A depressant for marmatite flotation:Synthesis,characterisation and floatation performance

This study synthesised a zincic salt(ZS)as a depressant for marmatite-galena separation.The effect of ZS on the flotation of marmatite and galena was investigated through micro-flotation tests.88.89%of the galena was recovered and 83.39%of the marmatite was depressed with ZS dosage of 750 mg·L^(−1)at pH=4.The depression mechanism of ZS on marmatite was investigated by a variety of techniques,including adsorption measurements,Fourier transform infrared(FTIR),X-ray photoelectron spectroscopic(XPS)analysis,and time of flight secondary ion mass spectrometry(ToF-SIMS).Results of adsorption tests and FTIR reveal that ZS adsorbed on marmatite surface and impeded the subsequent adsorption of butyl xanthate(BX).The results of XPS and ToF-SIMS indicate that the ZnO_(2)^(3-)released by ZS could be chemisorbed on the marmatite surface and depress marmatite flotation.

Strain-hardening and warm deformation behaviors of extruded Mg-Sn-Yb alloy sheet

Strain-hardening and warm deformation behaviors of extruded Mg-2Sn-0.5Yb alloy(at.%)sheet were investigated in uniaxial tensile test at temperatures of 25-250 ℃ and strain rates of 1×10^(−3) s^(−1)-0.1 s^(−1).The data fit with the Kocks-Mecking type plots were used to show different stages of strain hardening.Besides III-stage and IV-stage,the absence of the II-stage strain hardening at room temperature should be related to the sufficient dynamic recrystallization during extrusion.The decrease of strain hardening ability of the alloy after yielding was attributed to the reduction of dislocation density with increasing testing temperature.Strain rate sensitivity(SRS)was significantly enhanced with increasing temperature,and the corresponding m-value was calculated as 0.07-0.12,which indicated that the deformation mechanism was dominated by the climb-controlled dislocation creep at 200 ℃.Furthermore,the grain boundary sliding(GBS)was activated at 250 ℃,which contributed to the higher SRS.The activation energy was calculated as 213.67 kJ mol^(−1),which was higher than that of lattice diffusion or grain boundary self-diffusion.In addition,the alloy exhibited a quasi superplasticity at 250 ℃ with a strain rate of 1×10^(−3) s^(−1),which was mainly related to the fine microstructure and the presence of the Mg2Sn and Mg2(Sn,Yb)particles.

Stabilization of Nanocrystalline Copper by Tantalum Grain Boundary Segregation

Nanocrystalline Cu-Ta alloy films were deposited on glass slides by magnetron sputtering. Microstructure characterization proved that most of the tantalum atoms are segregated in the grain boundaries. Nanoindentation creep measurements were performed on it to uncover the stability mechanism of grain boundary segregation on nanocrystalline materials. It is found that segregation can effectively slow down the creep strain rate and the grain boundary activities. The suppressed grain boundary activities endow the alloy with a stable microstructure during plastic deformation and annealing.

Preparation Technology and Property Research of Ultra-Concentrated Liquid Detergent

A series of ultra-concentrated liquid detergents （active matter content 〉 60%） was designed and formulated. The cold resisting, heat resisting and freeze-thaw stability of liquid detergent were tested, and their foaming power, detergency, pH value as well as water-saving property were evaluated by Ross-Miles foam meter, Terg-O-tometer, pH detector and surface tensionmeter, respectively. The results showed that the ultra-concentrated liquid detergents product displayed excellent stability. pH value of liquid detergents were less than 9 with less skin irritation. The foaming power of 0.05% （weight fraction） of liquid detergents was appreciably lower than 0.2% standard liquid detergent.The detergency of 0.05% （weight fraction） of liquid detergents was better than 0.2% standard liquid detergent, especially for artificial sebum stained clothes; the water-saving of liquid detergents was better than standard liquid detergent, the surfactant concentration of second rinse solution of standard liquid detergent was 5.3 times than that of concentrated liquid detergent.

Exploration for the Priority of HIV Intervention:Modelling Health Impact and Cost-Effectiveness—Six Cities,Eastern China,2019-2028

Introduction:In order to enhance the effectiveness of resource allocation,regions must tailor their responses to their specific epidemiological and economic situations.Methods:Utilizing Spectrum software,we projected the cost-effectiveness of 10 chosen HIV interventions in six cities in eastern China from 2019 to 2028.We assessed three scenarios—Base,Achievable,and Idealized—for each city.The analysis included the projected number of HIV infections and deaths averted,as well as the incremental costeffectiveness ratios for each intervention in the six cities.Results:In Shijiazhuang,Wuxi,Yantai,and Zhenjiang,cities with initially low antiretroviral therapy(ART)coverage,ART showed significant effectiveness,especially for males.Conversely,in Foshan and Ningbo,where ART coverage was notably high,oral pre-exposure prophylaxis(PrEP)for men who have sex with men(MSM)proved effective in the Idealized scenario.MSM outreach,ART for males,and ART for females demonstrated cost-effectiveness across all six cities in both Achievable and Idealized scenarios at the predefined thresholds for each city.Discussion:Maintaining an appropriate coverage rate for outreach to MSM can lead to costeffectiveness.In cities with low ART coverage,scaling up ART remains a crucial intervention.In regions with high ART coverage,consideration may be given to the utilization of oral PrEP for MSM individuals,requiring budget allocation.

Passive phase noise compensation for fiber-optic radio frequency transfer with a nonsynchronized source

We propose a passive compensation fiber-optic radio frequency（RF） transfer scheme with a nonsynchronized RF stable source during a round-trip time, which can avoid high-precision phase-locking and efficiently suppress the effect of backscattering only using two wavelengths at the same time. A stable frequency signal is directly reproduced by frequency mixing at the remote site. The proposed scheme is validated by the experiment over a 40 km single mode fiber spool using nonsynchronized common commercial RF sources. The influence of the stability of nonsynchronized RF sources on the frequency transfer is investigated over different length fiber links.

Estimating Costs of the HIV Comprehensive Intervention Using the Spectrum Model--China,2015-2019

Introduction:In order to facilitate human immunodeficiency virus(HIV)treatment and prevention,the resource needs for HIV national strategic planning in developing regions were estimated based on Spectrum,the universal HIV costeffectiveness analysis software.Methods:Based on the theoretical framework of Spectrum,the study developed a cost measurement tool for HIV,and calculated the cost of HIV prevention and control in 6 sampled cities in China during 2015–2019 using the Spectrum model.Results:From 2015 to 2019,the average annual costs for HIV prevention and control for Shijiazhuang,Yantai,Ningbo,Zhenjiang,Foshan,and Wuxi cities were 46.78,47.55,137.49,24.73,74.37,and 58.30 million Chinese yuan(CNY),respectively.The per capita costs were 4.37,6.73,17.33,7.77,17.56,and 8.91 CNY,respectively.In terms of the cost structure,the ratio of preventive intervention funds to therapeutic intervention funds(antiviral treatment)varied in sampled cities.Discussion:Developing comprehensive and systematic HIV fund calculation methods can provide a research basis for rational resource allocation in the field of HIV.