Search

This paper serves to simulate compressible multi-fluid flows using an energy-splitting method based on the generalized Riemann problem (GRP) solver. The emphasis is put on two-dimensional problems to address the fundamental role of transversal effect in the construction of numerical fluxes, which exhibits the genuine multi-dimensionality of the underlying numerical schemes. In contrast with the popularly-used methods of line which use exact or approximate Riemann solvers, the GRP solver, as the discontinuous version of the Lax–Wendroff method, takes the temporal-spatial coupling process to include the transversal effect. Combined with the energy-splitting technique developed earlier in Lei and Li [24], the resolution of flow fields around material interfaces is improved significantly.

The aim of this study is to determine the accuracy rate of bronchopulmonary dysplasia (BPD) diagnosis and risk factors of short-term poor prognosis for premature infants. This study analyzed the clinical data of 81 premature infants (28 days, and survived >36 weeks (corrected age). Outcome measures included treatments, conditions on the 28th day after birth, oxygen therapy conditions at the 36th week, occurrence of any serious complications during hospital stay. The major risk factors affecting prognosis were ventilation duration, duration of oxygen therapy, application of steroids, hypothyroidism and severity of BPD (all P

The simulation of compressible multi-fluid flows receives increasing attention, thanks to extensive engineering applications, but there are still many bottleneck problems remain unresolved due to the presence of singularities (shocks, material interfaces, vortices and other discontinuities etc) in flows, which arises notorious diffculties in all aspects of theoretical justification, numerical analysis and scientific computation. In contrast with single-fluid problems, the treatment of material interfaces become an extremely controversial issue in terms of numerical modeling and numerical methods besides conventional shocks and rarefaction shocks. In this paper this topic is reaccessed and a family of temporal-spatial coupled high order accurate schemes are introduced. The temporal-spatial coupling distinguishes these schemes from the methods of line (e.g. RK-WENO, RK-DG) and implicitly includes many fundamental properties such as thermodynamical consistency, multi-dimensionality and symplecticity. The generalized Riemann solver is adopted to provide high order accurate numerical fluxes and reflect “true” dynamical processes.

This paper serves to treat boundary conditions numerically with high order accuracy in order to match the two-stage fourth-order finite volume schemes for hyperbolic problems developed in [{\em J. Li and Z. Du, A two-stage fourth order time-accurate discretization {L}ax--{W}endroff type flow solvers, {I}. {H}yperbolic conservation laws, SIAM, J. Sci. Comput., 38 (2016), pp.~A3046--A3069}]. As such, it is significant when capturing small scale structures near physical boundaries. Different from previous contributions in literature, the current approach constructs a fourth order accurate approximation to boundary conditions by only using the Jacobian of the flux function (characteristic information) instead of its successive differentiation leading to tensors of high ranks in the inverse Lax-Wendroff method. Technically, data in several ghost cells are constructed with interpolation so that the interior scheme can be implemented over boundary cells, and theoretical boundary condition has to be modified properly at intermediate stages so as to make the two-stage scheme over boundary cells fully consistent with that over interior cells. This highlights the fact that {\em continuous boundary conditions only match continuous partial differential equations (PDEs), and they must be approximated in a consistent way (even though it could be exactly valued) when the PDEs are discretized.} Several numerical examples are provided to illustrate the performance of the current approach when dealing with general boundary conditions.

This paper develops a new fifth order accurate Hermite WENO (HWENO) reconstruction method for hyperbolic conservation schemes in the framework of the two-stage fourth order accurate temporal discretization in [{\em J. Li and Z. Du, A two-stage fourth order time-accurate discretization {L}ax--{W}endroff type flow solvers, {I}. {H}yperbolic conservation laws, SIAM, J. Sci. Comput., 38 (2016), pp.~A3046--A3069}]. Instead of computing the first moment of the solution additionally in the conventional HWENO or DG approach, we can directly take the {\em interface values}, which are already available in the numerical flux construction using the generalized Riemann problem (GRP) solver, to approximate the first moment. The resulting scheme is fourth order temporal accurate by only invoking the HWENO reconstruction twice so that it becomes more compact. Numerical experiments show that such compactness makes significant impact on the resolution of nonlinear waves.

The aim of this study was to observe the dynamic changes of serum brain-derived neurotrophic factor (BDNF), S-100B, and Tau proteins levels in full-term newborns with hypoxic–ischemic encephalopathy (HIE) and to discuss their significance in brain damage. Serum samples of 28 full-term newborns diagnosed with HIE and 20 controls were obtained in the first 24 h of life. Another serum samples were also taken, respectively, at 3 and 7 days of life in HIE group. The concentrations of BDNF, S-100B, and Tau proteins were measured by the enzyme-linked immunosorbent assay method. Mean concentrations of BDNF, S-100B, and Tau proteins among different time period and in different grades of HIE group were calculated and compared. Compared with the control group, serum BDNF and proteins S-100B levels in HIE group were significantly elevated in 24 h after birth (P < 0.05) and their concentrations were also significantly higher among patients with mod-severe HIE compared to those with mild HIE at 24 h and 7 days after asphyxia (P < 0.05). Regardless of whether mod-severe HIE or mild HIE, there were no significant difference of serum BDNF and proteins S-100B among the three different time periods. There was no difference in Tau protein levels between HIE group and control group, also no difference between mod-severe HIE group and mild HIE group. BDNF and proteins S-100B are up-regulated early in asphyxia neonates with HIE; and the released amount of BDNF and proteins S-100B from nerve center system correlate with the extent of encephalopathy.

In this paper we develop a novel two-stage fourth order time-accurate discretization for time-dependent flow problems, particularly for hyperbolic conservation laws. Different from the classical Runge-Kutta (R-K) temporal discretization for first order Riemann solvers as building blocks, the current approach is solely associated with Lax-Wendroff (L-W) type schemes as the building blocks. As a result, a two-stage procedure can be constructed to achieve a fourth order temporal accuracy, rather than using well-developed four stages for R-K methods. The generalized Riemann problem (GRP) solver is taken as a representative of L-W type schemes for the construction of a two-stage fourth order scheme., 24 pages

To summarize the clinical characteristics of an infant with chronic myelogenous leukemia (CML) and the effects of imatinib on the case.The clinical features of an infant with CML, who was treated with imatinib in the Norman Bethune International Peace Hospital at June 2009, were retrospectively analyzed and the reports in literature were reviewed. The 1-year-old boy suffered from recurrent low-degree fever and pallor. He had a moderate anemia, distended abdomen and marked splenomegaly. Bone marrow aspiration revealed CML in chronic phase)CP). The t (9; 22))q34; q11) could be detected and BCR-ABL (p210) was positive. The boy was diagnosed as CML-CP and treated with imatinib 100 mg per day. There were 10 related papers and more than 100 child CML patients were reported as retrieved from CNKI)from its establishment to August 2014) and Wanfang Database)from its establishment to August 2014) when "Child", " Chronic" and "Leukemia" were used as keywords. And there were 30 related papers including 400 cases from PubMed Database (from its establishment to August 2014) and one detailed report of an infant with CML was retrieved when "childhood" and "chronic myeloid leukemia" "imatinib" were used as keywords. The clinical effects of imatinib in infant CML cases were analyzed and summarized based on the literature.The boy obtained a complete hematologic response (CHR) at the 6th week of diagnosis, a complete cytogenetic response (CCyR) at the 3rd month and a complete molecular response)CMR) at the 12th month without side effect. This boy grows very well and after a 62-month follow-up, his disease was stable. According to the domestic literature, 5 children CML cases aged 6 -12 years were treated with imatinib without side effects and got complete hematologic response (CHR) after 2-month-therapy. The dose, metabolic characteristics and clinical observation of imatinib can be found in foreign literature and imatinib showed good response with good tolerance in children with CML. Imatinib is regarded as the first line drug for children CML. But it may affect the development of the children.The children with CML-CP had a good response to imatinib, but more experience in the treatment of children with CML with iniatinib is needed.

Autonomous car is an important tool for transportation and military in the future, and its precise positioning is the basis of autonomous navigation. Most positioning algorithms based on map-matching for autonomous car make little use of environmental perception information. To solve this problem, a positioning algorithm is proposed in this paper, which is based on map-matching and environmental perception for autonomous car. The algorithm includes macroscopic road matching and microscopic precise positioning. As for macroscopic road matching, the algorithm makes use of computational geometry to match the position of autonomous car to the corresponding road, based on GPS point and map information of the road network. As for microscopic precise positioning, the algorithm makes use of the environmental perception, which is detected by the autonomous car to make precise positioning. Macroscopic road matching provides matching road to microscopic precise positioning, and microscopic precise positioning eliminates gross error produced in macroscopic road matching. Through real car tests, the algorithm can match map quickly, improving the positioning precision with strong real-time.

Partial discharge location is a powerful and useful tool for the maintenance and operation of electrical power distribution cables and has attracted tremendous research and development effort since the 1980's. Questions regarding location estimation and selection of system parameters remain unanswered. In this paper, we give theoretical attention to these questions via the Cramer-Rao lower bound analysis.

The digitized partial discharge (PD) signal recorded at one power cable end consists of a sequence of pulses whose separation time contains information on the relative location of the PD sites. However, noisy PD signals can lead to a large PD site estimation error. The most annoying noise encountered during PD measurements consists primarily of amplitude modulated (AM) radio signals. The performance and the resolution of the wide band PD detection system are critically affected by this noise. This paper describes an adaptive noise mitigating system (ANMS) which is aimed at effectively reducing this noise.

This paper describes a partial discharge propagation model and a location estimate which uses digital signal processing techniques. The model and the estimate are developed for an instrument which is capable of locating partial discharge sites in power cables non-destructively and in situ. Since the model utilizes actual cable response to partial discharge signals, it provides an excellent waveform match between simulations and measurements. The estimator can locate partial discharge sites in noisy environments with an error not exceeding 2 m. Applications of this model to field test data are also discussed. >

The resolution and robustness of a cable PD locating instrument, based on time-domain reflectrometry (TDR), are critically affected by noise present in a field environment. The permanent background noise encountered during field tests has been shown to be mainly due to amplitude modulation (AM) radio signals. This paper describes a self-learning digital filter aimed at mitigating this noise. The filter, in conjunction with a signal averaging routine, has been successfully used to reduce noise and enhance the PD signal obtained from a cable in a field environment. Examples are provided to demonstrate the ability of the filter to significantly improve the signal-to-noise ratio (SNR) and effectively extract PD signals from field recordings. >