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.

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.

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.

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.

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.

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.

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.

Study on Mutagenic Effect of Cobalt-60 Irradiation on Potato

[Objective] This study aimed to investigate the mutagenic effect of cobalt- 60 irradiation on potato. [Method] Potato tubers of Favorita and Zhongshu No.3 were irradiated with 5, 10, 20, 30, 50 and 70 Gy of cobalt-60 γ-ray respectively, to explore the mutagenic effect of different doses of γ-ray heavy ion irradiation on potato. [Result] The results showed that the emergence rate, seedling rate, plant growth, yield and commodity of potato varied after irradiated with different doses of cobalt-60 γ-ray; 10Gy of cobalt-60 irradiation played a positive effect on the growth and development of potato, while high doses played a negative effect on the growth and development of potato. After cobalt-60 irradiation, the botanical traits of M1 gen- eration varied greatly, resulting in a number of beneficial mutation traits; some traits of M2 and M3 generations became stably inherited. [Conclusion] Cobalt-60 irradiation breeding is conducive to the variety improvement and germplasm innovation as an effective means of genetic improvement for potato.

SRAP Marker Analysis of Genomic Mutation Induced by ^(60)Coγ-Ray Irradiation in Potato (Solanum tuberosum)

[Objective] This study was to explore the mutagenic effect of 60Co γ-ray on Solanum tuberosum chromosomes.[Method] The 60Co γ-ray at different irradiation doses was applied to treat the minitubers of potato variety ＇Favorita＇,and the genomic mutations in VM1 and VM2 gene rations in treatments with different doses were analyzed by SRAP markers.[Resalt] Thirty pairs of SRAP primers out of 88 pairs exhibited polymorphism with a rate of 34.1％ in the bulked selection of VM1 generation.A total of 225 bands were obtained,of which 64 were polymorphic with a rate of 28.4％.The polymorphism was reflected in the forms of deleted bands and added bands.Based on the result of the bulked selection of VM1 generation,25 primers with polymorphism were selected to scan VM2 generation.Five primers performed poorly,and nine of the rest 20 pairs revealed polymorphism and obtained nine polymorphic bands,of which only four bands were detected in VM1 generation and the other five ones were newly deleted bands.Only 9.8％ of the bands detected in VM1 generation were obtained in VM2 generation.Eventually,nine stable and dear polymorphic bands were recovered and cloned,and DNA sequences of six bands of them were acquired by sequencing.According to the comparative analysis,five fragments sequences were similar to potato chromosome with a similarity rate of 77％-89％,three of them located at the resistance gene cluster; another one fragment had a similarity of 93％ with some regions of the No.5 chromosome in tomato.[Conclusion] 60Co γ-ray irradiation can cause mutation of genomic DNA in potato;there is no significant correlation between the number of polymorphic bands and the irradiation dose; potymorphic bands are characterized by a larger number of deleted bands than that of the added ones.

^(60)Co-γ射线对不同无花果品种一年生枝条的辐射效应分析

【目的】研究^(60)Co-γ射线对不同无花果品种一年生枝条死亡率、抗氧化酶活性等相关理化指标的影响,确定最佳辐射诱变剂量,为利用^(60)Co-γ射线辐射诱变技术提高无花果遗传多样性、创造新种质、培育优良新品种提供科学依据。【方法】以无花果品种布兰瑞克和中华紫果一年生休眠枝为试材,采用^(60)Co-γ射线为辐照源,设置不同剂量0、30、45、60、75 Gy的辐射处理,分析辐照引起枝叶死亡率、酶活性等变化。【结果】随着辐射剂量的增加,2个无花果品种扦插苗成活率呈下降趋势,株高、茎粗、节间长度、叶片长度、叶片宽度和分枝数指标呈下降趋势,叶片长宽比差异不显著。中华紫果品种的SOD、POD、CAT等酶活性均呈现先增后减的趋势,分别在45、60 Gy剂量时达到峰值,MDA含量呈现一直上升趋势,H_(2)O_(2)含量呈现先增后降趋势。布兰瑞克品种的SOD、POD、CAT酶活性,随着辐射剂量的增加均呈现先降后增趋势。MDA、H_(2)O_(2)含量基本保持上升趋势。【结论】辐射导致无花果扦插苗幼苗生长缓慢、株高矮化、茎粗变细、叶片变小、分枝减少。中华紫果的半致死辐射剂量为56 Gy,布兰瑞克为70 Gy,布兰瑞克对辐射的耐受性高于中华紫果。

平菇^(60)Co-γ诱变孢子杂交新种质的创制及其遗传多样性分析

为了探究不同平菇品种对辐射的敏感性及适宜辐射剂量,以便快速准确地鉴别平菇的杂交后代,创制新平菇种质,从而加快育种进程,本研究利用10个^(60)Co-γ射线剂量分别辐射4种不同平菇的孢子悬浮液,对致死率进行统计,并获得了诱变菌株的孢子单核体。随后配制杂交组合,开展了^(60)Co-γ诱变和杂交育种研究。基于简单序列重复(SSR)标记,对诱变后材料和杂交后代共39份材料进行了遗传多样性分析。结果表明,品种5178的适宜辐射剂量为500 Gy,时间为200 min;9408的适宜辐射剂量为600 Gy,时间为240 min;灰美2号的适宜辐射剂量为700 Gy,时间为280 min;榆黄菇T2的适宜辐射剂量为400 Gy,时间为160 min。筛选获得的35个长势良好的杂交子中,经SSR分子标记验证,这些菌株在8对引物扩增下呈现出不同的特异性条带。综上,本研究可快速、准确地鉴别杂交子,为平菇的辐射诱变和杂交育种提供了技术依据和理论参考。

含^(60)Co极低放土壤废物的填埋处置

在对四川省城市放射性废物库暂存的含^(60)Co极低放土壤废物进行源项分析的基础上确定了填埋处置方案。根据填埋处置方案对该批含^(60)Co极低放土壤废物进行了填埋,对填埋过程中工作人员受照剂量进行了估算。经计算,此次填埋操作过程中工作人员最大个人剂量为103.07μSv,满足相关剂量控制要求。

甘草查尔酮A对HL-60细胞恶性生物学行为的抑制作用及其机制

目的 探究甘草查尔酮A(LA)对急性髓系白血病(AML)细胞HL-60的作用及其机制。方法 将人AML细胞系HL-60细胞分为对照组、LA组(30μmol/L)、IL-6组(100 ng/mL,JAK2/STAT3信号通路激活剂)和LA+IL-6组。培养48 h后,采用MTT法和克隆形成实验检测HL-60细胞增殖活性;采用流式细胞术检测HL-60细胞周期分布和细胞凋亡;采用Transwell实验检测HL-60细胞侵袭和迁移;采用Western blot检测p21、p27、cyclin E2、CDK2、Bcl-2、Bax、cleaved-Caspase-3、p-JAK2,JAK2,p-STAT3和STAT3蛋白表达水平。结果 与对照组比较,LA组细胞活力、克隆形成数、侵袭和迁移细胞数均降低(P<0.05),Bcl-2、cyclin E2和CDK2蛋白表达量均降低(P<0.05),JAK2和STAT3蛋白的磷酸化水平均降低(P<0.05);G0/G1期细胞比例和细胞凋亡率均升高(P<0.05),p21、p27、Bax和cleaved Caspase-3蛋白表达量均升高(P<0.05)。与对照组比较,IL-6组细胞活力、克隆形成数、侵袭和迁移细胞数均升高(P<0.05),Bcl-2、cyclin E2和CDK2蛋白表达量均升高(P<0.05),JAK2和STAT3蛋白的磷酸化水平均升高(P<0.05),G0/G1期细胞比例和细胞凋亡率均降低(P<0.05),p21、p27、Bax和cleaved Caspase-3蛋白表达量均降低(P<0.05)。与IL-6组比较,LA+IL-6组细胞活力、克隆形成数、侵袭和迁移细胞数均降低(P<0.05),Bcl-2、cyclin E2和CDK2蛋白表达量均降低(P<0.05),JAK2和STAT3蛋白的磷酸化水平均降低(P<0.05),G0/G1期细胞比例和细胞凋亡率均升高(P<0.05),p21、p27、Bax和cleaved-Caspase-3蛋白表达量均升高(P<0.05)。LA+IL-6组和LA组间上述指标差异没有统计学意义。结论 甘草查尔酮A可抑制AML细胞系HL-60细胞增殖、侵袭和迁移,诱导细胞凋亡并将细胞阻滞在G0/G1期,其作用机制可能与抑制JAK2/STAT3信号通路激活有关。

Enhanced Enzymatic Hydrolysis of Miscanthus sinensis Following Synergic Pretreatment with ^(60)Co γ-ray Irradiation and Alkaline Hydrogen Peroxide

[Objective] This study aimed to investigate the effects of different pretreat- ments on enzymatic saccharification of Miscanthus sinensis and improve reducing sugar yield in the enzymolysis process. [Method] M. sinensis was pretreated with 60Co y-ray irradiation and alkaline hydrogen peroxide, to analyze their effects on re- ducing sugar yield of enzymatic hydrolysis. [Result] After pretreatment with 400 kGy 60Co y-ray irradiation, reducing sugar yield in the enzymolysis process of M sinensis was 76.24 mg/g; after synergic pretreatment with 400 kGy 60Co y-ray irradiation and alkaline hydrogen peroxide, reducing sugar yield in the enzymolysis process of M. sinensis was 505.08 mg/g, which was improved by 5.6 times compared to that in pretreatment with 400 kGy 60Co y-ray irradiation. Based on process optimization, the optimal hydrolysis conditions were obtained： pretreatment temperature 30 ℃, NaOH concentration 1.2%, hydrogen peroxide concentration 2%, pretreatment time 6 h. [Conclusion] Synergic pretreatment with 60Co y-ray irradiation and alkaline hydrogen peroxide could significantly improve reducing sugar yield in the enzymolysis process of M. sinensis, which provided a new theoretical basis for preparing fuel ethanol with M. sinensis.

Investigation on the Appropriate Dose of ^(60)Co-γ Irradiation for Tubers of Purple Sweet Potato

[Objective] This study aimed to investigate the appropriate dose of 60^Co-γ irradiation for tubers of purple sweet potato.[Methods] The tubers of two purple sweet potato varieties Xuzi L-7 and Yuenanzi were used as experimental materials,and treated with 60^Co-γ irradiation at different doses（0,25,50,75,100,125 and 150 Gy） to determine the emergence rate,number of emerged seedlings per tuber and fresh weight per seedling.[Results] After the 60^Co-γ irradiation at different doses,the emergence period of tubers was postponed while the emergence rate,number of emerged seedlings per tuber and fresh weight per plant were decreased,and the differences between different varieties and different irradiation doses reached significance level.Compared with the control,the emergence period of tubers at irradiation doses above 25 Gy were postponed by 2,3,5,6 and 12 d,respectively.[Conclusion] The half lethal dose（LD50） of Xuzi L-7 was 66.73 Gy,and that of Yuenanzi was 74.96 Gy.

近60 a中国极端天气气候事件变化趋势及2023年特征分析

对不同区域极端天气气候事件变化规律的研究,有助于提高我国防灾减灾能力和有效应对气候变化风险。利用我国均一化的2254个气象观测站逐日观测资料,分析评估近60 a和2023年我国及其各区域(未包含港澳台地区)发生的极端高温、极端低温、极端干旱、极端降水和极端台风等极端天气气候事件(简称“极端事件”)的时空特征。结果表明,1961年以来,我国极端事件总体呈下降趋势,其中1970—1990年代初下降趋势明显,1990年代后期以来增加趋势明显;极端高温事件呈显著增加趋势,进入21世纪后增加趋势更加明显;极端低温事件呈减少趋势;极端降水事件总体呈增加趋势;极端干旱事件呈下降趋势且阶段性特征明显;近60 a来受台风影响出现的极端风速和降水事件呈减少趋势,主要由极端台风风速事件减少造成,而极端台风降水事件呈缓慢上升趋势。2023年我国极端事件每站平均发生139次,比气候平均值偏多28.3%。其中,极端高温事件平均发生79次(偏多76.8%),为1961年以来历史最多年;极端低温事件平均发生20次(偏少23.8%);极端降水事件平均发生14次,极端干旱事件平均发生26次,都接近常年平均值;极端台风事件平均发生0.41次(偏多4.2%),主要以极端台风降水事件为主。2023年极端事件主要出现在西南地区、江南西部、华南西部、西北地区中部和北部、内蒙西部、京津冀等地,其中四川东部、贵州南部、甘肃西部、内蒙西部等地超过200次。极端事件增多的主要原因是极端高温事件和极端干旱事件增多。综合等级指数分析表明,极端事件高危险区域主要位于南方地区,特别是东南沿海地区,近60 a综合等级指数增加的区域主要位于西南地区到东北地区南部这个过渡带上。2023年高危险区域主要出现在西南地区和西北地区中北部。