Modeling research in low-medium temperature geothermal field, Tianjin

The geothermal reservoir in Tianjin can be divided into two parts: the upper one is theporous medium reservoir in the Tertiary system; the lower one includes the basement reservoir inLower Paleozoic and Middle-Upper Proterozoic. Hot springs are exposed in the northern mountainand confined geothermal water is imbedded in the southern plain. The geothermal reservoir is in-cised by several fractures. In recent years, TDS of the geothermal water have gone up along withthe production rate increasing, along the eastern fracture zone (Cangdong Fracture and West Bai-tangkou Fracture). This means that the northern fracture system is the main seepage channel ofthe deep circulation geothermal water, and the reservoir has good connection in a certain area anddefinite direction. The isotopic research about hydrogen and carbon chronology indicates that themain recharge period of geothermal water is the Holocene Epoch, the pluvial and chilly period of20 kaBP. The karst conduits in weathered carbonate rocks of the Proterozoic and Lower Paleozoicand the northeast regional fracture system are the main feeding channels of Tianjin geothermalwater. Since the Holocene epoch, the geothermal water stayed at a sealed warm period. Thetracer test in WR45 doublet system shows that the tracer test is a very effective measure forunderstanding the reservoir's transport nature and predicting the cooling time and transportvelocity during the reinjection. 3-D numerical simulation shows that if the reinjection well keeps asuitable distance from the production well, reinjection will be a highly effective measure to extractmore thermal energy from the rock matrix. The cooling of the production well will not be a problem.     

KDP晶体固-液界面吸附行为的分子模拟研究

通过构建晶体表面-KDP分子界面吸附结构模型, 采用分子动力学和密度泛函计算方法研究KDP分子在(001)和(010)面吸附的物理化学过程, 考察了温度对物理吸附行为的影响. 研究表明: KDP晶体表面的吸附过程和生长习性主要由化学吸附主导, 化学吸附能的计算表明[K-O₈]基元在(001)界面的结合能是(010)界面结合能的2.86倍; 在饱和温度附近, [H₂PO₄]^-阴离子在KDP界面的物理结合能随温度的变化呈现振荡特征, 溶液中有较多的离子团簇形成, 溶液变得很不稳定; 当温度从323 K降低至308 K时, 水分子在界面的结合能总体呈下降趋势, 而KDP分子在界面的吸附能总体呈上升趋势, 脱水过程是水分子和[H₂PO₄]^-阴离子在固液界面边界层竞争吸附的结果. 研究结果对确足晶体生长界面动力学过程发展和完善晶体生长理论有重要意义. 关键词： 分子动力学 双层结构模型 结合能     

超固结土的一维固结理论及其试验研究

基于超固结饱和土固结理论,针对变荷载、自重应力分布等条件下提出3了相应的一维超固结土问题的控制方程,总结出六个超固结土的一维线性固结计算参数.并采用半解析法编制了求解该问题的Fortran计算程序.利用GDS高级固结仪对萧山黏土进行超固结土的一维固结渗透联合试验以及一维固结压缩试验,将测定的一维超固结土计算参数引入理论程序中,分别对比了位移、平均固结度、底部孔压这三者随时间变化的理论和试验曲线.结果表明:超固结土的一维线性固结理论比正常固结土的一维线性固结理论更接近试验结果,验证了超固结土的固结理论,表明了考虑土体应力历史对固结计算的重要性.     

考虑桩体内径向渗流的复合地基固结解

考虑了桩体内径竖向组合渗流和涂抹区土体水平渗透系数的两种变化模式,得到了此类固结问题的控制方程.采用新的初始条件,得到了控制方程的解答,给出了桩周土体和桩体内的平均孔压.在此基础上,把桩体的固结压缩引人对复合地基总平均固结度的定义中,分别给出了复合地基按应力和按应变定义的总平均固结度.结果表明:按应力和按应变定义的复合地基的总平均固结度相等;考虑桩体内径向渗流比不考虑桩体内径向渗流的复合地基固结度要小,而且随着桩间距的增大,两者之间的差值逐渐减小;考虑涂抹区水平渗透系数逐渐变化比假定涂抹区水平渗透系数保持不变的复合地基的总平均固结度大.     

A light scalar in the Minimal Dilaton Model in light of the LHC constraints

Whether an additional light scalar exists is an interesting topic in particle physics beyond the Standard Model(SM), as we do not know as yet the nature of physics beyond the SM in the low mass region in view of the inconsistent results of the ATLAS and CMS collaborations in their search for light resonances around 95 GeV in the diphoton channel. We study a light scalar in the Minimal Dilaton Model(MDM). Under the theoretical and the latest experimental constraints, we sort the selected data samples into two scenarios according to the diphoton rate of the light scalar: the large-diphoton scenario(with σ_(γγ)/SM■0.2) and the small-diphoton scenario(with σ_(γγ)/SM■0.2),which are favored by the CMS and ATLAS results, respectively. We compare the two scenarios, test the characteristics of the model parameters, the scalar couplings, production and decay, and consider how they could be further discerned at colliders. We draw the following conclusions for the two scenarios:(i) The large-diphoton scenario has in general a small Higgs-dilaton mixing angle(|sinθ_S|■0.2) and a small dilaton vacuum expectation value(VEV)f(0.5■η≡ v/f■1),and the small-diphoton scenario has large mixing(| sinθ_S|■0.4) or large VEV(η≡v/f ■0.3).(ii) The large-diphoton scenario in general predicts small syy coupling(|C_(sγγ)/SM|■ 0.3) and large sgg coupling(0.6■|C_(sgg)/SM|■1.2), while the small-diphoton scenario predicts small sgg coupling(|C_(sgg)/SM|■0.5).(iii) The large-diphoton scenario can interpret the small diphoton excess seen by CMS at its central value, when m_s■ 95 GeV,η■0.6 and | sinθ_S|■0.(iv) The large-diphoton scenario in general predicts a negative correlation between the Higgs couplings |C_(hγγ)/SMI and |C_(hgg)/SM|, while the small-diphoton scenario predicts that both couplings are smaller than 1,or |C_(hγγ)/SM|■0.9■|C_(hgg)/SM|.     

基于银纳米链的马赫-曾德干涉仪结构的生物传感器

优化了一种基于表面等离激元银纳米链的马赫-曾德干涉式传感结构.该结构由参考臂、传感臂及纳米线波导构成.纳米线波导由银纳米线包裹一定厚度的硅来构成.引入两条银纳米链分别作为马赫-曾德干涉仪的参考臂和传感臂,并研究所设计结构的传输特性,通过降低传输损耗以提高所设计结构的精确度与灵敏度.相比于两条完全相同的银纳米线作为参考臂和传感臂的情况,在参考臂和传感臂改为银纳米链后,传输特性有明显提高,单位长度损耗明显降低.这是由于银纳米链中的单元结构之间的长程/库仑相互作用增强了结构中的电磁场,进而降低了传输损耗.将两条银纳米链的晶格常数设置为不同的情况,研究发现,在特定的银包硅纳米线的宽度与某些占空比下,含有非对称的银纳米链结构的单位传输损耗小于含有对称的银纳米链结构.由此可以知道,具有小损耗的银纳米颗粒链可以弥补大损耗的银纳米颗粒链的传输损失.利用这个特点,进一步优化设计结构,将一侧银纳米链改为纳米线.改变另一侧银纳米链的晶格常数与占空比,可以发现大多数情况下,这类结构传输特性优于含有两条银纳米链以及含有两条银纳米线的结构.本文的设计结构可以大幅减小传统的马赫-曾德干涉仪的传输损耗,且在结构的制备...     

巯基丙酸修饰的硒化镉量子点检测银离子

通过水热法合成稳定的巯基丙酸修饰的水溶性硒化镉(MPA-CdSe)量子点,作为荧光探针检测水溶液中的银离子。该量子点对银离子表现出选择性荧光增强效应,并对其他共存的金属离子有很好的抗干扰性能。量子点的荧光增强与所加银离子浓度之间在0.1～1.2μM范围内呈现很好的线性关系,对银离子的检测灵敏度很高,检测限达到9.9nM。在实际水样中该方法对银离子检测的回收率为95%～120%,说明MPA-CdSe可以应用于实际水样中对银离子的检测。     

微型扬声器振动系统阻尼频率特性研究

受材料黏弹性的影响,微型扬声器振动系统的力阻与频率有关。通过理论推导建立了力阻与频率之间的模型,得到了微型扬声器振动系统力阻的计算公式,利用激光测振法测量得到的微型扬声器阻抗曲线和位移曲线可以方便地得到微型扬声器振动系统力阻频率响应,表明了其随频率增加而减小的频率特性。实验表明,采用该频率相关力阻模型计算阻抗曲线、位移曲线和频率响应曲线,与测量值吻合很好,明显好于传统频率非相关力阻模型所得曲线。     

聚乙二醇-硫酸铵双水相体系萃取分离镉(Ⅱ)

研究了硫酸铵-聚乙二醇2000双水相体系中Cd2+的萃取行为,探讨了酸度、KI、乙基紫(EV)、(NH4)2SO4用量对于Cd2+萃取率的影响.实验表明:在(NH4)2SO4存在下,聚乙二醇与水分相时,无法分离游离的Cd2+,对CdI24-的分离也不完全,而同样条件下加入毫克级EV后,Cd2+与EV、I-形成三元缔合物...