Al含量对Zr基块体非晶合金力学性能的影响

用铜模吸铸法制备了(Zr64.8/90Cu14.85/90Ni10.35/90)90+xAl10-x(x=-4,-3,-2,0,2,4,6)块体合金,利用X射线衍射仪(XRD)、万能试验机、显微硬度计和扫描电镜(SEM)研究了Al含量对Zr基块体非晶合金力学性能的影响。结果表明:随着Al含量的减小,合金先是从非晶相为主的非晶/晶体复合材料转变为完全非晶材料,接着转变为以晶体相为主的非晶/晶体复合材料,最后转变为完全晶体材料。表明通过调整Al的含量,可以制备出具有完全非晶结构的Zr基块体非晶合金。当x=-2时,即合金成分为Zr63.36Cu14.52Ni10.12Al12时,合金为完全非晶结构,该合金的室温压缩塑性应变达到20.6%,应力-应变曲线体现出了"加工硬化"特性,屈服强度σs、极限强度σm和断裂强度σf分别为1740.6,2030.7和1510.5 MPa。表明通过调整Al的含量,可以制备出具有优良室温压缩塑性的Zr基块体非晶合金。随着Al含量的减小,合金试样的显微硬度的总体趋势为先增大再减小。当x=2时,合金为非晶/晶体复合材料,该合金具有较高的显微硬度HV719.8。     

铜模吸铸与高能球磨制备Zr46Cu46Al8非晶合金的组织结构及晶化动力学研究

采用铜模吸铸法制备出直径3 mm的Zr₄₆Cu₄₆Al₈块体非晶合金, 利用高能球磨法获得了不同粒径的合金粉体, 通过X射线衍射仪、示差扫描量热仪、扫描电镜等测试手段及热力学计算方法, 研究了制备方法对非晶合金组织结构及晶化动力学的影响。结果表明, 块体合金和粉体合金均可获得完全非晶结构; 块体非晶合金玻璃转变和晶化过程具有明显的动力学效应; 单因素变量法制备非晶粉体的最佳参数为: 转速300 r·min-1, 球料比30:1, 球磨时间15 h; 相同条件下, 除过冷液相区外, 块体非晶合金热力学参数普遍高于非晶粉体, 且晶化放热更剧烈; 随着加热速率增大, 二者热力学参数均向高温区移动, 过冷液相区的宽度也逐渐增加; 块体非晶合金和非晶粉体的特征温度表观激活能数值相近, 块体非晶态合金的表观激活能较非晶粉体高, 热稳定性更优。     

Fe74Al4Sn2M2P10Si4B4系非晶合金带材的制备及其热、磁性能

利用单辊法制备了Fe74 Al4Sn2M2P10Si4B4(M为Nb、Mo、V)、Fe74 Al4SnzMo2P8Si4B4C2和Fe75Al4Sn2Mo2Nd1P8Si4B4非晶合金薄带,并测试了该非晶合金系的差示扫描量热曲线和动、静态软磁性能.结果表明,Fe74Al4Sn2NbzP10Si4B4非晶合金具有相对较宽的超冷液相区,其△Tx=51.41 K;而Fe74Al4Sn2MozP10Si4B4非晶合金具有较好的软磁性能,其最大磁导率μm=53.5×104,μe(1 kHz)=7.02×104,损耗P1.1T/50Hz=0.096 W/kg;Fe74Al4Sn2Mo2P8Si4B4C2非晶合金具有宽的超冷液相区和良好的软磁性能,其超冷液相区的宽度△Tx=48.81 K,μm=23.3×104,P1 1T/50 Hz=0.153 W/kg;Fe75Al4SnzMozNd1P8Si4B4非晶合金具有很宽的超冷液相区,其△Tx=60.06 K.     

Ti对Cu基块体非晶合金的玻璃转变动力学影响

本文选用非晶形成能力高,且在玻璃转变区和过冷液相区有高热稳定性的Cu46Zr47-xAl7Tix(x=0,1.5)块体非晶合金为研究对象。利用X射线衍射分析和差示扫描量热分析(DSC),研究了Ti元素的添加对于Cu基非晶合金玻璃转变动力学的影响。研究结果表明,在Cu46Zr47Al7块体非晶合金中用1.5%的Ti替代Zr之后,利用VFT方程分析得知合金的强度指数D由2.54增大到3.78,脆性指数m也从39减小到34,表现出了更高的玻璃形成能力。     

水雾化制备Fe_(74)Cr_2Mo_2B_4Si_4C_2P_(10)Sn_2非晶粉末的研究

采用水雾化法制备了Fe_(74)Cr_2Mo_2B_4Si_4C_2P_(10)Sn_2粉末,分析了雾化参数对粉末粒度、形貌等的影响,探讨了合金的非晶形成能力。结果表明,Fe-Cr-Mo合金有强的非晶形成能力,非晶化临界冷却速率约为10~4K/s;水雾化法可制备粒度小于175μm的非晶粉,通过调整工艺可对粉末粒度、形貌进行调控,制备的粉末形貌规则、松装密度高、氧含量低,合成粉芯具有较低的损耗。     

Nb含量对Zr55Cu30Ni5Al10块体金属玻璃热稳定性和力学性能的影响

在水冷铜坩埚中采用铜模吸铸法制备出直径Ф3 mm的(Zr0.55Al0.10Ni0.05Cu0.30)100-xNbx(x=0,2,4,6,8,10)合金试样,利用X射线衍射(XRD)、差热分析(DSC)、扫描电镜(SEM)以及准静态压缩试验方法研究了Nb含量对Zr55Cu30Ni5Al10块体金属玻璃的非晶形成能力、热稳定性、力学性能和组织的影响。研究结果表明,添加适量的Nb元素能提高Zr55Cu30Ni5Al10合金的热稳定性和非晶形成能力。当Nb含量为x=8时,合金具有最宽的过冷液相区(ΔTx=86 K)和最大的非晶形成能力(参数γ=Tx/(Tg+Tl)=0.416)。对于Zr55Cu30Ni5Al10合金,优化Nb元素掺杂量可以获得最佳的非晶形成能力和热稳定性。Nb的适量添加也有利于提高Zr55Cu30Ni5Al10块体金属玻璃的压缩断裂强度和塑性变形能力,其中x=8时,合金的压缩断裂强度和塑性应变量分别达到1877MPa和1.92%,并具有加工硬化现象。     

FeCoNbSiB块体非晶合金的铜模铸造及结构表征

本文以低纯硼铁合金为主要原料,用铜模铸造的方法制备出FeCoNbSiB块体非晶合金。用差示扫描量热分析（DSC）、X射线衍射（XRD）透射电电子显微镜（TEM）对合金的热物理性能及合金的结构进行了表征。并结合形核理论讨论了合金的玻璃形成能力。     

Al88Ni4Y6Er2非晶合金动力学性能

采用单辊旋淬法制备了Al88Ni4Y6Er2非晶合金,用X射线衍射(XRD)、差示扫描量热(DSC)测试手段研究了Al88Ni4Y6Er2非晶合金晶化过程中的动力学性能.发现Al88Ni4Y6Er2非晶合金晶化温度Tx与升温速率φ通过Vogel-Fulcher-Tammnann公式拟合后满足非线性关系.并根据Tx10≈Tk这种近似关系,求得Al88Ni4Y6Er2非晶合金的Kauzmann温度Tk为401 K,由此推断出VFT温度T0不大于401 K.     

Sn的添加对Mg-Cu-Y块体金属玻璃形成能力的影响

通过熔体铜模浇注方法制备了Mg65Cu25-xSnxY10（X=2，4，6）合金，并对它们的玻璃形成能力及晶化行为进行了研究。利用X射线衍射确定合金的非晶态性质，差示扫描量热计（DSC）分析合金的玻璃转变、晶化和熔化行为。结果表明：在Mg65Cu25-xSnxY10合金体系中，当X=2时，合金的玻璃形成能力最强，能形成的完全玻璃态试样的最大尺寸为3．2mm，其过冷液相区△Tx和约化玻璃转变温度Trg分别为57．6和0．586。同时合金的熔化曲线表现为单一吸热峰。随着sn含量的增加，非晶合金的玻璃转变温度Tg及初始晶化温度Txl。均呈现下降趋势，同时合金的玻璃形成能力逐渐下降。当X=4和6时，合金的晶化行为表现为明显的多级晶化。     

Pr基块体非晶的制备及特性研究

在铜模铸造条件下制备了直径5mm的P r61Cu19N i10A l10大块非晶合金,在普通DSC条件下观察了这种合金的玻璃转变温度。对制备的非晶合金进行晶化处理,测定了不同处理温度下的电阻率,观察了P r61Cu19N i10A l10块体合金的缓冷凝固组织。发现随晶化程度的增加,合金样品的电阻率下降,完全晶化后合金的电阻率比非晶态的电阻率低14%。P r61Cu19N i10A l10块体合金的缓冷凝固组织由大量细小规则的树枝状晶和少量共晶组织组成。     

2-Substituted-4-methoxybenzimidazole-based PDE4 inhibitors

A new family of PDE4 inhibitors based on a benzimidazole framework is described. Several of these compounds are orally bioavailable and show efficacy in in vivo models of inflammatory disease.     

稀土固体超强酸Ce4+-SO42-/ZrO2催化剂的制备及性能研究

将固体超强酸SO42-/ZrO2负载稀土铈,制备了新型催化剂Ce4+-SO42-/ZrO2,用于催化合成溴代正辛烷。考察了硝酸铈的质量百分浓度、焙烧温度、焙烧时间等因素对其催化性能的影响;并采用IR、XRD和Hammett指示剂法对其性能进行了研究。     

Antiinflammatory 2-benzyl-4-sulfonyl-4H-isoquinoline-1,3-diones: novel inhibitors of COX-2

A series of 2-benzyl-4-sulfonyl-4H-isoquinoline-1,3-diones was prepared. Members of this series are potent and selective inhibitors of cyclooxygenase-2 (COX-2) in both microsomal and cellular assays. Two representatives demonstrated activity in the carrageenan-induced paw edema model in rats upon oral administration.     

从氯化钴溶液中沉淀回收草酸钴

本文研究了从选择性电溶WC-Co废合金得到的氯化钴溶液中回收草酸钴的工艺条件。结果表明:酸效应、同离子效应均影响草酸钴的转化率。在适当的条件下,草酸钴的转化率可达99％。     

H_2O_2-Fe_2(SO_4)_3-H_2SO_4体系中辉铜矿的浸取研究

以H_2O_2和Fe_2(SO_4)_3为氧化剂、NaCl为助浸剂,在H_2SO_4溶液中浸出辉铜矿中的铜。结果表明,在反应温度85℃,反应时间180 min,H_2O_2、Fe_2(SO_4)_3、NaCl、H_2SO_4浓度分别为0.2、0.25、0.5、0.5mol/L的条件下,铜浸出率可达94.33%。采用XRD和EDS等手段对不同反应时间浸出残渣进行了表征与分析,初步揭示了辉铜矿浸取反应历程。     

Inhibition of 4-hydroxyphenylpyruvate dioxygenase by 2-(2-nitro-4-trifluoromethylbenzoyl)-cyclohexane-1,3-dione and 2-(2-chloro-4-methanesulfonylbenzoyl)-cyclohexane-1,3-dione

The administration of the compound 2-(2-nitro-4-trifluoromethylbenzoyl)-cyclohexane-1,3-dione (NTBC) to rats (10 mg/kg body wt) caused an elevation in the concentration of plasma tyrosine and gave products in urine that were identified as 4-hydroxyphenylpyruvate (HPPA) and 4-hydroxyphenyllactate (HPLA). This observed chemically induced tyrosinemia established that this compound perturbs tyrosine catabolism and suggested that the causal effect is the inhibition of 4-hydroxyphenylpyruvate dioxygenase (HPPD). This was confirmed when rat liver HPPD was found to be markedly inhibited by NTBC when the enzyme and chemical were incubated, in vitro, for 3 min at 37 degrees C prior to the initiation of the enzyme reaction by the addition of substrate. At 100 nM NTBC, approximately 90% of the enzyme activity was lost and an IC50 was calculated at approximately 40 nM. The inhibition of HPPD by NTBC (50 nM) is time-dependent; the enzyme activity was reduced by > 50% within 30 sec. Progress curve data of loss of enzyme activity with time gave a rate constant for the inactivation of rat liver HPPD [k*, formation of an HPPD-inhibitor (EI) complex] by NTBC of 9.9 +/- 2.5 x 10(-5) sec-1 nM-1. It was established that NTBC is not irreversibly bound in the EI complex but slowly dissociates with a recovery of enzyme activity of 13.7 +/- 1.0% over a 7-hr period (t1/2, 25 degrees C estimated at 63 hours). In comparison, the compound 2-(2-chloro-4-methanesulfonylbenzoyl)-cyclohexane-1,3-dione (CMBC), an analog of NTBC, gave a similar rate for the inactivation of HPPD (k*, 3.3 +/- 0.8 x 10(-5) sec-1 nM-1), whereas 45 +/- 8% of the enzyme activity was recovered over a 7-hr period (t1/2, 25 degrees C approximately 10 hr). These studies establish that NTBC and CMBC are potent, time-dependent (tight-binding) reversible inhibitors of HPPD. The inhibition is characterized by a rapid inactivation of the enzyme by the formation of an HPPD-inhibitor complex that dissociates with recovery of enzyme activity. In vivo, the inhibition of HPPD causes a tyrosinemia that abates with the recovery of enzyme activity. The understanding of the mechanism by which NTBC perturbs tyrosine catabolism has led to the clinical use of this chemical as the first effective pharmacological therapy for the hereditary disorder tyrosinemia I.