Background Physical entity interactions in mixed reality(MR)environments aim to harness human capabilities in manipulating physical objects,thereby enhancing virtual environment(VEs)functionality.In MR,a common strate...Background Physical entity interactions in mixed reality(MR)environments aim to harness human capabilities in manipulating physical objects,thereby enhancing virtual environment(VEs)functionality.In MR,a common strategy is to use virtual agents as substitutes for physical entities,balancing interaction efficiency with environmental immersion.However,the impact of virtual agent size and form on interaction performance remains unclear.Methods Two experiments were conducted to explore how virtual agent size and form affect interaction performance,immersion,and preference in MR environments.The first experiment assessed five virtual agent sizes(25%,50%,75%,100%,and 125%of physical size).The second experiment tested four types of frames(no frame,consistent frame,half frame,and surrounding frame)across all agent sizes.Participants,utilizing a head mounted display,performed tasks involving moving cups,typing words,and using a mouse.They completed questionnaires assessing aspects such as the virtual environment effects,interaction effects,collision concerns,and preferences.Results Results from the first experiment revealed that agents matching physical object size produced the best overall performance.The second experiment demonstrated that consistent framing notably enhances interaction accuracy and speed but reduces immersion.To balance efficiency and immersion,frameless agents matching physical object sizes were deemed optimal.Conclusions Virtual agents matching physical entity sizes enhance user experience and interaction performance.Conversely,familiar frames from 2D interfaces detrimentally affect interaction and immersion in virtual spaces.This study provides valuable insights for the future development of MR systems.展开更多
The power density of electronic components grows continuously,and the subsequent heat accumulation and temperature increase inevitably affect electronic equipment’s stability,reliability and service life.Therefore,ac...The power density of electronic components grows continuously,and the subsequent heat accumulation and temperature increase inevitably affect electronic equipment’s stability,reliability and service life.Therefore,achieving efficient cooling in limited space has become a key problem in updating electronic devices with high performance and high integration.Two-phase immersion is a novel cooling method.The computational fluid dynamics(CFD)method is used to investigate the cooling performance of two-phase immersion cooling on high-power electronics.The two-dimensional CFD model is utilized by the volume of fluid(VOF)method and Reynolds StressModel.Lee’s model was employed to calculate the phase change rate.The heat transfer coefficient along the heatedwalls and the shear-lift force on bubbles are calculated.The simulation data are verified with the literature results.The cooling performance of different coolants has been studied.The results indicate that the boiling heat transfer coefficient can be enhanced by using a low boiling point coolant.The methanol is used as the cooling medium for further research.In addition,the mass flow rate and inlet temperature are investigated to assess the thermal performance of twophase immersion cooling.The average temperature of the high-power electronics is 80℃,and the temperature difference can be constrained to 8℃.Meanwhile,the convective heat transfer coefficient reaches 2740 W/(m2・℃)when the inlet temperature is 50℃,and the mass flow rate is 0.3 kg/s.In conclusion,the results demonstrated that two-phase immersion cooling has provided an effective method for the thermal management of high-power electronics.展开更多
In this paper, we deal with isommetric immersions of globally null warped product manifolds into Lorentzian manifolds with constant curvature c in codimension k≥3. Under the assumptions that the globally null warped ...In this paper, we deal with isommetric immersions of globally null warped product manifolds into Lorentzian manifolds with constant curvature c in codimension k≥3. Under the assumptions that the globally null warped product manifold has no points with the same constant sectional curvature c as the Lorentzian ambient, we show that such isometric immersion splits into warped product of isometric immersions.展开更多
A nickel-based coating was deposited on the pure Al substrate by immersion plating,and the Al/Cu bimetals were prepared by diffusion bonding in the temperature range of 450-550 ℃.The interce microstructure and fractu...A nickel-based coating was deposited on the pure Al substrate by immersion plating,and the Al/Cu bimetals were prepared by diffusion bonding in the temperature range of 450-550 ℃.The interce microstructure and fracture surface of Al/Cu joints were studied by scanning electron microscopy（SEM） and X-ray diffraction（XRD）.The mechanical properties of the Al/Cu bimetals were measured by tensile shear and microhardness tests.The results show that the Ni interiayer can effectively eliminate the formation of Al-Cu intermetallic compounds.The Al/Ni interface consists of the Al3Ni and Al3Ni2 phases,while it is Ni-Cu solid solution at the Ni/Cu interce.The tensile shear strength of the joints is improved by the addition of Ni interiayer.The joint with Ni interiayer annealed at 500 ℃ exhibits a maximum value of tensile shear strength of 34.7 MPa.展开更多
Along with development of China＇s popular education, the embodiment of humanistic education is the natural and inevitable requirement of higher education after its transition from elite to popular education to ensure...Along with development of China＇s popular education, the embodiment of humanistic education is the natural and inevitable requirement of higher education after its transition from elite to popular education to ensure a good quality and a higher level. English teaching is indispensable due to the uniqueness of Chinese language and culture, and our open policy. College English teaching has become an extremely important platform, different from most other countries, to train talents. And to train talents is not only to train for the English language speakers or to be just certain technicians. This article will, from aspects of teaching philosophy, theory and mode, give a preliminary probe into the reasons why humanistic education should show itself up in all segments of college English teaching and how to show up. And it is expected to use the little to get the big.展开更多
A1 and N were introduced into copper substrate using plasma immersion ion implantation （PIII） in order to enhance its hardness and oxidation resistance. The dosage of N ion is 5 × 1016 cm-2, and range of dosage...A1 and N were introduced into copper substrate using plasma immersion ion implantation （PIII） in order to enhance its hardness and oxidation resistance. The dosage of N ion is 5 × 1016 cm-2, and range of dosage of A1 ion is 5× 1016-2× 1017 cm-2. The oxidation tests indicate that the copper samples after undergoing PIII possess higher oxidation resistance. The degree of oxidation resistance is found to vary with implantation dosage of AI ion. The antibacterial tests also reveal that the plasma implanted copper specimens have excellent antibacterial resistance against Staphylococcus aureus, which are similar to pure copper.展开更多
AIM:To evaluate the accuracy of axial length(AL)measurements obtained from immersion B-scan ultrasonography(immersion B-scan)for intraocular lens(IOL)power calculation in patients with high myopia and cataracts.METHOD...AIM:To evaluate the accuracy of axial length(AL)measurements obtained from immersion B-scan ultrasonography(immersion B-scan)for intraocular lens(IOL)power calculation in patients with high myopia and cataracts.METHODS:Immersion B-scan,contact A-scan ultrasonography(contact A-scan),and the IOLMaster were used to preoperatively measure the AL in 102 eyes from 102 patients who underwent phacoemulsification and IOL implantation.Patients were divided into two groups according to the AL:one containing patients with22 mm≤AL【26 mm(group A)and the other containing patients with AL≥26 mm(group B).The mean error(ME)was calculated from the difference between the AL measurement methods predicted refractive error and the actual postoperative refractive error.RESULTS:Ingroup A,ALs measured byimmersion Bscan(23.48±1.15)didn’t differ significantly from those measured by the IOLMaster(23.52±1.17)or from those by contact A-scan(23.38±1.20).In the same group,the standard deviation(SD)of the mean error(ME)of immersion B-scan(-0.090±0.397 D)didn’t differ significantly from those of IOLMaster(-0.095±0.411 D)and contact A-scan(-0.099±0.425 D).In group B,ALs measured by immersion B-scan(27.97±2.21 mm)didn’t differ significantly from those of the IOLMaster(27.86±2.18 mm),but longer than those measured by Contact A-scan(27.75±2.23 mm,P=0.009).In the same group,the standard deviation(SD)of the mean error(ME)of immersion B-scan(-0.635±0.157 D)didn’t differ significantly from those of the IOLMaster(-0.679±0.359 D),but differed significantly from those of contact A-scan(-0.953±1.713 D,P=0.028).CONCLUSION:ImmersionB-scanexhibitsmeasurement accuracy comparable to that of the IOLMaster,and is thus a good alternative in measuring AL in eyes with high myopia when the IOLMaster can’t be used,and it is more accurate than the contact A-scan.展开更多
A submanifold in a complex space form is called slant if it has constant Wirtinger angles. B. Y. Chen and Y. Tazawa proved that there do not exist minimal proper slant surfaces in CP2 and CH2. So it seems that the sla...A submanifold in a complex space form is called slant if it has constant Wirtinger angles. B. Y. Chen and Y. Tazawa proved that there do not exist minimal proper slant surfaces in CP2 and CH2. So it seems that the slant immersion has some interesting properties. The authors have great interest to consider slant immersions satisfying some additional conditions, such as unfull first normal bundles or Chen’s equality holding. They prove that there do not exist n-dimensional Kaehlerian slant immersions in CPn and CHn with unfull first normal bundles. Next, it is seen that every Kaehlerian slant submanifold satisfying an equality of Chen is minimal which is similar to that of Lagrangian immersions. But in contrast, it is shown that a large class of slant immersions do not exist thoroughly. Finally, they give an application of Chen’s inequality to general slant immersions in a complex projective space, which generalizes a result of Chen.展开更多
The research on plasma immersion ion implantation has been conducted for a little over ten years. Much is needed to investigate including processing technlogy, plasma sheath dynamics, interaction of plasma and surface...The research on plasma immersion ion implantation has been conducted for a little over ten years. Much is needed to investigate including processing technlogy, plasma sheath dynamics, interaction of plasma and surface, etc. Of the processing methods elavated temperature technique is usually used in PIII to produce a thick modified layer by means of the thermal diffusion. Meanwhile plasma ion heating is more recently developed by Ronghua Wei et al[1]. Therefore the temeperature is a critical parameter in plasma ion processing. In this paper we present the theoretical model and analysize the effect of imlantation voltage, plasma density, ion mass,etc on the temperature rise.展开更多
Silver has grown its attraction of the scientists in microelectronic field recently.Electrochemical deposition of silver onto copper substrates by immersion method has been one of the keen topics. In this study, ethan...Silver has grown its attraction of the scientists in microelectronic field recently.Electrochemical deposition of silver onto copper substrates by immersion method has been one of the keen topics. In this study, ethanol was used as the plating solution in which some chemicals were added. The silver deposits were characterized by a field emission scanning electron microscopy （FESEM）, an atom force microscope （AFM）, a transmission electron microscope （TEM） and a selected area electron diffraction （SAED）. It was found that silver immersion using ethanol-based bath has good coverage feature. The highlands of the copper substrate are coated by silver particles whose sizes are around 12 nm, but those sizes at low-lying lands are a little smaller.展开更多
Colonoscopy techniques combining or replacing air insufflation with water infusion are becoming increasinglypopular.They were originally designed to reduce colonic spasms,facilitate cecal intubation,and lower patient ...Colonoscopy techniques combining or replacing air insufflation with water infusion are becoming increasinglypopular.They were originally designed to reduce colonic spasms,facilitate cecal intubation,and lower patient discomfort and the need for sedation.These maneuvers straighten the rectosigmoid colon and enable the colonoscope to be inserted deeply without causing looping of the colon.Water-immersion colonoscopy minimizes colonic distension and improves visibility by introducing a small amount of water.In addition,since pain during colonoscopy indicates risk of bowel perforation and sedation masks this important warning,this method has the potential to be the favored insertion technique because it promotes patient safety without sedation.Recently,this water-immersion method has not only been used for colonoscope insertion,but has also been applied to therapy for sigmoid volvulus,removal of lesions,lower gastrointestinal bleeding,and therapeutic diagnosis of abnormal bowel morphology and irritable bowel syndrome.Although a larger sample size and prospective head-to-head-designed studies will be needed,this review focuses on the usefulness of waterimmersion colonoscopy for diagnostic and therapeutic applications.展开更多
Background: Wounded personnel who work at sea often encounter a plethora of difficulties. The most important of these difficulties is seawater immersion. Common medical dressings have little effect when the affected a...Background: Wounded personnel who work at sea often encounter a plethora of difficulties. The most important of these difficulties is seawater immersion. Common medical dressings have little effect when the affected area is immersed in seawater, and only rarely dressings have been reported for the treatment of seawater-immersed wounds. The objective of this study is to develop a new dressing which should be suitable to prevent the wound from seawater immersion and to promote the wound healing.Methods: Shark skin collagen(SSC) was purified via ethanol de-sugaring and de-pigmentation and adjusted for p H. A shark skin collagen sponge(SSCS) was prepared by freeze-drying. SSCS was attached to an anti-seawater immersion polyurethane(PU) film(SSCS+PU) to compose a new dressing. The biochemical properties of SSC and physicochemical properties of SSCS were assessed by standard methods. The effects of SSCS and SSCS+PU on the healing of seawaterimmersed wounds were studied using a seawater immersion rat model. For the detection of SSCS effects on seawaterimmersed wounds, 12 SD rats, with four wounds created in each rat, were divided into four groups: the 3 rd day group, 5 th day group, 7 th day group and 12 th day group. In each group, six wounds were treated with SSCS, three wounds treated with chitosan served as the positive control, and three wounds treated with gauze served as the negative control. For the detection of the SSCS+PU effects on seawater-immersed wounds, 36 SD rats were divided into three groups: the gauze(GZ)+PU group, chitosan(CS)+PU group and SSCS+PU group, with 12 rats in each group, and two wounds in each rat. The wound sizes were measured to calculate the healing rate, and histomorphology and the immunohistochemistry of the CD31 and TGF-β expression levels in the wounded tissues were measured by standard methods.Results: The results of Ultraviolet-visible(UV-vis) spectrum, Fourier-transform infrared(FTIR) spectrum, circular dichroism(CD) spectra, sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE), and amino acid composition analyses of SSC demonstrated that SSC is type I collagen. SSCS had a homogeneous porous structure of approximately 200μm, porosity rate of 83.57%±2.64%, water vapor transmission ratio(WVTR) of 4500 g/m2, tensile strength of 1.79±0.41 N/mm, and elongation at break of 4.52%±0.01%. SSCS had significant beneficial effects on seawater-immersed wound healing. On the 3 rd day, the healing rates in the GZ negative control, CS positive control and SSCS rats were 13.94%±5.50%, 29.40%±1.10% and 47.24%±8.40%, respectively. SSCS also enhanced TGF-in the initial stage of the healing period. The SSCS+PU dressing effectively protected woundsβ and CD31 expression from seawater immersion for at least 4 h, and accelerated re-epithelialization, vascularization and granulation formation of seawater-immersed wounds in the earlier stages of wound healing, and as well as significantly promoted wound healing. The SSCS+PU dressing also enhanced expression of TGF-n and gauze dressings.β and CD31. The effects of SSCS and SSCS+PU were superior to those of both the chitosaConclusion: SSCS has significant positive effects on the promotion of seawater-immersed wound healing, and a SSCS+PU dressing effectively prevents seawater immersion, and significantly promotes seawater-immersed wound healing.展开更多
Plasma immersion ion implantation (PIII), unrestricted by sight-light process, is considered a proper method for inner surface strengthening. Two-dimensional simulation oj inner surface PIII process of cylindrical bo...Plasma immersion ion implantation (PIII), unrestricted by sight-light process, is considered a proper method for inner surface strengthening. Two-dimensional simulation oj inner surface PIII process of cylindrical bores were carried out in this paper using cold plasma fluid model, and influence of the bore's dimension on impact energy, retained dose and uniformity of inner surface were investigated.展开更多
AIM： To compare the results of axial length （AL） biometry in cataract eyes by three methods： immersion B-ultrasound （IB） biometry, immersion A-ultrasound （IA） biometry and optical low coherence reflectometry. ...AIM： To compare the results of axial length （AL） biometry in cataract eyes by three methods： immersion B-ultrasound （IB） biometry, immersion A-ultrasound （IA） biometry and optical low coherence reflectometry. METHODS： In this prospective observational study of eyes with cataract AL measurements were performed using immersion ultrasound and optical low coherence reflectometry device. The results were evaluated using Bland-Altman analyses. The differences between both methods were assessed using the paired t-test, and its correlation was evaluated by Pearson coefficient. RESULTS： Eighty eyes of 80 patients （39 men and 41 women） for cataract surgery were included in the study. The values of AL could be got from all 80 eyes by IB and IA, the difference of AL measurements between IA and IB was of no statistical significance （P=0.97）; the mean difference in AL measurements was -0.031 mm （P=0.26; 95%CI, -0.09 to 0.02）; linear regression showed an excellent correlation （r=0.98, P〈0.0001）. Forty-five of eighty eyes with results of AL measurements, which can be obtained by three methods; the difference of AL measurements was of no statistical significance （IA vs IB, P=0.18; IA vs Lenstar, P=0.51; IB vs Lenstar, P=0.07）; linear regression showed an excellent correlation （IA vs IB, r=0.99; IA vs Lenstar, r=0.96; IB vs Lenstar, r=0.96）; Bland-Altman analysis also showed good agreement between the two methods [IA vs IB, 95% limits of agreement （LoA）, -0.36 to 0.28 mm; IA vs Lenstar, 95% LoA, -0.65 to 0.69 mm; IB vs Lenstar, 95% LoA, -0.55 to 0.68 mm]. CONCLUSION： Measurements with the optical low coherence reflectometry correlated well with IB and IA. In the eyes with serious refractive medium opacity, the measurements of AL could not be achieved or existed deviations when using optical low coherence reflectometry device. Under such circumstances, we should choose IA or IB as the optimization method to obtain measurements, in order to get much more accurate results.展开更多
The translation of brand names is a new branch in the field of translation along with the development of economy and trade between countries,which has its own characteristics.As the language and culture of English and...The translation of brand names is a new branch in the field of translation along with the development of economy and trade between countries,which has its own characteristics.As the language and culture of English and Chinese both differ from each other,this essay is explored to study the transliteration of brand names from English to Chinese so as to examine how meanings are embodied in the translation.展开更多
Electroless nickel/immersion gold (ENIG) technology is widely used as one of the surface final finish for electronics packaging substrate and printed circuit board (PCB), providing a protective, conductive and soldera...Electroless nickel/immersion gold (ENIG) technology is widely used as one of the surface final finish for electronics packaging substrate and printed circuit board (PCB), providing a protective, conductive and solderable surface. However, there is a solder joint interfacial brittle fracture (or solderability failure) of using the ENIG coating. The characteristics and the application of ENIG technology were narrated in this paper. The research progress on the solderability failure of ENIG was introduced. The mechanism of 'black pad' and the possible measure of eliminating or alleviating the 'black pad' were also introduced. The development direction and market prospects of ENIG were prospected.展开更多
Nanocomposite multilayer TiBN coatings were prepared on Si(100) and 9Cr18Mo substrates using TiBN composite cathode plasma immersion ion implantation and deposition technique(PIIID). Synthesis of TiBN composite cathod...Nanocomposite multilayer TiBN coatings were prepared on Si(100) and 9Cr18Mo substrates using TiBN composite cathode plasma immersion ion implantation and deposition technique(PIIID). Synthesis of TiBN composite cathodes was conducted by powder metallurgy technology and the content of hexagonal boron nitride(h-BN) was changed from 8% to 40%(mass fraction). The as-deposited coatings were characterized by energy dispersive spectrometer(EDS), grazing incidence X-ray diffraction(GIXRD), Fourier Transform Infrared Spectroscopy(FTIR) and high resolution transmission electron microcopy(HRTEM). EDS results show that the B content of the coatings was varied from 3.71% to 13.84%(molar fraction) when the composition of the h-BN in the composited cathodes was changed from 8 % to 40%(mass fraction). GIXRD results reveal that the TiBN coatings with a B content of 8% has the main diffraction peak of TiN(200),(220) and(311), and these peaks disappear when the B content is increased. FTIR analysis of the multilayer coatings showed the presence of h-BN in all coatings. TEM images reveal that all coatings have the characteristics of self-forming nanocomposite multilayers, where the nanocomposites are composed of face-centered cubic Ti N or h-BN nanocrystalline embedded in amorphous matrix. The tribological tests reveal that the Ti BN coatings exhibit a marked decrease of coefficient at room temperature(~0.25). The improved properties were found to be derived from the comprehensiveness of the self-forming multilayers structure and the h-BN solid lubrication effects in the coatings.展开更多
This paper reports the comparative evaluation of the corrosion behaviour of AZ31B magnesium alloy under immersion and potentiodynamic polarization test in NaCl solution at different chloride ion concentrations,pH valu...This paper reports the comparative evaluation of the corrosion behaviour of AZ31B magnesium alloy under immersion and potentiodynamic polarization test in NaCl solution at different chloride ion concentrations,pH value and exposure time.The specimens were exposed to immersion and polarization environments in order to evaluate their corrosion rates.Empirical relationship was established to predict the corrosion rate of AZ31B magnesium alloy.Three factors,five level,central composite rotatable design matrix was used to minimize the number of experimental conditions.Response surface methodology was used to develop the relationship.The developed relationship can be effectively used to predict the corrosion rate of AZ31B magnesium alloy at 95%confidence level for both the testing.This research work proves a better corrosion resistance of AZ31B magnesium alloy at the alkaline solution than the acidic and the neutral solutions,moreover,low corrosion rate was found at low concentrated solution and higher exposure time respectively.展开更多
基金the Strategic research and consulting project of Chinese Academy of Engineering(2023-HY-14).
文摘Background Physical entity interactions in mixed reality(MR)environments aim to harness human capabilities in manipulating physical objects,thereby enhancing virtual environment(VEs)functionality.In MR,a common strategy is to use virtual agents as substitutes for physical entities,balancing interaction efficiency with environmental immersion.However,the impact of virtual agent size and form on interaction performance remains unclear.Methods Two experiments were conducted to explore how virtual agent size and form affect interaction performance,immersion,and preference in MR environments.The first experiment assessed five virtual agent sizes(25%,50%,75%,100%,and 125%of physical size).The second experiment tested four types of frames(no frame,consistent frame,half frame,and surrounding frame)across all agent sizes.Participants,utilizing a head mounted display,performed tasks involving moving cups,typing words,and using a mouse.They completed questionnaires assessing aspects such as the virtual environment effects,interaction effects,collision concerns,and preferences.Results Results from the first experiment revealed that agents matching physical object size produced the best overall performance.The second experiment demonstrated that consistent framing notably enhances interaction accuracy and speed but reduces immersion.To balance efficiency and immersion,frameless agents matching physical object sizes were deemed optimal.Conclusions Virtual agents matching physical entity sizes enhance user experience and interaction performance.Conversely,familiar frames from 2D interfaces detrimentally affect interaction and immersion in virtual spaces.This study provides valuable insights for the future development of MR systems.
基金support from the Key Laboratory of Multiphase Flow Reaction and Separation Engineering of Shandong Province,China(Grant No.2021MFRSE-C01)the Natural Science Foundation of Gansu Province,China(No.22JR5RA269)Fujian Province Science Foundation for Youths,China(No.2020305069).
文摘The power density of electronic components grows continuously,and the subsequent heat accumulation and temperature increase inevitably affect electronic equipment’s stability,reliability and service life.Therefore,achieving efficient cooling in limited space has become a key problem in updating electronic devices with high performance and high integration.Two-phase immersion is a novel cooling method.The computational fluid dynamics(CFD)method is used to investigate the cooling performance of two-phase immersion cooling on high-power electronics.The two-dimensional CFD model is utilized by the volume of fluid(VOF)method and Reynolds StressModel.Lee’s model was employed to calculate the phase change rate.The heat transfer coefficient along the heatedwalls and the shear-lift force on bubbles are calculated.The simulation data are verified with the literature results.The cooling performance of different coolants has been studied.The results indicate that the boiling heat transfer coefficient can be enhanced by using a low boiling point coolant.The methanol is used as the cooling medium for further research.In addition,the mass flow rate and inlet temperature are investigated to assess the thermal performance of twophase immersion cooling.The average temperature of the high-power electronics is 80℃,and the temperature difference can be constrained to 8℃.Meanwhile,the convective heat transfer coefficient reaches 2740 W/(m2・℃)when the inlet temperature is 50℃,and the mass flow rate is 0.3 kg/s.In conclusion,the results demonstrated that two-phase immersion cooling has provided an effective method for the thermal management of high-power electronics.
文摘In this paper, we deal with isommetric immersions of globally null warped product manifolds into Lorentzian manifolds with constant curvature c in codimension k≥3. Under the assumptions that the globally null warped product manifold has no points with the same constant sectional curvature c as the Lorentzian ambient, we show that such isometric immersion splits into warped product of isometric immersions.
基金Projects (51274054,51375070,51271042) supported by the National Natural Science Foundation of ChinaProjects (2013M530913) supported by the China Postdoctoral Science Foundation
文摘A nickel-based coating was deposited on the pure Al substrate by immersion plating,and the Al/Cu bimetals were prepared by diffusion bonding in the temperature range of 450-550 ℃.The interce microstructure and fracture surface of Al/Cu joints were studied by scanning electron microscopy（SEM） and X-ray diffraction（XRD）.The mechanical properties of the Al/Cu bimetals were measured by tensile shear and microhardness tests.The results show that the Ni interiayer can effectively eliminate the formation of Al-Cu intermetallic compounds.The Al/Ni interface consists of the Al3Ni and Al3Ni2 phases,while it is Ni-Cu solid solution at the Ni/Cu interce.The tensile shear strength of the joints is improved by the addition of Ni interiayer.The joint with Ni interiayer annealed at 500 ℃ exhibits a maximum value of tensile shear strength of 34.7 MPa.
文摘Along with development of China＇s popular education, the embodiment of humanistic education is the natural and inevitable requirement of higher education after its transition from elite to popular education to ensure a good quality and a higher level. English teaching is indispensable due to the uniqueness of Chinese language and culture, and our open policy. College English teaching has become an extremely important platform, different from most other countries, to train talents. And to train talents is not only to train for the English language speakers or to be just certain technicians. This article will, from aspects of teaching philosophy, theory and mode, give a preliminary probe into the reasons why humanistic education should show itself up in all segments of college English teaching and how to show up. And it is expected to use the little to get the big.
基金Project(9231083) supported by Yunnan Aerospace Industry Corporation Contract Research,ChinaProject(9220061) supported by City University of Hong Kong Donation Research Grant,China
文摘A1 and N were introduced into copper substrate using plasma immersion ion implantation （PIII） in order to enhance its hardness and oxidation resistance. The dosage of N ion is 5 × 1016 cm-2, and range of dosage of A1 ion is 5× 1016-2× 1017 cm-2. The oxidation tests indicate that the copper samples after undergoing PIII possess higher oxidation resistance. The degree of oxidation resistance is found to vary with implantation dosage of AI ion. The antibacterial tests also reveal that the plasma implanted copper specimens have excellent antibacterial resistance against Staphylococcus aureus, which are similar to pure copper.
基金Supported by National Key Basic Research Program of China(973 Program,No.2013CB967000)National Natural Science Foundation of China(No.81271052)
文摘AIM:To evaluate the accuracy of axial length(AL)measurements obtained from immersion B-scan ultrasonography(immersion B-scan)for intraocular lens(IOL)power calculation in patients with high myopia and cataracts.METHODS:Immersion B-scan,contact A-scan ultrasonography(contact A-scan),and the IOLMaster were used to preoperatively measure the AL in 102 eyes from 102 patients who underwent phacoemulsification and IOL implantation.Patients were divided into two groups according to the AL:one containing patients with22 mm≤AL【26 mm(group A)and the other containing patients with AL≥26 mm(group B).The mean error(ME)was calculated from the difference between the AL measurement methods predicted refractive error and the actual postoperative refractive error.RESULTS:Ingroup A,ALs measured byimmersion Bscan(23.48±1.15)didn’t differ significantly from those measured by the IOLMaster(23.52±1.17)or from those by contact A-scan(23.38±1.20).In the same group,the standard deviation(SD)of the mean error(ME)of immersion B-scan(-0.090±0.397 D)didn’t differ significantly from those of IOLMaster(-0.095±0.411 D)and contact A-scan(-0.099±0.425 D).In group B,ALs measured by immersion B-scan(27.97±2.21 mm)didn’t differ significantly from those of the IOLMaster(27.86±2.18 mm),but longer than those measured by Contact A-scan(27.75±2.23 mm,P=0.009).In the same group,the standard deviation(SD)of the mean error(ME)of immersion B-scan(-0.635±0.157 D)didn’t differ significantly from those of the IOLMaster(-0.679±0.359 D),but differed significantly from those of contact A-scan(-0.953±1.713 D,P=0.028).CONCLUSION:ImmersionB-scanexhibitsmeasurement accuracy comparable to that of the IOLMaster,and is thus a good alternative in measuring AL in eyes with high myopia when the IOLMaster can’t be used,and it is more accurate than the contact A-scan.
基金This project is supported by the NSFC(10271041)Tianyuan Youth Foundation of Mathematics.
文摘A submanifold in a complex space form is called slant if it has constant Wirtinger angles. B. Y. Chen and Y. Tazawa proved that there do not exist minimal proper slant surfaces in CP2 and CH2. So it seems that the slant immersion has some interesting properties. The authors have great interest to consider slant immersions satisfying some additional conditions, such as unfull first normal bundles or Chen’s equality holding. They prove that there do not exist n-dimensional Kaehlerian slant immersions in CPn and CHn with unfull first normal bundles. Next, it is seen that every Kaehlerian slant submanifold satisfying an equality of Chen is minimal which is similar to that of Lagrangian immersions. But in contrast, it is shown that a large class of slant immersions do not exist thoroughly. Finally, they give an application of Chen’s inequality to general slant immersions in a complex projective space, which generalizes a result of Chen.
文摘The research on plasma immersion ion implantation has been conducted for a little over ten years. Much is needed to investigate including processing technlogy, plasma sheath dynamics, interaction of plasma and surface, etc. Of the processing methods elavated temperature technique is usually used in PIII to produce a thick modified layer by means of the thermal diffusion. Meanwhile plasma ion heating is more recently developed by Ronghua Wei et al[1]. Therefore the temeperature is a critical parameter in plasma ion processing. In this paper we present the theoretical model and analysize the effect of imlantation voltage, plasma density, ion mass,etc on the temperature rise.
基金Supported by the Key Project Foundation of Fujian Province (No. 200I011)
文摘Silver has grown its attraction of the scientists in microelectronic field recently.Electrochemical deposition of silver onto copper substrates by immersion method has been one of the keen topics. In this study, ethanol was used as the plating solution in which some chemicals were added. The silver deposits were characterized by a field emission scanning electron microscopy （FESEM）, an atom force microscope （AFM）, a transmission electron microscope （TEM） and a selected area electron diffraction （SAED）. It was found that silver immersion using ethanol-based bath has good coverage feature. The highlands of the copper substrate are coated by silver particles whose sizes are around 12 nm, but those sizes at low-lying lands are a little smaller.
文摘Colonoscopy techniques combining or replacing air insufflation with water infusion are becoming increasinglypopular.They were originally designed to reduce colonic spasms,facilitate cecal intubation,and lower patient discomfort and the need for sedation.These maneuvers straighten the rectosigmoid colon and enable the colonoscope to be inserted deeply without causing looping of the colon.Water-immersion colonoscopy minimizes colonic distension and improves visibility by introducing a small amount of water.In addition,since pain during colonoscopy indicates risk of bowel perforation and sedation masks this important warning,this method has the potential to be the favored insertion technique because it promotes patient safety without sedation.Recently,this water-immersion method has not only been used for colonoscope insertion,but has also been applied to therapy for sigmoid volvulus,removal of lesions,lower gastrointestinal bleeding,and therapeutic diagnosis of abnormal bowel morphology and irritable bowel syndrome.Although a larger sample size and prospective head-to-head-designed studies will be needed,this review focuses on the usefulness of waterimmersion colonoscopy for diagnostic and therapeutic applications.
基金supported by a Major Project of the Ministry of National Science and Technology of China(Grant No.2014ZX09J14103-09C).
文摘Background: Wounded personnel who work at sea often encounter a plethora of difficulties. The most important of these difficulties is seawater immersion. Common medical dressings have little effect when the affected area is immersed in seawater, and only rarely dressings have been reported for the treatment of seawater-immersed wounds. The objective of this study is to develop a new dressing which should be suitable to prevent the wound from seawater immersion and to promote the wound healing.Methods: Shark skin collagen(SSC) was purified via ethanol de-sugaring and de-pigmentation and adjusted for p H. A shark skin collagen sponge(SSCS) was prepared by freeze-drying. SSCS was attached to an anti-seawater immersion polyurethane(PU) film(SSCS+PU) to compose a new dressing. The biochemical properties of SSC and physicochemical properties of SSCS were assessed by standard methods. The effects of SSCS and SSCS+PU on the healing of seawaterimmersed wounds were studied using a seawater immersion rat model. For the detection of SSCS effects on seawaterimmersed wounds, 12 SD rats, with four wounds created in each rat, were divided into four groups: the 3 rd day group, 5 th day group, 7 th day group and 12 th day group. In each group, six wounds were treated with SSCS, three wounds treated with chitosan served as the positive control, and three wounds treated with gauze served as the negative control. For the detection of the SSCS+PU effects on seawater-immersed wounds, 36 SD rats were divided into three groups: the gauze(GZ)+PU group, chitosan(CS)+PU group and SSCS+PU group, with 12 rats in each group, and two wounds in each rat. The wound sizes were measured to calculate the healing rate, and histomorphology and the immunohistochemistry of the CD31 and TGF-β expression levels in the wounded tissues were measured by standard methods.Results: The results of Ultraviolet-visible(UV-vis) spectrum, Fourier-transform infrared(FTIR) spectrum, circular dichroism(CD) spectra, sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE), and amino acid composition analyses of SSC demonstrated that SSC is type I collagen. SSCS had a homogeneous porous structure of approximately 200μm, porosity rate of 83.57%±2.64%, water vapor transmission ratio(WVTR) of 4500 g/m2, tensile strength of 1.79±0.41 N/mm, and elongation at break of 4.52%±0.01%. SSCS had significant beneficial effects on seawater-immersed wound healing. On the 3 rd day, the healing rates in the GZ negative control, CS positive control and SSCS rats were 13.94%±5.50%, 29.40%±1.10% and 47.24%±8.40%, respectively. SSCS also enhanced TGF-in the initial stage of the healing period. The SSCS+PU dressing effectively protected woundsβ and CD31 expression from seawater immersion for at least 4 h, and accelerated re-epithelialization, vascularization and granulation formation of seawater-immersed wounds in the earlier stages of wound healing, and as well as significantly promoted wound healing. The SSCS+PU dressing also enhanced expression of TGF-n and gauze dressings.β and CD31. The effects of SSCS and SSCS+PU were superior to those of both the chitosaConclusion: SSCS has significant positive effects on the promotion of seawater-immersed wound healing, and a SSCS+PU dressing effectively prevents seawater immersion, and significantly promotes seawater-immersed wound healing.
文摘Plasma immersion ion implantation (PIII), unrestricted by sight-light process, is considered a proper method for inner surface strengthening. Two-dimensional simulation oj inner surface PIII process of cylindrical bores were carried out in this paper using cold plasma fluid model, and influence of the bore's dimension on impact energy, retained dose and uniformity of inner surface were investigated.
基金Supported by the Key Projects of the Bureau of Health,Tianjin(No.2015KR05)
文摘AIM： To compare the results of axial length （AL） biometry in cataract eyes by three methods： immersion B-ultrasound （IB） biometry, immersion A-ultrasound （IA） biometry and optical low coherence reflectometry. METHODS： In this prospective observational study of eyes with cataract AL measurements were performed using immersion ultrasound and optical low coherence reflectometry device. The results were evaluated using Bland-Altman analyses. The differences between both methods were assessed using the paired t-test, and its correlation was evaluated by Pearson coefficient. RESULTS： Eighty eyes of 80 patients （39 men and 41 women） for cataract surgery were included in the study. The values of AL could be got from all 80 eyes by IB and IA, the difference of AL measurements between IA and IB was of no statistical significance （P=0.97）; the mean difference in AL measurements was -0.031 mm （P=0.26; 95%CI, -0.09 to 0.02）; linear regression showed an excellent correlation （r=0.98, P〈0.0001）. Forty-five of eighty eyes with results of AL measurements, which can be obtained by three methods; the difference of AL measurements was of no statistical significance （IA vs IB, P=0.18; IA vs Lenstar, P=0.51; IB vs Lenstar, P=0.07）; linear regression showed an excellent correlation （IA vs IB, r=0.99; IA vs Lenstar, r=0.96; IB vs Lenstar, r=0.96）; Bland-Altman analysis also showed good agreement between the two methods [IA vs IB, 95% limits of agreement （LoA）, -0.36 to 0.28 mm; IA vs Lenstar, 95% LoA, -0.65 to 0.69 mm; IB vs Lenstar, 95% LoA, -0.55 to 0.68 mm]. CONCLUSION： Measurements with the optical low coherence reflectometry correlated well with IB and IA. In the eyes with serious refractive medium opacity, the measurements of AL could not be achieved or existed deviations when using optical low coherence reflectometry device. Under such circumstances, we should choose IA or IB as the optimization method to obtain measurements, in order to get much more accurate results.
文摘The translation of brand names is a new branch in the field of translation along with the development of economy and trade between countries,which has its own characteristics.As the language and culture of English and Chinese both differ from each other,this essay is explored to study the transliteration of brand names from English to Chinese so as to examine how meanings are embodied in the translation.
基金Project supported by the Specialized Research Fund for the Doctoral Programof Higher Education (20030213007)the Heilongjiang Province Natural Science Foundation (E0325)
文摘Electroless nickel/immersion gold (ENIG) technology is widely used as one of the surface final finish for electronics packaging substrate and printed circuit board (PCB), providing a protective, conductive and solderable surface. However, there is a solder joint interfacial brittle fracture (or solderability failure) of using the ENIG coating. The characteristics and the application of ENIG technology were narrated in this paper. The research progress on the solderability failure of ENIG was introduced. The mechanism of 'black pad' and the possible measure of eliminating or alleviating the 'black pad' were also introduced. The development direction and market prospects of ENIG were prospected.
基金Projects(21573054,21327002,51401201)supported by the National Natural Science Foundation of ChinaProject(U1537214)supported by the Joint Funds Key Project of the National Natural Science Foundation of ChinaProject(51535003)supported by the State Key Program of National Natural Science of China
文摘Nanocomposite multilayer TiBN coatings were prepared on Si(100) and 9Cr18Mo substrates using TiBN composite cathode plasma immersion ion implantation and deposition technique(PIIID). Synthesis of TiBN composite cathodes was conducted by powder metallurgy technology and the content of hexagonal boron nitride(h-BN) was changed from 8% to 40%(mass fraction). The as-deposited coatings were characterized by energy dispersive spectrometer(EDS), grazing incidence X-ray diffraction(GIXRD), Fourier Transform Infrared Spectroscopy(FTIR) and high resolution transmission electron microcopy(HRTEM). EDS results show that the B content of the coatings was varied from 3.71% to 13.84%(molar fraction) when the composition of the h-BN in the composited cathodes was changed from 8 % to 40%(mass fraction). GIXRD results reveal that the TiBN coatings with a B content of 8% has the main diffraction peak of TiN(200),(220) and(311), and these peaks disappear when the B content is increased. FTIR analysis of the multilayer coatings showed the presence of h-BN in all coatings. TEM images reveal that all coatings have the characteristics of self-forming nanocomposite multilayers, where the nanocomposites are composed of face-centered cubic Ti N or h-BN nanocrystalline embedded in amorphous matrix. The tribological tests reveal that the Ti BN coatings exhibit a marked decrease of coefficient at room temperature(~0.25). The improved properties were found to be derived from the comprehensiveness of the self-forming multilayers structure and the h-BN solid lubrication effects in the coatings.
文摘This paper reports the comparative evaluation of the corrosion behaviour of AZ31B magnesium alloy under immersion and potentiodynamic polarization test in NaCl solution at different chloride ion concentrations,pH value and exposure time.The specimens were exposed to immersion and polarization environments in order to evaluate their corrosion rates.Empirical relationship was established to predict the corrosion rate of AZ31B magnesium alloy.Three factors,five level,central composite rotatable design matrix was used to minimize the number of experimental conditions.Response surface methodology was used to develop the relationship.The developed relationship can be effectively used to predict the corrosion rate of AZ31B magnesium alloy at 95%confidence level for both the testing.This research work proves a better corrosion resistance of AZ31B magnesium alloy at the alkaline solution than the acidic and the neutral solutions,moreover,low corrosion rate was found at low concentrated solution and higher exposure time respectively.
