The new molecular precursor Mg[OSi(OtBu)3]2 was synthesized in high yield from Mg(Bu)2 and HOSi(OtBu)3. Thermolytic decomposition of this precursor in toluene solution leads to a magnesia–silica monolith. The monolith can be processed to isolate xerogels or aerogels with surface areas of 245 and 640 m2 g−1, respectively. The MgO·2SiO2 materials are very acidic, as determined by ammonia temperature programmed desorption (TPD). Additionally, CO2 TPD revealed that these materials have a very low basic site density. The TPD results can be explained by a very high dispersion of MgO in an SiO2 matrix, and are consistent with predictions based on charge balancing in binary oxides.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTParticle counting by glow discharge perturbationNicholas A. Fedrick, Alexis T. Bell, and Donald N. HansonCite this: Environ. Sci. Technol. 1972, 6, 13, 1117–1118Publication Date (Print):December 1, 1972Publication History Published online1 May 2002Published inissue 1 December 1972https://pubs.acs.org/doi/10.1021/es60072a004https://doi.org/10.1021/es60072a004research-articleACS PublicationsRequest reuse permissionsArticle Views21Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
The design of new condensation polymers which undergo acid-catalyzed thermolysis is explored with polycarbonates. The polymers are prepared by phase-transfer catalyzed polycondensation using active esters or carbonates and diols. Polycarbonates containing tertiary, allylic or benzylic diol units susceptible to elimination decompose thermally near 200° to volatile materials. Self developing resist materials can be designed by combining the active polycarbonates with photoactive triarylsulfonium salts or other similar compounds which generate strong acids upon irradiation. Exposure of the resist material creates a latent image which can be developed thermally with evolution of volatile carbon dioxide, alkenes, and alcohols.
A mild method to prepare aryl and heteroaryl iodides by sequential C-H borylation and iodination is reported. The regioselectivity of this process is controlled by steric effects on the C-H borylation step and is complementary to existing methods to form aryl iodides. The iodination of boronic esters has potential for the synthesis of radiolabeled aryl iodides, as demonstrated by the concise synthesis of a potential tracer for SPECT imaging.
Conventional storage of large amounts of hydrogen in its molecular form is difficult and expensive because it requires employing either extremely high pressure gas or very low temperature liquid. Because of the importance of hydrogen as a fuel, the DOE has set system targets for hydrogen storage of gravimetric (5.5 wt%) and volumetric (40 g L-1) densities to be achieved by 2015. Given that these are system goals, a practical material will need to have higher capacity when the weight of the tank and associated cooling or regeneration system is considered. The size and weight of these components will vary substantially depending on whether the material operates by a chemisorption or physisorption mechanism. In the latter case, metal-organic frameworks (MOFs) have recently been identified as promising adsorbents for hydrogen storage, although little data is available for their sorption behavior. This grant was focused on the study of MOFs with these specific objectives. (1) To examine the effects of functionalization, catenation, and variation of the metal oxide and organic linkers on the low-pressure hydrogen adsorption properties of MOFs. (2) To develop a strategy for producing MOFs with high surface area and porosity to reduce the dead space and increase the hydrogen storage capacity per unit volume. (3) To functionalize MOFs by post synthetic functionalization with metals to improve the adsorption enthalpy of hydrogen for the room temperature hydrogen storage. This effort demonstrated the importance of open metal sites to improve the adsorption enthalpy by the systematic study, and this is also the origin of the new strategy, which termed isoreticular functionalization and metalation. However, a large pore volume is still a prerequisite feature. Based on our principle to design highly porous MOFs, guest-free MOFs with ultrahigh porosity have been experimentally synthesized. MOF-210, whose BET surface area is 6240 m2 g-1 (the highest among porous solids), takes up 15 wt% of total H2 uptake at 80 bar and 77 K. More importantly, the total H2 uptake by MOF-210 was 2.7 wt% at 80 bar and 298 K, which is the highest number reported for physisorptive materials.
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Calif. J. Politics Policy 2014; 6(2): 225–226 Commentary Liora G. Bowers*, Richard M. Scheffler, Stephen M. Shortell and Brent D. Fulton Introduction: Six Comments on the Forum Keywords: Berkeley Forum; global payments; healthcare; integrated care; leader- ship; multi-stakeholder collaboration. DOI 10.1515/cjpp-2014-0021 This special edition of the California Journal of Politics and Policy, in addition to the full report by the Berkeley Forum for Improving California’s Healthcare Deliv- ery System (hereafter “Berkeley Forum”), includes six brief comments by leaders in California’s healthcare system that reflect on the Berkeley Forum process and the fundamental healthcare system issues that dominated its discussions and shaped its recommendations. Ian Morrison, the Forum facilitator, offers insights on creating and manag- ing the project and provides invaluable advice for those seeking to create similar collaborations. Pam Kehaly, President of Anthem Blue Cross, acknowledges her initial skepti- cism of the project and its ambitions and describes the often circuitous and incon- clusive discussions in Forum meetings that, over time, evolved into consensus on a “Forum Vision” recommending a shift to integrated care and risk-adjusted global budgets. Kehaly concludes by noting the Forum leaders’ commitment to advance the Forum recommendations, and how Anthem Blue Cross is already doing so with its ACO-type provider contracts. Former Kaiser Chairman & CEO George Halvorson articulates a macro view of the key failure in the current system. He explains how buying health care by the piece encourages needless procedures and higher prices in pursuit of profit, discourages innovation in reengineering care, and financially rewards poor out- comes and ineffective care. The issues he raises played a major role in shaping the *Corresponding author: Liora G. Bowers, UC Berkeley, School of Public Health, Berkeley, CA, USA, e-mail: lgbowers@berkeley.edu; liora.bowers@gmail.com Richard M. Scheffler, Stephen M. Shortell and Brent D. Fulton: UC Berkeley, School of Public Health, Berkeley, CA, USA
