Evaluation of the exploitation of nontraditional water resources—— Case study of Yantian District in Shenzhen

Yantian District in Shenzhen is a water deficient area. Water shortage has become a major obstacle to its further economic progress. Consequently, rational exploitation of nontraditional water resources(NWR)has been naturally adopted to increase local available water volume. The purpose of this paper is to analyse the exploitation of two kinds of NWR, namely wastewater reuse and seawater utilization, in Yantian District, and assess the contribution of each mode to deal with the water crisis. Two different nontraditional water supply systems respectively based on the reclaimed water and sea water were presented, and the effects of each system were evaluated in terms of technology, economy and environment. The result shows that both wastewater reclamation and reuse (WRR) and direct utilization of seawater (DUS) are of great importance to cope with the tight water resource situation in the district. The data indicate that the fresh water saved by WRR system and DUS system is 29 and 17 million m3/a respectively. Moreover, the BOD, COD, NH3-N and T-P reduced by the WRR system are 870, 2900, 725 and 87 t/a, respectively. Considering the integrated effectiveness, the development of WRR system, which is of specific significance to exploiting new water resource and save natural fresh water supplied from distant water diversion project, is the preferred methods used to solve the water shortage problem in Yantian District and recover the water environment as well as maintain the sustainable development of the city zone.     

无机/有机复合涂层体系在3.5%NaCl溶液中的EIS

采用电化学阻抗谱（EIS）研究了无机富锌底漆/环氧云铁中间漆/氯化橡胶面漆复合涂层体系在3.5%NaCl溶液中的腐蚀电化学行为,考察了紫外辐射对其电化学行为的影响。结果表明：复合涂层体系在3.5%NaCl介质中的腐蚀失效过程可以用4种等效电路来等效。浸泡失效前120 h,电解质溶液电阻R_c从开始的5×10⁹ Ω·cm²以大约2.2×10⁷ Ω·h^-1的速度迅速下降到4×10⁵ Ω·cm²,到浸泡120 h后R_c则以较小的速度808 Ω·h^-1下降,涂层电容C_c是按线性增加。紫外辐射不改变复合涂层体系在3.5% NaCl溶液中的电化学行为,仅仅加速复合涂层的失效。     

某高砷金矿氰化试验研究

某高砷金矿中金的品位为17g/t - 18g/t,砷的质量分数为20.15 % - 20.5%范围,硫的质量分数为18.46%,铅的质量分数为3.05%。金主要被砷化物及硫化物包裹不易氰化浸出。金矿直接焙烧后,金的氰化浸出率为56.17%,加入助剂焙烧后,金的氰化浸出率为81.48%以内。若在氰化反应体系中加入2 kg/t 增浸剂后,金的氰化浸出率为87%%-90%,金的氰化浸出速度得到提高。     

真空扩散焊热循环对2A14铝合金接头界面演变的影响

分别选取500,530,560 ℃焊接温度,进行2A14铝合金真空扩散焊,保温时间为60 min,焊接压力为4 MPa,真空压力低于3.4×10-3 Pa.焊后用扫描电镜(SEM)观察接头的焊合率、界面和母材组织形貌.结果表明,在500 ℃固溶线以下温度进行2A14铝合金扩散焊时,主要是界面微区塑性变形破碎氧化膜,实现局部微量的金属之间连接,焊合率很低.温度继续升高到530 ℃,超过固溶线温度,但小于Al-Cu共晶温度时,增加了界面CuAl2相结合机理,焊合率有明显提高.焊接温度在Al-Cu共晶温度以上,达到560 ℃时,CuAl2相完全溶解并在晶界生成共晶液相.该液相挤压、破碎界面氧化膜,并填充界面微孔,焊接接头界面呈正弦波状界面形貌,因而焊合率显著提高.根据这一分析结果,建立了晶界液相生成与界面氧化膜的破碎模型.     

Klebsiella sp.LSSE-H2的咔唑降解

从染料污染的土壤中分离出1株新的咔唑降解菌LSSE-H2,能以咔唑作为唯一的碳源、氮源和能源. 依据16S rRNA基因序列的系统发育分析将该菌鉴定为Klebsiella sp. 该菌在30℃、以咔唑为唯一的碳源、氮源的选择性培养基(CNFM)中,经过56 h可将浓度为12 mmol/L的咔唑几乎完全降解,在浓度为16 mmol/L的咔唑中也同样表现出高的咔唑降解活性. 对比分析不同营养成分培养基中对咔唑的降解情况表明,LSSE-H2可能存在独特的咔唑降解活性表达调控模式. 按照已公布的car基因簇序列设计同源引物,PCR扩增出LSSE-H2的包含5个咔唑降解基因的car基因簇片断,测序结果表明,咔唑降解基因高度保守,与Sphingomonas sp. KA1和Sphingomonas sp. GTIN11相应的咔唑基因的同源性都达到100%,只在基因簇的非编码区上发现少数碱基不同. 对比研究表明,LSSE-H2, KA1和GTIN11中car基因簇的起源可能相同,并能在不同的细菌之间水平转移.     

三元多碲化物纳米晶的新方法制备及表征

以硝酸银、氯化亚锡和碲粉为原料经微波溶剂热法制备纳米晶粉体Ag8SnTe6, 通过X射线粉末衍射(XRD)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)等手段表征其组成. 讨论了合成时间和有机溶剂填充度等条件对化合物产率和粒径的影响. 阐述了微波溶剂热法合成纳米晶的机理. 漫反射紫外可见吸收光谱(UV-Vis)表明其禁带宽度为2.58 eV,具有优良的半导体性能.     

焦炉加热过程模糊复合智能控制系统模型研究

采用"间歇加热控制"与加热煤气流量调节相结合的控制原理,利用模糊复合控制建立焦炉加热智能控制策略和模型.该控制策略采用前馈、反馈和模糊智能控制相结合,并应用结焦指数CI控制焦炉的炼焦过程.根据智能控制策略,设计了焦炉加热模糊智能控制的结构和模型.根据实际需要和人工经验,设计了焦炉加热的模糊控制器.仿真结果表明该系统能够稳定焦炉的炉温,具有很大的实用价值.     

乡村配电网供能范围与负荷调控技术协同优化方法

乡村用户较为分散、用电负荷密度低,其配电网设备利用率远低于城镇。各用户负荷曲线的波动特征不同,不同用户组合后总负荷曲线的平准化程度不同,对配电网的供能范围进行优化具有提升线路和设备利用率的潜力。同时,各类需求侧负荷调控技术的应用也可调整用户的负荷曲线,减小各用户的供电峰谷差。为实现乡村配电网规划和需求侧负荷调控方案协同优化,在对农村配电网构建成本、用户需求侧负荷调控成本进行数学描述的基础上,构建了用户聚合和各用户需求侧负荷调控协同优化模型,对各用户需求调控和配网线路供能范围进行综合优化。案例研究表明,对配电网供能范围和用户需求侧负荷调控措施进行协同优化,可以明显提升农网线路及附属设备的平均利用率,减少农村电网建设成本。     

酵母β-1,3-葡聚糖的酶法增溶及产物分析

本实验以酵母β-1,3-葡聚糖为原料,利用木霉菌株LE02产β-1,3-葡聚糖酶对其进行酶解增溶,并对酶解产物组分进行了分析,以得到最大量的可溶性多糖.结果表明,最佳酶解条件为55℃、pH4.5、底物浓度20%、酶用量4U/ml,酶解时间2h,可溶性多糖得率达到52%;不同水解时间酶解产物经Sephadex G-100凝胶过滤均可得到组分Ⅰ(大分子量多糖)、组分Ⅱ(寡聚糖)和组分Ⅲ(小分子量低聚糖和单糖)三个组分,随着水解时间延长组分Ⅰ比例下降、而组分Ⅲ的比例迅速上升.凝胶渗透色谱(GPC)测定水解2h酶解产物的分子量分布,其中分子量大于30kD组分占总糖的比例为66.2%.     

Protection behavior of fluorine-containing cover gases on molten magnesium alloys

The sulphur hexa-fluoride gas（SF6）, which is commonly used as the cover gas of molten magnesium alloys in the magnesium industry today, has an extremely high global warming potential（GWP）. The protection mechanism of SF6 containing cover gases on molten magnesium alloys was presented. The cover gas protects the melt by reacting with the melt to form a coherent protective film on the melt surface. The film contains MgO and MgF2. Particles containing MgF2 form on the interface between the oxide film and the bulk magnesium alloy, which correspond to the concave areas from the surface observation. These particles increase the Pilling and Bedworth ratio of surface film and enhance the protective capability of the films. Based on the understanding of the mechanism of SF6, a melting technology in a sealed furnace was proposed, and the protection behavior of magnesium alloys in the sealed melting furnace was investigated under the protective atmosphere containing HFC-134a. The morphology and composition of the surface film were also studied. Experiments to evaluate the protective effect of two other fluorine containing gases with low GWPs on AZglD alloy in the sealed furnace were also carried out, and the results show that the new gases are potential substitutes for SF6.