A short overview of the lead iodide residue impact and regulation strategies in perovskite solar cells

Lead iodide(PbI2) is a vital raw material for preparing perovskite solar cells(PSCs),and it not only takes part in forming the light absorption layer but also remains in the grain boundary as a passivator.In other words,the PbI2 content in the precursor and as formed film will affect the efficiency and stability of the PSCs.With moderate residual PbI2,it passivates the bulk/surface defects of perovskite,reduces the interfacial recombination,promotes the perovskite stability,minimizes the device hysteresis,and so on.Deficient PbI2 residue will reduce the interfacial passivation effect and device performance.In addition to facilitating the non-radiative recombination,over PbI2 residue can also lead to electronic insulation in the grain boundary and deteriorate the device performance.However,the impact and regulation of PbI2 residue on the device performance and stability is still not fully understood.Herein,a comprehensive and detailed review is presented by discussing the PbI2 residue impact and its regulation strategies(i.e., elimination,facilitation and conversion of the residue PbI2) to manipulate the PbI2 content,distribution and forms.Finally,we also show future outlooks in this field,with an aim to help further the progression of high-efficiency and stable PSCs.

Epicatechin attenuates lead(Pb)-induced cognitive impairment in mice:regulation on Nrf2 signaling pathway,and interference on the interaction between Pb with albumin

Epicatechin(EC)was used in this study to antagonize the cognitive dysfunction caused by lead(Pb)exposure in mice.Eight-week-old male Kunming mice were treated with PbCl_(2)(20 mg/kg)and/or EC(50 mg/kg)by gavage administration for 4 weeks.Morris water maze test showed that EC could improve memory dysfunction induced by Pb.EC antagonized Ca^(2+)overload,activated Nrf2 signaling pathway and reduced the accumulation of Pb in the brain and serum,which suggested that EC might alter Pb distribution in mice.In vitro,spectroscopic analysis,potentiometric titration and docking studies were applied to inquiry into the interaction between bovine serum albumin(BSA)and Pb^(2+)in presence or absence of EC.EC was proved to chelate Pb^(2+)and reduced the interaction between BSA and Pb^(2+).In summary,EC might protect Pb-induced cognitive impairment by activating Nrf2 signaling pathway,and suppressing Pb accumulation via interference on the binding of Pb to albumin.

Hot carrier cooling in lead halide perovskites probed by two-pulse photovoltage correlation spectroscopy

The next-generation hot-carrier solar cells,which can overcome the Shockley-Queisser limit by harvesting excessenergy from hot carriers,are receiving increasing attention.Lead halide perovskite(LHP)materials are considered aspromising candidates due to their exceptional photovoltaic properties,good stability and low cost.The cooling rate of hotcarriers is a key parameter influencing the performance of hot-carrier solar cells.In this work,we successfully detected hotcarrier dynamics in operando LHP devices using the two-pulse photovoltage correlation technique.To enhance the signalto-noise ratio,we applied the delay-time modulation method instead of the traditional power modulation.This advancementallowed us to detect the intraband hot carrier cooling time for the organic LHP CH_(3)NH_(3)PbBr_(3),which is as short as 0.21 ps.In comparison,the inorganic Cs-based LHP CsPbBr_(3)exhibited a longer cooling time of around 0.59 ps due to differentphonon contributions.These results provide us new insights into the optimal design of hot-carrier solar cells and highlightthe potential of LHP materials in advancing solar cell technology.

Seasonal Characteristics of Forecasting Uncertainties in Surface PM_(2.5)Concentration Associated with Forecast Lead Time over the Beijing-Tianjin-Hebei Region

Forecasting uncertainties among meteorological fields have long been recognized as the main limitation on the accuracy and predictability of air quality forecasts.However,the particular impact of meteorological forecasting uncertainties on air quality forecasts specific to different seasons is still not well known.In this study,a series of forecasts with different forecast lead times for January,April,July,and October of 2018 are conducted over the Beijing-Tianjin-Hebei(BTH)region and the impacts of meteorological forecasting uncertainties on surface PM_(2.5)concentration forecasts with each lead time are investigated.With increased lead time,the forecasted PM_(2.5)concentrations significantly change and demonstrate obvious seasonal variations.In general,the forecasting uncertainties in monthly mean surface PM_(2.5)concentrations in the BTH region due to lead time are the largest(80%)in spring,followed by autumn(~50%),summer(~40%),and winter(20%).In winter,the forecasting uncertainties in total surface PM_(2.5)mass due to lead time are mainly due to the uncertainties in PBL heights and hence the PBL mixing of anthropogenic primary particles.In spring,the forecasting uncertainties are mainly from the impacts of lead time on lower-tropospheric northwesterly winds,thereby further enhancing the condensation production of anthropogenic secondary particles by the long-range transport of natural dust.In summer,the forecasting uncertainties result mainly from the decrease in dry and wet deposition rates,which are associated with the reduction of near-surface wind speed and precipitation rate.In autumn,the forecasting uncertainties arise mainly from the change in the transport of remote natural dust and anthropogenic particles,which is associated with changes in the large-scale circulation.

Revisiting the theoretical prediction of the explosive performance found by the Trauzl test

The Trauzl lead block test allows the determination of the approximate performance of explosives in blasting applications by measuring the volume increase(expansion)that is produced by the detonation of an explosive charge in the cavity of a lead block.In this paper,we reconsider the possibility of interpreting the Trauzl test results in terms of detonation parameters or quantities.The detonation parameters used in the analysis are calculated using the thermochemical code EXPLO5,while the hydrocode AUTODYN is used to simulate the effect of explosive charge density and reaction rate on the results of the Trauzl test.The increase in the volume of the lead block cavity was found to correlate best with the product of the detonation heat and the root of the volume of detonation products.Hydrocode simulation showed that the density of explosive charge and the rate of explosive decomposition affect the dynamics of the interaction of the detonation product and the lead block,and consequently the lead block cavity volume increase.

Arrhythmia Detection by Using Chaos Theory with Machine Learning Algorithms

Heart monitoring improves life quality.Electrocardiograms(ECGs or EKGs)detect heart irregularities.Machine learning algorithms can create a few ECG diagnosis processing methods.The first method uses raw ECG and time-series data.The second method classifies the ECG by patient experience.The third technique translates ECG impulses into Q waves,R waves and S waves(QRS)features using richer information.Because ECG signals vary naturally between humans and activities,we will combine the three feature selection methods to improve classification accuracy and diagnosis.Classifications using all three approaches have not been examined till now.Several researchers found that Machine Learning(ML)techniques can improve ECG classification.This study will compare popular machine learning techniques to evaluate ECG features.Four algorithms—Support Vector Machine(SVM),Decision Tree,Naive Bayes,and Neural Network—compare categorization results.SVM plus prior knowledge has the highest accuracy(99%)of the four ML methods.QRS characteristics failed to identify signals without chaos theory.With 99.8%classification accuracy,the Decision Tree technique outperformed all previous experiments.

Moving Firmly Forward New CPC Central Committee session charts course for further opening up

Nearly five decades after the third plenary session of the 11th Central Committee of the Communist Party of China(CPC)in 1978,which launched the historic reform and opening up policy that transformed China,the CPC held another third plenary session that promises to be potentially as consequential.The resolution passed on 18 July during the third plenary session of the 20th Central Committee of the CPC calls for comprehensively deepening reforms,thus paving the way for the country to march towards the final goal of a developed and prosperous country.

Exploring the Path of Party Building Leading League Construction in Colleges and Universities under the Pattern of Great Ideological and Political Education

In accordance with the pattern of"great ideology and politics",the Party and youth League organizations assume the role of vanguard in the organization of colleges and universities.Simultaneously,they serve as a pivotal force in ideological and political education.In order to construct a comprehensive ideological and political framework encompassing the entire educational process,it is of paramount importance to identify an efficacious methodology for Party building leading League construction.This paper employs a comprehensive analysis to elucidate the pivotal role of Party building leading League construction in facilitating ideological and political education.It also illuminates the practical challenges encountered in the implementation of Party building leading League construction initiatives within colleges and universities.The article proposes a specific path for Party building leading League construction in colleges and universities based on three key aspects:cohesion of the consensus of Party building leading League building,establishment of the institutional system of Party building leading League construction,and creation of the model brand of Party building leading League construction.The aim is to promote in-depth development of Party building in colleges and universities and enhance the quality and effect of ideological and political education.

Exogenous addition of nitrate nitrogen regulates the uptake and translocation of lead (Pb) by Iris lacteal Pall. var. chinensis (Fisch.) Koidz.

Since Pb is a non-biodegradable inorganic pollutant and a non-essential metal,its long-term presence in soil poses a great threat to the environment.Iris lactea Pall.var.chinensis(Fisch.)Koidz.,a perennial dense bush herb with high resistance of Pb and wide adaptability,was used in pot experiments to study the effects of exogenous nitrate N(NO_(3)^(–)-N)on the absorption and transportation of Pb and plant growth under different Pb concentrations.Then,the mechanism of NO_(3)^(-)-N affecting Pb and nutrient uptake and transport was explored.The concentration of Pb in the experiment ranged from 0 to 1600 mg/kg,and the added concentration of NO_(3)^(-)-N was 0.0–0.3 g/kg.The results showed that I.lactea was highly tolerant to Pb,and the shoot fraction was more sensitive to varied Pb concentrations in the soil than the root fraction.This protective function became more pronounced under the condition of raised Pb concentration in the soil.When the concentration of Pb in the soil reached 800 mg/kg,the highest Pb content of I.lactea was found under the condition of 0.1 g/kg of NO–3-N addition.When Pb concentration in the soil increased to 1600 mg/kg,the increase in NO_(3)^(-)-N addition promoted Pb uptake by the root.To ensure the well growth of I.lactea and the effect of remediation of Pb-contaminated soil,the recommended concentration of NO–3-N in the soil is 0.1 g/kg.This result provides a theoretical basis for exogenous N regulation of phytoremediation of Pb-contaminated soil.

The Centenary of the CPC: Leading the Times by Grasping the Laws and Trends of Historical Development

Discussions on grasping the laws and trends of historical development take a fundamental theoretical position in the scientific system of Xi Jinping Thought on Socialism with Chinese Characteristics for a New Era.Xi Jinping’s important statements have systematically answered such questions as what type of laws and trends of historical development should be followed,how did the Party follow the laws and trends of historical development in its centennial history,and how should the laws and trends of historical development be followed in a new era.The birth of the Communist Party of China(CPC),the victory of China’s War of Resistance against Japanese Aggression,the founding of the People’s Republic of China,and the unveiling of a new era for reform and opening up and socialism with Chinese characteristics are all the results of grasping the laws and trends of historical development.Over the past century,the Party has followed the laws and trends of historical development and continuously advanced the sinicization of Marxism on the basis of adhering to the unification between truth and values.In pursuit of“putting people first,”the Party has courageously been reforming itself and made relentless progress in the great endeavor of Party building.History shows that a keen appreciation of the laws and trends of historical development is an important sign of political maturity for a proletarian party.Only by applying Marxism according to current times and conditions will we keep abreast with the laws and trends of historical development.We should establish a broader concept of history and identify the laws and trends of historical development from the interactions and linkages between China and the rest of the world.We must recognize and promote the outstanding role of great leaders in steering the country in line with the laws and trends of historical development.

Thermodynamics of removing impurities from crude lead by vacuum distillation refining

A novel technique was developed to remove impurities from crude lead by vacuum distillation.The thermodynamics on vacuum distillation refining process of crude lead was studied by means of saturated vapor pressure of main components of crude lead,separation coefficients and vapor-liquid equilibrium composition of Pb-i（i stands for an impurity） system at different temperatures.The behaviors of impurities in the vacuum distillation refining process were investigated.The results show that the vacuum distillation should be taken to obtain lead from crude lead,in which Zn,As and partial Sb are volatilized at lower temperature of 923-1023 K.Lead is distilled from the residue containing Cu,Sn,Ag and Bi at higher temperature of 1323-1423 K,but the impurity Bi is also volatilized along with lead and cannot be separated from lead.

CPC/PMMA复合骨水泥联合明胶海绵预防伴椎体前壁破裂骨质疏松性椎体骨折术中骨水泥渗漏的疗效观察

随着老龄化社会的到来,骨质疏松性椎体压缩性骨折发病率呈现不断上升趋势[1],临床上常采用经皮椎体后凸成形术治疗老年骨质疏松性椎体压缩性骨折并取得了良好效果[2]。随着该技术的普及,相关手术并发症也日益凸显,尤其是骨水泥渗漏问题[3]。目前骨水泥以聚甲基丙烯酸甲酯(PMMA)的应用最为广泛,但其缺乏生物活性且弹性模量高;而磷酸钙骨水泥(CPC)虽具有一定的强度,后期降解后存在支撑力不够的问题。在单独使用时两者均非理想的骨水泥,有研究表明CPC/PMMA两种材料按一定比例调配可兼顾两者的优点,是临床上具有应用潜力的骨水泥[4]。在临床中老年骨质疏松性椎体骨折常伴随着椎体前壁的破裂,骨水泥易从破裂的骨皮质处渗漏,为减少骨水泥的渗漏、提高手术的安全性,笔者采用明胶海绵封堵裂口、CPC/PMMA复合骨水泥注射治疗,取得了满意的效果,现报道如下。

Effects of field application of phosphate fertilizers on the availability and uptake of lead, zinc and cadmium by cabbage (Brassica chinensis L.) in a mining tailing contaminated soil

A field trial was conducted to evaluate the reduction of bioavailability of heavy metals including lead (Pb), zinc (Zn) and cadmium (Cd) in a soil contaminated by mining tailings in Shaoxing, Zhejiang, China. Three commercial phosphate (P) fertilizers including phosphate rock (PR), calcium magnesium phosphate (CMP), and single superphosphate (SSP) were applied to the plot at three P application rates, 50, 300, and 500 g/m2 with 9 treatments and control (CK). Plants, water soluble and exchangeable (WE) extra...

Multi-biological defects caused by lead exposure exhibit transferable properties from exposed parents to their progeny in Caenorhabditis elegans

Whether the multi-biological toxicity from lead exposure could be transferred to progeny has not been clarified. In the present study, we explored the Caenorhabditis elegans to analyze the multiple toxicities from lead exposure and their possibly transferable properties. The lead exposure could cause series of severe multi-biological defects with a concentration-dependent manner by affecting the endpoints of life span, development, reproduction and locomotion behaviors in nematodes. Moreover, most of these toxicities could be transferred to progeny from lead exposed animals and some of the defects in progeny appeared even more severe than in their parents, such as the body sizes and mean life spans. We summarized the defects caused by lead exposure into three groups according to their transferable properties or rescue patterns. That is, the defects caused by lead exposure could be largely, or partially, or became even more severe in progeny animals. Therefore, our results suggest that lead exposure can cause severely multi-biological defects, and most of these multiple toxicities can be considered as transferable for exposed animals in C. elegans.

Numerical Study on the Duct Noise Control of Single-Stage Axial Flow Fan with Wave Leading Edge Stator Blade Configurations

This study focuses on a single-stage axial flow fan, investigating the effect of three kinds of wave leading edge stator blades on its noise reduction. The DDES method and the duct acoustic analogy theory based on the penetrable data surface were used for noise prediction. The results showed that the three kinds of wave leading edge blades were effective in reducing the rotor-stator interaction tonal noise and also have a certain inhibitory effect on broadband noise. The A10W15 stator blade can effectively reduce broadband noise in the frequency range of 2200 - 4200 Hz. When the amplitude is increased to 20, the noise reduction effect is further enhanced. However, when the amplitude is increased to 30, the broadband noise reduction effect is no longer significant. Further research shows that the wave leading edge stator blades can significantly change the pressure fluctuation distribution on the leading edge and suction surface, which control the modal energy distribution. Finally, this paper analyzed multiple factors affecting the broadband noise reduction, such as the noise source cut-off and cut-on effect and correlation. The purpose of this paper is to explore the laws of the influence of wave leading edge blades on the duct noise of real fan, and to reveal its noise control mechanism. .

The Protective Effect of Ascorbic Acid and Thiamine Supplementation against Damage Caused by Lead in the Testes of Mice

Lead is a ubiquitous environmental and industrial pollutant that may have toxic effects on the male. Vitamins may protect against toxic effects of lead in the liver and reproductive system, which is confirmed by our initial research. The aim of this study was to further investigate the protective effects of vitamins （ascorbic acid combined with thiamine） on lead acetate （Pb）-induced reproductive toxicities in mice and study the possible mechanisms underlying these effects. Forty-five male mice were randomly divided into 3 groups, 15 mice in each and received daily intragastric administration with control, Pb （20 mg/kg）, and Pb＋vitamins （ascorbic acid of 420 mg/kg＋thiamine of 30 mg/kg） for 6 weeks, respectively. The Pb-treated animals showed significant decreases in the epididymal sperm count and motility compared to the control group, while the Pb＋vitamins group had significant increases for these variables. Moreover, an increasing apoptosis of germinal cells induced by Pb was reduced by vitamin treatment. Pb induced the activation of Caspase-3, Fas/Fas-L and Bcl-2 with elevated levels, and the adaptor protein primarily regulated signaling through Fas and required for Fas-induced apoptosis. In conclusion, ascorbic acid combined with thiamine exhibited protective effect on reproductive system by inhibiting Pb-induced excessive cell apoptosis.

Dynamical Predictability of Leading Interannual Variability Modes of the Asian-Australian Monsoon in Climate Models

The dynamical prediction of the Asian-Australian monsoon(AAM)has been an important and long-standing issue in climate science.In this study,the predictability of the first two leading modes of the AAM is studied using retrospective prediction datasets from the seasonal forecasting models in four operational centers worldwide.Results show that the model predictability of the leading AAM modes is sensitive to how they are defined in different seasonal sequences,especially for the second mode.The first AAM mode,from various seasonal sequences,coincides with the El Niño phase transition in the eastern-central Pacific.The second mode,initialized from boreal summer and autumn,leads El Niño by about one year but can exist during the decay phase of El Niño when initialized from boreal winter and spring.Our findings hint that ENSO,as an early signal,is conducive to better performance of model predictions in capturing the spatiotemporal variations of the leading AAM modes.Still,the persistence barrier of ENSO in spring leads to poor forecasting skills of spatial features.The multimodel ensemble(MME)mean shows some advantage in capturing the spatiotemporal variations of the AAM modes but does not provide a significant improvement in predicting its temporal features compared to the best individual models in predicting its temporal features.The BCC_CSM1.1M shows promising skill in predicting the two AAM indices associated with two leading AAM modes.The predictability demonstrated in this study is potentially useful for AAM prediction in operational and climate services.

EBM联合CPC在《中医全科医学概论》教学中的应用

目的探讨在《中医全科医学概论》教学中融入EBM和CPC中的应用效果。方法选取本校2019级中医学(全科方向)65名学生作为研究对象,课程中融入EBM和CPC,课程结束后发放调查问卷。结果回收有效问卷50份。通过描述统计对“融入循证医学的必要性”“增加课程趣味性和实用性”“提高解决临床问题的能力”等问卷条目进行分析,结果显示平均值均接近4,说明50位同学对《中医全科医学概论》课程融入循证医学内容比较认可。在课程融入社区卫生实践必要性层面,72%学生认为有必要融入社区卫生实践。他们认为增加实践,首先可以了解社区卫生服务情况(88%),其次也可以增加感官认知(74%)。结论《中医全科医学概论》融入EBM和CPC值得进一步研究应用。

Investigation on the deactivation cause of lead-zinc double oxide for the synthesis of diphenyl carbonate by transesterification

The deactivation cause of lead-zinc double oxide for synthesis of diphenyl carbonate （DPC） by transesterification of dimethyl carbonate （DMC） with phenol has been investigated. X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS）, infrared spectroscopy （IR）, thermogravimetry analysis （TG）, atomic absorption spectroscopy and elementary analysis are employed for the catalyst characterization. The results show that, the formation of Pb4O（OC6H5）6 through the reaction of phenol and lead species in the catalyst leads to the crystal phase change of active component and serious leaching of lead, which is the cause of the catalyst deactivation. In addition, the composition of the leached lead is ascertained to be a mixture of Pb4O（OC6H5）6 and PbO with the weight percentage of 62.7% and 37.3%, respectively.

Studies on the Behaviors of PbSO_4/Pb and PbO_2/PbSO_4 Electrodes Prepared from Lead Carbonate by Powder Microelectrode Technique

The behaviors ot PbSO4/Pb and PbO4/PbSO4 electrode prepared from PbCO3 have been examined using powder microelectrode(PME) technique and cyclic voltammetry(CV). Firstly, PMEs parked with Pb- CO3 transformed into PtSO4 PME in 1. 0 mol/L H2SO4 solution at 30 C, and then the PbSO4 in the PMEs were formed to Pb or PbO2 using an unsymmetrical signal(Qa/Qe for PbSO4/Pb electrode and Qe/Qa for PsO2/ PbSO4 electrode being 0. 1-0. 3) in 2. S mol/L H2SO4 solution. The results show that the CV characteristic of either PbSO4/Pb or PsO2/PbSO4 PME prepared from PhCO3 are as good as that of both electrodes made from lead oxide powder produced by ball mill.