碳热还原法制备Ti(C,N)粉末

研究了用淀粉作为碳源还原氢化钛制备碳氮化钛纳米粉的工艺及利用热力学计算分析了反应机理。结果表明 :在实验范围内 ,降低合成温度、缩短保温时间或提高氮气流量有利于形成氮含量高的碳氮化钛粉末。通过控制合成温度和保温时间 ,可以控制Ti(C1 -xNx)中的碳氮比 ,得到不同x值的碳氮化钛粉末。实验结果与理论计算相一致     

前驱体碳热还原法制备纳米V（C1-xNX）粉体

以偏钒酸铵粉末和纳米碳黑为原料,先制成含有钒源和碳源的前驱体粉末,再置入真空碳管炉中,通入氮气进行碳氮化合成V(C1-xNx)粉体,采用TG/DSC热分析、XRD、SEM和TEM等测试方法对不同合成温度下的反应产物进行了表征,结果表明:前驱体粉末可以获得混合充分均匀的反应物原料,并在1 050～1 100℃之间制备了相组成单一、平均粒径60nm的纳米级V(C1-xNx)粉体;当温度低于1 050℃,粉体粒度小于100nm,但反应产物中有V2O3杂相生成;当温度高于1 100℃时,随着温度的升高,粉体的粒度逐渐长大,在1 200℃时颗粒之间熔融桥联.在1 000～1 100℃温度范围内,温度对粉体的x值影响不大,当温度高于1 100℃时,x值明显减小,说明V(C1-xNx)粉体中的碳含量显著增多,氮含量明显减少.     

(Ti,W)(B,C,N)纳米晶粉末的合成

以偏钛酸、偏钨酸铵、木糖、硼酸为原料,采用"前驱体+碳热还原"法合成了(Ti,W)(B,C,N)纳米晶粉末。利用SEM、XRD等表征产物相组成和显微形貌,重点探讨了合成温度、保温时间对合成产物的影响。结果表明,合成温度、保温时间均对(Ti,W)(B,C,N)粉末合成有显著影响,随着合成温度的提高以及保温时间的延长,合成粉末晶粒尺寸呈明显长大趋势。在合成温度1 200℃,保温时间2h条件下成功合成了晶粒度约为21.3nm的(Ti,W)(B,C,N)纳米晶粉末。与传统的"普通球磨+碳热还原"法比较,"前驱体+碳热还原"法显著降低了合成温度,并具有原料成本低廉的优势。     

Ti(C1-xNx)系固溶体粉末的组织结构研究

研究了碳热还原反应产业化制备的Ti(C1-xNx)系固溶体粉末的组织结构特征。结果表明,通过控制原料成分C／Ti的准确配比,可产业化制备出成分优良的不同单相Ti(C1-xNx)固溶体。粉末呈多角状和不规则形。Ti(C1-xNx)系固溶体的点阵常数与C或N含量有很好的对应关系。通过调整粉末中元素的固溶度,可控制粉末的晶体结构,进而控制材料的性能。     

WC粉末粒度对Ti(C,N)基金属陶瓷组织和性能的影响

研究了WC粉末粒度对Ti(C,N)基金属陶瓷Ti(C_(0.7)N_(0.3))-15%WC-15%Ni显微组织和性能的影响。研究结果表明,降低WC粉末粒度后组织中出现了大量的白芯-灰环结构的晶粒,总体晶粒度均匀并得到细化(2μm以下)。细化的WC粉末不仅使WC的溶解速度增大,Ti(C,N)的溶解速度也增大。细化WC粉末粒度可以提高金属陶瓷的硬度,但是断裂韧性却有所下降。     

“前驱体+真空碳热还原”法制备超细Mo_2C粉末的研究

利用"前驱体+真空碳热还原"法制备了超细Mo_2C粉末,采用XRD、FESEM等表征手段研究配碳量、合成温度以及保温时间对Mo_2C粉末微观形貌和物相组成的影响。结果表明:在配碳量为150%(质量分数)、合成温度1 150℃、保温2.0 h条件下制备的超细Mo_2C粉末,粒径约为100~500 nm。     

WC-10Co硬质合金热压工艺与晶粒抑制剂的研究

采用粒度为0 81μm的超细WC粉和粒度为1 35μm的Co粉,通过添加Cr3C2和VC作为晶粒长大抑制剂,采用热压(HP)烧结工艺制备了平均晶粒度小于0 8μm的WC-10Co硬质合金,检测了合金的显微硬度和显微组织。研究结果表明:随着烧结温度和保温时间的增加,WC-10Co硬质合金试样的显微硬度明显升高;添加晶粒长大抑制剂有效地抑制了晶粒的长大,明显提高了WC-10Co硬质合金的显微硬度;其中采用0 8Cr3C2+0 4VC晶粒长大抑制剂的样品显微硬度最高,达到22560MPa(2256kgf/mm2)。根据本实验研究结果,晶粒长大抑制剂对WC-10Co硬质合金作用效果的顺序为:(Cr3C2+VC)>Cr3C2>VC。     

自蔓延高温合成Ti_2SnC材料研究

以2Ti/Sn/C和Ti/Sn/TiC粉末为原料,采用自蔓延高温合成(SHS)技术合成Ti2SnC材料,并研究两种粉末原料对反应合成Ti2SnC的影响。研究结果表明,采用SHS技术以2Ti/Sn/C和Ti/Sn/TiC粉末为原料,均可合成Ti2SnC,产物中含有少量的TiC和Sn。以2Ti/Sn/C原料合成的Ti2SnC,其板条晶粒发育良好,晶粒长约10μm,宽约2μm;以Ti/Sn/TiC原料合成的Ti2SnC,其晶粒较细小,呈颗粒状,粒度约1~5μm。     

TiH_2/SiC粉末搅拌球磨及真空烧结制备超细晶钛

对TiH2/SiC混合粉末进行搅拌球磨,然后通过压制与真空烧结制备金属钛,研究球料比、球磨转速及球磨时间等工艺参数对球磨粉末粒度与显微组织的影响,并通过对烧结钛的组织观察与分析,研究此工艺制备超细晶钛的可行性。结果表明:适度提高转速或延长球磨时间有利于TiH2粉末的高效细化并提高粉末粒度分布的集中度;在球磨过程中没有发现TiH2分解和形成其他新相的现象;随球磨粉末的中位径D50和粒度跨度值ψ减小,烧结金属钛的晶粒度变得更小、更均匀。在600r/min转速下搅拌球磨8h后的TiH2/SiC粉末,在1050℃/3h条件下高真空烧结后得到平均晶粒度在5μm以下的超细晶钛。     

加热工艺对Nb-Ti微合金钢奥氏体晶粒长大的影响

 为了解加热制度对Nb Ti微合金钢的奥氏体晶粒长大和析出行为的影响,采用OM、TEM和EDS分析技术,研究了Nb Ti微合金钢在不同加热温度和保温时间的奥氏体晶粒长大行为,以及微合金元素碳氮化物析出行为。结果表明,随加热温度升高,奥氏体晶粒尺寸逐渐长大,当加热温度超过1 200 ℃时奥氏体晶粒尺寸快速长大。随保温时间延长,奥氏体晶粒尺寸逐渐长大,当保温时间超过2.0 h时奥氏体晶粒尺寸快速长大。EDS分析显示Nb Ti钢中的析出物为(Nb,Ti)(C,N)复合相,随着加热温度升高和保温时间延长,析出相体积分数减少,尺寸增大,从而减弱对奥氏体晶粒的细化作用;Nb Ti微合金试验钢合适的加热温度范围为1 150～1 200 ℃,保温时间低于2.0 h。     

转炉炉壳热应力分析

根据实际转炉建立实体模型。以有限元为手段,考虑了炉衬和炉壳材料的物性参数随温度变化的特点和炉衬与炉壳之间膨胀间隙,计算了转炉炉壳在温度载荷和炉衬膨胀压力同时作用下的热应力。所得结果可为转炉炉壳设计提供依据。     

焦炭热性能指标意义浅析

通过对焦炭在高炉内的历程及其变化规律的剖析,阐述焦炭热性能指标的意义,形象地把焦炭在高炉内的损耗分为三部分(M1,M2,M3)。指出M2对焦比及焦炭价格有一定的指导作用。     

Results of treatment of cancer of the cardia

Cancer of the cardia is traditionally discussed with cardiac cancer of the lower portion of the esophagus and upper gastric cancer invading the esophagus, and the specific characteristics of cancer of the cardia have never been clearly defined. We reviewed the outcome of 172 patients with adenocarcinoma of the cardia who had undergone radical surgery between 1949 and 1994 in the Division of Gastrointestinal Surgery of the Cancer Institute Hospital. The centers of the tumors were located within 2 cm above and below the boundary between the esophagus and the stomach, and their longitudinal diameter was less than 8 cm. We divided the patients into an early period (1949-1979; n = 79) and a late period (1980-1994; n = 93), and focused on the historical transition. There were no differences in patient gender or histology between the two periods. However, the late period was associated with fewer cases of esophageal invasion and shorter longitudinal diameter, as the age of the population advanced. The number of advanced cancers such as the localized and infiltrative type had decreased, and early cancer and early clinical stage had become more common, but despite the fact that the number of early cancers had increased, extended dissection, such as thoracic and paraaortic lymph node dissection, was performed more frequently. By clinical stage, the long-term outcome markedly improved in Stage I patient in the late period, and tended to improve in Stage II and III patients. This appears to have been attributable to the prevention of micrometastasis by extended dissection, although the number of early cancers is another major potential cause. There were no differences in the outcome of Stage IV patients between the two periods, and further advances in multimodality therapy must be awaited. The range of resection is basically proximal gastrectomy, and if there are adequate indications, the prognosis is favorable. In view of the status of lymphatic flow and lymph node metastasis, and long-term results, lateroaortic lymph node dissection is important. Since the number of early cancer patients has been increasing, if intraabdominal recurrence is prevented, intrathoracic lymph node dissection will contribute greatly to the outcome of such patients.     

The effect of amount of possession of the trait of hostility on accuracy of perception of hostility in others.

Some theories of personality hold that an individual's perception of others is influenced by his own personality characteristics; more specifically, that a trait of low social value will be projected more into others, and that insight into the possession of these characteristics reduces this distortion. These 2 hypotheses were tested by having a group of college students rate each other (including themselves) on degree of friendliness or hostility. Agreement with group rating about self yielded the insight score. In general, the hypotheses were supported; the "friendly" Ss were most accurate in their perception of others, and insight was positively associated with accurate perception. From Psyc Abstracts 36:04:4HL16M. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of antibiotics of chemotaxis of human leukocytes

The effect of 20 different antibiotics on chemotaxis by human neutrophils was studied. Human leukocytes incubated with chloramphenicol, rifampin, sodium fusidate, and tetracyclines in vitro showed markedly depressed migration. The mechanisms by which these antibiotics affect leukotaxis are discussed.     

Quality of life of relatives of mental patients

Usage of quality of life of psychiatric patients' relatives as the parameter of estimation of the quality of psychiatric care is considered. By means of standard questionnaire elaborated by the authors as well as by means of both individual and group conversations the quality of life was analyzed in 40 relatives which lived together with psychiatric patients. Different spheres of their life and difficulties (financial, social-psychologic, production) were examined in families with such patients. The defects of psychiatric care that had direct influence on the quality of life of the psychiatric patients' relatives are outlined.