摘要：A baseline design for the High Energy Photon Source has been proposed, with a natural emittance of 60 *** within a circumference of about 1.3 kilometers. Nevertheless, the nonlinear performance of the design needs further improvements to increase both the dynamic aperture and the momentum acceptance. In this study, genetic optimization of the linear optics is performed, so as to find all the possible solutions with weaker sextupoles and hence weaker nonlinearities, while keeping the emittance at the same level as the baseline design. The solutions obtained enable us to explore the dependence of nonlinear dynamics on the working point. The result indicates that with the same layout, it is feasible to obtain much better nonlinear performance with a delicate tuning of the magnetic field strengths and a wise choice of the working point.

摘要：Protein chemical synthesis usually relies on the use of native chemical ligation that couples peptide thioester with a Cys-peptide. A limitation of this method is the difficulty of finding an appropriate Cys ligation site in many synthetic targets. To overcome this problem, the ligation-desulfurization approach has been developed. This approach involves the use of a thiol-containing amino acid as the ligation partner. After the sequence assembly is completed, the thiol group is removed through a desulfurization reaction to generate the standard amino acids. Currently this strategy has been applied to the ligations at a number of amino acids including Ala, Phe, Val, Lys, Thr, Leu, Pro and Gin. The present article reviews the design and svnthesis of these thiol-containing amino acids for native chemical libation at non-Cys sites.

摘要：On the basis of the study of volcanic products during 1199-1200AD eruption of Baitou Mountain (Baitoushan), the released volatile content was estimated by comparing Cl, F, S, H2O concentrations of undegassed glass inclusions with those of degassed matrix glasses. The calculations show that volatile yields, released from the melt, are 109.88×106 ton of HCI, 196.80×106 ton of HF, 1477.84×106 ton of H2O, 23.14×106 ton of SO2, which could have formed 35.43×106 ton of H2SO4 aerosol in the atmosphere. They could have substantial effect on paleoclimate and paleo-environment.

摘要：In the lattice design of a diffraction-limited storage ring（DLSR） consisting of compact multi-bend achromats（MBAs）, it is challenging to simultaneously achieve an ultralow emittance and a satisfactory nonlinear performance, due to extremely large nonlinearities and limited tuning ranges of the element parameters. Nevertheless, in this paper we show that the potential of a DLSR design can be explored with a successive and iterative implementation of the multi-objective particle swarm optimization（MOPSO） and multi-objective genetic algorithm（MOGA）. For the High Energy Photon Source, a planned kilometer-scale DLSR, optimizations indicate that it is feasible to attain a natural emittance of about 50 pm·rad, and simultaneously realize a sufficient ring acceptance for on-axis longitudinal injection, by using a hybrid MBA lattice. In particular, this study demonstrates that a rational combination of the MOPSO and MOGA is more effective than either of them alone, in approaching the true global optima of an explorative multi-objective problem with many optimizing variables and local optima.

摘要：In this paper, the "incompressible" property of a turbulent comhustion with Ma<<l is analyzed, and a pro- jection method for simulation of low Ma number turbulent combustions is discussed. The density is calculated explicitly, and the projection is only applied to the momentum equa- tions and thus greatly saves the calculation cost. Large eddy simulation of methane-air turbulent planar jet combustion is performed using this projection method. A reduced four-step chemical kinetic mechanism is applied for the simulation of methane-air combustion. A dynamic eddy viscosity model is utilized for the sub-grid scales turbulence modulation. The SGS model for the filtered reaction rate is a dynamic simi- larity model. Simulation results depict the detailed coherent structures in the jet flame along with the vortex-flame inter- actions in the flow field. Besides, it is fonnd that the chemical reaction has the effect of "energy rearrangement" in the flow field, which may greatly reduce the turbulence. Sinlulation results show the satisfactory performance of this projection method in simulating turbulent combustion under the condi- tion of Ma<<1.

摘要：为获取超声磨齿纵弯谐振系统的有效设计方法,基于局部共振理论,对磨削系统中的大负载成形砂轮盘振动系统进行设计与研究。根据振动单元间的连续条件和边界条件,按照一体式设计思路建立纵弯谐振系统的理论模型和频率方程。基于该理论模型,利用MATLAB、ANSYS等分析软件对系统各部分尺寸参数进行设计与优化,并进行有限元模态分析、阻抗分析试验和超声谐振试验。仿真与试验结果表明,系统谐振效果和振型曲线输出比较稳定,振幅与理论仿真预期结果相符,且系统实测谐振频率、设计频率以及仿真频率之间误差维持在5%范围内,具有较好的设计精度。从而,有效验证了基于局部共振设计理论的砂轮盘纵弯谐振系统设计方法的可行性及准确性。

摘要：A new generation of storage ring-based light sources,called diffraction-limited storage rings（DLSRs）,with emittance approaching the diffraction limit for multi-keV photons by means of multi-bend achromat lattices,has attracted extensive studies *** various DLSR proposals,the hybrid multi-bend achromat concept developed at the European Synchrotron Radiation Facility（ESRF） predicts an effective way of minimizing the emittance while keeping the required chromatic sextupole strengths to an achievable *** the High Energy Photon Source planned to be built in Beijing,an ESRF-type lattice design consisting of 48 hybrid seven-bend achromats is proposed to reach emittance as low as 60 pm-rad with a circumference of about 1296 *** dynamic aperture,allowing vertical on-axis injection,and moderate momentum acceptance are achieved simultaneously for a promising ring performance.

摘要：Traditional Global Sensitivity Analysis（GSA） focuses on ranking inputs according to their contributions to the output ***,information about how the specific regions inside an input affect the output is beyond the traditional GSA *** fully address this issue,in this work,two regional moment-independent importance measures,Regional Importance Measure based on Probability Density Function（RIMPDF） and Regional Importance Measure based on Cumulative Distribution Function（RIMCDF）,are introduced to find out the contributions of specific regions of an input to the whole output *** two regional importance measures prove to be reasonable supplements of the traditional GSA *** ideas of RIMPDF and RIMCDF are applied in two engineering examples to demonstrate that the regional moment-independent importance analysis can add more information concerning the contributions of model inputs.

摘要：Overview and research infrastructure As one of the leading laboratories in the interdisciplinary field of additive manufacturing and bio-3D printing,the Bio-Manufacturing Center at Tsinghua University is highly dedicated to conducting cutting-edge research in the emerging field of *** latter is comprised of research involving biomaterials,living cells,proteins,and/or other biological compounds as basic building blocks to fabricate biomimetic structures,in vitro functional biological models and/or cellular systems with application to tissue engineering,regenerative medicine,disease pathogenesis,drug screening,and tissue/organ-on-a-chip.

摘要：输水渠道作为线性工程对陆栖脊椎动物及其栖息地造成了直接和间接的负面生态影响,其阻隔作用造成栖息地片段化、动物迁移受阻、个体基因交流中断,并可改变动物个体行为、造成动物溺水致死、助长外来物种传播等。在全球范围内,大量的研究聚焦于公路、铁路,针对线性输水工程的相关研究十分薄弱,野生动物的保护措施多借鉴交通工程。本研究梳理了1970年以来国内外发表的相关研究案例,归纳了缓解输水渠道对陆栖脊椎动物生态影响的措施,包括设置保护围网、野生动物通道、逃离设施、植被缓冲带、人工饮水点等,并对其适用条件与范围、建设规格与参数、影响因素等进行了归纳和整理,以期为未来水利工程中野生动物保护措施的设计和环境影响评价、监测工作提供理论支撑。