Source analysis of dissolved heavy metals in the Shaying River Basin,China

Over the years,the Shaying River Basin has experienced frequent instances of river pollution.The presence of numerous critical pollutant discharge enterprises and sewage-treatment plants in the vicinity of the Shaying River has transformed it a major tributary with relatively serious pollution challenge within the upper reaches of Huaihe River Basin.To study the sources of manganese(Mn),chromium(Cr),nickel(Ni),arsenic(As),cadmium(Cd)and lead(Pb)in Shaying River water,123 sets of surface water samples were collected from 41 sampling points across the entire basin during three distinct phases from 2019 to 2020,encompassing normal water period,dry season and wet season.The primary origins of heavy metals in river water were determined by analyzing the heavy metal contents in urban sewage wastewater,industrial sewage wastewater,groundwater,mine water,and the heavy metal contributions from agricultural non-point source pollution.The analytical findings reveal that Mn primarily originates from shallow groundwater used for agricultural irrigation,While Cr mainly is primarily sourced from urban sewage treatment plant effluents,coal washing wastewater,tannery wastewater,and industrial discharge related to metal processing and manufacturing.Ni is mainly contributed by urban sewage treatment plant effluents and industrial wastewater streams associated with machinery manufacturing and metal processing.Cd primarily linked to industrial wastewater,particularly from machinery manufacturing and metal processing facilities,while Pb is predominantly associated with urban sewage treatment plant effluents and wastewater generated in Pb processing and recycling wastewater.These research provides a crucial foundation for addressing the prevention and control of dissolved heavy metals at their sources in the Shaying River.

Crystal structure and negative thermal expansion of solid solution Lu_2W_(3-x)Mo_xO_(12)

A new series of solid solutions Lu2W3-xMoxO12 （0.5≤r≤2.5） were successfully synthesized by the solid-state method. Their crystal structure and negative thermal expansion properties were studied using high-temperature X-ray powder diffraction and the Rietveld method. All samples of rare-earth ttmgstates and molybdates are found to crystallize in the same orthorhombic structure with space group Pnca and show the negative thermal expansion phenomena related to transverse vibration of bridging oxygen atoms in the structure. Thermal expansion coefficients （TEC） of Lu2W3_xMoxO12 are determined as -20.0× 10^-6 K^-1 for x=0.5 and -16.1×10^-6 K^-1 for x=2.5 but -18.6× 10^-6 and -16.9× 10^-6K^-1 for unsubstituted Lu2W3012 and Lu2M03012 in the identical temperature range of 200 to 800℃. High-temperature X-ray diffraction （XRD） data and bond length analysis suggest that the difference between W-O and Mo-O bond is responsible for the change of TECs after the element substitution in this series of solid solutions.

The behavior of cesium adsorption on zirconyl pyrophosphate

Zirconyl pyrophosphate(ZrP_2O_7) was prepared and Cs adsorption behavior was studied.Results show that the distribution coefficient of Cs adsorption on ZrP_2O_7 was about 2800 mL/g.Ion exchange capacity of ZrP_2O_7 was0.35 mmol/g.In dynamic tests,Cs can be separated from other fission products very well by ZrP_2O_7.The ZrP_2O_7was stable both at high temperatures and in high concentration of nitric acid.The Cs adsorption by ZrP_2O_7 is a monolayer and chemical adsorption.

Meta-analysis of the efficacy and safety of rhbnp in the treatment of acute myocardial infarction with heart failure

Objective:Systematic review of the efficacy and safety of neoactivin re-acute myocardial infarction with heart failure.Methods:The computer retrieved CNKI,Wan Fang,Weipu Chinese Science and Technology Periodicals Database(VIP),China Biomedical Literature Database(CBM),Medline,Cochrane Library,and Clinical Trail.Gov collected clinical randomized controlled trials(RCTs)of neoactivin in the treatment of acute myocardial infarction with heart failure from the establishment of the database to December 2019.Data were extracted according to the Jadad scale,disease inclusion and exclusion criteria,and RevMan 5.3 software was used for Meta analysis.Results:A total of 23 RCTs were included,with a total of 2024 patients,including 1012 patients in the control group(conventional treatment with western medicine)and 1012 patients in the test group(on the basis of the control group+neoactivin treatment).Meta analysis results show that:in the total effective rate,the test group was better than the control group,and the difference was statistically significant(OR=4.30,95%CI[3.26,5.67],P<0.00001);In terms of left ventricular ejection fraction,the test group was better than the control group,and the difference was statistically significant(OR=1.58,95%CI[1.27,1.90],P<0.00001).In terms of the left ventricular end-diastolic diameter,the test group was better than the control group,with a statistical difference Significance(OR=-0.91,95%CI[-1.50,-0.33],P=0.002);In terms of stroke volume,the test group was better than the control group,and the difference was statistically significant(OR=1.24,95%CI[0.55,1.94],P=0.0005);In terms of brain natriuretic peptide precursors,the experimental group was better than the control group,the difference was statistically significant(OR=-4.37,95%CI[-6.21,-3.25],P<0.00001);In terms of heart rate,the test group was better than the control group,and the difference was statistically significant(OR=-13.70,95%CI[-14.95,-12.46],P<0.00001);In terms of systolic blood pressure,the test group was better than the control Group,the difference was statistically significant(OR=-12.38,95%CI[-17.98,-6.79],P<0.00001);In diastolic blood pressure,the test group was better than the control group Group,the difference was statistically significant(OR=-7.42,95%CI[-8.53,-6.30],P<0.00001);In terms of adverse reactions,the difference was not statistically significant(OR=0.95,95%CI[0.29,3.16],P=0.94).Conclusions:In patients with acute myocardial infarction and heart failure,the timely application of neoactivin treatment can improve clinical efficacy,improve cardiac function,inhibit ventricular remodeling,improve blood pressure and heart rate,which has good clinical efficacy and safety.

Monte Carlo method for evaluation of surface emission rate measurement uncertainty

The aim of this study is to evaluate the uncertainty of 2πα and 2πβ surface emission rates using the windowless multiwire proportional counter method.This study used the Monte Carlo method (MCM) to validate the conventional Guide to the Expression of Uncertainty in Measurement (GUM) method.A dead time measurement model for the two-source method was established based on the characteristics of a single-channel measurement system,and the voltage threshold correction factor measurement function was indirectly obtained by fitting the threshold correction curve.The uncertainty in the surface emission rate was calculated using the GUM method and the law of propagation of uncertainty.The MCM provided clear definitions for each input quantity and its uncertainty distribution,and the simulation training was realized with a complete and complex mathematical model.The results of the surface emission rate uncertainty evaluation for four radioactive plane sources using both methods showed the uncertainty’s consistency E_(n)<0.070 for the comparison of each source,and the uncertainty results of the GUM were all lower than those of the MCM.However,the MCM has a more objective evaluation process and can serve as a validation tool for GUM results.

Analysis of Dimer Impurity in Polyamidoamine Dendrimer Solutions by Small-angle Neutron Scattering

Dimer impurity in the solution of a generation five(G5) polyamidoamine(PAMAM) dendrimer has been investigated by small-angle neutron scattering(SANS). The existence of dimer impurity in dendrimer solution was evidenced by indirect Fourier transform(IFT) analysis of the SANS data, in which the maximum dimension of particles in solution was found to be about twice the diameter of G5 dendrimer. We then developed an analytical model which accounts for the scattering contribution from both dendrimer monomer and dimer. The experimental data were well fitted by using the established model. The results showed that the amount of dimer impurities is significant for the measured three batches of G5 PAMAM dendrimers.

Research on protection system of resonant network in CSNS magnet power supplies

Purpose Chinese Spallation Neutron Source(CSNS)is one of the key projects of China,in which the main magnet power supplies adopt the structures of resonant networks(Wang et al.in Sci China Phys Mech Astron 54(Suppl 2):239-244,2011).Since each network contains a lot of components,and the working state of all the components will affect the whole accelerator,it is necessary to monitor the operation of each part in the resonant network.Methods In this protections system,a supervision to 314 switch signals and 118 analog signals is realized using a chip of field programmable gate array(FPGA).The details about the hardware and software designs are introduced in this paper.Results This protection system has been used in CSNS project,and the result proves that the RCS has been well monitored by this system.Conclusions This system is a self-developed protection system according to the engineering needs of CSNS.It can realize the real-time monitoring and protection of the working state of resonance network by processing a large number of data using FPGA.

The research of laser-based rapid measurement system for scintillator neutron detectors arrays

Purpose Scintillator Neutron Detectors Arrays(SNDA)were successfully installed at General Purpose Powder Diffractome-ter(GPPD)at the China Spallation Neutron Source(CSNS).The inhomogeneity of the detection efficiency in each detector module,which caused by the gain nonuniformity of the multi-anode photo-multiplier tubes(MA-PMTs)and the inconsistency of the wave-length shifting fibers in collecting scintillation photons,need to be mitigated before the installation.Methods An automated rapid measurement system based on the blue laser and the two-dimensional mobile platform was developed to calibrate the light response of each channel in detector modules.According to the test results of this system,the electronics threshold of each channel of the SNDA is adjusted.Before the installation of the all 40 SNDA modules in GPPD,the electronics thresholds of each channel are adjusted according to the measurement results of this rapid measurement system.Results and Conclusion Compared with the unadjusted detector module,the adjusted one obtained a better uniformity of the neutron detection efficiency.The inhomogeneity of the detection efficiency is improved from 27.4%to 10.9%.The test result of the diffraction peak of the standard sample Si showed that the adjusted SNDA works well in GPPD.