Cu4(OH)2(2-pyPz)2 wings that are bridged by a central Cu2P2O6 rim. Variable-temperature magnetic susceptibility studies indicate that both compounds show antiferromagnetic interactions between copper centers.

The reaction of cyclohexenephosphonic acid (C6H9PO3H2) and 3-(2-pyridyl)pyrazole (2-pyPzH) with copper(II) chloride and copper(II) bromide affords a one-dimensional compound [Cu(2-pyPz)Cl] (1) and a decanuclear [Cu10(OH)4(C6H9PO3)6(2-pyPz)4] (2) cage complex. In 1, adjacent copper ions are bridged by two 2-pyPz ligands into dimers, which are further linked by Cl- into a ladder-like chain. Compound 2 has a decanuclear cage structure, the overall cage can be viewed as composed of two Cu4(OH)2(2-pyPz)2 wings that are bridged by a central Cu2P2O6 rim. Variable-temperature magnetic susceptibility studies indicate that both compounds show antiferromagnetic interactions between copper centers.

A ray-tracing method is developed to evaluate the wave growth/damping and specifically propagation trajectories of the magnetospherically reflected Whistler-mode waves. The methodology is valid for weak wave growth/damping when plasma is comprised of a cold electron population and a hot electron population, together with background neutralizing ions, e.g. protons. The effect of anisotropic thermal electrons on the propagation of Whistler-mode waves is studied in detail. Numerical results are obtained for a realistic spatial variation model of plasma population, including the cold electron density distribution, and the thermal electron density and temperature distribution. It is found that, analogous to the case of the typical cold plasma approximation, the overall ray path of Whistler-mode waves is insensitive to the thermal electron density and temperature anisotropy, and the ray path reflects where wave frequency is below or comparable to the local lower hybrid resonance frequency flhr. However, the wave growth is expected to be influenced by the thermal electron population. The results present a first detailed verification for the validity of the typical cold plasma approximation for the propagation of Whistler-mode waves and may account for the observation that the Whistler-mode waves tend to propagate on a particular magnetic shell L where the wave frequency is comparable to flhr.

The characteristics of magnetohydrodynamic fast wave propagation in the solar stratified atmosphere are studied by the ray tracing method. The propagation behaviour of the wavefronts is described in detail. A magnetic field incorporating the characteristics field spreading expected in flux tubes is used, which represents the main feature of an active region. Partly ionization is considered beside the stratified solar atmosphere consisting chromosphere, transition region and corona. The study may explain the characteristics in observations of Moreton and extra-ultraviolet image telescope (EIT) waves. The wavefront incurred by the disturbance initialized at the base of the transition region propagates fast initially due to strong magnetic field, and it slows down when arriving beyond the region of flux-tube. Meanwhile, the wave propagates in the corona with a more consistent speed, as seen in the observation of EIT waves. The speeds and propagated characteristics in chromosphere and corona of the wavefronts are in agreement with those observed in Hα Moreton and EIT waves, respectively.

The left-hand superluminous electromagnetic waves, L-O mode and L-X mode, can be excited and observed in the auroral cavity of the Earth during the magnetic storms. The two modes can propagate into outer radiation zone and encounter enhanced resonant interactions with the trapped energetic electrons over a wide range of magnetosphere. A current first-order resonant model is extended to evaluate the stochastic acceleration of electrons by the L-O mode and L-X mode at the higher-order resonance. Similar to the first-order resonance, L-O mode can produce significant acceleration of electrons at the higher harmonic resonances over a wide range of wave normal angles and spatial regions. However, the higher harmonic resonance's contribution for significant electron acceleration by L-X mode is less than that of the first order resonance, with the requirement of higher minimum energies, e.g., -1 MeV in the outer radiation belt. This indicates that L-O mode may be one of the efficient mechanisms for the stochastic acceleration of electrons within the outer radiation zone.

The resonant acceleration of electrons by the superluminous R-X mode is evaluated in the high density plasma region of Earth, specifically around the geostationary orbit. The corresponding resonant frequency range together with the harmonic N required for producing a significant acceleration is studied in detail. It is found that the stochastic acceleration is basically controlled by the harmonic N and a dimensionless parameter α = |Ωe2|/ωpe2 (where |Ωe| and ωpe are the electron gyrofrequency and plasma frequency respectively). For α = 0.1 (around the geostationary orbit), there are not gyroresonances occurring between electrons and right-hand extraordinary-mode electromagnetic waves until higher harmonics N≥4; while for α = 0.5, the gyroresonance begins at N = 2. Substantial acceleration of electrons by the right-hand extraordinary mode is possible for those higher harmonic (N>1) resonances over a wide range of wave normal angles θ. This indicates that higher harmonic resonance can play an important role on the electron acceleration in the high density plasma region (α

An extended relativistic model is developed to evaluate the superluminous R–X-mode resonance especially the second-order and third-order resonances with electrons in the Earth's magnetosphere. The potential for stochastic electron acceleration driven by the R–X mode is determined by the dispersive properties of the R–X mode and specifically the resonant harmonic N. In contrast to the limited acceleration at the first harmonic (N = 1) resonance, for the higher harmonic (N>1) resonances, the R–X mode is capable of accelerating electrons from ~10 keV to ~ MeV energies, over a wide range of wave normal angles, in spatial regions extending from the auroral cavity to the latitude (>30 degrees) outer radiation belt. This indicates that higher-order resonance is essentially important for the electron acceleration for the oblique wave propagation.

A 2 1/2-dimensional electromagnetic particle-in-cell (PIC) simulation code is used to investigate the electron acceleration in collisionless magnetic reconnection. The results show that the electrons are accelerated in the diffusion region near the X point, and the acceleration process can be roughly divided into two procedures: firstly the electrons are accelerated in the z direction due to the electric field in the negative z direction. Then the electrons gyrate surrounding the magnetic field with the action of the Lorentz force, through this procedure the electrons reach higher velocity in the x direction and then flow out of the diffusion region. After being accelerated away from the diffusion region, part of electrons is trapped near the O point, and the other part of electrons flows into plasma sheet boundary layer along the magnetic field.

A 2½-dimensional electromagnetic particle-in-cell (PIC) simulation code is used to investigate the wave phenomena in the plasma sheet of collisionless magnetic reconnection. The results show that these waves have the following characteristics: they are right-hand circularity polarized, with propagation direction nearly parallel to local magnetic field, and frequency between 0.07 and 0.17 times of local electron cyclotron frequency. Therefore we conclude that such waves are Whistler waves, and their possible excitation mechanisms are also discussed.

Using two-dimensional full particle simulation, the process of magnetic reconnection in collisionless plasma is investigated and the velocity distributions of ions and electrons in various districts are obtained. As shown by the results of calculation, the Hall current produced by the different characters of electrons and ions in the diffusion region gives rise to a quadrupolar distribution of the y-component of the magnetic field, By. The velocity distributions of ions and electrons deviate from the initial Maxwell distributions, and exhibit nonlocal multiple distributions. At the same time, the electric field generated by the magnetic reconnection leads to the acceleration and heating of the electrons in the vicinity of the X-point. Hence a high-energy tail is formed in the energy spectral distribution of electrons.

One-dimensional particle-in-cell simulations are performed to investigate the nonlinear evolution of electromagnetic instabilities excited by the electron temperature anisotropy in homogeneous plasmas with different parameters. The results show that the electron temperature anisotropy can excite the two right-hand electromagnetic instabilities, one has the frequency higher than Ωe, the other is the whistler instability with larger amplitude, and its frequency is below Ωe. Their dispersion relations are consistent with the prediction from the cold plasma theory. In the initial growth stage (prediction from linear theory), the frequency of the dominant mode (the mode whose amplitude is large enough) of the whistler wave almost does not change, but in the saturation stage the situation is different. In the case that the ratio of electron plasma frequency to cyclotron frequency is larger than 1, the frequency of the dominant mode of the whistler wave drifts from high to low continuously. However, for the case of the ratio smaller than 1, besides the original dominant mode of the whistler wave whose frequency is about 2.6ωe, another dominant mode whose frequency is about 1.55ωe also begins to be excited at definite time, and its amplitude increases with time until it exceeds the original dominant mode.

The process of magnetic reconnection in anisotropic plasmas is studied numerically using a 2-dimensional, 3-component hybrid simulation. The results of the calculation show that, when the plasma pressure in the direction perpendicular to magnetic field is larger than that in the parallel direction (e.g. P ⊥ P ‖ = 1.5 ), instability may greatly increase, speeding up the rate of reconnection. When P⊥ is smaller than P‖, (e.g., when P ⊥ P ‖ = 0.6 ), fire hose instability appears, which will restrain the tearing mode instability and the process of magnetic reconnection.