Two-dimensional particle-in-cell modeling of blow-off impulse by X-ray irradiation

Space objects such as spacecraft or missiles may be exposed to intense X-rays in outer space,leading to severe damage.The reinforcement of these objects to reduce the damage caused by X-ray irradiation is a significant concern.The blow-off impulse(BOI)is a crucial physical quantity for investigating material damage induced by X-ray irradiation.However,the accurate calculation of BOI is challenging,particularly for large deformations of materials with complex configurations.In this study,we develop a novel two-dimensional particle-in-cell code,Xablation2D,to calculate BOIs under far-field X-ray irradiation.This significantly reduces the dependence of the numerical simulation on the grid shape.The reliability of this code is verified by simulation results from open-source codes,and the calculated BOIs are consistent with the experimental and analytical results.

Review on synergistic damage effect of irradiation and corrosion on reactor structural alloys

The synergistic damage effect of irradiation and corrosion of reactor structural materials has been a prominent research focus.This paper provides a comprehensive review of the synergistic effects on the third-and fourth-generation fission nuclear energy structural materials used in pressurized water reactors and molten salt reactors.The competitive mechanisms of multiple influencing factors,such as the irradiation dose,corrosion type,and environmental temperature,are summarized in this paper.Conceptual approaches are proposed to alleviate the synergistic damage caused by irradiation and corrosion,thereby promoting in-depth research in the future and solving this key challenge for the structural materials used in reactors.

Storage Stability in Reversion Mutation of a Rice Line Devoid of LOX-1, 2 Acquired by Ion Beam Irradiation

The effect of absence of lipoxygenase isoenzyme （LOX） on storage stability was investigated. Rice mutant 1297 without lipoxygenase isoenzyme-1 （LOX-1） or lipoxygenase isoenzyme-2 （LOX-2） generated by ion beam irradiation from Wanjian2090 and reversion mutant RM1297 with LOX-1 and LOX-2 were subjected to an accelerated-aging experiment. Shanyou63 （with LOX-1 and LOX-2 ） served as control. Results showed that the germination and dehydrogenase activity decreased while the electrical conductivity and free fatty acid content increased in all varieties with accelerated aging. In 1297 that lacked LOX-1 and 2, there were slight changes in germination, dehydrogenase activity, membrane permeability and free fatty acid content during the thirty-day accelerated-aging experiment. But in varieties with LOX-1 and LOX-2, significant changes were observed, suggesting that LOX-1, 2 might be a definite factor which influenced seed lifespan. This study also indicates that ion beam irradiation may be used as mutagen to generate mutant and reversion mutants for biological study and could become a new direction in ion beam application.

Effects of Corticosterone, cAMP, cGMP, Ca^(2+), and Protein Kinase C on Apoptosis of Mouse Thymocytes Induced by X-ray Irradiation

Objective To observe the effects of signal factors of corticosterone （CS）, cAMP, cGMP, Ca^2＋ and protein kinase C （PKC） on lymphocyte apoptosis in mouse thymus induced by X-rays of 4 Gy in vitro. Methods The DNA lyric rate for thymocytes was measured by fluomspectrophotometry. Results The DNA lyric rate for thymocytes 4-8 hours after irradiation with 2-8 Gy was significantly higher than that in the control （P〈0.01）. As compared with the control, the DNA lyric rate for thymocytes treated with 0.01 μnol/L CS （P〈0.01）, 50 ng/mL cAMP （P〈0.01）, 0.05-0.4 μg/mL ionomycin （Iono, P〈0.05 or P〈0.01） or 0.05-0.4 ng/mL phorbol myristate acetate （PMA, P〈0.05 or P〈0.01）, respectively, was significantly increased, while the rate for thymocytes treated with 50 ng/mL cGMP was not significantly increased. The DNA lyric rate for thymocytes treated with 0.01 μmol/L CS （P〈0.01）, 50 ng/mL cAMP （P〈0.01）, 0.2 and 0.4 μg/mL Iono （P〈0.05）, and 0.2 and 0.4 ng/mL PMA （P〈0.05） plus 4-Gy irradiation, respectively, was significantly higher than that treated with single 4-Gy irradiation, while the rate for thymocytes treated with 50 ng/mL cGMP plus 4-Gy irradiation was not increased. When both 0.4 I.tg/mL Iono and 0.4 ng/mL PMA acted on the thymocytes, the DNA lyric rate for thymocytes was significantly higher than that in the control （P〈0.01）, the DNA lytic rate for thymocytes treated with both 0.4 μg/mL Iono and 0.4 ng/mL PMA plus 4-Gy irradiation was significantly higher than that treated with single 4-Gy irradiation （P〈0.05）, but was Iono plus 4-Gy irradiation or 0.4 ng/mL PMA plus 4-Gy irradiation. can promote thymocyte apoptosis induced by larger dose X-rays. not significantly higher than that treated with 0.4 μg/mL Conclusion CS, cAMP, Ca^2＋, and PKC signal factors can promote thymocyte apoptosis induced by larger dose X-rays.

Determination of Timer Error and Evaluation of Its Effect on Dose for OB6, GammaBeam X200 and X-Ray Irradiators at the Secondary Standard Dosimetry Laboratory in Nigeria

Timer error as well as its convention is very important for dose accuracy during irradiation. This paper determines the timer error of irradiators at Secondary Standard Dosimetry Laboratory (SSDL) in Nigeria. The irradiators are Cs-137 OB6 irradiator and X-ray irradiators at the Protection level SSDL;and Co-60 irradiator at the Therapy Level SSDL. PTW UNIDOS electrometer and LS01 Ionization chamber were used at the Protection Level to obtain doses for both Cs-137 OB6 and X-ray irradiators while an IBA farmer type ionization chamber and an IBA DOSE 1 electrometer were used at the Protection Level SSDL. Single/multiple exposure method and graphical method were used in the determination of the timer error for the three irradiators. The timer error obtained for Cs-137 OB6 irradiator was 0.48 ± 0.01 s, the timer error for the X-ray irradiator was 0.09 ± 0.01 s while the timer error obtained for GammaBeam X200 was 1.21 ± 0.04 s. It was observed that the timer error is not affected by source to detector distance. It was also observed that the timer error of Co-60 Gamma X200 irradiator is increasing with the age of the machine. Source to detector distance and field size do not contribute towards the timer error of the irradiators. The timer error of the Co-60 Gamma X200 irradiator (the only irradiator among the irradiators with a pneumatic system) increases with the age of the irradiator.

Neutron irradiation influence on high-power thyristor device under fusion environment

Because of their economy and applicability,high-power thyristor devices are widely used in the power supply systems for large fusion devices.When high-dose neutrons produced by deuterium–tritium(D–T)fusion reactions are irradiated on a thyristor device for a long time,the electrical characteristics of the device change,which may eventually cause irreversible damage.In this study,with the thyristor switch of the commutation circuit in the quench protection system(QPS)of a fusion device as the study object,the relationship between the internal physical structure and external electrical parameters of the irradiated thyristor is established.Subsequently,a series of targeted thyristor physical simulations and neutron irradiation experiments are conducted to verify the accuracy of the theoretical analysis.In addition,the effect of irradiated thyristor electrical characteristic changes on the entire QPS is studied by accurate simulation,providing valuable guidelines for the maintenance and renovation of the QPS.

Demonstration of irradiation-resistant 4H-SiC based photoelectrochemical water splitting

4H silicon carbide(4H-SiC)has gained a great success in high-power electronics,owing to its advantages of wide bandgap,high breakdown electric field strength,high carrier mobility,and high thermal conductivity.Considering the high carrier mobility and high stability of 4H-SiC,4H-SiC has great potential in the field of photoelectrochemical(PEC)water splitting.In this work,we demonstrate the irradiation-resistant PEC water splitting based on nanoporous 4H-SiC arrays.A new two-step anodizing approach is adopted to prepare 4H-SiC nanoporous arrays with different porosity,that is,a constant low-voltage etching followed by a pulsed high-voltage etching.The constant-voltage etching and pulsed-voltage etching are adopted to control the diameter of the nanopores and the depth of the nanoporous arrays,respectively.It is found that the nanoporous arrays with medium porosity has the highest PEC current,because of the enhanced light absorption and the optimized transportation of charge carriers along the walls of the nanoporous arrays.The performance of the PEC water splitting of the nanoporous arrays is stable after the electron irradiation with the dose of 800 and 1600 k Gy,which indicates that 4H-SiC nanoporous arrays has great potential in the PEC water splitting under harsh environments.

Effect of X-ray irradiation on threshold voltage of AlGaN/GaN HEMTs with p-GaN and MIS Gates

Commercially available AlGaN/GaN high-electron-mobility transistors(HEMTs)are beginning to enter the public scene froma range of suppliers.Based on previous studies,commercial GaN-based electronics are expected to be tolerant to different types of irradiation in space.To test this assumption,we compared the characteristic electrical curves obtained at different X-ray irradiation doses for GaN HEMT devices manufactured by Infineon and Transphorm.The p-GaN-based device was found to be more robust with a stable threshold voltage,whereas the threshold voltage of the device with ametal-insulator-semiconductor gatewas found to shift first in the negative and then the positive direction.This dynamic phenomenon is caused by the releasing and trapping effects of radiation-induced charges in the dielectric layer and at the interface of irradiated devices.As such,the p-GaNgate-based GaN HEMT provides a promising solution for use as an electric source in space.

In situ TEM investigation of electron irradiation and aging-induced high-density nanoprecipitates in an Mg-10Gd-3Y-1Zn-0.5Zr alloy

In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3Y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the hardness.The results show that the hardness of the Mg alloy after irradiation for 10 h and aging for 9 h at 250℃ is 1.64 GPa,which is approximately 64% higher than that of the samples before being treated.It is mainly attributed to γ'precipitates on the basal plane after irradiation and the high-density nanoscale β'precipitates on the prismatic plane after aging,which should be closely related to the irradiation-induced homogenous clusters.The latter plays a key role in precipitation hardening.This result paves a way to improve the mechanical properties of metallic materials by tailoring the precipitation through irradiation and aging.

Microwave irradiation-induced alterations in physicochemical properties and methane adsorption capability of coals:An experimental study using carbon molecular sieve

In order to comprehend the applicability of microwave irradiation for recovering coalbed methane,it is necessary to evaluate the microwave irradiation-induced alterations in coals with varying levels of metamorphism.In this work,the carbon molecular sieve combined with KMnO_(4)oxidation was selected to fabricate carbon molecular sieve with diverse oxidation degrees,which can serve as model substances toward coals.Afterwards,the microwave irradiation dependences of pores,functional groups,and highpressure methane adsorption characteristics of model substances were studied.The results indicated that microwave irradiation causes rearrangement of oxygen-containing functional groups,which could block the micropores with a size of 0.40-0.60 nm in carbon molecular sieve;meanwhile,naphthalene and phenanthrene generated by macro-molecular structure pyrolysis due to microwave irradiation could block the micropores with a size of 0.70-0.90 nm.These alterations in micropore structure weaken the saturated methane adsorption capacity of oxidized carbon molecular sieve by 2.91%-23.28%,suggesting that microwave irradiation could promote methane desorption.Moreover,the increased mesopores found for oxidized carbon molecular sieve after microwave irradiation could benefit CH4 diffusion.In summary,the oxidized carbon molecular sieve can act as model substances toward coals with different ranks.Additionally,microwave irradiation is a promising technology to enhance coalbed methane recovery.

Effect of high-energy Ne ions irradiation on mechanical properties difference between Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5)metallic glass and crystalline W

In this paper,high-energy Ne ions were used to irradiate Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) metallic glass(MG)and crystalline W to investigate their difference in mechanical response after irradiation.The results showed that with the irradiation dose increased,the tensile micro-strain increased,nano-hardness increased from 7.11 GPa to 7.90 GPa and 8.62 GPa,Young’s modulus increased,and H3/E2 increased which indicating that the plastic deformability decreased in crystalline W.Under the same irradiation conditions,the Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG still maintained the amorphous structure and became more disordered despite the longer range and stronger displacement damage of Ne ions in Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG than in crystalline W.Unlike the irradiation hardening and embrittlement behavior of crystalline W,Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG showed the gradual decrease in hardness from 6.02 GPa to 5.89 GPa and 5.50 GPa,the decrease in modulus and the increase in plastic deformability with the increasing dose.Possibly,the irradiation softening and toughening phenomenon of Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG could provide new ideas for the design of nuclear materials.

Effect of three-volt moxibustion with helium-neon laser irradiation on quality of care in patients with lumbar radiculopathy spondylosis

BACKGROUND Lumbar radiculopathy spondylosis is a relatively common orthopedic disease with a high incidence rate.It most commonly occurs in the lumbar 4-5 and lumbar 5-sacral 1 vertebrae,which account for approximately 95%of cases.It mostly occurs in people aged 30-50 years old and greatly affects their quality of life.AIM To determine the effect of triple-voltage acupuncture combined with helium-neon laser irradiation on the quality of care and improvement of symptoms in patients with lumbar radiculopathy spondylolisthesis.METHODS In this study,we selected 120 patients with lumbar radiculopathy spondylosis who were treated at our hospital between June 2019 to June 2020.The patients were divided into control and observation groups according to the random number table method,with 60 patients in each group.Patients in the observation group were treated with three-volt moxibustion combined with helium-neon laser irradiation,and those in the control group were treated with lumbar traction.After 1 month of treatment,the lumbar pain scores,lumbar spine motor functions,clinical treatment effects,and nursing satisfaction of the two groups were compared.RESULTS The results showed that acupuncture combined with laser irradiation significantly improved the patients'clinical symptoms,i.e.,reduced their low back pain,significantly lower numerical rating scale pain scores in the observation group than in the control group,and better lumbar spine motility than in the control group,compared to lumbar traction.In addition,they were cared for.The treatment effectiveness rate of the observation group was 95.5%,which was significantly higher than that of the control group(81.67%).Satisfaction with care was higher than 90 points in both groups,but the difference was not statistically significant.CONCLUSION Our study provides a clinical rationale for the future treatment of patients with lumbar spine disease.However,further extensive research is needed for validation.

Development of a new irradiation-embrittlement prediction model for reactor pressure-vessel steels

Predicting the transition-temperature shift(TTS)induced by neutron irradiation in reactor pressure-vessel(RPV)steels is important for the evaluation and extension of nuclear power-plant lifetimes.Current prediction models may fail to properly describe the embrittlement trend curves of Chinese domestic RPV steels with relatively low Cu content.Based on the screened surveillance data of Chinese domestic and similar international RPV steels,we have developed a new fluencedependent model for predicting the irradiation-embrittlement trend.The fast neutron fluence(E>1 MeV)exhibited the highest correlation coefficient with the measured TTS data;thus,it is a crucial parameter in the prediction model.The chemical composition has little relevance to the TTS residual calculated by the fluence-dependent model.The results show that the newly developed model with a simple power-law functional form of the neutron fluence is suitable for predicting the irradiation-embrittlement trend of Chinese domestic RPVs,regardless of the effect of the chemical composition.

The impact of^(60)Co-γirradiation on the chemical constituents of Chuanxiong Rhizoma

Background:In order to clarify the inmpat ofγirradiation on the chemical composition of traditional Chinese medicine,this paper carefully choosed Chuanxiong Rhizoma to carry on a demonstration study.Methods:Through a meticulous assessment,a comprehensive comparison was made between the irradiated and unirradiated Chuanxiong Rhizoma samples.The property characteristics were investigated by colorimeter and electronic nose.The changes in chemical structures and contents was analyzed by fourier infrared spectroscopy,high performance liquid chromatography and fingerprinting.In a quest to uncover the presence of any new radiolysis products,cutting-edge techniques like ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry and gas chromatography-mass spectrometry were employed.Moreover,the difference of antioxidant activity were investigated.Results:The irradiation doses within 12 kGy had no significant effects on the content of the main chemical components,characteristics and in vitro antioxidant activity of Chuanxiong Rhizoma,while changes in some functional groups and degradation of some volatile oil components containing olefins need further study.Conclusion:This study indicates that^(60)Co-γirradiation is a stable method for sterilization of Chuanxiong Rhizoma.It’s also provide a reference for the establishment of irradiation standards for Chuanxiong Rhizoma and other aromatic medicinal plants.

Observation of therapeutic effect of lamp irradiation combined with purple gromwell oil gauze on alleviating intestinal colic in patients

BACKGROUND Intestinal colic is a common complication in patients who have undergone radical surgery for colorectal cancer.Traditional Chinese medicine has advantages,including safety and stability,for the treatment of intestinal colic.Lamp irra-diation for abdominal ironing has been applied in the treatment of many gas-trointestinal diseases.Purple gromwell oil has the effects of clearing heat,cooling blood,reducing swelling,and relieving pain.RESULTS The general effective rate in the observation group was 95.00%,which was significantly higher than that in the control group(86.67%,P<0.05).Before treatment,there was no significant difference in the duration of symptoms between the groups(P>0.05).After 1,2,3,and 4 d of treatment,the duration of symptoms in both groups were decreased,and the duration in the observation group was significantly lower than that in the control group(96.54±9.57 vs 110.45±11.23,87.26±12.07 vs 104.44±11.68,80.45±16.21 vs 99.44±14.95,73.18±15.58 vs 92.17±14.20;P<0.05).After 1,3,5,and 7 d of treatment,the NRS scores in both groups were decreased,and the NRS scores in the observation group were significantly lower than those in the control group(3.56±0.41 vs 4.04±0.58,3.07±0.67 vs 3.74±1.02,2.52±0.76 vs 3.43±0.85,2.03±0.58 vs 3.03±0.82;P<0.05).There was no significant difference in the rate of adverse reaction occurrence between the groups(P>0.05).CONCLUSION The use of lamp irradiation combined with purple gromwell oil gauze in patients with intestinal colic after radical surgery for colorectal cancer can reduce symptom duration,alleviate intestinal colic,and improve treatment efficacy,and this approach is safe.It is worth promoting the use of this treatment in clinical practice.

Protective and Regenerative Efficacy of a Plant Oil-Based Day and Night Cream: Investigated by a Novel Approach to Reveal the Impact of Blue Light Irradiation on Epidermal Barrier Integrity and Lipid Matrix

In recent years, the harmful effects of blue light (400 - 500 nm) as a component of visible light (400 - 700 nm) have increasingly gained attention of science, industry, and consumers. To date, only a few in vivo test methods for measuring the effects of blue light on the skin have been described. A direct measurement method that can detect the immediate effects of blue light on the epidermal permeability barrier (EPB) is still lacking. In this study, we present a new methodological approach that can be used to investigate both the protective and regenerative effects of cosmetic products on the EPB after blue light irradiation. In a study with 14 female volunteers, it was investigated whether the regular application of an O/W emulsion (day cream) can strengthen and protect the epidermal barrier against damaging blue light radiation of 60 J/cm2 (protective study design) and also whether a disruption of the epidermal barrier caused by blue light radiation is restored faster and better by the regular application of another O/W emulsion (night cream) than in product-untreated skin (regenerative study design). The two O/W emulsions are different in plant oil, active ingredient composition and texture. The seven-day treatment with the day cream initially led to a significant increase in the normalized lipid lamellae length in the intercellular space, whereas the irradiation with blue light after 24 hours led to a significant decrease in the lipid lamellae length in the untreated test area, but not in the area previously treated with the product. Regarding the regenerative study design, a two-day treatment with the night cream was able to restore a blue-light-induced decrease in lipid lamellae length in the intercellular space. In summary, with the study designs presented here, the protective and regenerative effect of two cosmetic products could be demonstrated for the first time on the integrity of the EPB after blue light irradiation and the data showed that the Lipbarvis® method is suitable for investigating the damaging effects of blue light on the EPB in vivo.

Investigation on the hydrodynamics of slab x-ray laser plasma by nonuiform line focused laser irradiation

Based on the two-dimensional model, this paper compares the hydrodynamics of slab x-ray laser plasma produced by different nonuniform line focused irradiations. It finds that the average intensity and the duration of laser pulse and the overall shape of the intensity distribution in the focal line have different influences on the plasma. Calculations show that the evolution of temperature variation is more sensitive to the pulse duration and the electron density variation is more sensitive to the pulse intensity. Pulses with duration of 200 ps to 500 ps and with intensity of 0.2 TW/cm2 to 1.0 TW/cm2 are proved acceptable in slab x-ray lasers.

Investigation of Well-Balanced kV X-Ray Imaging Conditions between Skin Dose and Image Noise for Dynamic Tumor Tracking Irradiation

Purpose: The purposes of this study were to estimate accumulated kV X-ray imaging dose throughout dynamic tumor tracking (DTT) irradiation by Vero 4DRT system and to address an analytical skin dose formula for well-balanced kV X-ray imaging conditions between skin dose and image noise. Method: First, skin dose was measured using kV X-ray tube, chamber, and water-equivalent phantoms. Next, imaging dose for six patients in DTT treatment was computed using log files. Subsequently, scattered dose ratio was calculated by amount of ionization in front of flat panel detector (FPD) for fields with size of maximum and the chamber for 0 - 200 mm-thickness phantoms and tube voltage of 60, 80, 100, 120 kV, respectively. Furthermore, image noise was computed from FPD images. Results: The skin dose was greater by a factor of 1.4 - 1.6 than those in Synergy XVI system. The image noise in FPD, ?was expressed as N = 0.045×(1/QFPDen)0.479, where QFPDen denotes amount of ionization in front of FPD. Then, skin dose, D (N, t, v) was formulated as (0.045/N)(1/0.479)/QFPDen/mAs (t, v) ×D/mAs (v), where QFPDen/mAs (t, v) and D/mAs (v) denote amount of ionization in front of FPD and skin dose per mAs, respectively. Using the formulae, it has been demonstrated that skin dose with 120 kV has become lower than any other tube voltage in this study. Conclusion: Using skin doses for the phantom, the skin dose throughout DTT irradiation was estimated as 0.50 Gy. Furthermore, skin dose by kV X-ray imaging was described as a function of image noise, phantom thickness, and tube voltage, suggesting image noise may be reduced with higher X-ray tube voltage in this phantom study.

3-59 Mechanism on X-ray Irradiation Suppressing Radioresistance in Non-small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) accounts for 85% of lung cancer, which is the leading cause of death in lung cancer patient. Routine treatment of NSCLC cannot effectively change the survival rate of patients, one important reason is the increased radioresistance of tumor cells after conventional radiotherapy.

3-44 Effects of X-ray and Carbon-ion Irradiation on Hematopoietic Cell Counts in the Mice Model

The hematological effects of space radiation contribute to the compromised immune defense in astronauts observed in the space environment as well as upon landing[1]. The complications associated with the hematopoietic syndrome include infection and internal hemorrhage. The decrease in peripheral blood cell counts after radiation serves not only as a marker for the severity of the exposure, but also as a marker for treatment and prognosis[2]. In the present research, we investigated the effects of whole-body heavy-ion (80 MeV/u carbon-ion) radiation and conventional X-ray (6 MV) radiation on peripheral blood cell counts in mice model. Time effects were determined to compare the effects of the different types of radiation.