Comparison of modelled-and remote sensing-derived daily snow line altitudes at Ulugh Muztagh,northern Tibetan Plateau

The ice cap Ulugh Muztagh in the central Kunlun Shan at the northern fringe of the Tibetan Plateau is a very isolated region with arid cold conditions. No observational, meteorological or glaciological ground truth data is available. Using the Moderate-resolution Imaging Spectroradiometer(MODIS) Level 1 radiance Swath Data(MOD02QKM) with a spatial resolution of 250 m, transient snow lines during the months of July to September in 2001 to 2014 are derived. Results are used to calibrate the physical based Coupled Snowpack and Ice surface energy and Mass balance model(COSIMA). The model runs on a representative detail region of Ulugh Muztagh(UM) on a digital elevation model with the same spatial resolution as the MODIS bands. In the absence of field observations, the model is driven solely by dynamically downscaled global analysis data from the High Asia Refined analysis(HAR). We compare remote sensing derived and modelled mean regional transient snow line altitudes in the course of consecutive summer seasons in 2008 to 2010. The resulting snow line altitude(SLA) and annual equilibrium line altitude(ELA) proxy of both methods coincide very well in their interannual variability in accordance with interannual variability of climatic conditions. Since SLAs of both methods do notconsistently agree on a daily basis a usage of remote sensing derived SLAs for model calibration in the absence of field observation data is only limitedly feasible for daily analysis. ELA approximation using the highest SLA at the end of ablation period may not be applied to UM because the negative winter mass balance(MB) is not reflected in the summer SLA. The study reveals moderate negative MB for UM throughout the modelling period. The mean regional MB of UM accounts for-523±410 mm w.e. a-1 in the modelling period. Hence UM seems not to belong to the area of the ‘Karakorum anomaly' comprising a region of positive mass balances in recent years which has its centre presumably in the Western Kunlun Shan.

大学衍生企业:概念属性、创生动因与运行机制

在创新体系里大学衍生企业处于创新与市场的界面。"衍生企业"的基本含义是大学研究和技术转化出来的企业或大学员工创办的企业。大学衍生企业具有双重属性。一是它源自大学,大学文化、学科、机构、政策、人员等直接决定了大学衍生企业创设;二是接受市场检验,参与市场竞争。对大学衍生企业的研究立足于大学和市场,关注两者交互产生的影响,这对丰富企业组织理论具有学术意义。大学衍生企业不仅仅是长期存在的,而且还需要大力推进其发展。在衍生阶段大学的功能与作用显著,在成长发展阶段市场提供的风险资本、人力资源、营销网络等显得尤为重要。大学衍生企业成长进程是大学与企业交替作用的过程,但识别出在不同的阶段并采取相应的政策设计需要更为深入的研究,从而为我国推进大学衍生企业蓬勃发展提供政策设计的基础知识。

突发事件网络衍生舆情监测模型研究

分析突发事件衍生舆情传播特性,以突发事件网络舆情传播规律模型为铺垫,研究网络衍生舆情特点,通过定义描述舆情衍生程度的衍生率建立衍生舆情监测预警模型,并通过实例验证理论研究的可行性,以期为政府实现网络舆情管理提供参考。

Photolysis and Rate Constant of 2,3-butanedione with OH Radicals in the Aqueous Phase under Tropospheric Conditions

Photolysis rate （J1） and reaction rate constants （kl） for the biacetyl （butane-2,3-dione） were evaluated in aqueous phase using a continuous photolysis system with a conventional Xe-Hg arc lamp as a light source. The OH radicals was generated by H2OE/UV process and biacetyl （CH3C（O）C（O）CH3） concentrations were monitored using 2,4-DNPH derivatization method. 2,3-butanedione molecule is widely present in the atmosphere, it have been detected in hydrometeors （fogs, rain, and clouds） and at a significant yield （up to 10μmolar）. The measurements were performed at 294 K and with free pH values. Our results lead to the following obtained values： J1= 3×10^-4 S^-1 and k1 = （6.17±0.95）×10^8 M^-1·s^-1.The uncertainty listed above is ±15%.

Private Forest Owners Play Key Role in European Forest Derived Fuel Utilization

The AFO （activating private forest owners to increase forest fuel supply） project was set up to discover the best tools for activating an important fraction of the 12 million PFOs （private forest owners） in Europe to supply wood fuel, especially to small and medium-sized heating plants. It aimed to increase the utilization of Europe＇s vast forest fuel reserves. This was expected to benefit both the economy of the forest owners and rural areas and increase the use of renewable energy sources. The project was carried out between 2009 and 2012. The project operated in selected target regions that have a high proportion of private forest ownership （France, Slovenia, Latvia and the UK）. It started by analyzing the potential wood fuel supply and use in relation to current regional markets. After assessing through inquiries the potential wood fuel supply and demand and the parties involved, the next step was to initiate and support the formation of wood fuel supply clusters and organize supply chains. This was followed by the dissemination of best practice examples from Austria and Finland--countries with the most expertise and long traditions of forest fuel production. In the last phase of the project, results and approved activation methods were disseminated to all 27 EU （European Union） countries.

在4/2随机波动率下正态调和稳态过程模型对期权的定价和对冲

本文把4/2随机波动率添加到用于模拟资产价格的正态调和稳态过程中,得到了一种全新的Lévy随机波动率模型.更进一步地,本文在此基础上还构造了考虑杠杆效应的Lévy随机波动率模型.本文从数学上证明了模型可行性,并且推导了在这种模型下可被半显式表达出来的期权定价公式和对冲策略公式.作为应用,本文还推导了在上面模型下VIX(波动率指数)波动率衍生品的定价公式,最后数值检验证实了模型的实用性.

The generalized Bouleau-Yor identity for a sub-fractional Brownian motion

Let SH be a sub-fractional Brownian motion with index 0 〈 H 〈 1/2. In this paper we study the existence of the generalized quadratic eovariation [f（SH）, SH]（W） defined by[f（SH）,SH]t（W）=lim ε↓0 1/ ε2H ∫t 0 {f（SH s＋ε）-f（SH s＋ε）-f（SH s）}（SH s＋ε -SH s）ds2H, provided the limit exists in probability, where x → f（x） is a measurable function. We construct a Banach space X of measurable functions such that the generalized quadratic covariation exists in L2 provided f ∈ X. Moreover, the generalized Bouleau-Yor identity takes the form -∫R f（x） H（dx,t）=（2-2 2H-1）[f（SH ）,SH]t（w） for all f ∈ where H （X, t） is the weighted local time of SH. This allows us to write the generalized ItS＇s formula for absolutely continuous functions with derivative belonging to .

Hydrophobe-substituted bPEI derivatives: boosting transfection on primary vascular cells

Gene therapy targeted to vascular cells repre- sents a promising approach for prevention and treatment of pathological conditions such as intimal hyperplasia, in-stent and post-angioplasty restenosis. In this context, polymeric non-viral gene delivery systems are a safe alternative to viral vectors but a further improvement in efficiency and cytocom- patibility is needed to improve their clinical success. Herein, a library of 24 branched polyethylenimine （bPEI） derivatives modified with hydrophobic moieties was synthesised, char- acterised and tested in vitro on primary vascular cells, aim- ing to identify delivery agents with superior transfection effi- ciency and low cytotoxicity. Low molecular weight PEIs （0.6, 1.2 and 2 kDa） were grafted with long （C18） and short （C3） aliphatic chains, featuring different unsaturation degrees and degrees of substitution. 0.6 kDa bPEI-based derivatives were generally ineffective in transfection on vascular smooth mus- cle cells （VSMCs）, while among the other derivatives some promising vectors were identified. Forcing polyplexes on the cell surface by means of centrifugation invariably boosted transfection levels but increased cytotoxicity as well. Of note, a propionyl-snbstituted derivative （PEI2-PrA1, C3：0） was the most effective on both VSMCs and endothelial cells （ECs）, with higher and more sustained gene expression in combi- nation with markedly lower cytotoxicity with respect to the gold standard 25 kDa bPEI. In addition, a linoleoyl-substi- tuted derivative （PEI1.2-LA6, C18：2） owing to its high effi- ciency in VSMCs and relative inefficacy in ECs, combined with tolerable cytotoxicity was proposed as a vector for spe- cific VSMCs targeting.

Efficiency enhancement of P3HT:PCBM polymer solar cells using oligomers DH4T as the third component

We assembled a ternary blend bulk heterojunction polymer solar cell(PSCs) containing P3HT(donor) and PC61BM(acceptor) incorporated with a small molecule oligomer, dihexyl-quaterthiophene(DH4T) as a third component. By optimizing the contents of DH4 T, we increased the power conversion efficiency of ternary P3HT:DH4T:PC61BM PSCs to 4.17% from 3.44% of binary P3HT:PC61BM PSCs under AM 1.5 G of 100 m W/cm2 intensity. The major improvement is from the increase of the short circuit current and fill factor that is due to the increased light absorption at short wavelength, the balanced charge carrier transportation and the enhanced hole evacuation by a DH4T-enriched layer at the anode interface. In this work, we demonstrated that the efficiency of the PSCs can be enhanced by using low-bandgap conjugated polymer and its oligomer as donors and fullerene derivatives as acceptors.