注射成型塑化过程的可视化实验研究

利用自行开发的可视化实验装置对注射成型的塑化过程进行了系统的观察,着重讨论了不同的工艺条件对塑化性能的影响,同时借助示踪粒子对塑化过程的重要参数——固相速度进行了测量。实验所取得的数据为注射成型熔融模型的建立和对模型的验证提供了依据,同时也是注射螺杆优化设计的基础数据。     

新型无污染融雪/冰剂的合成及应用评价

以天然矿石和乙酸为原料 ,采用正交试验法进行了新型无污染融雪 /冰剂的合成工艺研究 ,确定最适宜工艺条件为 :矿石与乙酸溶液的质量比为 1.2 ,乙酸浓度为 2 .6mol/L ,反应温度为 80℃ ,反应时间为 4～ 6h。介绍了新型融雪 /冰剂的机理、效果、对环境的影响 ,以及腐蚀性与毒性     

Multiple melting in blends of poly(vinylidene fluoride) with isotactic poly(ethyl methacrylate)

Multiple melting phenomena have been studied in blends of poly(vinylidene fluoride) (PVF₂) with low molar mass isotactic poly(ethyl methacrylate) (it-PEMA). In all blends, as well as in pure PVF₂, a transition (T₁) was observed prior to the main melting point (T₂). T₁ is probably connected with the melting of secondarily-crystallized material. In addition to this, a high temperature melting endotherm (T₃) was observed, which could be ascribed completely to recrystallization of PVF₂. The highest transition (T₄) was caused by melting of the σ form of PVF₂. From Hoffman-Weeks plots—T₂ vs. crystallization temperature, T_c — it could be concluded that no thermody amic depression of the melting point of PVF₂ occurred in the blends. The stabilities of PVF₂ crystallites in the various blends were derived from the slopes of Hoffman-Weeks plots and were in good agreement with lamellar thicknesses found from SAXS measurements.     

PEN/PTT共混聚酯的熔融行为

利用差示扫描量热仪对不同配比的聚萘二甲酸乙二醇酯/聚对苯二甲酸丙二醇酯(PEN/PTT)共混体系的熔融行为进行了分析,发现在共混体系中两组分形成各自的晶体,PEN和PTT的熔点均随另一组分含量的增加而下降。根据Nishi-Wang方程,按300℃计算,由PEN/PTT共混体系中PEN熔点下降计算所得到的相互作用能密度为-0．214 2 J/cm~3,相互作用参数为-0．006 8,表明PEN/PTY共混体系在熔融态是热力学性质稳定的相容体系。     

Sm~（3＋），Eu~（3＋），Tb~（3＋）等离子在低熔点玻璃中的光谱性质及

Ｓｍ￣（３＋），Ｅｕ￣（３＋），Ｔｂ￣（３＋）等离子在低熔点玻璃中的光谱性质及可见荧光的研究姜妍彦，王承遇，王继红（大连轻工业学院１１６００１）ＳｔｕｄｙｏｎＳｐｅｃｔｒａＰｒｏｐｅｒｔｉｅｓａｎｄＶｉｓｉｂｌｅＦｌｕｏｒｅｓｃｅｎｃｅｏｆＳｍ￣（３...     

醋酸装置催化剂循环使用周期短的原因及对策

根据乙醛氧化反应催化剂的循环使用机理对湘维醋酸装置催化剂循环使用周期短的原因进行了分析，找出了反应温度偏高、氧醛比偏大、醋酸锰循环使用流程不合理、用工业水溶解醋酸锰等四项原因，并提出了改进措施，实施后使湘维醋酸装置催化剂循环使用周期达到了国内先进水平。     

Texaco煤气化装置长周期运行影响因素分析

介绍了Texaco煤气化工艺流程,从原料煤种、水煤浆浓度、操作工艺、关键设备等几个方面讨论了影响装置长周期运行的因素,提出了延长气化装置运行周期的措施。     

Increasing urea-N efficiency for transplanted lowland rice by pneumatic injection: Yield and economics at the farm level

To increase the fertilizer-N efficiency in lowland rice (Oryza sativa L.) cultivation, new management practices are needed. Main cause of the present low efficiency is the low N recovery by plants, as a considerable part of the N applied is lost; deep placement techniques improve the recovery. A pneumatic injector, with which urea prills can be point-placed at a depth of 5–10 cm in paddy soils, was tested in 38 on-farm trials in 1989/90, mostly during the wet season. The experiments, located in Africa and Asia, focussed on differences in grain yield between conventional methods of broadcasting urea and injection by the pneumatic injector, at recommended N-rates. The study shows that the pneumatic injector is effective as a tool to improve the N fertilizer efficiency. The average yield increases per region, resulting from the use of the injector, ranged from about 250 to 1300 kg grain ha^–1. The value of the yield increase would allow most farmers to recover the costs of the injector within one season, even if labour was hired to carry out the injections. The average labour requirement of the injector was 40 hours ha^–1. In Indonesia, injection of prilled urea gave yields similar to those obtained with urea briquettes.     

聚丙烯熔融特性与MDSC条件的相关性

用调制式差示扫描量热法研究了聚丙烯(PP)升温过程熔融特性与线性升温速率（β)、温度调制振幅（AT)和调制周期(p)的相关性。实验结果表明，在低β时，总热流部分PP熔融呈现双峰；β加快时，呈现单熔融峰。随β加快，不可逆热流部分熔融热(△H)增加；可逆热流部分出现明显的放热峰。随p延长，总热流部分和不可逆热流部分的熔融峰温(Tp)基本不变，起始熔融温度(Ton)降低；但△H前者不变，后者增加；可逆热流部分从吸热变成放热，放热峰温移向高温。总热流和不可逆热流部分的Tp和Ton不受AT的影响，但随AT增大△H前者不变，后者降低。     

PP-R管材料熔融挤出过程MFR控制研究

分析了PP-R（无规共聚聚丙烯）管材料MFR（熔体流动速率）的变化对力学性能的影响，着重通过双螺杆挤出机研究了PP—R管材料熔融挤出过程中影响MFR变化的因素。结果表明，合适的加工工艺控制和优良的抗氧体系是保证PP-R管材料加工过程中MFR稳定的前提。