Establishing a mechanism for international cooperation for Fukushima nuclear-contaminated water monitoring

The Japanese government’s unilateral decision to discharge the nuclear-contaminated water from the Fukushima nuclear power plant into the ocean has caused immense nuclear safety risks.Monitoring the unclear contaminated water is a starting point to combat these risks and seek remedies for the rights and interests of all concerned parties.The establishment of a mechanism for international cooperation in this respect is necessary to handle the risks of the Fukushima nuclear-contaminated water and to lay the foundation of a framework for tackling any future disposal of nuclear-contaminated water following Japan’s example.At present,the international legal systems in the spheres of nuclear safety and security,marine environmental protection,and other areas,as well as the questioning of the monitoring reports of the International Atomic Energy Agency(IAEA)by the relevant parties,the monitoring practices of historical nuclear accidents,and numerous radioactivity monitoring mechanisms have provided the institutional and practical basis for constructing such a mechanism.The mechanism can be promoted by the IAEA through its existing mechanisms or be jointly initiated by China,the Russian Federation,the Republic of Korea,the Democratic People’s Republic of Korea,and the Pacific Island countries,among other stakeholders.Specifically,this mechanism should consist of three levels:first,the framework of the basic legal system,including the cooperative principles of national sovereignty,interest-relatedness,and procedural fairness,and the signing of the Framework Convention on the Monitoring of Fukushima’s nuclear-contaminated water and its Optional Protocol;second,the organizational structure and its responsibilities,which may include the Conference of Parties as the decision-making body,the Secretariat as the central coordinating body,and the monitoring committees in various fields as specific implementing agencies;and third,specific administrative arrangements,which involve the standardization of monitoring,the management system of monitoring networks and stations,the rules for monitoring procedures,and the rules for the utilization of the monitoring data,etc.With the urgent need for the scientific and fair monitoring of Fukushima’s nuclear-contaminated water,China,as a stakeholder country,can promote the establishment of such a mechanism for monitoring nuclear-contaminated water through the following paths:①It is necessary to clarify the factors affecting the construction of an international cooperation mechanism for monitoring nuclear-contaminated water so as to ascertain the standpoints of the stakeholders,claims of their interests,contents of their cooperation,and the relevant international relations.②On the basis of existing practices,China should consider improving the monitoring mechanism to cope with the risks of the discharge of Fukushima’s nuclear-contaminated water by formulating targeted policies and systems,setting up specialized monitoring institutions,and establishing a systematic monitoring network system.③This is an effective way for China to actively promote the participation of stakeholders in the construction of an international cooperation mechanism for monitoring nuclear-contaminated water in Fukushima by further innovating the dissemination mechanism to address the risk of Fukushima’s nuclear-contaminated water discharging into the sea and facilitating the identification of issues for international cooperation in monitoring Fukushima’s nuclear-contaminated water based on the concept of a community with a shared future for mankind.

DPRK Nuclear Issue:Non-proliferation or Strategic Game?

Out of concern over nuclear weapons proliferation,the worry over DPRK nuclear testing is overwrought.The author sees the situation from the viewpoint of a geopolitical game in a non-proliferation mask.To attempt a geopolitical game using non-proliferation is wrongly directed,but this is the main reason the issue fluctuates and deadlocks occasionally.To solve the situation once and for all,the international community needs to recognize its geopolitical nature and cure the problem accordingly.Since DPRK leader Kim Jong-Un crossed the border April 27 to meet South Korean President Moon Jae-in,the destiny of the Korean Peninsula is,as it should be,in the hands of the Koreans,not Chinese or Americans.

Mechanism of Hetero-nuclear β-type Chelates Formed by Rare Earths with p-sulphoaminobromophosphonazo

The reaction behavior of forming the hetero-nuclear β-type chelates of rare earth ions (RE 3+) with p-sulphoaminobromophosphonazo(BPA-pSN) in ClCH_2COOH-CH_3COONa buffer solutions were studied by a spectrophotometric method. The interaction of RE 3+ with BPA-pSN, which can forms hetero-nuclear β-type chelates having composition ratio of RE_1 (light rare earth):BPA-pSN:RE_2(heavy rare earth ion)=1∶3∶1, is a first-order reaction. Meanwhile, BPA-pSN can only forms homo-nuclear β-type chelates with heavy rare earth ions, having a composition ratio of RE∶BPA-pSN=1∶2 and being a second-order reaction. The rate constants of forming homo-and hetero-nuclear β-type chelates were obtained and the mechanism of forming hetero-nuclear β-type chelates was proposed.

Hydration mechanism of a cementitious material prepared with Si-Mn slag

A cementitious material was prepared by mixing 80wt% Si-Mn slag powder, 10wt% lime, and 10wt% anhydrite. The compressive strength of mortar samples reaches 51.48 MPa after 28 d curing. The analyses of X-ray diffraction （XRD） and scanning electron microscopy （SEM） show that much ettringite is formed in the sample cured for 3 d, and C-S-H gel increases rapidly during subsequent curing. Nuclear magnetic resonance （NMR） analysis of 29Si and 27Al and infrared spectroscopy （IR） analysis show that aluminum decomposition from tetrahedral network of the slag glass and its subsequent migration and re-combination play an important role in the process of hydration and strength development of the samples.

An Anisotropic Geomechanical Model for Jointed Rock Masses at Taishan Nuclear Power Station, Southern China

An anisotropic geomechanical model for jointed rock mass is presented. Simultaneously with deriving the orthotropic anisotropy elastic parameters along the positive axis, the equivalent compliance matrix for the deflection axis orthotropic anisotropy was derived through a three- dimensional coordinate transformation. In addition, Singh＇s analysis of the stress concentration effects of intermittent joints was adopted, based on two groups of intermittent joints and a set of cross- cutting joints in the jointed rock mass. The stress concentration effects caused by intermittent joints and the coupling effect of cross-cutting joints along the deflection-axis are also considered. The proposed anisotropic mechanics parameters method is applied to determine the deformation parameters of jointed granite at the Taishan Nuclear Power Station. Combined with the deterministic mechanical parameters of rock blocks and joints, the deformation parameters and their variability in jointed rock masses are estimated quantitatively. The computed results show that jointed granite at the Taishan Nuclear Power Station exhibits typical anisotropic mechanical characteristics; the elastic moduli in the two horizontal directions were similar, but the elastic modulus in the vertical direction was much greater. Jointed rock elastic moduli in the two horizontal and vertical directions were respectively about 24% and 37% of the core of rock, showing weakly orthotropic anisotropy; the ratio of elastic moduli in the vertical and horizontal directions was 1.53, clearly indicating the transversely isotropic rock mass mechanical characteristics. The method can be popularized to solve other rock mechanics problems in nuclear power engineering.

Mechanisms of repetitive transcranial magnetic stimulation for antidepression: Evidence from preclinical studies

This review summarizes the anti-depressant mechanisms of repetitive transcranial magnetic stimulation in preclinical studies,including anti-inflammatory effects mediated by activation of nuclear factor-E2-related factor 2 signaling pathway,anti-oxidative stress effects,enhancement of synaptic plasticity and neurogenesis via activation of the endocannabinoid system and brain derived neurotrophic factor signaling pathway,increasing the content of monoamine neurotransmitters via inhibition of Sirtuin 1/monoamine oxidase A signaling pathway,and reducing the activity of the hypothalamic-pituitary-adrenocortical axis.We also discuss the shortcomings of transcranial magnetic stimulation in preclinical studies such as inaccurate positioning,shallow depth of stimulation,and difficulty in elucidating the neural circuit mechanism up-and down-stream of the stimulation target brain region.

Structural Characteristics and Mechanical Properties of Rock Mass in the Field of Tianwan Nuclear Power Plant, China

The structural characteristics and mechanical properties of the rock mass are important parts of the feasibility study on the nuclear power engineering field. In this study, by means of in situ investigation and statistics, the structural plane and joint fissure features of the rock mass were analyzed and discussed at different plots and different depth scopes in the Tianwan Nuclear Power engineering field, the rock mass integrality and its weathered degree were evaluated respectively, and especially, the unfavorable geological phenomena of strongly-weathered cystid existing in the field were studied. According to the results of indoor rock mechanical tests, in combination with drilling, the shallow seismic prospecting, sonic logging and point load tests, the statistical results of physical and mechanical indices of rocks at key plots of the field were analyzed, and the design parameters of the field were calculated. It provided scientific basis for the foundation design of the nuclear power plant.

STUDIES ON COPOLYCONDENSATION MECHANISMS FROM m-METHOXY-p-ACETOXYBENZOIC ACID,p-ACETOXYBENZOIC ACID AND POLY(ETHYLENE TEREPHTHALATE)

Copolycondensation mechanisms for the terpolyester system from m-methoxy-p-acetoxybenzoic acid,p-acetoxybenzoic acid and poly(ethylene terephthalate)are first investigatedby high resolution proton NMR spectroscopy at 400 MHz.A series of reactivity ratios of thecopolycondensation reactions are given.The results shown that the m-methoxy-p-acetoxybenzoicacid tends to homopolymerize,while the p-acetoxybenzoic acid,and the ethylene terephthalate unitespecially,tend to copolymerize with the m-methoxy-p-acetoxybenzoic acid.

Progressive Thermalization Fusion Reactor Able to Produce Nuclear Fusions at Higher Mechanical Gain

In the standard fusion reactors, mainly tokamaks, the mechanical gain obtained is below 1. On the other hand, there are colliding beam fusion reactors, for which, the not neutral plasma and the space charge limit the number of fusions to a very small number. Consequently, the mechanical gain is extremely low. The proposed reactor is also a colliding beam fusion reactor, configured in Stellarator, using directed beams. D+/T+ ions are injected in opposition, with electrons, at high speeds, so as to form a neutral beam. All these particles turn in a magnetic loop in form of figure of “0” (“racetrack”). The plasma is initially non-thermal but, as expected, rapidly becomes thermal, so all states between non-thermal and thermal exist in this reactor. The main advantage of this reactor is that this plasma after having been brought up near to the optimum conditions for fusion (around 68 keV), is then maintained in this state, thanks to low energy non-thermal ions (≤15 keV). So the energetic cost is low and the mechanical gain (Q) is high (>>1). The goal of this article is to study a different type of fusion reactor, its advantages (no net plasma current inside this reactor, so no disruptive instabilities and consequently a continuous working, a relatively simple way to control the reactor thanks to the particles injectors), and its drawbacks, using a simulator tool. The finding results are valuable for possible future fusion reactors able to generate massive energy in a cleaner and safer way than fission reactors.

（N-Z） Odd-Even Effect for the Non-Equilibrium Mechanism of （p, n） Reactions

The neutron spectra and angular distributions from （p,n） reactions in the input proton energy range 6-25 MeV were analyzed. These are the old experimental data, however, re-analysis of these data reveals very interesting peculiarities which never have been discussed before. The high energetic part of neutron spectrum due to the direct mechanism changes considerably from one isotope to other. This difference was described with incorporation of two components which provide the ＂broad bump＂, or ＂step like＂ shape of neutron spectra at high energy. The properties of these components are： different shape, energy shift between them, and very strong fluctuation between different isotopes for ratio of cross sections connected with partial contribution. One may conclude that shape of non-compound neutron spectrum demonstrates very strong （N-Z） odd-even effect. The direct comparison of experimental data, and semi-empirical results with （p,n） spectra predicted by the EMPIRE code, gave evidence that the traditional approach cannot predict this effect. New finding may explain the ＂constant temperature＂ dependence for level density in mass range A-60 discussed in several investigations. These new experimental peculiarities were demonstrated, and it may be considered as reality. At the same time there is not consequent physical model for their explanation. The fact that spectrum shape is correlated with N-Z value may give a hint that discussed effects are connected with ＂halo-neutrons＂.

Study of Chemical Etching and Chemo-Mechanical Polishing on CdZnTe Nuclear Detectors

Cadmium zinc telluride (CdZnTe) semiconductor has applications in the detection of X-rays and gamma-rays at room temperature without having to use a cooling system. Chemical etching and chemo-mechanical polishing are processes used to smoothen CdZnTe wafer during detector device fabrication. These processes reduce surface damages left after polishing the wafers. In this paper, we compare the effects of etching and chemo-mechanical polishing on CdZnTe nuclear detectors, using a solution of hydrogen bromide in hydrogen peroxide and ethylene glycol mixture. X-ray photoelectron spectroscopy (XPS) was used to monitor TeO2 on the wafer surfaces. Current-voltage and detector-response measurements were made to study the electrical properties and energy resolution. XPS results showed that the chemical etching process resulted in the formation of more TeO2 on the detector surfaces compared to chemo-mechanical polishing. The electrical resistivity of the detector is of the order of 1010 Ω-cm. The chemo-mechanical polishing process increased the leakage current more that chemical etching. For freshly treated surfaces, the etching process is more detrimental to the energy resolution compared to chemo-mechanically polishing.

Elucidation of the hepatoprotective effect and mechanism of Melastoma dodecandrum Lour. based on network pharmacology and experimental validation

Objective:To systematically explore the effect and mechanism of melastomatis dodecandri herba(Melastoma dodecandrum Lour.)in the treatment of hepatitis based on network pharmacology.Method:We evaluated the hepatoprotective effects of M.dodecandrum in concanavalin A(Con A)-induced hepatitis in mice by assessing survival rate,histological analysis,serum transaminases,and related cytokines.Then the mechanism of action was predicted by a network pharmacology-based strategy.Based on the results,we measured the hepatic expression of related genes at mRNA level and proteins related to the phosphoinositide 3-kinase(PI3K)/protein kinase B(Akt)and nuclear factorkappa B(NF-кB)pathways.Results:Our study results clearly demonstrated that M.dodecandrum pretreatment significantly alleviated liver injury.This was demonstrated by an increase in survival rate,decreased severity of liver damage,and reduced serum transaminase levels compared with those in the Con A group.Moreover,M.dodecandrum significantly reduced the serum levels of tumor necrosis factor-a,interleukin-6,and interferon-g and increased the liver levels of superoxide dismutase,which indicated that M.dodecandrum exhibits anti-inflammatory and antioxidant activities.On the basis of network pharmacology,50 nodes were selected as major hubs based on their topological importance.Pathway enrichment analyses indicated that the putative targets of M.dodecandrum mostly participate in various pathways associated with the anti-inflammation response,which implies the underlying mechanism by which M.dodecandrum acts on hepatitis.Real-time fluorescent quantitative PCR analysis showed that M.dodecandrum downregulates the mRNA expression of interleukin-6,Toll-like receptor 7,interleukin-1 receptor-associated kinase-4,NF-кB and tumor necrosis factor-a in liver tissues.Western blotting showed that M.dodecandrum pretreatment protected against inflammation through activating the PI3K-Akt pathway by upregulating phosphorylated Akt(p-Akt)expression and suppressing NF-кB activation by inhibiting the phosphorylation of IKK,IkBa,and p65.Conclusion:The present work demonstrated the hepatoprotective effects of M.dodecandrum by regulating the PI3K/Akt and NF-кB pathways in Con A-induced mice,which provide insights into the treatment of hepatitis using M.dodecandrum.

Evaluation of combined detection of nuclear factor erythroid 2-related factor 2 and glutathione peroxidase 4 in primary hepatic carcinoma and preliminary exploration of pathogenesis

This study aims to analyze the clinical significance and mechanism of nuclear factor erythroid 2-related factor 2(NRF2)and glutathione peroxidase 4(GPX4)in primary hepatic carcinoma(PHC).Methods:The expression of NRF2 and GPX4 in peripheral blood of patients with PHC was determined to analyze the diagnostic value of the two combined for PHC.The prognostic significance of NRF2 and GPX4 was evaluated by 3-year followup.Human liver epithelial cells THLE-2 and human hepatocellular carcinoma cells HepG2 were purchased,and the expression of NRF2 and GPX4 in the cells was determined.NRF2 and GPX4 aberrant expression vectors were constructed and transfected into HepG2,and changes in cell proliferation and invasion capabilities were observed.Results:The expression of NRF2 and GPX4 in patients with PHC was higher than that in patients with LC or VH(p<0.05),and the two indicators combined was excellent in diagnosing PHC.Moreover,patients with high expression of NRF2 and GPX4 had a higher risk of death(p<0.05).In in vitro experiments,both NRF2 and GPX4 expression was elevated in HepG2(p<0.05).HepG2 activity was enhanced by increasing the expression of the two,vice versa(p<0.05).Conclusion:NRF2 and GPX4 combined is excellent in diagnosing PHC,and promotes the malignant development of PHC.

A method for 3D simulation of internal gas effects on thermal-mechanical behaviors in nuclear fuel elements

A new method for three-dimensional simulation of the interaction between the gas and the solid around is developed.The effects of the gas on the thermal-mechanical behaviors within the surrounded solid are performed by replacing the internal gas with an equivalent solid in the modeling,which can make it convenient to simulate the thermal-mechanical coupling effects in the solid research objects with gases in them.The applied thermal expansion coefficient,Young's modulus and Poisson's ratio of the equivalent solid material are derived.A series of tests have been conducted;and the proposed equivalent solid method to simulate the gas effects is validated.

冻融循环作用下不同含水率灰土的细微观结构与宏观力学性能

为了探明素土和灰土在不同含水率时细微观结构与宏观力学性能受冻融循环的影响规律,开展了素土和灰土在不同含水率时的冻融循环试验、抗压强度试验和核磁共振试验。结果表明,素土和灰土抗压强度均随含水率的提高而降低;素土和灰土抗压强度在同一含水率时均随着冻融循环次数的增加而降低,冻融循环六次时降低率可达到12次时的80%左右;灰土T_(2)谱信号峰值大于素土,T_(2)谱信号峰值随着灰土比例的提高而增大;不同含水率时素土和灰土T_(2)谱面积在冻融循环次数由3次增大至6次的增长率均明显大于6次至12次。

静水压作用下砂岩渗透特性及渗透率模型改进

为探究应力状态对西部弱胶结砂岩渗透率的影响规律,明晰开采过程中岩层的渗流、力学特性,分别开展静水压状态下的岩石渗流试验和核磁共振试验,在此基础上进行岩石渗透率的反演,分析渗透过程中岩石内部孔隙结构的变化规律,进而对核磁渗透率模型进行修正。结果表明:(1)围压对岩石渗透率影响显著,促使岩石内部孔隙结构发生改变,渗透压差的增大会造成岩石内部孔隙的扩张,渗流通道增多,渗透率增大;(2)围压增大导致的微、细孔隙的闭合存在一个极限值,微、细孔隙达到闭合极限所需的围压明显低于大孔隙,微、细孔隙对岩石渗透率的影响随围压的增大而逐渐降低,大孔隙闭合对岩石渗透率的下降贡献值最大;(3)围压的增大会导致岩石内部大孔转为微、细孔,T2截止值呈增加趋势,围压增大引起的孔隙结构的变化会导致岩石内部自由孔隙转化为束缚孔隙,从而造成渗透率的变化;(4)在考虑围压对孔隙结构变化的影响后,对核磁渗透率模型进行修正,修正后的渗透率模型能够较好地反演出岩石的渗透率,为该类岩石进行核磁试验渗透率反演提供了有效依据。

高空核爆炸晚期核电磁脉冲的数值模拟研究

根据高空核爆炸晚期核电磁脉冲(E3)的产生机理,将E3的计算分解为大气电离、碎片云运动、大气等离子体运动和低频电磁场在等离子体中的传播4个过程,给出了E3的数值模拟方法。利用该方法模拟了美国Starfish试验的E3过程,通过与试验观测地磁数据的比对验证了该方法的正确性。对离子的能量沉积分析结果表明,爆心正下方存在大气等离子体火球,能量峰值约为175 km,此火球向下膨胀导致地磁场增强,向上运动导致磁场变弱。该结果解释了Starfish试验地磁扰动波形的变化机理,与原有解释机理相比,无需引入额外的假设。

震动载荷多次作用下烟煤孔裂隙结构演化特征试验研究

煤层开采过程中频繁采掘扰动或远场顶板周期性破断会产生多次的震动载荷,震动载荷对于煤样微观孔裂隙结构和宏观力学行为具有重要影响。为探索震动载荷下煤样孔裂隙结构演化特征,选取烟煤煤样,利用霍普金森压杆(SHPB)试验系统开展了多次震动载荷冲击煤样试验,借助低场核磁共振分析仪测试了每次冲击后煤样T_(2)谱,并通过核磁共振成像(MRI)分析了煤样孔裂隙分布及其损伤演化特征。结果表明,随着震动载荷作用次数增加,煤样峰值应力与动态弹性模量均呈现线性下降趋势,震动载荷冲击效应使得煤样承载和抵抗变形能力显著弱化,因此有必要对煤样孔裂隙演化特征展开深入分析。从T_(2)谱和MRI信息得出,震动载荷初次作用下煤样总体孔隙体积大幅增加,其中吸附孔体积增高达5.0倍,随着震动载荷持续作用,煤样微裂隙开始连通汇聚形成宏观裂纹,使得渗流孔之间连通性大幅提高,煤样总体孔隙率达到峰值,较煤样原始孔隙率提高约6倍。在煤样受震动载荷损伤、破坏的整个过程中,渗流孔的连通性逐渐提高与改善,其分形维数呈线性下降趋势。通过核磁共振成像揭示了震动载荷对煤样孔裂隙作用机制,结果表明煤样中部区域孔隙最先发育并逐步形成微裂隙,在后续震动波反射、拉伸作用下,损伤破坏区域向两侧逐渐演变直至贯通试样。

姜黄素抑制NF-κB信号通路缓解氧化应激对成骨分化的损害发挥抗骨质疏松作用

目的 探讨姜黄素抑制氧化应激对成骨分化损害的机制及以剂量依赖的方式发挥抗骨质疏松的作用。方法 采用细胞氧化应激模型,加入不同浓度的姜黄素,测定骨形成指标,并检测参与的潜在信号通路。同时,用姜黄素处理小鼠去卵巢(ovariectomized, OVX)骨质疏松动物模型来证实其抗骨质疏松的作用。结果 体外实验发现,低浓度姜黄素(1~10μmol·L^(-1))促进成骨细胞增殖,提高骨形成碱性磷酸酶(alkaline phosphatase, ALP)活性,逆转氧化应激导致的成骨钙沉积下降,降低了核因子kappa-B配体的受体激动剂(RANKL)和白介素-6 (IL-6)的表达。体内实验结果显示,姜黄素(5 mg·kg^(-1))给药后部分逆转了OVX小鼠血液中丙二醛(malondialdehyde, MDA)和谷胱甘肽(glutathione, GSH)活性的比例、降低高骨代谢、增加骨密度(bone density, BMD)、改善了骨小梁的微结构,但高浓度姜黄素无氧化应激保护作用。结论 姜黄素可以减轻氧化应激的骨形成损害,NF-κB信号通路是主要参与通路,姜黄素可能是预防骨质疏松症的理想药物。