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Kr离子注入SiC的拉曼光谱研究
No full text<span id="ChDivSummary" name="ChDivSummary">应用拉曼光谱研究了5 MeV Kr离子(注量分别为5×1013,2×1014,1×1015ions/cm2)室温注入6 H-SiC单晶及其高温退火处理后结构的变化。研究表明,注入样品的拉曼光谱中不仅出现了Si—C振动的散射峰,还产生了同核Si—Si键和C—C键散射峰。Si—C散射峰强度随退火温度升高而增强,当退火温度高达1000℃时,已接近未辐照SiC的散射峰强度。晶体Si—Si键散射峰强度随退火温度变化不大,而非晶Si—Si键散射峰强度随退火温度的增加逐渐消失。相对拉曼强度(Relative Raman Intensity,简称RRI)随注量的增加逐渐减小并趋于饱和,且不同退火温度样品的饱和注量不相同;RRI随退火温度的增加逐渐升高,这在低注量样品中表现得尤为明显。低、中、高3种注量样品的RRI随退火温度的增加从重合逐渐分离,并且退火温度越高,分离越大。 </span><a id="ChDivSummaryMore" style="DISPLAY: none">更多</a>国家自然科学基金资助项目(10575124,10979063
High LET Radiation Enhances Nocodazole Induced Cell Death in HeLa Cells through Mitotic Catastrophe and Apoptosis
No full textTo understand how human tumor cells respond to the combined treatment with nocodazole and high LET radiation, alterations in cell cycle, mitotic disturbances and cell death were investigated in the present study. Human cervix carcinoma HeLa cells were exposed to nocodazole for 18 h immediately followed by high LET iron ion irradiation and displayed a sequence of events leading to DNA damages, mitotic aberrations, interphase restitution and endocycle as well as cell death. A prolonged mitotic arrest more than 10 h was observed following nocodazole exposure, no matter the irradiation was present or not. The occurrence of mitotic slippage following the mitotic arrest was only drug-dependent and the irradiation did not accelerate it. The amount of polyploidy cells was increased following mitotic slippage. No detectable G(2) or G(1) arrest was observed in cells upon the combined treatment and the cells reentered the cell cycle still harboring unrepaired cellular damages. This premature entry caused an increase of multipolar mitotic spindles and amplification of centrosomes, which gave rise to lagging chromosomal material, failure of cytokinesis and polyploidization. These mitotic disturbances and their outcomes confirmed the incidence of mitotic catastrophe and delayed apoptotic features displayed by TUNEL method after the combined treatment. These results suggest that the addition of high-LET iron ion irradiation to nocodazole enhanced mitotic catastrophe and delayed apoptosis in HeLa cells. These might be important cell death mechanisms involved in tumor cells in response to the treatment of antimitotic drug combined with high LET radiation
Radiosensitization by Inhibiting Survivin in Human Hepatoma HepG2 Cells to High-LET Radiation
No full textIn this study, whether survivin plays a direct role in mediating high-LET radiation resistance in human hepatoma cells was investigated. Small interfering RNA (siRNA) targeting survivin mRNA was designed and transfected into human hepatoma HepG2 cells. Real-time PCR and western blotting analyses revealed that survivin expression in HepG2 cells decreased at both transcriptional and post-transcriptional levels after treatment with survivin-specific siRNA. Caspase-3 activity was determined with a microplate reader assay as well. Following exposure to high-LET carbon ions, a reduced clonogenic survival effect, increased apoptotic rates and caspase-3 activity were observed in the cells treated with the siRNA compared to those untreated with the siRNA. The cells with transfection of the survivin-specific siRNA also increased the level of G(2)/M arrest. These results suggest that survivin definitely plays a role in mediating the resistance of HepG2 cells to high-LET radiation and depressing survivin expression might be useful to improve the therapeutic efficacy of heavy ions for radioresistant solid tumors
高精度三组合四极透镜
No full text<p align="left"><font face="宋体" size="3">实用新型涉及加速器束流输运线电磁铁系统的机械设计制造技术领域，尤其是涉及一种高精度三组合四极透镜。其包括组合体外围框架，高精度四极透镜通过连接杆和不锈钢块安装在组合体外围框架内，高精度四极透镜内设有磁铁线圈，高精度四极透镜下部设有与磁铁线圈相连的电联结板，组合体外围框架上部设有直线导轨座、滚动导轨座和移动板，直线导轨座上设有直线导轨，滚动导轨座上设有滚动导轨。其通过采用了全新的设计思路和机械结构，选取合理的工艺及制造手段，实现物理实验对工程制造的高要求。为研究所和企业制造高精度的四极透镜提供了具体的方案和经验。能够达到微米级的安装精度，以及实验所需的稳定性。</font></p
甜高粱汁液的生物储存方法
No full text<p><font face="宋体" size="3">发明提供了一种甜高粱汁液的生物贮存方法，是将新压榨的甜高粱汁液送入密闭贮罐，调整pH值至4.5～6.5，泵入灭菌罐，于温度60～90℃下蒸汽灭菌30～60分钟；然后冷却至10～25℃，除去沉淀，加入汁液质量0.01％～0.1％的酶搅拌均匀，立即泵入带有单向呼吸阀的密闭贮罐贮存。本发明利用微生物低温生长缓慢、向单一方向代谢的过程，竞争性抑制其它微生物的生长繁殖，从而达到保护汁液不变质的目的。实验证明，甜高粱汁液通过本发明生物贮存，三个月不变质。</font></p
一种利用高能粒子束辐照时减小离子束展宽bragg峰后沿计量半影的方法
No full text<p><font face="宋体" size="3">发明涉及一种利用高能离子束辐照减小离子束展宽Bragg峰后沿剂量半影的方法。脊形过滤器垂直放置于束流扫描二级磁铁、离子探测器、射程移位器间的束流轴线中，并离子探测器与置于射程移位器之间，由束流扫描二级磁铁形成均匀照射野的离子束通过微型脊形过滤器进行照射，其步骤是先采用微型脊形过滤器FWHM1对所需SOBP的深处进行照射，然后以微型脊形过滤器FWHM2替换微型脊形过滤器FWHM1对SOBP的其他部分进行照射。本发明可充分发挥离子束辐照时能量沉积局域性的优势，在实施三维适形照射时既可减小离子束Bragg峰后沿的剂量半影，同时又减少了照射时间，在进行离子束辐照材料改性、辐照育种和放射治疗等离子束辐照技术中具有广泛的应用价值。</font></p
藏茵陈饮片的制备方法
No full text<p><font face="宋体" size="3">发明属医药技术领域，本发明公开了一种藏茵陈饮片的制备方法。该方法包括以下步骤：先将藏茵陈经过紫外照射消毒，同时将黑曲霉依序经过麦芽浸粉斜面培养、种子培养基扩大培养和发酵培养基发酵培养后，将发酵物烘干、粉碎，定量装入胶囊或制成片剂。本发明所采用的方法主要是通过黑曲霉产生的纤维素分解酶、半纤维素分解酶破坏植物药细胞壁结构，从而有利于藏茵陈中有效成分的消化吸收。该方法具有操作简单，成本低廉，资源利用率高的优点，易于进行工业化生产，具有很高的实际应用价值，市场前景广阔。此外，本方法对于其他中药饮片的制备同样具有借鉴意义。</font></p
Mechanical properties and defects evolution of inert-gases ion implanted 6H-SiC
No full text<span style="font-family: 'Microsoft Yahei', 宋体, Arial, ' Helvetica', ' sans-serif'; font-size: 13px; line-height: 22px;">本论文利用多种分析手段，研究了惰性气体离子辐照在碳化硅材料中导致的辐照损伤、微观结构以及材料力学性能的变化规律。分别选用能量为5 MeV的氪（Kr）离子与2.3 MeV的氖（Ne）离子辐照6H-SiC单晶样品（室温辐照），注量分别为5x1013, 2x1014, 1x1015 Kr19+ ions/cm2与2x1014, 1.1x1015, 3.75x1015 Ne8+ ions/cm2。注入完成后分别在室温，500，700和1000 ℃温度下真空退火。随后采用纳米压痕仪，高分辨XRD，原子力显微镜，拉曼光谱等多种手段对样品进行分析测试。 纳米压痕实验研究表明：离子注入导致样品硬度值发生变化，且注入样品的硬度值与注量紧密相关。Kr离子注入样品退火后发现，不同注量样品的最大硬度出现在不同的退火温度；但不同注量的Ne离子注入样品退火后的最大硬度值皆出现在700 ℃。这些现象都与样品中化学键密度变化、缺陷的产生及其演化过程密切相关。 高分辨XRD研究表明：材料中的应变量随注量的增加而增大。退火过程中应变的变化规律与退火温度和注量紧密相关；除2x1014 Kr/cm2样品在700℃退火时应变突然增加外，其余注量的Kr注入样品和Ne注入样品的应变随退火温度的增加逐渐降低。应变在不同温度的变化对应着不同类别的缺陷演化过程。 AFM扫描发现，压痕印记尖端裂纹只在未注入样品中和注入后退火样品中观察到；在注入样品中，裂纹长度随退火温度的增加逐渐伸长，且伸长量与注量相关。 氪离子注入样品的拉曼光谱研究表明，注入样品的拉曼光谱不仅出现了Si-C振动的散射峰，还产生了同核Si-Si键和C-C键散射峰。Si-C散射峰强度随退火温度升高而增强；晶体Si-Si键散射峰强度随退火温度变化不大，而非晶Si-Si键散射峰强度随退火温度的增加逐渐消失。相对拉曼强度随注量的增加逐渐减小并趋于饱和，且不同退火温度样品的饱和注量不相同。</span><span style="font-family: 'Microsoft Yahei', 宋体, Arial, ' Helvetica', ' sans-serif'; font-size: 13px; line-height: 22px;">This paper discusses the irradiation damage, micro-structure and the mechanical properties of 6H-SiC by multiple analysis tools. SiC was irradiated with 5 MeV krypton ion and 2.3 MeV neon ion at room temperature to the fluences of 5x1013, 2x1014, 1x1015 Kr ions/cm2 and 2x1014, 1.1x1015, 3.75x1015 Ne ions/cm2 and then anneal at room temperature, 500, 700 and 1000 oC in vacuum circumstance. Nanoindentation, high resolution XRD, AFM and Raman spectrum were carried out to study the the irradiation damage, micro-structure and the mechanical properties of 6H-SiC. Nanoindentation experiment shows that the hardness values of specimens are related to irradiation fluence. In specimens Kr-implanted, the maximum hardness values arising at different temperature for different irradiated fluences, whereas the hardness values of specimens Ne-implanted arise at 700 oC. All of the discussions above are connected with defects evolution. The results of high resolution XRD indicate that the strain increase with increase fluence. Strain alteration in specimens is a function of annealing temperature and irradiated fluence in annealing process. Except for the strain abrupt increasing at 700 oC in the specimen irradiated to fluence of 2x1014Kr/cm2, the strain values in other specimens implanted with Kr and Ne gradually decrease with increasing annealing temperature. Cracks were observed at the corners of nano-indenter imprints by atomic force microscopy (AFM) in virgin SiC and annealed specimen and crack length varies with implantation dose and annealing temperature. The Raman spectrum of implanted SiC displays not only Si-C bonds vibration peaks, but also homonuclear Si-Si and C-C bond vibration peaks. The Si-C bond vibration peaks gradually strengthen with increasing temperature. It is found that crystal Si-Si bond vibration peaks do not change when annealing, but amorphous Si-Si bond vibration peaks disappear with increasing temperature. Relative Raman Intensity (RRI) decreases versus increasing dose and trends to saturate, but the saturation dose is different for various anneal temperature.</span
High energy heavy ion microbeam irradiation facility at IMP
No full text<span style="color: rgb(46, 46, 46); font-family: Arial, Helvetica, "Lucida Sans Unicode", "Microsoft Sans Serif", "Segoe UI Symbol", STIXGeneral, "Cambria Math", "Arial Unicode MS", sans-serif; font-size: 16px; line-height: 18.944px; word-spacing: -1.32px;">A high energy heavy ion microbeam irradiation facility was designed and installed in the Institute of Modern Physics (IMP) of Chinese Academy of Sciences (CAS). It can deliver well-focused ions into the targets at exact locations. With the advantage of allowing vertical irradiation as well as focusing ions from Carbon to Uranium with high energies in a broad energy range (7 MeV/u to 100 MeV/u for Carbon ions), this setup is able to deliver a preset number of ions into pre-selected target positions. Material specimens in vacuum and living cells in air can also be irradiated by this facility. Detailed description of this microbeam facility as well as its beam optics is presented in this paper. Some preliminary test results are also given.</span
Preliminary design and simulation of a 162.5 MHz high-intensity proton RFQ for an accelerator driven system
No full text<span style="color: rgb(51, 51, 51); font-family: arial, helvetica, sans-serif; font-size: 13px; line-height: 22px; background-color: rgb(248, 248, 248);">A new procedure for the design and simulation of a Radio Frequency Quadrupole (RFQ) accelerator has been developed at the Argonne National Laboratory. This procedure is integrated with the beam dynamics design code DESRFQ and the simulation code TRACK, which are based on three-dimensional field calculations and the particle-in-cell mode beam dynamics simulations. This procedure has been applied to the development of a 162.5 MHz CW RFQ which is capable of delivering a 10 mA proton beam for the Accelerator Driven System (ADS) of the CAS. The simulation results show that this RFQ structure is characterized by the stable values of the beam acceleration efficiency for both the zero current beam and space charge dominated beam. For an average beam current of 10 mA, there is no transverse rms emittance growth, the longitudinal rms emittance at the exit of RFQ is low enough and there is no halo formation. The beam accelerated in the RFQ could be accepted easily and smoothly by the following super-conducting linear accelerator.</span