β-环糊精的KI-I_2分光光度法测定

基于β-CD引起KI-I_2混合液光谱变化的原理,获得了β-CD的KI-I_2分光光度测定法,并分析了不同实验条件对测定结果的影响。结果表明,以KI-I_2溶液为显色剂的分光光度法测定波长为430 nm,显色时间为30 min,工作曲线相关系数为0.999 7,检测范围为0.74~75 mg/L,pH 5~9范围内测定效果好,操作简单,共存的不水解、易水解无机盐及水体腐殖酸对测定的干扰小。利用KI-I_2分光光度法测定β-CD在土壤中等温吸附曲线,获得了较满意的效果。     

蒙脱石负载铜(Ⅱ)配合物的制备及吸附性能研究

通过离子交换和络合作用合成蒙脱石负载铜(Ⅱ)-水杨醛缩-β-丙氨酸复合材料[Cu(Ⅱ)-L/MMT]。采用XRD和FT-IR对该复合材料进行了表征,并考察了其对结晶紫的吸附性能及影响因素。结果表明,铜(Ⅱ)配合物已成功插入蒙脱石层间;溶液p H、复合材料投加量、吸附时间及结晶紫的初始浓度对复合材料吸附去除结晶紫有较大影响。与原土相比,[Cu(Ⅱ)-L/MMT]对结晶紫的去除效果明显提高。该复合材料对结晶紫的吸附等温线符合Langmuir模型,吸附行为符合拟二级动力学模型。     

卡非佐米的合成

卡非佐米(Carfilzomib)是一种α,β-环氧酮类蛋白酶体抑制剂,适用于多发性骨髓瘤的治疗。以L-苯丙氨酸苄酯为原料,经多步反应合成得到中间体2-吗啉乙酰-L-高苯丙氨酰-L-亮氨酰-L-苯丙氨酸。另以叔丁氧羰基(Boc)保护的L-亮氨酸为原料,经Weinreb酰胺化、格氏加成、环氧化及脱保护得到中间体S-2-氨基-4-甲基-1-(2S-环氧丙基)-1-戊酮三氟乙酸盐,上述两种中间体最终经缩合得到目标产物。关键中间体及产物经1HNMR和HR-MS确证结构。该合成方法反应条件温和、纯化简便、收率较高,适合大规模生产。     

Toward revealing atomic deformation mechanics in lithium disilicate and β-quartz containing glass-ceramics

The mechanics of glass-ceramics subjected to sharp contact or other loading conditions remain elusive, even after being commercialized in many industrial applications. We present work herein to reveal atomic details of such deformations that are otherwise extremely difficult to probe experimentally for a lithium disilicate (LS2) and β-quartz containing glass-ceramics via molecular dynamics simulations. Specifically, the materials are comprised of LS2 and β-quartz nanocrystals in a residual glass matrix. Regardless of the deformation mechanism, whether it be nanoindentation or crack propagation for samples with pre-existing flaws, we observe that the LS2 nanocrystal itself undergoes substantial deformation, either by activating dislocations, forming an amorphization zone, or by initiating microcracks at glass-crystal interfaces or weak crystallographic planes. In contrast, the β-quartz nanocrystal is not easily deformed and remains almost intact with minimal plastic deformation, thereby forcing shear flow and crack propagation pathways to predominately occur in the residual glass and/or at interfaces. The dramatic difference between the crystalline phases also manifests itself in the deformation mode of interfaces under pure shear loading, in which shear bands preferably occur at the LS2-glass interfaces, while cavities form at the β-quartz-glass interfaces. These observations significantly advance our understanding of glass-ceramics and pave ways to exploit the understanding for more applications.     

Preparation of hollow SiC spheres by combustion synthesis

Hollow spherical β-SiC was successfully prepared in argon by combustion synthesis using Si powder and polytetrafluoroethylene (PTFE) powder. The phase composition and morphology of spherical products can be controlled by adjusting the Si/C₂F₄ molar ratio (M_Si/(C2F4)). When M_Si/(C2F4) = 3, the phase content of β-SiC is the highest (up to 85.54%), and hollow spherical products obtained; When M_Si/(C2F4) ≥ 5, the Si/SiC microspheres are solid. The synthesis mechanism of hollow β-SiC microspheres is as follows: Si particles react with PTFE releasing heat. Then unreacted Si absorbs heat to form liquid phase microspheres, which is equivalent to the core template to form β-SiC microspheres by reaction with cracked C. Meanwhile, the silicon diffuses from the core to the shell to form the cavity. This method can synthesize the hollow spherical β-SiC in a simple way without prearranged spherical template and long synthesis cycle.     

Site-selective occupation and luminescence property investigation of Ca18Na3Y(PO4)14:Eu2+ phosphor for full-spectrum LED

Cyan-emitting phosphors have attracted widespread attention as an integral part to realize full-spectrum lighting. Understanding the site occupation of luminescence centers is of great importance to design and clarify the luminescent mechanism for new cyan-emitting phosphors. Here, we report a cyan-emitting phosphor Ca₁₈Na₃Y(PO₄)₁₄:Eu²⁺ synthesized by the high-temperature solid-state method. The crystal structure is characterized by X-ray diffraction and refined by the Rietveld method. The diffuse reflectance spectra, excitation/emission spectra, fluorescence decay curves, thermal stability, and related mechanism are systematically studied. The results show that Ca₁₈Na₃Y(PO₄)₁₄:Eu²⁺ crystallizes in a trigonal crystal system with space group R3c. Under excitation at 350 nm, a broadband cyan emission can be obtained at 500 nm with a half-width of about 120 nm, which is caused by Eu²⁺ occupying five different sites in host, namely, Na2O₁₂ (450 nm), (Ca3/Na1)O₈ (485 nm), Ca2O₈ (515 nm), Ca1O₇ (565 nm), and (Ca4/Y)O₆ (640 nm), respectively. Moreover, crystal structure, room and low temperature spectroscopy, and luminescence decay time are used to skillfully verify the site-selective occupation of Eu²⁺. Finally, a full-spectrum light-emitting diode (LED) lamp is fabricated with an improved color rendering index (∼90.3), CCT (∼5492 K), and CIE coordinates (0.332, 0.318). The results show that Ca₁₈Na₃Y(PO₄)₁₄:Eu²⁺ has the potential to act as a cyan emission phosphor for full-spectrum white LEDs.     

β-环糊精对曲拉通X-114紫外光谱抗干扰性能的影响

辛基苯基聚氧乙烯醚（曲拉通X-114）和脂肪醇聚氧乙烯醚（AEO-9）之间的相互作用能对水溶液中曲拉通X-114的紫外光谱产生明显影响。实验结果表明,在200～350nm范围内,曲拉通X-114的最大吸收波长为223nm,AEO-9的紫外吸光度接近于0;在水溶液中,AEO-9能减弱曲拉通X-114的紫外吸光度,降幅达3.4%;AEO-9还能显著降低曲拉通X-114的表观临界胶束浓度（cmc）,当AEO-9的浓度从0增加到0.050mmol/L 和0.100mmol/L时,曲拉通X-114的表观cmc从0.219mmol/L分别降至0.207mmol/L和0.202mmol/L。实验结果进一步表明,β-环糊精（β-CD）能有效降低AEO-9对曲拉通X-114的紫外吸光度及表观cmc的影响,在曲拉通 X-114和AEO-9复配水溶液中,按物质的量比1∶1加入β-CD,复配水溶液中曲拉通X-114的回收率从95.8%～103.3%变化至99.0%～100.1%,表明了β-CD能明显降低AEO-9对曲拉通X-114的干扰作用。红外光谱表征结果（FTIR）、核磁共振氢谱表征（¹H NMR）及热重差热分析表征结果（TG-DSC）表明,曲拉通X-114进入β-CD 分子空腔并形成包结物,是阻断曲拉通X-114分子形成混合胶束以及消除AEO对曲拉通X-114的干扰的主要原因。     

Ti(C,N)含量和烧结温度对梯度硬质合金脱β层厚度的影响

以Ti(C,N)为N源,在脱氮气氛下烧结制备WC-TiC-Ti(C,N)-TaC-NbC-Co硬质合金,研究Ti(C,N)含量和烧结温度对脱β层厚度及合金微观组织与性能的影响。结果表明:随Ti(C,N)的质量分数从0.5%增加到1.5%,脱β层厚度持续增大。随烧结温度升高,脱β层厚度增大,增大的幅度随Ti(C,N)含量增加而增大。合金的密度、硬度和矫顽磁力不受Ti(C,N)含量的影响,但随烧结温度升高,合金的硬度降低、矫顽磁力变小、WC平均晶粒尺寸增大且直边化。脱β层中无明显的WC晶粒异常长大现象,脱β层厚度由Ti的扩散和N含量决定。     

5α-氯-6β-羟基-雄甾-3,17-二酮的合成

以4-雄烯二酮为原料,经羰基保护、双键卤羟化、水解脱保护三步反应合成了5α-氯-6β-羟基-雄甾-3,17-二酮。讨论了保护试剂、催化剂、卤羟化试剂、反应温度等对实验结果的影响,得出了较佳工艺条件,三步总收率达到88%。     

Extraction of oil and β-sitosterol from peach (Prunus persica) seeds using supercritical carbon dioxide

Oil was extracted from the peach (Prunus persica) seeds by supercritical carbon dioxide. Principal phytosterols (stigmasterol, campesterol and β-sitosterol) that have been known to have cholesterol lowering properties were investigated in the extracted oil. Based on gas chromatography–mass spectrometry (GC–MS) analysis, β-sitosterol was identified in the peach seed oil. The effects of temperature, pressure, flow rate of supercritical CO₂, mean particle size of the seeds and extraction time on the amounts of extracted oil and β-sitosterol were investigated. Supercritical fluid extractions were performed in a range of 35–55 °C, 160–240 bar, 4–8 ml CO₂/min, 0.3–1.7 mm and 1–4 h for mentioned parameters. The results indicated that the amounts of oil and β-sitosterol extracted from the peach seeds were optimal with values of 35.3 g/100 g seed and 1220 mg/kg seed respectively at 40 °C, 200 bar, 7 ml/min, 0.3 mm and 3 h.