AIM:To evaluate impact of radiation therapy dose escalation through intensity modulated radiation therapy with simultaneous integrated boost(IMRT-SIB).METHODS:We retrospectively reviewed the patients who underwent fou...AIM:To evaluate impact of radiation therapy dose escalation through intensity modulated radiation therapy with simultaneous integrated boost(IMRT-SIB).METHODS:We retrospectively reviewed the patients who underwent four-dimensional-based IMRT-SIBbased neoadjuvant chemoradiation protocol.During the concurrent chemoradiation therapy,radiation therapy was through IMRT-SIB delivered in 28 consecutive daily fractions with total radiation doses of 56 Gy to tumor and 5040 Gy dose-painted to clinical tumor volume,with a regimen at the discretion of the treating medical oncologist.This was followed by surgical tumor resection.We analyzed pathological completion response(p CR)rates its relationship with overall survival and event-freesurvival.RESULTS:Seventeen patients underwent dose escalation with the IMRT-SIB protocol between 2007 and 2014 and their records were available for analysis.Among the IMRT-SIB-treated patients,the toxicity appeared mild,the most common side effects were grade 1-3 esophagitis(46%)and pneumonitis(11.7%).There were no cardiac events.The Ro resection rate was 94%(n=16),the p CR rate was 47%(n=8),and the postoperative morbidity was zero.There was one mediastinal failure found,one patient had local failure at the anastomosis site,and the majority of failures were distant in the lung or bone.The 3-year diseasefree survival and overall survival rates were 41%(n=7)and 53%(n=9),respectively.CONCLUSION:The dose escalation through IMRT-SIB in the chemoradiation regimen seems responsible for down-staging the distal esophageal with well-tolerated complications.展开更多
AIM:To study the leakage-penumbra(LP)effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS:Leakage-penumbra dose profiles from 10 randomly selected prostat...AIM:To study the leakage-penumbra(LP)effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS:Leakage-penumbra dose profiles from 10 randomly selected prostate IMRT plans were studied.The IMRT plans were delivered by a Varian 21 EX linear accelerator equipped with a 120-leaf multileaf collimator(MLC).For each treatment plan created by the Pinnacle3 treatment planning system,a 3-dimensional LP dose distribution generated by 5 coplanar photon beams,starting from 0o with equal separation of 72 o,was investigated.For each photon beam used in the stepand-shoot IMRT plans,the first beam segment was set to have the largest area in the MLC leaf-sequencing,and was equal to the planning target volume(PTV).The overshoot effect(OSE)and the segment positional errors were measured using a solid water phantom with Kodak(TL and X-OMAT V)radiographic films.Film dosimetric analysis and calibration were carried out using a film scanner(Vidar VXR-16).The LP dose profiles were determined by eliminating the OSE and segment positional errors with specific individual irradiations.RESULTS:A non-uniformly distributed leaf LP dose ranging from 3%to 5%of the beam dose was measured in clinical IMRT beams.An overdose at the gap between neighboring segments,represented as dose peaks of up to 10%of the total BP,was measured.The LP effect increased the dose to the PTV and surrounding critical tissues.In addition,the effectdepends on the number of beams and segments for each beam.Segment positional error was less than the maximum tolerance of 1 mm under a dose rate of 600 monitor units per minute in the treatment plans.The OSE varying with the dose rate was observed in all photon beams,and the effect increased from 1 to 1.3 Gy per treatment of the rectal intersection.As the dosimetric impacts from the LP effect and OSE may increase the rectal post-radiation effects,a correction of LP was proposed and demonstrated for the central beam profile for one of the planned beams.CONCLUSION:We concluded that the measured dosimetric impact of the LP dose inaccuracy from photon beam segment in step-and-shoot IMRT can be corrected.展开更多
Objective:Serum prostate specific antigen(PSA)is commonly used to evaluate treatment response after definitive radiation therapy(RT).However,PSA levels can temporarily rise without a clear reason,termed“PSA bounce”,...Objective:Serum prostate specific antigen(PSA)is commonly used to evaluate treatment response after definitive radiation therapy(RT).However,PSA levels can temporarily rise without a clear reason,termed“PSA bounce”,and often engender great anxiety for both patients and physicians.The present study aimed to determine the prevalence and factors that predict“PSA bounce”after intensity-modulated radiation therapy(IMRT),and the relevance to biochemical failure and cancer recurrence in an Asian population.Methods:We retrospectively reviewed 206 patients who received IMRT for prostate cancer from 2004 to 2012 in the National Cancer Centre Singapore.These patients were followed up with regular PSA monitoring.We defined“PSA bounce”as a rise of 0.1 ng/mL,followed by two consecutive falls.Patients with biochemical failure(PSA nadir t 2 ng/mL)were further evaluated for cancer recurrence.Results:Sixty-one patients(29.6%)experienced“PSA bounce”,at a median time of 16 months and lasted for 12 months.Age remained the most consistent predictor of the incidence,duration and extent of“PSA bounce”.Other contributory factors included baseline PSA,Gleason score and PSA nadir.Hormonal therapy and prostate volume did not affect this phenomenon.Sixteen patients(7.8%)developed biochemical recurrence,at median time of 32 months,of which 11 were confirmed to have metastatic disease.The median follow-up time was 71 months.展开更多
Objective: To evaluate the clinical effects of concurrent and sequential therapy for middle and advanced stage non-small cell lung cancer (NSCLC) useing IMRT combined with NP regimen chemotherapy. Methods: Eighty pati...Objective: To evaluate the clinical effects of concurrent and sequential therapy for middle and advanced stage non-small cell lung cancer (NSCLC) useing IMRT combined with NP regimen chemotherapy. Methods: Eighty patients with middle and advanced stage NSCLC were randomized into two groups. Forty patients were underwent sequential therapy and other 40 patients were underwent concurrent therapy. IMRT was used in radiotherapy and NP regimen of vinorelbine+cispatin (NP) was used in chemotherapy. Results: (1) The overall response (CR+PR) rate was 75% in concurrent group and 45% in sequential group (P<0.05); (2) The treatment courses were 84 days and 140 days for concurrent group and sequential group respectively (P<0.05); (3) One-year survival rate in concurrent group was 72.4% and 52.3% in sequential group respectively; (4) The toxic effects can be tolerable by all of patients. Conclusion: The concurrent chemo-radiotherapy has better overall re- sponse, one-year survival rate and shorter treatment course than the sequential chemo-radiotherapy, so it is a better method for the treatment of middle and advanced stage NSCLC, but the long term survival rate will be studied.展开更多
Outcomes in patients with gastric cancer in the United States remain disappointing, with a five-year overall survival rate of approximately 23%. Given high rates of local-regional control following surgery, a strong r...Outcomes in patients with gastric cancer in the United States remain disappointing, with a five-year overall survival rate of approximately 23%. Given high rates of local-regional control following surgery, a strong rationale exists for the use of adjuvant radiation therapy. Randomized trials have shown superior local control with adjuvant radiotherapy and improved overall survival with adjuvant chemoradiation. The benefit of adjuvant chemoradiation in patients who have undergone D2 lymph node dissection by an experienced surgeon is not known, and the benefit of adjuvant radiation therapy in addition to adjuvant chemotherapy continues to be defined. In unresectable disease, chemoradiation allows long-term survival in a small number of patients and provides effective palliation. Most trials show a benefit to combined modality therapy compared to chemotherapy or radiation therapy alone. The use of pre-operative, intra-operative, 3D conformal, and intensity modulated radiation therapy in gastric cancer is promising but requires further study. The current article reviews the role of radiation therapy in the treatment of resectable and unresectable gastric carcinoma, focusing on current recommendations in the United States.展开更多
Based on the diffusion approximate theory （DA）, a theoretical model about the distribution of the intensity of a narrow collimation beam illuminating on a semi-lnfinite biological tissue is developed. In order to ve...Based on the diffusion approximate theory （DA）, a theoretical model about the distribution of the intensity of a narrow collimation beam illuminating on a semi-lnfinite biological tissue is developed. In order to verify the correctness of the model, a novel method of measuring the distributions of the intensity of light in Intralipid-10% suspension at 650 nm is presented and ts of the distributions of the distance-dependent intensity of scattering light in different directions are made. The investigations show that the results from our diffusion model are in good agreement with the experimental results beyond and in the areas around the light source, and the distance-dependent intensity in the incident direction attenuates approximately in the exponential form. Furthermore, our theoretic results indicate the anisotropic characteristics of the intensity in different directions of scattering light inside the biological tissue.展开更多
The incidence of hepatocellular carcinoma(HCC)is increasing in the United States,and 50%-75%o patients with HCC will develop metastatic disease Orbital metastases from HCC are extremely rare.We report the case of a 52...The incidence of hepatocellular carcinoma(HCC)is increasing in the United States,and 50%-75%o patients with HCC will develop metastatic disease Orbital metastases from HCC are extremely rare.We report the case of a 52-year-old male with known metastatic HCC,who presented with severe proptosis and diplopia.An orbital mass was identified on magnetic resonance imaging(MRI)and confirmed to have hypermetabolic activity on positron emission tomography/computed tomography.He received a palliative course of external beam radiation therapy to the right orbit.Intensity modulated radiation therapy (IMRT)was used to allow sparing of critical norma tissues in close proximity to the tumor.One month after completion of IMRT to 58 Gray in 30 fractions delivered over 6 wk,the patient had a complete clinical,radiologic(MRI)and symptomatic response The patient continues to have local control in the orbi 1.7 years after therapy completion.All critical norma structures were kept below the tolerance dose using IMRT,and no toxicities were observed.展开更多
To the Editor:Graft-versus-host disease(GVHD)is a rare but fatal complication after solid organ transplantation(SOT),with an incidence of 0.2–2.0%.Recent retrospective studies have shown a mortality rate of approxima...To the Editor:Graft-versus-host disease(GVHD)is a rare but fatal complication after solid organ transplantation(SOT),with an incidence of 0.2–2.0%.Recent retrospective studies have shown a mortality rate of approximately 85–98%among patients with SOT-GVHD.[1]Various drugs and methods have been shown to improve or alleviate clinical symptoms,but no effective treatments for GVHD currently exist.Recent clinical experience with SOTGVHD treatment is mixed and limited,including systemic or partial corticosteroid support,the use of Janus kinase(JAK)inhibitors,allogeneic hematopoietic cell transplantation(alloHCT),and donor-targeted serotherapy.Since the number of lymphocytes transplanted with the organ may be a risk factor for GVHD,reducing the number of donor lymphocytes seems beneficial.Intensity-modulated radiation therapy(IMRT)is a type of radiotherapy that uses optimized,non-uniform radiation beam intensities on the patient.[2]Local allograft irradiation has also been used to treat severe resistant rejection after liver transplantation(LT)in previous studies.[3]Based on this,we hypothesized that whole-liver IMRT at a low dosage could be used as a rescue therapy to control acute GVHD after LT by reducing the number of donor-derived immune cells.展开更多
Objective:The incidence of primary tracheal neoplasm is extremely rare.Squamous cell carcinoma(SCC)is the most prevalent histological type of tracheal malignancy.Postoperative adjuvant radiotherapy can be considered a...Objective:The incidence of primary tracheal neoplasm is extremely rare.Squamous cell carcinoma(SCC)is the most prevalent histological type of tracheal malignancy.Postoperative adjuvant radiotherapy can be considered as a curative management option.However,there are limited data available on the use of radiotherapy or concurrent chemoradiotherapy for tracheal cancer,particularly intensity-modulated radiotherapy.Patient and methods:Herein,we present a case report of a young adult male diagnosed with primary SCC of the trachea who underwent postoperative concurrent chemoradiotherapy utilizing intensity-modulated radiation therapy(IMRT).The treatment included 50.4 Gy radiation in 28fractions and two cycles of chemotherapy.Results:The patient experienced gradeⅠdermatitis and gradeⅡgranulocytosis.Follow-up showed no evidence of recurrence or significant adverse effects.The patient achieved 5-year long-term survival with good quality of life.Conclusion:Postoperative concurrent chemoradiotherapy using IMRT is effective for primary tracheal carcinoma,offering long-term survival and quality of life benefits.展开更多
In order to solve for temperature fields in microwave heating for recycling asphalt mixtures, a two-dimensional heat transfer model for the asphalt mixtures within the heating range is built based on the theory of uns...In order to solve for temperature fields in microwave heating for recycling asphalt mixtures, a two-dimensional heat transfer model for the asphalt mixtures within the heating range is built based on the theory of unsteady heat conduction. Four onedimensional heat transfer models are established for the asphalt mixtures outside the heating range, which are simplified into four half-infinite solids. The intensity of the radiation electric field is calculated through experiment by using heating water loads. It is suggested that the mathematical model of boundary conditions can be established in two ways, which are theoretical deduction and experimental reverse. The actual temperature field is achieved by fitting temperatures of different positions collected in the heating experiment. The simulant temperature field, which is solved with the Matlab PDE toolbox, is in good agreement with the actual temperature field. The results indicate that the proposed models have high precision and can be directly used to calculate the temperature distribution of asphalt pavements.展开更多
Microcystins(MCs)are one of the most prevalent cyanotoxins and pose significant risks to aquatic ecosystems and human health,particularly in lakes used as drinking water sources.However,knowledge about the MC concentr...Microcystins(MCs)are one of the most prevalent cyanotoxins and pose significant risks to aquatic ecosystems and human health,particularly in lakes used as drinking water sources.However,knowledge about the MC concentrations in plateau lakes experiencing high solar radiation is scarce.This study investigated the spatial-temporal distribution of MCs in eight Yunnan Plateau lakes in China,focusing on their relationships with environmental factors.Water samples(n=63)were collected during summer and winter seasons and analyzed for MC concentrations along with a suite of environmental variables.Results revealed significant seasonal and spatial variations in MC concentrations,with higher levels in eutrophic lakes Dianchi,Erhai,and Xingyunhu.Notably,mean MC concentrations in Lake Dianchi during summer and Erhai during winter exceeded the World Health Organization’s provisional guideline of 1μg/L for drinking water.Seasonal analyses revealed distinct regulatory mechanisms:MC concentrations in summer were positively correlated with total phosphorus,total nitrogen,turbidity,and chlorophyll a,reflecting the influence of eutrophication on cyanobacterial growth.While solar radiation intensity(SRI)exhibited a dual role:moderate SRI in winter was associated with higher MC levels,whereas higher SRI in summer suppressed MC production,likely due to photoinhibition or MC degradation.Strikingly,water temperature showed no significant correlation with MC concentrations,suggesting that high solar radiation in the Yunnan Plateau may override temperature-dependent effects on cyanobacterial growth.These findings highlight the importance of nutrient management and the regulatory role of solar radiation in regulating MC production in high-altitude lakes.The study underscores the need for region-specific strategies to mitigate cyanobacterial risks,particularly in drinking water source lakes,by integrating nutrient control and the unique light regime of plateau ecosystems.展开更多
AIM To analyse clinical and dosimetric results of helical tomotherapy(HT)and volumetric modulated arc therapy(VMAT)in complex adjuvant breast and nodes irradiation.METHODS Seventy-three patients were included(31 HT an...AIM To analyse clinical and dosimetric results of helical tomotherapy(HT)and volumetric modulated arc therapy(VMAT)in complex adjuvant breast and nodes irradiation.METHODS Seventy-three patients were included(31 HT and 42 VMAT).Dose were 63.8 Gy(HT)and 63.2 Gy(VMAT)in the tumour bed,52.2 Gy in the breast,50.4 Gy in supraclavicular nodes(SCN)and internal mammary chain(IMC)with HT and 52.2 Gy and 49.3 Gy in IMC and SCN with VMAT in 29 fractions.Margins to particle tracking velocimetry were greater in the VMAT cohort(7 mm vs 5 mm).RESULTS For the HT cohort,the coverage of clinical target volumes was as follows:Tumour bed:99.4%±2.4%;breast:98.4%±4.3%;SCN:99.5%±1.2%;IMC:96.5%±13.9%.For the VMAT cohort,the coverage was as follows:Tumour bed:99.7%±0.5%,breast:99.3%±0.7%;SCN:99.6%±1.4%;IMC:99.3%±3%.For ipsilateral lung,Dmean and V20 were 13.6±1.2 Gy,21.1%±5%(HT)and 13.6±1.4 Gy,20.1%±3.2%(VMAT).Dmean and V30 of the heart were 7.4±1.4 Gy,1%±1%(HT)and 10.3±4.2 Gy,2.5%±3.9%(VMAT).For controlateral breast Dmean was 3.6±0.2 Gy(HT)and 4.6±0.9 Gy(VMAT).Acute skin toxicity grade 3 was 5%in the two cohorts.CONCLUSION HT and VMAT in complex adjuvant breast irradiation allow a good coverage of target volumes with an acceptable acute tolerance.A longer follow-up is needed to assess the impact of low doses to healthy tissues.展开更多
Impact flash occurs when objects collide at supersonic speeds and can be used for real-time damage assessment when weapons rely on kinetic energy to destroy targets.However,the mechanism of impact flash remains unclea...Impact flash occurs when objects collide at supersonic speeds and can be used for real-time damage assessment when weapons rely on kinetic energy to destroy targets.However,the mechanism of impact flash remains unclear.A series of impact flash experiments of flat-head long-rod projectiles impacting thin target plates were performed with a two-stage light gas gun.The impact flash spectra for 6061 aluminum at 1.3e3.2 km/s collision speeds were recorded with a high-speed camera,a photoelectric sensor,and a time-resolved spectrometer.The intensity of the impact flash exhibited a pulse characteristic with time.The intensity(I)increased with impact velocity(V0)according to IfVn 0,where n?4.41 for V0>2 km/s.However,for V0<2 km/s,n?2.21,and the intense flash duration is an order of magnitude less than that of higher V0.When V0>2 km/s,a continuous spectrum(thermal radiation background)was observed and increased in intensity with V0.However,for V0<2 km/s,only atomic line spectra were detected.There was no aluminum spectral lines for V0<2 km/s,which indicated that it had not been vaporized.The initial intense flash was emission from excited and ionized ambient gases near the impact surface,and had little relationship with shock temperature rise,indicating a new mechanism of impact flash.展开更多
This paper mainly aims at the modeling problem of the photovoltaic (PV) array with a 30 kW PV grid-connected generation system. An iterative method for the time-varying parameters is proposed to model a plant of PV ar...This paper mainly aims at the modeling problem of the photovoltaic (PV) array with a 30 kW PV grid-connected generation system. An iterative method for the time-varying parameters is proposed to model a plant of PV array. The relationship of PV cell and PV array is obtained and the solution for PV array model is unique. The PV grid-connected generation system is used to demonstrate the effectiveness of the proposed method by comparing the calculated values with the actual output of the system.展开更多
In order to explore a dose distribution verification procedure of intensity modulated radiation therapy （IMRT） for nasopharyngeal carcinoma （NPC） and establish its evaluation criteria, we performed 35 two-dimensio...In order to explore a dose distribution verification procedure of intensity modulated radiation therapy （IMRT） for nasopharyngeal carcinoma （NPC） and establish its evaluation criteria, we performed 35 two-dimensional （2D） patient-specific IMRT verifications over the year i006. The percent of pixels passing 7 and the normalized agreement test （NAT） index were mainly used to represent the agreement between the measured and computed dose distributions with three criteria （2%/2 mm, 3%/3 mm and 5%/3 mm） as recommended in the literature. The results were that all cases passed through verifications with three criteria except that the NAT index of one case was beyond the limitation, and the three tolerance levels of 2%/2mm, 3%/3 mm and 5%/3 mm produced similar clinical verification results but led to different percent of pixels passing Y and NAT index. Our data showed that the percent of pixels passing y and the NAT index were complementary to evaluate future IMRT verifications as two significant metrics. Due to the influence of the noise and the trait of the software, we considered an IMRT plan as acceptable in case of the percent ofpixels passing y 〉95% and the NAT index 〈5 with the 5%/3 mm criteria for IMRT patient-specific quality assurance （QA）.展开更多
Solar energy has always been a kind of energy with large reserves and wide application.It is well utilized through solar absorbers.In our study,the finite difference time domain method(FDTD)is used to simulate the abs...Solar energy has always been a kind of energy with large reserves and wide application.It is well utilized through solar absorbers.In our study,the finite difference time domain method(FDTD)is used to simulate the absorber composed of refractory metal materials,and its absorption performance and thermal emission performance are obtained.The ultra-wide band of 200 nm-3000 nm reaches 95.93%absorption efficiency,of which the bandwidth absorption efficiency of2533 nm(200 nm-2733 nm)is greater than 90%.The absorption efficiency in the whole spectrum range(200 nm-2733 nm)is 97.17%on average.The multilayer nanodisk structure of the absorber allows it to undergo strong surface plasmon resonance and near-field coupling when irradiated by incident light.The thermal emission performance of the absorber enables it to also be applied to the thermal emitter.The thermal emission efficiency of 95.37%can be achieved at a high temperature of up to 1500 K.Moreover,the changes of polarization and incident angle do not cause significant changes in absorption.Under the gradual change of polarization angle(0°-90°),the absorption spectrum maintains a high degree of consistency.As the incident angle increases from 0°to 60°,there is still 85%absorption efficiency.The high absorption efficiency and excellent thermal radiation intensity of ultra-wideband enable it to be deeply used in energy absorption and conversion applications.展开更多
To study the properties of a new surface-type infrared decoy,the numerical dispersion model and the infrared radiance model of the plates are established. In addition,the temperature of a single plate was measured dur...To study the properties of a new surface-type infrared decoy,the numerical dispersion model and the infrared radiance model of the plates are established. In addition,the temperature of a single plate was measured during combustion experiment,and the spatial position and infrared radiance of each plate are calculated in plate cloud by the two models respectively. Furthermore,the radar images of the plate cloud are simulated and analyzed in dependence of time and direction for single and multiple launching. The result shows that the surface-type infrared decoy can be a point source of interference when the missile is remote tracking. In the meanwhile,the plates cloud shelters the infrared characteristics of the plume and jets of aircraft when the missile is on IR imaging guidance mode. Moreover,With the analysis of the plate cloud dispersion at different intervals and the infrared radiation intensity in the case of different launching number,it can be concluded that a comfortable launching interval can maintain a continuous plate cloud,launching the decoys simultaneously increase the increment of the radiation intensity obviously,the multiple launching is an effective way to enhance the interference property of the decoy.展开更多
Chondrosarcomas are malignant bone tumors which develop as a cartilaginous differentiation of primary mesenchymal cells and the second most frequently seen malignant tumor of the bone after osteosarcoma. These maligna...Chondrosarcomas are malignant bone tumors which develop as a cartilaginous differentiation of primary mesenchymal cells and the second most frequently seen malignant tumor of the bone after osteosarcoma. These malignancies are slowly growing non-epithelial tumors with unknown etiology and most frequently seen during the 4 decades of life. They are frequently localized on pelvis, ribs and long bones. Nasal septum CSs are very rarely seen malignancies. They originate from septal mucosa or cartilage and it is difficult to make a diagnosis unless they reach a certain size. A few cases of CSs with nasal septum have been reported in the literature. In cases of CSs, surgery is the gold standard treatment modality;however in surgically unresectable cases or close to margins, radiotherapy plays a significant role in primary and adjuvant treatment. Based on the position of the tumor in head and neck and extremely closeness of the tumor to vital organs as optic nerve, chiasm and brain, image guided-intensity modulated radiation therapy (IG-IMRT) becomes very effective and reliable modalities and may be a favorable treatment alternative.展开更多
Based on the analysis of heat radiation intensity from flame, a new mathematical model ofthe tube-wall temperatmp of heated tubes is developed by taking down-fired, upright-tube cylindricalfurnace for example. The pro...Based on the analysis of heat radiation intensity from flame, a new mathematical model ofthe tube-wall temperatmp of heated tubes is developed by taking down-fired, upright-tube cylindricalfurnace for example. The proposed mathematical model can be employed to indicate both the positionand size of the hot spot at fire-facing wall of heated tube of combustion chamber, and is characteristicof simplicity and efficiency If coupled with thermoelectric couple or infrared viewer, the presentedlocation method of combustion hot spot can offer engineers very valuable proposal to keep furnacerunning more safely The same is true for any other type of tubular furnaces.展开更多
Low-noise terahertz(THz)radiation over 100 MV/cm generation by a linearly-polarized relativistic laser pulse interacting with a near-critical-density(NCD)plasma slab is studied by theory and particle-in-cell(PIC)simul...Low-noise terahertz(THz)radiation over 100 MV/cm generation by a linearly-polarized relativistic laser pulse interacting with a near-critical-density(NCD)plasma slab is studied by theory and particle-in-cell(PIC)simulations.A theoretical model is established to examine the dipole-like radiation emission.The THz radiation is attributed to the singlecycle low-frequency surface current,which is longitudinally constrained by the quasi-equilibrium established by the laser ponderomotive force and the ponderomotively induced electrostatic force.Through theoretical analysis,the spatiotemporal characteristics,polarization property of the THz radiation,and the relation between the radiation strength with the initial parameters of driving laser and plasma are obtained,which are in good consistence with the PIC simulation results.Furthermore,it is found by PIC simulations that the generation of thermal electrons can be suppressed within the appropriate parameter regime,resulting in a clear THz radiation waveform.The appropriate parameter region is given for generating a low-noise intense THz radiation with peak strength reaching 100 MV/cm,which could find potential applications in nonlinear THz physics.展开更多
文摘AIM:To evaluate impact of radiation therapy dose escalation through intensity modulated radiation therapy with simultaneous integrated boost(IMRT-SIB).METHODS:We retrospectively reviewed the patients who underwent four-dimensional-based IMRT-SIBbased neoadjuvant chemoradiation protocol.During the concurrent chemoradiation therapy,radiation therapy was through IMRT-SIB delivered in 28 consecutive daily fractions with total radiation doses of 56 Gy to tumor and 5040 Gy dose-painted to clinical tumor volume,with a regimen at the discretion of the treating medical oncologist.This was followed by surgical tumor resection.We analyzed pathological completion response(p CR)rates its relationship with overall survival and event-freesurvival.RESULTS:Seventeen patients underwent dose escalation with the IMRT-SIB protocol between 2007 and 2014 and their records were available for analysis.Among the IMRT-SIB-treated patients,the toxicity appeared mild,the most common side effects were grade 1-3 esophagitis(46%)and pneumonitis(11.7%).There were no cardiac events.The Ro resection rate was 94%(n=16),the p CR rate was 47%(n=8),and the postoperative morbidity was zero.There was one mediastinal failure found,one patient had local failure at the anastomosis site,and the majority of failures were distant in the lung or bone.The 3-year diseasefree survival and overall survival rates were 41%(n=7)and 53%(n=9),respectively.CONCLUSION:The dose escalation through IMRT-SIB in the chemoradiation regimen seems responsible for down-staging the distal esophageal with well-tolerated complications.
文摘AIM:To study the leakage-penumbra(LP)effect with a proposed correction method for the step-and-shoot intensity modulated radiation therapy(IMRT).METHODS:Leakage-penumbra dose profiles from 10 randomly selected prostate IMRT plans were studied.The IMRT plans were delivered by a Varian 21 EX linear accelerator equipped with a 120-leaf multileaf collimator(MLC).For each treatment plan created by the Pinnacle3 treatment planning system,a 3-dimensional LP dose distribution generated by 5 coplanar photon beams,starting from 0o with equal separation of 72 o,was investigated.For each photon beam used in the stepand-shoot IMRT plans,the first beam segment was set to have the largest area in the MLC leaf-sequencing,and was equal to the planning target volume(PTV).The overshoot effect(OSE)and the segment positional errors were measured using a solid water phantom with Kodak(TL and X-OMAT V)radiographic films.Film dosimetric analysis and calibration were carried out using a film scanner(Vidar VXR-16).The LP dose profiles were determined by eliminating the OSE and segment positional errors with specific individual irradiations.RESULTS:A non-uniformly distributed leaf LP dose ranging from 3%to 5%of the beam dose was measured in clinical IMRT beams.An overdose at the gap between neighboring segments,represented as dose peaks of up to 10%of the total BP,was measured.The LP effect increased the dose to the PTV and surrounding critical tissues.In addition,the effectdepends on the number of beams and segments for each beam.Segment positional error was less than the maximum tolerance of 1 mm under a dose rate of 600 monitor units per minute in the treatment plans.The OSE varying with the dose rate was observed in all photon beams,and the effect increased from 1 to 1.3 Gy per treatment of the rectal intersection.As the dosimetric impacts from the LP effect and OSE may increase the rectal post-radiation effects,a correction of LP was proposed and demonstrated for the central beam profile for one of the planned beams.CONCLUSION:We concluded that the measured dosimetric impact of the LP dose inaccuracy from photon beam segment in step-and-shoot IMRT can be corrected.
文摘Objective:Serum prostate specific antigen(PSA)is commonly used to evaluate treatment response after definitive radiation therapy(RT).However,PSA levels can temporarily rise without a clear reason,termed“PSA bounce”,and often engender great anxiety for both patients and physicians.The present study aimed to determine the prevalence and factors that predict“PSA bounce”after intensity-modulated radiation therapy(IMRT),and the relevance to biochemical failure and cancer recurrence in an Asian population.Methods:We retrospectively reviewed 206 patients who received IMRT for prostate cancer from 2004 to 2012 in the National Cancer Centre Singapore.These patients were followed up with regular PSA monitoring.We defined“PSA bounce”as a rise of 0.1 ng/mL,followed by two consecutive falls.Patients with biochemical failure(PSA nadir t 2 ng/mL)were further evaluated for cancer recurrence.Results:Sixty-one patients(29.6%)experienced“PSA bounce”,at a median time of 16 months and lasted for 12 months.Age remained the most consistent predictor of the incidence,duration and extent of“PSA bounce”.Other contributory factors included baseline PSA,Gleason score and PSA nadir.Hormonal therapy and prostate volume did not affect this phenomenon.Sixteen patients(7.8%)developed biochemical recurrence,at median time of 32 months,of which 11 were confirmed to have metastatic disease.The median follow-up time was 71 months.
基金Supported by a grant from Health Bureau of Lianyungang City’s Fund Program (No. 05051).
文摘Objective: To evaluate the clinical effects of concurrent and sequential therapy for middle and advanced stage non-small cell lung cancer (NSCLC) useing IMRT combined with NP regimen chemotherapy. Methods: Eighty patients with middle and advanced stage NSCLC were randomized into two groups. Forty patients were underwent sequential therapy and other 40 patients were underwent concurrent therapy. IMRT was used in radiotherapy and NP regimen of vinorelbine+cispatin (NP) was used in chemotherapy. Results: (1) The overall response (CR+PR) rate was 75% in concurrent group and 45% in sequential group (P<0.05); (2) The treatment courses were 84 days and 140 days for concurrent group and sequential group respectively (P<0.05); (3) One-year survival rate in concurrent group was 72.4% and 52.3% in sequential group respectively; (4) The toxic effects can be tolerable by all of patients. Conclusion: The concurrent chemo-radiotherapy has better overall re- sponse, one-year survival rate and shorter treatment course than the sequential chemo-radiotherapy, so it is a better method for the treatment of middle and advanced stage NSCLC, but the long term survival rate will be studied.
文摘Outcomes in patients with gastric cancer in the United States remain disappointing, with a five-year overall survival rate of approximately 23%. Given high rates of local-regional control following surgery, a strong rationale exists for the use of adjuvant radiation therapy. Randomized trials have shown superior local control with adjuvant radiotherapy and improved overall survival with adjuvant chemoradiation. The benefit of adjuvant chemoradiation in patients who have undergone D2 lymph node dissection by an experienced surgeon is not known, and the benefit of adjuvant radiation therapy in addition to adjuvant chemotherapy continues to be defined. In unresectable disease, chemoradiation allows long-term survival in a small number of patients and provides effective palliation. Most trials show a benefit to combined modality therapy compared to chemotherapy or radiation therapy alone. The use of pre-operative, intra-operative, 3D conformal, and intensity modulated radiation therapy in gastric cancer is promising but requires further study. The current article reviews the role of radiation therapy in the treatment of resectable and unresectable gastric carcinoma, focusing on current recommendations in the United States.
基金Project supported by the National Natural Science Foundation of China （Grant No 60278007）, the Natural Science Foundation of Tianjin （Grant No 033601311） and the Natural Science Foundation of Guangdong Province （Grant No 04011427）.
文摘Based on the diffusion approximate theory （DA）, a theoretical model about the distribution of the intensity of a narrow collimation beam illuminating on a semi-lnfinite biological tissue is developed. In order to verify the correctness of the model, a novel method of measuring the distributions of the intensity of light in Intralipid-10% suspension at 650 nm is presented and ts of the distributions of the distance-dependent intensity of scattering light in different directions are made. The investigations show that the results from our diffusion model are in good agreement with the experimental results beyond and in the areas around the light source, and the distance-dependent intensity in the incident direction attenuates approximately in the exponential form. Furthermore, our theoretic results indicate the anisotropic characteristics of the intensity in different directions of scattering light inside the biological tissue.
文摘The incidence of hepatocellular carcinoma(HCC)is increasing in the United States,and 50%-75%o patients with HCC will develop metastatic disease Orbital metastases from HCC are extremely rare.We report the case of a 52-year-old male with known metastatic HCC,who presented with severe proptosis and diplopia.An orbital mass was identified on magnetic resonance imaging(MRI)and confirmed to have hypermetabolic activity on positron emission tomography/computed tomography.He received a palliative course of external beam radiation therapy to the right orbit.Intensity modulated radiation therapy (IMRT)was used to allow sparing of critical norma tissues in close proximity to the tumor.One month after completion of IMRT to 58 Gray in 30 fractions delivered over 6 wk,the patient had a complete clinical,radiologic(MRI)and symptomatic response The patient continues to have local control in the orbi 1.7 years after therapy completion.All critical norma structures were kept below the tolerance dose using IMRT,and no toxicities were observed.
基金supported by a grant from the Key Research and Development Plan of Hubei Province(No.2022BCA015).
文摘To the Editor:Graft-versus-host disease(GVHD)is a rare but fatal complication after solid organ transplantation(SOT),with an incidence of 0.2–2.0%.Recent retrospective studies have shown a mortality rate of approximately 85–98%among patients with SOT-GVHD.[1]Various drugs and methods have been shown to improve or alleviate clinical symptoms,but no effective treatments for GVHD currently exist.Recent clinical experience with SOTGVHD treatment is mixed and limited,including systemic or partial corticosteroid support,the use of Janus kinase(JAK)inhibitors,allogeneic hematopoietic cell transplantation(alloHCT),and donor-targeted serotherapy.Since the number of lymphocytes transplanted with the organ may be a risk factor for GVHD,reducing the number of donor lymphocytes seems beneficial.Intensity-modulated radiation therapy(IMRT)is a type of radiotherapy that uses optimized,non-uniform radiation beam intensities on the patient.[2]Local allograft irradiation has also been used to treat severe resistant rejection after liver transplantation(LT)in previous studies.[3]Based on this,we hypothesized that whole-liver IMRT at a low dosage could be used as a rescue therapy to control acute GVHD after LT by reducing the number of donor-derived immune cells.
基金supported by the National Natural Science Foundation of China(82460958)the National Superior Specialty of TCM(National TCM Medical Policy Letter(2024)No.90)the Guangxi Key Discipline Construction Project of Traditional Chinese Medicine(GZXK-Z-20-20)
文摘Objective:The incidence of primary tracheal neoplasm is extremely rare.Squamous cell carcinoma(SCC)is the most prevalent histological type of tracheal malignancy.Postoperative adjuvant radiotherapy can be considered as a curative management option.However,there are limited data available on the use of radiotherapy or concurrent chemoradiotherapy for tracheal cancer,particularly intensity-modulated radiotherapy.Patient and methods:Herein,we present a case report of a young adult male diagnosed with primary SCC of the trachea who underwent postoperative concurrent chemoradiotherapy utilizing intensity-modulated radiation therapy(IMRT).The treatment included 50.4 Gy radiation in 28fractions and two cycles of chemotherapy.Results:The patient experienced gradeⅠdermatitis and gradeⅡgranulocytosis.Follow-up showed no evidence of recurrence or significant adverse effects.The patient achieved 5-year long-term survival with good quality of life.Conclusion:Postoperative concurrent chemoradiotherapy using IMRT is effective for primary tracheal carcinoma,offering long-term survival and quality of life benefits.
基金The Key Project of Science and Technology of Ministryof Education (No.105085)the Specialized Research Fund of Science andTechnology Production Translation of Jiangsu Province (No.BA2006068).
文摘In order to solve for temperature fields in microwave heating for recycling asphalt mixtures, a two-dimensional heat transfer model for the asphalt mixtures within the heating range is built based on the theory of unsteady heat conduction. Four onedimensional heat transfer models are established for the asphalt mixtures outside the heating range, which are simplified into four half-infinite solids. The intensity of the radiation electric field is calculated through experiment by using heating water loads. It is suggested that the mathematical model of boundary conditions can be established in two ways, which are theoretical deduction and experimental reverse. The actual temperature field is achieved by fitting temperatures of different positions collected in the heating experiment. The simulant temperature field, which is solved with the Matlab PDE toolbox, is in good agreement with the actual temperature field. The results indicate that the proposed models have high precision and can be directly used to calculate the temperature distribution of asphalt pavements.
基金supported by the Yunnan Provincial Department of Science and Technology(202401AS070119,202103AC100001,202449CE340003)Yunnan Provincial Department of Human Resources and Social Security(202505AO120004)+4 种基金Yunnan Provincial Council of Academicians and Experts Workstations(202405AF140006)Scientific Research and Innovation Project of Postgraduate Students in the Academic Degree of Yunnan University(KC23234416).H.W.P.was supported by the US National Science Foundation,projects(1840715,2108917,2418066)the US National Institutes of Health(1P01ES028939-06).S.A.W.thanks the New Zealand Ministry of Business,Innovation and Employment research programme Our Lakes,Our Future(CAWX2305)for support.E.J.is thankful to the support of the Chinese Academy of Sciences President’s International Fellowship Initiative(PIFI)Yunnan Provincial Council of Academicians and Experts Workstations(202405AF140006)Yunnan Provincial Department of Human Resources and Social Security(202505AO120004).
文摘Microcystins(MCs)are one of the most prevalent cyanotoxins and pose significant risks to aquatic ecosystems and human health,particularly in lakes used as drinking water sources.However,knowledge about the MC concentrations in plateau lakes experiencing high solar radiation is scarce.This study investigated the spatial-temporal distribution of MCs in eight Yunnan Plateau lakes in China,focusing on their relationships with environmental factors.Water samples(n=63)were collected during summer and winter seasons and analyzed for MC concentrations along with a suite of environmental variables.Results revealed significant seasonal and spatial variations in MC concentrations,with higher levels in eutrophic lakes Dianchi,Erhai,and Xingyunhu.Notably,mean MC concentrations in Lake Dianchi during summer and Erhai during winter exceeded the World Health Organization’s provisional guideline of 1μg/L for drinking water.Seasonal analyses revealed distinct regulatory mechanisms:MC concentrations in summer were positively correlated with total phosphorus,total nitrogen,turbidity,and chlorophyll a,reflecting the influence of eutrophication on cyanobacterial growth.While solar radiation intensity(SRI)exhibited a dual role:moderate SRI in winter was associated with higher MC levels,whereas higher SRI in summer suppressed MC production,likely due to photoinhibition or MC degradation.Strikingly,water temperature showed no significant correlation with MC concentrations,suggesting that high solar radiation in the Yunnan Plateau may override temperature-dependent effects on cyanobacterial growth.These findings highlight the importance of nutrient management and the regulatory role of solar radiation in regulating MC production in high-altitude lakes.The study underscores the need for region-specific strategies to mitigate cyanobacterial risks,particularly in drinking water source lakes,by integrating nutrient control and the unique light regime of plateau ecosystems.
文摘AIM To analyse clinical and dosimetric results of helical tomotherapy(HT)and volumetric modulated arc therapy(VMAT)in complex adjuvant breast and nodes irradiation.METHODS Seventy-three patients were included(31 HT and 42 VMAT).Dose were 63.8 Gy(HT)and 63.2 Gy(VMAT)in the tumour bed,52.2 Gy in the breast,50.4 Gy in supraclavicular nodes(SCN)and internal mammary chain(IMC)with HT and 52.2 Gy and 49.3 Gy in IMC and SCN with VMAT in 29 fractions.Margins to particle tracking velocimetry were greater in the VMAT cohort(7 mm vs 5 mm).RESULTS For the HT cohort,the coverage of clinical target volumes was as follows:Tumour bed:99.4%±2.4%;breast:98.4%±4.3%;SCN:99.5%±1.2%;IMC:96.5%±13.9%.For the VMAT cohort,the coverage was as follows:Tumour bed:99.7%±0.5%,breast:99.3%±0.7%;SCN:99.6%±1.4%;IMC:99.3%±3%.For ipsilateral lung,Dmean and V20 were 13.6±1.2 Gy,21.1%±5%(HT)and 13.6±1.4 Gy,20.1%±3.2%(VMAT).Dmean and V30 of the heart were 7.4±1.4 Gy,1%±1%(HT)and 10.3±4.2 Gy,2.5%±3.9%(VMAT).For controlateral breast Dmean was 3.6±0.2 Gy(HT)and 4.6±0.9 Gy(VMAT).Acute skin toxicity grade 3 was 5%in the two cohorts.CONCLUSION HT and VMAT in complex adjuvant breast irradiation allow a good coverage of target volumes with an acceptable acute tolerance.A longer follow-up is needed to assess the impact of low doses to healthy tissues.
基金This work was supported by the National Key R&D Programof China(Grant No.2016YFC0801204)the National Programon Key Basic Research Project of China(973 Program,Grant No.613312).
文摘Impact flash occurs when objects collide at supersonic speeds and can be used for real-time damage assessment when weapons rely on kinetic energy to destroy targets.However,the mechanism of impact flash remains unclear.A series of impact flash experiments of flat-head long-rod projectiles impacting thin target plates were performed with a two-stage light gas gun.The impact flash spectra for 6061 aluminum at 1.3e3.2 km/s collision speeds were recorded with a high-speed camera,a photoelectric sensor,and a time-resolved spectrometer.The intensity of the impact flash exhibited a pulse characteristic with time.The intensity(I)increased with impact velocity(V0)according to IfVn 0,where n?4.41 for V0>2 km/s.However,for V0<2 km/s,n?2.21,and the intense flash duration is an order of magnitude less than that of higher V0.When V0>2 km/s,a continuous spectrum(thermal radiation background)was observed and increased in intensity with V0.However,for V0<2 km/s,only atomic line spectra were detected.There was no aluminum spectral lines for V0<2 km/s,which indicated that it had not been vaporized.The initial intense flash was emission from excited and ionized ambient gases near the impact surface,and had little relationship with shock temperature rise,indicating a new mechanism of impact flash.
基金Supported by the National Natural Science Foundation of China (61233004, 61074061)the State Key Development Program for Basic Research of China (2013CB035500)+1 种基金the National High Technology Research and Development Program of China(2011AA040901)Key Project of Ministry of Railways of China (J2011J004)
文摘This paper mainly aims at the modeling problem of the photovoltaic (PV) array with a 30 kW PV grid-connected generation system. An iterative method for the time-varying parameters is proposed to model a plant of PV array. The relationship of PV cell and PV array is obtained and the solution for PV array model is unique. The PV grid-connected generation system is used to demonstrate the effectiveness of the proposed method by comparing the calculated values with the actual output of the system.
文摘In order to explore a dose distribution verification procedure of intensity modulated radiation therapy （IMRT） for nasopharyngeal carcinoma （NPC） and establish its evaluation criteria, we performed 35 two-dimensional （2D） patient-specific IMRT verifications over the year i006. The percent of pixels passing 7 and the normalized agreement test （NAT） index were mainly used to represent the agreement between the measured and computed dose distributions with three criteria （2%/2 mm, 3%/3 mm and 5%/3 mm） as recommended in the literature. The results were that all cases passed through verifications with three criteria except that the NAT index of one case was beyond the limitation, and the three tolerance levels of 2%/2mm, 3%/3 mm and 5%/3 mm produced similar clinical verification results but led to different percent of pixels passing Y and NAT index. Our data showed that the percent of pixels passing y and the NAT index were complementary to evaluate future IMRT verifications as two significant metrics. Due to the influence of the noise and the trait of the software, we considered an IMRT plan as acceptable in case of the percent ofpixels passing y 〉95% and the NAT index 〈5 with the 5%/3 mm criteria for IMRT patient-specific quality assurance （QA）.
基金support from the National Natural Science Foundation of China (Grant No.51606158,11604311,12074151)the Guangxi Science and Technology Base and Talent Special Project (Grant No.AD21075009)+6 种基金the Sichuan Science and Technology Program (Grant No.2021JDRC0022)the Natural Science Foundation of Fujian Province (Grant No.2021J05202)the Research Project of Fashu Foundation (Grant No.MFK23006)the Open Fund of the Key Laboratory for Metallurgical Equipment and Control Technology of Ministry of Education in Wuhan University of Science and Technology,China (Grant No.MECOF2022B01MECOF2023B04)the Project supported by Guangxi Key Laboratory of Precision Navigation Technology and Application,Guilin University of Electronic Technology (Grant No.DH202321)the Scientific Research Project of Huzhou College (Grant No.2022HXKM07)。
文摘Solar energy has always been a kind of energy with large reserves and wide application.It is well utilized through solar absorbers.In our study,the finite difference time domain method(FDTD)is used to simulate the absorber composed of refractory metal materials,and its absorption performance and thermal emission performance are obtained.The ultra-wide band of 200 nm-3000 nm reaches 95.93%absorption efficiency,of which the bandwidth absorption efficiency of2533 nm(200 nm-2733 nm)is greater than 90%.The absorption efficiency in the whole spectrum range(200 nm-2733 nm)is 97.17%on average.The multilayer nanodisk structure of the absorber allows it to undergo strong surface plasmon resonance and near-field coupling when irradiated by incident light.The thermal emission performance of the absorber enables it to also be applied to the thermal emitter.The thermal emission efficiency of 95.37%can be achieved at a high temperature of up to 1500 K.Moreover,the changes of polarization and incident angle do not cause significant changes in absorption.Under the gradual change of polarization angle(0°-90°),the absorption spectrum maintains a high degree of consistency.As the incident angle increases from 0°to 60°,there is still 85%absorption efficiency.The high absorption efficiency and excellent thermal radiation intensity of ultra-wideband enable it to be deeply used in energy absorption and conversion applications.
文摘To study the properties of a new surface-type infrared decoy,the numerical dispersion model and the infrared radiance model of the plates are established. In addition,the temperature of a single plate was measured during combustion experiment,and the spatial position and infrared radiance of each plate are calculated in plate cloud by the two models respectively. Furthermore,the radar images of the plate cloud are simulated and analyzed in dependence of time and direction for single and multiple launching. The result shows that the surface-type infrared decoy can be a point source of interference when the missile is remote tracking. In the meanwhile,the plates cloud shelters the infrared characteristics of the plume and jets of aircraft when the missile is on IR imaging guidance mode. Moreover,With the analysis of the plate cloud dispersion at different intervals and the infrared radiation intensity in the case of different launching number,it can be concluded that a comfortable launching interval can maintain a continuous plate cloud,launching the decoys simultaneously increase the increment of the radiation intensity obviously,the multiple launching is an effective way to enhance the interference property of the decoy.
文摘Chondrosarcomas are malignant bone tumors which develop as a cartilaginous differentiation of primary mesenchymal cells and the second most frequently seen malignant tumor of the bone after osteosarcoma. These malignancies are slowly growing non-epithelial tumors with unknown etiology and most frequently seen during the 4 decades of life. They are frequently localized on pelvis, ribs and long bones. Nasal septum CSs are very rarely seen malignancies. They originate from septal mucosa or cartilage and it is difficult to make a diagnosis unless they reach a certain size. A few cases of CSs with nasal septum have been reported in the literature. In cases of CSs, surgery is the gold standard treatment modality;however in surgically unresectable cases or close to margins, radiotherapy plays a significant role in primary and adjuvant treatment. Based on the position of the tumor in head and neck and extremely closeness of the tumor to vital organs as optic nerve, chiasm and brain, image guided-intensity modulated radiation therapy (IG-IMRT) becomes very effective and reliable modalities and may be a favorable treatment alternative.
基金This project is supported by National Natural Science Foundation of China(No.50175081).
文摘Based on the analysis of heat radiation intensity from flame, a new mathematical model ofthe tube-wall temperatmp of heated tubes is developed by taking down-fired, upright-tube cylindricalfurnace for example. The proposed mathematical model can be employed to indicate both the positionand size of the hot spot at fire-facing wall of heated tube of combustion chamber, and is characteristicof simplicity and efficiency If coupled with thermoelectric couple or infrared viewer, the presentedlocation method of combustion hot spot can offer engineers very valuable proposal to keep furnacerunning more safely The same is true for any other type of tubular furnaces.
基金the National Natural Science Foundation of China(Grant Nos.11774430,12075157,11775202,and 12175310)the Scientific Research Foundation of Hunan Provincial Education Department(Grant No.20A042).
文摘Low-noise terahertz(THz)radiation over 100 MV/cm generation by a linearly-polarized relativistic laser pulse interacting with a near-critical-density(NCD)plasma slab is studied by theory and particle-in-cell(PIC)simulations.A theoretical model is established to examine the dipole-like radiation emission.The THz radiation is attributed to the singlecycle low-frequency surface current,which is longitudinally constrained by the quasi-equilibrium established by the laser ponderomotive force and the ponderomotively induced electrostatic force.Through theoretical analysis,the spatiotemporal characteristics,polarization property of the THz radiation,and the relation between the radiation strength with the initial parameters of driving laser and plasma are obtained,which are in good consistence with the PIC simulation results.Furthermore,it is found by PIC simulations that the generation of thermal electrons can be suppressed within the appropriate parameter regime,resulting in a clear THz radiation waveform.The appropriate parameter region is given for generating a low-noise intense THz radiation with peak strength reaching 100 MV/cm,which could find potential applications in nonlinear THz physics.
