渐进镜的选架及瞳高的测量

渐进多焦距镜片与一般双光镜的不同,一般双光镜只有两个焦点,而渐进镜片不但上面能看远,下面可看近,并且自上光区到下光区有许多焦点,形成远近区中间有一个渐进区(图一),只要稍动头部就可以看清自远至近各种距离的物体。渐进镜也不象普通双光镜,看远看近有明显的分界线的光学跳跃感,以及戴普通双光镜给人年龄上有老的感觉。因此渐进镜进入市场后,受到了消费者的青睐。

An efficient strategy for the preparation of MIL-53(Al)-NH_(2)membranes with high ion selectivity and desalination performance

The efficient extraction of sodium(Na^(+))and lithium(Li^(+))from seawater and salt lakes is increasingly demanding due to their great application value in chemical industries.However,coexisting cations such as divalent calcium(Ca^(2+))and magnesium(Mg^(2+))ions are at the subnanometer scale in diameter,similar to target monovalent ions,making ion separation a great challenge.Here,we propose a simple and fast secondary growth method for the preparation of MIL-53(Al)-NH_(2)membranes on the surface of anodic aluminum oxide.Such membranes contain angstrom-scale(~7Å)channels for the entrance of small monovalent ions and water molecules,endowing the selectivities for monovalent cations over divalent cations and water over salt molecules.The resulting high-connectivity MIL-53(Al)-NH_(2)membranes exhibit excellent ion separation performance(a selectivity of 121.42 for Na^(+)/Ca^(2+)and 93.81 for Li^(+)/Mg^(2+))and desalination performance(a water/salt selectivity of up to 5196).This work highlights metal–organic framework membranes as potential candidates for realizing ion separation and desalination in liquid treatment.

基于德尔菲法探讨分析苗医肺架痛症

目的:基于苗医肺架痛症系统下对各症状条目进行筛查,为建立肺架痛症系统化认识及标准化诊断提供可靠依据。方法:通过文献检索和查找苗医学文献,收集肺架痛症主要症状,建立备选条目池;通过德尔菲法(Delphi)对贵州几家具有苗医药地域优势的医院进行两轮问卷调查,根据每轮调查结果进行统计分析、评价和筛查肺架痛症主要症状条目池。结果:通过文献检索纳入条目0项,苗医资料查阅纳入条目38项,共38项肺架痛症条目进入调查。每轮发放问卷20份,回收20份,回收率100%。删除重要性得分在3分及以下者,第1轮19项,第2轮7项,最终筛查出肺架痛症症状条目为咳嗽、咯黄色粘痰、胸痛、咳时胸痛、喘息、气急、发热、面色潮红、口干、舌红、苔黄、脉大而快等12项。其变异系数<0.25,专家权威程度平均为分(0.74±0.23)。结论:经本次调查分析专家积极度高、集中度高,所获咳嗽、咯黄色粘痰、胸痛、咳时疼痛、喘息、气急、发热、面色潮红、口干、舌红、苔黄、脉大而快12项肺架痛症症状条目池可作为肺架痛症临床评估及诊断的主要条目。

Design and 3D Printing of Scaffolds and Tissues

A growing number of three-dimensional(3D)-print- ing processes have been applied to tissue engineering. This paper presents a state-of-the-art study of 3D-printing technologies for tissue-engineering applications, with particular focus on the development of a computer-aided scaffold design system; the direct 3D printing of functionally graded scaffolds; the modeling of selective laser sintering(SLS) and fused deposition modeling(FDM) processes; the indirect additive manufacturing of scaffolds, with both micro and macro features; the development of a bioreactor; and 3D/4D bioprinting. Technological limitations will be discussed so as to highlight the possibility of future improvements for new 3D-printing methodologies for tissue engineering.

Effect of porosity on mechanical properties of porous tantalum scaffolds produced by electron beam powder bed fusion

The effect of porosity on compressive,bending,and tensile properties of the porous tantalum scaffolds fabricated by electron beam powder bed fusion(EB-PBF)was investigated.The porous tantalum scaffolds with porosity from 69%to 77.8%were obtained by varying the designed porosity and adjusting the processing parameters.It is found that the pores and unfused powder decrease with the increase of deposited energy density.The decrease of porosity leads to an improvement in mechanical properties.The relevancy between compressive/bending/tensile yield strength and relative density can be described appropriately by exponential model,while the relationship between elastic modulus and relative density is in good agreement with the Gibson-Ashby model.All the porous tantalum scaffolds exhibit good ductility in compressive,bending and tensile tests.No fragmentation of struts is observed during the compression process,but cracks are formed on the strut surface after 90°bending,mainly due to the high sensibility to defects caused by the oxide.

Adsorption behavior and mechanism of Hg(Ⅱ)on highly stable Zn-based metal organic frameworks

A novel adsorbent(MTZ-MOFs)was synthesized by a one-step reaction of zinc nitrate hexahydrate and 1-(2-dimethylaminoethyl)-1H-5-mercaptotetrazole to remove mercury from waste water.The results showed that MTZ-MOFs had excellent selectivity and repeatability for Hg(Ⅱ),the optimum pH was 3.0,the maximum adsorption capacity was 872.8 mg/g,and the process was a spontaneous exothermic reaction.The adsorption behavior was chemisorption,which conformed to the pseudo-second-order kinetic and Freundlich isothermal model.Moreover,the adsorption mechanism showed that the adsorption process mainly depended on ion exchange and chelation,and the synergistic action of S and N atoms played a key role.So,MTZ-MOFs were an efficient adsorbent for mercury ion removal.

Morphology evolution of acetic acid-modulated MIL-53(Fe)for efficient selective oxidation of H2S

MIL-53(Fe)was synthesized using a“modulator approach”that utilizes acetic acid(HAc)as an additive to control the size and morphology of the resulting crystals.We demonstrate that after activation under vaccum at 100℃,the MIL-53(Fe)functions well for H2S selective oxidation.The introduction of acetic acid in the presence of benzene-1,4-dicarboxylic acid(H2BDC)would result in a series of MIL-53(Fe)nanocrystals(denoted as MIL-53(Fe)-xH,x stands for the volume of added HAc with morphology evoluting from irregular particles to short hexagonal columns.The vacuum treatment facilitates the removal of acetate groups,thus generating Fe3+Lewis acid sites.Consequently,the resulted MIL-53(Fe)-xH exhibits good catalytic activity(98%H2S conversion and 92%sulfur selectivity)at moderate reaction temperatures(100–190℃).The MIL-53(Fe)-5H is superior to the traditional iron-based catalysts,showing stable performance in a test period of 55 h.

Means-End Chain Model Framework for Measuring Housing Environment Choice Behavior

Housing and housing space has been a place for personal development, recreation and self accentuation. The need for housing and housing space quality can therefore not be overemphasized. The need for housing remains a constant index for all societies through the ages. Housing is a complex and heterogeneous product in its setting, the cognitive structures of housing users for housing attributes is also complex as well as their choice behaviors. Means-End Chain （MEC） model has been found to be very effective and potent in measuring these complexities. This conceptual paper explores from literature the MEC model and attempts to propagate its use as a research model for housing research, environment-behavior studies and person-environment congruence. It also presents the methodology employed by MEC for data collection and data management. It will suggest an extension to the traditional methodology that MEC utilizes. The possibility of extending the previous methods and their applicability in design process is herein presented; and to make a case for the usability of MEC model as a research tool for housing researchers. In dealing with user preference of housing, there is a need for research for a development of a technological tool for the identification of user needs and preference, and the kind of decision support that are required to identify these needs.

Enhanced stability of highly-dispersed copper catalyst supported by hierarchically porous carbon for long term selective hydrogenation

Copper based catalysts have high potential for the substituent of noble-metal based catalysts as their high selectivity and moderate activity for selective hydrogenation reaction;however,achieving further high catalytic stability is very difficult.In this work,the carbonization process of Cu-based organic frameworks was explored for the synthesis of highly-dispersed Cu supported by hierarchically porous carbon with high catalytic performance for selective hydrogenation of 1,3-butadiene.The porous hierarchy of carbon support and the dispersion of copper nanoparticles can be precisely tuned by controlling the carbonization process.The resultant catalyst carbonized at 600°C exhibits a rather low reaction temperature at 75°C for 100%butadiene conversion with 100%selectivity to butenes,due to its reasonable porous hierarchy and highly-dispersed copper sites.More importantly,unprecedentedly stability of the corresponding Cu catalyst was firstly observed for selective 1,3-butadiene hydrogenation,with both 100%butadiene conversion and 100%butenes selectivity over 120 h of reaction at 75°C.This study verifies that a simply control the carbonization process of metal organic frameworks can be an effective way to obtain Cu-based catalysts with superior catalytic performance for selective hydrogenation reaction.

MIL-53(Al)derived single-atom Rh catalyst for the selective hydrogenation of m-chloronitrobenzene into m-chloroaniline

The catalytic hydrogenation of halonitroarenes to haloanilines is a green and sustainable process for the production of key nitrogen-containing intermediates in fine chemical industry.Chemoselective hydrogenation poses a significant challenge,which requires the rational design of the catalysts with proper hydrogenation ability for nitro group and simultaneously preventing dehalogenation of halogen group.Herein,a highly effective Rh@Al_(2)O_(3)@C single-atom catalyst(SAC)was developed for the hydrogenation of m-chloronitrobenzene(m-CNB)to m-chloroaniline(m-CAN),through an in-situ grafting of metal during the assembly of MIL-53(Al),followed by confined pyrolysis.Extensive characterizations reveal an exquisite structure of the Rh@Al_(2)O_(3)@C,containing atomically dispersed Rh sites onto Al_(2)O_(3) confined by the amorphous carbon.The five-coordinated aluminum(Al^(Ⅴ))species are essential for achieving the atomic dispersion of Rh atoms,providing the unsaturated coordinative sites for metal.Compared to the benchmark Rh/γ-Al_(2)O_(3) and Rh/C nanocatalysts,the Rh@Al_(2)O_(3)@C SAC affords an excellent turnover frequency of 2317 molm-CNB·molRh^(–1)·h^(–1),the highest value to date in heterogeneous catalyst systems for the hydrogenation of m-CNB at 313 K and 20 bar H2,together with a sustained selectivity to m-CAN(~98%)during five consecutive runs.The superior catalytic performance of the Rh@Al_(2)O_(3)@C is attributed to a proper modulation of electronic structure of hydrogenation metal by forming SAC,together with an enhanced accessibility of acid function sites.

A flexible metal-organic framework with double interpenetration for highly selective CO2 capture at room temperature

A flexible metal-organic framework of la Cu（FMA）（4,4＇-Bpe）0.s （FMA=fumarate; 4,4＇Bpe=trans-bis-（4-pyridyl）ethylene） that exhibits guest molecule-controlled gate-opening adsorption has been reported, in which the flexible pores can be enlarged by CO2 molecules rather than CH4 and N2 under a certain gate-opening pressure. The CO2 uptake can be sharply improved from 6.85 cm3 gq at 0.60 atm to 33.7 cm3 g^-1 at 1 atm due to the gate-opening effect, thus resulting in the notably enhanced adsorption selectivities for CO2/CH4 （32：1, v/v） and CO2/N2 （48：1, v/v） separations at room temperature.

Flexible 3D porous metal-organic framework exhibiting selective adsorption for H_2O over organic solvents

A new flexible 3D porous metal-organic framework （MOF） with 1D open nanotube, [Co2（/zs-CTAl）（dpe）（H20）2]n-6n（H20） （1） （CTA = cyclohexane-1,2,4,5-tetracarboxylic acid, dpe = 1,2-di（4-pyridyl） ethylene） has been prepared and structurally character- ized. Meanwhile, each 1D nanotubes filled with 1D water chain with dimension of 13.711 ~ 12.275/~2. Compound 1 represents a new example that collapse/deform upon dehydration/hydration and shows adsorb 1-120 selectively over organic solvents.

Novel supramolecular organocatalysts of hydroxyprolinamide based on calix[4]arene scaffold for the enantioselective Biginelli reaction

A series of novel supramolecular organocatalysts of hydroxyprolinamide based on the upper rim of calix[4]arene scaffold have been developed to catalyze enantioselective multi-component Biginelli reaction. Under the optimal conditions, the reactions occurred with moderate-to-excellent enantioselectivities (up to 98% ee). A plausible transition state constructed by the supra- molecular interaction of hydrogen bond and cation-π between catalysts and substrates has been proposed.

Enhancement of gas-framework interaction in a metal–organic framework by cavity modification

Originated from the pore space segmentation modification of a reported metal-organic framework （MOF） （NOTT-125）, a new porous MOF ZnX was obtained and characterized by single-crystal X-ray diffraction, elemental analysis, X-ray powder diffraction and TGA. The ZnX exhibits remarkable selective CO2 adsorption property compared with that of the NOTT-125, which should be attributed to the enhanced gas-framework interactions induced by the fragmented pore space in ZnX.

Review for chiral-at-metal complexes and metal-organic framework enantiomorphs

This review discusses chiral-at-metal complexes and introduces enantiomorphs from assembly structure.Owing to the diverse coordination number and activity of metal ions as chiral centers, abundant structures for chiral selectivity, catalysis, and polarized light-response are the notable advantages of the chiral-at-metal complexes. The rational design and preparation of linear multi-dentate ligands is a good choice to improve the stability of chiral complexes, such as multi-bonding structure for high stability as a self-limiting system. The bio-significance and potential application of chiral-at-metal complexes are discussed, such as the synergistic effect of catalysis and chiral selectivity of the metal center in enzymes.Enzyme could be remolded to replace the original central metal ions with highly active rare earth or precious metal ions to form artificial metalloenzyme or to remove the ‘‘redundant" part around the metal center to improve the accessibility of substrate. The polarized light-response mechanism of chiral opsin is introduced in relation to its role in animal migration. Metal-organic frameworks(MOFs) are crystalline and porous materials built from metal nodes or clusters and organic linkers and provide the possibility to prepare artificial enantiomorphs. The preparations, applications, and characterization methods of MOF enatiomorphs are therefore introduced. We hope this review inspires researchers at all levels of their career to consider the title topic in their own research in terms of its application and potential value.

An ultrastable and easily regenerated HOF for the selective storage and separation of light hydrocarbons

Recently,crystalline porous materials such as metal-organic frameworks（MOFs）and covalent organic frameworks（COFs）have attracted much interest not only in chemistry but also in materials science due to their tunable structures and functional channels.They have some inherent disadvantages of being difficult to solution process and recovery,which might limit their wide usage.