Simulation of the Ecosystem Productivity Responses to Aerosol Diffuse Radiation Fertilization Effects over the Pan-Arctic during 2001–19

The pan-Arctic is confronted with air pollution transported from lower latitudes.Observations have shown that aerosols help increase plant photosynthesis through the diffuse radiation fertilization effects(DRFEs).While such DRFEs have been explored at low to middle latitudes,the aerosol impacts on pan-Arctic ecosystems and the contributions by anthropogenic and natural emission sources remain less quantified.Here,we perform regional simulations at 0.2o×0.2ousing a well-validated vegetation model(Yale Interactive terrestrial Biosphere,YIBs)in combination with multi-source of observations to quantify the impacts of aerosol DRFEs on the net primary productivity(NPP)in the pan-Arctic during 2001-19.Results show that aerosol DRFEs increase pan-Arctic NPP by 2.19 Pg C(12.8%)yr^(-1)under clear-sky conditions,in which natural and anthropogenic sources contribute to 8.9% and 3.9%,respectively.Under all-sky conditions,such DRFEs are largely dampened by cloud to only 0.26 Pg C(1.24%)yr^(-1),with contributions of 0.65% by natural and 0.59% by anthropogenic species.Natural aerosols cause a positive NPP trend of 0.022% yr^(-1)following the increased fire activities in the pan-Arctic.In contrast,anthropogenic aerosols induce a negative trend of-0.01% yr^(-1)due to reduced emissions from the middle latitudes.Such trends in aerosol DRFEs show a turning point in the year of 2007 with more positive NPP trends by natural aerosols but negative NPP trends by anthropogenic aerosols thereafter.Though affected by modeling uncertainties,this study suggests a likely increasing impact of aerosols on terrestrial ecosystems in the pan-Arctic under global warming.

Total Ionizing Dose Radiation Effects on MOS Transistors with Different Layouts

Both nMOS and pMOS transistors with two-edged and multi-finger layouts are fabricated in a standard commercial 0.6μm CMOS/bulk process to study their total ionizing dose （TID） radiation effects. The leakage current, threshold voltage shift, and transconductance of the devices are monitored before and after T-ray irradiation. Different device bias conditions are used during irradiation. The experiment results show that TID radiation effects on nMOS devices are very sensitive to their layout structures. The impact of the layout on TID effects on pMOS devices is slight and can be neglected.

Effects of Si Ion Implantation on the Total-Dose Radiation Properties of SIMOX SOI Materials

To improve the total-dose radiation hardness,silicon-on-insulator （SOI） wafers fabricated by the separation-by-implanted-oxygen （SIMOX） method are modified by Si ion implantation into the buried oxide with a post anneal. The ID- VG characteristics can be tested with the pseudo-MOSFET method before and after radiation. The results show that a proper Si-ion-implantation method can enhance the total-dose radiation tolerance of the materials.

Machine learning-based analyses for total ionizing dose effects in bipolar junction transistors

Machine learning methods have proven to be powerful in various research fields.In this paper,we show that research on radiation effects could benefit from such methods and present a machine learning-based scientific discovery approach.The total ionizing dose(TID)effects usually cause gain degradation of bipolar junction transistors(BJTs),leading to functional failures of bipolar integrated circuits.Currently,many experiments of TID effects on BJTs have been conducted at different laboratories worldwide,producing a large amount of experimental data which provides a wealth of information.However,it is difficult to utilize these data effectively.In this study,we proposed a new artificial neural network(ANN)approach to analyze the experimental data of TID effects on BJTs An ANN model was built and trained using data collected from different experiments.The results indicate that the proposed ANN model has advantages in capturing nonlinear correlations and predicting the data.The trained ANN model suggests that the TID hardness of a BJT tends to increase with base current I.A possible cause for this finding was analyzed and confirmed through irradiation experiments.

AGGLOMERATION AND RADIATION EFFECT OF THE PULL OF URBANIZATION

In order to explore the train of thought for China’s urbanizing development and coordinated rural economic development, and to find good ways of solving rural problems through urbanization, this paper absorbs the push-and-pull forces theory and the systematic dynamic theory in the traditional population migration theories, views urbanization as a dynamic system, makes research on the push-and-pull mechanism of urbanization. The pulling power of urbanization is analyzed according to two aspects, the agglomeration effect and the radiation effect of cities. The agglomeration effect provides continuous propelling force for urbanization, and the radiation effect further accelerates the urbanization process by pushing forward the development of rural economy. Of course, the slow development of urbanization can result in the hindrance to rural economic development.

Radiation-hardened property of single-walled carbon nanotube film-based field-effect transistors under low-energy proton irradiation

Strong C-C bonds,nanoscale cross-section and low atomic number make single-walled carbon nanotubes(SWCNTs)a potential candidate material for integrated circuits(ICs)applied in outer space.However,very little work combines the simulation calculations with the electrical measurements of SWCNT field-effect transistors(FETs),which limits further understanding on the mechanisms of radiation effects.Here,SWCNT film-based FETs were fabricated to explore the total ionizing dose(TID)and displacement damage effect on the electrical performance under low-energy proton irradiation with different fluences up to 1×1015 p/cm2.Large negative shift of the threshold voltage and obvious decrease of the on-state current verified the TID effect caused in the oxide layer.The stability of the subthreshold swing and the off-state current reveals that the displacement damage caused in the CNT layer is not serious,which proves that the CNT film is radiation-hardened.Specially,according to the simulation,we found the displacement damage caused by protons is different in the source/drain contact area and channel area,leading to varying degrees of change for the contact resistance and sheet resistance.Having analyzed the simulation results and electrical measurements,we explained the low-energy proton irradiation mechanism of the CNT FETs,which is essential for the construction of radiation-hardened CNT film-based ICs for aircrafts.

Effects of Electromagnetic Radiation on Autophagy and its Regulation

With the ever increasing application of electronic technology, our exposure to artificial electromagnetic energy is also rapidly increasing. Electromagnetic radiation （EMR） is the fourth largest source of pollution, after air, water, and noise.

Study of total ionizing dose radiation effects on enclosed gate transistors in a commercial CMOS technology

This paper studies the total ionizing dose radiation effects on MOS （metal-oxide-semiconductor） transistors with normal and enclosed gate layout in a standard commercial CMOS （compensate MOS） bulk process. The leakage current, threshold voltage shift, and transconductance of the devices were monitored before and after γ-ray irradiation. The parameters of the devices with different layout under different bias condition during irradiation at different total dose are investigated. The results show that the enclosed layout not only effectively eliminates the leakage but also improves the performance of threshold voltage and transconductance for NMOS （n-type channel MOS） transistors. The experimental results also indicate that analogue bias during irradiation is the worst case for enclosed gate NMOS. There is no evident different behaviour observed between normal PMOS （p-type channel MOS） transistors and enclosed gate PMOS transistors.

Effect of bias condition on heavy ion radiation in bipolar junction transistors

The characteristic degradations in a silicon NPN bipolar junction transistor （BJT） of 3DG142 type are examined under irradiation with 40-MeV chlorine （C1） ions under forward, grounded, and reverse bias conditions, respectively. Different electrical parameters are in-situ measured during the exposure under each bias condition. From the experimental data, a larger variation of base current （IB） is observed after irradiation at a given value of base-emitter voJtage （VBE）, while the collector current is slightly affected by irradiation at a given VBE. The gain degradation is affected mostly by the behaviour of the base current. From the experimental data, the variation of current gain in the case of forward bias is much smaller than that in the other conditions. Moreover, for 3DG142 BJT, the current gain degradation in the case of reverse bias is more severe than that in the grounded case at low fluence, while at high fluence, the gain degradation in the reverse bias case becomes smaller than that in the grounded case.

Analysis of Heat Transport in a Powell-Eyring Fluid with Radiation and Joule Heating Effects via a Similarity Transformation

Heat transfer in an Eyring-Powell fluid that conducts electricity and flows past an exponentially growing sheet is considered.As the sheet is stretched in the x direction,the flow develops in the region with y>0.The problem is tackled through a set of partial differential equations accounting for Magnetohydrodynamics(MHD),radiation and Joule heating effects,which are converted into a set of equivalent ordinary differential equations through a similarity transformation.The converted problem is solved in MATLAB in the framework a fourth order accurate integration scheme.It is found that the thermal relaxation period is inversely proportional to the thickness of the thermal boundary layer,whereas the Eckert-number displays the opposite trend.As this characteristic number grows,the temperature within the channel increases.

Radiation dose effects on the morphological development of M_(1) generation pea(Pisum sativum)

We irradiated pea seeds with neutrons from a ^(252)Cf source and studied the radiation dose effects on various morphological development parameters during the growth of M_(1) generation peas.We found that in the dose range of 0.51-9.27 Gy,with the increase in neutron-absorbed dose,the morphological development parameters of M_(1) generation peas at the initial seedling stage showed an obvious trend with three fluctuations.With the development of pea,this trend gradually weakened.Further analysis and verification showed that the main trend in the M_(1) generation of pea seeds was an inhibitory effect induced by neutron irradiation and there was a good linear correlation between the inhibitory effect and neutron absorption dose We successfully demonstrated the background removal of mutant plants and defined morphological developmen parameters for peas that match the overall development of plants.Our results will positively impact neutron mutation breeding and automatic agriculture.

Effect of Low Dose Radiation on Intracellular Calcium and Protein Kinase C in Lymphocytes

It is first reported in the present paper that whole-body irradiation (WBI) with low dose X-rays could increase intracellular calcium ions ([Ca2+]i) and stimulate protein kinase C (PKC) activity of mouse lymphocytes. Following WBI of male Kunming micc With 75 mGy X-rays at a dose rate of 12.5 mGy/min the mobilization of [Ca2+]i with Con A in CD4+ and CD8+ Cells in the thymus and spleen was potentiated and the amplitude of [Ca2+], mobilization in thymocytes in response to anti-CD3 monoclonal antibody increased with time from 4 to 24 h following low dose radiation. The PKC activity in the homogenate of spleen was markedly stimulated 12 h after WBl with 75 mGy, reaching its peak value at 24-48 h and coming down to lower than normal on day 7. However, the PKC activity in the separated T lymphocytes reached its peak value at 12 h and that in the B lymphocytes reached its peak value on day 4, both coming down to below control on day 7. The implications of this facilitation of signal transduction in T lymphocytes in the mechanism of immunoenhancement after low dose radiation were discussed

Proton radiation effect on GaAs/AlGaAs core–shell ensemble nanowires photo-detector

We demonstrate that the GaAs/AlGaAs nanowires（NWs） ensemble is fabricated into photo-detectors. Current–voltage（I–V） characteristics are measured on Ga As/Al Ga As core–shell ensemble NW photo-detectors at room-temperature before and after 1-MeV proton irradiation with fluences from 1.0 × 10^（13） cm^（-2） to 5.0 × 10^（14） cm^（-2）. The degradation of photocurrent suggests that the point defects induced by proton radiation could cause both carrier lifetime and carrier mobility to decrease synchronously. Comparing with a GaAs quantum well, the degradations of light and dark current for the irradiated NWs photo-detector indicate that NWs material is a preferable potential candidate for space applications.

Spectroscopic Properties and Effect of Radiation Trapping of a New Er^(3+)/Yb^(3+) Co-Doped Tellurite-Silicate Glasses

A new serials of Er^3＋/Yb^3＋ co-doped tellurite-silicate glasses were prepared by the technique of high-temperature mehing. The thermal stability, absorption spectra, emission spectra and upconversion spectra were measured and investigated. It is found that these kinds of glasses have good thermal stability, broad FWHM and large stimulated emission cross-section. The three upconversion emission at 525, 546, 658 nm, corresponding to the ^2H11/2→^4Ⅰ15/2, ^4S3/2→4^Ⅰ15/2 and ^F9/2→^4Ⅰ15/2 transitions of Dr^3＋ ions,

Effect of heavy ion irradiation on the interface traps of AlGaN/GaN high electron mobility transistors

AlGaN/GaN high electron mobility transistors(HEMTs)were irradiated with heavy ions at various fluences.After irradiation by 2.1 GeV^(181) Ta^(32+) ions,the electrical characteristics of the devices significantly decreased.The threshold voltage shifted positively by approximately 25%and the saturation currents decreased by approximately 14%.Defects were induced in the band gap and the interface between the gate and barrier acted as tunneling sites,which increased the gate current tunneling probability.According to the pulsed output characteristics,the amount of current collapse significantly increased and more surface state traps were introduced after heavy ion irradiation.The time constants of the induced surface traps were mainly less than 10μs.

Radiation effects on MOS and bipolar devices by 8 MeV protons,60 MeV Br ions and 1 MeV electrons

The radiation effects of the metal-oxide-semiconductor （MOS） and the bipolar devices are characterised using 8 MeV protons, 60 MeV Br ions and 1 MeV electrons. Key parameters are measured in-situ and compared for the devices. The ionising and nonionising energy losses of incident particles are calculated using the Geant4 and the stopping and range of ions in matter code. The results of the experiment and energy loss calculation for different particles show that different incident particles may give different contributions to MOS and bipolar devices. The irradiation particles, which cause a larger displacement dose within the same chip depth of bipolar devices at a given total dose, would generate more severe damage to the voltage parameters of the bipolar devices. On the contrary, the irradiation particles, which cause larger ionising damage in the gate oxide, would generate more severe damage to MOS devices. In this investigation, we attempt to analyse the sensitivity to radiation damage of the different parameter of the MOS and bipolar devices by comparing the irradiation experimental data and the calculated results using Geant4 and SRIM code.

Using Earth’s Moon as a Testbed for Quantifying the Effect of the Terrestrial Atmosphere

In the past, the planetary radiation balance served to quantify the atmospheric greenhouse effect by the difference between the globally averaged near-surface temperature of and the respective effective radiation temperature of the Earth without atmosphere of resulting in . Since such a “thought experiment” prohibits any rigorous assessment of its results, this study considered the Moon as a testbed for the Earth in the absence of its atmosphere. Since the angular velocity of Moon’s rotation is 27.4 times slower than that of the Earth, the forcing method, the force-restore method, and a multilayer-force-restore method, used in climate modeling during the past four decades, were alternatively applied to address the influence of the angular velocity in determining the Moon’s globally averaged skin (or slab) temperature, . The multilayer-force-restore method always provides?the highest values for , followed by the force-restore method and the forcing method, but the differences are marginal. Assuming a solar albedo of , a relative emissivity , and a solar constant of and applying the multilayer-force-restore method yielded and for the Moon. Using the same values for α, ε, and S, but assuming the Earth’s angular velocity for the Moon yielded and quantifying the effect of the terrestrial atmosphere by . A sensitivity study for a solar albedo of commonly assumed for the Earth in the absence of its atmosphere yielded , , and . This means that the atmospheric effect would be more than twice as large as the aforementioned difference of 33 K. To generalize the findings, twelve synodic months (i.e., 354 Earth days) and 365 Earth days, where , a Sun-zenith-distance dependent solar albedo, and the variation of the solar radiation in dependence of the actual orbit position and the tilt angle of the corresponding rotation axis to the ecliptic were considered. The case of Moon’s true angular velocity yielded and . Whereas Earth’s 27.4 times higher angular velocity yielded , and . In both cases, the effective radiation temperature is ,?because the computed global albedo is . Thus, the effective radiation temperature yields flawed results when used for quantifying the atmospheric greenhouse effect.

EFFECT OF TOTAL IRRADIATION DOSE ON MOSFETs/SOI

The MOSFETs are built on SIMOX material, the chide positive charge, interface state, threshold voltage and leakage current of MOSFETs/SOI after 60Co-rirradiation are measured with I-V technique. The results indicate that the accumulation rate of chide charge density is more than that of interface state density in dose range of 0-3×104Gy (Si), and the 'on' radiation bias is worst case for NMOSFET and PMOSFET.

Total Ionizing Dose Radiation Effects in the P-Type Polycrystalline Silicon Thin Film Transistors

The total ionizing dose radiation effects in the polycrystalline silicon thin film transistors are studied. Transfer characteristics, high-frequency capacitance-voltage curves and low-frequency noises (LFN) are measured before and after radiation. The experimental results show that threshold voltage and hole-field-effect mobility decrease, while sub-threshold swing and low-frequency noise increase with the increase of the total dose. The contributions of radiation induced interface states and oxide trapped charges to the shift of threshold voltage are also estimated. Furthermore, spatial distributions of oxide trapped charges before and after radiation are extracted based on the LFN measurements.

Radiation Effect of Neutrons in a Reactor on Polyurethane

The radiation effect of neutrons in a reactor on polyurethane was studied.The gases produced by irradiated samples were analyzed by gas chromatography,and the dynamic mechanical and compression properties of the samples were also studied.The positron annihilation lifetime of irradiated samples was measured at room temperature in vacuum.The experimental results indicate that gas chromatography is a powerful tool to quantitatively analyze the gas products from neutron-irradiated polyurethane and characterizes the chemical changes in the sample.And the changes in microstructure determined from the PAL correlate well with the measurements of the mechanical properties by dynamic mechanical analysis（DMA）.