This study used near-infrared(NIR)spectroscopy to predict mechanical properties of wood.NIR spectra were collected in wavelengths 900–1700 nm,and spectra averaged by radial and tangential surface spectra were used to...This study used near-infrared(NIR)spectroscopy to predict mechanical properties of wood.NIR spectra were collected in wavelengths 900–1700 nm,and spectra averaged by radial and tangential surface spectra were used to establish a partial least square(PLS)model based on correlation local embedding(CLE).Mongolian oak(Quercus mongolica Fisch.ex Ledeb.)was used to test the eff ectiveness of the model.The cross-validation method was used to verify the robustness of the CLE–PLS model.Ninety samples were tested as the calibration set and forty-fi ve as the validation set.The results show that the prediction coeffi cient of determination(R2 p)is 0.80 for MOR,and 0.78 for MOE.The ratio of performance to deviation is 2.23 for MOR and 2.15 for MOE.展开更多
Neurological complications after cardiac surgery, rang- ing from permanent stroke to transient dysfunction, repre- sent a key issue in the management of geriatric patients. Many patients aged 70 or more have history o...Neurological complications after cardiac surgery, rang- ing from permanent stroke to transient dysfunction, repre- sent a key issue in the management of geriatric patients. Many patients aged 70 or more have history of neurological dysfunctions, which increases the risk of complications and sequelae, Severe neurologic diseases, such as strokes, occur in up to 6% of patients undergoing cardiac surgery. Therefore, in the setting of fragile patients, prevention is more important than treatment. There are several intraop- erative mechanisms of neurological injury, such as embo- lism, inflammation, intraoperative anemia,展开更多
Organic semiconductor materials have shown unique advantages in the development of optoelectronic devices due to their ease of preparation,low cost,lightweight,and flexibility.In this work,we explored the application ...Organic semiconductor materials have shown unique advantages in the development of optoelectronic devices due to their ease of preparation,low cost,lightweight,and flexibility.In this work,we explored the application of the organic semiconductor Y6-1O single crystal in photodetection devices.Firstly,Y6-1O single crystal material was prepared on a silicon substrate using solution droplet casting method.The optical properties of Y6-1O material were characterized by polarized optical microscopy,fluorescence spectroscopy,etc.,confirming its highly single crystalline performance and emission properties in the near-infrared region.Phototransistors based on Y6-1O materials with different thicknesses were then fabricated and tested.It was found that the devices exhibited good visible to near-infrared photoresponse,with the maximum photoresponse in the near-infrared region at 785 nm.The photocurrent on/off ratio reaches 10^(2),and photoresponsivity reaches 16 mA/W.It was also found that the spectral response of the device could be regulated by gate voltage as well as the material thickness,providing important conditions for optimizing the performance of near-infrared photodetectors.This study not only demonstrates the excellent performance of organic phototransistors based on Y6-1O single crystal material in near-infrared detection but also provides new ideas and directions for the future development of infrared detectors.展开更多
BACKGROUND: Near-infrared spectroscopy(NIRS) non-invasively monitors muscle tissue oxygen saturation(St O2). It may provide a continuous noninvasive measurement to identify occult hypoperfusion, guide resuscitation, a...BACKGROUND: Near-infrared spectroscopy(NIRS) non-invasively monitors muscle tissue oxygen saturation(St O2). It may provide a continuous noninvasive measurement to identify occult hypoperfusion, guide resuscitation, and predict the development of multiple organ dysfunction(MOD) after severe trauma. We evaluated the correlation between initial St O2 and the development of MOD in multi-trauma patients.METHODS: Patients presenting to our urban, academic, Level I Trauma Center/Emergency Department and meeting standardized trauma-team activation criteria were enrolled in this prospective trial. NIRS monitoring was initiated immediately on arrival with collection of St O2 at the thenar eminence and continued up to 24 hours for those admitted to the Trauma Intensive Care Unit(TICU). Standardized resuscitation laboratory measures and clinical evaluation tools were collected. The primary outcome was the association between initial St O2 and the development of MOD within the f irst 24 hours based on a MOD score of 6 or greater. Descriptive statistical analyses were performed; numeric means, multivariate regression and rank sum comparisons were utilized. Clinicians were blinded from the StO 2 values.RESULTS: Over a 14 month period, 78 patients were enrolled. Mean age was 40.9 years(SD 18.2), 84.4% were male, 76.9% had a blunt trauma mechanism and mean injury severity score(ISS) was 18.5(SD 12.9). Of the 78 patients, 26(33.3%) developed MOD within the first 24 hours. The MOD patients had mean initial St O2 values of 53.3(SD 10.3), signifi cantly lower than those of nonMOD patients 61.1(SD 10.0); P=0.002. The mean ISS among MOD patients was 29.9(SD 11.5), significantly higher than that of non-MODS patients, 12.1(SD 9.1)(P<0.0001). The mean shock index(SI) among MOD patients was 0.92(SD 0.28), also signifi cantly higher than that of non-MODS patients, 0.73(SD 0.19)(P=0.0007). Lactate values were not signifi cantly different between groups.CONCLUSION: Non-invasive, continuous St O2 near-infrared spectroscopy values during initial trauma resuscitation correlate with the later development of multiple organ dysfunction in this patient population.展开更多
When ultra-thin graphite intercalation compounds（GICs） are deposited on the SiO2/Si substrate, it is found that their colors are dependent on the thickness of GIC flakes. The sample colors of ultrathin GIC flakes ca...When ultra-thin graphite intercalation compounds（GICs） are deposited on the SiO2/Si substrate, it is found that their colors are dependent on the thickness of GIC flakes. The sample colors of ultrathin GIC flakes can no longer provide qualitative information on the stage index. Here, multi-wavelength Raman spectroscopy is thus applied to study the doping inhomogeneity and staging of ultra-thin GICs by FeCl3 intercalation. The G band intensity of stage-1 GIC flakes is strongly enhanced by 532-nm laser excitation, while that of stage-2 and stage-3 flakes exhibits strong intensity enhancement for 785-nm laser excitation. The near-infrared lasers are suggested to probe the doping inhomogeneity and staging of ultra-thin GIC flakes.展开更多
In sub nanometer carbon nanotubes,water exhibits unique dynamic characteristics,and in the high-frequency region of the infrared spectrum,where the stretching vibrations of the internal oxygen-hydrogen(O-H)bonds are c...In sub nanometer carbon nanotubes,water exhibits unique dynamic characteristics,and in the high-frequency region of the infrared spectrum,where the stretching vibrations of the internal oxygen-hydrogen(O-H)bonds are closely related to the hydrogen bonds(H-bonds)network between water molecules.Therefore,it is crucial to analyze the relationship between these two aspects.In this paper,the infrared spectrum and motion characteristics of the stretching vibrations of the O-H bonds in one-dimensional confined water(1DCW)and bulk water(BW)in(6,6)single-walled carbon nanotubes(SWNT)are studied by molecular dynamics simulations.The results show that the stretching vibrations of the two O-H bonds in 1DCW exhibit different frequencies in the infrared spectrum,while the O-H bonds in BW display two identical main frequency peaks.Further analysis using the spring oscillator model reveals that the difference in the stretching amplitude of the O-H bonds is the main factor causing the change in vibration frequency,where an increase in stretching amplitude leads to a decrease in spring stiffness and,consequently,a lower vibration frequency.A more in-depth study found that the interaction of H-bonds between water molecules is the fundamental cause of the increased stretching amplitude and decreased vibration frequency of the O-H bonds.Finally,by analyzing the motion trajectory of the H atoms,the dynamic differences between 1DCW and BW are clearly revealed.These findings provide a new perspective for understanding the behavior of water molecules at the nanoscale and are of significant importance in advancing the development of infrared spectroscopy detection technology.展开更多
All-solid-state lithium batteries(ASSLBs)are strongly considered as the next-generation energy storage devices for their high energy density and intrinsic safety.The solid-solid contact between lithium metal and solid...All-solid-state lithium batteries(ASSLBs)are strongly considered as the next-generation energy storage devices for their high energy density and intrinsic safety.The solid-solid contact between lithium metal and solid electrolyte plays a vital role in the performance of working ASSLBs,which is challenging to investigate quantitatively by experimental approach.This work proposed a quantitative model based on the finite element method for electrochemical impedance spectroscopy simulation of different solid-solid contact states in ASSLBs.With the assistance of an equivalent circuit model and distribution of relaxation times,it is discovered that as the number of voids and the sharpness of cracks increase,the contact resistance Rcgrows and ultimately dominates the battery impedance.Through accurate fitting,inverse proportional relations between contact resistance Rcand(1-porosity)as well as crack angle was disclosed.This contribution affords a fresh insight into clarifying solid-solid contact states in ASSLBs.展开更多
Nitrogen(N)monitoring is essential in nurseries to ensure the production of high-quality seedlings.Nearinfrared spectroscopy(NIRS)is an instantaneous,nondestructive method to monitor N.Spectral data such as NIRS can a...Nitrogen(N)monitoring is essential in nurseries to ensure the production of high-quality seedlings.Nearinfrared spectroscopy(NIRS)is an instantaneous,nondestructive method to monitor N.Spectral data such as NIRS can also provide the basis for developing a new vegetation spectral index(VSI).Here,we evaluated whether NIRS combined with statistical modeling can accurately detect early variations in N concentration in leaves of young plants of Annona emargiaata and developed a new VSI for this task.Plants were grown in a hydroponics system with 0,2.75,5.5or 11 mM N for 45 days.Then we measured gas exchange,chlorophylla fluorescence,and pigments in leaves;analyzed complete leaf nutrients,and recorded spectral data for leaves at 966 to 1685 nm using NIRS.With a statistical learning approach,the dimensionality of the spectral data was reduced,then models were generated using two classes(N deficiency,N)or four classes(0,2.75,5.5,11 mM N).The best combination of techniques for dimensionality reduction and classification,respectively,was stepwise regression(PROC STEPDISC)and linear discriminant function.It was possible to detect N deficiency in seedlings leaves with 100%precision,and the four N concentrations with93.55%accuracy before photosynthetic damage to the plant occurred.Thereby,NIRS combined with statistical modeling of multidimensional data is effective for detecting N variations in seedlings leaves of A.emarginata.展开更多
A new facile method for preparing water-soluble near-infrared （NIR）-emitting PbS quantum dots （QDs） is proposed by using N-acetyl-L-cysteine （NAC, a derivate of L-cysteine） as its stabilizer. The influence of th...A new facile method for preparing water-soluble near-infrared （NIR）-emitting PbS quantum dots （QDs） is proposed by using N-acetyl-L-cysteine （NAC, a derivate of L-cysteine） as its stabilizer. The influence of the precursor Pb/S molar ratio, the Pb/NAC molar ratio, and the pH of original solution on optical properties is explored. Results show that aqueous PbS QDs with strong NIR fluorescence can be prepared and their photoluminescence emission peaks can be tuned from 895 nm to 970 nm. Studies indicate that such aqueous QDs have a potential application in biomedical imaging, especially in noninvasive in vivo fluorescence imaging. In addition, the resulting PbS QDs are further characterized by a transmission electron microscopy and X-ray diffraction analysis.展开更多
In Ga As is an important bandgap-variable ternary semiconductor which has wide applications in electronics and optoelectronics. In this work, single-crystal In Ga As nanowires were synthesized by a chemical vapor depo...In Ga As is an important bandgap-variable ternary semiconductor which has wide applications in electronics and optoelectronics. In this work, single-crystal In Ga As nanowires were synthesized by a chemical vapor deposition method.Photoluminescence measurements indicate the In Ga As nanowires have strong light emission in near-infrared region. For the first time, photodetector based on as-grown In Ga As nanowires was also constructed. It shows good light response over a broad spectral range in infrared region with responsivity of 6.5×10~3 AW^(-1) and external quantum efficiency of 5.04×10~5%. This photodetector may have potential applications in integrated optoelectronic devices and systems.展开更多
A transfer learning system was designed to predict Xylosma racemosum compression strength.Near-infrared(NIR)spectral data for Acer mono and its compression strength values were used to resolve the weak generalization ...A transfer learning system was designed to predict Xylosma racemosum compression strength.Near-infrared(NIR)spectral data for Acer mono and its compression strength values were used to resolve the weak generalization problem caused by using a X.racemosum dataset alone.Transfer component analysis and principal component analysis are domain adaption and feature extraction processes to enable the use of A.mono NIR spectral data to design the transfer learning system.A five-layer neural network relevant to the X.racemosum dataset,was fine-tuned using the A.mono dataset.There were 109 A.mono samples used as the source dataset and 79 X.racemosum samples as the target dataset.When the ratio of the training set to the test set was 1:9,the correlation coeffi cient was 0.88,and mean square error was 8.84.The results show that NIR spectral data of hardwood species are related.Predicting the mechanical strength of hardwood species using multi-species NIR spectral datasets will improve the generalization ability of the model and increase accuracy.展开更多
Sub-ppmv level detection of hydrogen sulphide(H2 S) using a 1.578-μm distributed feedback tunable diode laser combining with wavelength modulation spectroscopy and second harmonic detection scheme is reported. A home...Sub-ppmv level detection of hydrogen sulphide(H2 S) using a 1.578-μm distributed feedback tunable diode laser combining with wavelength modulation spectroscopy and second harmonic detection scheme is reported. A home-developed novel compact dense-pattern multipass gas cell with an effective optical path length of 29.37 m is used to improve sensitivity and reduce sample volume. Detection parameters are optimized, including modulation frequency and amplitude. The analysis of Allan variance shows that a minimum detectable concentration 60 ppbv is obtained with a lock-in time constant of 10 ms, and a detection limit of 13 ppbv can be achieved by average in 300 s. The demonstrated H2 S sensor has a strong penitential application in natural gas process for regulating and controlling H2 S concentration.展开更多
This paper reviews the recent progress in the synthesis of near-infrared(NIR) lead chalcogenide(PbX;PbX = PbS,PbSe, PbTe) quantum dots(QDs) and their applications in NIR QDs based light emitting diodes(NIR-QLEDs). It ...This paper reviews the recent progress in the synthesis of near-infrared(NIR) lead chalcogenide(PbX;PbX = PbS,PbSe, PbTe) quantum dots(QDs) and their applications in NIR QDs based light emitting diodes(NIR-QLEDs). It summarizes the strategies of how to synthesize high efficiency PbX QDs and how to realize high performance Pb X based NIR-QLEDs.展开更多
The population ratio between the excited states of rubidium in the electrodeless discharge rubidium vapour lamp is calculated according to the near-infrared spectra in the region of 780-1550 nm. By using a 1529 nm las...The population ratio between the excited states of rubidium in the electrodeless discharge rubidium vapour lamp is calculated according to the near-infrared spectra in the region of 780-1550 nm. By using a 1529 nm laser, we measure the density of natural rubidium atoms at the 5P3/2 level. The populations of different excited states are then clarified.展开更多
We report on the successful fabrication of highly branched Cu S nanocrystals by laser-induced photochemical reaction.Surprisingly, the single-crystalline nature with preferential alignment of the（107） orientation ca...We report on the successful fabrication of highly branched Cu S nanocrystals by laser-induced photochemical reaction.Surprisingly, the single-crystalline nature with preferential alignment of the（107） orientation can be well improved during the moderate growth process. The branch length drastically increases from about 5 nm to 6 μm with an increase of photochemical reaction time（0-40 min）. The absorption spectra of as-prepared Cu S nanodendrites show that localized surface plasmon resonance（LSPR） peaks can be modulated from about 1037 nm to 1700 nm with an increase of branch length. Our results have a promising potential for photodynamic therapy and biological imaging application.展开更多
The 52%energy of the solar radiation is contributed by near-infrared radiation(NIR,780-2500 nm).Therefore,the material design for the energy-saving smart window,which can effectively shield NIR and has acceptable visi...The 52%energy of the solar radiation is contributed by near-infrared radiation(NIR,780-2500 nm).Therefore,the material design for the energy-saving smart window,which can effectively shield NIR and has acceptable visible transmittance,is vital to save the energy consumed on the temperature control system.It is important to find a non-toxic stable material with excellent NIR-shielding ability and acceptable visible transmittance.The systematic first-principles study on Li_(x)Sn_(y)WO_(3)(x=0,0.33,0.66,and y=0,0.33)exhibits that the chemical stability is a positive correlation with the doping concentration.After doping,the Fermi-energy upshifts into the conduction band,and the material shows metal-like characteristics.Therefore,these structures Li_(x)Sn_(y)WO_(3)(except the structure with x=0.33 and y=0)show pronounced improvement of NIR shielding ability.Our results indicate that when x=0 and y=0.33,the material exhibits the strongest NIR-shielding ability,satisfying chemical stability,wide NIR-shielding range(780-2500 nm),and acceptable visible transmittance.This work provides a good choice for experimental study on NIR shielding material for the energy-saving window.展开更多
In this paper,we propose a near-infrared p-type β-FeSi2/n-type 4H-SiC heterojunction photodetector with semiconducting silicide（β-FeSi2） as the active region for the first time.The optoelectronic characteristics o...In this paper,we propose a near-infrared p-type β-FeSi2/n-type 4H-SiC heterojunction photodetector with semiconducting silicide（β-FeSi2） as the active region for the first time.The optoelectronic characteristics of the photodetector are simulated using a commercial simulator at room temperature.The results show that the photodetector has a good rectifying character and a good response to near-infrared light.Interface states should be minimized to obtain a lower reverse leakage current.The response spectrum of the β-FeSi2/4H-SiC detector,which consists of a p-type β-FeSi2 absorption layer with a doping concentration of 1×1015cm-3 and a thickness of 2.5 μm,has a peak of 755 mA/W at 1.42 μm.The illumination of the SiC side obtains a higher responsivity than that of the β-FeSi2 side.The results illustrate that the β-FeSi2/4H-SiC heterojunction can be used as a near-infrared photodetector compatible with near-infrared optically-activated SiC-based power switching devices.展开更多
Direct absorption spectra of the 2v3 band of methane （CH4） from 6038 to 6050 cm 1 were studied at different low temperatures using a newly developed cryogenic cell in combination with a distributed feedback （DFB） ...Direct absorption spectra of the 2v3 band of methane （CH4） from 6038 to 6050 cm 1 were studied at different low temperatures using a newly developed cryogenic cell in combination with a distributed feedback （DFB） diode laser. The cryogenic cell can operate at any stabilized temperature ranging from room temperature down to 100 K with temperature fluctuation less than =t=1 K within 1 hour. In the present work, the CH4 spectra in the range of 6038-6050 cm-1 were recorded at 296, 266, 248, 223, 198, and 176 K. The lower state energy Ett and the rotational assignment of the angular momentum J were determined by a ＂2-low-temperature spectra method＂ using the spectra recorded at 198 and 176 K. The results were compared with the data from the GOSAT and the recently reported results from Campargue and co-workers using two spectra measured at room temperature and 81 K. We demonstrated that the use of a 2-low-temperature spectra method permits one to complete the Ett and J values missed in the previous studies.展开更多
A scheme to enhance near-infrared band absorption of a Si nanoparticle by placing the Si nanoparticle into a designed gold nanostructure is proposed. Three-dimensional （3D） finite-difference time-domain simulations ...A scheme to enhance near-infrared band absorption of a Si nanoparticle by placing the Si nanoparticle into a designed gold nanostructure is proposed. Three-dimensional （3D） finite-difference time-domain simulations are employed to calcu- late the absorption spectrum of the Si nanostructure and maximize it by generating alternate designs. The results show that in the near-infrared region over 700 nm, the absorption of a pure Si nanoparticle is very low, but when the same nanoparticle is placed within an optimally designed gold nanostructure, its absorption cross section can be enhanced by more than two orders of magnitude in the near-infrared band.展开更多
Polarization manipulation of light is of great importance because it could promote development of wireless communications,biosensing,and polarization imaging.In order to use natural light more efficiently,it is highly...Polarization manipulation of light is of great importance because it could promote development of wireless communications,biosensing,and polarization imaging.In order to use natural light more efficiently,it is highly demanded to design and fabricate high performance asymmetric polarization converters which could covert the natural light to one particular linearly polarized light with high efficiency.Traditionally,polarizers could be achieved by controllers with crystals and polymers exhibiting birefringence.However,the polarizers are bulky in size and the theoretical conversion efficiency of the polarizers is limited to 0.5 with unpolarized light incidence.In this paper,we propose a polarization converter which could preserve high transmission for one linearly polarized light and convert the orthogonal linearly polarized light to its cross-polarized with high transmittance based on a multi-layer chiral metasurface.Theoretical results show that normally incident y-polarized light preserves high transmittance for the wavelength range from 685 nm to 800 nm while the orthogonal normally incident x-polarized light is efficiently converted to the y-polarized light with high transmittance from 725 nm to 748 nm.Accordingly,for unpolarized light incidence,transmittance larger than 0.5 has been successfully achieved in a broadband wavelength range from 712 nm to 773 nm with a maximum transmittance of 0.58 at 732 nm.展开更多
基金financially supported by the China State Forestry Administration“948”projects(2015-4-52)Fundamental Research Funds for the Central Universities(2572017DB05)Heilongjiang Natural Science Foundation(C2017005)。
文摘This study used near-infrared(NIR)spectroscopy to predict mechanical properties of wood.NIR spectra were collected in wavelengths 900–1700 nm,and spectra averaged by radial and tangential surface spectra were used to establish a partial least square(PLS)model based on correlation local embedding(CLE).Mongolian oak(Quercus mongolica Fisch.ex Ledeb.)was used to test the eff ectiveness of the model.The cross-validation method was used to verify the robustness of the CLE–PLS model.Ninety samples were tested as the calibration set and forty-fi ve as the validation set.The results show that the prediction coeffi cient of determination(R2 p)is 0.80 for MOR,and 0.78 for MOE.The ratio of performance to deviation is 2.23 for MOR and 2.15 for MOE.
文摘Neurological complications after cardiac surgery, rang- ing from permanent stroke to transient dysfunction, repre- sent a key issue in the management of geriatric patients. Many patients aged 70 or more have history of neurological dysfunctions, which increases the risk of complications and sequelae, Severe neurologic diseases, such as strokes, occur in up to 6% of patients undergoing cardiac surgery. Therefore, in the setting of fragile patients, prevention is more important than treatment. There are several intraop- erative mechanisms of neurological injury, such as embo- lism, inflammation, intraoperative anemia,
基金Supported by the National Key Research and Development Program of China(2021YFB2012601)National Natural Science Foundation of China(12204109)+1 种基金Science and Technology Innovation Plan of Shanghai Science and Technology Commission(21JC1400200)Higher Education Indus⁃try Support Program of Gansu Province(2022CYZC-06)。
文摘Organic semiconductor materials have shown unique advantages in the development of optoelectronic devices due to their ease of preparation,low cost,lightweight,and flexibility.In this work,we explored the application of the organic semiconductor Y6-1O single crystal in photodetection devices.Firstly,Y6-1O single crystal material was prepared on a silicon substrate using solution droplet casting method.The optical properties of Y6-1O material were characterized by polarized optical microscopy,fluorescence spectroscopy,etc.,confirming its highly single crystalline performance and emission properties in the near-infrared region.Phototransistors based on Y6-1O materials with different thicknesses were then fabricated and tested.It was found that the devices exhibited good visible to near-infrared photoresponse,with the maximum photoresponse in the near-infrared region at 785 nm.The photocurrent on/off ratio reaches 10^(2),and photoresponsivity reaches 16 mA/W.It was also found that the spectral response of the device could be regulated by gate voltage as well as the material thickness,providing important conditions for optimizing the performance of near-infrared photodetectors.This study not only demonstrates the excellent performance of organic phototransistors based on Y6-1O single crystal material in near-infrared detection but also provides new ideas and directions for the future development of infrared detectors.
文摘BACKGROUND: Near-infrared spectroscopy(NIRS) non-invasively monitors muscle tissue oxygen saturation(St O2). It may provide a continuous noninvasive measurement to identify occult hypoperfusion, guide resuscitation, and predict the development of multiple organ dysfunction(MOD) after severe trauma. We evaluated the correlation between initial St O2 and the development of MOD in multi-trauma patients.METHODS: Patients presenting to our urban, academic, Level I Trauma Center/Emergency Department and meeting standardized trauma-team activation criteria were enrolled in this prospective trial. NIRS monitoring was initiated immediately on arrival with collection of St O2 at the thenar eminence and continued up to 24 hours for those admitted to the Trauma Intensive Care Unit(TICU). Standardized resuscitation laboratory measures and clinical evaluation tools were collected. The primary outcome was the association between initial St O2 and the development of MOD within the f irst 24 hours based on a MOD score of 6 or greater. Descriptive statistical analyses were performed; numeric means, multivariate regression and rank sum comparisons were utilized. Clinicians were blinded from the StO 2 values.RESULTS: Over a 14 month period, 78 patients were enrolled. Mean age was 40.9 years(SD 18.2), 84.4% were male, 76.9% had a blunt trauma mechanism and mean injury severity score(ISS) was 18.5(SD 12.9). Of the 78 patients, 26(33.3%) developed MOD within the first 24 hours. The MOD patients had mean initial St O2 values of 53.3(SD 10.3), signifi cantly lower than those of nonMOD patients 61.1(SD 10.0); P=0.002. The mean ISS among MOD patients was 29.9(SD 11.5), significantly higher than that of non-MODS patients, 12.1(SD 9.1)(P<0.0001). The mean shock index(SI) among MOD patients was 0.92(SD 0.28), also signifi cantly higher than that of non-MODS patients, 0.73(SD 0.19)(P=0.0007). Lactate values were not signifi cantly different between groups.CONCLUSION: Non-invasive, continuous St O2 near-infrared spectroscopy values during initial trauma resuscitation correlate with the later development of multiple organ dysfunction in this patient population.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11225421,11474277,and 11434010)
文摘When ultra-thin graphite intercalation compounds（GICs） are deposited on the SiO2/Si substrate, it is found that their colors are dependent on the thickness of GIC flakes. The sample colors of ultrathin GIC flakes can no longer provide qualitative information on the stage index. Here, multi-wavelength Raman spectroscopy is thus applied to study the doping inhomogeneity and staging of ultra-thin GICs by FeCl3 intercalation. The G band intensity of stage-1 GIC flakes is strongly enhanced by 532-nm laser excitation, while that of stage-2 and stage-3 flakes exhibits strong intensity enhancement for 785-nm laser excitation. The near-infrared lasers are suggested to probe the doping inhomogeneity and staging of ultra-thin GIC flakes.
基金Supported by the Natural Science Foundation of China(51705326,52075339)。
文摘In sub nanometer carbon nanotubes,water exhibits unique dynamic characteristics,and in the high-frequency region of the infrared spectrum,where the stretching vibrations of the internal oxygen-hydrogen(O-H)bonds are closely related to the hydrogen bonds(H-bonds)network between water molecules.Therefore,it is crucial to analyze the relationship between these two aspects.In this paper,the infrared spectrum and motion characteristics of the stretching vibrations of the O-H bonds in one-dimensional confined water(1DCW)and bulk water(BW)in(6,6)single-walled carbon nanotubes(SWNT)are studied by molecular dynamics simulations.The results show that the stretching vibrations of the two O-H bonds in 1DCW exhibit different frequencies in the infrared spectrum,while the O-H bonds in BW display two identical main frequency peaks.Further analysis using the spring oscillator model reveals that the difference in the stretching amplitude of the O-H bonds is the main factor causing the change in vibration frequency,where an increase in stretching amplitude leads to a decrease in spring stiffness and,consequently,a lower vibration frequency.A more in-depth study found that the interaction of H-bonds between water molecules is the fundamental cause of the increased stretching amplitude and decreased vibration frequency of the O-H bonds.Finally,by analyzing the motion trajectory of the H atoms,the dynamic differences between 1DCW and BW are clearly revealed.These findings provide a new perspective for understanding the behavior of water molecules at the nanoscale and are of significant importance in advancing the development of infrared spectroscopy detection technology.
基金supported by the Beijing Natural Science Foundation(Z200011,L233004)the National Key Research and Development Program(2021YFB2500300)+3 种基金the National Natural Science Foundation of China(52394170,52394171,22109011,22393900,and 22108151)the Tsinghua-Jiangyin Innovation Special Fund(TJISF)(2022JYTH0101)the S&T Program of Hebei(22344402D)the Tsinghua University Initiative Scientific Research Program.
文摘All-solid-state lithium batteries(ASSLBs)are strongly considered as the next-generation energy storage devices for their high energy density and intrinsic safety.The solid-solid contact between lithium metal and solid electrolyte plays a vital role in the performance of working ASSLBs,which is challenging to investigate quantitatively by experimental approach.This work proposed a quantitative model based on the finite element method for electrochemical impedance spectroscopy simulation of different solid-solid contact states in ASSLBs.With the assistance of an equivalent circuit model and distribution of relaxation times,it is discovered that as the number of voids and the sharpness of cracks increase,the contact resistance Rcgrows and ultimately dominates the battery impedance.Through accurate fitting,inverse proportional relations between contact resistance Rcand(1-porosity)as well as crack angle was disclosed.This contribution affords a fresh insight into clarifying solid-solid contact states in ASSLBs.
基金a scholarship from Capes(Coordena??o de Aperfei?oamento de Pessoal de Nível Superior)-Brazil(Award number:001)for the first author。
文摘Nitrogen(N)monitoring is essential in nurseries to ensure the production of high-quality seedlings.Nearinfrared spectroscopy(NIRS)is an instantaneous,nondestructive method to monitor N.Spectral data such as NIRS can also provide the basis for developing a new vegetation spectral index(VSI).Here,we evaluated whether NIRS combined with statistical modeling can accurately detect early variations in N concentration in leaves of young plants of Annona emargiaata and developed a new VSI for this task.Plants were grown in a hydroponics system with 0,2.75,5.5or 11 mM N for 45 days.Then we measured gas exchange,chlorophylla fluorescence,and pigments in leaves;analyzed complete leaf nutrients,and recorded spectral data for leaves at 966 to 1685 nm using NIRS.With a statistical learning approach,the dimensionality of the spectral data was reduced,then models were generated using two classes(N deficiency,N)or four classes(0,2.75,5.5,11 mM N).The best combination of techniques for dimensionality reduction and classification,respectively,was stepwise regression(PROC STEPDISC)and linear discriminant function.It was possible to detect N deficiency in seedlings leaves with 100%precision,and the four N concentrations with93.55%accuracy before photosynthetic damage to the plant occurred.Thereby,NIRS combined with statistical modeling of multidimensional data is effective for detecting N variations in seedlings leaves of A.emarginata.
基金Supported by the National Natural Science Foundation of China (30800257,30700799)the Scien-tific Research Starting Foundation for Introduced Talented Persons of China Pharmaceutical University~~
文摘A new facile method for preparing water-soluble near-infrared （NIR）-emitting PbS quantum dots （QDs） is proposed by using N-acetyl-L-cysteine （NAC, a derivate of L-cysteine） as its stabilizer. The influence of the precursor Pb/S molar ratio, the Pb/NAC molar ratio, and the pH of original solution on optical properties is explored. Results show that aqueous PbS QDs with strong NIR fluorescence can be prepared and their photoluminescence emission peaks can be tuned from 895 nm to 970 nm. Studies indicate that such aqueous QDs have a potential application in biomedical imaging, especially in noninvasive in vivo fluorescence imaging. In addition, the resulting PbS QDs are further characterized by a transmission electron microscopy and X-ray diffraction analysis.
基金the NSF of China(Nos.61574054,61505051,11374092,11204073,61474040,and51302077)the National Basic Research Program of China(No.2012CB932703)+2 种基金the Hunan province science and technology plan(No.2014FJ2001,2014GK3015,and 2014TT1004)the Hunan Provincial Natural Science Foundation of China(No.2015JJ3049)the Aid program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province
文摘In Ga As is an important bandgap-variable ternary semiconductor which has wide applications in electronics and optoelectronics. In this work, single-crystal In Ga As nanowires were synthesized by a chemical vapor deposition method.Photoluminescence measurements indicate the In Ga As nanowires have strong light emission in near-infrared region. For the first time, photodetector based on as-grown In Ga As nanowires was also constructed. It shows good light response over a broad spectral range in infrared region with responsivity of 6.5×10~3 AW^(-1) and external quantum efficiency of 5.04×10~5%. This photodetector may have potential applications in integrated optoelectronic devices and systems.
基金fully funded by the Program of National Natural Science Foundation of China(CN)(31700643)Fundamental Research Funds for the Central Universities(2572015AB24)。
文摘A transfer learning system was designed to predict Xylosma racemosum compression strength.Near-infrared(NIR)spectral data for Acer mono and its compression strength values were used to resolve the weak generalization problem caused by using a X.racemosum dataset alone.Transfer component analysis and principal component analysis are domain adaption and feature extraction processes to enable the use of A.mono NIR spectral data to design the transfer learning system.A five-layer neural network relevant to the X.racemosum dataset,was fine-tuned using the A.mono dataset.There were 109 A.mono samples used as the source dataset and 79 X.racemosum samples as the target dataset.When the ratio of the training set to the test set was 1:9,the correlation coeffi cient was 0.88,and mean square error was 8.84.The results show that NIR spectral data of hardwood species are related.Predicting the mechanical strength of hardwood species using multi-species NIR spectral datasets will improve the generalization ability of the model and increase accuracy.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2016YFC0303900 and 2017YFC0209700)
文摘Sub-ppmv level detection of hydrogen sulphide(H2 S) using a 1.578-μm distributed feedback tunable diode laser combining with wavelength modulation spectroscopy and second harmonic detection scheme is reported. A home-developed novel compact dense-pattern multipass gas cell with an effective optical path length of 29.37 m is used to improve sensitivity and reduce sample volume. Detection parameters are optimized, including modulation frequency and amplitude. The analysis of Allan variance shows that a minimum detectable concentration 60 ppbv is obtained with a lock-in time constant of 10 ms, and a detection limit of 13 ppbv can be achieved by average in 300 s. The demonstrated H2 S sensor has a strong penitential application in natural gas process for regulating and controlling H2 S concentration.
基金Project supported by the National Key Research and Development Program,China(Grant Nos.2016YFB0401702 and 2017YFE0120400)the National Natural Science Foundation of China(Grant Nos.61875082 and 61405089)+6 种基金the Guangdong University Key Laboratory for Advanced Quantum Dot Displays and Lighting,China(Grant No.2017KSYS007)the Natural Science Foundation of Guangdong,China(Grant No.2017B030306010)the Guangdong Province’s 2018–2019 Key R&D Program:Environmentally Friendly Quantum Dots Luminescent Materials,China(Grant No.2019B010924001)the Shenzhen Innovation Project,China(Grant Nos.JCYJ20160301113356947 and JSGG20170823160757004)the Shenzhen Peacock Team Project,China(Grant No.KQTD2016030111203005)the Shenzhen Key Laboratory for Advanced Quantum Dot Displays and Lighting,China(Grant No.ZDSYS201707281632549)the Tianjin New Materials Science and Technology Key Project,China(Grant No.16ZXCLGX00040)
文摘This paper reviews the recent progress in the synthesis of near-infrared(NIR) lead chalcogenide(PbX;PbX = PbS,PbSe, PbTe) quantum dots(QDs) and their applications in NIR QDs based light emitting diodes(NIR-QLEDs). It summarizes the strategies of how to synthesize high efficiency PbX QDs and how to realize high performance Pb X based NIR-QLEDs.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10874009 and 11074011)
文摘The population ratio between the excited states of rubidium in the electrodeless discharge rubidium vapour lamp is calculated according to the near-infrared spectra in the region of 780-1550 nm. By using a 1529 nm laser, we measure the density of natural rubidium atoms at the 5P3/2 level. The populations of different excited states are then clarified.
基金Project supported by National Natural Science Foundation of China(Grant Nos.11575102,11105085,11405098,and 11375108)the Fundamental Research Funds of Shandong University,China(Grant No.2015JC007)
文摘We report on the successful fabrication of highly branched Cu S nanocrystals by laser-induced photochemical reaction.Surprisingly, the single-crystalline nature with preferential alignment of the（107） orientation can be well improved during the moderate growth process. The branch length drastically increases from about 5 nm to 6 μm with an increase of photochemical reaction time（0-40 min）. The absorption spectra of as-prepared Cu S nanodendrites show that localized surface plasmon resonance（LSPR） peaks can be modulated from about 1037 nm to 1700 nm with an increase of branch length. Our results have a promising potential for photodynamic therapy and biological imaging application.
文摘The 52%energy of the solar radiation is contributed by near-infrared radiation(NIR,780-2500 nm).Therefore,the material design for the energy-saving smart window,which can effectively shield NIR and has acceptable visible transmittance,is vital to save the energy consumed on the temperature control system.It is important to find a non-toxic stable material with excellent NIR-shielding ability and acceptable visible transmittance.The systematic first-principles study on Li_(x)Sn_(y)WO_(3)(x=0,0.33,0.66,and y=0,0.33)exhibits that the chemical stability is a positive correlation with the doping concentration.After doping,the Fermi-energy upshifts into the conduction band,and the material shows metal-like characteristics.Therefore,these structures Li_(x)Sn_(y)WO_(3)(except the structure with x=0.33 and y=0)show pronounced improvement of NIR shielding ability.Our results indicate that when x=0 and y=0.33,the material exhibits the strongest NIR-shielding ability,satisfying chemical stability,wide NIR-shielding range(780-2500 nm),and acceptable visible transmittance.This work provides a good choice for experimental study on NIR shielding material for the energy-saving window.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60876050 and 51177134)
文摘In this paper,we propose a near-infrared p-type β-FeSi2/n-type 4H-SiC heterojunction photodetector with semiconducting silicide（β-FeSi2） as the active region for the first time.The optoelectronic characteristics of the photodetector are simulated using a commercial simulator at room temperature.The results show that the photodetector has a good rectifying character and a good response to near-infrared light.Interface states should be minimized to obtain a lower reverse leakage current.The response spectrum of the β-FeSi2/4H-SiC detector,which consists of a p-type β-FeSi2 absorption layer with a doping concentration of 1×1015cm-3 and a thickness of 2.5 μm,has a peak of 755 mA/W at 1.42 μm.The illumination of the SiC side obtains a higher responsivity than that of the β-FeSi2 side.The results illustrate that the β-FeSi2/4H-SiC heterojunction can be used as a near-infrared photodetector compatible with near-infrared optically-activated SiC-based power switching devices.
基金Project supported by the National Natural Science Foundation of China(Grant No.41175036)
文摘Direct absorption spectra of the 2v3 band of methane （CH4） from 6038 to 6050 cm 1 were studied at different low temperatures using a newly developed cryogenic cell in combination with a distributed feedback （DFB） diode laser. The cryogenic cell can operate at any stabilized temperature ranging from room temperature down to 100 K with temperature fluctuation less than =t=1 K within 1 hour. In the present work, the CH4 spectra in the range of 6038-6050 cm-1 were recorded at 296, 266, 248, 223, 198, and 176 K. The lower state energy Ett and the rotational assignment of the angular momentum J were determined by a ＂2-low-temperature spectra method＂ using the spectra recorded at 198 and 176 K. The results were compared with the data from the GOSAT and the recently reported results from Campargue and co-workers using two spectra measured at room temperature and 81 K. We demonstrated that the use of a 2-low-temperature spectra method permits one to complete the Ett and J values missed in the previous studies.
基金Project supported by the National Key Basic Research and Development Program of China(Grant No.2013CB632704)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.Y1 V2013L11)
文摘A scheme to enhance near-infrared band absorption of a Si nanoparticle by placing the Si nanoparticle into a designed gold nanostructure is proposed. Three-dimensional （3D） finite-difference time-domain simulations are employed to calcu- late the absorption spectrum of the Si nanostructure and maximize it by generating alternate designs. The results show that in the near-infrared region over 700 nm, the absorption of a pure Si nanoparticle is very low, but when the same nanoparticle is placed within an optimally designed gold nanostructure, its absorption cross section can be enhanced by more than two orders of magnitude in the near-infrared band.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62075173 and 12274478)the National Key Research and Development Program of China(Grant Nos.2021YFB2800302 and 2021YFB2800604).
文摘Polarization manipulation of light is of great importance because it could promote development of wireless communications,biosensing,and polarization imaging.In order to use natural light more efficiently,it is highly demanded to design and fabricate high performance asymmetric polarization converters which could covert the natural light to one particular linearly polarized light with high efficiency.Traditionally,polarizers could be achieved by controllers with crystals and polymers exhibiting birefringence.However,the polarizers are bulky in size and the theoretical conversion efficiency of the polarizers is limited to 0.5 with unpolarized light incidence.In this paper,we propose a polarization converter which could preserve high transmission for one linearly polarized light and convert the orthogonal linearly polarized light to its cross-polarized with high transmittance based on a multi-layer chiral metasurface.Theoretical results show that normally incident y-polarized light preserves high transmittance for the wavelength range from 685 nm to 800 nm while the orthogonal normally incident x-polarized light is efficiently converted to the y-polarized light with high transmittance from 725 nm to 748 nm.Accordingly,for unpolarized light incidence,transmittance larger than 0.5 has been successfully achieved in a broadband wavelength range from 712 nm to 773 nm with a maximum transmittance of 0.58 at 732 nm.
