Creation of arbitrary features with high resolution is critically important in the fabrication of nano-optoelectronic devices.Here,sub-50 nm surface structuring is achieved directly on Sb2S3 thin films via microsphere...Creation of arbitrary features with high resolution is critically important in the fabrication of nano-optoelectronic devices.Here,sub-50 nm surface structuring is achieved directly on Sb2S3 thin films via microsphere femtosecond laser irradi-ation in far field.By varying laser fluence and scanning speed,nano-feature sizes can be flexibly tuned.Such small patterns are attributed to the co-effect of microsphere focusing,two-photons absorption,top threshold effect,and high-repetition-rate femtosecond laser-induced incubation effect.The minimum feature size can be reduced down to~30 nm(λ/26)by manipulating film thickness.The fitting analysis between the ablation width and depth predicts that the feature size can be down to~15 nm at the film thickness of~10 nm.A nano-grating is fabricated,which demonstrates desirable beam diffraction performance.This nano-scale resolution would be highly attractive for next-generation laser nano-lithography in far field and in ambient air.展开更多
In this paper,we establish the unique determination result for inverse acoustic scattering of a penetrable obstacle with a general conductive boundary condition by using phaseless far field data at a fixed frequency.I...In this paper,we establish the unique determination result for inverse acoustic scattering of a penetrable obstacle with a general conductive boundary condition by using phaseless far field data at a fixed frequency.It is well-known that the modulus of the far field pattern is invariant under translations of the scattering obstacle if only one plane wave is used as the incident field,so it is impossible to reconstruct the location of the underlying scatterers.Based on some new research results on the impenetrable obstacle and inhomogeneous isotropic medium,we consider different types of superpositions of incident waves to break the translation invariance property.展开更多
Context/objectives: The COVID-19 pandemic has disrupted all programs, potentially impacting access to health services for children under 5 years old. The Far North of Cameroon is one of the northern regions with a pre...Context/objectives: The COVID-19 pandemic has disrupted all programs, potentially impacting access to health services for children under 5 years old. The Far North of Cameroon is one of the northern regions with a prevalence of malnourished children ranging from 5% to 10%. Due to the barrier measures implemented to combat the pandemic, many parents are reluctant to take their children to healthcare facilities. Some of these children were benefiting from the Ambulatory Care Center (ACC) program prior to the COVID-19 outbreak. The main objective of this research is to assess the impact of COVID-19 on access to health services for children under 5 in the Mayo Tsanaga (MT) and Logone & Chari (LC) departments. The implementation of barrier measures could significantly increase the risk of malnutrition among children under 5 years old. Method: A cross-sectional analytical study was conducted in the MT and LC departments, employing both retrospective and prospective approaches. Data was collected through questionnaire, interview guide and a review of existing data prior to the pandemic (DHIS 2). Kobo Collect software was used for data collection, and R software was used for analysis. Results: Children who benefitted from the ACC program during the COVID-19 period were found to have a lower prevalence of malnutrition compared to those who did not benefit (OR: 0.09, CI {0.0 - 0.44}). Conclusion: COVID-19 has led to a decrease in the utilization of health facilities in both departments of the study, resulting in an increase in health issues such as malnutrition among children under 5 years old. Various policies have been implemented to improve attendance at health facilities.展开更多
Far infrared(FIR)radiation(3-100µm)is an electromagnetic spectrum commonly studied for biological effects.This article aims to discuss using Far infrared radiation with sub-division(4-24µm)of this waveband t...Far infrared(FIR)radiation(3-100µm)is an electromagnetic spectrum commonly studied for biological effects.This article aims to discuss using Far infrared radiation with sub-division(4-24µm)of this waveband to stimulate tissues and cells and is considered an effective therapeutic modality for specific medical disorders.The IR application as a medical therapy has advanced rapidly in recent years.For example,IR therapy like IR-emitting apparel and materials that can be run solely by body heat(does not need an external power supply)have been developed.New methods for providing FIR radiation to the human body have emerged due to technological advancements.Specialty saunas and lamps that emit pure FIR radiation have become effective,safe,and widely used therapeutic sources.Fibers infused with thermide,FIR emitting ceramic nanomaterials and knitted into fabrics are used as clothes and apparel to produce FIR radiation and benefit from its effects.A deeper understanding of FIR's significant innovations and biological implications could aid in improving therapeutic efficacy or developing new methods that use FIR wavelengths.展开更多
基金This work is supported by Academic Research Fund Tier 2,Ministry of Education-Singapore(MOE2019-T2-2-147)T.C.acknowledges support from the National Key Research and Development Program of China(2019YFA0709100,2020YFA0714504).
文摘Creation of arbitrary features with high resolution is critically important in the fabrication of nano-optoelectronic devices.Here,sub-50 nm surface structuring is achieved directly on Sb2S3 thin films via microsphere femtosecond laser irradi-ation in far field.By varying laser fluence and scanning speed,nano-feature sizes can be flexibly tuned.Such small patterns are attributed to the co-effect of microsphere focusing,two-photons absorption,top threshold effect,and high-repetition-rate femtosecond laser-induced incubation effect.The minimum feature size can be reduced down to~30 nm(λ/26)by manipulating film thickness.The fitting analysis between the ablation width and depth predicts that the feature size can be down to~15 nm at the film thickness of~10 nm.A nano-grating is fabricated,which demonstrates desirable beam diffraction performance.This nano-scale resolution would be highly attractive for next-generation laser nano-lithography in far field and in ambient air.
文摘In this paper,we establish the unique determination result for inverse acoustic scattering of a penetrable obstacle with a general conductive boundary condition by using phaseless far field data at a fixed frequency.It is well-known that the modulus of the far field pattern is invariant under translations of the scattering obstacle if only one plane wave is used as the incident field,so it is impossible to reconstruct the location of the underlying scatterers.Based on some new research results on the impenetrable obstacle and inhomogeneous isotropic medium,we consider different types of superpositions of incident waves to break the translation invariance property.
文摘Context/objectives: The COVID-19 pandemic has disrupted all programs, potentially impacting access to health services for children under 5 years old. The Far North of Cameroon is one of the northern regions with a prevalence of malnourished children ranging from 5% to 10%. Due to the barrier measures implemented to combat the pandemic, many parents are reluctant to take their children to healthcare facilities. Some of these children were benefiting from the Ambulatory Care Center (ACC) program prior to the COVID-19 outbreak. The main objective of this research is to assess the impact of COVID-19 on access to health services for children under 5 in the Mayo Tsanaga (MT) and Logone & Chari (LC) departments. The implementation of barrier measures could significantly increase the risk of malnutrition among children under 5 years old. Method: A cross-sectional analytical study was conducted in the MT and LC departments, employing both retrospective and prospective approaches. Data was collected through questionnaire, interview guide and a review of existing data prior to the pandemic (DHIS 2). Kobo Collect software was used for data collection, and R software was used for analysis. Results: Children who benefitted from the ACC program during the COVID-19 period were found to have a lower prevalence of malnutrition compared to those who did not benefit (OR: 0.09, CI {0.0 - 0.44}). Conclusion: COVID-19 has led to a decrease in the utilization of health facilities in both departments of the study, resulting in an increase in health issues such as malnutrition among children under 5 years old. Various policies have been implemented to improve attendance at health facilities.
文摘Far infrared(FIR)radiation(3-100µm)is an electromagnetic spectrum commonly studied for biological effects.This article aims to discuss using Far infrared radiation with sub-division(4-24µm)of this waveband to stimulate tissues and cells and is considered an effective therapeutic modality for specific medical disorders.The IR application as a medical therapy has advanced rapidly in recent years.For example,IR therapy like IR-emitting apparel and materials that can be run solely by body heat(does not need an external power supply)have been developed.New methods for providing FIR radiation to the human body have emerged due to technological advancements.Specialty saunas and lamps that emit pure FIR radiation have become effective,safe,and widely used therapeutic sources.Fibers infused with thermide,FIR emitting ceramic nanomaterials and knitted into fabrics are used as clothes and apparel to produce FIR radiation and benefit from its effects.A deeper understanding of FIR's significant innovations and biological implications could aid in improving therapeutic efficacy or developing new methods that use FIR wavelengths.
