无捕收剂浮选提高金矿回收率试验研究

为建设环保矿山并提高金矿回峰率,进行了无捕收剂浮选的试验研究。对磨矿细度、调整剂用量、硫化钠用量、起泡剂用量等条件进行了研究。结果表明,采用无捕收剂浮选工艺,在原矿金品位16．75g／t,磨矿细度细度-0．074mm占60％、硫化钠用量600克／吨,2#油用量234．8g／t、浮选时间24min的情况下,可获得金精矿平均品位45．96g／t、回收率96．33％的技术指标。比选矿厂原生产指标（92％左右）提高了4％以上的回收率。     

水利水电工程地质-水工 三维协同设计系统研究

针对实现水利水电工程三维设计中所存在的关键问题,基于三维地质建模、水工建筑物快速建模和计算机协同设计技术等先进技术,采用了面向对象方法,设计并实现了水利水电工程地质-水工三维协同设计系统。该系统由三维地质建模、水工建筑物建模、工程地质分析与设计,以及数据库管理4个模块组成。地质和水工建筑物建模为工程地质分析与设计提供了三维模型,能够进行三维剖切分析、建基面分析、地下建筑物布置分析、边坡开挖分析等多方面的综合分析和不同专业间的协同作业,为水利水电工程三维设计提供了技术支持。     

基于统一混沌系统参数调制的保密通信方案

提出一类基于新近提出的统一混沌系统的参数自适应调制解调保密方案，利用Lyapunov函数方法对方案的可行性进行了证明，数值仿真实例表明了本方案的可行性；同时指出，如在保密通信装置的接收端加上一个低通滤波器（low pass fliter)，即使被携带传输的信号含有噪声也能被成功解调。     

碳绞线体外预应力梁的基频分析

通过理论公式推导、有限元软件（ANSYS）分析以及试验研究等方法,对体外预应力碳绞线对简支梁基频的影响进行了分析。理论公式推导中,利用由分布质量梁模型得到的自由振动方程,对Ayaho Miyamoto等人给出的公式进行了修正和扩充,考虑了预应力筋在锚固点既有水平位移又有竖直位移的影响;推导出各种线型布置下梁的自振频率计算公式。分析结果表明,体外预应力简支梁与普通钢筋混凝土简支梁的基频没有显著区别,近似计算方法具有实用性。     

广州市上下九路步行街环境心理学分析

将环境心理学作为指导商业步行街空间设计的中介,结合上下九商业步行街的空间表现形式,从街道形象、空间结点等方面论述了该商业街在设计中如何使空间环境与人的行为及心理需求达到合适化,并提出优化措施。     

The kinetic characterization of photofermentative bacterium Rhodopseudomonas faecalis RLD-53 and its application for enhancing continuous hydrogen production

In this work, the kinetic characterization of hydrogen production by the photofermentative bacteria Rhodopseudomonas faecalis RLD-53 was investigated at different growth phase. During entire fermentation, 89.30% of total biomass was accumulated in exponential growth phase, while hydrogen yield was only 1.82 mol H₂/mol acetate at the expense of 51.25% substrate. In the stationary phase, biomass synthesis was minimal (7.51%), and 38.17% of the substrate was directly converted into hydrogen. As a result, hydrogen (59.19%) was mainly produced in stationary phase with highest hydrogen yield of 3.67 mol H₂/mol acetate. Consequently, bacteria in stationary phase were most effective for hydrogen production. Based on these findings, a novel membrane photobioreactor was developed to retain bacteria during stationary phase in reactor through membrane separation. Maximum rate (32.82 ml/l/h) and yield (3.27 mol H₂/mol acetate) of hydrogen production were achieved using membrane photobioreactor under the continuous operation. Therefore, using bacteria in stationary phase as hydrogen producer can offer considerable benefits for enhancing photo-hydrogen production.     

Investigation on characteristics of ionization current in a spark-ignition engine fueled with natural gas–hydrogen blends with BSS de-noising method

Investigation on ionization current characteristic in a spark-ignition engine fueled with natural gas, natural gas–hydrogen bends and gasoline was conducted. Blind Source Separation (BSS) de-noising method is employed to separate the ionization current signal from the interference of spark tail generated by ignition discharge. Cylinder pressure was recorded, and local temperature at spark plug gap is calculated using AVL-FIRE simulation code. Results show that the simulated cylinder pressures are in good agreement with those of measured and the spark tail and ionization current can be separated using BSS method. Front flame stage and post flame stage in ionization current can be used to analyze the combustion characteristics of natural gas–hydrogen blends. De-noised current shows that the appearance of front flame stage and post flame stage (including the peaks in the stages) fueled with natural gas is postponed and compared with that fueled with gasoline, and the appearance of front flame stage and post flame stage advance with the increase of hydrogen fraction in natural gas–hydrogen blends. In addition, the amplitude of ionization currents in both front flame and post flame (including the two peaks) fueled with natural gas gives lower values compared with those fueled with gasoline and hydrogen addition can increase the amplitude. Maximum post flame current shows similar trend to maximum cylinder pressure and it has good correlation between the timing of maximum post flame current and the timing of maximum cylinder pressure. High correlation coefficient between maximum post flame current and maximum pressure is presented.     

TOOL PATH GENERATION BASED ON STL FILE FOR SHEET METAL DIELESS FORMING

Sheet metal dieless forming is a new metal forming technology. This technology adopts theprinciple of rapid prototyping technology, so it can form sheet metal parts without traditional die andmoulds. According to the charateristic of sheet metal dieless forming technology a new way of toolpath generation based on the STL file for sheet metal dieless forming is proposed.     

Epitaxy of In0.01Ga0.99As on Ge/offcut Si (001) virtual substrate

In_0.01Ga_0.99As thin films free of anti-phase domains were grown on 7° offcut Si (001) substrates using Ge as buffer layers. The Ge layers were grown by ultrahigh vacuum chemical vapor deposition using ‘low/high temperature’ two-step strategy, while the In_0.01Ga_0.99As layers were grown by metal-organic chemical vapor deposition. The etch-pit counting, cross-section and plane-view transmission electron microscopy, room temperature photoluminescence measurements are performed to study the dependence of In_0.01Ga_0.99As quality on the thickness of Ge buffer. The threading dislocation density of Ge layer was found to be inversely proportional to the square root of its thickness. The threading dislocation density of In_0.01Ga_0.99As on 300 nm thick Ge/offcut Si was about 4 × 10⁸ cm^− 2. Higher quality In_0.01Ga_0.99As can be obtained on thicker Ge/offcut Si virtual substrate. We found that the threading dislocations acted as non-radiative recombination centers and deteriorated the luminescence of In_0.01Ga_0.99As remarkably. Secondary ion mass spectrometry measurement indicated as low as 10¹⁶ cm^− 3 Ge unintended doping in In_0.01Ga_0.99As.     

智慧城市实操性规划探索-以广州天河智慧城为例

随着全球化和知识经济时代的到来,我国已迈入经济发展转型期,发展模式由粗放型、外延式向精细型、内涵式发展转变。这一时期,各城市均在谋求新的发展方式,产业从传统生产制造业向信息技术业提升,实现经济增长要素投入驱动转向创新驱动,提高城市核心竞争力。智慧城市作为新一代信息技术应用与展示的载体,已逐渐出现在各城市的战略方针和发展策略当中。随着信息网络化的普遍应用,人们的生产、生活方式发生转变,与之相对应的城市空间形态也发生了转变。基于此,研究以广州天河智慧城核心区控制性详细规划为例,挖掘智慧城市的内涵,从产业、生态、交通和设施四个方面探讨智慧城市在实操性规划中的诠释与应用。