Manipulating unintentional doping in graphene layers, which is influenced by environmental factors and supporting substrates, is of significant concern for the performance and advancement of graphene-based devices. In...Manipulating unintentional doping in graphene layers, which is influenced by environmental factors and supporting substrates, is of significant concern for the performance and advancement of graphene-based devices. In this context,laser-induced tuning of charge carriers in graphene facilitates the exploration of graphene's properties in relation to its surroundings and enables laser-assisted functionalization. This has the potential to advance optoelectronic devices that utilize graphene on transparent dielectric substrates, such as Al_(2)O_(3). In this work, laser power(PL) in Raman spectroscopy is used as a convenient contactless tool to manipulate and control unintentional carrier concentration and Fermi level position(EF) in graphene/α-Al_(2)O_(3)(G/Al_(2)O_(3)) under ambient conditions. Samples are annealed at 400℃ for two hours in an(Ar + H_(2)) atmosphere to remove any chemical residues. Analysis of the peak frequency(ω) and full width at half maximum(Γ) of the G and 2D bands show that G/Al_(2)O_(3) layers initially exhibit p-type doping, with EF located at ~100 me V below its Dirac charge-neutral point(DCNP). Increasing P_(L) results in effective carrier manipulation and raises E_F above DCNP. No significant internal stress is produced due to P_(L), as inferred from the strain-sensitive G^(*) band of graphene. Raman analysis of three successive cycles reveals hysteretic behavior from cycle to cycle, which is commonly reported to be limited by the type and density of the existing unintentional doping. Because of the ubiquitous nature of unintentional doping in graphene,manipulating it using contactless laser power to realize the desired graphene properties would be one of the best available practical approaches.展开更多
Diamond with silicon vacancies has an important role as a promising single-photon source applicable in the quantum information field.However,in a microwave plasma chemical vapor deposition(MPCVD)system,due to the pres...Diamond with silicon vacancies has an important role as a promising single-photon source applicable in the quantum information field.However,in a microwave plasma chemical vapor deposition(MPCVD)system,due to the presence of unintentional silicon doping sources such as quartz windows,the behavior of silicon vacancy formation in silicon-doped diamond is complex.In this work,the underlying mechanism of formation of silicon vacancies by unintentional silicon doping in diamond is investigated from the perspective of growing surface kinetics in a two-gas-flow MPCVD system.This system is equipped with a novel susceptor geometry designed to deliver an additional gas flow directly onto the substrate surface.Increasing the concentration of growth doping substances on the substrate surface thereby enhances the efficiency of silicon vacancy formation in diamond.At the same time,by changing the substrate deposition angle the distribution of gas and plasma on the substrate surface is changed,thereby regulating the concentration and distribution of silicon vacancies formed by unintentional silicon doping.Experimental and computational results demonstrate that the difference in silicon vacancies formed by unintentional silicon doping in diamond depends on the substances present on the substrate surface and the distribution of plasma.展开更多
The forking problem plays a key role in the security issue,which is a major concern in the blockchain system.Although many works studied the attack strategy,consensus mechanism,privacy-protecting and security performa...The forking problem plays a key role in the security issue,which is a major concern in the blockchain system.Although many works studied the attack strategy,consensus mechanism,privacy-protecting and security performance analysis,most of them only address the intentional forking caused by a malicious attacker.In fact,without any attacker,unintentional forking still remains due to transmission delay and failure,especially in wireless network scenarios.To this end,this paper investigates the reason for generating unintentional forking and derives the forking probability expression in Wireless Blockchain Networks(WBN).Furthermore,in order to illustrate the unintentional forking on the blockchain system,the performances in terms of resource utilization rate,block generation time,and Transaction Per Second(TPS)are investigated.The numerical results show that the target difficulty of hash algorithm in generating a new block,the delay time of broadcasting,the network scale,and the transmission failure probability would affect the unintentional forking probability significantly,which can provide a reliable basis for avoiding forking to save resource consumption and improving system performance.展开更多
Radio frequency fingerprinting(RFF)is a technology that identifies the specific emitter of a received electromagnetic signal by external measurement of the minuscule hardware-level,device-specific imperfections.The RF...Radio frequency fingerprinting(RFF)is a technology that identifies the specific emitter of a received electromagnetic signal by external measurement of the minuscule hardware-level,device-specific imperfections.The RFF-related information is mainly in the form of unintentional modulation(UIM),which is subtle enough to be effectively imperceptible and is submerged in the intentional modulation(IM).It is necessary to minimize the influence of the IM and expand the slight differences between emitters for successful RFF.This paper proposes a UIM microstructure enlargement(UMME)method based on feature-level adaptive signal decomposition(ASD),accompanied by autocorrelation and cross-correlation analysis.The common IM part is evaluated by analyzing a newly-defined benchmark feature.Three different indexes are used to quantify the similarity,distance,and dependency of the RFF features from different devices.Experiments are conducted based on the real-world signals transmitted from 20 of the same type of radar in the same working mode.The visual image qualitatively shows the magnification of feature differences;different indicators quantitatively describe the changes in features.Compared with the original RFF feature,recognition results based on the Gaussian mixture model(GMM)classifier further validate the effectiveness of the proposed algorithm.展开更多
AlGaN/GaN high electron mobility transistors （HEMTs） grown on Fe-modulation-doped （MD） and unintentionally doped （UID） GaN buffer layers are investigated and compared. Highly resistive GaN buffers （10^9Ω·...AlGaN/GaN high electron mobility transistors （HEMTs） grown on Fe-modulation-doped （MD） and unintentionally doped （UID） GaN buffer layers are investigated and compared. Highly resistive GaN buffers （10^9Ω·cm） are induced by individual mechanisms for the electron traps＇ formation： the Fe MD buffer （sample A） and the UID buffer with high density of edge-type dislocations （7.24×10^9cm^-2, sample B）. The 300K Hall test indicates that the mobility of sample A with Fe doping （2503cm^2V^-1s^-1） is much higher than sample B （1926cm^2V^-1s^-1） due to the decreased scattering effect on the two-dimensional electron gas. HEMT devices are fabricated on the two samples and pulsed I–V measurements are conducted. Device A shows better gate pinch-off characteristics and a higher threshold voltage （-2.63V） compared with device B （-3.71V）. Lower gate leakage current ｜IGS｜ of device A （3.32×10^-7A） is present compared with that of device B （8.29×10^-7A）. When the off-state quiescent points Q_2 （V GQ2=-8V, V DQ2=0V） are on, V th hardly shifts for device A while device B shows ＋0.21V positive threshold voltage shift, resulting from the existence of electron traps associated with the dislocations in the UID-GaN buffer layer under the gate. Under pulsed I–V and transconductance G m–V GS measurement, the device with the Fe MD-doped buffer shows more potential in improving reliability upon off-state stress.展开更多
The study of brain function in the presence of pain and injury is a rapidly expanding field of experimental research.Clinically,the presence of pain and injury is often accompanied by reports of behavioural change and...The study of brain function in the presence of pain and injury is a rapidly expanding field of experimental research.Clinically,the presence of pain and injury is often accompanied by reports of behavioural change and altered cognition.Even in a highly controlled environment such as the surgical operating theatre postoperative behavioural changes including posttraumatic stress disorder,depression,chronic fatigue,展开更多
Extensive experiments suggest that kurtosis-based fingerprint features are effective for specific emitter identification (SEI). Nevertheless, the lack of mechanistic explanation restricts the use of fingerprint featur...Extensive experiments suggest that kurtosis-based fingerprint features are effective for specific emitter identification (SEI). Nevertheless, the lack of mechanistic explanation restricts the use of fingerprint features to a data-driven technique and fur-ther reduces the adaptability of the technique to other datasets. To address this issue, the mechanism how the phase noise of high-frequency oscillators and the nonlinearity of power ampli-fiers affect the kurtosis of communication signals is investigated. Mathematical models are derived for intentional modulation (IM) and unintentional modulation (UIM). Analysis indicates that the phase noise of high-frequency oscillators and the nonlinearity of power amplifiers affect the kurtosis frequency and amplitude, respectively. A novel SEI method based on frequency and ampli-tude of the signal kurtosis (FA-SK) is further proposed. Simula-tion and real-world experiments validate theoretical analysis and also confirm the efficiency and effectiveness of the proposed method.展开更多
During the start-up and unstable combustion periods,even the state-of-the-art incinerators emit polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/PCDF) in stack gases at concentrations that are up to 1000 times...During the start-up and unstable combustion periods,even the state-of-the-art incinerators emit polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/PCDF) in stack gases at concentrations that are up to 1000 times higher than normal operation. Therefore,incinerators and other sources with variation of PCDD/PCDF release into air cannot be reliably monitored by the conventional short-term sampling that covers only 0.1%to 0.2%of the yearly operating time.A more comprehensive monitoring regime is required.This paper describes different applications of continuous PCDD/PCDF sampling in some European countries.The cases demonstrate that flexible regimes for continuous sampling can be crafted and applied by governments or regional/local authorities.Such regimes range from a countrywide,continuous requirement for selected facility types(e.g.,waste incinerators) to a facility-specific regime that applies,for example,to new facilities for a defined time period until the facility has demonstrated continuous compliance with regulatory limits. Countries implementing the Stockholm Convention are suggested to evaluate in their Best available technology/Best environmental practice(BAT/BEP) activities the usefulness of long-term sampling by,for example,designating institutes related to the environmental ministry or regional authorities to supervise long-term sampling regimes at relevant facilities in their country/areas,beginning with priority sources(e.g.,facilities used for destruction of persistent organic pollutants(POPs) or hazardous waste processing) . This paper presents and discusses the results of the AMESA long-term monitoring system having demonstrated that in addition to PCDD/PCDF all other unintentionally produced POPs listed in the Stockholm Convention could be supervised.展开更多
Background::Non-transport unintentional injuries(NTUIs)are major public concerns,especially among children and adolescents in low-and middle-income countries.With environmental and cognitive changes,a recent systemati...Background::Non-transport unintentional injuries(NTUIs)are major public concerns,especially among children and adolescents in low-and middle-income countries.With environmental and cognitive changes,a recent systematic description of global trends and regional differences concerning NTUIs is urgently needed for the global agenda of relevant policy-making and intervention target findings.Methods::We used mortality,population,and socio-demographic-index(SDI)data from Global Burden of Disease 2019 to analyze the trends of NTUIs mortality.We applied the slope index of inequality(SII)and relative index of inequality(RII)to measure the absolute and relative inequality between countries and territories.The concentration curve and concentration index(CI)were also used to measure the inequality.We conducted a sensitivity analysis to make our findings credible.Results::In 2019,there were 205,000 deaths due to NTUIs among children and adolescents aged 5 to 24 years,which decreased from 375,000 in 1990.In 2019,the age-standardized mortality rate(ASMR)was 8.13 per 100,000,ranging from the lowest in the Netherlands(0.90 per 100,000)to the highest in the Solomon Islands(29.34 per 100,000).The low-middle SDI group had the highest ASMR of NTUIs,while the low SDI group had the slowest decrease.After excluding the death caused by"exposure to forces of nature"and"other unintentional injuries",drowning accounted for the most deaths in almost every SDI group,gender,and age group,but the major causes of death varied in different subgroups.For example,animal contact was a major cause in low and low-middle SDI groups but less in high SDI groups,while high and high-middle SDI groups had a higher proportion of deaths for foreign body and poisonings.The SII showed a declining trend,but the RII and CI did not,which might indicate that inequality was persistent.Similar results were found in the sensitivity analysis.Conclusions::Despite the declining trend of the mortality rate and the narrowing gap between countries,there were still a large number of children and adolescents dying from NTUIs,and those experiencing social-economic disadvantages remained at high mortality.Embedding the prevention of NTUIs into sustainable development goals might contribute to the progress of reducing death and inequalities,which ensures that no one is left behind.展开更多
The impact of a typical municipal solid waste incinerator （MSWI） on polychlorinated biphenyl （PCB） concentrations in the surrounding soil was studied. Six stack gas samples were taken from the MSWI and 21 soil sam...The impact of a typical municipal solid waste incinerator （MSWI） on polychlorinated biphenyl （PCB） concentrations in the surrounding soil was studied. Six stack gas samples were taken from the MSWI and 21 soil samples were collected from sampling sites between 300 and 1700 m from the MSWI stack. The total （∑PCB） concentrations of dioxin-like （dl） PCBs and indicator PCBs in the stack gas samples were between 3.41 and 34.3 ng/m3, and the corresponding toxic equivalents （TEQs） ranged from 4.45 to 66.9 pg WHO-TEQ/m3, with a mean of 28.6 pg WHO-TEQ/m3. A total of 2.43 g WHO-TEQ of PCBs per year was calculated to be released into the environment from MSWIs in China. The ∑PCB concentrations in the soil samples ranged from 28.0 to 264.4 pg/g, with mean and median values of 127.6 and 127.7 pg/g, respectively, while the TEQ values were between 0.020 and 0.18 pg WHO-TEQ/g, with mean and median values of 0.074 and 0.062 pg WHO-TEQ/g, respectively. Comparing this study with other studies performed around the world suggest that PCB emission from incinerators has a critical influence on PCB concentrations in the surrounding soil. An exponential function equation is proposed, which indicates a clear decline in ∑PCB concentrations with increasing distance from the stack. A contour map created using an ordinary kriging interpolation technique showed that a limited area （1250 m radius） from the stack was clearly influenced by PCB emission from the MSWI.展开更多
Invasive species are considered one of the greatest threats to native ecosystems, second only to habitat loss and frag- mentation. Despite this, the temporal dynamics of invasions are poorly understood, with most stud...Invasive species are considered one of the greatest threats to native ecosystems, second only to habitat loss and frag- mentation. Despite this, the temporal dynamics of invasions are poorly understood, with most studies focusing on a single time point, providing us with only a snapshot of the biology and genetics of the invader. We investigated the invasion of Lord Howe Island by the delicate skink Lampropholis delicata and assessed the introduction history and genetic structure of this species over a 5-year period. Using genetic data taken from 2007, and again in 2011/12, we examined changes in the population genetic struc- ture （whether new haplotypes had been introduced to the island, and shifts in haplotype frequencies） of the species on the island between these two time points. No new haplotypes were introduced to the island between 2007 and 2011/12; however, significant shifts in haplotype frequencies across the island were detected. We conclude that the delicate skink is expanding its range into the southern regions of the island and that the haplotype frequencies on Lord Howe Island are still in a state of highly dynamic flux. Our study highlights the importance of considering invasions as dynamic and studying them in such a way that enable us to better manage their impacts展开更多
We corrected the mistake of Figure 3,and replaced the incorrect images with the correct ones.The“adenovirus”was a typographical error in writing,and should be revised to“lentivirus”.
Security of smart technologies like smart grids and crowd energy systems cannot rely only on technical solutions, humans play a significant role in failure, security culture, information security, cyber security, trus...Security of smart technologies like smart grids and crowd energy systems cannot rely only on technical solutions, humans play a significant role in failure, security culture, information security, cyber security, trust and sharing, and perceptions and concern. This paper investigates security issues in smart technologies and the related role of human failure, whether it is intentional or unintentional.Methods that help reducing this failure are discussed. A human oriented framework for failure reduction is presented in order to enhance security.展开更多
Semi-insulating （SI） GaN is grown using N2 as the nucleation layer （NL） carrier gas combined with an optimized annealing time by metalorganic chemical vapour deposition. Influence of using 1-12 and N2 as the NL ca...Semi-insulating （SI） GaN is grown using N2 as the nucleation layer （NL） carrier gas combined with an optimized annealing time by metalorganic chemical vapour deposition. Influence of using 1-12 and N2 as the NL carrier gas is investigated in our experiment. It is found that the sheet resistance of unintentionally doped GaN can be increased from 10^4 Ω/sq to 10^10 Ω/sq by changing the NL carrier gas from 1-12 to N2 while keeping the other growth parameters to be constant, however crystal quality and roughness of the tilm are degraded unambiguously. This situation can be improved by optimizing the NL annealing time. The high resistance of GaN grown on NL using N2 as the carrier gas is due to higher density of threading dislocations caused by the higher density of nucleation islands and small statistic diameter grain compared to the one using 1-12 as carrier gas. Annealing the NL for an optimized annealing time can decrease the density of threading dislocation and improve the tilm roughness and interface of AlGaN/GaN without degrading the sheet resistance of as-grown GaN signiticantly. High-quality SI GaN is grown after optimizing the annealing time, and AlGaN/GaN high electron mobility transistors are also prepared.展开更多
BACKGROUND Nonadherence is a major problem in the treatment of psychotic disorders.It has been hypothesized that nonadherent patients with schizophrenia are not a homogeneous population and subtypes of nonadherence mi...BACKGROUND Nonadherence is a major problem in the treatment of psychotic disorders.It has been hypothesized that nonadherent patients with schizophrenia are not a homogeneous population and subtypes of nonadherence might exist,but this hypothesis has not been specifically tested.AIM To test the hypothesis of subtypes of nonadherence in schizophrenia and schizoaffective disorder.METHODS This prospective study included 110 consecutively admitted patients diagnosed with schizophrenia or schizoaffective disorder.Assessments were performed at baseline and at 6 mo follow-up after discharge.Sociodemographic,clinical,psychopathological and treatment-related variables were evaluated.Adherence was defined as the concurrence of adherence to antipsychotic treatment and outpatient follow-up during the six-month period.Adherence to antipsychotic treatment was defined as the concurrence of objective and subjective adherence.Sixty-four patients(58%)fulfilled nonadherence criteria at the end of the followup period and were categorized according to their subtype of nonadherence.RESULTS In nonadherent patients(n=64),32(50%)fulfilled criteria of intentional nonadherence,and 32(50%)of unintentional nonadherence(UNA).Unintentional nonadherent patients,as compared to intentional nonadherent patients,are characterized by older age,lower educational level,worse cognitive and negative symptoms,greater severity,worse knowledge of their treatment regimen,greater prevalence of supervision of the treatment,lower number of prior hospitalizations and greater use of nonpsychiatric treatment,anticholinergics and hypnotics.Low educational level(OR=26.1;95%CI:2.819-241),worse treatment knowledge at six months(OR per unit=0.904;95%CI:0.853-0.957)and nonpsychiatric treatment at six months(OR=15.8;95%CI:1.790-139)were independently associated to UNA.CONCLUSION Differentiated subtypes of nonadherence according to intentionality seem to exist in patients with schizophrenia and schizoaffective disorder.Our findings suggest the need for differentiated approach,both in future research and in clinical practice.展开更多
The study has tried to identify whether poor self-rated health and home and neighbourhood environmental problems trigger injuries. The study used data from the Life & Health year 2008 survey, a postal questionnair...The study has tried to identify whether poor self-rated health and home and neighbourhood environmental problems trigger injuries. The study used data from the Life & Health year 2008 survey, a postal questionnaire administered by Statistics Sweden in five administrative regions in central Sweden (Uppsala, S?dermanland, ?rebro, Varmland and V?stmanland). A random sample of 1,060,032 respondents aged 18 - 79 years had participated in the study. ?rebro and Varmland region had the highest proportions of injuries. People at their age between 18 to 24 years—males—tobacco and alcohol addicted had the highest proportions of injuries. Environmental factors such as disturbances in and around home had emerged as major triggering factors for injuries. Physical functional problems such as problem of buying own food, cooking, dressing-up and walking had been emerged as very strong predicting factors of injuries. Policy makers in Sweden could identify the poor neighborhood, disturb living condition through the housing companies and the cooperative housing societies to control injuries and promote safety.展开更多
Introduction: Home accidents (HA) are often unknown in Benin compared to infectious pathologies. The aim of this work was to determine the prevalence and the factors associated with HA in children admitted to the CHUD...Introduction: Home accidents (HA) are often unknown in Benin compared to infectious pathologies. The aim of this work was to determine the prevalence and the factors associated with HA in children admitted to the CHUD-OP. Method: This was a cross-sectional study conducted from August 1<sup>st</sup> to October 31<sup>th</sup> 2021. We studied children aged 0 to 18 who presented with HA to the pediatrics and emergency reception and triage departments at CHUD-OP. We defined HA as “any event occurring inside the home or in the immediate vicinity of the home that resulted in an injury which was not done deliberately. Results: The hospital frequency of HA was 8.4% (61/725). The median age was 5 years with a male to female ratio of 1.6. Trauma was the leading cause of HA (59%) followed by poisoning (23%). Falling was the main mechanism of trauma (80.6%). The toxins causing poisoning were dominated by caustics (28.6%). The age of the children (p = 0.02), the level of education of the mothers (p , and the area they occur (kitchen with p = 0.04 and on the stairs with p = 0.03) were statistically associated with the occurrence of trauma. Conclusion: HA are common among children admitted at CHUD-OP and factors associated with HA are identified. Measures to prevent home accidents among children in the community should be considered.展开更多
Polychlorinated biphenyls(PCBs)were continuously receiving attention after their ban for use and production,owing to significant persistence,transport,and toxicity at trace level.Due to the field data gap of all 209 P...Polychlorinated biphenyls(PCBs)were continuously receiving attention after their ban for use and production,owing to significant persistence,transport,and toxicity at trace level.Due to the field data gap of all 209 PCB congeners in previous studies,the source and environmental migration of lacustrine PCBs were not comprehensively understood.In this study,209 PCB congeners in 277 water and 155 sediment samples collected from China's 23 large lakes across a longitudinal transect(18-45°N)were analyzed.Results showed that the concentrations of S209 PCBs were 0.03e41.04 ng/L and 0.26-163.82 ng/g dry weight in lake water and sediment,respectively.In lake water,the dominant PCB congeners,detected in over 50%of all samples,were PCB 11,PCB 28+31,PCB 41+64+68,PCB 47+48+75,and PCB 51,with contributions to ∑_(209) PCBs as 39.8%,6.6%,3.5%,18.4%,and 6.4%,respectively.Source appor-tionment revealed that major contributions of PCB 11,41+64+68,47+48+75,51,and 209,were mainly from unintentionally produced PCBs(UP-PCBs)while PCB 28+31 and the other congeners from historical PCB commercials.Therefore,the selective congener analysis(excluding UP-PCBs)common in previous lake studies was an omission.Simultaneously,the longitudinal fractionation of PCBs was also found in lake waters,likely caused by the East Asian monsoon.Moreover,fugacity fractions of PCBs between water and sediment indicated their overall equilibrium or net sorption.Overall,PCB 28+31 can be well indicative of PCB migration.This study provides basic information for the migration and transformation of trace toxic persistent organic pollutants.展开更多
Releases of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/PCDFs)from industrial or thermal processes to the aquatic environment are considered small compared to emissions to air today.However,industrial pro...Releases of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/PCDFs)from industrial or thermal processes to the aquatic environment are considered small compared to emissions to air today.However,industrial processes have occasionally released PCDD/PCDFs into local aquatic environments..PCDD/PCDF formation and releases were re-examined based on investigations conducted before the introduction of water quality regulations in Japan.Emphasis was given to PCDD/PCDF formation in various industrial processes such as the manufacture of acetylene and caprolactam.In acetylene production,PCDD/PCDFs are formed in the oxidative process using chlorine to remove impurities,with PCDFs formed with the particular chlorine pattern with 1,2,7,8-TetraCDF,2,3,7,8-TetraCDFs and 1,2,3,4,7,8-HexaCDF as maker congeners and low PCDDs levels.This indicates that acetylene production residues contain organochlorines.In caprolactam production,formation of PCDD/PCDFs in the cyclohexane photonitrosation process has been confirmed and the emission factor for PCDD/PCDF releases to water from for caprolactam manufacture was estimated with an emission factor for releases to the aquatic environment of 0.25±0.04 mgTEQ/t.A range of additional processes with PCDD/PCDF release were also found during the Japanese survey.Overall,the formation processes were placed in two categories:(A)chemical synthesis processes and (B)flue gas treatment of high temperature processes.The final effluent water met the PCDD/PCDF limits by applying advanced treatment for PCDD/PCDF removal such as activated carbon treatment.The survey shows that industrial processes involving elemental chlorine or other processes that facilitate chlorination or use chlorinating chemicals should be assessed and controlled for PCDD/PCDFs and other unintentional POPs releases to water.In such surveys,chemicals from the chlorine and organochlorine industry should also be assessed for PCDD/PCDFs and other unintentional POPs contamination as proposed by the UNEP Toolkit.The current study can contribute to the Stockholm Convention implementation of Article 5 of the Stockholm Convention to take measures to reduce the release of UPOPs from anthropogenic sources with the goal of their continuing minimization and,where feasible,ultimate elimination.展开更多
Dopants and defects are important in semiconductor and magnetic devices. Strategies for controlling doping and defects have been the focus of semiconductor physics research during the past decades and remain critical ...Dopants and defects are important in semiconductor and magnetic devices. Strategies for controlling doping and defects have been the focus of semiconductor physics research during the past decades and remain critical even today. Co-doping is a promising strategy that can be used for effectively tuning the dopant populations, electronic properties, and magnetic properties. It can enhance the solubility of dopants and improve the stability of desired defects. During the past 20 years, significant experimental and theoretical efforts have been devoted to studying the characteristics of co-doping. In this article, we first review the historical development of co-doping. Then, we review a variety of research performed on co-doping, based on the compensating nature of co-dopants. Finally, we review the effects of contamination and surfactants that can explain the general mechanisms of co-doping.展开更多
基金the Deputyship for Research & Innovation, Ministry of Education in Saudi Arabia for funding this research work through the project number 445-9-687。
文摘Manipulating unintentional doping in graphene layers, which is influenced by environmental factors and supporting substrates, is of significant concern for the performance and advancement of graphene-based devices. In this context,laser-induced tuning of charge carriers in graphene facilitates the exploration of graphene's properties in relation to its surroundings and enables laser-assisted functionalization. This has the potential to advance optoelectronic devices that utilize graphene on transparent dielectric substrates, such as Al_(2)O_(3). In this work, laser power(PL) in Raman spectroscopy is used as a convenient contactless tool to manipulate and control unintentional carrier concentration and Fermi level position(EF) in graphene/α-Al_(2)O_(3)(G/Al_(2)O_(3)) under ambient conditions. Samples are annealed at 400℃ for two hours in an(Ar + H_(2)) atmosphere to remove any chemical residues. Analysis of the peak frequency(ω) and full width at half maximum(Γ) of the G and 2D bands show that G/Al_(2)O_(3) layers initially exhibit p-type doping, with EF located at ~100 me V below its Dirac charge-neutral point(DCNP). Increasing P_(L) results in effective carrier manipulation and raises E_F above DCNP. No significant internal stress is produced due to P_(L), as inferred from the strain-sensitive G^(*) band of graphene. Raman analysis of three successive cycles reveals hysteretic behavior from cycle to cycle, which is commonly reported to be limited by the type and density of the existing unintentional doping. Because of the ubiquitous nature of unintentional doping in graphene,manipulating it using contactless laser power to realize the desired graphene properties would be one of the best available practical approaches.
基金supported by the National Natural Science Foundation of China(Grant No.62274084)the Fundamental Research Funds for the Central Universities(Grant No.0210-14380193).
文摘Diamond with silicon vacancies has an important role as a promising single-photon source applicable in the quantum information field.However,in a microwave plasma chemical vapor deposition(MPCVD)system,due to the presence of unintentional silicon doping sources such as quartz windows,the behavior of silicon vacancy formation in silicon-doped diamond is complex.In this work,the underlying mechanism of formation of silicon vacancies by unintentional silicon doping in diamond is investigated from the perspective of growing surface kinetics in a two-gas-flow MPCVD system.This system is equipped with a novel susceptor geometry designed to deliver an additional gas flow directly onto the substrate surface.Increasing the concentration of growth doping substances on the substrate surface thereby enhances the efficiency of silicon vacancy formation in diamond.At the same time,by changing the substrate deposition angle the distribution of gas and plasma on the substrate surface is changed,thereby regulating the concentration and distribution of silicon vacancies formed by unintentional silicon doping.Experimental and computational results demonstrate that the difference in silicon vacancies formed by unintentional silicon doping in diamond depends on the substances present on the substrate surface and the distribution of plasma.
基金This work was supported in part by the National Natural Science Foundation of China under Grant 61701059,Grant 61941114,and Grant 61831002in part by the Fundamental Research Funds for the Central Universities of New Teachers Project,in part by the Basic and Advanced Research Projects of CSTC(No.cstc2019jcyj-zdxmX0008)+2 种基金in part by the Chongqing Science and Technology Innovation Leading Talent Support Program(CSTCCXLJR-C201710,and CSTCCXLJRC201908)in part by Chongqing Technological Innovation and Application Development Projects(cstc2019jscx-msxm1322)in part by the Science and Technology Research Program of Chongqing Municipal Education Commission(Grant No.KJZD-K201900605).
文摘The forking problem plays a key role in the security issue,which is a major concern in the blockchain system.Although many works studied the attack strategy,consensus mechanism,privacy-protecting and security performance analysis,most of them only address the intentional forking caused by a malicious attacker.In fact,without any attacker,unintentional forking still remains due to transmission delay and failure,especially in wireless network scenarios.To this end,this paper investigates the reason for generating unintentional forking and derives the forking probability expression in Wireless Blockchain Networks(WBN).Furthermore,in order to illustrate the unintentional forking on the blockchain system,the performances in terms of resource utilization rate,block generation time,and Transaction Per Second(TPS)are investigated.The numerical results show that the target difficulty of hash algorithm in generating a new block,the delay time of broadcasting,the network scale,and the transmission failure probability would affect the unintentional forking probability significantly,which can provide a reliable basis for avoiding forking to save resource consumption and improving system performance.
基金This work was supported by the Program for Innovative Research Groups of the Hunan Provincial Natural Science Foundation of China(2019JJ10004).
文摘Radio frequency fingerprinting(RFF)is a technology that identifies the specific emitter of a received electromagnetic signal by external measurement of the minuscule hardware-level,device-specific imperfections.The RFF-related information is mainly in the form of unintentional modulation(UIM),which is subtle enough to be effectively imperceptible and is submerged in the intentional modulation(IM).It is necessary to minimize the influence of the IM and expand the slight differences between emitters for successful RFF.This paper proposes a UIM microstructure enlargement(UMME)method based on feature-level adaptive signal decomposition(ASD),accompanied by autocorrelation and cross-correlation analysis.The common IM part is evaluated by analyzing a newly-defined benchmark feature.Three different indexes are used to quantify the similarity,distance,and dependency of the RFF features from different devices.Experiments are conducted based on the real-world signals transmitted from 20 of the same type of radar in the same working mode.The visual image qualitatively shows the magnification of feature differences;different indicators quantitatively describe the changes in features.Compared with the original RFF feature,recognition results based on the Gaussian mixture model(GMM)classifier further validate the effectiveness of the proposed algorithm.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61204017 and 61334002the National Basic Research Program of Chinathe National Science and Technology Major Project of China
文摘AlGaN/GaN high electron mobility transistors （HEMTs） grown on Fe-modulation-doped （MD） and unintentionally doped （UID） GaN buffer layers are investigated and compared. Highly resistive GaN buffers （10^9Ω·cm） are induced by individual mechanisms for the electron traps＇ formation： the Fe MD buffer （sample A） and the UID buffer with high density of edge-type dislocations （7.24×10^9cm^-2, sample B）. The 300K Hall test indicates that the mobility of sample A with Fe doping （2503cm^2V^-1s^-1） is much higher than sample B （1926cm^2V^-1s^-1） due to the decreased scattering effect on the two-dimensional electron gas. HEMT devices are fabricated on the two samples and pulsed I–V measurements are conducted. Device A shows better gate pinch-off characteristics and a higher threshold voltage （-2.63V） compared with device B （-3.71V）. Lower gate leakage current ｜IGS｜ of device A （3.32×10^-7A） is present compared with that of device B （8.29×10^-7A）. When the off-state quiescent points Q_2 （V GQ2=-8V, V DQ2=0V） are on, V th hardly shifts for device A while device B shows ＋0.21V positive threshold voltage shift, resulting from the existence of electron traps associated with the dislocations in the UID-GaN buffer layer under the gate. Under pulsed I–V and transconductance G m–V GS measurement, the device with the Fe MD-doped buffer shows more potential in improving reliability upon off-state stress.
基金supported by a grant from the NWG Macintosh Memorial Fundsupported by a scholarship from the Australian Pain SocietyAustralian Pain Relief Association
文摘The study of brain function in the presence of pain and injury is a rapidly expanding field of experimental research.Clinically,the presence of pain and injury is often accompanied by reports of behavioural change and altered cognition.Even in a highly controlled environment such as the surgical operating theatre postoperative behavioural changes including posttraumatic stress disorder,depression,chronic fatigue,
基金supported by the Youth Science and Technology Innovation Award of National University of Defense Technology (18/19-QNCXJ)the National Science Foundation of China (62271494)
文摘Extensive experiments suggest that kurtosis-based fingerprint features are effective for specific emitter identification (SEI). Nevertheless, the lack of mechanistic explanation restricts the use of fingerprint features to a data-driven technique and fur-ther reduces the adaptability of the technique to other datasets. To address this issue, the mechanism how the phase noise of high-frequency oscillators and the nonlinearity of power ampli-fiers affect the kurtosis of communication signals is investigated. Mathematical models are derived for intentional modulation (IM) and unintentional modulation (UIM). Analysis indicates that the phase noise of high-frequency oscillators and the nonlinearity of power amplifiers affect the kurtosis frequency and amplitude, respectively. A novel SEI method based on frequency and ampli-tude of the signal kurtosis (FA-SK) is further proposed. Simula-tion and real-world experiments validate theoretical analysis and also confirm the efficiency and effectiveness of the proposed method.
文摘During the start-up and unstable combustion periods,even the state-of-the-art incinerators emit polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/PCDF) in stack gases at concentrations that are up to 1000 times higher than normal operation. Therefore,incinerators and other sources with variation of PCDD/PCDF release into air cannot be reliably monitored by the conventional short-term sampling that covers only 0.1%to 0.2%of the yearly operating time.A more comprehensive monitoring regime is required.This paper describes different applications of continuous PCDD/PCDF sampling in some European countries.The cases demonstrate that flexible regimes for continuous sampling can be crafted and applied by governments or regional/local authorities.Such regimes range from a countrywide,continuous requirement for selected facility types(e.g.,waste incinerators) to a facility-specific regime that applies,for example,to new facilities for a defined time period until the facility has demonstrated continuous compliance with regulatory limits. Countries implementing the Stockholm Convention are suggested to evaluate in their Best available technology/Best environmental practice(BAT/BEP) activities the usefulness of long-term sampling by,for example,designating institutes related to the environmental ministry or regional authorities to supervise long-term sampling regimes at relevant facilities in their country/areas,beginning with priority sources(e.g.,facilities used for destruction of persistent organic pollutants(POPs) or hazardous waste processing) . This paper presents and discusses the results of the AMESA long-term monitoring system having demonstrated that in addition to PCDD/PCDF all other unintentionally produced POPs listed in the Stockholm Convention could be supervised.
基金This study was supported by grants from the National Statistical ScientificResearch Program(No.2021LY052)the China Medical Board(21-434 to YS)the National Natural Science Foundation of China(No.82073573).
文摘Background::Non-transport unintentional injuries(NTUIs)are major public concerns,especially among children and adolescents in low-and middle-income countries.With environmental and cognitive changes,a recent systematic description of global trends and regional differences concerning NTUIs is urgently needed for the global agenda of relevant policy-making and intervention target findings.Methods::We used mortality,population,and socio-demographic-index(SDI)data from Global Burden of Disease 2019 to analyze the trends of NTUIs mortality.We applied the slope index of inequality(SII)and relative index of inequality(RII)to measure the absolute and relative inequality between countries and territories.The concentration curve and concentration index(CI)were also used to measure the inequality.We conducted a sensitivity analysis to make our findings credible.Results::In 2019,there were 205,000 deaths due to NTUIs among children and adolescents aged 5 to 24 years,which decreased from 375,000 in 1990.In 2019,the age-standardized mortality rate(ASMR)was 8.13 per 100,000,ranging from the lowest in the Netherlands(0.90 per 100,000)to the highest in the Solomon Islands(29.34 per 100,000).The low-middle SDI group had the highest ASMR of NTUIs,while the low SDI group had the slowest decrease.After excluding the death caused by"exposure to forces of nature"and"other unintentional injuries",drowning accounted for the most deaths in almost every SDI group,gender,and age group,but the major causes of death varied in different subgroups.For example,animal contact was a major cause in low and low-middle SDI groups but less in high SDI groups,while high and high-middle SDI groups had a higher proportion of deaths for foreign body and poisonings.The SII showed a declining trend,but the RII and CI did not,which might indicate that inequality was persistent.Similar results were found in the sensitivity analysis.Conclusions::Despite the declining trend of the mortality rate and the narrowing gap between countries,there were still a large number of children and adolescents dying from NTUIs,and those experiencing social-economic disadvantages remained at high mortality.Embedding the prevention of NTUIs into sustainable development goals might contribute to the progress of reducing death and inequalities,which ensures that no one is left behind.
基金supported by the National Program on Key Basic Research Project (973) of China (No.2011CB201500)the Environmental Public Welfare Projects (No.201209019, 201109001)+1 种基金the National Hightech Research and Development Program (863) of China (No.2011AA060605)the National Natural Science Foundation of China (No.20977099, 21077121)
文摘The impact of a typical municipal solid waste incinerator （MSWI） on polychlorinated biphenyl （PCB） concentrations in the surrounding soil was studied. Six stack gas samples were taken from the MSWI and 21 soil samples were collected from sampling sites between 300 and 1700 m from the MSWI stack. The total （∑PCB） concentrations of dioxin-like （dl） PCBs and indicator PCBs in the stack gas samples were between 3.41 and 34.3 ng/m3, and the corresponding toxic equivalents （TEQs） ranged from 4.45 to 66.9 pg WHO-TEQ/m3, with a mean of 28.6 pg WHO-TEQ/m3. A total of 2.43 g WHO-TEQ of PCBs per year was calculated to be released into the environment from MSWIs in China. The ∑PCB concentrations in the soil samples ranged from 28.0 to 264.4 pg/g, with mean and median values of 127.6 and 127.7 pg/g, respectively, while the TEQ values were between 0.020 and 0.18 pg WHO-TEQ/g, with mean and median values of 0.074 and 0.062 pg WHO-TEQ/g, respectively. Comparing this study with other studies performed around the world suggest that PCB emission from incinerators has a critical influence on PCB concentrations in the surrounding soil. An exponential function equation is proposed, which indicates a clear decline in ∑PCB concentrations with increasing distance from the stack. A contour map created using an ordinary kriging interpolation technique showed that a limited area （1250 m radius） from the stack was clearly influenced by PCB emission from the MSWI.
文摘Invasive species are considered one of the greatest threats to native ecosystems, second only to habitat loss and frag- mentation. Despite this, the temporal dynamics of invasions are poorly understood, with most studies focusing on a single time point, providing us with only a snapshot of the biology and genetics of the invader. We investigated the invasion of Lord Howe Island by the delicate skink Lampropholis delicata and assessed the introduction history and genetic structure of this species over a 5-year period. Using genetic data taken from 2007, and again in 2011/12, we examined changes in the population genetic struc- ture （whether new haplotypes had been introduced to the island, and shifts in haplotype frequencies） of the species on the island between these two time points. No new haplotypes were introduced to the island between 2007 and 2011/12; however, significant shifts in haplotype frequencies across the island were detected. We conclude that the delicate skink is expanding its range into the southern regions of the island and that the haplotype frequencies on Lord Howe Island are still in a state of highly dynamic flux. Our study highlights the importance of considering invasions as dynamic and studying them in such a way that enable us to better manage their impacts
文摘We corrected the mistake of Figure 3,and replaced the incorrect images with the correct ones.The“adenovirus”was a typographical error in writing,and should be revised to“lentivirus”.
基金supported by the by the Canton of Fribourg,Switzerland,through the smart living lab project at the University of Fribourg
文摘Security of smart technologies like smart grids and crowd energy systems cannot rely only on technical solutions, humans play a significant role in failure, security culture, information security, cyber security, trust and sharing, and perceptions and concern. This paper investigates security issues in smart technologies and the related role of human failure, whether it is intentional or unintentional.Methods that help reducing this failure are discussed. A human oriented framework for failure reduction is presented in order to enhance security.
基金Supported by the Knowledge Innovation Programme of Chinese Academy of Sciences, the National Natural Science Foundation of China under Grant Nos 10474126 and 10574148, and the National Key Basic Research Programme of China under Grant No 2002CB311900.
文摘Semi-insulating （SI） GaN is grown using N2 as the nucleation layer （NL） carrier gas combined with an optimized annealing time by metalorganic chemical vapour deposition. Influence of using 1-12 and N2 as the NL carrier gas is investigated in our experiment. It is found that the sheet resistance of unintentionally doped GaN can be increased from 10^4 Ω/sq to 10^10 Ω/sq by changing the NL carrier gas from 1-12 to N2 while keeping the other growth parameters to be constant, however crystal quality and roughness of the tilm are degraded unambiguously. This situation can be improved by optimizing the NL annealing time. The high resistance of GaN grown on NL using N2 as the carrier gas is due to higher density of threading dislocations caused by the higher density of nucleation islands and small statistic diameter grain compared to the one using 1-12 as carrier gas. Annealing the NL for an optimized annealing time can decrease the density of threading dislocation and improve the tilm roughness and interface of AlGaN/GaN without degrading the sheet resistance of as-grown GaN signiticantly. High-quality SI GaN is grown after optimizing the annealing time, and AlGaN/GaN high electron mobility transistors are also prepared.
基金Supported by College of Physicians of Las Palmas,No.I03/19.
文摘BACKGROUND Nonadherence is a major problem in the treatment of psychotic disorders.It has been hypothesized that nonadherent patients with schizophrenia are not a homogeneous population and subtypes of nonadherence might exist,but this hypothesis has not been specifically tested.AIM To test the hypothesis of subtypes of nonadherence in schizophrenia and schizoaffective disorder.METHODS This prospective study included 110 consecutively admitted patients diagnosed with schizophrenia or schizoaffective disorder.Assessments were performed at baseline and at 6 mo follow-up after discharge.Sociodemographic,clinical,psychopathological and treatment-related variables were evaluated.Adherence was defined as the concurrence of adherence to antipsychotic treatment and outpatient follow-up during the six-month period.Adherence to antipsychotic treatment was defined as the concurrence of objective and subjective adherence.Sixty-four patients(58%)fulfilled nonadherence criteria at the end of the followup period and were categorized according to their subtype of nonadherence.RESULTS In nonadherent patients(n=64),32(50%)fulfilled criteria of intentional nonadherence,and 32(50%)of unintentional nonadherence(UNA).Unintentional nonadherent patients,as compared to intentional nonadherent patients,are characterized by older age,lower educational level,worse cognitive and negative symptoms,greater severity,worse knowledge of their treatment regimen,greater prevalence of supervision of the treatment,lower number of prior hospitalizations and greater use of nonpsychiatric treatment,anticholinergics and hypnotics.Low educational level(OR=26.1;95%CI:2.819-241),worse treatment knowledge at six months(OR per unit=0.904;95%CI:0.853-0.957)and nonpsychiatric treatment at six months(OR=15.8;95%CI:1.790-139)were independently associated to UNA.CONCLUSION Differentiated subtypes of nonadherence according to intentionality seem to exist in patients with schizophrenia and schizoaffective disorder.Our findings suggest the need for differentiated approach,both in future research and in clinical practice.
文摘The study has tried to identify whether poor self-rated health and home and neighbourhood environmental problems trigger injuries. The study used data from the Life & Health year 2008 survey, a postal questionnaire administered by Statistics Sweden in five administrative regions in central Sweden (Uppsala, S?dermanland, ?rebro, Varmland and V?stmanland). A random sample of 1,060,032 respondents aged 18 - 79 years had participated in the study. ?rebro and Varmland region had the highest proportions of injuries. People at their age between 18 to 24 years—males—tobacco and alcohol addicted had the highest proportions of injuries. Environmental factors such as disturbances in and around home had emerged as major triggering factors for injuries. Physical functional problems such as problem of buying own food, cooking, dressing-up and walking had been emerged as very strong predicting factors of injuries. Policy makers in Sweden could identify the poor neighborhood, disturb living condition through the housing companies and the cooperative housing societies to control injuries and promote safety.
文摘Introduction: Home accidents (HA) are often unknown in Benin compared to infectious pathologies. The aim of this work was to determine the prevalence and the factors associated with HA in children admitted to the CHUD-OP. Method: This was a cross-sectional study conducted from August 1<sup>st</sup> to October 31<sup>th</sup> 2021. We studied children aged 0 to 18 who presented with HA to the pediatrics and emergency reception and triage departments at CHUD-OP. We defined HA as “any event occurring inside the home or in the immediate vicinity of the home that resulted in an injury which was not done deliberately. Results: The hospital frequency of HA was 8.4% (61/725). The median age was 5 years with a male to female ratio of 1.6. Trauma was the leading cause of HA (59%) followed by poisoning (23%). Falling was the main mechanism of trauma (80.6%). The toxins causing poisoning were dominated by caustics (28.6%). The age of the children (p = 0.02), the level of education of the mothers (p , and the area they occur (kitchen with p = 0.04 and on the stairs with p = 0.03) were statistically associated with the occurrence of trauma. Conclusion: HA are common among children admitted at CHUD-OP and factors associated with HA are identified. Measures to prevent home accidents among children in the community should be considered.
基金supported by the special program for the Basic Work of Science and Technology(2015FY110900-6).
文摘Polychlorinated biphenyls(PCBs)were continuously receiving attention after their ban for use and production,owing to significant persistence,transport,and toxicity at trace level.Due to the field data gap of all 209 PCB congeners in previous studies,the source and environmental migration of lacustrine PCBs were not comprehensively understood.In this study,209 PCB congeners in 277 water and 155 sediment samples collected from China's 23 large lakes across a longitudinal transect(18-45°N)were analyzed.Results showed that the concentrations of S209 PCBs were 0.03e41.04 ng/L and 0.26-163.82 ng/g dry weight in lake water and sediment,respectively.In lake water,the dominant PCB congeners,detected in over 50%of all samples,were PCB 11,PCB 28+31,PCB 41+64+68,PCB 47+48+75,and PCB 51,with contributions to ∑_(209) PCBs as 39.8%,6.6%,3.5%,18.4%,and 6.4%,respectively.Source appor-tionment revealed that major contributions of PCB 11,41+64+68,47+48+75,51,and 209,were mainly from unintentionally produced PCBs(UP-PCBs)while PCB 28+31 and the other congeners from historical PCB commercials.Therefore,the selective congener analysis(excluding UP-PCBs)common in previous lake studies was an omission.Simultaneously,the longitudinal fractionation of PCBs was also found in lake waters,likely caused by the East Asian monsoon.Moreover,fugacity fractions of PCBs between water and sediment indicated their overall equilibrium or net sorption.Overall,PCB 28+31 can be well indicative of PCB migration.This study provides basic information for the migration and transformation of trace toxic persistent organic pollutants.
文摘Releases of polychlorinated dibenzo-p-dioxins and dibenzofurans(PCDD/PCDFs)from industrial or thermal processes to the aquatic environment are considered small compared to emissions to air today.However,industrial processes have occasionally released PCDD/PCDFs into local aquatic environments..PCDD/PCDF formation and releases were re-examined based on investigations conducted before the introduction of water quality regulations in Japan.Emphasis was given to PCDD/PCDF formation in various industrial processes such as the manufacture of acetylene and caprolactam.In acetylene production,PCDD/PCDFs are formed in the oxidative process using chlorine to remove impurities,with PCDFs formed with the particular chlorine pattern with 1,2,7,8-TetraCDF,2,3,7,8-TetraCDFs and 1,2,3,4,7,8-HexaCDF as maker congeners and low PCDDs levels.This indicates that acetylene production residues contain organochlorines.In caprolactam production,formation of PCDD/PCDFs in the cyclohexane photonitrosation process has been confirmed and the emission factor for PCDD/PCDF releases to water from for caprolactam manufacture was estimated with an emission factor for releases to the aquatic environment of 0.25±0.04 mgTEQ/t.A range of additional processes with PCDD/PCDF release were also found during the Japanese survey.Overall,the formation processes were placed in two categories:(A)chemical synthesis processes and (B)flue gas treatment of high temperature processes.The final effluent water met the PCDD/PCDF limits by applying advanced treatment for PCDD/PCDF removal such as activated carbon treatment.The survey shows that industrial processes involving elemental chlorine or other processes that facilitate chlorination or use chlorinating chemicals should be assessed and controlled for PCDD/PCDFs and other unintentional POPs releases to water.In such surveys,chemicals from the chlorine and organochlorine industry should also be assessed for PCDD/PCDFs and other unintentional POPs contamination as proposed by the UNEP Toolkit.The current study can contribute to the Stockholm Convention implementation of Article 5 of the Stockholm Convention to take measures to reduce the release of UPOPs from anthropogenic sources with the goal of their continuing minimization and,where feasible,ultimate elimination.
文摘Dopants and defects are important in semiconductor and magnetic devices. Strategies for controlling doping and defects have been the focus of semiconductor physics research during the past decades and remain critical even today. Co-doping is a promising strategy that can be used for effectively tuning the dopant populations, electronic properties, and magnetic properties. It can enhance the solubility of dopants and improve the stability of desired defects. During the past 20 years, significant experimental and theoretical efforts have been devoted to studying the characteristics of co-doping. In this article, we first review the historical development of co-doping. Then, we review a variety of research performed on co-doping, based on the compensating nature of co-dopants. Finally, we review the effects of contamination and surfactants that can explain the general mechanisms of co-doping.
