~(15)N标记L-亮氨酸

采用生物发酵法制备15N标记的L-亮氨酸。以实验室选育获得的突变株黄色短杆菌TLU53-8为出发菌株,研究适用于15N标记L-亮氨酸生产的实验配方、发酵工艺、提纯工艺。结果表明,菌株发酵产酸量18 g/L。产品中15N同位素丰度98%,15N纯度99%。此工艺适用于制备高品质15N标记L-亮氨酸,具有较高的经济价值。     

~(13)C,~(15)N_3-盐酸氨基脲合成方法的优化

采用13C,15N2双标记尿素和15N2标记水合肼为原料,经回流反应一步合成13C,15N3-盐酸氨基脲。通过单因素考察和正交实验对13C,15N3-盐酸氨基脲的合成工艺进行优化,得到最优反应条件为:15N2-水合肼与13C,15N2-尿素的进料摩尔比为1.4∶1,加热温度为135℃,反应时间为4.5 h。采用此优化合成条件单步合成反应收率90%,13C,15N3-盐酸氨基脲纯度≥98%,13C丰度≥97%,15N丰度≥99%。结果显示,该方法具有反应周期短,产物收率高,后处理简便易行等优点。     

~(13)C_3-三聚氰酸、~(15)N_3-三聚氰胺的合成工艺研究

研究了以稳定性同位素标记物13C-尿素和15N-氯化铵为原料制备质谱检测用内标物13C3-三聚氰酸、15N3-三聚氰胺的合成工艺;考察了温度、压力、溶剂等对产品收率的影响,优化了合成工艺,以良好收率合成了同位素内标试剂13C3-三聚氰酸和15N3-三聚氰胺。产品经高效液相色谱(HPLC)、质谱(MS)检测,化学纯度99%,同位素丰度98%。以上结果提示,所合成的13C3-三聚氰酸和15N3-三聚氰胺可作为同位素内标使用。     

103Pd-110Agm合金膜制备工艺研究

以103Pd和110Agm 为示踪剂,采用化学镀法制备了103Pd-110Agm合金膜,并优化了制备条件：对制得的103Pd-110Agm合金膜采用γ井型探测器进行定量分析,扫描电镜进行定性分析。结果显示,优化后的镀膜条件为：镀液组成为PdCl2(含放射性103Pd) 、AgNO3、Na2EDTA、NH3 、N2H4;Pd与Ag的摩尔比为9∶1;活化液PdCl2的浓度范围为0.5～2.0 mmol/L;金属离子总浓度为5～7 mmol/L;NH3浓度为2～4 mol/L;pH为10～12;N2H4浓度为10 mmol/L;Na2EDTA浓度为0.15 mol/L;恒温水浴槽保持温度为60 ℃,旋转搅拌器转速为40～60 r/min,反应时间为60 min。在以上镀膜条件下进行化学镀,可得到具有金属光泽的镀层。用载体预处理后,扫描电镜显示,镀层表面有晶粒生长,镀后清晰可见;定性分析结果表明,合金膜中有Pd、Ag元素存在。     

长链脂肪酸衍生物99Tcm-MAMA-(CH2)nCOOH的制备和生物分布

以短链二酸和N2S2类配体（MAMA）为起始原料，合成了4个长链脂肪酸衍生物MAMA-(CH2)nCOOH（n=14,15,16,17），通过与99Tcm-GH在沸水浴中加热30 min完成配体交换反应，实现了99Tcm的标记，其标记率均大于90%。正常小鼠的生物分布数据显示这4个标记物在心肌中均有一定的摄取（5 min时的放射性摄取百分数依次为5.73、5.52、4.82和4.03%ID•g－1），但血本底较高，而且血清除较慢，标记物能否参与脂肪酸尚需进一步研究。     

4-甲基咪唑双膦酸的合成及其~(99)Tc~m标记

以4-甲基咪唑为原料,通过N-烷基化、酯水解和磷酸酰化三步反应,合成1-羟基-2-(4-甲基-1H-咪唑基)-乙烷-1,1-双膦酸(M4IDP),目标产物和重要中间体通过IR、MS及1H NMR进行结构鉴定;采用Na99TcmO4标记M4IDP,得到标记物99Tcm-M4IDP,并测定其体外稳定性。结果显示,标记物的最佳标记条件为:反应时间30 min,反应体系pH为6,SnCl2.2H2O用量100μg,配体用量5 mg。在此条件下,标记率95%,室温下存放6 h,放化纯度95%,说明99Tcm-M4IDP具有较好的体外稳定性。     

~(15)N标记S-苄基-L-半胱氨酸含量及其同位素丰度检测

建立了一种测定发酵液中15N标记S-苄基-L-半胱氨酸(SBC)含量的高效液相色谱法(HPLC),该方法采用Cosmosil C18(5μm,150 mm×4.6 mm)色谱柱为分离柱,2,4-二硝基氟苯为衍生剂,0.05 mol/L乙酸钠缓冲溶液(pH=6.5,含10 mL/L N,N-二甲基甲酰胺)与V(乙腈)∶V(水)=3∶1为流动相,梯度洗脱,流速1.0 mL/min,检测波长为350 nm,柱温为30℃;并采用微量高温燃烧-质谱法对15N标记SBC样品的同位素丰度进行了检测。结果显示,SBC浓度为0.2~1.0 g/L时,与其峰面积呈良好的线性关系,y=3×106x-4.16×104,R2=0.998 6,平均加标回收率97.30%,检测限为3.95×10-4g/L,测定结果的相对标准偏差为0.55%;15N标记SBC丰度检测时,最小称样量为2 mg,最佳反应温度为530℃,反应时间为3 h;15N丰度测定值的相对标准偏差为0.17%。     

~(99)Tc~m直接标记洛美沙星方法研究

采用Na99TcmO4对洛美沙星进行了直接标记,并对标记条件进行了优化,确定99Tcm标记洛美沙星的最佳条件,并测定了标记物的体外稳定性和脂水分配系数。结果表明,最佳标记条件为洛美沙星3 mg,SnCl2.2H2O 150μg,pH=6,温度为60℃,标记时间为10 min,所得标记物的标记率95%,放化纯度可达96.98%;标记物体外稳定性良好,可在0.01 mol/L pH7.4的PBS中室温放置6 h,其放化纯度仍95%;99Tcm-洛美沙星为脂溶性化合物。以上结果表明,99Tcm直接标记洛美沙星的方法操作简单,标记率较高。标记物不需分离纯化,体外稳定性好。     

PET肿瘤显像剂~(18)F-氟乙基胆碱的自动化合成

18F-氟乙基胆碱(18F-FECH)是反映胆碱代谢的PET肿瘤显像剂,在肿瘤特别是脑肿瘤诊断中显示出良好的应用前景。为了方便临床应用,本工作利用PET-MF-2V-IT-I型18F多功能合成模块,自动化合成18F-FECH。首先18F-与1,2-乙二醇二对甲苯磺酸酯在90℃下发生亲核取代反应,产物未经纯化即与N,N-二甲基乙醇胺在100℃下发生烷基化反应,此后经过C18柱和CM柱进行分离纯化,得到目标产物。整个过程需时约40 min,最终产品放化收率30%(未经时间校正),放化纯度≥99%,室温下可稳定放置6 h。本方法简便易行,合成时间短,收率较高,产品稳定性好,且其它各项指标均符合规定,为临床常规应用提供了保证。     

稳定同位素~(13)C标记乙醇

以Ba13CO3为原料,采用碳化锂方法制备乙炔,再经催化水合法和NaBH4还原,制备了13C-乙醇。考察了反应温度、助催化剂等合成工艺对产物收率的影响。设计的合成路线反应条件温和,总收率高于50%。产品经红外、色谱和核磁检测,化学纯度99%,13C同位素丰度95%,产物的同位素丰度相对原料而言降低3%。     

流加对前体物发酵法合成15NL色氨酸的影响

以经过诱变和5-甲基色氨酸处理的假丝酵母突变株AS60为出发菌株，研究了在前体物发酵合成15NL-色氨酸过程中，分别流加葡萄糖、15N硫酸铵及15N邻氨基苯甲酸对发酵的影响。结果表明：在发酵36h后，分别流加1.5 g/L 的15N邻氨基的苯甲酸、2.1 g/L的15N硫酸铵以及50 g/L葡萄糖时，可使发酵液中15NL-色氨酸的产量达到3.073g/L。     

The mineralization and transformation of both added organic nitrogen and native soil N in red soils from four different ecological conditions

The NH4^ -N,microbial biomass-N,humus-N,and extractable orgainc N derived from the added ^15N-labelled ryegrass and soil indigenous pool were measured separately with 15N tracing techniques.Based on the recovery of NH4^ -15N and lost-15N(mainly as NH3),more than 30% of the added ryegrass ^15N was mineralized in 15d.The amount of mineralized N increased with time up to 90d for all soils except for the upland soil in which it decreased slightly.The minearlization of ryegrass N and incorporation of ryegrass-15N into microbial biomass was greatest in upland soil.The transformation of ryegrass 15N into humus 15N occurred rapidly in 15d,with higher humus ^15N occurring in the upland or tea-garden soil than the paddy and unarable soil.The addition of ryegrass caused additional mineralization of soil indigenous organic N and enhanced the turnover of both microbial biomass N and stable organic N in soils.     

瞬发伽玛活化分析中3种探测器性能比较

利用中国先进研究堆(CARR)热中子束流孔道首次开展了瞬发伽玛中子活化分析(PGNAA)实验。对NH4Cl、Si、Fe、Al等4种样品进行了辐照,同时采用HPGe、LaBr_3、BGO 3种探测器对样品进行实时测量,在瞬发伽玛射线的能量为0.002~10 MeV范围内研究了3种探测器在宽能区的能量线性、能量分辨率、探测效率等性能。     

在盐酸体系中Ru(Ⅳ)的状态和萃取研究

本文研究了在[HCl]>3M介质条件下RuCl_6~(2-)的稳定性,它能被>5％TNA-煤油液溶定量萃取。用斜率法求得萃合物组成为[(R_3NH)_2RuCl_6]。同时研究了[TNA N_(1923)]、(TNA DNA)、(TNA ALQ)或(TNA MIBK)对RuCl_6~(2-)的协萃效应并着重研究了(TNA DNA)的协萃机理。在[HCl]>3M条件下,用等摩尔系列法求可能的萃合物为[(R_3NH)(R_2NH_2)_3Ru_2Cl_(12)]。协萃系数S=1.4。     

The Influence of Iron on Ammonium Ion Generation from Nitrate Ion in Liquid Phase

Flue gas cleaning in discharge plasma process has been Studied intensively and we have tried to remove the NOx and S02 using the wet-type plasma reactor. In this system, NO is oxidized to NO2 and absorbed as NO3^-, and SO2 is absorbed as SO3^2- and oxidized in the liquid to SO4^2-. But the concentration of NO3^- was saturated and the absorption of NOx and SO2 was inhibited. Then, the reduction of NO3^- in the liquid is required. We examined the reductive reaction of NO3^- to NH4^ using discharge above the liquid surface then the pH value of the liquid was changed to alkaline slightly. When the Fe plate was used as a ground electrode in the liquid, NH4^ was generated. Then, the relation between the generation of NH4^ and Fe ions (Fe^2 and Fe^3 ) was studied. When Fe^2 was presented in the liquid, NH4^ was generated and Fe^2 was oxidized to Fe^3 . Fe^2 is required to generate NH4^ from NO3^-. When NH4^ was generated from NO3^-, both the calculated pH value from NH4^ concentration and the measured pH value indicated a similar value. From these results, the discharge above the liquid surface was effective to convert NO3^- to NH4^ and the reductive reaction leads to more absorption of NO3^-. These results showed that the wet-type plasma reactor is effective for NOx and SO2 removal system.     

铀的离子交换反应——Ⅱ.硫酸和盐酸介质中铀(Ⅵ)在阳离子交换树脂上的化学状态

本文用红外光谱法和当量计算法研究了在硫酸、盐酸介质中铀(Ⅵ)在阳离子交换树脂上的化学状态及其含量。结果表明,在阳离子交换树脂上,铀(Ⅵ)除了以UO_2~(2 )外,还可以(UO_2HSO_4)~ 和(UO_2Cl)~ 存在,但当酸的浓度低于 0.5N时,其量可忽略不计。即使在酸浓度相当大(2—3N)时,(UO_2HSO_4)~ 和(UO_2Cl)~ 也只占树脂交换容量的很小一部分。因此,在通常用的阳离子交换色层法富集铀同位素的工作中,可以按照阳离子交换树脂上只有 UO_2~(2 )来考虑同位素效应及计算分离因数。     

TRPO流程中U的反萃：Ⅱ.（NH4）2CO3对U的反萃

研究了用 ５０ ｇ／ Ｌ（ Ｎ Ｈ４ ）２ Ｃ Ｏ３ 溶液从含 Ｕ 的 Ｔ Ｒ Ｐ Ｏ 相中反萃 Ｕ 的条件。测定了反萃平衡时间、相比、反萃次数、温度及有机相中 Ｕ 的质量浓度对反萃率的影响。用（ Ｎ Ｈ４）２ Ｃ Ｏ３ 反萃 Ｕ 比原流程的 Ｎａ２ Ｃ Ｏ３ 可减少 ２ 级,反萃液中不会析出（ Ｎ Ｈ４）２ Ｃ２ Ｏ４ 结晶。（ Ｎ Ｈ４）４［ Ｕ Ｏ２（ Ｃ Ｏ３）３ ］在加热转型时, Ｎ Ｈ＋４ 、 Ｃ Ｏ２－３ 及少量 Ｃ２ Ｏ２－４ 、 Ｎ Ｏ－３ 均可挥发除去。     

Chemical shift measurements of chlorine K X-ray spectra using a high-resolution PIXE system

A high-efficiency high-resolution wavelength-dispersive spectrograph with a von-Hamos configuration was developed for chemical state identification of elements in environmental samples using PIXE analysis. To evaluate the performance of this system, chlorine K X-ray spectra for NaCl, NH₄Cl and polyvinylchloride (PVC) targets were measured and compared. Also, to study the applicability to environmental mixed samples, mixtures of NaCl and NH₄Cl with different mixing ratios were measured. Through observation of Cl Kα₁ X-ray from NaCl, the energy resolution of the system was determined to be 1.1 eV. For the NaCl sample, a Kβ_x line was observed at an energy, which is higher than that of the Kβ main peak by 2 eV, whereas no Kβ_x emission was observed for the NH₄Cl sample. The chemical shift of the Kβ main peak for PVC relative to that for NaCl was about 1.2 eV. For NaCl-NH₄Cl mixture targets, the relative intensity of Kβ_x satellite to the Kβ main line provided an indication of mixing ratio. Energies and relative intensity of Cl Kβ X-ray satellites for NaCl and NH₄Cl samples calculated by a simple molecular-orbital method agreed only qualitatively with the experimental results.     

Accelerator mass spectrometry of 36Cl in limestone and some paleontological samples using completely stripped ions

Using the MP tandem—postaccelerator combination at the Munich Accelerator Laboratory, ³⁶Cl atoms extracted from various natural samples were accelerated to an energy so high that 7% of them were stripped of all their 17 electrons. This made it possible to use the isobar ³⁶S in macroscopic quantities as a guide beam to stabilize the whole system while still preserving perfect separation of ³⁶Cl and ³⁶S at the final stage. We now attain a detection sensitivity of up to 4 × 10^?15 for ³⁶Cl in natural chlorine. In the first experiments, the ³⁶Cl abundances of paleontological samples and the cosmic ray induced ³⁶Cl contents in limestone as a function of depth have been determined.