Function of large-volume high-pressure apparatus at SECUF

Pressure allows the precise tuning of a fundamental parameter, the interatomic distance, which controls the electronic structure and virtually all interatomic interactions that determine material properties. Hence, pressure tuning is an effective tool in the search for new materials with enhanced properties. To realize pressure tuning on matter, large-volume press （LVP） apparatuses have been widely used not only to synthesize novel materials but also to implement the in situ measurement of physical properties. Herein, we introduce the LVP apparatuses, including belt-type, cubic anvil, and 6-8 type multi-anvil, that will be constructed at the Synergetic Extreme Condition User Facility （SECUF） at Jilin University. Typically, cell volumes of 1000 mm3 can be obtained at 20 GPa in a belt-type apparatus that is significantly larger than that obtained in a 6-8 type multi-anvil apparatus at the same pressure. Furthermore, the in situ measurement of physical prop- erties, including thermological, electrical, and mechanical behaviors, is coupled to these LVP apparatuses. Some typical results of both synthetic experiments and in situ measurements obtained from the LVP apparatuses are also reviewed.

Neutron Diffraction of Large-Volume Samples at High Pressure Using Compact Opposed-Anvil Cells

Neutron diffraction techniques of large-volume samples at high pressure using compact opposed-anvil cells are developed at a reactor neutron source, China＇s Mianyang research reactor. We achieve a high-pressure condition of in situ neutron diffraction by means of a newly designed large-volume opposed-anvil cell. This pressure calibration is based on resistance measurements of bismuth and the neutron diffraction of iron. Pressure calibration experiments are performed at room temperature for a new cell using the tungsten carbide anvils with a tapered angle of 30°, Φ4.5 mm culet diameter and the metal-nonmetal composite gasket with a thickness of 2 mm. Transitions in Bi（Ⅰ–Ⅱ 2.55 GPa, Ⅱ–V 7.7 GPa） are observed at 100 and 300 kN, respectively, by resistance measurements.The pressure measurement results of neutron diffraction are consistent with resistance measurements of bismuth.As a result, pressures up to about 7.7 GPa can routinely and stably be achieved using this apparatus, with the sample volume of 9 mm^3.

Determination of selected semi-volatile organic compounds in water using automated online solid-phase extraction with large-volume injection/gas chromatography/mass spectrometry

A rapid,sensitive,and cost-effective analyticalmethod was developed for the analysis of selected semivolatileorganic compounds in water.The method used anautomated online solid-phase extraction technique coupledwith programmed-temperature vaporization large-volumeinjection gas chromatography/mass spectrometry.Thewater samples were extracted by using a fully automatedmobile rack system based on x-y-z robotic techniquesusing syringes and disposable 96-well extraction plates.The method was validated for the analysis of 30 semivolatileanalytes in drinking water,groundwater,andsurface water.For a sample volume of 10 mL,the linearcalibrations ranged from 0.01 or 0.05 to 2.5μg·L^(-1),and themethod detection limits were less than 0.1μg·L^(-1).For thereagent water samples fortified at 1.0μg·L^(-1)and2.0μg·L^(-1),the obtained mean absolute recoveries were70%-130%with relative standard deviations of less than20%for most analytes.For the drinking water,groundwater,and surface water samples fortified at 1.0μg·L^(-1),theobtained mean absolute recoveries were 50%-130%withrelative standard deviations of less than 20%for mostanalytes.The new method demonstrated three advantages:1)no manipulation except the fortification of surrogatestandards prior to extraction;2)significant cost reductionassociated with sample collection,shipping,storage,andpreparation;and 3)reduced exposure to hazardous solventsand other chemicals.As a result,this new automatedmethod can be used as an effective approach for screeningand/or compliance monitoring of selected semi-volatileorganic compounds in water.

Three-dimensional non-equilibrium modeling of a DC multi-cathode arc plasma torch

In this paper,a three-dimensional non-equilibrium steady arc model is used to investigate the temperature,velocity and electromagnetic field in multi-cathode arc torch,and the formation mechanism of a large-area,uniform and diffused arc plasma is analyzed.The numerical simulation results show that a large volume plasma region can be formed in the central region of the generator during discharge.During this process,the maximum electron temperature appears near the cathode and in the central convergence region,while the maximum heavy particle temperature only appears in the central convergence region.This phenomenon is consistent with the experimental arc images.Near the cathode tip,the arc column is in a contraction state.In the area slightly away from the cathode,the six arc columns begin to join together.In the plasma generator,there is a large-scale current distribution in all directions of X,Y and Z,forming a stable arc plasma with a wide range of diffusion.The calculated electron temperature distribution is in good agreement with the measured electron temperature.The results suggest that the largearea diffused arc plasma in the multi-cathode arc torch is the combined effect of current distribution,convection heat transfer and heat conduction.

Characteristics of Airgun Signals Excited in the Yangtze River from Analysis of Data from Permanent Stations

The Anhui Experiment, a pilot experiment of "Yangtze River Geoscience Project "conducted in October,2015,is a large active-source experiment using airgun sources. It was the first 3-dimensional seismic survey with active sources in the Yangtze River. The sources are airguns in 20 fixed shot points,and the observation system consists mainly of109 permanent stations and 11 wide-angle profiles. Using the data from permanent stations,we investigated the seismic signals generated by airgun sources in the Yangtze River. The results show that the airgun signals are observable in the records from permanent stations to a maximum distance of 300 km. Further analysis on absolute amplitude of airgun signals shows that:( 1) the strength of airgun signals is of the order of10 nm at 50 km away from the source,and then,decreases significantly to less than 1nm at 200 km;( 2) an azimuthal anisotropy is observed in spatial distribution of the strength of airgun signals,which may be related to the geometry of Yangtze River; and( 3) a low ambient noise level is essential for retrieving weak airgun signals from the records,and the high-quality China National Seismic Network and regional networks offer a great opportunity to retrieving airgun signals with amplitude as small as nanometers.

In-situ control of oxygen fugacity for laboratory measurements of electrical conductivity of minerals and rocks in a multi-anvil press

In this paper, a new of oxygen fugaeity controltechnique that can be widely applied to in-situ measurement of the grain interior electrical conductivities of minerals and rocks is presented for high temperature and high pressure. Inside the sample assembly, a metal and corresponding metal oxide form a solid oxygen buffer. The principle of this technique is to randomly monitor and adjust oxygen fugacity in the large-volume multi-anvil press by changing the types of solid oxygen buffer, metal shielding case and electrodes. At a pressure of up to 5.0 GPa and a temperature of up to 1423 K, the electrical conductivities of the dry peridotite are tested under the conditions of different oxygen fugacities. By virtue of this new technique, more and more reasonable and accurate laboratory electrical property data will be successfully obtained under controlled thermodynamic conditions.

Long-term albumin infusion in decompensated cirrhosis:A review of current literature

Decompensated cirrhosis is characterized by chronic inflammation and severe portal hypertension leading to systemic circulatory dysfunction.Albumin infusion has been widely used in decompensated cirrhosis in patients with spontaneous bacterial peritonitis,large-volume paracentesis and hepatorenal syndrome.Emerging data suggest long-term albumin infusion has both oncotic and non-oncotic properties which may improve the clinical outcomes in decompensated cirrhosis patients.We review the current literature on both the established and potential role of albumin,and specifically address the controversies of long-term albumin infusion in decompensated cirrhosis patients.

Attenuation Characteristics of Earthquake Ground Motion for Large Volume Airgun

In order to further deepen the understanding of seismic wave propagation characteristics induced by the large volume airgun source,experimental data from multiple fixed excitation points in Fujian Province were used to obtain the equivalent single excitation high signal-to-noise ratio velocity and displacement records through linear stacking and simulation techniques.Then the peak displacements of different epicentral distances were used to calculate the equivalent magnitude of the airgun source excitation at different fixed excitation points so as to establish the attenuation relationship between equivalent magnitude,epicenter distance and velocity peak.Our results show that:①Within 270 km of epicentral distance,for the large-volume airgun’s single shot,the peak velocity range is about 700-4 nm/s,and the peak displacement range is about 200.0-0.2 nm;②The equivalent magnitude of the P-wave from the airgun source with a total capacity of 8,000 in 3 is 0.181-0.760,and the equivalent magnitude of the S-wave is 0.294-0.832.By contrast,the equivalent magnitude of the P-wave from the airgun source with a total capacity of 12,000 in 3 is 0.533-0.896,and the equivalent magnitude of the S-wave is 0.611-0.946.The S-wave energy is greater than the P-wave energy,and the excitation efficiency varies greatly with different excitation environment;③The peak velocity increases with the equivalent magnitude,and decreases with the epicentral distance.The vertical component of the P-wave peak velocity is the largest among those three components,while the S-wave has the smallest vertical component and similar horizontal components.Hence,our research can provide an important basis for the quantitative judgment of the seismic wave propagation distance using the airgun and the design of the observation system in deep exploration or monitoring with airgun.

The Efficacy Analysis of Transbronchoscopic Large Volume Lung Lavage in Treatment of Pneumoconiosis Complicated with Chronic Obstructive Pulmonary Disease

Objective:To evaluate the efficacy of transbronchoscopic large volume lung lavage in the treatment of pneumoconiosis complicated with chronic obstructive pulmonary disease(COPD).Methods:The clinical data of 80 patients with pneumoconiosis complicated with COPD admitted to our hospital from June 2017 to January 2019 were retrospectively analyzed.40 patients in the control group were treated with conventional drugs and 40 patients in the observation group treated with conventional drugs plus transbronchoscopic large-volume lung lavage.Dyspnea score and healthy quality of life were compared between the two groups.Results:the scores of dyspnea in the observation group were significantly lower than those in the control group at 12,24 and 48 weeks after treatment,and the(SGRQ)scores of George’s respiratory problems questionnaire in the observation group were significantly lower than those in the control group at 12,24 and 48 weeks after treatment.Conclusion:Thetransbronchoscopic large volume of lung lavage has a significant effect on the treatment of pneumoconiosis patients with COPD,which can effectively reduce the degree of dyspnea and improve the quality of life.

衣物类生物检材DNA检验的研究

目的建立对衣物类生物检材STR检验的有效自动提取纯化方法。方法对100例衣物类生物检材用EZ1DNA Investigator试剂盒、EZ1Advanced XL工作站的Large-Volume程序(大体积法)进行提取纯化,AmpFLSTR~Identifiler~Plus荧光STR复合扩增,3500x L型遗传分析仪分析结果。结果 69份检材中检出了单一DNA分型结果,9份检出了混合基因型,22份未检出基因型。结论该方法对衣物类生物检材DNA提取纯化后进行荧光STR检测,可应用于法庭科学实践。

Pathophysiology and Prevention of Paracentesis-induced Circulatory Dysfunction:A Concise Review

Annually,10%of cirrhotic patients with ascites develop refractory ascites for which large-volume paracentesis(LVP)is a frequently used therapeutic procedure.LVP,although a safe method,is associated with circulatory dysfunction in a significant percentage of patients,which is termed para-centesis-induced circulatory dysfunction(PICD).PICD results in faster reaccumulation of ascites,hyponatremia,renal impairment,and shorter survival.PICD is diagnosed through laboratory results,with increases of>50%of baseline plasma renin activity to a value≥4 ng/mL/h on the fifth to sixth day after paracentesis.In this review,we discuss the pathophysi-ology and prevention of PICD.