0604号强热带风暴碧利斯对云南的影响及维持机制

应用MICAPS资料及FY-2C卫星云图,通过天气分析与诊断分析,探讨了0604号强热带风暴碧利斯路径西偏南的原因,对造成云南的暴雨过程进行了分析并研究了这次登陆强热带风暴长久维持不消的物理机制。结果表明:黄海副高南落加强西伸与大陆高压合并加强,高压南侧东北风的牵引作用,是"碧利斯"路径西偏南的主要原因;"碧利斯"造成的云南强降水落区分布在热带低压倒槽前东北风急流区内水汽辐合中心区域,并且与700hPa湿Q矢量辐合区对应较好,热带低压影响期间,大气曾具有湿中性垂直运动结构,具备有利于暴雨系统发展的环境条件;"碧利斯"登陆后长时间和一支深厚的西南急流保持联结,是其长久维持不消的主要因素。西南季风云系卷入热带低压,增强了热带低压的水汽和能量输入,是热带低压得以长久维持并造成云南强降水的另一重要原因。南亚高压在热带低压活动期间增强,高层辐散场的增强,低层辐合、高层辐散的结构,与西南急流相联系的垂直正涡度的维持,有利于热带低压的维持,登陆后的热带低压有向高空强辐散区方向移动的趋势。

Effect of itopride, a new prokinetic, in patients with mild GERD: A pilot study

AIM： Itopride is a newly developed prokinetic agent, which enhances gastric motility through both antidopaminergic and anti-acetylcholinesterasic actions. The importance of esophageal motor dysfunction in the pathogenesis of gastro-esophageal reflux disease （GERD） makes it interesting to examine the effect of itopride on esophageal acid exposure.METHODS： The effect of itopride on esophageal acid reflux variables for 24 h was studied in 26 patients with GERD symptoms, pre-entry total acid exposure time （pH〈4） of more than 5% and mild esophagitis （SavaryMiller grades I, II） proven by endoscopy. Ambulatory 24hpH-metry and symptom assessment were performed after treatments with 150 or 300 mg itopride thrice a day （t.i.d.） for 30 d in random order, using an open label method.For evaluating the safety of itopride, blood biochemical laboratory test was performed and the serum prolactin level was also examined before and after treatment.RESULTS： Total symptom score was significantly decreased after treatment in 150- or 300-mg group. Itopride 300 mg was significantly effective than 150 mg on decreasing the total per cent time with pH〈4, total time with pH〈4 and DeMeester score. No serious adverse effects were observed with administration of itopride in both groups.CONCLUSION： Itopride 100 mg t.i.d, is effective on decreasing pathologic reflux in patient with GERD and therefore it has the potential to be effective in the treatment of this disease.

Dynamic Visualization Approach of the Multiphase Flow Using Electrical Capacitance Tomography

Identifying the flow patterns is vital for understanding the complicated physical mechanisms in multiphase flows.For this purpose,electrical capacitance tomography(ECT) technique is considered as a promising visualization method for the flow pattern identification,in which image reconstruction algorithms play an important role.In this paper,a generalized dynamic reconstruction model,which integrates ECT measurement information and physical evolution information of the objects of interest,was presented.A generalized objective functional that simultaneously considers the spatial constraints,temporal constraints and dynamic evolution information of the objects of interest was proposed.Numerical simulations and experiments were implemented to evaluate the feasibility and efficiency of the proposed algorithm.For the cases considered in this paper,the proposed algorithm can well reconstruct the flow patterns,and the quality of the reconstructed images is improved,which indicates that the proposed algorithm is competent to reconstruct the flow patterns in the visualization of multiphase flows.

Mechanism of Downcutting Erosion of Debris Flow over a Movable Bed

The phenomenon of debris flow is intermediate between mass movement and solid transport. Flows can be sudden, severe and destructive. Understanding debris flow erosion processes is the key to providing geomorphic explanations, but progress has been limited because the physical-mechanical properties, movement laws and erosion characteristics are different from those of sediment-laden flow. Using infinite slope theory, this research examines the process and mechanism of downcutting erosion over a moveable bed in a viscous debris flow gully. It focuses specifically on the scour depth and the critical slope for viscous debris flow,and formulas for both calculations are presented.Both scour depth and the critical conditions of downcutting erosion are related to debris flow properties(sand volume concentration and flow depth) and gully properties(longitudinal slope,viscous and internal friction angle of gully materials,and coefficient of kinetic friction). In addition, a series of flume experiments was carried out to characterize the scouring process of debris flows with different properties. The calculated values agreed well with the experimental data. These theoretical formulas are reasonable, and using infinite slope theory to analyze down cutting erosion from viscous debris flow is feasible.

Noise Shielding Using Acoustic Metamaterials

We exploit theoretically a class of rectangular cylindrical devices for noise shielding by using acoustic metamateriais. The function of noise shielding is justified by both the far-field and near-field full-wave simulations based on the finite element method. The enlargement of equivalent acoustic scattering cross sections is revealed to be the physical mechanism for this function. This work makes it possible to design a window with both noise shielding and air flow.

Based on the Incentive Mechanism of Enterprise Reverse Logistics Research Literature Review

In recent years, along with the people environmental protection consciousness enhancement and the concept of circular economy enterprises to implement reverse logistics is imperative. In recent years, based on the incentive mechanism of reverse logistics literature has gradually emerged. In this paper, the concept of reverse logistics are introduced in detail, and compares the forward logistics and reverse logistics, analyzes the driving factor for the formation of reverse logistics, from the Angle of the government and the enterprise two introduces the related literature, the incentive mechanism on the basis of the summary, summarized the problems of enterprise reverse, government incentives for enterprises is discussed the importance of reverse logistics, based on the existing research results in recent years to sum up, the paper further research are pointed out.

Physical and numerical investigation on transient cavitating flows

The objective of this paper is to investigate transient cavitating flows around a hydrofoil via combined physical and numerical studies. The aims are to 1) investigate the periodic formation, breakup, shedding, and collapse of the sheet/cloud cavities, 2) provide a better insight in the physical mechanism that governs the dynamics and structures of the sheet/cloud cavitation, 3) quantify the influence of cavitation on the surrounding flow structures. Results are presented for a Clark-Y hydrofoil fixed at an angle of attack of a=8° at a moderate Reynolds number, Re=7×105 , for sheet/cloud cavitating conditions. The experimental studies were conducted in a cavitation tunnel at Beijing Institute of Technology, China. The numerical simulations are performed by solving the incompressible, multiphase unsteady Reynolds-averaged Navier-Stokes (URANS) equations via the commercial code CFX using a transport equation-based cavitation model; a filter-based density corrected model (FBDCM) is used to regulate the turbulent eddy viscosity in both the cavitation regions near the foil and in the wake. The results show that numerical predictions are capable of capturing the initiation of the cavity, growth toward the trailing edge, and subsequent shedding in accordance with the quantitative features observed in the experiment. Regarding vapor shedding in the cavitating flow around the three-dimensional foil, it is primarily attributed to the effect of the re-entrant flow, which is formed due to the strong adverse pressure gradient. The results show strong correlation between the cavity and vorticity structures, demonstrating that the inception, growth, shedding, and collapse of sheet/cloud cavities are important mechanisms for vorticity production and modification.

Copper/cuprous sulfide electrode: preparation and performance

Cuprous sulfide （Cu2S） is a direct band-gap p-type semiconductor with excellent ionic/electronic hybrid conductivity. Alt- hough Cu/Cu2S/sulfide or polysulfide system is adopted as counter electrode of quantum-dots-sensitized solar cells （QDSSC）, the electrode process is seldom reported. Here, the electrochemical growth of Cu2S film on a copper （Cu） surface, the redox behaviors of sulfide and polysulfide, and the all-in-solid charge-transfer properties of Cu2S film are investigated. It is clarified that the copper electrode simultaneously undergoes an activated process, a membrane growth process, and a redox phase transformation process. The solid charge-transfer capability of CuzS is quantified with a high exchange-current density of 2.27 A/cm2, which elucidates that the Cu/CuzS electrode is a qualified material for counter electrodes of QDSSC. These results aid understanding of the physicochemical mechanism of QDSSC with a polysulfide electrolyte and Cu/Cu2S counter electrode.