人类胁迫对松嫩平原土壤盐渍化的灰色关联分析

在广泛搜集资料和实地土壤采样调查的基础上,系统分析人为干扰下松嫩平原水盐运动规律及土壤盐渍化过程。利用灰色关联分析方法对该区50年的资料进行定量分析,探讨人为因素引起的松嫩平原水土环境的空间结构变化与土壤盐渍化的耦合关系。研究结果表明植被退化和流域内流化是松嫩平原盐渍化形成与演化的直接原因;短时期内人为因素对土壤盐渍化面积变化影响显著,其贡献率大于气候因子变化对盐渍化面积的影响。

Seasonal and intraseasonal variations of the surface Taiwan Warm Current

To study seasonal and intraseasonal variations of the Taiwan Warm Current (TWC) in detail,Rotated Empirical Orthogonal Function (REOF) and Extended Associate Pattern Analysis (EAPA) are jointly adopted with daily sea surface salinity (SSS), sea surface temperature (SST) and sea surface height (SSH)datasets covering 1126 days from American Navy Experimental Real-Time East Asian Seas Ocean Nowcast System in the present paper. Results show that the first and second REOFs of SST in the southern East China Sea(SECS) account for 50,8% and 39.8% of the total variance. The surface TWC contains persistent (multi-year mean), seasonal and intraseasonal components. The persistent one mainly inosculates with the Kuroshio but the seasonal and intraseasonal ones are usually active only on the continental shelf. Its persistent component is produced by inertial flow of the Kuroshio, however its seasonal and intraseasonal ones seems coming from seasonal and intraseasonal oscillations of monsoon force. The seasonal one reaches its maximum in late summer,lasting about four months and the intraseasonal one takes place at any seasons, lasting more than 40 days.

The Ejffect of Vertical Internal Baffles on Fluidization Hydrodynamics and Grain Drying Characteristics

The effect of vertical internal baffles on the particle mixing and graindrying characteristics in a batch fluidized bed column is investigated. Experimental work wascarried out in a 3m high rectangular fluidized bed dryer of cross sectional area of 0.15 m x 0.61 mat different operating conditions using paddy, a group D particle, as the fluidizing material. Theresults of the study showed that the fluidized bed dryer system with vertical internal baffles gavebetter particle mixing effect in the bed of particles than that without vertical internal baffles.This is due to the fact that the vertical internal baffle act as gas bubble breakers by breaking upthe large gas bubbles into smaller ones. The smaller bubbles cause a more vigorous mixing in the bedof particles before finally erupting at the bed surface. This improves the contacting efficiencyand enhanced the heat and mass transfer of the fluidized bed system. Thus a higher drying rate wasobtained in the falling rate period because the higher contacting efficiency increases theevaporation rate at the particle surface. However, the drying rate in the diffusion region showslittle improvement because the moisture diffusivity does not depend on the contacting efficiency.The fluidized bed dryer with vertical internal baffles could therefore be used in the initial rapiddrying stage in a two stage drying strategy for paddy. The insertion of vertical internal bafflesinto a fluidized bed system improves the processing of Group D particles in a fluidized bed systemespecially if the system is large in scale.

Numerical analysis on forced convection enhancement in an annulus using porous ribs and nanoparticle addition to base fluid

Miniaturization of electronic equipment has forced researchers to devise more effective methods for dissipating the generated heat in these devices.In this study,two methods,including porous media inserting and adding nanoparticles to the base fluid,are used to improve heat transfer in an annulus heated on both walls.To study porous media insert,porous ribs are used on the outer and inner walls independently.The results show that when porous ribs are placed on the outer wall,although the heat transfer enhances,the pressure drop increment is so considerable that performance number (the ratio of heat transfer enhancement pressure increment,PN) is less than unity for all porous rib heights and porous media permeabilities that are studied.On the other hand,the PN of cases where porous ribs were placed on the inner wall depends on the Darcy number (Da).For example,for ribs with Da=0.1 and Da=0.0001,the maximum performance number,PN=4,occurs at the porous ribs height to hydraulic diameter ratios H/Dh=1 and H/Dh=0.25.Under these conditions,heat transfer is enhanced by two orders of magnitude.It is found that adding 5% nanoparticles to the base fluid in the two aforementioned cases improves the Nusselt number and PN by 10%–40%.

Prospective,randomized,and active controlled study of the efficacy of alginic acid and antacid in the treatment of patients with endoscopy-negative reflux disease

AIM： To assess the efficacy and safety of a compound containing alginic acid plus antacid （Topaal） compared to equal-strength antacid （Nacid） in patients with endoscopy-negative reflux disease （ENRD）. METHODS： A total of 121 patients with ENRD were randomized to receive Topaal （65 patients） or Nacid （56 patients） for 6 weeks, with a consultation every 3 weeks. The primary end-point assessment was the change in the severity of heartburn as evaluated using a visual analog scale （VAS） at 6 weeks. The secondary end-point assessments were the VAS at 3 weeks, the change of frequency of the reflux symptom, the change of quality of life and the adverse effects. RESULTS： Demographics of randomized subjects in each treatment group were comparable except that the Topaal group included more males. The baseline characteristics between the groups were similar. After 6 weeks of treatment, the reduction of VAS of heartburn was more prominent in the Topaal group （-6.29 cm vs -4.11 cm）. At the 3m week, Topaal group showed greater reduction of VAS for heartburn （P= 0.0016）, regurgitation （P=0.0006）, vomiting （P=0.0373）, and belching （P〈0.0001）. The patients of the Topaal group had lower frequency of heartburn （P=0.0015） and pain （P= 0.0163） at the end of the 6-week treatment period. From the doctor＇s point of view, the Topaal group also showed significant reduction in the severity of heartburn （P= 0.0020）, regurgitation （P=0.0081）, vomiting （P= 0.0182）, and belching （P= 0.0018） at the end of the treatment. The improvement of the quality of life was more remarkable in the Topaal group at the end of the 6-week treatment period （P〈 0.0001）. For the adverse effect, there was no difference in both the groups. CONCLUSION： Topaal is more effective than Nacid for the treatment of symptoms presented by patients with ENRD.

Sub seasonal variations of weak stratospheric polar vortex in December and its impact on Eurasian air temperature

Weak stratospheric polar vortex(WPV)events during winter months were investigated.WPV events were identified as being weakest in December,accompanied by the most dramatic increase in geopotential height over the polar region.After the onset of a December WPV event,the dynamic processes influencing Eurasian temperature can be split into two separate periods.Period I(lag of 0-25 days)is referred to as the stratosphere-troposphere interactions period,as it is mainly characterized by stratospheric signals propagating downwards.In Period I,a stratospheric negative Northern Annular Mode(NAM)pattern associated with the WPV propagates downwards,inducing a negative NAM in the troposphere.The anomalous low centers over the Mediterranean and North Pacific bring cold advection to northern Eurasia,resulting in a north-cold-south-warm dipole pattern over Eurasia.The zero line between negative and positive temperature anomalies moves southwards during days 5-20.Stratospheric cold anomalies at midlatitudes propagate downwards to high latitudes in the troposphere and contribute to the dipole structure.During PeriodⅡ(lag of 25-40 days),as downward signals from the stratosphere have vanished,the dynamic processes mainly take place within the troposphere.Specifically,a wave train is initiated from the North Atlantic region to northern Europe.The propagation of wave activity flux intensifies a cyclonic anomaly over northern Europe,which brings cold advection to Scandinavia and warm advection to central Asia.Therefore,a northwest-cold-southeast-warm dipole structure occupies Eurasia and migrates southeastwards during this period.

Pathways of intraseasonal Kelvin waves in the Indonesian Throughflow regions derived from satellite altimeter observation

The gridded sea level anomaly（SLA） data-set provided by AVISO is used to track the propagation of intraseasonal Kelvin waves in the Indonesian Throughflow（ITF） region. The large root mean square of intraseasonal SLA along the Sumatra and Java coast is closely related to the propagation of intraseasonal Kelvin waves that derive from the equatorial Indian Ocean. These Kelvin waves are further found to propagate following different pathways at the Lombok Strait. Pathway A propagates eastward throughout the Sumba Strait and Savu Sea to reach the Ombai Strait. Pathway B penetrates into Lombok and propagates northward to reach the Makassar Strait. Pathway C propagates southeastward along the southwest coast of the Sumba Island. The equatorial Kelvin waves take around 15 days to travel from the equatorial Indian Ocean to Lombok Strait, and around 5 days to penetrate into the Makassar and Ombai straits. The Kelvin wave-induced SLA persists in the ITF region for an additional 5 days and then diminishes subsequently. The phase speeds of these intraseasonal Kelvin waves along Pathways A, B, and C are 1.91–2.86, 1.69, and 1.96 m s^-1,respectively—in agreement with the first two baroclinic modes of Kelvin waves.

Topological Structure and Topological Tensor Current of Gauss-Bonnet-Chern Theorem

We offer an intrinsic theoretical framework to reveal the inner relationships among three theories for Euler characteristic number, including Gauss Bonnet-Chern theorem, Hop-Poincaré theorem and Morse theory. Moreover, we consider the Gauss Bonnet-Chern （GBC） form imbedded in arbitrary higher-dimensional manifold, which suggests a Hodge dual tensor current. We show the brane structure inherent in the GBC tensor current and obtain the generalized Nambu action for the multi branes with quantized topological charge.

Simulation of the mixing process in a straight tube with sudden changed cross-section

In this work, we revised the expression of mixing intensity to describe the mixing output through a cross section in a flow system by considering heterogeneity of flow field, and carefully investigated the mixing process along a straight tube with expanding/contracting cross section by simulation method. The simulation results show that a sudden expansion of cross section has remarkable mixing intensification effect within a limited period(on the sub-second scale) or tube-length(on the millimeter scale), corresponding to the generation of considerable local vortices determined by both the flow capacity and the ratio of cross section change; a sudden contraction of cross section has instantaneous but weak mixing intensification effect; through introducing a local expansion structure with proper length, as the combination of sudden expansion and sudden contraction, their mixing intensification effects could be superposed. Besides, the rationality and importance are experimentally verified to explore the time profile of mixing intensity and carry out the vortex analysis by simulation for enhancing the selectivity of a complicated reaction system. These progresses may lead to more meaningful quantitative description of mixing process in a flow microreactor for some specific chemical processes.

Simulation of the western North Pacific subtropical high in El Ni?o decaying summers by CMIP5 AGCMs

The performances of CMIP5 atmospheric general circulation models （AGCMs） in simulating the western North Pacific subtropical high （WNPSH） in El Nino decaying summers are examined in this study. Results show that most models can reproduce the spatial pattern of both climatological and anomalous circulation associated with the WNPSH in El Nino decaying summers. Most CMIP5 AGCMs can capture the westward shift of the WNPSH in El Nino decaying summers compared with the climatological location. With respect to the sub-seasonal variation of the WNPSH, the performances of these AGCMs in reproducing the northward jump of the WNPSH are better than simulating the eastward retreat of the WNPSH from July to August. Twenty-one out of twenty-two （20 out of 22） models can reasonably reproduce the northward jump of the WNPSH in El Nino decaying summers （climatology）, while only 7 out of 22 （8 out of 22） AGCMs can reasonably reproduce the eastward retreat of the WNPSH in El Nino decaying summers （climatology）. In addition, there is a close connection between the climatological WNPSH location bias and that in El Nino decaying summers.

Ankaferd hemostat in the management of gastrointestinal hemorrhages

Gastrointestinal (GI) bleeding refers to any hemorrhage ascribed to the pathologies of the gastrointestinal tract,extending from the mouth to the anal canal.Despite the recent improvements in the endoscopic,hemostatic and adjuvant pharmacologic techniques,the reported mortality is still around 5%-10% for peptic ulcer bleeding and about 15%-20% for variceal hemorrhages.Although endoscopic management reduces the rates of re-bleeding,surgery,and mortality in active bleeding;early recurrence ratios still occur in around 20% of the cases even with effective initial hemostatic measures.In this quest for an alternative pro-hemostatic agent for the management of GI bleedings,Ankaferd blood stopper (ABS) offers a successful candidate,specifically for "difficult-to-manage" situations as evidenced by data presented in several studies.ABS is a standardized mixture of the plants Thymus vulgaris,Glycyrrhiza glabra,Vitis vinifera,Alpinia officinarum,and Urtica dioica.It is effective in both bleeding individuals with normal hemostatic parameters and in patients with deficient primary and/or secondary hemostasis.ABS also modulates the cellular apoptotic responses to hemorrhagic stress,as well as hemostatic hemodynamic activity.Through its effects on the endothelium,blood cells,angiogenesis,cellular proliferation,vascular dynamics,and wound healing,ABS is now becoming an effective alternative hemostatic medicine for gastrointestinal bleedings that are resistant to conventional anti-hemorrhagic measurements.The aim of this review is to outline current literature experience suggesting the place of ABS in the management of GI bleeding,and potential future controlled trials in this complicated field.

Simplified Correlation Equations of Heat Transfer Coefficient during Phase Change for Flow inside Tubes

In this work, the easy to use, simple and direct equations were formulated and tested. These equations can be used to calculate the mean values of the heat transfer coefficients of inside tube flow during phase change. Analytical and experimental methods were used to correlate these equations. Two different forms were used, one for evaporation case and the other for condensation case. Carbon dioxide, CO2, was used as case study. Correlated values of the mean heat transfer coefficients （hcor,.） were compared with the experimental results （he^e） and with other published result, a good agreement was noticed. The resulted correlations can be used to simplify the design and performance studies of both condensers and evaporators.

Cooling of Superheated Refrigerants Flowing inside Tubes Filled with Porous Media： Study of Heat Transfer and Pressure Drop, Carbon Dioxide Case Study

In this work an experimental study combined with an analytical investigation for cooling superheated Carbon Dioxide （CO2） gas were carried out. This work is intended to be part of the super critical Gustav Lorentzen refrigeration cycle of CO2. Experimental and analytical works concentrated on heat transfer and pressure drop for single phase flow during gas cooling inside tubes filled with porous media. Analytical empirical correlations were formulated for the coefficient of convectional heat transfer and for the pressure drop. A comparison between experimental results and that obtained by developed correlations were carried out, and a comparison between these results and literature published ones were carried out too. The results of this research showed that for cooling process the proposed correlations were proved to be acceptably accurate for pressure drop with difference from experimental results of 2%, while for convective heat transfer the difference from experimental results reached about 3%. More than 90% agreement with literature results was obtained. This work can enhance the calculations of heat flux and pressure drop of gases flow inside porous media filled tubes, and can help in the design procedure of heat exchangers and cooling processes.

The Research on Optimization of the Multiphase Flow Field of Biogas Plant by Using CFD Software

The inner flow field of a biogas plant can be optimized by agitating the feedstock to be evenly distributed for a rising biogas production rate. A hydraulic agitator can be installed in the digester with outlets far above the bottom. Hydraulic mixing is essential in a solid-liquid two-phase flow process, in which large solid particles can be found at the initial stage and turn to being high-concentration viscous liquid （non-Newtonian fluid）. A 0.75 m3 digester was taken as a case study with CFD （computational fluid dynamics） software. The basic pattern was simulated by using water as the medium and the pattern of pseudo plastic fluid state was simulated by the Euler-Euler Model, then the effect of optimized design with bottom inflow and high dispersed outlets could be verified. Viewed from the mixing effects, the velocity of 0.6 m/s is better than l m/s for water medium, while 1 m/s better than 0.6 m/s for pseudo plastic fluid medium.

Propagation of Weak Pressure Waves against Two Parallel Subsonic Streams

In this paper, the characteristics of a pressure wave propagating against two parallel subsonic streams in a constant-area straight duct are investigated by one-dimensional analysis, two-dimensional numerical simulation, and experiments. Computations have been carried out by the two-dimensional Euler Equations using the Chakravarthy-Osher-type TVD scheme. Optical observations by the schlieren method as well as wall pressure measurements have been performed to clarify both the structure and the propagation velocity of pressure waves. The results show that the pressure wave propagating against the streams changes into a bifurcated pressure wave and the bifurcation occurs in the low speed streams. It is also found that the propagation velocity of the pressure wave obtained by the analysis and computation agrees well with the present experimental data.

Analysis of an improved workflow of endoscope reprocessing for bedside endoscopic diagnosis and treatment on COVID-19 patients

Severe cases infected with the coronavirus disease 2019(COVID-19),named by the World Health Organization(WHO)on Feb.11,2020,tend to present a hypercatabolic state because of severe systemic consumption,and are susceptible to stress ulcers and even life-threatening gastrointestinal bleeding.Endoscopic diagnosis and treatment constitute an irreplaceable part in the handling of severe COVID-19 cases.Endoscopes,as reusable precision instruments with complicated structures,require more techniques than other medical devices in cleaning,disinfection,sterilization,and other reprocessing procedures.From 2016 to 2019,health care-acquired infection caused by improper endoscope reprocessing has always been among the top 5 on the list of top 10 health technology hazards issued by the Emergency Care Research Institute.Considering the highly infective nature of COVID-19 and the potential aerosol contamination therefrom,it is of pivotal significance to ensure that endoscopes are strictly reprocessed between uses.In accordance with the national standard"Regulation for Cleaning and Disinfection Technique of Flexible Endoscope(WS507-2016),"we improved the workflow of endoscope reprocessing including the selection of chemicals in an effort to ensure quality control throughout the clinical management towards COVID-19 patients.Based on the experience we attained from the 12 severe COVID-19 cases in our hospital who underwent endoscopy 23 times in total,the article provides an improved version of endoscopic reprocessing guidelines for bedside endoscopic diagnosis and treatment on COVID-19 patients for reference.

Reform and opening up in the area of circulation:a retrospect

China＇s reform and opening up in the area of circulation are an important component of the establishment of a socialist mgrket economy system. Prior to reform and opening up, this area had long been characterized by a high level of centralization, closedness and segmentation. The domestic market was isolated from the overseas market and internal trade from foreign trade, and each had its own management system and policy environment. The thirty years of reform and opening up, however, have put a new face on the institutional environment of circulation： an open and modern system of circulation has been basically established, an embryonic WTO-consistent business administration system is taking shape, and the extension Of business and trade service ixidustries has facilitated institutional innovation. The main experience of reform is the following： first, taking opening up as the leading principle and making use of opening up to promote reform; second, following an incremental path of dealing with the easier issues before the harder ones, building up while you tear down, and gradual improvement; and third, breaking through the traditional framework of commodity circulation and establishing new business systems that accommodate more service industries. The economic implication of China＇s reform experience is as follows： an export-oriented strategy must inevitably be chosen as the point of entry for reform; there is an inherent linkage between market structure and human capital in the circulation of goods and services; and expanding the circulation of non-material goods is an important basis for institutional innovation.

Enhanced External Counterpulsation Inducing Arterial Hemodynamic Variations and Its Chronic Effect on Endothelial Function

To make clear the precise hemodynamic mechanism underlying the anti-atherogenesis benefit of enhanced external couterpulsation(EECP) treatment, and to investigate the proper role of some important hemodynamic factors during the atherosclerotic progress, a comprehensive study combining long-term animal experiment and numerical solving was conducted in this paper. An experimentally induced hypercholesterolemic porcine model was developed and the chronic EECP intervention was subjected. Basic hemodynamic measurement was performed in vivo, as well as the arterial endothelial samples were extracted for physiological examination. Meanwhile, a numerical model was introduced to solve the complex hemodynamic factors such as WSS and OSI. The results show that EECP treatment resulted in significant increase of the instant levels of arterial WSS, blood pressure, and OSI. During EECP treatment, the instant OSI level of the common carotid arteries over cardiac cycles raised to a mean value of 8.58 ×10-2±2.13 ×10-2. Meanwhile, the chronic intervention of EECP treatment significantly reduced the atherosclerotic lesions in abdominal aortas and the endothelial cellular adherence. The present study suggests that the unique blood flow pattern induced by EECP treatment and the augmentation of WSS level in cardiac cycles may be the most important hemodynamic mechanism that contribute to its anti-atherogenesis effect. And as one of the indices that cause great concern in current hemodynamic study, OSI may not play a key role during the initiation of atherosclerosis.