Background: The common cold is inarguably a multi-symptom syndrome. Thus, patients commonly use several medicinal products simultaneously to treat a range of co-existing clinical manifestations. Topical ointments...Background: The common cold is inarguably a multi-symptom syndrome. Thus, patients commonly use several medicinal products simultaneously to treat a range of co-existing clinical manifestations. Topical ointments with medicated vapours are a popular and effective treatment for the relief of various respiratory tract symptoms. Vicks VapoRub (VVR), a paraffin-based therapeutic ointment containing levomenthol, eucalyptus oil, turpentine oil and camphor, is frequently combined with other cough and cold treatments. However, little is known about which medications are commonly taken together and how patients experience the combined efficacy. Methods: A 20-question online survey to assess habits and beliefs amongst cold sufferers was conducted using the Toluna Start platform. A total of 1513 adults that had suffered from a cold or mild COVID-19 infection in the preceding 12 months were recruited from five European countries. Results: Most cold sufferers combined VVR with other cold medicines, such as paracetamol (75.9%), multi-symptom relief (MSR) products (64.0%) or nasal decongestants (57.0%) to treat their symptoms. VVR was mainly used topically, at night, and on days 3 - 4 of the disease. The addition of VVR to the treatment regimen was perceived as highly effective at relieving multiple cold symptoms. Furthermore, improved sleep and a free breathing sensation were attributed to VVR when used in combination with other cold remedies. Statements on VVR regarding effectiveness, sleep, sleep + effectiveness, speed of action and user satisfaction were agreed upon by a total of 74.8% to 88.3% of panellists. Conclusion: Our survey confirms that in Europe, VVR is commonly used as part of a regimen to manage cold symptoms, and contributes to better overall perceived relief as part of a multi-facetted treatment approach. Prospective clinical data are needed to further confirm these results.展开更多
This up-to-date overview will look at the rationale for the recommendation of combination products for multi-symptom relief of common cold and flu. Common cold and flu are defined by their multi-symptom nature with da...This up-to-date overview will look at the rationale for the recommendation of combination products for multi-symptom relief of common cold and flu. Common cold and flu are defined by their multi-symptom nature with data showing a variety of symptoms reported simultaneously each day over the first six days of illness. Multi-ingredient combination products for multi-symptom relief are formulated to safely, simply, and simultaneously treat multiple symptoms when used as directed. The rationale for the formulation combination products for common cold and flu is therefore practical, logical and reasonable. No evidence has been found that multi-symptom relief medicines are inherently less safe than single-active ingredient medicines. Multi-symptom relief combination products containing several active ingredients provide a safe, effective, cost-effective, and convenient way of treating the multiple symptoms of common cold and flu, when used as directed. This therapy requires some special information for the patient to be provided by the physician and the pharmacist.展开更多
The liquid-cooled battery energy sto rage system(LCBESS) has gained significant attention due to its superior thermal management capacity.However,liquid-cooled battery pack(LCBP) usually has a high sealing level above...The liquid-cooled battery energy sto rage system(LCBESS) has gained significant attention due to its superior thermal management capacity.However,liquid-cooled battery pack(LCBP) usually has a high sealing level above IP65,which can trap flammable and explosive gases from battery thermal runaway and cause explosions.This poses serious safety risks and challenges for LCBESS.In this study,we tested overcharged battery inside a commercial LCBP and found that the conventionally mechanical pressure relief valve(PRV) on the LCBP had a delayed response and low-pressure relief efficiency.A realistic 20-foot model of an energy storage cabin was constructed using the Flacs finite element simulation software.Comparative studies were conducted to evaluate the pressure relief efficiency and the influence on neighboring battery packs in case of internal explosions,considering different sizes and installation positions of the PRV.Here,a newly developed electric-controlled PRV integrated with battery fault detection is introduced,capable of starting within 50 ms of the battery safety valve opening.Furthermore,the PRV was integrated with the battery management system and changed the battery charging and discharging strategy after the PRV was opened.Experimental tests confirmed the efficacy of this method in preventing explosions.This paper addresses the safety concerns associated with LCBPs and proposes an effective solution for explosion relief.展开更多
Bone metastases(BM)are a common complication in advanced cancer patients,significantly contributing to morbidity and mortality due to their ability to cause pain,fractures,and spinal cord compression.Radiation therapy...Bone metastases(BM)are a common complication in advanced cancer patients,significantly contributing to morbidity and mortality due to their ability to cause pain,fractures,and spinal cord compression.Radiation therapy(RT)is vital in managing these complications by targeting metastatic lesions to ease pain,improve mobility,and reduce the risk of skeletal-related events such as fractures.Evidence supports the effectiveness of RT in pain relief,showing its ability to provide significant palliation and lessen the need for opioid painkillers,thereby enhancing the overall quality of life(QoL)for patients with BM.However,optimizing RT outcomes involves considerations such as the choice of radiation technique,dose fractionation schedules,and the integration of supportive care measures to mitigate treatment-related side effects like fatigue and skin reactions.These factors highlight the importance of personalized treatment planning tailored to individual patient needs and tumor characteristics.This mini-review aims to provide comprehensive insights into the multifaceted impacts of RT on pain management and QoL enhancement in BM patients,with implications for refining clinical practices and advancing patient care through the synthesis of findings from various studies.展开更多
Background: Chronic stress is a emotional challenge. Constant pressure presents a serious risk of damage to mental and physical health and hence is associated with increased incidence of various diseases. The ability ...Background: Chronic stress is a emotional challenge. Constant pressure presents a serious risk of damage to mental and physical health and hence is associated with increased incidence of various diseases. The ability to cope with chronic stress may be a function of psychological resilience including intellectual capacities, but more so of external factors such as life experience and education. Adolescents are more vulnerable to chronic stress than adults. The measures introduced during the COVID-19 pandemic brought up major societal problems. As both children and adolescents lost their life anchors, the prevalence of stress in adolescents increased from 20% to 45%. Chronic psychological stress can impede the normal development of schoolchildren. It may cause anxiety, social withdrawal, interpersonal conflicts and aggression. This applies particularly to those in puberty, with the adolescent already facing unstable social bonds and elevated fear about the future. It is likely that the puberty cohort accounts for the dramatic increase in the prevalence of stress. Since it impacts public health, chronic stress among school-age children is increasingly taking on a socio-political dimension. Non-clinical stress intervention studies can investigate how to achieve stress reduction in school children. Methods: In a small pilot study, we analysed the effects of a training program with four different standard interventions, i.e. mindfulness training, progressive muscle reflection, autogenic training, and sound meditation. We obtained baseline scores of 10 stress-indicators, and re-tested after the interventions were performed. Results: The four applied interventions resulted in a reduction of 8 (out of 10) stress-indicators, such as “feeling stressed” or stress related symptoms (headaches, dizziness, sweating). This positive impact of the interventions significantly reduced “Fears about the future” (p Discussion: School children recognise the positive potential of stress reducing training or interventions. Our results provide evidence in support of integrating the training of relaxation techniques in the school curriculum. We propose that a larger study be undertaken to determine which methods would be most effective.展开更多
Background:In today’s society the ongoing discussion about euthanasia triggers emotionally charged debates surrounding the delicate balance between valuing life and respecting an individual’s autonomy.With the persi...Background:In today’s society the ongoing discussion about euthanasia triggers emotionally charged debates surrounding the delicate balance between valuing life and respecting an individual’s autonomy.With the persistence of this debate,there has been the emergence of the concept of the so-called alternative:palliative care.Positioned as a substitute for euthanasia,palliative care aims to alleviate suffering in terminally ill patients without engaging in the ethical dilemmas associated with euthanasia.Methods:This paper explores the facets of palliative care highlighting its core objectives such as providing adequate pain relief as a compassionate alternative to euthanasia.Results:By examining palliative care as a comprehensive approach to end of life support,this study challenges the perceived necessity of euthanasia and advocates,for compassionate and dignified end of life experiences.Conclusion:In conclusion,palliative care emerges as a viable and ethically sound alternative to euthanasia,emphasizing the importance of compassionate end-of-life care and pain management.展开更多
Ceramic relief mural is a contemporary landscape art that is carefully designed based on human nature,culture,and architectural wall space,combined with social customs,visual sensibility,and art.It may also become the...Ceramic relief mural is a contemporary landscape art that is carefully designed based on human nature,culture,and architectural wall space,combined with social customs,visual sensibility,and art.It may also become the main axis of ceramic art in the future.Taiwan public ceramic relief murals(PCRM)are most distinctive with the PCRM pioneered by Pan-Hsiung Chu of Meinong Kiln in 1987.In addition to breaking through the limitations of traditional public ceramic murals,Chu leveraged local culture and sensibility.The theme of art gives PCRM its unique style and innovative value throughout the Taiwan region.This study mainly analyzes and understands the design image of public ceramic murals,taking Taiwan PCRM’s design and creation as the scope,and applies STEEP analysis,that is,the social,technological,economic,ecological,and political-legal environments are analyzed as core factors;eight main important factors in the artistic design image of ceramic murals are evaluated.Then,interpretive structural modeling(ISM)is used to establish five levels,analyze the four main problems in the main core factor area and the four main target results in the affected factor area;and analyze the problem points and target points as well as their causal relationships.It is expected to sort out the relationship between these factors,obtain the hierarchical relationship of each factor,and provide a reference basis and research methods.展开更多
This literature review examines the mechanisms of how exercise, specifically in the form of resistance training, may lead to pain relief in the cancer population. Primary data from three different cancer populations: ...This literature review examines the mechanisms of how exercise, specifically in the form of resistance training, may lead to pain relief in the cancer population. Primary data from three different cancer populations: breast, prostate, and lung, will be examined. A number of experimental studies have been conducted to confirm the effectiveness of resistance training on pain relief as well as the biochemical pathways that relate to this process. In this review, we will examine 5 randomized controlled trials. For the purposes of this review, pain is defined as physical suffering or discomfort associated with illness. Pain is the body’s natural signal, bringing attention to damage that has been sustained by tissues. However, chronic pain is common in the cancer population, and often serves no good purpose but instead will negatively impact both physical and mental health. The three types of pain: nociceptive, neuropathic, and inflammatory pathways have been investigated, and the knowledge of pain mechanisms allows for the understanding of how it is associated with pain. The purpose of this exploratory literature review is to give insight on how to maximize pain-relieving effects of resistance training. Research has indicated that resistance training modulates pain pathways by upregulating the release of pain-relieving substances including beta-endorphins, anti-inflammatory cytokines, and endocannabinoids. Understanding of the benefits of resistance training may be useful in relieving cancer pain, and reproducing effects of pain-relieving strategies while minimizing the symptoms related to cancer and its treatment.展开更多
Current research on pilot-operated relief valve stability is primarily conducted from the perspective of system dynamics or stability criteria,and most of the existing conclusions focus on the spool shape,damping hole...Current research on pilot-operated relief valve stability is primarily conducted from the perspective of system dynamics or stability criteria,and most of the existing conclusions focus on the spool shape,damping hole size,and pulsation frequency of the pump.However,the essential factors pertaining to the unstable vibration of relief valves remain ambiguous.In this study,the dynamic behavior of a pilot-operated relief valve is investigated using the frequency-domain method.The result suggests that the dynamic pressure feedback orifice is vital to the dynamic characteristics of the valve.A large orifice has a low flow resistance.In this case,the fluid in the main spring chamber flows freely,which is not conducive to the stability of the relief valve.However,a small orifice may create significant flow resistance,thus restricting fluid flow.In this case,the oil inside the main valve spring chamber is equivalent to a high-stiffness liquid spring.The main mass-spring vibration system has a natural frequency that differs significantly from the operating frequency of the relief valve,which is conducive to the stability of the relief valve.Good agreement is obtained between the theoretical analysis and experiments.The results indicate that designing a dynamic pressure feedback orifice of an appropriate size is beneficial to improving the stability of hydraulic pilot-operated relief valves.In addition,the dynamic pressure feedback orifice reduces the response speed of the relief valve.This study comprehensively considers the stability,rapidity,and immunity of relief valves and expands current investigations into the dynamic characteristics of relief valves from the perspective of classical control theory,thus revealing the importance of different parameters.展开更多
The Türkiye-Syria earthquake is pushing global search and rescue capacity to the limit On February 6,a powerful earthquake and a series of strong aftershocks struck southern Türkiye near the Syrian border.In...The Türkiye-Syria earthquake is pushing global search and rescue capacity to the limit On February 6,a powerful earthquake and a series of strong aftershocks struck southern Türkiye near the Syrian border.International assistance has since poured into the disaster-hit areas.According to Turkish Foreign Minister Mevlut Cavusoglu,as of February 18,102 countries had offered humanitarian aid and rescue teams from 88 countries participated in search and rescue operations in Türkiye.展开更多
China has cancelled Rwanda’s $7.1-million loan used for building a road Residents in the Masaka and Kabuga suburbs of Rwanda’s capital Kigali were happy to learn that the Chinese government has decided to cancel the...China has cancelled Rwanda’s $7.1-million loan used for building a road Residents in the Masaka and Kabuga suburbs of Rwanda’s capital Kigali were happy to learn that the Chinese government has decided to cancel the debt used for the construction of a road in their locality.展开更多
滑坡易发性评价是滑坡灾害防治的重要手段之一,而不合理的滑坡负样本会影响滑坡易发性评价,从而影响到滑坡灾害的防治,因此提供一种合理的负样本选取方法变得尤为关键。以西藏米林市的古滑坡为例,选择高程、坡度、坡向、坡位、距道路距...滑坡易发性评价是滑坡灾害防治的重要手段之一,而不合理的滑坡负样本会影响滑坡易发性评价,从而影响到滑坡灾害的防治,因此提供一种合理的负样本选取方法变得尤为关键。以西藏米林市的古滑坡为例,选择高程、坡度、坡向、坡位、距道路距离、距断层距离、距水系距离、地形起伏度、地层岩性、土地利用类型10类环境因子,使用Relief算法计算环境因子的贡献值并依据贡献值优化选择环境因子;基于环境因子优化的目标空间外向化采样法(target space exteriorization sampling,简称TSES)选择负样本,作为性能优异的随机森林模型的输入变量;之后结合优化的环境因子和正或负样本预测米林市的滑坡易发性,并用混淆矩阵和ROC曲线评价构建模型的性能。为检验环境因子优化的TSES法的有效性和先进性,采用耦合信息量法和TSES法选择滑坡负样本并构建随机森林模型,与环境因子优化的TSES法构建的随机森林模型进行对比研究。结果表明,环境因子优化的TSES法构建的随机森林模型的评价效果较好,其ACC为93.7%、AUC为0.987,均高于耦合信息量、TSES法构成的模型。环境因子优化的TSES法能够提高模型的精度,解决多因子作为约束条件取样中因子选取的问题,为滑坡易发性评价采集负样本提供了新的思路。展开更多
文摘Background: The common cold is inarguably a multi-symptom syndrome. Thus, patients commonly use several medicinal products simultaneously to treat a range of co-existing clinical manifestations. Topical ointments with medicated vapours are a popular and effective treatment for the relief of various respiratory tract symptoms. Vicks VapoRub (VVR), a paraffin-based therapeutic ointment containing levomenthol, eucalyptus oil, turpentine oil and camphor, is frequently combined with other cough and cold treatments. However, little is known about which medications are commonly taken together and how patients experience the combined efficacy. Methods: A 20-question online survey to assess habits and beliefs amongst cold sufferers was conducted using the Toluna Start platform. A total of 1513 adults that had suffered from a cold or mild COVID-19 infection in the preceding 12 months were recruited from five European countries. Results: Most cold sufferers combined VVR with other cold medicines, such as paracetamol (75.9%), multi-symptom relief (MSR) products (64.0%) or nasal decongestants (57.0%) to treat their symptoms. VVR was mainly used topically, at night, and on days 3 - 4 of the disease. The addition of VVR to the treatment regimen was perceived as highly effective at relieving multiple cold symptoms. Furthermore, improved sleep and a free breathing sensation were attributed to VVR when used in combination with other cold remedies. Statements on VVR regarding effectiveness, sleep, sleep + effectiveness, speed of action and user satisfaction were agreed upon by a total of 74.8% to 88.3% of panellists. Conclusion: Our survey confirms that in Europe, VVR is commonly used as part of a regimen to manage cold symptoms, and contributes to better overall perceived relief as part of a multi-facetted treatment approach. Prospective clinical data are needed to further confirm these results.
基金Financial support for this review was provided by P&G and PGT Healthcare.
文摘This up-to-date overview will look at the rationale for the recommendation of combination products for multi-symptom relief of common cold and flu. Common cold and flu are defined by their multi-symptom nature with data showing a variety of symptoms reported simultaneously each day over the first six days of illness. Multi-ingredient combination products for multi-symptom relief are formulated to safely, simply, and simultaneously treat multiple symptoms when used as directed. The rationale for the formulation combination products for common cold and flu is therefore practical, logical and reasonable. No evidence has been found that multi-symptom relief medicines are inherently less safe than single-active ingredient medicines. Multi-symptom relief combination products containing several active ingredients provide a safe, effective, cost-effective, and convenient way of treating the multiple symptoms of common cold and flu, when used as directed. This therapy requires some special information for the patient to be provided by the physician and the pharmacist.
基金sponsored by the Science and Technology Program of State Grid Corporation of China(4000-202355090A-1-1ZN)。
文摘The liquid-cooled battery energy sto rage system(LCBESS) has gained significant attention due to its superior thermal management capacity.However,liquid-cooled battery pack(LCBP) usually has a high sealing level above IP65,which can trap flammable and explosive gases from battery thermal runaway and cause explosions.This poses serious safety risks and challenges for LCBESS.In this study,we tested overcharged battery inside a commercial LCBP and found that the conventionally mechanical pressure relief valve(PRV) on the LCBP had a delayed response and low-pressure relief efficiency.A realistic 20-foot model of an energy storage cabin was constructed using the Flacs finite element simulation software.Comparative studies were conducted to evaluate the pressure relief efficiency and the influence on neighboring battery packs in case of internal explosions,considering different sizes and installation positions of the PRV.Here,a newly developed electric-controlled PRV integrated with battery fault detection is introduced,capable of starting within 50 ms of the battery safety valve opening.Furthermore,the PRV was integrated with the battery management system and changed the battery charging and discharging strategy after the PRV was opened.Experimental tests confirmed the efficacy of this method in preventing explosions.This paper addresses the safety concerns associated with LCBPs and proposes an effective solution for explosion relief.
文摘Bone metastases(BM)are a common complication in advanced cancer patients,significantly contributing to morbidity and mortality due to their ability to cause pain,fractures,and spinal cord compression.Radiation therapy(RT)is vital in managing these complications by targeting metastatic lesions to ease pain,improve mobility,and reduce the risk of skeletal-related events such as fractures.Evidence supports the effectiveness of RT in pain relief,showing its ability to provide significant palliation and lessen the need for opioid painkillers,thereby enhancing the overall quality of life(QoL)for patients with BM.However,optimizing RT outcomes involves considerations such as the choice of radiation technique,dose fractionation schedules,and the integration of supportive care measures to mitigate treatment-related side effects like fatigue and skin reactions.These factors highlight the importance of personalized treatment planning tailored to individual patient needs and tumor characteristics.This mini-review aims to provide comprehensive insights into the multifaceted impacts of RT on pain management and QoL enhancement in BM patients,with implications for refining clinical practices and advancing patient care through the synthesis of findings from various studies.
文摘Background: Chronic stress is a emotional challenge. Constant pressure presents a serious risk of damage to mental and physical health and hence is associated with increased incidence of various diseases. The ability to cope with chronic stress may be a function of psychological resilience including intellectual capacities, but more so of external factors such as life experience and education. Adolescents are more vulnerable to chronic stress than adults. The measures introduced during the COVID-19 pandemic brought up major societal problems. As both children and adolescents lost their life anchors, the prevalence of stress in adolescents increased from 20% to 45%. Chronic psychological stress can impede the normal development of schoolchildren. It may cause anxiety, social withdrawal, interpersonal conflicts and aggression. This applies particularly to those in puberty, with the adolescent already facing unstable social bonds and elevated fear about the future. It is likely that the puberty cohort accounts for the dramatic increase in the prevalence of stress. Since it impacts public health, chronic stress among school-age children is increasingly taking on a socio-political dimension. Non-clinical stress intervention studies can investigate how to achieve stress reduction in school children. Methods: In a small pilot study, we analysed the effects of a training program with four different standard interventions, i.e. mindfulness training, progressive muscle reflection, autogenic training, and sound meditation. We obtained baseline scores of 10 stress-indicators, and re-tested after the interventions were performed. Results: The four applied interventions resulted in a reduction of 8 (out of 10) stress-indicators, such as “feeling stressed” or stress related symptoms (headaches, dizziness, sweating). This positive impact of the interventions significantly reduced “Fears about the future” (p Discussion: School children recognise the positive potential of stress reducing training or interventions. Our results provide evidence in support of integrating the training of relaxation techniques in the school curriculum. We propose that a larger study be undertaken to determine which methods would be most effective.
文摘Background:In today’s society the ongoing discussion about euthanasia triggers emotionally charged debates surrounding the delicate balance between valuing life and respecting an individual’s autonomy.With the persistence of this debate,there has been the emergence of the concept of the so-called alternative:palliative care.Positioned as a substitute for euthanasia,palliative care aims to alleviate suffering in terminally ill patients without engaging in the ethical dilemmas associated with euthanasia.Methods:This paper explores the facets of palliative care highlighting its core objectives such as providing adequate pain relief as a compassionate alternative to euthanasia.Results:By examining palliative care as a comprehensive approach to end of life support,this study challenges the perceived necessity of euthanasia and advocates,for compassionate and dignified end of life experiences.Conclusion:In conclusion,palliative care emerges as a viable and ethically sound alternative to euthanasia,emphasizing the importance of compassionate end-of-life care and pain management.
文摘Ceramic relief mural is a contemporary landscape art that is carefully designed based on human nature,culture,and architectural wall space,combined with social customs,visual sensibility,and art.It may also become the main axis of ceramic art in the future.Taiwan public ceramic relief murals(PCRM)are most distinctive with the PCRM pioneered by Pan-Hsiung Chu of Meinong Kiln in 1987.In addition to breaking through the limitations of traditional public ceramic murals,Chu leveraged local culture and sensibility.The theme of art gives PCRM its unique style and innovative value throughout the Taiwan region.This study mainly analyzes and understands the design image of public ceramic murals,taking Taiwan PCRM’s design and creation as the scope,and applies STEEP analysis,that is,the social,technological,economic,ecological,and political-legal environments are analyzed as core factors;eight main important factors in the artistic design image of ceramic murals are evaluated.Then,interpretive structural modeling(ISM)is used to establish five levels,analyze the four main problems in the main core factor area and the four main target results in the affected factor area;and analyze the problem points and target points as well as their causal relationships.It is expected to sort out the relationship between these factors,obtain the hierarchical relationship of each factor,and provide a reference basis and research methods.
文摘This literature review examines the mechanisms of how exercise, specifically in the form of resistance training, may lead to pain relief in the cancer population. Primary data from three different cancer populations: breast, prostate, and lung, will be examined. A number of experimental studies have been conducted to confirm the effectiveness of resistance training on pain relief as well as the biochemical pathways that relate to this process. In this review, we will examine 5 randomized controlled trials. For the purposes of this review, pain is defined as physical suffering or discomfort associated with illness. Pain is the body’s natural signal, bringing attention to damage that has been sustained by tissues. However, chronic pain is common in the cancer population, and often serves no good purpose but instead will negatively impact both physical and mental health. The three types of pain: nociceptive, neuropathic, and inflammatory pathways have been investigated, and the knowledge of pain mechanisms allows for the understanding of how it is associated with pain. The purpose of this exploratory literature review is to give insight on how to maximize pain-relieving effects of resistance training. Research has indicated that resistance training modulates pain pathways by upregulating the release of pain-relieving substances including beta-endorphins, anti-inflammatory cytokines, and endocannabinoids. Understanding of the benefits of resistance training may be useful in relieving cancer pain, and reproducing effects of pain-relieving strategies while minimizing the symptoms related to cancer and its treatment.
基金Supported by National Natural Science Foundation of China(Grant No.52175059)National Key Research and Development Program of China(Grant No.2018YFB2001100).
文摘Current research on pilot-operated relief valve stability is primarily conducted from the perspective of system dynamics or stability criteria,and most of the existing conclusions focus on the spool shape,damping hole size,and pulsation frequency of the pump.However,the essential factors pertaining to the unstable vibration of relief valves remain ambiguous.In this study,the dynamic behavior of a pilot-operated relief valve is investigated using the frequency-domain method.The result suggests that the dynamic pressure feedback orifice is vital to the dynamic characteristics of the valve.A large orifice has a low flow resistance.In this case,the fluid in the main spring chamber flows freely,which is not conducive to the stability of the relief valve.However,a small orifice may create significant flow resistance,thus restricting fluid flow.In this case,the oil inside the main valve spring chamber is equivalent to a high-stiffness liquid spring.The main mass-spring vibration system has a natural frequency that differs significantly from the operating frequency of the relief valve,which is conducive to the stability of the relief valve.Good agreement is obtained between the theoretical analysis and experiments.The results indicate that designing a dynamic pressure feedback orifice of an appropriate size is beneficial to improving the stability of hydraulic pilot-operated relief valves.In addition,the dynamic pressure feedback orifice reduces the response speed of the relief valve.This study comprehensively considers the stability,rapidity,and immunity of relief valves and expands current investigations into the dynamic characteristics of relief valves from the perspective of classical control theory,thus revealing the importance of different parameters.
文摘The Türkiye-Syria earthquake is pushing global search and rescue capacity to the limit On February 6,a powerful earthquake and a series of strong aftershocks struck southern Türkiye near the Syrian border.International assistance has since poured into the disaster-hit areas.According to Turkish Foreign Minister Mevlut Cavusoglu,as of February 18,102 countries had offered humanitarian aid and rescue teams from 88 countries participated in search and rescue operations in Türkiye.
文摘China has cancelled Rwanda’s $7.1-million loan used for building a road Residents in the Masaka and Kabuga suburbs of Rwanda’s capital Kigali were happy to learn that the Chinese government has decided to cancel the debt used for the construction of a road in their locality.
文摘滑坡易发性评价是滑坡灾害防治的重要手段之一,而不合理的滑坡负样本会影响滑坡易发性评价,从而影响到滑坡灾害的防治,因此提供一种合理的负样本选取方法变得尤为关键。以西藏米林市的古滑坡为例,选择高程、坡度、坡向、坡位、距道路距离、距断层距离、距水系距离、地形起伏度、地层岩性、土地利用类型10类环境因子,使用Relief算法计算环境因子的贡献值并依据贡献值优化选择环境因子;基于环境因子优化的目标空间外向化采样法(target space exteriorization sampling,简称TSES)选择负样本,作为性能优异的随机森林模型的输入变量;之后结合优化的环境因子和正或负样本预测米林市的滑坡易发性,并用混淆矩阵和ROC曲线评价构建模型的性能。为检验环境因子优化的TSES法的有效性和先进性,采用耦合信息量法和TSES法选择滑坡负样本并构建随机森林模型,与环境因子优化的TSES法构建的随机森林模型进行对比研究。结果表明,环境因子优化的TSES法构建的随机森林模型的评价效果较好,其ACC为93.7%、AUC为0.987,均高于耦合信息量、TSES法构成的模型。环境因子优化的TSES法能够提高模型的精度,解决多因子作为约束条件取样中因子选取的问题,为滑坡易发性评价采集负样本提供了新的思路。