A liquid Li divertor is a promising alternative for future fusion devices.In this work a new divertor model is proposed,which is processed by 3D-printing technology to accurately control the size of the internal capil...A liquid Li divertor is a promising alternative for future fusion devices.In this work a new divertor model is proposed,which is processed by 3D-printing technology to accurately control the size of the internal capillary structure.At a steady-state heat load of 10 MW m^(-2),the thermal stress of the tungsten target is within the bearing range of tungsten by finite-element simulation.In order to evaluate the wicking ability of the capillary structure,the wicking process at 600℃ was simulated by FLUENT.The result was identical to that of the corresponding experiments.Within 1 s,liquid lithium was wicked to the target surface by the capillary structure of the target and quickly spread on the target surface.During the wicking process,the average wicking mass rate of lithium should reach 0.062 g s^(-1),which could even supplement the evaporation requirement of liquid lithium under an environment>950℃.Irradiation experiments under different plasma discharge currents were carried out in a linear plasma device(SCU-PSI),and the evolution of the vapor cloud during plasma irradiation was analyzed.It was found that the target temperature tends to plateau despite the gradually increased input current,indicating that the vapor shielding effect is gradually enhanced.The irradiation experiment also confirmed that the 3D-printed tungsten structure has better heat consumption performance than a tungsten mesh structure or multichannel structure.These results reveal the application potential and feasibility of a 3D-printed porous capillary structure in plasma-facing components and provide a reference for further liquid-solid combined target designs.展开更多
AIM:To assess the effect of experimentally induced anisometropia on binocularity in normal adults with glassesfree three-dimensional(3D)technique.METHODS:Totally 54 healthy medical students with normal binocularity in...AIM:To assess the effect of experimentally induced anisometropia on binocularity in normal adults with glassesfree three-dimensional(3D)technique.METHODS:Totally 54 healthy medical students with normal binocularity in the cross-sectional study were enrolled.Anisometropia was induced by placing trail lenses over the right eye,in 0.5 D steps including lenses of-0.5,-1,-1.5,-2,-2.5 D(hyperopic anisometropia)and lenses of+0.5,+1,+1.5,+2,+2.5 D(myopic anisometropia).The glasses-free 3D technique was used to evaluated not only fine stereopsis,but also coarse stereopsis,dynamic stereopsis,foveal suppression,and peripheral suppression in these subjects.One-way analysis of variance was used to compare quantitative data such as fine stereopsis,coarse stereopsis.Pearson’s Chi-square test was performed to compare categorical data such as dynamic stereopsis,foveal suppression and peripheral suppression.RESULTS:The subjects showed a statistically significant decline in fine stereopsis,coarse stereopsis,and dynamic stereopsis with increasing levels of anisometropia(P<0.001).Binocularity was af fected when induced anisometropia was more than 1 D(P<0.05).Foveal suppression and peripheral suppression were evident and increased in proportion to anisometropia(P<0.001).CONCLUSION:The relatively low degrees of anisometropia may have a potentially significant effect on high-grade binocular interaction.The mechanisms underlying the defect of binocularity seem to involve not only foveal suppression,but also peripheral suppression.展开更多
Superconducting YBa_(2)Cu_(3)O_(7−x)(YBCO)bulks have promising applications in quasi-permanent magnets,levitation,etc.Recently,a new way of fabricating porous YBCO bulks,named direct-ink-writing(DIW)3D-printing method...Superconducting YBa_(2)Cu_(3)O_(7−x)(YBCO)bulks have promising applications in quasi-permanent magnets,levitation,etc.Recently,a new way of fabricating porous YBCO bulks,named direct-ink-writing(DIW)3D-printing method,has been reported.In this method,the customized precursor paste and programmable shape are two main advantages.Here,we have put forward a new way to customize the YBCO 3D-printing precursor paste which is doped with Al_(2)O_(3)nanoparticles to obtain YBCO with higher thermal conductivity.The great rheological properties of precursor paste after being doped with Al_(2)O_(3)nanoparticles can help the macroscopic YBCO samples with high thermal conductivity fabricated stably with high crystalline and lightweight properties.Test results show that the peak thermal conductivity of Al_(2)O_(3)-doped YBCO can reach twice as much as pure YBCO,which makes a great effort to reduce the quench propagation speed.Based on the microstructure analysis,one can find that the thermal conductivity of Al_(2)O_(3)-doped YBCO has been determined by its components and microstructures.In addition,a macroscopic theoretical model has been proposed to assess the thermal conductivity of different microstructures,whose calculated results take good agreement with the experimental results.Meanwhile,a microstructure with high thermal conductivity has been found.Finally,a macroscopic YBCO bulk with the presented high thermal conductivity microstructure has been fabricated by the Al_(2)O_(3)-doped method.Compared with YBCO fabricated by the traditional 3D-printed,the Al_(2)O_(3)-doped structural YBCO bulks present excellent heat transfer performances.Our customized design of 3D-printing precursor pastes and novel concept of structural design for enhancing the thermal conductivity of YBCO superconducting material can be widely used in other DIW 3D-printing materials.展开更多
BACKGROUND Hernia is a common condition requiring abdominal surgery.The current standard treatment for hernia is tension-free repair using meshes.Globally,more than 200 new types of meshes are licensed each year.Howev...BACKGROUND Hernia is a common condition requiring abdominal surgery.The current standard treatment for hernia is tension-free repair using meshes.Globally,more than 200 new types of meshes are licensed each year.However,their clinical applications are associated with a series of complications,such as recurrence(10%-24%)and infection(0.5%-9.0%).In contrast,3D-printed meshes have significantly reduced the postoperative complications in patients.They have also shortened operating time and minimized the loss of mesh materials.In this study,we used the myopectineal orifice(MPO)data obtained from preoperative computer tomography(CT)-based 3D reconstruction for the production of 3D-printed biologic meshes.AIM To investigate the application of multislice spiral CT-based 3D reconstruction technique in 3D-printed biologic mesh for hernia repair surgery.METHODS We retrospectively analyzed 60 patients who underwent laparoscopic tension-free repair for inguinal hernia in the Department of General Surgery of the First Hospital of Shanxi Medical University from September 2019 to December 2019.This study included 30 males and 30 females,with a mean age of 40±5.6 years.Data on the MPO were obtained from preoperative CT-based 3D reconstruction as well as from real-world intraoperative measurements for all patients.Anatomic points were set for the purpose of measurement based on the definition of MPO:A:The pubic tubercle;B:Intersection of the horizontal line extending from the summit of the inferior edge of the internal oblique and transversus abdominis and the outer edge of the rectus abdominis,C:Intersection of the horizontal line extending from the summit of the inferior edge of the internal oblique and transversus abdominis and the inguinal ligament,D:Intersection of the iliopsoas muscle and the inguinal ligament,and E:Intersection of the iliopsoas muscle and the superior pubic ramus.The distance between the points was measured.All preoperative and intraoperative data were analyzed using the t test.Differences with P<0.05 were considered significant in comparative analysis.RESULTS The distance between points AB,AC,BC,DE,and AE based on preoperative and intraoperative data was 7.576±0.212 cm vs 7.573±0.266 cm,7.627±0.212 cm vs 7.627±0.212 cm,7.677±0.229 cm vs 7.567±0.786 cm,7.589±0.204 cm vs 7.512±0.21 cm,and 7.617±0.231 cm vs 7.582±0.189 cm,respectively.All differences were not statistically significant(P>0.05).CONCLUSION The use of multislice spiral CT-based 3D reconstruction technique before hernia repair surgery allows accurate measurement of data and relationships of different anatomic sites in the MPO region.This technique can provide precise data for the production of 3D-printed biologic meshes.展开更多
Due to the pristine interface of the 2D/3D face-tunneling heterostructure with an ultra-sharp doping profile, the 2D/3D tunneling field-effect transistor(TFET) is considered as one of the most promising low-power devi...Due to the pristine interface of the 2D/3D face-tunneling heterostructure with an ultra-sharp doping profile, the 2D/3D tunneling field-effect transistor(TFET) is considered as one of the most promising low-power devices that can simultaneously obtain low off-state current(IOFF), high on-state current(ION) and steep subthreshold swing(SS). As a key element for the 2D/3D TFET, the intensive exploration of the tunnel diode based on the 2D/3D heterostructure is in urgent need.The transfer technique composed of the exfoliation and the release process is currently the most common approach to fabricating the 2D/3D heterostructures. However, the well-established transfer technique of the 2D materials is still unavailable.Only a small part of the irregular films can usually be obtained by mechanical exfoliation, while the choice of the chemical exfoliation may lead to the contamination of the 2D material films by the ions in the chemical etchants. Moreover, the deformation of the 2D material in the transfer process due to its soft nature also leads to the nonuniformity of the transferred film,which is one of the main reasons for the presence of the wrinkles and the stacks in the transferred film. Thus, the large-scale fabrication of the high-quality 2D/3D tunnel diodes is limited. In this article, a comprehensive transfer technique that can mend up the shortages mentioned above with the aid of the water and the thermal release tape(TRT) is proposed. Based on the method we proposed, the MoS_(2)/Si tunnel diode is experimentally demonstrated and the transferred monolayer MoS_(2) film with the relatively high crystal quality is confirmed by atomic force microscopy(AFM), scanning electron microscopy(SEM), and Raman characterizations. Besides, the prominent negative differential resistance(NDR) effect is observed at room temperature, which verifies the relatively high quality of the MoS_(2)/Si heterojunction. The bilayer MoS_(2)/Si tunnel diode is also experimentally fabricated by repeating the transfer process we proposed, followed by the specific analysis of the electrical characteristics. This study shows the advantages of the transfer technique we proposed and indicates the great application foreground of the fabricated 2D/3D heterostructure for ultralow-power tunneling devices.展开更多
Objective: To investigate the value of 3D printing techniques in the treatment of complex tibial plateau fractures. Methods: From September 2016 to September 2018, 28 patients with complex tibial plateau fractures wer...Objective: To investigate the value of 3D printing techniques in the treatment of complex tibial plateau fractures. Methods: From September 2016 to September 2018, 28 patients with complex tibial plateau fractures were treated in our hospital. According to the odevity of hospitalized order, the patients were divided into two groups. Group A used 3D reconstruction, virtually reduction, 3D printing and demonstration of individual fracture model before operation while group B only received conventional process by use X-rays or CT image. Comparison between the two groups was made in operation time, operative blood loss, radiation frequency, surgery instrument cost and knee function score. Results: The follow-up was 14.4 months on average (ranged 6 to 22 months). There was no statistical difference of the surgery instrument cost between the 2 groups (P > 0.05). The operation time of group A was significantly shorter than that of group B (P χ2 = 0.373, P = 0.54). Conclusion: 3D printing techniques can improve surgery effect in complex tibial plateau fractures.展开更多
The kinetics and the difference for Pr(Ⅲ)and Nd(Ⅲ)extraction from nitrate aqueous solution using trialkylmethylammonium nitrate([A336][NO3])as extractant were investigated by the single drop technique.The dependence...The kinetics and the difference for Pr(Ⅲ)and Nd(Ⅲ)extraction from nitrate aqueous solution using trialkylmethylammonium nitrate([A336][NO3])as extractant were investigated by the single drop technique.The dependence of the extraction rate of Pr(Ⅲ)and Nd(Ⅲ)on the concentrations of free Pr(Ⅲ)and Nd(Ⅲ)ions,the concentrations of Na NO3 and H+in aqueous solutions,and the concentrations of[A336][NO3]in kerosene solutions were discussed and the corresponding extraction rate equations for Pr(Ⅲ)and Nd(Ⅲ)were obtained.These equations demonstrated that the reaction rate constant of Pr(Ⅲ)with[A336][NO3]was double than that of Nd(Ⅲ).The effect of the addition of diethylenetriaminepentaacetic acid(DTPA)on the difference in the extraction rate of Pr(Ⅲ)and Nd(Ⅲ)by[A336][NO3]was also investigated.It was revealed that the difference in the complex formation rates of Pr(Ⅲ)and Nd(Ⅲ)with DTPA made a significant impact on the difference in the extraction rates of Pr(Ⅲ)and Nd(Ⅲ)with[A336][NO3].The ratio of extraction rates of Pr(Ⅲ)to Nd(Ⅲ)with[A336][NO3]was in proportion to the ratio of complex formation rates of Pr(Ⅲ)to Nd(Ⅲ)with DTPA.The extraction rate difference for Pr(Ⅲ)and Nd(Ⅲ)with[A336][NO3]increased due to a higher complex formation rate constant of DTPA with the free and un-complexed Nd(Ⅲ)ions in the aqueous nitrate solution than that with Pr(Ⅲ)ions.Therefore,the addition of DTPA in the aqueous nitrate solution is an effective method to intensify the separation of Pr(Ⅲ)and Nd(Ⅲ)in kinetics.The study on the extraction mechanism indicated that both the extraction of Pr(Ⅲ)and Nd(Ⅲ)by[A336][NO3]were diffusion controlled,and the reactions obeyed SN2 mechanism.The present work highlights a possible approach to strengthen the kinetic separation of Pr(Ⅲ)and Nd(Ⅲ).展开更多
Due to the attractive performances such as the ability of beam focus,broadband,multi-beam scanning and other features,Luneburg lens antennas are applied in multi-beam antenna,which overcomes the problem of gain loss p...Due to the attractive performances such as the ability of beam focus,broadband,multi-beam scanning and other features,Luneburg lens antennas are applied in multi-beam antenna,which overcomes the problem of gain loss produced by multi-beam parabolic antenna.Based on 3-D printing technique,Luneburg lens antennas by drilling holes are studied.Permittivity and loss tangent of the equivalent lens materials can be influenced by original materials,hole shapes,hole directions,and porosity.After tests,polystyrene with waxes may be the most appropriate materials for Luneburg lens with high strength.Permittivity with the shape of triangle is the lowest due to the homogeneity.Relative permittivities with the direction at a range of 15°-45°are lower while loss tangent at a range of 0°-30°.Radial directional holes are more appropriate for Luneburg lens.The relative permittivity is decreased with the increment of porosity.After calculations,the forecasts calculated by Looyenga and A-BG theory are more precise.Finally,Luneburg lens with two layers is fabricated by 3-D printing.展开更多
Thin films of poly（3-hexadecyl pyrrole） （P3HDP） nanoparticles have been fabricated by using Langmuir-Blodgett film deposition technique. The structures and morphology of the films were studied by using infrared sp...Thin films of poly（3-hexadecyl pyrrole） （P3HDP） nanoparticles have been fabricated by using Langmuir-Blodgett film deposition technique. The structures and morphology of the films were studied by using infrared spectroscopy, scanning and transmission microscopes. The experimental results demonstrated that the nanoparticles were formed by self-assembling P3HDP at air-water surface. The water contact angles of these films with different deposition layers were measured to be as high as 110°.展开更多
In this paper, instead of with the more expensive Fourier Transform Infrared Spectrometer(FTIR) a new technique of Temperature Programmed Transient Response(TP-TR) has been used with gas chromatography. Therefore, the...In this paper, instead of with the more expensive Fourier Transform Infrared Spectrometer(FTIR) a new technique of Temperature Programmed Transient Response(TP-TR) has been used with gas chromatography. Therefore, the TP-TR will be applied more widespreadly than ever before. With the technique of TP-TR and electric conductivity, the study is on the reaction mechanism and the adsorption behavior of the reactants and products to the present catalyst Mo-V-Nb/Al_2O_3 in the reaction from ethane through oxydehydrogenation to ethylene as the product. By Range-Kutta-Gill and Margarat methods, the kinetic parameters of the reaction elementary steps (i.e. rate constants, active energies and frequency factors) have been evaluated. The mathematical treatment coincides with the experimental results.展开更多
Based on the established mathematic model and graphic interpretation, a new method, which is used to calculate the contribution of single-zone production in a commingled producing well by the ultraviolet spectrum tech...Based on the established mathematic model and graphic interpretation, a new method, which is used to calculate the contribution of single-zone production in a commingled producing well by the ultraviolet spectrum technique, has been established. The standard plate was drawn using the extinction coefficient E of sample oils formulated artificially as y-axis and the wavelength as x-axis. The curve resulting from the UV analysis of sample oils in the commingled well was inserted into the standard plate and compared. The proportion of each single zone in the commingled producing well was identical with the proportion of the curve which is closest to the curve of sample oils formulated artificially. In the well QHD32-6-3 field, taking well A22 for example and using this method, the production contribution of a single zone was calculated. The result showed that the Nm4 zone is a major "contributor", the proportion of the Nm4 zone is 70%, and that of the Nm1 zone is 30%. The ultraviolet spectrum technique provided a new reservoir geochemical technique of monitoring production contribution, especially for biodegraded heavy oil, but it has some limitation, just depending on the GC fingerprint technique.展开更多
Objective To investigate the effect of computer aided 3D simulation technique for treating complicated foot and ankle fractures precisely.Methods From November 2007 to August 2009,255 patients with complicated foot an...Objective To investigate the effect of computer aided 3D simulation technique for treating complicated foot and ankle fractures precisely.Methods From November 2007 to August 2009,255 patients with complicated foot and ankle fractures展开更多
Enterocutaneous fistulas(ECFs) are great challenges during the open abdomen. The loss of digestive juice, water-electrolyte imbalance and malnutrition are intractable issues during management of ECF. Techniques such a...Enterocutaneous fistulas(ECFs) are great challenges during the open abdomen. The loss of digestive juice, water-electrolyte imbalance and malnutrition are intractable issues during management of ECF. Techniques such as "fistula patch" and vacuumassisted closure therapy have been applied to prevent contamination of open abdominal wounds by intestinal fistula drainage. However, failures are encountered due to high-output fistula and anatomical complexity. Here, we report 3 D-printed patient-personalized fistula stent for ECF treatment based on 3 D reconstruction of the fistula image. Subsequent follow-up demonstrated that this stent was well-implanted and effective to reduce the volume of enteric fistula effluent.展开更多
基金funded by the China Postdoctoral Science Foundation(No.2019M663487)the National Key Research and Development Program of China(No.2022YFE03130000)。
文摘A liquid Li divertor is a promising alternative for future fusion devices.In this work a new divertor model is proposed,which is processed by 3D-printing technology to accurately control the size of the internal capillary structure.At a steady-state heat load of 10 MW m^(-2),the thermal stress of the tungsten target is within the bearing range of tungsten by finite-element simulation.In order to evaluate the wicking ability of the capillary structure,the wicking process at 600℃ was simulated by FLUENT.The result was identical to that of the corresponding experiments.Within 1 s,liquid lithium was wicked to the target surface by the capillary structure of the target and quickly spread on the target surface.During the wicking process,the average wicking mass rate of lithium should reach 0.062 g s^(-1),which could even supplement the evaporation requirement of liquid lithium under an environment>950℃.Irradiation experiments under different plasma discharge currents were carried out in a linear plasma device(SCU-PSI),and the evolution of the vapor cloud during plasma irradiation was analyzed.It was found that the target temperature tends to plateau despite the gradually increased input current,indicating that the vapor shielding effect is gradually enhanced.The irradiation experiment also confirmed that the 3D-printed tungsten structure has better heat consumption performance than a tungsten mesh structure or multichannel structure.These results reveal the application potential and feasibility of a 3D-printed porous capillary structure in plasma-facing components and provide a reference for further liquid-solid combined target designs.
基金Supported by Sichuan Science and Technology Program (No.23NSFSC0856)。
文摘AIM:To assess the effect of experimentally induced anisometropia on binocularity in normal adults with glassesfree three-dimensional(3D)technique.METHODS:Totally 54 healthy medical students with normal binocularity in the cross-sectional study were enrolled.Anisometropia was induced by placing trail lenses over the right eye,in 0.5 D steps including lenses of-0.5,-1,-1.5,-2,-2.5 D(hyperopic anisometropia)and lenses of+0.5,+1,+1.5,+2,+2.5 D(myopic anisometropia).The glasses-free 3D technique was used to evaluated not only fine stereopsis,but also coarse stereopsis,dynamic stereopsis,foveal suppression,and peripheral suppression in these subjects.One-way analysis of variance was used to compare quantitative data such as fine stereopsis,coarse stereopsis.Pearson’s Chi-square test was performed to compare categorical data such as dynamic stereopsis,foveal suppression and peripheral suppression.RESULTS:The subjects showed a statistically significant decline in fine stereopsis,coarse stereopsis,and dynamic stereopsis with increasing levels of anisometropia(P<0.001).Binocularity was af fected when induced anisometropia was more than 1 D(P<0.05).Foveal suppression and peripheral suppression were evident and increased in proportion to anisometropia(P<0.001).CONCLUSION:The relatively low degrees of anisometropia may have a potentially significant effect on high-grade binocular interaction.The mechanisms underlying the defect of binocularity seem to involve not only foveal suppression,but also peripheral suppression.
基金supported by the Fund of Natural Science Foundation of China(No.11872196,12232005)supported by the Outstanding Postgraduate‘Innovation Star’Fund for Distinguished of Gansu Province(No.2021CXZX-032).
文摘Superconducting YBa_(2)Cu_(3)O_(7−x)(YBCO)bulks have promising applications in quasi-permanent magnets,levitation,etc.Recently,a new way of fabricating porous YBCO bulks,named direct-ink-writing(DIW)3D-printing method,has been reported.In this method,the customized precursor paste and programmable shape are two main advantages.Here,we have put forward a new way to customize the YBCO 3D-printing precursor paste which is doped with Al_(2)O_(3)nanoparticles to obtain YBCO with higher thermal conductivity.The great rheological properties of precursor paste after being doped with Al_(2)O_(3)nanoparticles can help the macroscopic YBCO samples with high thermal conductivity fabricated stably with high crystalline and lightweight properties.Test results show that the peak thermal conductivity of Al_(2)O_(3)-doped YBCO can reach twice as much as pure YBCO,which makes a great effort to reduce the quench propagation speed.Based on the microstructure analysis,one can find that the thermal conductivity of Al_(2)O_(3)-doped YBCO has been determined by its components and microstructures.In addition,a macroscopic theoretical model has been proposed to assess the thermal conductivity of different microstructures,whose calculated results take good agreement with the experimental results.Meanwhile,a microstructure with high thermal conductivity has been found.Finally,a macroscopic YBCO bulk with the presented high thermal conductivity microstructure has been fabricated by the Al_(2)O_(3)-doped method.Compared with YBCO fabricated by the traditional 3D-printed,the Al_(2)O_(3)-doped structural YBCO bulks present excellent heat transfer performances.Our customized design of 3D-printing precursor pastes and novel concept of structural design for enhancing the thermal conductivity of YBCO superconducting material can be widely used in other DIW 3D-printing materials.
基金Supported by the Shanxi Provincial Key Research and Development Program,No.201903D321175.
文摘BACKGROUND Hernia is a common condition requiring abdominal surgery.The current standard treatment for hernia is tension-free repair using meshes.Globally,more than 200 new types of meshes are licensed each year.However,their clinical applications are associated with a series of complications,such as recurrence(10%-24%)and infection(0.5%-9.0%).In contrast,3D-printed meshes have significantly reduced the postoperative complications in patients.They have also shortened operating time and minimized the loss of mesh materials.In this study,we used the myopectineal orifice(MPO)data obtained from preoperative computer tomography(CT)-based 3D reconstruction for the production of 3D-printed biologic meshes.AIM To investigate the application of multislice spiral CT-based 3D reconstruction technique in 3D-printed biologic mesh for hernia repair surgery.METHODS We retrospectively analyzed 60 patients who underwent laparoscopic tension-free repair for inguinal hernia in the Department of General Surgery of the First Hospital of Shanxi Medical University from September 2019 to December 2019.This study included 30 males and 30 females,with a mean age of 40±5.6 years.Data on the MPO were obtained from preoperative CT-based 3D reconstruction as well as from real-world intraoperative measurements for all patients.Anatomic points were set for the purpose of measurement based on the definition of MPO:A:The pubic tubercle;B:Intersection of the horizontal line extending from the summit of the inferior edge of the internal oblique and transversus abdominis and the outer edge of the rectus abdominis,C:Intersection of the horizontal line extending from the summit of the inferior edge of the internal oblique and transversus abdominis and the inguinal ligament,D:Intersection of the iliopsoas muscle and the inguinal ligament,and E:Intersection of the iliopsoas muscle and the superior pubic ramus.The distance between the points was measured.All preoperative and intraoperative data were analyzed using the t test.Differences with P<0.05 were considered significant in comparative analysis.RESULTS The distance between points AB,AC,BC,DE,and AE based on preoperative and intraoperative data was 7.576±0.212 cm vs 7.573±0.266 cm,7.627±0.212 cm vs 7.627±0.212 cm,7.677±0.229 cm vs 7.567±0.786 cm,7.589±0.204 cm vs 7.512±0.21 cm,and 7.617±0.231 cm vs 7.582±0.189 cm,respectively.All differences were not statistically significant(P>0.05).CONCLUSION The use of multislice spiral CT-based 3D reconstruction technique before hernia repair surgery allows accurate measurement of data and relationships of different anatomic sites in the MPO region.This technique can provide precise data for the production of 3D-printed biologic meshes.
基金Project supported by the National Natural Science Foundation of China (Grant No.61851405)。
文摘Due to the pristine interface of the 2D/3D face-tunneling heterostructure with an ultra-sharp doping profile, the 2D/3D tunneling field-effect transistor(TFET) is considered as one of the most promising low-power devices that can simultaneously obtain low off-state current(IOFF), high on-state current(ION) and steep subthreshold swing(SS). As a key element for the 2D/3D TFET, the intensive exploration of the tunnel diode based on the 2D/3D heterostructure is in urgent need.The transfer technique composed of the exfoliation and the release process is currently the most common approach to fabricating the 2D/3D heterostructures. However, the well-established transfer technique of the 2D materials is still unavailable.Only a small part of the irregular films can usually be obtained by mechanical exfoliation, while the choice of the chemical exfoliation may lead to the contamination of the 2D material films by the ions in the chemical etchants. Moreover, the deformation of the 2D material in the transfer process due to its soft nature also leads to the nonuniformity of the transferred film,which is one of the main reasons for the presence of the wrinkles and the stacks in the transferred film. Thus, the large-scale fabrication of the high-quality 2D/3D tunnel diodes is limited. In this article, a comprehensive transfer technique that can mend up the shortages mentioned above with the aid of the water and the thermal release tape(TRT) is proposed. Based on the method we proposed, the MoS_(2)/Si tunnel diode is experimentally demonstrated and the transferred monolayer MoS_(2) film with the relatively high crystal quality is confirmed by atomic force microscopy(AFM), scanning electron microscopy(SEM), and Raman characterizations. Besides, the prominent negative differential resistance(NDR) effect is observed at room temperature, which verifies the relatively high quality of the MoS_(2)/Si heterojunction. The bilayer MoS_(2)/Si tunnel diode is also experimentally fabricated by repeating the transfer process we proposed, followed by the specific analysis of the electrical characteristics. This study shows the advantages of the transfer technique we proposed and indicates the great application foreground of the fabricated 2D/3D heterostructure for ultralow-power tunneling devices.
文摘Objective: To investigate the value of 3D printing techniques in the treatment of complex tibial plateau fractures. Methods: From September 2016 to September 2018, 28 patients with complex tibial plateau fractures were treated in our hospital. According to the odevity of hospitalized order, the patients were divided into two groups. Group A used 3D reconstruction, virtually reduction, 3D printing and demonstration of individual fracture model before operation while group B only received conventional process by use X-rays or CT image. Comparison between the two groups was made in operation time, operative blood loss, radiation frequency, surgery instrument cost and knee function score. Results: The follow-up was 14.4 months on average (ranged 6 to 22 months). There was no statistical difference of the surgery instrument cost between the 2 groups (P > 0.05). The operation time of group A was significantly shorter than that of group B (P χ2 = 0.373, P = 0.54). Conclusion: 3D printing techniques can improve surgery effect in complex tibial plateau fractures.
基金financially supported by the National Natural Science Foundation of China(Nos.51574213,51074150)the Key Project of Chinese National Programs for Fundamental Research and Development(973 Program No.2012CBA01203)。
文摘The kinetics and the difference for Pr(Ⅲ)and Nd(Ⅲ)extraction from nitrate aqueous solution using trialkylmethylammonium nitrate([A336][NO3])as extractant were investigated by the single drop technique.The dependence of the extraction rate of Pr(Ⅲ)and Nd(Ⅲ)on the concentrations of free Pr(Ⅲ)and Nd(Ⅲ)ions,the concentrations of Na NO3 and H+in aqueous solutions,and the concentrations of[A336][NO3]in kerosene solutions were discussed and the corresponding extraction rate equations for Pr(Ⅲ)and Nd(Ⅲ)were obtained.These equations demonstrated that the reaction rate constant of Pr(Ⅲ)with[A336][NO3]was double than that of Nd(Ⅲ).The effect of the addition of diethylenetriaminepentaacetic acid(DTPA)on the difference in the extraction rate of Pr(Ⅲ)and Nd(Ⅲ)by[A336][NO3]was also investigated.It was revealed that the difference in the complex formation rates of Pr(Ⅲ)and Nd(Ⅲ)with DTPA made a significant impact on the difference in the extraction rates of Pr(Ⅲ)and Nd(Ⅲ)with[A336][NO3].The ratio of extraction rates of Pr(Ⅲ)to Nd(Ⅲ)with[A336][NO3]was in proportion to the ratio of complex formation rates of Pr(Ⅲ)to Nd(Ⅲ)with DTPA.The extraction rate difference for Pr(Ⅲ)and Nd(Ⅲ)with[A336][NO3]increased due to a higher complex formation rate constant of DTPA with the free and un-complexed Nd(Ⅲ)ions in the aqueous nitrate solution than that with Pr(Ⅲ)ions.Therefore,the addition of DTPA in the aqueous nitrate solution is an effective method to intensify the separation of Pr(Ⅲ)and Nd(Ⅲ)in kinetics.The study on the extraction mechanism indicated that both the extraction of Pr(Ⅲ)and Nd(Ⅲ)by[A336][NO3]were diffusion controlled,and the reactions obeyed SN2 mechanism.The present work highlights a possible approach to strengthen the kinetic separation of Pr(Ⅲ)and Nd(Ⅲ).
基金supported by the Science and Technology Programme of Shijiazhuang under Grant 151130081A
文摘Due to the attractive performances such as the ability of beam focus,broadband,multi-beam scanning and other features,Luneburg lens antennas are applied in multi-beam antenna,which overcomes the problem of gain loss produced by multi-beam parabolic antenna.Based on 3-D printing technique,Luneburg lens antennas by drilling holes are studied.Permittivity and loss tangent of the equivalent lens materials can be influenced by original materials,hole shapes,hole directions,and porosity.After tests,polystyrene with waxes may be the most appropriate materials for Luneburg lens with high strength.Permittivity with the shape of triangle is the lowest due to the homogeneity.Relative permittivities with the direction at a range of 15°-45°are lower while loss tangent at a range of 0°-30°.Radial directional holes are more appropriate for Luneburg lens.The relative permittivity is decreased with the increment of porosity.After calculations,the forecasts calculated by Looyenga and A-BG theory are more precise.Finally,Luneburg lens with two layers is fabricated by 3-D printing.
基金This work was supported by the National Natural Science Foundation of China (Nos. 50225311, 20374034, 50133010) and 973 Project (No. 2003CB615700).
文摘Thin films of poly（3-hexadecyl pyrrole） （P3HDP） nanoparticles have been fabricated by using Langmuir-Blodgett film deposition technique. The structures and morphology of the films were studied by using infrared spectroscopy, scanning and transmission microscopes. The experimental results demonstrated that the nanoparticles were formed by self-assembling P3HDP at air-water surface. The water contact angles of these films with different deposition layers were measured to be as high as 110°.
文摘In this paper, instead of with the more expensive Fourier Transform Infrared Spectrometer(FTIR) a new technique of Temperature Programmed Transient Response(TP-TR) has been used with gas chromatography. Therefore, the TP-TR will be applied more widespreadly than ever before. With the technique of TP-TR and electric conductivity, the study is on the reaction mechanism and the adsorption behavior of the reactants and products to the present catalyst Mo-V-Nb/Al_2O_3 in the reaction from ethane through oxydehydrogenation to ethylene as the product. By Range-Kutta-Gill and Margarat methods, the kinetic parameters of the reaction elementary steps (i.e. rate constants, active energies and frequency factors) have been evaluated. The mathematical treatment coincides with the experimental results.
文摘Based on the established mathematic model and graphic interpretation, a new method, which is used to calculate the contribution of single-zone production in a commingled producing well by the ultraviolet spectrum technique, has been established. The standard plate was drawn using the extinction coefficient E of sample oils formulated artificially as y-axis and the wavelength as x-axis. The curve resulting from the UV analysis of sample oils in the commingled well was inserted into the standard plate and compared. The proportion of each single zone in the commingled producing well was identical with the proportion of the curve which is closest to the curve of sample oils formulated artificially. In the well QHD32-6-3 field, taking well A22 for example and using this method, the production contribution of a single zone was calculated. The result showed that the Nm4 zone is a major "contributor", the proportion of the Nm4 zone is 70%, and that of the Nm1 zone is 30%. The ultraviolet spectrum technique provided a new reservoir geochemical technique of monitoring production contribution, especially for biodegraded heavy oil, but it has some limitation, just depending on the GC fingerprint technique.
文摘Objective To investigate the effect of computer aided 3D simulation technique for treating complicated foot and ankle fractures precisely.Methods From November 2007 to August 2009,255 patients with complicated foot and ankle fractures
基金Supported by the National Natural Science Foundation of China,No.81571881
文摘Enterocutaneous fistulas(ECFs) are great challenges during the open abdomen. The loss of digestive juice, water-electrolyte imbalance and malnutrition are intractable issues during management of ECF. Techniques such as "fistula patch" and vacuumassisted closure therapy have been applied to prevent contamination of open abdominal wounds by intestinal fistula drainage. However, failures are encountered due to high-output fistula and anatomical complexity. Here, we report 3 D-printed patient-personalized fistula stent for ECF treatment based on 3 D reconstruction of the fistula image. Subsequent follow-up demonstrated that this stent was well-implanted and effective to reduce the volume of enteric fistula effluent.
