Two cylindrical vessels under internal pressure are used for this work in order to study the influence of the position and size of defects on their elastic and elastoplastic behavior. One contains two external longitu...Two cylindrical vessels under internal pressure are used for this work in order to study the influence of the position and size of defects on their elastic and elastoplastic behavior. One contains two external longitudinal semi-elliptic defects of different dimensions realized diametrically opposed. The other contains the same defects but is circumferential. These defects are carried out by elect-erosion. Strain gauges are placed in the neighborhood of the defects of which the purpose is to obtain the strain distribution. This work also allows the comparison between two defects of different dimensions, which are of the same shape or different shapes. These defects are longitudinal and circumferential semi-elliptical. The position of these defects relative to the inner radius of a cylindrical pressure vessel is considered. The deformations results are discussed.展开更多
In order to investigate the effect of die wall thickness on morphologies of defect band,a stepped mold with a wall thickness of 5 mm,4 mm,3 mm,2 mm,and 1 mm was designed to carry out high pressure die casting experime...In order to investigate the effect of die wall thickness on morphologies of defect band,a stepped mold with a wall thickness of 5 mm,4 mm,3 mm,2 mm,and 1 mm was designed to carry out high pressure die casting experiments with AlSi10 MgMn alloy.For castings with wall thickness of 2-4 mm,the ratio of the mean defect band width(w)and mean grain size(d)in the defect band(w/d)ranges 7-18,while it increases to 24.47 for the 5 mm-thick casting.This difference is related with the filling speed and the distribution of externally solidified crystals(ESCs).The mold flow analysis indicates that the filling speed decreases from 25.41 m·s^(-1)to 11.07 m·s^(-1)when wall thickness increases from 2 mm to 5 mm.Due to the decreasing filling speed along the wall thickness,ESCs gradually diffuse from the center to the defect band,which keep the shear strength in the defect band at a high-level during filling.Meanwhile,the shear strength generated during the filling also decreases as the shear rate drops.Finally,the defect bands in the 5 mm-thick region become widen and indistinct,and the porosity is as high as 5.25%.展开更多
Recently,the newly synthesized septuple-atomic layer two-dimensional(2D)material MoSi_(2)N_(4)(MSN)has attracted attention worldwide.Our work delves into the effect of vacancies and external electric fields on the ele...Recently,the newly synthesized septuple-atomic layer two-dimensional(2D)material MoSi_(2)N_(4)(MSN)has attracted attention worldwide.Our work delves into the effect of vacancies and external electric fields on the electronic properties of the MSN/graphene(Gr)heterostructure using first-principles calculation.We find that four types of defective structures,N-in,N-out,Si and Mo vacancy defects of monolayer MSN and MSN/Gr heterostructure are stable in air.Moreover,vacancy defects can effectively modulate the charge transfer at the interface of the MSN/Gr heterostructure as well as the work function of the pristine monolayer MSN and MSN/Gr heterostructure.Finally,the application of an external electric field enables the dynamic switching between n-type and p-type Schottky contacts.Our work may offer the possibility of exceeding the capabilities of conventional Schottky diodes based on MSN/Gr heterostructures.展开更多
Objective To provide evidence for more accurate diagnosis of birth defects based on the pathoauatomy of congenital malformations. Methods Data used in this study were obtained fi＇om Luliang City Hospital and three co...Objective To provide evidence for more accurate diagnosis of birth defects based on the pathoauatomy of congenital malformations. Methods Data used in this study were obtained fi＇om Luliang City Hospital and three county hospitals of Shanxi province between February 2004 and March 2006. Autopsy and pathological examination of 160 dead fetuses and stillbirths were performed. Photos of dead fetuses and stillbirths were taken, tissues were cut into sections for pathological examination under microscope, all pathological information was recorded, and percentage of birth defects was calculated. Results The proportion of dead fetuses and stillbirths with or without congenital malformations was 84.4% （135/160） and 15.6% （25/160）, respectively. There were 16 categories of major external and internal birth defects in 135 cases of such defects. Congenital heart defects, anencephaly and spina bifida had a higher prevalence rate in the study period. The prevalence rate of non-malformation death and birth defects 〈 28 gestational weeks and internal anomalies ≥ 28 gestational weeks was 14.61% （61/4175） and 17.25% （72/4175）, respectively. A total of 413 in situ anomalies were found in 135 cases of autopsy. Spina bifida, anencephaly, congenital heart defects, aplasia or accessory lobe of lung, renal agenesis and dysplasis and congenital hydrocephaly were more closely associated with severe malformations than with mitis malformations. The cases of dead fetuses and stillbirths with multiple malformations （/〉 2 in situ anomalies） had a higher proportion （74.1%）, whereas those with isolated malformations had a lower proportion （25.93%）. Conclusion The occurrence of congenital malformations in different embryonic developmental stages affects multiple organs. Postmortem examination of internal and multiple malformations of fetal deaths and stillbirths can provide more accurate diagnostic information for birth defects.展开更多
Management of post-traumatic long-bone defects remains relevant and cha-llenging despite the rapid development of approaches to their treatment.Do-minant positions are occupied by the Ilizarov method,bone autogenous g...Management of post-traumatic long-bone defects remains relevant and cha-llenging despite the rapid development of approaches to their treatment.Do-minant positions are occupied by the Ilizarov method,bone autogenous grafting and the Masquelet induced membrane technique(IMT).The IMT is aimed at reducing extensive defect treatment duration and for this reason has gained great popularity.However,the assessment of its effectiveness is difficult due to a limited number of clinical series.The varying clinical manifestations of bone defect severity do not allow a comprehensive evaluation of IMT effectiveness.One of them is infection in the defect area.The purpose of our literature review is an analysis of studies on IMT application in infected vs non-infected long-bone defects of the lower extremities published over the last 10 years.It focuses on the investigation of similarities and fundamental differences in the need for antibiotics,timing of spacer fixation,methods of collecting donor bone and fixators used for consolidation.The studies show that the IMT has been globally used in aseptic and osteomyelitic defects due to its clinical effectiveness.Authors’variations and improvements in its practical implementation indicate the ongoing development and the interest of researchers in this technique.展开更多
The performance degradation of micro light-emitting diodes(micro-LEDs)is closely associated with the deterioration of sidewall passivation layers under prolonged electrical bias.We investigate reliability improvements...The performance degradation of micro light-emitting diodes(micro-LEDs)is closely associated with the deterioration of sidewall passivation layers under prolonged electrical bias.We investigate reliability improvements in 20μm×20μm InGaN/GaN blue micro-LEDs by suppressing the formation of an unstable interfacial layer during sidewall passivation.SiO_(2)is deposited on the etched mesa sidewalls using either Sputtering or plasma-enhanced chemical vapor deposition(PECVD).Comparative analysis reveals that PECVD-passivated devices experience more severe performance degradation,primarily due to the increased leakage current.After 100 h of accelerated aging,external quantum efficiency decreases by 44%in PECVD-passivated samples,whereas Sputter-passivated devices exhibit only an11%reduction.This discrepancy is attributed to the formation of a thicker and chemically unstable gallium oxynitride(Ga-O_(X)-N_(1-X))interfacial layer at the SiO_(2)∕GaN-based interface,which facilitates the generation of sidewall defects.Suppressing the formation of this interlayer enhances the crystallinity and structural stability of the passivation layer,thereby mitigating the activation of point defects.Notably,Sputter deposition is more effective in minimizing the formation of Ga-O-N interlayer.These findings emphasize the critical role of achieving low-defect-density sidewall passivation to improve the reliability of micro-LEDs for next-generation high-resolution display applications.展开更多
Background:Currently,various external tissue expansion devices are becoming widely used.Considering the scarcity of relevant application standards,this systematic review was performed to explore the effectiveness and ...Background:Currently,various external tissue expansion devices are becoming widely used.Considering the scarcity of relevant application standards,this systematic review was performed to explore the effectiveness and safety of external tissue expansion techniques for the reconstruction of soft tissue defects.Method:A systematic review and meta-analysis on the efficacy and safety of external tissue expansion technique was conducted.A comprehensive search was performed in the following electronic databases:PubMed/Medline,Embase,Cochrane Library(Wiley Online Library),andWeb of Science.Studies reporting patients with soft tissue defects under the treatment of external tissue expansion technique were included.Results:A total of 66 studies with 22 different types of external tissue expansion devices met the inclusion criteria.We performed a descriptive analysis of different kinds of devices.A single-arm meta-analysis was performed to evaluate the efficacy and safety of the external tissue expansion technique for different aetiologies.The pooled mean wound healing time among patients with defects after fasciotomy was 10.548 days[95%confidence interval(CI)=5.796-15.299].The pooled median wound healing times of patients with defects after excisional surgery,trauma,chronic ulcers and abdominal defects were 11.218 days(95%CI=6.183-16.253),11.561 days(95%CI=7.062-16.060),15.956 days(95%CI=11.916-19.996)and 12.853 days(95%CI=9.444-16.227),respectively.The pooled wound healing rates of patients with defects after fasciotomy,excisional surgery,trauma,chronic ulcers and abdominal defects were 93.8%(95%CI=87.1-98.2%),97.2%(95%CI=92.2-99.7%),97.0%(95%CI=91.2-99.8%),99.5%(95%CI=97.6-100%),and 96.8%(95%CI=79.2-100%),respectively.We performed a subgroup analysis in patients with diabetic ulcers and open abdominal wounds.The pooled median wound healing time of patients with diabetic ulcers was 11.730 days(95%CI=10.334-13.125).The pooled median wound healing time of patients with open abdomen defects was 48.810 days(95%CI=35.557-62.063)and the pooled successful healing rate was 68.8%(95%CI=45.9-88.1%).A total of 1686 patients were included,265(15.7%)of whom experienced complications.The most common complication was dehiscence(n=53,3.14%).Conclusions:Our systematic review is the first to demonstrate the efficacy and safety of external tissue expansion in the management of soft tissue defects.However,we must interpret the meta-analysis results with caution considering the limitations of this review.Large-scale randomized controlled trials and long-term follow-up studies are still needed to confirm the effectiveness and evaluate the quality of healing.展开更多
Non-invasive potato defects detection has been demanded for sorting and grading purpose.Researches on the classification of the defects has been available,however,investigation on the severity level calculation is lim...Non-invasive potato defects detection has been demanded for sorting and grading purpose.Researches on the classification of the defects has been available,however,investigation on the severity level calculation is limited.For the detection of the common scab,it has been found that imaging in the infrared region provide an interesting characteristic that could distinguish defected area to normal area.Thus,investigations on this wavelength range is interesting to add more knowledge and for applications.In this research,the multispectral image has been obtained and investigated especially at three wavelengths(950,1150,1600 nm).Image pre-processing and pseudo-color conversion techniques were explored to enhance the contrast between defects,normal background skin area and soil deposits.Results show that external defects,such as common scab and some mechanical damage types,appear brighter in the near infrared region,especially at 1600 nm against the normal skin background.It has been found that pseudo-color images conversion provides more information regarding type if surface characteristics compared to grayscale single imaging.Image segmentation using pseudo-color images after multiplication operation pre-processing could be used for common scab and mechanical damage detection excluding soil deposits with a Dice Sorensen coefficient of 0.64.In addition,image segmentation using single image at 1600 nm shown relatively better results with Dice Sorensen coefficient of 0.72 with note that thick soil deposits will also be segmented.Defect severity level evaluation had an R2 correlation of 0.84 against standard measurements of severity.展开更多
The physicochemical properties of surfaces have a great effect on the micro-morphologies of the crystal structures which are in contact with them.Understanding the interaction mechanism between the internal driving fo...The physicochemical properties of surfaces have a great effect on the micro-morphologies of the crystal structures which are in contact with them.Understanding the interaction mechanism between the internal driving forces of the crystal and external inducing forces of the surfaces is the prerequisite of controlling and obtaining the desirable morphologies.In this work,the dynamic density functional theory was applied to construct the free energy functional expression of polyethylene(PE)lattice,and the micro-dynamic evolution processes of PE lattice morphology near the surfaces with different properties were observed to reveal the interaction mechanism at atomic scale.The results showed that the physical and chemical properties of the external surfaces synergistically affect the morphologies in both the defect shapes and the distribution of the defect regions.In the absence of the contact surfaces,driven by the oriented interactions among different CH2 groups,PE lattices gradually grow and form a defect-free structure.Conversely,the presence of contact surfaces leads to lattice defects in the interfacial regions,and PE lattice shows different self-healing abilities around different surfaces.展开更多
Objective: To explore the effect of external fixator and reconstituted bone xenograft (RBX) in the treatment of tibial bone defect, tibial bone nonunion and congenital pseudarthrosis of the tibia with limb shortening....Objective: To explore the effect of external fixator and reconstituted bone xenograft (RBX) in the treatment of tibial bone defect, tibial bone nonunion and congenital pseudarthrosis of the tibia with limb shortening. Methods: Twenty patients ( 13 males and 7 females) with tibial bone defect, tibial bone nonunion or congenital pseudarthrosis of the tibia with limb shortening were treated with external fixation. Two kinds of external fixators were used: a half ring sulcated external fixator used in 13 patients and a combined external fixator in 7 patients. Foot-drop was corrected at the same time with external fixation in 4 patients. The shortened length of the tibia was in the range of 2-9 cm, with an average of 4.8 cm. For bone grafting, RBX was used in 12 patients, autogenous ilium was used in 3 patients and autogenous fibula was implanted as a bone plug into the medullary canal in 1 case, and no bone graft was used in 4 patients. Results: All the 20 patients were followed-up for 8 months to 7 years, averaging 51 months. Satisfactory function of the affected extremities was obtained. All the shortened extremities were lengthened to the expected length. For all the lengthening area and the fracture sites, bone union was obtained at the last. The average healing time of 12 patients treated with RBX was 4.8 months. Conclusions: Both the half ring sulcated external fixator and the combined external fixator have the advantages of small trauma, simple operation, elastic fixation without stress shielding and non-limitation from local soft tissue conditions, and there is satisfactory functional recovery of affected extremities in the treatment of tibial bone defects, tibial bone nonunion and congenital pseudarthrosis of the tibia combined with limb shortening. RBX has good biocompatibility and does not cause immunological rejections. It can also be safely used in treatment of bone nonunion and has reliable effect to promote bone healing.展开更多
文摘Two cylindrical vessels under internal pressure are used for this work in order to study the influence of the position and size of defects on their elastic and elastoplastic behavior. One contains two external longitudinal semi-elliptic defects of different dimensions realized diametrically opposed. The other contains the same defects but is circumferential. These defects are carried out by elect-erosion. Strain gauges are placed in the neighborhood of the defects of which the purpose is to obtain the strain distribution. This work also allows the comparison between two defects of different dimensions, which are of the same shape or different shapes. These defects are longitudinal and circumferential semi-elliptical. The position of these defects relative to the inner radius of a cylindrical pressure vessel is considered. The deformations results are discussed.
基金supported by the National Natural Science Foundation of China(No.52474396 and 52175284)the National Key Research and Development Program of China(Grant No.2022YFB3404201)。
文摘In order to investigate the effect of die wall thickness on morphologies of defect band,a stepped mold with a wall thickness of 5 mm,4 mm,3 mm,2 mm,and 1 mm was designed to carry out high pressure die casting experiments with AlSi10 MgMn alloy.For castings with wall thickness of 2-4 mm,the ratio of the mean defect band width(w)and mean grain size(d)in the defect band(w/d)ranges 7-18,while it increases to 24.47 for the 5 mm-thick casting.This difference is related with the filling speed and the distribution of externally solidified crystals(ESCs).The mold flow analysis indicates that the filling speed decreases from 25.41 m·s^(-1)to 11.07 m·s^(-1)when wall thickness increases from 2 mm to 5 mm.Due to the decreasing filling speed along the wall thickness,ESCs gradually diffuse from the center to the defect band,which keep the shear strength in the defect band at a high-level during filling.Meanwhile,the shear strength generated during the filling also decreases as the shear rate drops.Finally,the defect bands in the 5 mm-thick region become widen and indistinct,and the porosity is as high as 5.25%.
基金Project supported by the Industry and Education Combination Innovation Platform of Intelligent Manufacturing and Graduate Joint Training Base at Guizhou University(Grant No.2020-520000-83-01-324061)the National Natural Science Foundation of China(Grant No.61264004)the High-level Creative Talent Training Program in Guizhou Province of China(Grant No.[2015]4015).
文摘Recently,the newly synthesized septuple-atomic layer two-dimensional(2D)material MoSi_(2)N_(4)(MSN)has attracted attention worldwide.Our work delves into the effect of vacancies and external electric fields on the electronic properties of the MSN/graphene(Gr)heterostructure using first-principles calculation.We find that four types of defective structures,N-in,N-out,Si and Mo vacancy defects of monolayer MSN and MSN/Gr heterostructure are stable in air.Moreover,vacancy defects can effectively modulate the charge transfer at the interface of the MSN/Gr heterostructure as well as the work function of the pristine monolayer MSN and MSN/Gr heterostructure.Finally,the application of an external electric field enables the dynamic switching between n-type and p-type Schottky contacts.Our work may offer the possibility of exceeding the capabilities of conventional Schottky diodes based on MSN/Gr heterostructures.
基金funded by National"973"project on Population and Health(No.2007CB511901)China Postdoctoral Science Fundation Funded Project(No.200801016)+2 种基金National Health Baby Promotion Program(No.FP2000NO13)Education Ministry Key Program(No.02185)National Yang Zi Scholar Program,211 and 985 projects of Peking University(No.20020903)
文摘Objective To provide evidence for more accurate diagnosis of birth defects based on the pathoauatomy of congenital malformations. Methods Data used in this study were obtained fi＇om Luliang City Hospital and three county hospitals of Shanxi province between February 2004 and March 2006. Autopsy and pathological examination of 160 dead fetuses and stillbirths were performed. Photos of dead fetuses and stillbirths were taken, tissues were cut into sections for pathological examination under microscope, all pathological information was recorded, and percentage of birth defects was calculated. Results The proportion of dead fetuses and stillbirths with or without congenital malformations was 84.4% （135/160） and 15.6% （25/160）, respectively. There were 16 categories of major external and internal birth defects in 135 cases of such defects. Congenital heart defects, anencephaly and spina bifida had a higher prevalence rate in the study period. The prevalence rate of non-malformation death and birth defects 〈 28 gestational weeks and internal anomalies ≥ 28 gestational weeks was 14.61% （61/4175） and 17.25% （72/4175）, respectively. A total of 413 in situ anomalies were found in 135 cases of autopsy. Spina bifida, anencephaly, congenital heart defects, aplasia or accessory lobe of lung, renal agenesis and dysplasis and congenital hydrocephaly were more closely associated with severe malformations than with mitis malformations. The cases of dead fetuses and stillbirths with multiple malformations （/〉 2 in situ anomalies） had a higher proportion （74.1%）, whereas those with isolated malformations had a lower proportion （25.93%）. Conclusion The occurrence of congenital malformations in different embryonic developmental stages affects multiple organs. Postmortem examination of internal and multiple malformations of fetal deaths and stillbirths can provide more accurate diagnostic information for birth defects.
文摘Management of post-traumatic long-bone defects remains relevant and cha-llenging despite the rapid development of approaches to their treatment.Do-minant positions are occupied by the Ilizarov method,bone autogenous grafting and the Masquelet induced membrane technique(IMT).The IMT is aimed at reducing extensive defect treatment duration and for this reason has gained great popularity.However,the assessment of its effectiveness is difficult due to a limited number of clinical series.The varying clinical manifestations of bone defect severity do not allow a comprehensive evaluation of IMT effectiveness.One of them is infection in the defect area.The purpose of our literature review is an analysis of studies on IMT application in infected vs non-infected long-bone defects of the lower extremities published over the last 10 years.It focuses on the investigation of similarities and fundamental differences in the need for antibiotics,timing of spacer fixation,methods of collecting donor bone and fixators used for consolidation.The studies show that the IMT has been globally used in aseptic and osteomyelitic defects due to its clinical effectiveness.Authors’variations and improvements in its practical implementation indicate the ongoing development and the interest of researchers in this technique.
基金supported by the Samsung Research Funding&Incubation Center of Samsung Electronics under Project No.SRFC-MA2402-05supported by the KENTECH Center for Shared Research Facilities。
文摘The performance degradation of micro light-emitting diodes(micro-LEDs)is closely associated with the deterioration of sidewall passivation layers under prolonged electrical bias.We investigate reliability improvements in 20μm×20μm InGaN/GaN blue micro-LEDs by suppressing the formation of an unstable interfacial layer during sidewall passivation.SiO_(2)is deposited on the etched mesa sidewalls using either Sputtering or plasma-enhanced chemical vapor deposition(PECVD).Comparative analysis reveals that PECVD-passivated devices experience more severe performance degradation,primarily due to the increased leakage current.After 100 h of accelerated aging,external quantum efficiency decreases by 44%in PECVD-passivated samples,whereas Sputter-passivated devices exhibit only an11%reduction.This discrepancy is attributed to the formation of a thicker and chemically unstable gallium oxynitride(Ga-O_(X)-N_(1-X))interfacial layer at the SiO_(2)∕GaN-based interface,which facilitates the generation of sidewall defects.Suppressing the formation of this interlayer enhances the crystallinity and structural stability of the passivation layer,thereby mitigating the activation of point defects.Notably,Sputter deposition is more effective in minimizing the formation of Ga-O-N interlayer.These findings emphasize the critical role of achieving low-defect-density sidewall passivation to improve the reliability of micro-LEDs for next-generation high-resolution display applications.
基金the National Natural Science Foundation of China(81930057,81772076,81971836)the CAMS Innovation Fund for Medical Sciences(2019-I2M-5-076)+1 种基金the Deep Blue Talent Project of Naval Medical University,the 234 Academic Climbing Programme of Changhai Hospitalthe Achievements Supportive Fund(2018-CGPZ-B03).
文摘Background:Currently,various external tissue expansion devices are becoming widely used.Considering the scarcity of relevant application standards,this systematic review was performed to explore the effectiveness and safety of external tissue expansion techniques for the reconstruction of soft tissue defects.Method:A systematic review and meta-analysis on the efficacy and safety of external tissue expansion technique was conducted.A comprehensive search was performed in the following electronic databases:PubMed/Medline,Embase,Cochrane Library(Wiley Online Library),andWeb of Science.Studies reporting patients with soft tissue defects under the treatment of external tissue expansion technique were included.Results:A total of 66 studies with 22 different types of external tissue expansion devices met the inclusion criteria.We performed a descriptive analysis of different kinds of devices.A single-arm meta-analysis was performed to evaluate the efficacy and safety of the external tissue expansion technique for different aetiologies.The pooled mean wound healing time among patients with defects after fasciotomy was 10.548 days[95%confidence interval(CI)=5.796-15.299].The pooled median wound healing times of patients with defects after excisional surgery,trauma,chronic ulcers and abdominal defects were 11.218 days(95%CI=6.183-16.253),11.561 days(95%CI=7.062-16.060),15.956 days(95%CI=11.916-19.996)and 12.853 days(95%CI=9.444-16.227),respectively.The pooled wound healing rates of patients with defects after fasciotomy,excisional surgery,trauma,chronic ulcers and abdominal defects were 93.8%(95%CI=87.1-98.2%),97.2%(95%CI=92.2-99.7%),97.0%(95%CI=91.2-99.8%),99.5%(95%CI=97.6-100%),and 96.8%(95%CI=79.2-100%),respectively.We performed a subgroup analysis in patients with diabetic ulcers and open abdominal wounds.The pooled median wound healing time of patients with diabetic ulcers was 11.730 days(95%CI=10.334-13.125).The pooled median wound healing time of patients with open abdomen defects was 48.810 days(95%CI=35.557-62.063)and the pooled successful healing rate was 68.8%(95%CI=45.9-88.1%).A total of 1686 patients were included,265(15.7%)of whom experienced complications.The most common complication was dehiscence(n=53,3.14%).Conclusions:Our systematic review is the first to demonstrate the efficacy and safety of external tissue expansion in the management of soft tissue defects.However,we must interpret the meta-analysis results with caution considering the limitations of this review.Large-scale randomized controlled trials and long-term follow-up studies are still needed to confirm the effectiveness and evaluate the quality of healing.
基金Japan Government Cross-Ministerial Strategic Innovation Promotion Program-Smart Bio Industry and Agricultural Fundamental Technology(SIP-2:Consortium,Smart Food Chain).
文摘Non-invasive potato defects detection has been demanded for sorting and grading purpose.Researches on the classification of the defects has been available,however,investigation on the severity level calculation is limited.For the detection of the common scab,it has been found that imaging in the infrared region provide an interesting characteristic that could distinguish defected area to normal area.Thus,investigations on this wavelength range is interesting to add more knowledge and for applications.In this research,the multispectral image has been obtained and investigated especially at three wavelengths(950,1150,1600 nm).Image pre-processing and pseudo-color conversion techniques were explored to enhance the contrast between defects,normal background skin area and soil deposits.Results show that external defects,such as common scab and some mechanical damage types,appear brighter in the near infrared region,especially at 1600 nm against the normal skin background.It has been found that pseudo-color images conversion provides more information regarding type if surface characteristics compared to grayscale single imaging.Image segmentation using pseudo-color images after multiplication operation pre-processing could be used for common scab and mechanical damage detection excluding soil deposits with a Dice Sorensen coefficient of 0.64.In addition,image segmentation using single image at 1600 nm shown relatively better results with Dice Sorensen coefficient of 0.72 with note that thick soil deposits will also be segmented.Defect severity level evaluation had an R2 correlation of 0.84 against standard measurements of severity.
基金supported by the National Natural Science Foundation of China(Nos.21476007,21673197,21621091)the National Key R&D Program of China(No.2018YFA0209500)+4 种基金the 111 Project(No.B16029)the Fundamental Research Funds for the Central Universities of China(No.20720190037)the Natural Science Foundation of Fujian Province of China(No.2018J06003)the Special Project of Strategic Emerging Industries from Fujian Development and Reform CommissionChemcloudcomputing of Beijing University of Chemical Technology。
文摘The physicochemical properties of surfaces have a great effect on the micro-morphologies of the crystal structures which are in contact with them.Understanding the interaction mechanism between the internal driving forces of the crystal and external inducing forces of the surfaces is the prerequisite of controlling and obtaining the desirable morphologies.In this work,the dynamic density functional theory was applied to construct the free energy functional expression of polyethylene(PE)lattice,and the micro-dynamic evolution processes of PE lattice morphology near the surfaces with different properties were observed to reveal the interaction mechanism at atomic scale.The results showed that the physical and chemical properties of the external surfaces synergistically affect the morphologies in both the defect shapes and the distribution of the defect regions.In the absence of the contact surfaces,driven by the oriented interactions among different CH2 groups,PE lattices gradually grow and form a defect-free structure.Conversely,the presence of contact surfaces leads to lattice defects in the interfacial regions,and PE lattice shows different self-healing abilities around different surfaces.
文摘Objective: To explore the effect of external fixator and reconstituted bone xenograft (RBX) in the treatment of tibial bone defect, tibial bone nonunion and congenital pseudarthrosis of the tibia with limb shortening. Methods: Twenty patients ( 13 males and 7 females) with tibial bone defect, tibial bone nonunion or congenital pseudarthrosis of the tibia with limb shortening were treated with external fixation. Two kinds of external fixators were used: a half ring sulcated external fixator used in 13 patients and a combined external fixator in 7 patients. Foot-drop was corrected at the same time with external fixation in 4 patients. The shortened length of the tibia was in the range of 2-9 cm, with an average of 4.8 cm. For bone grafting, RBX was used in 12 patients, autogenous ilium was used in 3 patients and autogenous fibula was implanted as a bone plug into the medullary canal in 1 case, and no bone graft was used in 4 patients. Results: All the 20 patients were followed-up for 8 months to 7 years, averaging 51 months. Satisfactory function of the affected extremities was obtained. All the shortened extremities were lengthened to the expected length. For all the lengthening area and the fracture sites, bone union was obtained at the last. The average healing time of 12 patients treated with RBX was 4.8 months. Conclusions: Both the half ring sulcated external fixator and the combined external fixator have the advantages of small trauma, simple operation, elastic fixation without stress shielding and non-limitation from local soft tissue conditions, and there is satisfactory functional recovery of affected extremities in the treatment of tibial bone defects, tibial bone nonunion and congenital pseudarthrosis of the tibia combined with limb shortening. RBX has good biocompatibility and does not cause immunological rejections. It can also be safely used in treatment of bone nonunion and has reliable effect to promote bone healing.
