BACKGROUND:Chlorfenapyr is used to kill insects that are resistant to organophosphorus insecticides.Chlorfenapyr poisoning has a high mortality rate and is difficult to treat.This article aims to review the mechanisms...BACKGROUND:Chlorfenapyr is used to kill insects that are resistant to organophosphorus insecticides.Chlorfenapyr poisoning has a high mortality rate and is difficult to treat.This article aims to review the mechanisms,clinical presentations,and treatment strategies for chlorfenapyr poisoning.DATA RESOURCES:We conducted a review of the literature using PubMed,Web of Science,and SpringerLink from their beginnings to the end of October 2023.The inclusion criteria were systematic reviews,clinical guidelines,retrospective studies,and case reports on chlorfenapyr poisoning that focused on its mechanisms,clinical presentations,and treatment strategies.The references in the included studies were also examined to identify additional sources.RESULTS:We included 57 studies in this review.Chlorfenapyr can be degraded into tralopyril,which is more toxic and reduces energy production by inhibiting the conversion of adenosine diphosphate to adenosine triphosphate.High fever and altered mental status are characteristic clinical presentations of chlorfenapyr poisoning.Once it occurs,respiratory failure occurs immediately,ultimately leading to cardiac arrest and death.Chlorfenapyr poisoning is diflcult to treat,and there is no specific antidote.CONCLUSION:Chlorfenapyr is a new pyrrole pesticide.Although it has been identified as a moderately toxic pesticide by the World Health Organization(WHO),the mortality rate of poisoned patients is extremely high.There is no specific antidote for chlorfenapyr poisoning.Therefore,based on the literature review,future efforts to explore rapid and effective detoxification methods,reconstitute intracellular oxidative phosphorylation couplings,identify early biomarkers of chlorfenapyr poisoning,and block the conversion of chlorfenapyr to tralopyril may be helpful for emergency physicians in the diagnosis and treatment of this disease.展开更多
BACKGROUND:In clinical practice,some patients might not be able or unwilling to provide a thorough history of medication and poison exposure.The aim of this study was to use toxicological analysis to examine the clini...BACKGROUND:In clinical practice,some patients might not be able or unwilling to provide a thorough history of medication and poison exposure.The aim of this study was to use toxicological analysis to examine the clinical characteristics of patients with acute poisoning whose exposure history was uncertain from a toxicological analysis perspective.METHODS:This was a retrospective and descriptive study from an institute of poisoning.Patient registration information and test reports spanning the period from April 1,2020 to March 31,2022,were obtained.Patients with uncertain exposure histories and who underwent toxicological analysis were included.Clinical manifestations and categories of toxics were analyzed.RESULTS:Among the 195 patients with positive toxicological analysis results,the main causes of uncertain exposure history was disturbance of consciousness(62.6%),unawareness(23.6%)and unwillingness or lack of cooperation(13.8%).The predominant clinical manifestations were disturbed consciousness(62.6%),followed by vomiting and nausea(14.4%)and liver function abnormalities(8.7%).A comparison of clinical manifestations between patients with positive and negative(n=99)toxicological analyses results revealed significantly different proportions of disturbances in consciousness(63%vs.21%),dizziness(1.5%vs.5.1%),multi-organ failure(1.5%vs.7.1%),and local pain(0 vs 4%).The main categories of substances involved were psychiatric medications(23.1%),sedatives(20.5%),insecticides(13.8%),and herbicides(12.8%).CONCLUSION:The clinical manifestations of acute poisoning in patients with an uncertain exposure history are diverse and nonspecific,and toxicological analysis plays a pivotal role in the diagnosis and differential diagnosis of such patients.展开更多
Pesticide poisoning is one of the most common diseases in the emergency department, characterized by rapid changes in condition, a high misdiagnosis rate, and a poor prognosis. Measures for early removal of poisons ar...Pesticide poisoning is one of the most common diseases in the emergency department, characterized by rapid changes in condition, a high misdiagnosis rate, and a poor prognosis. Measures for early removal of poisons are crucial, and gastric lavage is one of the important measures. Regarding the post-gastric lavage effect, abdominal CT scanning has an important application value in the assessment of the gastric lavage effect after pesticide poisoning.展开更多
Bayesian networks are a powerful class of graphical decision models used to represent causal relationships among variables.However,the reliability and integrity of learned Bayesian network models are highly dependent ...Bayesian networks are a powerful class of graphical decision models used to represent causal relationships among variables.However,the reliability and integrity of learned Bayesian network models are highly dependent on the quality of incoming data streams.One of the primary challenges with Bayesian networks is their vulnerability to adversarial data poisoning attacks,wherein malicious data is injected into the training dataset to negatively influence the Bayesian network models and impair their performance.In this research paper,we propose an efficient framework for detecting data poisoning attacks against Bayesian network structure learning algorithms.Our framework utilizes latent variables to quantify the amount of belief between every two nodes in each causal model over time.We use our innovative methodology to tackle an important issue with data poisoning assaults in the context of Bayesian networks.With regard to four different forms of data poisoning attacks,we specifically aim to strengthen the security and dependability of Bayesian network structure learning techniques,such as the PC algorithm.By doing this,we explore the complexity of this area and offer workablemethods for identifying and reducing these sneaky dangers.Additionally,our research investigates one particular use case,the“Visit to Asia Network.”The practical consequences of using uncertainty as a way to spot cases of data poisoning are explored in this inquiry,which is of utmost relevance.Our results demonstrate the promising efficacy of latent variables in detecting and mitigating the threat of data poisoning attacks.Additionally,our proposed latent-based framework proves to be sensitive in detecting malicious data poisoning attacks in the context of stream data.展开更多
BACKGROUND Most species of aconite contain highly toxic aconitines,the oral ingestion of which can be fatal,primarily because they cause ventricular arrhythmias.We describe a case of severe aconite poisoning that was ...BACKGROUND Most species of aconite contain highly toxic aconitines,the oral ingestion of which can be fatal,primarily because they cause ventricular arrhythmias.We describe a case of severe aconite poisoning that was successfully treated through venoarterial extracorporeal membrane oxygenation(VA-ECMO)and in which detailed toxicological analyses of the aconite roots and biological samples were performed using liquid chromatography-tandem mass spectrometry(LC-MS/MS).CASE SUMMARY A 23-year-old male presented to the emergency room with circulatory collapse and ventricular arrhythmia after ingesting approximately half of a root labeled,“Aconitum japonicum Thunb”.Two hours after arrival,VA-ECMO was initiated as circulatory collapse became refractory to antiarrhythmics and vasopressors.Nine hours after arrival,an electrocardiogram revealed a return to sinus rhythm.The patient was weaned off VA-ECMO and the ventilator on hospital days 3 and 5,respectively.On hospital day 15,he was transferred to a psychiatric hospital.The other half of the root and his biological samples were toxicologically analyzed using LC-MS/MS,revealing 244.3 mg/kg of aconitine and 24.7 mg/kg of mesaconitine in the root.Serum on admission contained 1.50 ng/mL of aconitine.Beyond hospital day 2,neither were detected.Urine on admission showed 149.09 ng/mL of aconitine and 3.59 ng/mL of mesaconitine,but these rapidly decreased after hospital day 3.CONCLUSION The key to saving the life of a patient with severe aconite poisoning is to introduce VA-ECMO as soon as possible.展开更多
Rationale:Multi-organ failure is a symptom of paraquat poisoning,resulting in high mortality and morbidity rates.Though paraquat is widely available,poisoning through inhalation is rare.Patient’s Concern:A 37-year-ol...Rationale:Multi-organ failure is a symptom of paraquat poisoning,resulting in high mortality and morbidity rates.Though paraquat is widely available,poisoning through inhalation is rare.Patient’s Concern:A 37-year-old male reported to the emergency department with complaints of vomiting after an alleged history of inhalation of paraquat while at work.Diagnosis:Paraquat poisoning.Interventions:Supportive management along with multiple sessions of hemodialysis.Outcomes:Renal complications caused by paraquat were improved after multiple sessions of hemodialysis.However,the patient developed respiratory complications and later due to persistent hypoxemia and non-responsive to supportive therapy,he succumbed to his illness.Lessons:Acute kidney injury is a complication of paraquat poisoning.However,kidney involvement with the inhalational mode is rare.It is caused by reduction and oxidation cycles,as well as the formation of reactive oxygen species,necessitating hemodialysis as the treatment.Without a clear history,a specific clinical trait,or a diagnostic test,diagnosis can be difficult.Our case thus highlights the inhaled paraquat poisoning,presenting with acute kidney injury with late respiratory impairment as a consequence.展开更多
BACKGROUND This report delves into the diagnostic and therapeutic journey undertaken by a patient with high-dose cantharidin poisoning and multiorgan dysfunction syndrome(MODS).Particular emphasis is placed on the com...BACKGROUND This report delves into the diagnostic and therapeutic journey undertaken by a patient with high-dose cantharidin poisoning and multiorgan dysfunction syndrome(MODS).Particular emphasis is placed on the comprehensive elucidation of the clinical manifestations of high-dose cantharidin poisoning,the intricate path to diagnosis,and the exploration of potential underlying mechanisms.CASE SUMMARY A patient taking 10 g of cantharidin powder orally subsequently developed MODS.The patient was treated with supportive care,fluid hydration and antibiotics,and hemoperfusion and hemofiltration therapy for 24 h and successfully recovered 8 d after hospital admission.Cantharidin poisoning can cause lifethreatening MODS and is rare clinically.This case underscores the challenge in diagnosis and highlights the need for early clinical differentiation to facilitate accurate assessment and prompt intervention.CONCLUSION This article has reported and analyzed the clinical data,diagnosis,treatment,and prognosis of a case of high-dose cantharidin poisoning resulting in MODS and reviewed the relevant literature to improve the clinical understanding of this rare condition.展开更多
Cyanide poisoning is one of the most dangerous poisonings, and it can be absorbed into the body through the mouth, inhalation and through the skin. A 32-year-old female patient was admitted to our poison control cente...Cyanide poisoning is one of the most dangerous poisonings, and it can be absorbed into the body through the mouth, inhalation and through the skin. A 32-year-old female patient was admitted to our poison control center because of high fever, severe vomiting, and seizures. Physical examination found that the patient was drowsy, had a high fever of 40 degrees Celsius, pulse of 140 beats/minute, and increased tendon and bone reflexes. Exploiting the patient’s information, it was discovered that the patient bought Cyanide to drink with the intention of committing suicide. The patient was quickly treated with gastric lavage and activated charcoal. Echocardiography recorded EF: 35%, reduced movement of the entire myocardium. CK blood test: 4562 U/L. The patient’s condition rapidly deteriorated and the patient was made ECMO, IHD and CVVHDF. After 3 days of treatment, the patient’s condition did not improve, so the family asked for the patient to go home. This article aims to describe the rapidly progressing and severe damage to the heart and muscles of patients with cyanide poisoning.展开更多
A ZrV_(2)alloy is typically susceptible to poisoning by impurity gases,which causes a considerable reduction in the hydrogen storage properties of the alloy.In this study,the adsorption characteristics of oxygen on Zr...A ZrV_(2)alloy is typically susceptible to poisoning by impurity gases,which causes a considerable reduction in the hydrogen storage properties of the alloy.In this study,the adsorption characteristics of oxygen on ZrV_(2)surfaces doped with Hf,Ti,and Pd are investigated,and the effect of oxygen on the hydrogen storage performance of the alloy was discussed.Subsequently,the adsorption energy,bond-length change,density of states,and differential charge density of the alloy before and after doping are analyzed using the first-principles method.The theoretical results show that Ti doping has a limited effect on the adsorption of oxygen atoms on the ZrV_(2)surface,whereas Hf doping decreases the adsorption energy of oxygen on the ZrV_(2)surface.Oxygen atoms are more difficult to adsorb at most adsorption sites on Pd-substituting surfaces,which indicates that Pd has the best anti-poisoning properties,followed by Hf.The analysis of the differential charge density and partial density of states show that the electron interaction between the oxygen atom and surface atom of the alloys is weakened,and the total energy is reduced after Hf and Pd doping.Based on theoretical calculations,the hydrogen absorption kinetics of ZrV_(2),Zr_(0.9)Hf_(0.1)V_(2),and Zr(V_(0.9)Pd_(0.1))_(2) alloys are studied in a hydrogen-oxygen mixture of 0.5 vol%O_(2) at 25℃.The experimental results show that the hydrogen storage capacities of ZrV_(2),Zr_(0.9)Hf_(0.1)V_(2),and Zr(V_(0.9)Pd_(0.1))_(2) decrease to 19%,69%,and 80%of their original values,respectively.The order of alloy resistance to 0.5 vol%O_(2) poisoning is Zr(V_(0.9)Pd_(0.1))_(2)>Zr_(0.9)Hf_(0.1)V_(2)>ZrV_(2).Pd retains its original hydrogen absorption performance to a greater extent than undoped surfaces,and it has the strongest resistance to poisoning,which is consistent with previous theoretical calculations.展开更多
This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both...This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both Cu-SAPO-34 and Cu-ZSM-5. The catalytic activities of fresh, aged and poisoned samples were tested in ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) of NO<sub>x</sub> conditions. The XRD, TG and N<sub>2</sub>-desorption results showed that the structures of the Cu-SAPO-34 and Cu-ZSM-5 remained intact after 750˚C hydrothermally aged, SO<sub>2</sub> and propene poisoned. After hydrothermal aging at 750˚C for 12 h, the NO reduction performance of Cu-ZSM-5 was significantly reduced at lower temperatures, while that of Cu-SAPO-34 was less affected. Moreover, Cu-SAPO-34 catalyst showed high NO conversion with SO<sub>2</sub> or propene compared to Cu-ZSM-5. However, Cu-ZSM-5 showed a larger drop in catalytic activity with SO<sub>2</sub> or propene compared to Cu-SAPO-34 catalyst. The H<sub>2</sub>-TPR results showed that Cu<sup>2 </sup> ions could be reduced to Cu<sup> </sup> and Cu<sup>0</sup> for Cu-ZSM-5, while no significant transformation of copper species was observed for Cu-SAPO-34. Meanwhile, the UV-vis DRS results showed that CuO species were formed in Cu-ZSM-5, while little changes were observed for the Cu-SAPO-34. Cu-SAPO-34 showed high sulfur and hydrocarbon poison resistance compared to Cu-ZSM-5. In summary, Cu-SAPO-34 with small-pore zeolite showed higher hydrothermal stability and better hydrocarbon and sulfur poison resistant than Cu-ZSM-5 with medium-pore.展开更多
基金supported by the Research Foundation of Ningbo No.2 Hospital (2023HMKY49)Ningbo Key Support Medical Discipline (2022-F16)。
文摘BACKGROUND:Chlorfenapyr is used to kill insects that are resistant to organophosphorus insecticides.Chlorfenapyr poisoning has a high mortality rate and is difficult to treat.This article aims to review the mechanisms,clinical presentations,and treatment strategies for chlorfenapyr poisoning.DATA RESOURCES:We conducted a review of the literature using PubMed,Web of Science,and SpringerLink from their beginnings to the end of October 2023.The inclusion criteria were systematic reviews,clinical guidelines,retrospective studies,and case reports on chlorfenapyr poisoning that focused on its mechanisms,clinical presentations,and treatment strategies.The references in the included studies were also examined to identify additional sources.RESULTS:We included 57 studies in this review.Chlorfenapyr can be degraded into tralopyril,which is more toxic and reduces energy production by inhibiting the conversion of adenosine diphosphate to adenosine triphosphate.High fever and altered mental status are characteristic clinical presentations of chlorfenapyr poisoning.Once it occurs,respiratory failure occurs immediately,ultimately leading to cardiac arrest and death.Chlorfenapyr poisoning is diflcult to treat,and there is no specific antidote.CONCLUSION:Chlorfenapyr is a new pyrrole pesticide.Although it has been identified as a moderately toxic pesticide by the World Health Organization(WHO),the mortality rate of poisoned patients is extremely high.There is no specific antidote for chlorfenapyr poisoning.Therefore,based on the literature review,future efforts to explore rapid and effective detoxification methods,reconstitute intracellular oxidative phosphorylation couplings,identify early biomarkers of chlorfenapyr poisoning,and block the conversion of chlorfenapyr to tralopyril may be helpful for emergency physicians in the diagnosis and treatment of this disease.
基金supported by National Natural Science Foundation of China(82172184)。
文摘BACKGROUND:In clinical practice,some patients might not be able or unwilling to provide a thorough history of medication and poison exposure.The aim of this study was to use toxicological analysis to examine the clinical characteristics of patients with acute poisoning whose exposure history was uncertain from a toxicological analysis perspective.METHODS:This was a retrospective and descriptive study from an institute of poisoning.Patient registration information and test reports spanning the period from April 1,2020 to March 31,2022,were obtained.Patients with uncertain exposure histories and who underwent toxicological analysis were included.Clinical manifestations and categories of toxics were analyzed.RESULTS:Among the 195 patients with positive toxicological analysis results,the main causes of uncertain exposure history was disturbance of consciousness(62.6%),unawareness(23.6%)and unwillingness or lack of cooperation(13.8%).The predominant clinical manifestations were disturbed consciousness(62.6%),followed by vomiting and nausea(14.4%)and liver function abnormalities(8.7%).A comparison of clinical manifestations between patients with positive and negative(n=99)toxicological analyses results revealed significantly different proportions of disturbances in consciousness(63%vs.21%),dizziness(1.5%vs.5.1%),multi-organ failure(1.5%vs.7.1%),and local pain(0 vs 4%).The main categories of substances involved were psychiatric medications(23.1%),sedatives(20.5%),insecticides(13.8%),and herbicides(12.8%).CONCLUSION:The clinical manifestations of acute poisoning in patients with an uncertain exposure history are diverse and nonspecific,and toxicological analysis plays a pivotal role in the diagnosis and differential diagnosis of such patients.
文摘Pesticide poisoning is one of the most common diseases in the emergency department, characterized by rapid changes in condition, a high misdiagnosis rate, and a poor prognosis. Measures for early removal of poisons are crucial, and gastric lavage is one of the important measures. Regarding the post-gastric lavage effect, abdominal CT scanning has an important application value in the assessment of the gastric lavage effect after pesticide poisoning.
文摘Bayesian networks are a powerful class of graphical decision models used to represent causal relationships among variables.However,the reliability and integrity of learned Bayesian network models are highly dependent on the quality of incoming data streams.One of the primary challenges with Bayesian networks is their vulnerability to adversarial data poisoning attacks,wherein malicious data is injected into the training dataset to negatively influence the Bayesian network models and impair their performance.In this research paper,we propose an efficient framework for detecting data poisoning attacks against Bayesian network structure learning algorithms.Our framework utilizes latent variables to quantify the amount of belief between every two nodes in each causal model over time.We use our innovative methodology to tackle an important issue with data poisoning assaults in the context of Bayesian networks.With regard to four different forms of data poisoning attacks,we specifically aim to strengthen the security and dependability of Bayesian network structure learning techniques,such as the PC algorithm.By doing this,we explore the complexity of this area and offer workablemethods for identifying and reducing these sneaky dangers.Additionally,our research investigates one particular use case,the“Visit to Asia Network.”The practical consequences of using uncertainty as a way to spot cases of data poisoning are explored in this inquiry,which is of utmost relevance.Our results demonstrate the promising efficacy of latent variables in detecting and mitigating the threat of data poisoning attacks.Additionally,our proposed latent-based framework proves to be sensitive in detecting malicious data poisoning attacks in the context of stream data.
文摘BACKGROUND Most species of aconite contain highly toxic aconitines,the oral ingestion of which can be fatal,primarily because they cause ventricular arrhythmias.We describe a case of severe aconite poisoning that was successfully treated through venoarterial extracorporeal membrane oxygenation(VA-ECMO)and in which detailed toxicological analyses of the aconite roots and biological samples were performed using liquid chromatography-tandem mass spectrometry(LC-MS/MS).CASE SUMMARY A 23-year-old male presented to the emergency room with circulatory collapse and ventricular arrhythmia after ingesting approximately half of a root labeled,“Aconitum japonicum Thunb”.Two hours after arrival,VA-ECMO was initiated as circulatory collapse became refractory to antiarrhythmics and vasopressors.Nine hours after arrival,an electrocardiogram revealed a return to sinus rhythm.The patient was weaned off VA-ECMO and the ventilator on hospital days 3 and 5,respectively.On hospital day 15,he was transferred to a psychiatric hospital.The other half of the root and his biological samples were toxicologically analyzed using LC-MS/MS,revealing 244.3 mg/kg of aconitine and 24.7 mg/kg of mesaconitine in the root.Serum on admission contained 1.50 ng/mL of aconitine.Beyond hospital day 2,neither were detected.Urine on admission showed 149.09 ng/mL of aconitine and 3.59 ng/mL of mesaconitine,but these rapidly decreased after hospital day 3.CONCLUSION The key to saving the life of a patient with severe aconite poisoning is to introduce VA-ECMO as soon as possible.
文摘Rationale:Multi-organ failure is a symptom of paraquat poisoning,resulting in high mortality and morbidity rates.Though paraquat is widely available,poisoning through inhalation is rare.Patient’s Concern:A 37-year-old male reported to the emergency department with complaints of vomiting after an alleged history of inhalation of paraquat while at work.Diagnosis:Paraquat poisoning.Interventions:Supportive management along with multiple sessions of hemodialysis.Outcomes:Renal complications caused by paraquat were improved after multiple sessions of hemodialysis.However,the patient developed respiratory complications and later due to persistent hypoxemia and non-responsive to supportive therapy,he succumbed to his illness.Lessons:Acute kidney injury is a complication of paraquat poisoning.However,kidney involvement with the inhalational mode is rare.It is caused by reduction and oxidation cycles,as well as the formation of reactive oxygen species,necessitating hemodialysis as the treatment.Without a clear history,a specific clinical trait,or a diagnostic test,diagnosis can be difficult.Our case thus highlights the inhaled paraquat poisoning,presenting with acute kidney injury with late respiratory impairment as a consequence.
基金Supported by Jilin Province Science and Technology Agency Project,No.20210101350JCProject of Jilin Provincial Finance Department,No.JLSWSRCZX2023-60Beijing iGandan Foundation Fund for Artificial Liver,No.iGandanF-1082023-RGG025.
文摘BACKGROUND This report delves into the diagnostic and therapeutic journey undertaken by a patient with high-dose cantharidin poisoning and multiorgan dysfunction syndrome(MODS).Particular emphasis is placed on the comprehensive elucidation of the clinical manifestations of high-dose cantharidin poisoning,the intricate path to diagnosis,and the exploration of potential underlying mechanisms.CASE SUMMARY A patient taking 10 g of cantharidin powder orally subsequently developed MODS.The patient was treated with supportive care,fluid hydration and antibiotics,and hemoperfusion and hemofiltration therapy for 24 h and successfully recovered 8 d after hospital admission.Cantharidin poisoning can cause lifethreatening MODS and is rare clinically.This case underscores the challenge in diagnosis and highlights the need for early clinical differentiation to facilitate accurate assessment and prompt intervention.CONCLUSION This article has reported and analyzed the clinical data,diagnosis,treatment,and prognosis of a case of high-dose cantharidin poisoning resulting in MODS and reviewed the relevant literature to improve the clinical understanding of this rare condition.
文摘Cyanide poisoning is one of the most dangerous poisonings, and it can be absorbed into the body through the mouth, inhalation and through the skin. A 32-year-old female patient was admitted to our poison control center because of high fever, severe vomiting, and seizures. Physical examination found that the patient was drowsy, had a high fever of 40 degrees Celsius, pulse of 140 beats/minute, and increased tendon and bone reflexes. Exploiting the patient’s information, it was discovered that the patient bought Cyanide to drink with the intention of committing suicide. The patient was quickly treated with gastric lavage and activated charcoal. Echocardiography recorded EF: 35%, reduced movement of the entire myocardium. CK blood test: 4562 U/L. The patient’s condition rapidly deteriorated and the patient was made ECMO, IHD and CVVHDF. After 3 days of treatment, the patient’s condition did not improve, so the family asked for the patient to go home. This article aims to describe the rapidly progressing and severe damage to the heart and muscles of patients with cyanide poisoning.
基金the Youth Innovation Promotion Association,Chinese Academy of Science(No.2019263)the National Natural Science Foundation of China(No.12105355).
文摘A ZrV_(2)alloy is typically susceptible to poisoning by impurity gases,which causes a considerable reduction in the hydrogen storage properties of the alloy.In this study,the adsorption characteristics of oxygen on ZrV_(2)surfaces doped with Hf,Ti,and Pd are investigated,and the effect of oxygen on the hydrogen storage performance of the alloy was discussed.Subsequently,the adsorption energy,bond-length change,density of states,and differential charge density of the alloy before and after doping are analyzed using the first-principles method.The theoretical results show that Ti doping has a limited effect on the adsorption of oxygen atoms on the ZrV_(2)surface,whereas Hf doping decreases the adsorption energy of oxygen on the ZrV_(2)surface.Oxygen atoms are more difficult to adsorb at most adsorption sites on Pd-substituting surfaces,which indicates that Pd has the best anti-poisoning properties,followed by Hf.The analysis of the differential charge density and partial density of states show that the electron interaction between the oxygen atom and surface atom of the alloys is weakened,and the total energy is reduced after Hf and Pd doping.Based on theoretical calculations,the hydrogen absorption kinetics of ZrV_(2),Zr_(0.9)Hf_(0.1)V_(2),and Zr(V_(0.9)Pd_(0.1))_(2) alloys are studied in a hydrogen-oxygen mixture of 0.5 vol%O_(2) at 25℃.The experimental results show that the hydrogen storage capacities of ZrV_(2),Zr_(0.9)Hf_(0.1)V_(2),and Zr(V_(0.9)Pd_(0.1))_(2) decrease to 19%,69%,and 80%of their original values,respectively.The order of alloy resistance to 0.5 vol%O_(2) poisoning is Zr(V_(0.9)Pd_(0.1))_(2)>Zr_(0.9)Hf_(0.1)V_(2)>ZrV_(2).Pd retains its original hydrogen absorption performance to a greater extent than undoped surfaces,and it has the strongest resistance to poisoning,which is consistent with previous theoretical calculations.
文摘This study was aimed to investigate the effects of hydrothermal aging, propene and SO<sub>2</sub> poisoning on the ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) performance of both Cu-SAPO-34 and Cu-ZSM-5. The catalytic activities of fresh, aged and poisoned samples were tested in ammonia-selective catalytic reduction (NH<sub>3</sub>-SCR) of NO<sub>x</sub> conditions. The XRD, TG and N<sub>2</sub>-desorption results showed that the structures of the Cu-SAPO-34 and Cu-ZSM-5 remained intact after 750˚C hydrothermally aged, SO<sub>2</sub> and propene poisoned. After hydrothermal aging at 750˚C for 12 h, the NO reduction performance of Cu-ZSM-5 was significantly reduced at lower temperatures, while that of Cu-SAPO-34 was less affected. Moreover, Cu-SAPO-34 catalyst showed high NO conversion with SO<sub>2</sub> or propene compared to Cu-ZSM-5. However, Cu-ZSM-5 showed a larger drop in catalytic activity with SO<sub>2</sub> or propene compared to Cu-SAPO-34 catalyst. The H<sub>2</sub>-TPR results showed that Cu<sup>2 </sup> ions could be reduced to Cu<sup> </sup> and Cu<sup>0</sup> for Cu-ZSM-5, while no significant transformation of copper species was observed for Cu-SAPO-34. Meanwhile, the UV-vis DRS results showed that CuO species were formed in Cu-ZSM-5, while little changes were observed for the Cu-SAPO-34. Cu-SAPO-34 showed high sulfur and hydrocarbon poison resistance compared to Cu-ZSM-5. In summary, Cu-SAPO-34 with small-pore zeolite showed higher hydrothermal stability and better hydrocarbon and sulfur poison resistant than Cu-ZSM-5 with medium-pore.