Geological characteristics,metallogenic regularity,and research progress of lithium deposits in China

China is rich in abundant lithium resources characterized by considerable reserves and a concentrated distribution of metallogenic zones or belts,with proven reserves of 4046.8×10^(3) t(calculated based on Li_(2)O)by 2021.China is also a big consumer of lithium.By 2019,China’s lithium consumption in the battery sector alone had reached 99×10^(3) t,with an average annual growth rate of nearly 26%.China has become the world’s largest importer of lithium resources,showing a severely unbalanced relationship between supply and demand for lithium resources.Therefore,there is an urgent need for the prospecting,exploitation,and study of lithium resources in China.This study collected,organized,and summarized the data on the major lithium deposits in China,analyzed and compared the spatial-temporal distribution patterns,geological characteristics,and metallogenic regularity of these lithium deposits,and summarized the prospecting and research achievements over the last decade.The major lithium deposits in China are distributed in provinces and regions such as Qinghai,Jiangxi,Sichuan,Tibet,and Xinjiang.These deposits are mostly small in scale.According to different genetic types,this study divided lithium deposits into granitic pegmatite type,granite type,saline lake brine type,underground brine type,and sedimentary type,as well as new types including hot spring type and magmatic-hydrothermal type,and summarized the characteristics and key metallogenic factors of these different types of deposits.Sixteen metallogenic prospect areas of lithium deposits were delineated according to the deposit types and the distribution patterns of metallogenic belts.The paper introduced the research progress in major metallogenic models and lithium extraction techniques made over the past decade.Based on the comprehensive analysis of the prospecting potential of lithium deposits,the authors concluded that the future prospecting of lithium resources in China should focus on lithium metallogenic belts,the deep and peripheral areas of currently determined large-scale pegmatite-type lithium deposits,geophysical-geochemical anomalous areas with mineralization clues,and areas with developed large-scale low-grade associated granite-type and sedimentary lithium resources.The study aims to serve as a guide for the future prospecting of lithium deposits in China.

Transient analysis and optimization of passive residual heat removal heat exchanger in advanced nuclear power plant

The transient performance and optimization of a passive residual heat removal heat exchanger(PRHR HX)were investigated.First,a calculation method was developed for predicting the heat transfer of the PRHR HX.The calculation results were validated through comparisons with ROSA experimental data.The heat-transfer performance of the AP1000 PRHR HX in the initial period was predicted,and it satisfied the design requirements.Second,the distributions of the heat flux,tube-inside/outside heattransfer coefficients,and heat load for the AP1000 PRHR HX over 2000 s were examined.Third,an optimization study was conducted by adjusting the horizontal length and tube diameter.Their effects on the four main heat-transfer parameters and the heat-transfer area were analyzed.Furthermore,the influence of the initial in-containment refueling water storage tank(IRWST)temperature was investigated using an established simulation procedure.The results indicated that it significantly affected the trends of the IRWST temperature and reactor outlet temperature.Finally,the minimum required flow rates over time to maintain the reactor outlet temperature at the safety line were determined for different start-up times.The trends of the minimum required flow rate and the peak flow rate were analyzed.

Renal and perinephric abscesses in West China Hospital:10-year retrospective-descriptive study

AIM： To elucidate the clinical, radiological and laboratory pro？les of renal abscess （RA） and perinephric abscess （PNA）, along with related treatment and outcome.METHODS： Ninety-eight patients diagnosed with RA or PNA using the primary discharge diagnoses identi？ed from the International Statistical Classification of Diseases and Related Health Problems Tenth Edition （ICD-10） codes （RA： N15.101, PNA： N15.102） between September 2004 and December 2014 in West China Hospital were selected. Medical records including patients’ characteristics, symptoms and signs, high-risk factors, radiological features, causative microorganisms and antibiotic-resistance pro？les, treatment approaches, and clinical outcomes were collected and analyzed.RESULTS： The mean age of the patients was 46.49 years with a male to female ratio of 41：57. Lumbar pain （76.5%） and fever （53.1%） were the most common symptoms. Other symptoms and signs included chills （28.6%）, anorexia and vomiting （25.5%）, lethargy （10.2%）, abdominal pain （11.2%）, fank mass （12.2%）, fank ？stula （2.0%）, gross hematuria （7.1%）, frequency （14.3%）, dysuria （9.2%）, pyuria （5.1%） and weight loss （1.0%）. Painful percussion of the costovertebral angle （87.8%） was the most common physical ？nding. The main predisposing factors were lithiasis （48.0%）, diabetes mellitus （33.7%） followed by history of urological surgery （16.3%）, urinary tract infections （14.3%）, renal function impairment （13.3%）, liver cirrhosis （2.0%）, neurogenic bladder （1.0%）, renal cyst （1.0%）, hydronephrosis （1.0%）, chronic hepatitis B （1.0%）, post-discectomy （1.0%） and post-colectomy （1.0%）. Ultrasound （US） and computed tomography were the most valuable diagnostic tools and US was recommended as the initial diagnostic imaging choice.Escherichia coli （51.4%）, Staphylococcus aureus （10.0%） and Klebsiella pneumoniae （8.6%） were the main causative microorganisms. Intravenous antibiotic therapy was necessary while intervention including surgical and nonsurgical approaches were reserved for larger abscesses, multiple abscesses, PNAs and non-responders. CONCLUSION： Heightened alertness, prompt diagnosis, and especially proper antibiotics in conjunction with interventional approaches allow a promising clinical outcome of renal and perinephric abscesses.

面向控制的空天飞行器低速段动力学建模及性能折衷分析（英文）

目的:水平起降空天飞行器需兼顾高速巡航和低速起降性能。本文旨在构建一种面向控制的空天飞行器低速段动力学建模与迭代分析流程,探究质心位置对空天飞行器稳定性及控制性能的影响,并在保证空天飞行器水平起降能力的约束下,迭代获得合理的飞行器质心位置。创新点:1.结合几何外形参数化方法、势流理论和0维混合排气涡扇发动机建模方法实现空天飞行器低速段气动/推进性能数据的快速获取;2.基于所获得的气动/推进性能数据,开展代理建模研究,获得适用于性能分析及控制器设计需要的气动力/力矩系数代理模型;3.基于可变质心的气动力/力矩系数代理模型进行空天飞行器水平起降性能分析及质心位置迭代设计。方法:1.通过形状/类型函数法建立空天飞行器几何参数化模型;2.基于势流理论和0维涡扇发动机理论快速获取空天飞行器低速段气动/推进性能数据;3.通过代理模型技术,获得不同质心位置下的飞行器气动力/力矩系数拟合表达式,并基于该表达式确定符合水平起降约束的质心位置。结论:1.空天飞行器研究中,需综合考虑高低速性能,并协调水平起降、稳定性和控制性能等多方面指标;2.本文所提出的空天飞行器概念方案,满足抬头、触地约束的质心范围在距机头65%机身长度处;3.本文所提出的面向控制建模与性能分析流程可以满足空天飞行器概念方案阶段数据快速获取、方案快速迭代优化的要求。